Double stranded oligonucleotide compositions for RNA interference and methods relating thereto

Abstract

The present disclosure provides double stranded oligonucleotides, compositions, and methods relating thereto wherein the oligonucleotides comprise modifications of internucleotidic linkages. The present disclosure encompasses the recognition that structural elements of double stranded oligonucleotides, such as base modifications, as well as base sequence, chemical modifications (e.g., modifications of sugar and / or internucleotidic linkages) or patterns thereof, and / or stereochemistry, e.g., stereochemistry of chiral internucleotidic linkages, and / or patterns thereof, can have significant impact on oligonucleotide properties, e.g., RNA interference activity. The present disclosure also provides methods for treatment of diseases, e.g., hepatic diseases, central nervous system diseases, etc., using the provided double stranded oligonucleotide compositions.

Description

[0001] DOUBLE STRANDED OLIGONUCLEOTIDE COMPOSITIONS FOR RNA INTERFERENCE AND METHODS RELATING THERETO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to United States Provisional Application Nos. 63 / 679,508, filed August 5, 2024; 63 / 691,245, filed September 5, 2024; 63 / 744,330, filed January 12, 2025; and 63 / 750,252, filed January 27, 2025, the contents of which are incorporated by reference herein in their entireties.

[0003] This application incorporates herein by reference United States Provisional Application No. 63 / 620,768, filed January 12, 2024; United States Provisional Application No. 63 / 625,263, filed January 25, 2024; International Patent Application No. PCT / US2025 / 011458, filed January 13, 2025; International Patent Application No. PCT / US2025 / 013253, filed January 27, 2025; International Patent Application No. PCT / IB2021 / 000351, filed May 24, 2021; International Patent Application No. PCT / US2022 / 044296, filed September 21, 2022; International Patent Application No. PCT / US2024 / 018169, filed March 1, 2024; and International Patent Application No. PCT / US2025 / 018204, filed March 3, 2025.

[0004] BACKGROUND

[0005] Gene-targeting oligonucleotides are useful in various applications, e.g., therapeutic, diagnostic, research and nanomaterials applications. The use of naturally-occurring nucleic acids (e.g., unmodified DNA or RNA) in such applications can be limited by, for example, their susceptibility to endo- and exo-nucleases. As such, various synthetic counterparts have been developed to circumvent these shortcomings. These include synthetic oligonucleotides that contain chemical modifications, e.g., base modifications, sugar modifications, backbone modifications. There remains, however, a need in the art for double-stranded (ds) oligonucleotides with improved properties for use in connection with the above-described applications.

[0006] SUMMARY

[0007] The present disclosure is directed, in part, to the recognition that controlling structural elements of the oligonucleotides of a double-stranded (ds) oligonucleotide can have a significant impact on the ds oligonucleotide’s properties and / or activity. In certain embodiments, such structural elements include one or more of (1) chemical modifications(e.g., modifications of a sugar, base and / or internucleotidic linkage) and patterns thereof; and (2) alterations in stereochemistry (e.g., stereochemistry of a backbone chiral internucleotidic linkage) and patterns thereof. One or more of such structural elements can, in certain embodiments, be independently present in one or both oligonucleotides of a ds oligonucleotide. In certain embodiments, the properties and / or activities impacted by such structural elements include, but are not limited to, participation in, direction of a decrease in expression, activity or level of a gene or a gene product thereof, mediated, for example, by RNA interference (RNAi interference), RNase H-mediated knockdown, steric hindrance of translation, etc. Moreover, in certain embodiments, the properties and / or activities impacted by such structural elements include, but are not limited to, participation in, Ago2 loading, thermal stability, in vivo stability, delivery to tissues and into cells, among others.

[0008] In certain embodiments, the present disclosure demonstrates that compositions comprising ds oligonucleotides (e.g., dsRNAi oligonucleotides, also referred to as dsRNAi agents) with controlled structural elements provide unexpected properties and / or activities.

[0009] In certain embodiments, the present disclosure encompasses the recognition that stereochemistry, e.g., stereochemistry of backbone chiral centers, can unexpectedly maintain or improve properties of ds oligonucleotides. For example, but not by way of limitation, the instant disclosure relates, in part, to ds oligonucleotides comprising a guide strand comprising backbone phosphoryl guanidine chiral centers in the Sp configuration.

[0010] In a first aspect, the invention relates to a double-stranded RNAi (dsRNAi) agent capable of directing target-specific RNA interference, the dsRNAi agent comprising a guide strand and a passenger strand, wherein: the guide strand is complementary or substantially complementary to a target RNA sequence; the guide strand comprises a seed region at its 5’ end region that is capable of mediating the initial recognition of the target RNA sequence, e.g., nucleotides at positions 2-6, at positions 2-7, or at positions 2-8, relative to the 5 ’-end of the guide strand; the guide strand comprises a backbone phosphoryl guanidine (PN) chiral

[0011] center comprising the structure of,

[0012]

[0013] the 5p configuration, in the seed region, e.g., between the third (+3) nucleotide and the immediately downstream (+4) nucleotide, relative to its 5’ terminal nucleotide; and the guide strand comprises a contiguous or consecutive stretch of, e.g., five backbone phosphorothioate (PS) chiral centers, e.g., between the +13 nucleotide and the +18 nucleotide, relative to the 5’ terminalnucleotide, and / or a contiguous or consecutive stretch of, e.g., four backbone PS chiral centers, e.g., between the +19 nucleotide and the 3’ terminal (N) nucleotide, each independently in, e.g., the 5p configuration or the Rp configuration. In an exemplary embodiment, the contiguous stretch of five backbone PS chiral centers between the +13 nucleotide and the +18 nucleotide, relative to the 5’ terminal nucleotide, and the contiguous stretch of four backbone PS chiral centers between the +19 nucleotide and the 3’ terminal (N) nucleotide, of the guide strand, are in the A'p configuration. In an exemplary embodiment, the passenger strand comprises a backbone PS chiral center, e.g., between the 5’ terminal (+1) nucleotide and the immediately downstream (+2) nucleotide, and / or a backbone PS chiral center, e.g., between the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide, each independently in, e.g., the A'p configuration or the Rp configuration. In an exemplary embodiment, the backbone PS chiral center between the 5’ terminal (+1) nucleotide and the +2 nucleotide, and the backbone PS chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-l), of the passenger strand, are in the 5p configuration. In an exemplary embodiment, the guide strand further comprises a backbone

[0014] PN chiral center comprising the structure of,

[0015]

[0016] between the +7 nucleotide and the +8 nucleotide, and / or a backbone PN chiral center comprising the

[0017] structure of,

[0018]

[0019] between the +18 nucleotide and the +19 nucleotide thereof. In an exemplary embodiment, the backbone PN chiral center comprising

[0020] the structure

[0021]

[0022] between the +7 nucleotide and the +8 nucleotide, and

[0023] the backbone PN chiral center comprising the structure

[0024]

[0025] between the +18 nucleotide and the +19 nucleotide, of the guide strand, are in the 5p configuration. In an exemplary embodiment, the passenger strand comprises or further comprises a backbone

[0026] PN chiral center comprising the structure of,

[0027]

[0028] between the +7 nucleotide and the +8 nucleotide, and / or a backbone PN chiral center comprising thestructure of,

[0029]

[0030] between the +15 nucleotide and the +16 nucleotide, each independently in, e.g., the 5p configuration or the Rp configuration. In an exemplary embodiment, the backbone PN chiral center comprising the structure of

[0031]

[0032] between the +7 nucleotide and the +8 nucleotide, and the backbone PN

[0033] chiral center comprising the structure

[0034]

[0035] between the +15 nucleotide and the +16 nucleotide, of the passenger strand, are in the Ap configuration.

[0036] In an exemplary embodiment of the first aspect, neither the guide strand nor the passenger strand of the siRNAi agent comprises a lipid ligand or a non-lipid ligand.

[0037] In a second aspect, the invention relates to a double-stranded RNAi (dsRNAi) agent capable of directing target-specific RNA interference, the dsRNAi agent comprising a guide strand and a passenger strand, wherein the guide strand is complementary or substantially complementary to a target RNA sequence, and wherein the guide strand comprises one or

[0038]

[0039] more N-3 -uridine base modifications (N3U) having the structure

[0040] In certain embodiments, the guide strand comprises an N3U base modification at the 5’ terminal (+1) nucleotide. In particular embodiments, the guide strand comprises an N3U base modification at the 3’ terminal nucleotide, the penultimate (N-l) nucleotide, or at both the 3’ terminal nucleotide and the penultimate (N-l) nucleotide. In certain embodiments, the guide strand comprises an N3U base modification at the penultimate (N-l) nucleotide.

[0041] In a third aspect, the invention relates to a double-stranded RNAi (dsRNAi) agent capable of directing target-specific RNA interference, the dsRNAi agent comprising a guide strand and a passenger strand, wherein: the guide strand is complementary or substantially complementary to a target RNA sequence; the guide strand comprises a seed region at its 5’ end region that is capable of mediating the initial recognition of the target RNA sequence, e.g., nucleotides at positions 2-6, at positions 2-7, or at positions 2-8, relative to the 5 ’-end of the guide strand; the guide strand comprises a backbone phosphoryl guanidine (PN) chiralcenter comprising the structure of,

[0042]

[0043] the 5p configuration, in the seed region, e.g., between the third (+3) nucleotide and the immediately downstream (+4) nucleotide, relative to its 5’ terminal nucleotide; and the passenger strand comprises a

[0044] backbone PN chiral center comprising the structure of,

[0045]

[0046] between the 5’ terminal (+1) nucleotide and the immediately downstream (+2) nucleotide in, e.g., the Rp configuration. In an exemplary embodiment, the passenger strand further comprises a

[0047] backbone PN chiral center comprising the structure of,

[0048]

[0049] between the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide in, e.g., the Rp configuration. In an exemplary embodiment, the nucleoside 3’ to the PN chiral center in the seed region comprises a 2’-F ribose modification. In an exemplary embodiment, the guide strand further comprises a backbone phosphoryl guanidine (PN) chiral center comprising

[0050] the structure of,

[0051]

[0052] between the +10 nucleotide and the immediately downstream (+11) nucleotide, relative to the 5’ terminal nucleotide of the guide strand. In an exemplary embodiment, the nucleoside 3’ to the PN chiral center between the +10 nucleotide and the immediately downstream (+11) nucleotide, relative to the 5’ terminal nucleotide of the guide strand, comprises a 2’-F ribose modification. In an exemplary embodiment, the backbone phosphoryl guanidine (PN) chiral center between the +10 nucleotide and the immediately downstream (+11) nucleotide, relative to the 5’ terminal nucleotide of the guide strand, is in, e.g., the Ap configuration. In an exemplary embodiment, the guide strand comprises a 5’ phosphate modification, e.g., a 5’ phosphate mimic modification. In an exemplary embodiment, the 5’ phosphate mimic modification is, e.g.,

[0053]

[0054] , wherein: the base is, e.g., N3U, or is selected from, e.g., A, C, G, T, U, abasic, and modified nucleobases other than N3U; and R1is selected from, e.g., H,OH, O-alkyl, O-methyl (O-Me), F, O-methoxyethyl (MOE), and 2’-(9,4’C-methylene-bridged or locked nucleic acid (2’,4’-BNA or LNA). In an exemplary embodiment, R1is, e.g., O-methyl (O-Me). In an exemplary embodiment, the guide strand further comprises a backbone phosphoryl guanidine (PN) chiral center comprising the structure of, e.g.,

[0055]

[0056] between, e.g., the 3’ terminal (N) nucleotide and the penultimate (N- 1) nucleotide in, e.g., the Rp configuration, and / or a backbone phosphoryl guanidine (PN)

[0057] chiral center comprising the structure of,

[0058]

[0059] between, e.g., the penultimate (N-l) nucleotide and the immediately upstream (N-2) nucleotide in, e.g., the?p configuration. In an exemplary embodiment, the guide strand does not comprise a backbone phosphoryl guanidine (PN) chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide. In an exemplary embodiment, the guide strand does not comprise a backbone phosphoryl guanidine (PN) chiral center between the penultimate (N-1) nucleotide and the immediately upstream (N-2) nucleotide. In an exemplary embodiment, the guide strand comprises a phosphorothioate (PS) chiral center between, e.g., the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide in, e.g., the A'p configuration. In an exemplary embodiment, the guide strand comprises, e.g., a phosphoryl guanidine (PN) cap at, e.g., its 5’-end (5’-end PN cap). In an exemplary embodiment, the 5’-end PN cap is

[0060] selected from,

[0061]

[0062] wherein: the base is N3U, or is selected from, e.g., A, C, G, T, U, abasic, and modified nucleobases other than N3U; and R1is selected from H, OH, O-alkyl, O-methyl (O-Me), F, O-methoxyethyl (MOE), and 2’-(9,4’C-methylene-bridged or locked nucleic acid (2’,4’-BNA or LNA). In an exemplary embodiment, R1is, e.g., O-methyl (O-Me). In an exemplary embodiment, the guide strand comprises, e.g., a natural phosphate linkage (PO) between, e.g., the 5’ terminal (+1) nucleotide and the immediately downstream (+2) nucleotide, and / or, e.g., a natural phosphate linkage (PO) between, e.g., the +2 nucleotide and the +3 nucleotide, relative to the 5’ terminal nucleotide.In a fourth aspect, the invention relates to a double-stranded RNAi (dsRNAi) agent capable of directing target-specific RNA interference, the dsRNAi agent comprising a guide strand and a passenger strand, wherein: the guide strand is complementary or substantially complementary to a target RNA sequence; the guide strand comprises a seed region at its 5’ end region that is capable of mediating the initial recognition of the target RNA sequence, e.g., nucleotides at positions 2-6, at positions 2-7, or at positions 2-8, relative to the 5 ’-end of the guide strand; the guide strand comprises a backbone phosphoryl guanidine (PN) chiral

[0063] center comprising the structure of,

[0064]

[0065] the 5p configuration, in the seed region, e.g., between the third (+3) nucleotide and the immediately downstream (+4) nucleotide, relative to its 5’ terminal nucleotide; and the guide strand comprises a phosphoryl guanidine (PN) cap at its 5 ’-end (5 ’-end PN cap). In an exemplary embodiment,

[0066] the 5’-end PN cap is selected from,

[0067]

[0068] wherein: the base is, e.g., N3U, or is selected from, e.g., A, C, G, T, U, abasic, and modified nucleobases other than N3U; and R1is selected from, e.g., H, OH, O-alkyl, O-methyl (O-Me), F, O-methoxyethyl (MOE), and 2’-O,4’C-methylene-bridged or locked nucleic acid (2’,4’-BNA or LNA). In an exemplary embodiment, R1is, e.g., O-methyl (O- Me). In an exemplary embodiment, the guide strand further comprises a backbone

[0069] phosphoryl guanidine (PN) chiral center comprising the structure of, e.g.,

[0070]

[0071] (nOOl), between, e.g., the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide in, e.g., the Rp configuration, and / or a backbone phosphoryl guanidine (PN) chiral center

[0072] comprising the structure of,

[0073]

[0074] between, e.g., the penultimate (N-l) nucleotide and the immediately upstream (N-2) nucleotide in, e.g., the Rp configuration. In an exemplary embodiment, the guide strand does not comprise a backbone phosphoryl guanidine (PN) chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-1) nucleotide. In an exemplary embodiment, the guide strand does not comprise a backbone phosphoryl guanidine (PN) chiral center between the penultimate (N-l) nucleotide and the immediately upstream (N-2) nucleotide. In an exemplary embodiment, the guide strand comprises a phosphorothioate (PS) chiral center between, e.g., the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide in, e.g., the 5p configuration.

[0075] In a fifth aspect, the invention relates to a double-stranded RNAi (dsRNAi) agent capable of directing target-specific RNA interference, the dsRNAi agent comprising a guide strand and a passenger strand, wherein: the guide strand is complementary or substantially complementary to a target RNA sequence; the guide strand comprises a seed region at its 5’ end region that is capable of mediating the initial recognition of the target RNA sequence, e.g., nucleotides at positions 2-6, at positions 2-7, or at positions 2-8, relative to the 5 ’-end of the guide strand; the guide strand comprises a backbone phosphoryl guanidine (PN) chiral

[0076] center comprising the structure of,

[0077]

[0078] the 5p configuration, in the seed region, e.g., between the third (+3) nucleotide and the immediately downstream (+4) nucleotide, relative to its 5’ terminal nucleotide; and the guide strand comprises a natural phosphate linkage (PO) between, e.g., the 5’ terminal (+1) nucleotide and the immediately downstream (+2) nucleotide, and / or a natural phosphate linkage (PO) between, e.g., the +2 nucleotide and the +3 nucleotide, relative to the 5’ terminal nucleotide. In an exemplary embodiment, the guide strand comprises a 5’ phosphate modification, e.g., a 5’ phosphate mimic modification. In an exemplary embodiment, the 5’ phosphate mimic

[0079] modification is,

[0080]

[0081] wherein: the base is, e.g., N3U, or is selected from, e.g., A, C, G, T, U, abasic, and modified nucleobases other than N3U; and R1is selected from, e.g., H, OH, O-alkyl, O-methyl (O-Me), F, O-methoxyethyl (MOE), and 2’-O,4’C-methylene-bridged or locked nucleic acid (2’,4’-BNA or LNA). In an exemplary embodiment, R1is, e.g., O-methyl (O-Me). In an exemplary embodiment, the guide strand further comprises a backbone phosphoryl guanidine (PN) chiral center

[0082] comprising the structure of,

[0083]

[0084] between, e.g., the 3’ terminal (N)nucleotide and the penultimate (N-l) nucleotide in, e.g., the Rp configuration, and / or a backbone phosphoryl guanidine (PN) chiral center comprising the structure of, e.g.,

[0085]

[0086] between, e.g., the penultimate (N-l) nucleotide and the immediately upstream (N-2) nucleotide in, e.g., the Rp configuration. In an exemplary embodiment, the guide strand does not comprise a backbone phosphoryl guanidine (PN) chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide. In an exemplary embodiment, the guide strand does not comprise a backbone phosphoryl guanidine (PN) chiral center between the penultimate (N-l) nucleotide and the immediately upstream (N-2) nucleotide. In an exemplary embodiment, the guide strand comprises a phosphorothioate (PS) chiral center between, e.g., the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide in, e.g., the 5p configuration.

[0087] In a sixth aspect, the invention relates to a double-stranded RNAi (dsRNAi) agent capable of directing target-specific RNA interference, the dsRNAi agent comprising a guide strand and a passenger strand, wherein: the guide strand is complementary or substantially complementary to a target RNA sequence; the guide strand comprises a seed region at its 5’ end region that is capable of mediating the initial recognition of the target RNA sequence, e.g., nucleotides at positions 2-6, at positions 2-7, or at positions 2-8, relative to the 5 ’-end of the guide strand; the guide strand comprises a backbone phosphoryl guanidine (PN) chiral

[0088] center comprising the structure of,

[0089]

[0090] the 5p configuration, in the seed region, e.g., between the third (+3) nucleotide and the immediately downstream (+4) nucleotide, relative to its 5’ terminal nucleotide; wherein the nucleoside 3’ to the PN chiral center in the seed region comprises a 2’-F ribose modification. In an exemplary embodiment, the guide strand further comprises a backbone phosphoryl guanidine (PN)

[0091] chiral center comprising the structure of,

[0092]

[0093] between the +10 nucleotide and the immediately downstream (+11) nucleotide, relative to the 5’ terminal nucleotide of the guide strand. In an exemplary embodiment, the guide strand further comprises a backbone phosphoryl guanidine (PN) chiral center between the +10 nucleotide and the immediately downstream (+11) nucleotide, relative to the 5’ terminal nucleotide ofthe guide strand. In an exemplary embodiment, the nucleoside 3’ to the PN chiral center between the +10 nucleotide and the immediately downstream (+11) nucleotide, relative to the 5’ terminal nucleotide of the guide strand, comprises a 2’-F ribose modification. In an exemplary embodiment, the backbone phosphoryl guanidine (PN) chiral center between the +10 nucleotide and the immediately downstream (+11) nucleotide, relative to the 5’ terminal nucleotide of the guide strand, is in, e.g., the Ap configuration. In an exemplary embodiment, the guide strand further comprises a backbone phosphoryl guanidine (PN) chiral center

[0094] comprising the structure of,

[0095]

[0096] between, e.g., the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide in, e.g., the Rp configuration, and / or a backbone phosphoryl guanidine (PN) chiral center comprising the structure of, e.g.,

[0097]

[0098] between, e.g., the penultimate (N-l) nucleotide and the immediately upstream (N-2) nucleotide in, e.g., the Rp configuration. In an exemplary embodiment, the guide strand does not comprise a backbone phosphoryl guanidine (PN) chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide. In an exemplary embodiment, the guide strand does not comprise a backbone phosphoryl guanidine (PN) chiral center between the penultimate (N-l) nucleotide and the immediately upstream (N-2) nucleotide. In an exemplary embodiment, the guide strand comprises a phosphorothioate (PS) chiral center between, e.g., the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide in, e.g., the 5p configuration. In an exemplary embodiment, the guide strand comprises a 5’ phosphate modification, e.g., a 5’ phosphate mimic modification. In an exemplary embodiment, the 5’ phosphate mimic modification is, e.g.,

[0099]

[0100] , wherein: the base is, e.g., N3U, or is selected from, e.g., A, C, G, T, U, abasic, and modified nucleobases other than N3U; and R1is selected from, e.g., H, OH, O-alkyl, O-methyl (O-Me), F, O-methoxyethyl (MOE), and 2’-(9,4’C-methylene-bridged or locked nucleic acid (2’,4’-BNA or LNA). In an exemplary embodiment, R1is, e.g., O-methyl (O-Me).In particular embodiments of the first, second, third, fourth, fifth, and sixth aspects of the present disclosure, the dsRNAi agent comprises a 5’ phosphate modification. In certain embodiments, the 5’ phosphate modification is a 5’ phosphate mimic modification. In particular embodiments, the 5’ phosphate mimic modification is selected from

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107]

[0108] 10

[0109]

[0110]

[0111]

[0112]

[0113]

[0114] or is selected from, e.g., A, C, G, T, U, abasic, and modified nucleobases other than N3U; R1is selected from, e.g., H, OH, O-alkyl, O-methyl (O-Me), F, O-methoxy ethyl (MOE), and 2’-O,4’C-methylene-bridged or locked nucleic acid (2’,4’-BNA or LNA); R2is selected from alkyl, methyl, ethyl, isopropyl, propyl, cyclohexyl, benzyl, phenyl, tolyl, xylyl, aryl, and arene group; and R6is selected from H, methyl, ethyl, isopropyl, propyl, cyclohexyl, benzyl, phenyl, tolyl, xylyl, aryl, and arene group. In certain embodiments, R1is O-Me. In particular embodiments, the 5’ phosphate mimic modification is O’

[0115] i

[0116] Base

[0117]

[0118] . p, or

[0119] Base

[0120] o^

[0121]

[0122] O R1

[0123] is methyl. In particular embodiments, the guide strand further comprisesa backbone phosphorothioate (PS) chiral center in the Sp configuration between the 5’ terminal (+1) nucleotide and the immediately downstream (+2) nucleotide, and a backbone PS chiral center in the Sp configuration between the +2 nucleotide and immediately downstream (+3) nucleotide.

[0124] In particular embodiments, the guide strand further comprises a backbone phosphorothioate (PS) chiral center in the Sp configuration between the 5’ terminal (+1) nucleotide and the immediately downstream (+2) nucleotide, and wherein the backbone linkage between the +2 nucleotide and the immediately downstream (+3) nucleotide of the guide strand is an unmodified phosphodiester (PO) linkage.

[0125] In accordance with another aspect of the disclosed subject matter, the present disclosure provides a double-stranded RNAi (dsRNAi) agent capable of directing targetspecific RNA interference, the dsRNAi agent comprising a guide strand and a passenger strand, wherein the guide strand is complementary or substantially complementary to a target RNA sequence, wherein the guide strand comprises a 5’ phosphate modification, and wherein the guide strand further comprises a backbone phosphorothioate (PS) chiral center in the Sp configuration between the 5’ terminal (+1) nucleotide and the immediately downstream (+2) nucleotide, and a backbone PS chiral center in the Sp or Rp configuration between the +2 nucleotide and immediately downstream (+3) nucleotide.

[0126] In particular embodiments, the backbone PS chiral center between the +2 nucleotide and immediately downstream (+3) nucleotide is in the Sp configuration. In alternative embodiments, the backbone PS chiral center between the +2 nucleotide and immediately downstream (+3) nucleotide is in the Rp configuration.

[0127] In accordance with another aspect of the disclosed subject matter, the present disclosure provides a double-stranded RNAi (dsRNAi) agent capable of directing targetspecific RNA interference, the dsRNAi agent comprising a guide strand and a passenger strand, wherein the guide strand is complementary or substantially complementary to a target RNA sequence; wherein the guide strand comprises a 5’ phosphate modification; wherein the guide strand further comprises a backbone phosphorothioate (PS) chiral center in the 5p configuration between the 5’ terminal (+1) nucleotide and the immediately downstream (+2) nucleotide; and wherein the backbone linkage between the +2 nucleotide and the immediately downstream (+3) nucleotide of the guide strand is an unmodified phosphodiester (PO) linkage.In particular embodiments, the 5’ phosphate modification is a 5’ phosphate mimic modification. In certain embodiments, the 5’ phosphate mimic modification is selected from:

[0128]

[0129]

[0130]

[0131] the base is selected from A, C, G, T, U, abasic, and modified nucleobases other than N3U;

[0132] R1is selected from H, OH, O-alkyl, O-methyl (O-Me), F, O-methoxyethyl (MOE), and 2’-(9,4’C-methylene-bridged or locked nucleic acid (2’,4’-BNA or LNA); and

[0133] R2is selected from alkyl, methyl, ethyl, isopropyl, propyl, cyclohexyl, benzyl, phenyl, tolyl, xylyl, aryl, and arene group.

[0134] In certain embodiments, the 5’ phosphate mimic modification is

[0135]

[0136] particular embodiments, R1is LNA bridge to the 4’ position. In certain embodiments, R1is MOE. In particular embodiments, R1is F. In certain

[0137]

[0138] phosphate mimic modification

[0139]

[0140] , where the base is U or abasic, R1is H or O-alkyl. In particular embodiments, R1is O-C16 alkyl. In particular embodiments, R6is H.In particular embodiments, the 5’ phosphate mimic modification is

[0141]

[0142] In certain embodiments, the 5’ phosphate mimic modification is

[0143]

[0144] , where the base is abasic and R1is H.

[0145] In particular embodiments, the 5’ phosphate mimic modification is,

[0146]

[0147] the R1is O-Me and R6is H.

[0148] In particular embodiments, the guide strand further comprises a backbone phosphoryl guanidine (PN) chiral center in the Sp configuration between the +3 nucleotide and the immediately downstream (+4) nucleotide. In certain embodiments, the guide strand further comprises backbone PS chiral centers in Sp configuration between the 3’ terminal nucleotide and the penultimate (N-l) nucleotide and between the penultimate (N-l) nucleotide and the immediately upstream (N-2) nucleotide. In particular embodiments, the guide strand comprises an Rp, Sp, or stereorandom non-negatively charged internucleotidic linkage between the tenth (+10) and eleventh (+11) nucleotides, relative to the 5’ terminal nucleotide. In particular embodiments, the guide strand further comprises a backbone PN chiral center between the +10 nucleotide and the +11 nucleotide is in the Rp configuration. In certain embodiments, the guide strand comprises one or more Rp, Sp, or stereorandom non-negatively charged internucleotidic linkage occurs between any two adjacent nucleotides between the second (+2) nucleotide relative to the 5’ terminal nucleotide of the guide strand and the penultimate 3’ (N-l) nucleotide of the guide strand, where N is the 3’terminal nucleotide. In particular embodiments, the guide strand comprises a 2’ modification, of the 3’ nucleotide of a nucleotide pair linked by an Rp, Sp, or stereorandom non-negatively charged internucleotidic linkage. In certain embodiments, the guide strand comprises an Rp, Sp, or stereorandom non-negatively charged internucleotidic linkage between the seventh (+7) and eighth (+8) nucleotides, relative to the 5’ terminal nucleotide. In particular embodiments, the guide strand comprises one or more backbone phosphorothioate chiral centers in Rp or Sp configuration where linkage occurs between any two adjacent nucleotides between the penultimate 3’ nucleotide of the guide strand, where N is the 3’ terminal nucleotide, and the upstream N-10 nucleotide.

[0149] In certain embodiments, the passenger strand comprises one or more Rp, Sp, or stereorandom non-negatively charged internucleotidic linkage occurs upstream, i.e., in the 5’ direction, relative to the central nucleotide of the passenger strand. In particular embodiments, the passenger strand comprises one or more Rp, Sp, or stereorandom non-negatively charged internucleotidic linkage occurs upstream, i.e., in the 5’ direction, relative to the central nucleotide of the passenger strand. In certain embodiments, the passenger strand comprises one or more Rp, Sp, or stereorandom non-negatively charged internucleotidic linkage occurs downstream, i.e., in the 3’ direction, relative to the central nucleotide of the passenger strand. In particular embodiments, the passenger strand comprises one or more backbone phosphorothioate chiral centers in Rp or Sp configuration internucleotidic linkage occurs upstream, i.e., in the 5’ direction, relative to the central nucleotide of the passenger strand. In certain embodiments, the passenger strand in combination with one or more of the aforementioned guide strands, comprises one or more modified sugars between the 5’ terminal (+1) nucleotide and the penultimate (N-l) nucleotide.

[0150] In particular embodiments, the passenger strand comprises one or more of 0-n Rp, Sp, or stereorandom non-negatively charged internucleotidic linkages, where n is about 1 to 49, one or more backbone chiral centers in Rp or Sp configuration, one or more backbone phosphoryl guanidine chiral centers in the Rp configuration between the +7 nucleotide and the immediately downstream (+8) nucleotide, i.e., in the 3’ direction, one or more backbone phosphoryl guanidine chiral centers in the Rp configuration between the +15 nucleotide and the immediately downstream (+16) nucleotide, i.e., in the 3’ direction, and / or backbone phosphorothioate chiral centers in the Sp configuration between the 5’ terminal (+1) nucleotide and the immediately downstream, i.e., in the 3’ direction, (+2) nucleotide and between the 3’ terminal nucleotide and the penultimate (N-l) nucleotide.In particular embodiments, each strand of the dsRNAi agent independently has a length of about 15 to about 49 nucleotides.

[0151] In particular embodiments, the dsRNAi agent of any of the preceding claims, wherein the Rp, Sp, or stereorandom non-negatively charged backbone intemucleotidic linkages have neutral charge. In particular embodiments, the neutral backbone

[0152] intemucleotidic linkage i

[0153]

[0154] , wherein n is about 0 to 49 and m is about 0 to 49.

[0155] In particular embodiments, the guide strand comprises a linkage having the following structure between the third (+3) and fourth (+4) nucleotides of the guide strand, between the tenth (+10) and eleventh (+11) nucleotides of the guide strand, or both.

[0156] In particular embodiments, guide strand comprises a linkage having the following structure

[0157]

[0158] between the third (+3) and fourth (+4) nucleotides of the guide strand, between the seventh (+7) and eighth (+8) nucleotides of the guide strand, between the tenth (+10) and eleventh (+11) nucleotides of the guide strand, between the eighteenth (+18) and nineteenth (+19) nucleotides of the guide strand, or combinations thereof.

[0159] In particular embodiments, the passenger strand comprises a linkage having the

[0160] following structure

[0161]

[0162] about 0 to 49 and m is about 0 to 49, at 5’ to the central nucleotide of the passenger strand, 3’ to the central nucleotide of the passenger strand, or both.

[0163] In particular embodiments, the passenger strand comprises a linkage having thefollowing structure

[0164]

[0165] , wherein n is about 11 to 49 and m is 0, or n is 11 or 15.

[0166] In particular embodiments, the passenger strand comprises a non-negatively charged backbone internucleotidic linkage in the Rp configuration between the +7 nucleotide and the +8 nucleotide, a non-negatively charged backbone internucleotidic linkage in the Rp configuration between the +15 nucleotide and the +16 nucleotide and / or a backbone phosphorothioate chiral centers in the Sp configuration between the 5’ terminal (+1) nucleotide and the +2 nucleotide and between the 3’ terminal nucleotide and the penultimate (N-l) nucleotide.

[0167] In particular embodiments, the passenger strand comprises:

[0168]

[0169] in the Rp configuration between the +7 nucleotide and the +8 nucleotide,

[0170]

[0171] the Rp configuration between the +15 nucleotide and the +16 nucleotide, and a backbone phosphorothioate chiral centers in the Sp configuration between the +1 nucleotide and the +2 nucleotide and between the 3’ terminal nucleotide and the penultimate (N-l) nucleotide.

[0172] In particular embodiments, the passenger strand comprises:

[0173]

[0174] the Rp configuration between the +7 nucleotide and the +8 nucleotide and backbone phosphorothioate chiral centers in the Sp configurationbetween the +1 nucleotide and the +2 nucleotide and between the 3’ terminal nucleotide and the penultimate (N-l) nucleotide.

[0175] In accordance with another aspect of the disclosed subject matter, the present disclosure provides a method for reducing level and / or activity of a transcript or a protein encoded thereby, comprising administering to a cell expressing the transcript a doublestranded RNAi (dsRNAi) agent of any of the above aspects or embodiments.

[0176] In certain embodiments, the cell is an immune cell, a blood cell, a cardiac cell, a lung cell, an optic cell, a muscle cell, a liver cell, a kidney cell, a cell of the central nervous system, or a cell of the peripheral nervous system. In particular embodiments, the cell of the central nervous system is a brain cell. In certain embodiments, when the double-stranded RNAi (dsRNAi) agent is contacted with a cell comprising transcripts of both the target allele and another allele of the same nucleic acid sequence, it shows suppression of transcripts of the particular allele at a level that is greater than when the double-stranded RNAi (dsRNAi) agent is absent, greater than a level of suppression observed for another allele of the same nucleic acid sequence, both greater than when the double-stranded RNAi (dsRNAi) agent is absent, and greater than a level of suppression observed for another allele of the same nucleic acid sequence.

[0177] It is to be understood that both the foregoing general description and the following detailed description are examples and are provided for purpose of illustration and not intended to limit the scope of the disclosed subject matter in any manner.

[0178] I. DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS Technologies of the present disclosure may be understood more readily by reference to the following detailed description of certain embodiments.

[0179] Definitions

[0180] As used herein, the following definitions shall apply unless otherwise indicated. For purposes of this disclosure, the elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75th Ed. Additionally, general principles of organic chemistry are described in " Organic Chemistry", Thomas Sorrell, University Science Books, Sausalito: 1999, and " March's Advanced Organic Chemistry", 5th Ed., Ed.: Smith, M. B. and March, J., John Wiley & Sons, New York: 2001.

[0181] As used herein, the terms “aliphatic”, “alkenyl”, “alkyl”, “alkynyl”, “analog”, “animal”, “aryl”, “chiral control”, “chirally controlled oligonucleotide composition”,“cycloaliphatic,” “heteroaliphatic”, “heteroalkyl”, “heteroaryl”, “heteroatom”, “heterocycle”, “identity”, “internucleotidic linkage”, “in vitro”, “in vivo”, “linkage phosphorus”, “modified nucleobase”, “modified nucleoside”, “modified nucleotide”, “modified sugar”, “nucleic acid”, “nucleobase”, “nucleoside”, “nucleotide”, “oligonucleotide”, “oligonucleotide type”, “substituted”, “optionally substituted”, “stable”, “P-modification”, “partially unsaturated”, “pharmaceutical composition”, “pharmaceutically acceptable”, “pharmaceutically acceptable carrier”, “pharmaceutically acceptable salt”, “predetermined”, “5’ phosphate mimic modification”, “protecting group”, “subject” or “test subject”, “substantially”, “sugar”, “susceptible to”, “therapeutic agent”, “therapeutically effective amount”, “treat,” “treatment,” or “treating”, “unsaturated”, “wildtype”, and the like have their art-understood meaning as would be appreciated by those of ordinary skill in the art, and as specifically defined in WO 2024 / 182749, at pages 147-179, the contents of which are incorporated herein by reference in their entirety.

[0182] 1. Description of Certain Embodiments

[0183] As examples, certain dsRNAi oligonucleotides comprising certain example base sequences, nucleobase modifications and patterns thereof, sugar modifications and patterns thereof, internucleotidic linkages and patterns thereof, linkage phosphorus stereochemistry and patterns thereof, linkers, and / or additional chemical moieties are presented in Table 1 (e.g., Tables IB, 1C, ID, and IE), below. Among other things, ds oligonucleotides, e.g., those in Table 1, may be utilized to target a transcript, e.g., to reduce the level of a transcript and / or a product thereof.Table IB. Example Oligonucleotides / Compositions that target TTR.

[0184]

[0185]

[0186]

[0187]

[0188]

[0189]

[0190]

[0191]

[0192]

[0193]

[0194]

[0195]

[0196]

[0197]

[0198]

[0199]

[0200]

[0201]

[0202]

[0203]

[0204] Table ID. Example Guide Strand Compositions.

[0205]

[0206]

[0207]

[0208]

[0209]

[0210]

[0211] Table IE. Example Passenger Strand Compositions.

[0212]

[0213]

[0214]

[0215]

[0216]

[0217] Table 1F. Example Oligonucleotides / Compositions

[0218]

[0219]

[0220]

[0221]

[0222]

[0223]

[0224]

[0225]

[0226]

[0227]

[0228]

[0229]

[0230] Table 1H. Example Guide Strand Compositions

[0231]

[0232]

[0233]

[0234]

[0235]

[0236]

[0237]

[0238]

[0239]

[0240] Table II. Example Oligonucleotide Compositions

[0241]

[0242]

[0243]

[0244]

[0245]

[0246] Notes:

[0247] HELM notations, due to their length, may be divided into multiple lines in the above tables. As appreciated by those skilled in the art, nucleoside units are unmodified unless otherwise indicated (e.g., with m, [fl2r], etc.); linkages, unless otherwise indicated, are natural phosphate linkages; and acidic / basic groups may independently exist in their salts. If an internucleotidic linkage is not specified, the internucleotidic linkage is a natural phosphate linkage. A natural DNA sugar may also be indicated with “d” as in d(G), d(A), d(C), d(T), etc., and a natural phosphate linkage may be indicated with “p” in Table 1. Oligonucleotides in Table 1 are described using various features of Hierarchical Editing Language for Macromolecules (HELM), which is described in, e.g., Zhang, T. et al. J Chem Inf Model. 2012 Oct 22;52(10):2796-806 and Milton, J. et al. J Chem Inf Model. 2017 Jun 26;57(6): 1233-1239, which are incorporated herein by reference. As described in Zhang et al., 2012 and Milton et al., 2017, connections between oligonucleotides, linker moieties, GalNAc moieties, etc. may be indicated in HELM, for example, as the following: CHEM1, RNA1,1: R1-1: R1, wherein CHEMI is, e.g., a first linker or moiety, RNA1 is an oligonucleotide, and 1: R1-1: R1 indicates that CHEMI is linked via a first attachment point to a first attachment point on a first monomer of RNA1, as described herein (see, e.g., below). A double-stranded oligonucleotide may be indicated in HELM, for example, as the following: RNA1, wherein RNA1 is, e.g., a first oligonucleotide strand of a double-stranded oligonucleotide, and RNA2, wherein RNA2 is, e.g., a second oligonucleotide strand of the double-stranded oligonucleotide.

[0248] Various moieties and modifications (e.g., internucleotidic linkages, sugars, nucleobases, etc.) are described in the present disclosure including the below:

[0249] m: 2’-0Me (sugar is 2'-O-methylribose);

[0250] [fl2r]: 2’-F (sugar is 2’ -fluoro-2’ -deoxyribose);

[0251] PO or p: phosphodiester or phosphate;

[0252] PS or [sp]: phosphorothioate;

[0253] Rp or [Rsp]: phosphorothioate in the Rp configuration;

[0254] Sp or [Ssp]: phosphorothioate in the Sp configuration;

[0255] [sa]: sulfonamide

[0256] [su]: sulfonic acid

[0257] [cp]: capping phosphate

[0258] [tz]: 1H-1,2,3-triazole (1,4 linkage)o

[0259] [ptz]:

[0260]

[0261] , (l / / -l,2,3-triazol-4-yl)phosphonate or 4-phosphono- 1,2, 3 -triazol - 1-yl, bonded to 5 ’-carbon of the 5 ’-end nucleoside;

[0262] [4mtz]: 4-methyl-1H-1,2,3-triazole (1,4 linkage)

[0263] [5tz]: 1H-1,2,3-triazole (1,5 linkage)

[0264] [1m41tz]: 1-methyl-1H-1,2,3-triazole (4-1 linkage)

[0265] [d5hexdec2r]: 2-O-hexadecyl-5-deoxyribose

[0266] [2Sm2pyrl]: (S)-2-methyl pyrrolidine (1-2 linkage)

[0267] [dSp]: 1,2-dideoxyribose (5-3 connectivity)

[0268] [d5m]: 5-deoxy-2-O-methylribose

[0269] [dd5m]: 5-desmethyl-5-deoxy-2-O-methylribose

[0270] [Pyra]: 1H-pyrazole (1-4 linkage)

[0271] [pyrl]: pyrrolidine (1-3 linkage)

[0272] [2pyrl]: pyrrolidine (1-2 linkage)

[0273] [azir]: aziridine (1-2 linkage)

[0274] [vped5m]: 5-(E)-vinylphosphonate-5-deoxy-2-O-methylribose;

[0275] [Zvped5m]: 5-(Z)-vinylphosphonate-5-deoxy-2-methylribose

[0276] [m4Imi]: 4-methyl-1H-imidazol (1-4 linkage)

[0277] [m5Imi]: 5-methyl-1H-imidazol (1-5 linkage)

[0278] [d5unam]: 5-deoxy-2,3-unlocked-2-methoxyribose

[0279]

[0280] -dimethylimidazolidin-2-ylidene)phosphoramidate);

[0281] [nOOlR]: nOOl in Rp configuration;

[0282] [n001S]: n001 in Sp configuration;

[0283]

[0284] -dimethylimidazolidin-2-ylidene)phosphoramidate;

[0285] [n003R]: n003 in Rp configuration;

[0286] [n003S]: n003 in Sp configuration;

[0287]

[0288] [n004R]: n004 in Rp configuration;

[0289] [n004S]: n004 in 5p configuration;

[0290]

[0291] (di(morpholin- 1 -yl)methylene)phosphoramidate;

[0292] [n008R]: n008 in Rp configuration;

[0293] [n008S]: n008 in Sp configuration;

[0294]

[0295] -docecyl-3-methylimidazolidin-2-ylidene)phosphoramidate;

[0296] [n009R]: n009 in Rp configuration;

[0297] [n009S]: n009 in Sp configuration;

[0298]

[0299] -dimethyltetrahydropyrimidin-2(lH)-ylidene)phosphoramidate;

[0300] [n025R]: n025 in Rp configuration;

[0301] [n025S]: n025 in Sp configuration;

[0302]

[0303] [n026R]: n026 in Rp configuration;

[0304] [n026S]: n026 in Sp configuration;

[0305]

[0306] dimethylamino-butyl)-3-methylimidazolidin-2-ylidene)phosphoramidate;

[0307] [n029R]: n029 in Rp configuration;

[0308] [n029S]: n029 in Sp configuration;

[0309]

[0310] -hexyl-3-methylimidazolidin-2-ylidene)phosphoramidate;

[0311] [n031R]: n031 in Rp configuration;

[0312] [n031S]: n031 in Sp configuration;

[0313]

[0314] -hexadecyl-3-methylimidazolidin-2-ylidene)phosphoramidate;

[0315] [n033R]: n033in Rp configuration;

[0316] [n033S]: n033 in Sp configuration;

[0317]

[0318] -dihexylimidazolidin-2-ylidene)phosphoramidate;

[0319] [n037R]: n037in Rp configuration;

[0320] [n037S]: n037 in Sp configuration;

[0321]

[0322] didodecylimidazolidin-2-ylidene)phosphoramidate;

[0323] [n039R]: n039 in Rp configuration;

[0324] [n039S]: n039 in Sp configuration;

[0325]

[0326] -methoxyethyl)imidazolidin-2-ylidene)phosphoramidate;

[0327] [n043R]: n043 in Rp configuration;

[0328] [n043S]: n043 in Sp configuration;

[0329]

[0330] )-pent-2-en-l-yl]imidazolidin-2-ylidene)phosphoramidate;

[0331] [n046R]: n046in Rp configuration;

[0332] [n046S]: n046 in Sp configuration;

[0333]

[0334] -pent-2-en-l-yl]imidazolidin-2-ylidene)phosphoramidate;

[0335] [n047R]: n047in Rp configuration;

[0336] [n047S]: n047 in Sp configuration;

[0337]

[0338] nX: stereorandom n058;

[0339] [n058R]: n058 in Rp configuration;

[0340] [n058S]: n058 in Sp configuration;

[0341]

[0342] -dimethyl-l,3-dihydro-27 / -benzo[d]imidazol-2-ylidene)phosphoramidate;

[0343] [n065R]: n065 in Rp configuration;

[0344] [n065S]: n065 in Sp configuration;

[0345]

[0346] aminopropyl)-3 -methylimidazolidin-2-ylidene)phosphoramidate;

[0347] [n069R]: n069 in Rp configuration;

[0348] [n069S]: n069 in Sp configuration;

[0349]

[0350] benzo[d]imidazol-2ylidene)phosphoramidate;

[0351] [n070R]: n070 in Rp configuration;

[0352] [n070S]: n070 in Sp configuration;

[0353]

[0354] benzo[d]imidazol- 2ylidene)phosphoramidate;

[0355] [n071R]: n071 in Rp configuration;

[0356] [n071S]: n071 in Sp configuration;

[0357]

[0358] pzt-

[0359]

[0360] , wherein “pzt” or “5pzt” corresponds to the triazol ephosphonate moiety, and “d5moe” corresponds to the 5’ -deoxy - 2’-(9-methoxyethyl moiety;

[0361] pzt-

[0362]

[0363] wherein “pzt” or “5pzt‘ corresponds to the triazolephosphonate moiety, and “d5fl2r” corresponds to the 5’ -deoxy -2’ -fluoro moiety;

[0364] pzt-d51r-U or 5pzt-d51r-U

[0365]

[0366] wherein “pzt” or “5pzt” corresponds to the triazolephosphonate moiety, and “d51r” corresponds to the 2’-(,4’C-methylene-bridged or locked nucleic acid (2’,4’-BNA or LNA) moiety;

[0367] pzt-d5m-U or

[0368]

[0369] wherein “pzt” or “5pzt” corresponds to the triazolephosphonate moiety, and “d5m” corresponds to the 5’-deoxy-2’-( -methyl moiety;pzt-

[0370]

[0371] wherein “pzt” or “5pzt” corresponds to the triazol ephosphonate moiety, “d5m” corresponds to the 5 ’-deoxy -2’ -O- methyl moiety, and “3nU” corresponds to the N-3-uridine (N3U) base modification moiety

[0372] having the structure

[0373]

[0374] [GalNAc3C12oyl]: triantennary GalNAc with C12 linker or

[0375]

[0376] [GalNAc3C12oyl][nC6o] conjugated to the 5 ’-end of an oligonucleotide:

[0377]

[0378] , wherein is or represents an oligonucleotide chain.

[0379] [nC6o]: −NH−(CH2)6− linker (C6 linker, C6 amine linker or C6 amino linker), connected to one moiety, e.g., CHEM2 (e.g., [GalNAc3C12oyl]), through -NH- (e.g., forming an amide group -C(O)-NH-), and, in various cases, the 5 ’-end of the oligonucleotide chain through a linkage (e.g., if the 5 ’-end of an oligonucleotide contains p, through a phosphate linkage (the end -CH2- bonded to an oxygen atom which is bonded to linkage phosphorus); if the 5’-end of an oligonucleotide contains [sp], through a phosphorothioate linkage (the end -CH2- bonded to an oxygen atom which is bonded to linkage phosphorus). [nC6o] may also be properly considered as 6-aminohexanol wherein, as indicated, its amino group forms an amide and its hydroxy forms a linkage such as a phosphate linkage.

[0380] Double Stranded Oligonucleotide Lengths

[0381] As appreciated by those skilled in the art, ds oligonucleotides can be of various lengths to provide desired properties and / or activities for various uses. Many technologies for assessing, selecting and / or optimizing ds oligonucleotide length are available in the art and can be utilized in accordance with the present disclosure. As demonstrated herein, in certain embodiments, dsRNAi oligonucleotides are of suitable lengths to hybridize with their targets and reduce levels of their targets and / or an encoded product thereof. In certain embodiments, a ds oligonucleotide is long enough to recognize a target nucleic acid (e.g., a target mRNA). In certain embodiments, a ds oligonucleotide is sufficiently long to distinguish between a target nucleic acid and other nucleic acids (e.g., a nucleic acid having a base sequence which is not a target sequence) to reduce off-target effects. In certain embodiments, a dsRNAi oligonucleotide is sufficiently short to reduce complexity of manufacture or production and to reduce cost of products.

[0382] Internucleotidic LinkagesIn certain embodiments, ds oligonucleotides comprise base modifications, sugar modifications, and / or internucleotidic linkage modifications. Various intemucleotidic linkages can be utilized in accordance with the present disclosure to link units comprising nucleobases, e.g., nucleosides. In certain embodiments, provided ds oligonucleotides comprise both one or more modified internucleotidic linkages and one or more natural phosphate linkages. As widely known by those skilled in the art, natural phosphate linkages are widely found in natural DNA and RNA molecules; they have the structure of -OP(O)(OH)O-, connect sugars in the nucleosides in DNA and RNA, and may be in various salt forms, for example, at physiological pH (about 7.4), natural phosphate linkages are predominantly exist in salt forms with the anion being -OP(O)(O )O- A modified internucleotidic linkage, or a non-natural phosphate linkage, is an internucleotidic linkage that is not natural phosphate linkage or a salt form thereof. Modified internucleotidic linkages, depending on their structures, may also be in their salt forms. For example, as appreciated by those skilled in the art, phosphorothioate internucleotidic linkages which have the structure of-OP(O)(SH)O- may be in various salt forms, e.g., at physiological pH (about 7.4) with the anion being -OP(O)(S )O- Without wishing to be bound by any particular theory, the present disclosure notes that a neutral intemucleotidic linkage can be more hydrophobic than a phosphorothioate internucleotidic linkage (PS), which can be more hydrophobic than a natural phosphate linkage (PO). Typically, unlike a PS or PO, a neutral intemucleotidic linkage bears less charge. Without wishing to be bound by any particular theory, the present disclosure notes that incorporation of one or more neutral internucleotidic linkages into a ds oligonucleotide may increase the ds oligonucleotides’ ability to be taken up by a cell and / or to escape from endosomes. Without wishing to be bound by any particular theory, the present disclosure notes that incorporation of one or more neutral internucleotidic linkages can be utilized to modulate melting temperature of duplexes formed between a ds oligonucleotide and its target nucleic acid.

[0383] Without wishing to be bound by any particular theory, the present disclosure notes that incorporation of one or more non-negatively charged intemucleotidic linkages, e.g., neutral internucleotidic linkages, into a ds oligonucleotide may be able to increase the ds oligonucleotide’s ability to mediate a function such as target adenosine editing.

[0384] In some embodiments, an oligonucleotide comprises a modified internucleotidic linkage (e.g., a modified internucleotidic linkage having the structure of Formula I, I-a, I-b, or I-c, I-n-1, I-n-2, I-n-3, 1-n-4, II, II-a-1, II-a-2, II-b-1, II-b-2, II-c-1, II-c-2, II-d-1, II-d-2, etc., or a salt form thereof) as described in US 9394333, US 9744183, US 9605019, US 9598458, US 9982257, US 10160969, US 10479995, US 2020 / 0056173, US 2018 / 0216107, US 2019 / 0127733, US 10450568, US 2019 / 0077817, US 2019 / 0249173, US 2019 / 0375774, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, and / or WO 2019 / 032612 the internucleotidic linkages (e.g., those of Formula I, I-a, I-b, or I-c, I-n-1, I-n-2, I-n-3, 1-n-4, II, II-a-1, II-a-2, II-b-1, II-b-2, II-c-1, II-c-2, II-d-1, II-d-2, etc.,) of each of which are independently incorporated herein by reference. In some embodiments, a modified internucleotidic linkage is a non-negatively charged internucleotidic linkage. In some embodiments, provided oligonucleotides comprise one or more non-negatively charged internucleotidic linkages. In some embodiments, a non-negatively charged internucleotidic linkage is a positively charged internucleotidic linkage. In some embodiments, a non-negatively charged internucleotidic linkage is a neutral internucleotidic linkage. In some embodiments, the present disclosure provides oligonucleotides comprising one or more neutral internucleotidic linkages. In some embodiments, a non-negatively charged internucleotidic linkage or a neutral internucleotidic linkage (e.g., one of Formula I-n-1, I-n-2, I-n-3, I-n-4, II, II-a-1, II-a-2, II-b-1, II-b-2, II-c-1, II-c-2, II-d-1, II-d-2, etc.) is as described in US 9394333, US 9744183, US 9605019, US 9598458, US 9982257, US 10160969, US 10479995, US 2020 / 0056173, US 2018 / 0216107, US 2019 / 0127733, US 10450568, US 2019 / 0077817, US 2019 / 0249173, US 2019 / 0375774, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, and / or WO 2019 / 032612. In some embodiments, a non-negatively charged internucleotidic linkage or neutral internucleotidic linkage is one of Formula I-n-1, I-n-2, I-n-3, I-n-4, II, II-a-1, II-a-2, II-b-1, II-b-2, II-c-1, II-c-2, II-d-1, II-d-2, etc. as described in WO 2018 / 223056, WO 2019 / 032607, WO 2019 / 075357, WO 2019 / 032607, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, and / or WO 2019 / 032612, such internucleotidic linkages of each of which are independently incorporated herein by reference.

[0385] As appreciated by those skilled in the art, many other types of internucleotidic linkages may be utilized in accordance with the present disclosure, for example, those described in U. S. Pat. Nos. 3,687,808; 4,469,863; 4,476,301; 5,177,195; 5,023,243;5,034,506; 5,166,315; 5,185,444; 5,188,897; 5,214,134; 5,216,141; 5,235,033; 5,264,423; 5,264,564; 5,276,019; 5,278,302; 5,286,717; 5,321,131; 5,399,676; 5,405,938; 5,405,939; 5,434,257; 5,453,496; 5,455,233; 5,466,677; 5,466,677; 5,470,967; 5,476,925; 5,489,677; 5,519,126; 5,536,821; 5,541,307; 5,541,316; 5,550,111; 5,561,225; 5,563,253; 5,571,799; 5,587,361; 5,596,086; 5,602,240; 5,608,046; 5,610,289; 5,618,704; 5,623,070; 5,625,050; 5,633,360; 5,64,562; 5,663,312; 5,677,437; 5,677,439; 6,160,109; 6,239,265; 6,028,188; 6,124,445; 6,169,170; 6,172,209; 6,277,603; 6,326,199; 6,346,614; 6,444,423; 6,531,590; 6,534,639; 6,608,035; 6,683,167; 6,858,715; 6,867,294; 6,878,805; 7,015,315; 7,041,816; 7,273,933; 7,321,029; or RE39464. In certain embodiments, a modified internucleotidic linkage is one described in US 9982257, US 20170037399, US 20180216108, WO 2017192664, WO 2017015575, WO2017062862, WO 2018067973, WO 2017160741, WO 2017192679, WO 2017210647, WO 2018098264, PCT / US 18 / 35687, PCT / US18 / 38835, or PCT / US18 / 51398, the nucleobases, sugars, internucleotidic linkages, chiral auxiliaries / reagents, and technologies for oligonucleotide synthesis (reagents, conditions, cycles, etc.) of each of which is independently incorporated herein by reference.

[0386] In certain embodiments, a ds oligonucleotide comprises one or more internucleotidic linkages that improve one or more pharmaceutical properties and / or activities of the oligonucleotide. It is well documented in the art that certain oligonucleotides are rapidly degraded by nucleases and exhibit poor cellular uptake through the cytoplasmic cell membrane (Poijarvi-Virta et al., Curr. Med. Chem. (2006), 13(28);3441-65; Wagner et al., Med. Res. Rev. (2000), 20(6):417-51; Peyrottes et al., Mini Rev. Med. Chem. (2004), 4(4):395-408; Gosselin et al., (1996), 43(1): 196-208; Bologna et al., (2002), Antisense & Nucleic Acid Drug Development 12:33-41). Vives et al. (Nucleic Acids Research (1999), 27(20):4071-76) reported that tert-butyl SATE pro-oligonucleotides displayed markedly increased cellular penetration compared to the parent oligonucleotide under certain conditions.

[0387] Various types of internucleotidic linkages may be utilized in combination of other structural elements, e.g., sugars, to achieve desired ds oligonucleotide properties and / or activities. For example, the present disclosure routinely utilizes modified internucleotidic linkages and modified sugars, optionally with natural phosphate linkages and natural sugars, in designing ds oligonucleotides. In certain embodiments, the present disclosure provides a ds oligonucleotide comprising one or more modified sugars. In certain embodiments, the present disclosure provides a ds oligonucleotide comprising one or more modified sugarsand one or more modified intemucleotidic linkages, one or more of which are natural phosphate linkages.

[0388] Double Stranded Oligonucleotide Compositions

[0389] Among other things, the present disclosure provides various ds oligonucleotide compositions. In certain embodiments, the present disclosure provides ds oligonucleotide compositions of ds oligonucleotides described herein. In certain embodiments, a ds oligonucleotide composition, e.g., a dsRNAi oligonucleotide composition, comprises a plurality of a ds oligonucleotide described in the present disclosure. In certain embodiments, a ds oligonucleotide composition, e.g., a dsRNAi oligonucleotide composition, is chirally controlled. In certain embodiments, a ds oligonucleotide composition, e.g., a dsRNAi oligonucleotide composition, is not chirally controlled (stereorandom).

[0390] In certain embodiments, the present disclosure encompasses technologies for designing and preparing chirally controlled ds oligonucleotide compositions. In certain embodiments, a chirally controlled ds oligonucleotide composition comprises a controlled / pre-determined (not random as in stereorandom compositions) level of a plurality of ds oligonucleotides, wherein the ds oligonucleotides share the same linkage phosphorus stereochemistry at one or more chiral intemucleotidic linkages (chirally controlled intemucleotidic linkages). In certain embodiments, ds oligonucleotides of a plurality share the same pattern of backbone chiral centers (stereochemistry of linkage phosphorus). In certain embodiments, a pattern of backbone chiral centers is as described in the present disclosure. In certain embodiments, ds oligonucleotides of a plurality share a common constitution. In certain embodiments, they are structurally identical.

[0391] For example, in certain embodiments, the present disclosure provides a ds oligonucleotide composition comprising a plurality of ds oligonucleotides, wherein ds oligonucleotides of the plurality share:

[0392] 1) a common base sequence, and

[0393] 2) the same linkage phosphorus stereochemistry independently at one or more (e.g., about 1-50, 1-40, 1-30, 1-25, 1-20, 1-15, 1-10, 5-50, 5-40, 5-30, 5-25, 5-20, 5-15, 5-10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 or more) chiral intemucleotidic linkages (“chirally controlled intemucleotidic linkages”); wherein level of ds oligonucleotides of the plurality in the composition is non-random (e.g.,controlled / pre- determined as described herein).

[0394] Common patterns of backbone chiral centers, as appreciated by those skilled in the art, comprise at least one Rp or at least one 5p. Certain patterns of backbone chiral centers are illustrated in, e.g., Table 1.

[0395] In certain embodiments, a chirally controlled ds oligonucleotide composition is enriched, relative to a substantially racemic preparation of ds oligonucleotides share the same common base sequence and a common pattern of backbone linkages, for ds oligonucleotides of the particular ds oligonucleotide type.

[0396] In certain embodiments, ds oligonucleotides of a plurality, e.g., a particular ds oligonucleotide type, have a common pattern of backbone phosphorus modifications and a common pattern of nucleoside modifications. In certain embodiments, ds oligonucleotides of a plurality have a common pattern of sugar modifications. In certain embodiments, ds oligonucleotides of a plurality have a common pattern of base modifications. In certain embodiments, ds oligonucleotides of a plurality have a common pattern of nucleoside modifications. In certain embodiments, ds oligonucleotides of a plurality have the same constitution. In certain embodiments, ds oligonucleotides of a plurality are identical. In certain embodiments, ds oligonucleotides of a plurality are of the same ds oligonucleotide (as those skilled in the art will appreciate, such ds oligonucleotides may each independently exist in one of the various forms of the ds oligonucleotide, and may be the same, or different forms of the ds oligonucleotide). In certain embodiments, ds oligonucleotides of a plurality are each independently of the same ds oligonucleotide or a pharmaceutically acceptable salt thereof.

[0397] In certain embodiments, a chirally controlled ds oligonucleotide composition is chirally pure (or stereopure, stereochemically pure) ds oligonucleotide composition, wherein the ds oligonucleotide composition comprises a plurality of ds oligonucleotides, wherein the ds oligonucleotides are independently of the same stereoisomer (including that each chiral element of the ds oligonucleotides, including each chiral linkage phosphorus, is independently defined (stereodefined)). A chirally pure (or stereopure, stereochemically pure) ds oligonucleotide composition of a ds oligonucleotide stereoisomer does not contain other stereoisomers (as appreciated by those skilled in the art, one or more unintended stereoisomers may exist as impurities from, e.g., preparation, storage, etc.).

[0398] SugarsVarious sugars, including modified sugars, can be utilized in accordance with the present disclosure. In certain embodiments, the present disclosure provides sugar modifications and patterns thereof optionally in combination with other structural elements (e.g., intemucleotidic linkage modifications and patterns thereof, pattern of backbone chiral centers thereof, etc.) that when incorporated into oligonucleotides can provide improved properties and / or activities.

[0399] The most common naturally occurring nucleosides comprise ribose sugars (e.g., in RNA) or deoxyribose sugars (e.g., in DNA) linked to the nucleobases adenosine (A), cytosine (C), guanine (G), thymine (T) or uracil (U). In certain embodiments, a sugar, e.g., various sugars in many oligonucleotides in Table 1 (unless otherwise notes), is a natural DNA sugar (in DNA nucleic acids or oligonucleotides, having the structure of

[0400]

[0401] , wherein a nucleobase is attached to the 1’ position, and the 3’ and 5’ positions are connected to intemucleotidic linkages (as appreciated by those skilled in the art, if at the 5 ’-end of a ds oligonucleotide, the 5’ position may be connected to a 5 ’-end group (e.g., -OH), and if at the 3 ’-end of a ds oligonucleotide, the 3’ position may be connected to a 3 ’-end group (e.g., -OH). In certain embodiments, a sugar is a natural RNA

[0402] sugar (in RNA nucleic acids or oligonucleotides, having the structure

[0403]

[0404] wherein a nucleobase is attached to the 1 ’ position, and the 3 ’ and 5 ’ positions are connected to intemucleotidic linkages (as appreciated by those skilled in the art, if at the 5 ’-end of a ds oligonucleotide, the 5’ position may be connected to a 5 ’-end group (e.g., -OH), and if at the 3 ’-end of a ds oligonucleotide, the 3’ position may be connected to a 3 ’-end group (e.g., -OH). In certain embodiments, a sugar is a modified sugar in that it is not a natural DNA sugar or a natural RNA sugar. Among other things, modified sugars may provide improved stability. In certain embodiments, modified sugars can be utilized to alter and / or optimize one or more hybridization characteristics. In certain embodiments, modified sugars can be utilized to alter and / or optimize target recognition. In certain embodiments, modified sugars can be utilized to optimize Tm. In certain embodiments, modified sugars can be utilized to improve oligonucleotide activities.

[0405] Sugars can be bonded to intemucleotidic linkages at various positions. As nonlimiting examples, intemucleotidic linkages can be bonded to the 2’, 3’, 4’ or 5’ positionsof sugars. In certain embodiments, as most commonly in natural nucleic acids, an internucleotidic linkage connects with one sugar at the 5’ position and another sugar at the 3’ position unless otherwise indicated.

[0406] In certain embodiments, a sugar is an optionally substituted natural DNA or RNA

[0407] sugar. In certain embodiments, a sugar is optionally substituted

[0408]

[0409] In certain embodiments, the 2’ position is optionally substituted. In certain embodiments, a sugar is

[0410] In certain embodiments, a sugar has the structure

[0411]

[0412]

[0413] , wherein each of Rls, R2s, R3s, R4s, and R5sis independently -H, a suitable substituent or suitable sugar modification (e.g., those described in US 9394333, US 9744183, US 9605019, US 9982257, US 20170037399, US 20180216108, US 20180216107, US 9598458, WO 2017 / 062862, WO 2018 / 067973, WO 2017 / 160741, WO 2017 / 192679, WO 2017 / 210647, WO 2018 / 098264, WO 2018 / 022473, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO2019 / 032612, WO 2019 / 055951, and / or WO 2019 / 075357, the substituents, sugar modifications, descriptions of Rls, R2s, R3s, R4s, and R5s, and modified sugars of each of which are independently incorporated herein by reference). In certain embodiments, a sugar

[0414] has the structure

[0415]

[0416] In certain embodiments, R4sis -H. In certain

[0417] embodiments, a sugar has the structure

[0418]

[0419] wherein R2sis -H, halogen, or -OR, wherein R is optionally substituted Ci-6 aliphatic. In certain embodiments, R2sis -H. In certain embodiments, R2sis -F. In certain embodiments, R2sis -OMe. In certain embodiments, R2sis −OCH2CH2OMe.Various additional sugars useful for preparing oligonucleotides or analogs thereof are known in the art and may be utilized in accordance with the present disclosure.

[0420] Nucleobases

[0421] Various nucleobases may be utilized in provided ds oligonucleotides in accordance with the present disclosure. In certain embodiments, a nucleobase is a natural nucleobase, the most commonly occurring ones being A, T, C, G and U. In certain embodiments, a nucleobase is a modified nucleobase in that it is not A, T, C, G or U. In certain embodiments, a nucleobase is optionally substituted A, T, C, G or U, or a substituted tautomer of A T, C, G or U. In certain embodiments, a nucleobase is optionally substituted A, T, C, G or U, e.g., 5mC, 5- hydroxymethyl C, etc. In certain embodiments, a nucleobase is alkylsubstituted A, T, C, G or U. In certain embodiments, a nucleobase is A. In certain embodiments, a nucleobase is T. In certain embodiments, a nucleobase is C. In certain embodiments, a nucleobase is G. In certain embodiments, a nucleobase is U. In certain embodiments, a nucleobase is 5mC. In certain embodiments, a nucleobase is substituted A, T, C, G or U. In certain embodiments, a nucleobase is a substituted tautomer of A, T, C, G or U. In certain embodiments, substitution protects certain functional groups in nucleobases to minimize undesired reactions during oligonucleotide synthesis. Suitable technologies for nucleobase protection in oligonucleotide synthesis are widely known in the art and may be utilized in accordance with the present disclosure. In certain embodiments, modified nucleobases improves properties and / or activities of ds oligonucleotides. For example, in many cases, 5mC may be utilized in place of C to modulate certain undesired biological effects, e.g., immune responses. In certain embodiments, when determining sequence identity, a substituted nucleobase having the same hydrogen- bonding pattern is treated as the same as the unsubstituted nucleobase, e.g., 5mC may be treated the same as C [e.g., a ds oligonucleotide having 5mC in place of C (e.g., AT5mCG) is considered to have the same base sequence as a ds oligonucleotide having C at the corresponding location(s) (e.g., ATCG)].

[0422] In certain embodiments, a modified nucleobase is a modified nucleobase known in the art, e.g., WO2017 / 210647. In certain embodiments, modified nucleobases are expanded-size nucleobases in which one or more aryl and / or heteroaryl rings, such as phenyl rings, have been added.In certain embodiments, a nucleobase is one described in US 9394333, US 9744183, US 9605019, US 9598458, US 9982257, US 10160969, US 10479995, US 2020 / 0056173, US 2018 / 0216107, US 2019 / 0127733, US 10450568, US 2019 / 0077817, US 2019 / 0249173, US 2019 / 0375774, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, and / or WO 2019 / 032612, the nucleobases of each of which is incorporated herein by reference.

[0423] Additional Chemical Moieties

[0424] In certain embodiments, a ds oligonucleotide comprises one or more additional chemical moieties. Various additional chemical moieties, e.g., targeting moieties, carbohydrate moieties, lipid moieties, etc. are known in the art and can be utilized in accordance with the present disclosure to modulate properties and / or activities of provided oligonucleotides, e.g., stability, half-life, activities, delivery, pharmacodynamics properties, pharmacokinetic properties, etc. In certain embodiments, certain additional chemical moieties facilitate delivery of oligonucleotides to desired cells, tissues and / or organs, including but not limited the cells of the central nervous system. In certain embodiments, certain additional chemical moieties facilitate internalization of oligonucleotides. In certain embodiments, certain additional chemical moieties increase oligonucleotide stability. In certain embodiments, the present disclosure provides technologies for incorporating various additional chemical moieties into oligonucleotides.

[0425] In certain embodiments, a ds oligonucleotide comprises an additional chemical moiety demonstrates increased delivery to and / or activity in a tissue compared to a reference oligonucleotide, e.g., a reference oligonucleotide which does not have the additional chemical moiety but is otherwise identical.

[0426] In certain embodiments, non-limiting examples of additional chemical moieties include carbohydrate moieties, targeting moieties, etc., which, when incorporated into oligonucleotides, can improve one or more properties. In certain embodiments, an additional chemical moiety is selected from: glucose, GluNAc (N-acetyl amine glucosamine) and anisamide moieties. In certain embodiments, a provided ds oligonucleotide can comprise two or more additional chemical moieties, wherein the additional chemical moieties are identical or non-identical, or are of the same category (e.g., carbohydrate moiety, sugar moiety, targeting moiety, etc.) or not of the same category.In certain embodiments, an additional chemical moiety is a targeting moiety. In certain embodiments, an additional chemical moiety is or comprises a carbohydrate moiety. In certain embodiments, an additional chemical moiety is or comprises a lipid moiety. In certain embodiments, an additional chemical moiety is or comprises a ligand moiety for, e.g., cell receptors such as a sigma receptor, an asialoglycoprotein receptor, etc. In certain embodiments, a ligand moiety is or comprises an anisamide moiety, which may be a ligand moiety for a sigma receptor. In certain embodiments, a ligand moiety is or comprises a GalNAc moiety, which may be a ligand moiety for an asialoglycoprotein receptor. In certain embodiments, an additional chemical moiety facilitates delivery to liver.

[0427] In certain embodiments, a provided ds oligonucleotide can comprise one or more linkers and additional chemical moieties (e.g., targeting moieties), and / or can be chirally controlled or not chirally controlled, and / or have a bases sequence and / or one or more modifications and / or formats as described herein.

[0428] Various linkers, carbohydrate moieties and targeting moieties, including many known in the art, can be utilized in accordance with the present disclosure. In certain embodiments, a carbohydrate moiety is a targeting moiety. In certain embodiments, a targeting moiety is a carbohydrate moiety.

[0429] Certain additional chemical moieties (e.g., lipid moieties, targeting moieties, carbohydrate moieties), and various linkers for connecting additional chemical moieties to ds oligonucleotide chains, are described in WO 2017 / 062862, WO 2018 / 067973, WO 2017 / 160741, WO 2017 / 192679, WO 2017 / 210647, WO 2018 / 098264, WO 2018 / 022473, WO 2018 / 223056, WO 2018 / 223073, WO 2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO2019032612, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, and / or WO 2019 / 032612, the additional chemical moieties and linkers of each of which are independently incorporated herein by reference, and can be utilized in accordance with the present disclosure. In certain embodiments, an additional chemical moiety is digoxigenin or biotin or a derivative thereof.

[0430] In certain embodiments, an additional chemical moiety is one described in WO 2012 / 030683. In certain embodiments, a provided ds oligonucleotide comprise a chemical structure (e.g., a linker, lipid, solubilizing group, and / or targeting ligand) described in WO 2012 / 030683.

[0431] In certain embodiments, a provided ds oligonucleotide comprises an additional chemical moiety and / or a modification (e.g., of nucleobase, sugar, internucleotidic linkage,etc.) described in: U. S. Pat. Nos. 5,688,941; 6,294,664; 6,320,017; 6,576,752; 5,258,506; 5,591,584; 4,958,013; 5,082,830; 5,118,802; 5,138,045; 6,783,931; 5,254,469; 5,414,077; 5,486,603; 5,112,963; 5,599,928; 6,900,297; 5,214,136; 5,109,124; 5,512,439; 4,667,025; 5,525,465; 5,514,785; 5,565,552; 5,541,313; 5,545,730; 4,835,263; 4,876,335; 5,578,717; 5,580,731; 5,451,463; 5,510,475; 4,904,582; 5,082,830; 4,762,779; 4,789,737; 4,824,941; 4,828,979; 5,595,726; 5,214,136; 5,245,022; 5,317,098; 5,371,241; 5,391,723; 4,948,882; 5,218,105; 5,112,963; 5,567,810; 5,574,142; 5,578,718; 5,608,046; 4,587,044; 4,605,735; 5,585,481; 5,292,873; 5,552,538; 5,512,667; 5,597,696; 5,599,923; 7,037,646; 5,587,371; 5,416,203; 5,262,536; 5,272,250; or 8,106,022.

[0432] In certain embodiments, an additional chemical moiety, e.g., a Mod, is connected via a linker. Various linkers are available in the art and may be utilized in accordance with the present disclosure, for example, those utilized for conjugation of various moieties with proteins (e.g., with antibodies to form antibody-drug conjugates), nucleic acids, etc. Certain useful linkers are described in US 9982257, US 20170037399, US 20180216108, US 20180216107, US 9598458, WO 2017 / 062862, WO 2018 / 067973, WO 2017 / 160741, WO 2017 / 192679, WO 2017 / 210647, WO 2018 / 098264, WO 2018 / 223056, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, and / or WO 2019 / 032612, the linker moieties of each which are independently incorporated herein by reference.

[0433] Pharmaceutical Compositions

[0434] When used as therapeutics, a provided ds oligonucleotide, e.g., a dsRNAi oligonucleotide, or ds oligonucleotide composition thereof is typically administered as a pharmaceutical composition. In certain embodiments, the present disclosure provides pharmaceutical compositions comprising a provided compound, e.g., a ds oligonucleotide, or a pharmaceutically acceptable salt thereof, and a pharmaceutical carrier. In certain embodiments, for therapeutic and clinical purposes, ds oligonucleotides of the present disclosure are provided as pharmaceutical compositions. As appreciated by those skilled in the art, ds oligonucleotides of the present disclosure can be provided in their acid, base or salt forms. In certain embodiments, ds oligonucleotides can be in acid forms, e.g., for natural phosphate linkages, in the form of -OP(O)(OH)O-; for phosphorothioate internucleotidic linkages, in the form of -OP(O)(SH)O-; etc. In certain embodiments, dsRNAi oligonucleotides can be in salt forms, e.g., for natural phosphate linkages, in theform of -OP(O)(ONa)O- in sodium salts; for phosphorothioate internucleotidic linkages, in the form of -OP(O)(SNa)O- in sodium salts; etc. Unless otherwise noted, ds oligonucleotides of the present disclosure can exist in acid, base and / or salt forms.

[0435] In certain embodiments, the present disclosure provides salts of ds oligonucleotides and pharmaceutical compositions thereof. In certain embodiments, a salt is a pharmaceutically acceptable salt. In certain embodiments, a pharmaceutical composition comprises a ds oligonucleotide, optionally in its salt form, and a sodium salt. In certain embodiments, a pharmaceutical composition comprises a ds oligonucleotide, optionally in its salt form, and sodium chloride. In certain embodiments, each hydrogen ion of a ds oligonucleotide that may be donated to a base (e.g., under conditions of an aqueous solution, a pharmaceutical composition, etc.) is replaced by a non-H+cation. For example, in certain embodiments, a pharmaceutically acceptable salt of a ds oligonucleotide is an all-metal ion salt, wherein each hydrogen ion (for example, of -OH, -SH, etc.) of each internucleotidic linkage (e.g., a natural phosphate linkage, a phosphoryl guanidine internucleotidic linkage, a phosphorothioate internucleotidic linkage, etc.) is replaced by a metal ion. Various suitable metal salts for pharmaceutical compositions are widely known in the art and can be utilized in accordance with the present disclosure. In certain embodiments, a pharmaceutically acceptable salt is a sodium salt. In certain embodiments, a pharmaceutically acceptable salt is magnesium salt. In certain embodiments, a pharmaceutically acceptable salt is a calcium salt. In certain embodiments, a pharmaceutically acceptable salt is a potassium salt. In certain embodiments, a pharmaceutically acceptable salt is an ammonium salt (cation N(R)4+). In certain embodiments, a pharmaceutically acceptable salt comprises one and no more than one types of cation. In certain embodiments, a pharmaceutically acceptable salt comprises two or more types of cation. In certain embodiments, a cation is Li+, Na+, K+, Mg2+or Ca2+. In certain embodiments, a pharmaceutically acceptable salt is an all-sodium salt. In certain embodiments, a pharmaceutically acceptable salt is an all-sodium salt, wherein each internucleotidic linkage which is a natural phosphate linkage (acid form -O-P(O)(OH)-O-), if any, exists as its sodium salt form (-O-P(O)(ONa)-O-), and each internucleotidic linkage which is a phosphorothioate or a phosphoryl guanidine internucleotidic linkage (acid form -O-P(O)(SH)-O-), if any, exists as its sodium salt form (-O-P(O)(SNa)-O-).In certain embodiments, dsRNAi oligonucleotides are formulated in pharmaceutical compositions described in WO 2005 / 060697, WO 2011 / 076807 or WO 2014 / 136086.

[0436] In certain embodiments, a composition comprising a ds oligonucleotide is lyophilized. In certain embodiments, a composition comprising a ds oligonucleotide is lyophilized, and the lyophilized ds oligonucleotide is in a vial. In certain embodiments, the vial is back filled with nitrogen. In certain embodiments, the lyophilized ds oligonucleotide composition is reconstituted prior to administration. In certain embodiments, the lyophilized ds oligonucleotide composition is reconstituted with a sodium chloride solution prior to administration. In certain embodiments, the lyophilized ds oligonucleotide composition is reconstituted with a 0.9% sodium chloride solution prior to administration. In certain embodiments, reconstitution occurs at the clinical site for administration. In certain embodiments, in a lyophilized composition, a ds oligonucleotide composition is chirally controlled or comprises at least one chirally controlled internucleotidic linkage and / or the ds oligonucleotide targets.

[0437] II. EXEMPLIFICATION

[0438] Various technologies can be utilized to assess properties and / or activities of provided oligonucleotides and compositions thereof. Some such technologies are described in this Example. Those skilled in the art appreciate that many other technologies can be readily utilized. As demonstrated herein, provided oligonucleotides and compositions, among other things, can be highly active, e.g., in reducing levels of their target nucleic acids.

[0439] Certain examples of provided technologies (compounds (oligonucleotides, reagents, etc.), compositions, methods (methods of preparation, use, assessment, etc.), etc.) were presented herein.

[0440] EXAMPLE 1. Oligonucleotide Synthesis

[0441] Various technologies for preparing oligonucleotides and oligonucleotide compositions (both stereorandom and chirally controlled) can be utilized in accordance with the present disclosure, including, for example, methods and reagents described in U. S.

[0442] 9,394,333, U. S. 9,744,183, U. S. 9,605,019, U. S. 9,598,458, U. S. 9,982,257, U. S.

[0443] 10,160,969, U. S. 10,479,995, U. S. 2020 / 0056173, U. S. 2018 / 0216107, U. S. 2019 / 0127733, U. S. 10,450,568, U. S. 2019 / 0077817, U. S. 2019 / 0249173, U. S. 2019 / 0375774, U. S.

[0444] 2017 / 0037399, U. S. 2018 / 0216108, WO 2018 / 223056, WO 2018 / 223073, WO2018 / 223081, WO 2018 / 237194, WO 2019 / 032607, WO 2019 / 055951, WO 2019 / 075357, WO 2019 / 200185, WO 2019 / 217784, WO 2019 / 032612, WO 2020 / 191252, WO 2021 / 071858, WO 2017 / 062862, WO 2018 / 067973, WO 2017 / 160741, WO 2017 / 192679, WO 2017 / 210647, WO 2018 / 098264, WO 2022 / 099159, and / or W02023 / 201095. The methods and reagents of each of which are incorporated herein by reference. Stereorandom and chirally controlled guide strand sequences were prepared utilizing the synthetic procedures as exemplified in above mentioned disclosures. Respective passenger strands were designed to have covalently linked GalNAc moiety as delivery vehicle at either end of sequences. Oligonucleotides with 5’-GalNAc modifications were synthesized by coupling C6-amino modifier linker at the 5 ’-end of sequence. Oligonucleotides with 3 ’-GalNAc moiety as delivery vehicle were synthesized by utilizing 3’ -C6 amino modified support. The single strand was cleaved from CPG by using deprotection condition as exemplified in earlier disclosures. The resulting amino group containing crude oligonucleotide was purified by ion exchange chromatography on AKTA pure system using a sodium chloride gradient. Desired product was desalted and further used for conjugation with GalNAc acid. After conjugation reaction was found to be complete the material was further purified by ion exchange chromatography and desalted to achieve desired material. For introduction of PN linkages in guide and passenger strands, specific PN coupling cycles were introduced at desired positions in oligonucleotide sequence utilizing the conditions as exemplified in WO2019 / 200185.

[0445] In certain embodiments, oligonucleotides were prepared using suitable chiral auxiliaries, e.g., DPSE and PSM chiral auxiliaries. Various oligonucleotides, e.g., those in Table li, and compositions thereof, were prepared in accordance with the present disclosure.

[0446] Various technologies can be utilized to assess properties and / or activities of provided oligonucleotides and compositions thereof. Some such technologies are described in this Example. Those skilled in the art appreciate that many other technologies can be readily utilized. As demonstrated herein, provided oligonucleotides and compositions, among other things, can be highly active, e.g., in reducing levels of their target nucleic acids.

[0447] Abbreviation

[0448] 1X reagent: TEA-3HF: TEA: H2O: DMSO = 5.0: 1.8: 15.5: 77.7 (v / v / v / v)

[0449] Ac2O: acetic anhydride

[0450] ACN: acetonitrile

[0451] ADIH: 2-azido-l,3-dimethylimidazolium hexafluorophosphateCMIMT: N-cyanomethylimidazolium triflate

[0452] CPG: controlled pore glass

[0453] DCM: dichloromethane, CH2Cl2

[0454] DIPEA: diisopropylethylamine

[0455] DMF: dimethylformamide

[0456] DMSO: dimethylsulfoxide

[0457] DMTr: 4,4'-dimethoxytrityl

[0458] DS1 reagent: TEA-3HF: TEA: H2O: DMSO = 5.0: 7.0: 14.7: 73.3 (v / v / v / v) ETT: 5-(ethylthio)-lH-tetrazole

[0459] GalNAc: N-acetylgalactosamine

[0460] HF: hydrogen fluoride

[0461] HATU: 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate

[0462] IBN: isobutyronitrile

[0463] MeCN: acetonitrile

[0464] MeIm: N-methylimidazole

[0465] PC: propylene carbonate

[0466] TCA: trichloroacetic acid

[0467] TEA: triethylamine

[0468] TEA-3HF: triethylamine trihydrofluoride

[0469] THF: tetrahydrofuran

[0470] TMSI: Trimethylsilyl iodide

[0471] XH: xanthane hydride

[0472] General procedure for the synthesis of chiral-oligos (25 umol scale):

[0473] The automated solid-phase synthesis of chiral-oligos was performed according to the cycles shown in Table 2 (regular amidite cycle, for PO linkages), Table 3 (regular amidite cycle, for stereo-random PS linkages), Table 4 (DPSE amidite cycle, for chiral PS linkages), and Table 5 (PSM amidite cycle, for chiral PN linkages).

[0474] Table 2. Regular Amidite Synthetic Cycle for PO linkages

[0475]

[0476]

[0477] Table 3. Regular Amidite Synthetic Cycle for stereo-random PS linkages

[0478]

[0479] Table 4. DPSE Amidite Synthetic Cycle for chiral PS linkages

[0480]

[0481] Table 5. PSM Amidite Synthetic Cycle for chiral PN linkages

[0482]

[0483]

[0484] In some embodiments, preparations include one or more DPSE and / or PSM cycles

[0485] General procedure for the C& D conditions (25 umol scale}:

[0486] After completion of the synthesis, the CPG solid support was dried and transferred into 50 mL plastic tube. The CPG was treated with IX reagent (2.5 mL; 100 µL / umol) for 3 h at 28°C, then added cone. NH3 (5.0 mL; 200 µL / umol) for 24 h at 37°C. The reaction mixture was cooled to room temperature and the CPG was separated by membrane filtration, washed with 15 mL of H₂O. The crude material (filtrate) was analyzed by LTQ and RP-UPLC.

[0487] General procedure for the purification conditions:

[0488] The crude sense and antisense strands were purified separately by AEX chromatography. The purification run was performed using sodium hydroxide eluents. A sodium chloride gradient was used to elute the oligonucleotide from the column. The elution profile was monitored by UV spectrophotometry, and the selected fraction pool (sense or antisense strand) was then concentrated and diafiltered against purified water to remove the purification buffer by TFF. The UF / DF process proceeded as follows, the selected pool of fractions was neutralized with sodium phosphate monobasic solution and then concentrated to a target concentration. The concentrated oligonucleotide was diafiltered against purified water before final concentration to the target concentration and collected.

[0489] General procedure for the annealing to form duplex:

[0490] The duplex was formed by combining equal molar quantities of the sense and antisense strands with mixing in an appropriately sized vessel. The formation of the duplex was confirmed by UPLC that there was no excess of single strands. The duplex oligonucleotide solution was filtered through a 0.2-micron filter and then placed in freeze drying tray for lyophilization. After lyophilization, the duplex was isolated as a white to off-white solid powder. The resulting duplexes were then analyzed by LTQ / SQ D-MS and reverse phase UPLC. The observed molecular weight of the guide and passenger strands are shown in Table II.

[0491]

[0492] Into a plastic tube, tri-GalNAc (2.0 eq.), HATU (1.9 eq.), and DIPEA (10 eq.) were dissolved in anhydrous MeCN (0.5 mL). The mixture was stirred for 10 min at room temperature, then the mixture was added into the amino-oligo (1 µmol) in H₂O (1 mL) and stirred for 1 h at 37 °C. The reaction was monitored by LC-MS and RP-UPLC. After the reaction was completed, the resultant GalN Ac-conjugated oligo was treated with cone. NH3 (2 mL) for 1 h at 37 °C. The solution was concentrated under vacuum to remove MeCN and cone. NH3. The residue was then dissolved in H₂O (10 mL) for reversed phase purification.

[0493] While various embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and / or structures for performing the functions and / or obtaining the results and / or one or more of the advantages described in the present disclosure, and each of such variations and / or modifications is deemed to be included. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be example and that the actual parameters, dimensions, materials, and / or configurations may depend upon the specific application or applications for which the teachings of the present disclosure is / are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the embodiments of the present disclosure. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, claimed technologies may be practiced otherwise than as specifically described and claimed. In addition, any combination of two or more features, systems, articles, materials, kits, and / or methods, if such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent, is included within the scope of the present disclosure.

[0494] General procedure for the 5 ’-Ethyl phosphonate / 5 ’Methyl Phosphonate- deprotection conditions (25 umole):

[0495] To prepare TMSI solution for 5’-ethyl / methyl phosphonate deprotection, pyridine (0.5 mL) was added to DCM (23.9 mL) and the resulting solution was cooled in ice-bath for 15 minutes. After that TMSI reagent (0.6 mL) was added to the mixture to get a bright yellow solution (total volume 25.0 mL). TMSI quenching solution (50 mL) was prepared by adding 2-Dodecane thiol (12.0 mL) and TEA (18.0 mL) in acetonitrile (18.0 mL).After completion of the synthesis, the CPG solid support was dried and transferred into 50 mL plastic tube. Minimum amount of DCM was added to 5’-ethyl / methyl Phosphonate containing oligonucleotide on CPG and the CPG was vortexed to get a homogenous slurry. To this homogenous slurry, the TMSI solution (10.0 mL) was added slowly and mixed well. After the addition of the total TMSI solution the color of the reaction mixture turns yellow indicating excess of TMSI solution. The resulting reaction mixture was stirred for 30 minutes at room temperature. After 30 min. the support was promptly washed using excess of acetonitrile followed by addition of quenching solution (10.0 mL; 0.4 mL quenching / umole of CPG solid support) and this process was repeated three times (Total quenching volume 30.0 mL). The total exposure time was limited to 20 min. The CPG was rinsed thoroughly using acetonitrile and drying under vacuum. Afterwards, CPG was subjected to standard cleavage and deprotection (C& D) conditions.

[0496] General procedure for the C& D conditions (25 umol scale):

[0497] After completion of the synthesis and 5 ’-phosphonate deprotection, the CPG solid support was dried and transferred into 50 mL plastic tube. The CPG was treated with DS1 reagent (2.5 mL; 100 uL / umol) for 3 h at 27 °C, then added cone. NH3 (5.0 mL; 200 umol / umol) for 24 h at 37 °C. The reaction mixture was cooled to room temperature and the CPG was separated by membrane filtration, washed with 15 mL of H₂O. The crude material (filtrate) was analyzed by LTQ and RP-UPLC.

[0498] General deprotection procedure for the 5 ’-POM protected Triazole Phosphonate:

[0499] No additional steps required after synthesis. POM group (pivolyloxy methyl) can be easily cleaved with the treatment of Ammonium hydroxide during standard cleavage and base deprotection step as mentioned above.

[0500] General deprotection procedure for the 5’-Boronic acid protected Triazole Phosphonate:

[0501] Tetramethyl-dioxaborolan protection (i.e. acetal protection) of boronic acid can be cleaved with final detritylation step (3% DCA in Toluene) of oligo synthesis. After that the sequence undergoes standard cleavage (DS1) and base deprotection step as mentioned above.

[0502] Example 1A. Example alternative procedure for preparation of oligonucleotidecompositions (general cycle)

[0503]

[0504]

[0505] Each B is independently a nucleobase such as BA described herein (e.g., A, C, G, T, U, etc.). Each BPROis independently an optionally protected nucleobase such as BA described herein (e.g., Abz, Cac, Gibu, T, U, etc. suitable for oligonucleotide synthesis). As shown, various linkages can be constructed to connect monomers to nucleosides or oligonucleotides including those on solid support. As appreciate by those skilled in the art these cycles can be utilized to couple monomers to -OH of various other types of sugars.

[0506] In some embodiments, preparations include one or more DPSE and / or PSM cycles. A number of oligonucleotide compositions were synthesized and assessed, including, e.g., those in the Figures and Tables.

[0507] As described and confirmed herein, technologies of the present disclosure are useful for preparing various compositions of oligonucleotides comprising various structural features at various scales (e.g., 1 umol, 5 umol, or 50 umol). It is understood that certain parameters will be modified based on the scale, e.g., volumes or equivalents. In some embodiments, as confirmed herein, provided technologies, e.g., those utilizing chiral auxiliaries comprising electron-withdrawing groups (e.g., RC11comprising electronwithdrawing groups (e.g., −SO₂RC1, −C(O)RC1, etc.)) are particularly useful for preparing chirally controlled compositions of oligonucleotides comprising 2’-OH sugars (e.g., sugars with R2s= OH, such as sugars typically found in natural RNA), particularly when such sugars are bonded to chirally controlled internucleotidic linkages.

[0508] The resulting oligonucleotides can undergo an annealing step to form a duplex.Example IB. Example procedure for preparation of oligonucleotide compositions (1 jimol scale)

[0509] Certain stereopure oligonucleotides were synthesized at 1 pmol scale using a MerMadel92 synthesizer and universal CPG. In some embodiments, an amidite approach was used to incorporate GalNAc on the 5’ end. Generally, cyanoethyl amidites were used to prepare the PO linkages, DPSE amidites for the PS linkages, and PSM amidites for the PN linkages. A typical MerMadel92, 1 pmol cycle is outlined in the table below:

[0510]

[0511] The cycles were performed multiple times until the desired length was achieved.

[0512] The first step of deprotection was performed on the synthesizer. 200 µL of 20% diethylamine in ACN was added to the column for 3 x 6 min followed by washing with ACN and drying. CPG was transferred to a container and 250 µL of fluoride solution was added. The fluoride solution consisted of dimethylformamide, water, triethylamine trihydrofluoride, and triethylamine (15.5 / 3.1 / 1.0 / 1.8 volume ratio). After about 4 hours at room temperature, approximately 375 µL of 30% ammonium hydroxide was added, and the reaction incubated at 37 °C overnight. The CPG was filtered and washed with water and the filtrate collected.

[0513] The oligonucleotides were purified by anion exchange purification at room temperature. The oligonucleotide was loaded onto a column packed with Source Q15 resin after equilibration with a 20 mM sodium hydroxide in 20% acetonitrile mobile phase. The purified oligonucleotide was eluted using a mobile phase of 20 mM sodium hydroxide and 2.5 M sodium chloride in 20% acetonitrile. The desired fraction was desalted using a G-25 Sephadex column against water for injection. Desalted samples were dried, reconstitutedand analyzed.

[0514] A useful protocol for GalNAc conjugation is described below as an example.

[0515]

[0516] = oligonucleotide chain

[0517] For example, pre-conjugation oligo sequence can be represented by the following structure.

[0518]

[0519] The tri-antennary GalNAc acid (hydroxyl groups protected as -OAc) can be represented by the following structure

[0520]

[0521] The tri-antennary GalNAc acid (hydroxyl groups protected as -OAc) and HATU were weighed out in a 50 mL plastic tube and dissolved in anhydrous acetonitrile then DIEAwas added into the tube. The resulting mixture was stirred for 10 min at 37 °C. Lyophilized pre -conjugation oligo sequence was reconstituted in water in a separate tube and the GalNAc mixture was added to the oligonucleotide solution and stirred for 60 min at 37 °C. The reaction was monitored by RP-UPLC. Reaction was complete in 1 hr. The reaction mixture was concentrated under vacuum to remove the acetonitrile and the resultant GalNAc-conjugated oligonucleotides is treated with cone, ammonia for 2 hr at 37°C. The formation of final product was confirmed by mass spectrometry and RP-UPLC. The conjugated material was purified by anion exchange chromatography and desalted using tangential flow filtration (TFF) to obtain the final product.

[0522] Additional chemical moieties can also be installed by coupling with phosphoramidites comprising such additional chemical moieties (and optional linkers), e.g., phosphoramidites comprising GalNAc such as those described in Example 1C. Additional technologies for preparing oligonucleotides are illustrated below as examples.

[0523] Example 1C. Example procedure for preparation of oligonucleotide compositions (50 jimol scale)

[0524] Certain stereopure oligonucleotides were synthesized at 50 pmol scale using a MerMadel2 synthesizer and standard CPG. In some embodiments, an amidite approach was used to incorporate GalNAc on the 5’ end. Generally, cyanoethyl amidites were used to prepare the PO linkages, DPSE amidites for the PS linkages and PSM amidites for the PN linkages. A typical MerMadel2, 50 pmol cycle is outlined in the table below:

[0525]

[0526] The cycles were performed multiple times until the desired length was achieved.

[0527] In some embodiments, an amidite approach was used to incorporate GalNAc on the5’ end. The GalNAc amidite, or, or tri-antennary GalNAc-acetyl derivative C6 phosphoramidite, can be represented by the following structure. The synthesis is disclosed in W02023201095 (Paragraph [001468])

[0528]

[0529] The GalNAc amidite was coupled either as a single 10-15 min or a two x 10 min procedure. For each coupling, 1.5 mL of 0.2M GalNAc amidite and 3 mL of CMIMT in ACN were added.

[0530] The first step of deprotection was performed on the synthesizer. 6 mL of 20% di ethylamine in ACN was added to the column for 10 min followed by washing with ACN and drying. CPG was transferred to a tube and 5 mL of fluoride solution was added. The fluoride solution consisted of dimethylsulfoxide, water, triethylamine trihydrofluoride, and triethylamine (15.5 / 3.1 / 1.0 / 1.8 volume ratio). After about 1 hour at room temperature, approximately 10 mL of 30% ammonium hydroxide was added, and the reaction incubated at 37°C overnight. The CPG was filtered off and washed with water and the filtrate collected.

[0531] The oligonucleotides were purified by anion exchange purification at room temperature. The oligonucleotide was loaded onto a column packed with Source Q15 resin after equilibration with a 20 mM sodium hydroxide in water or 20 mM sodium hydroxide with 20% acetonitrile in water mobile phase. The purified oligonucleotide was eluted as fractions by gradient elution with a mobile phase of 20 mM sodium hydroxide and 2.5 M sodium chloride in water or 20 mM sodium hydroxide and 2.5 M sodium chloride with 20% acetonitrile in water. Fractions were analyzed, pooled to the desired purity and desalted using a G-25 Sephadex column against water for injection. Desalted samples were dried, reconstituted and sterile filtered prior to final analysis including UPLC, LC-MS and UV-Vis.EXAMPLE 2. Synthesis of WV-NU-040

[0532]

[0533] WV-NU-040

[0534] 5 ’ -PO(OEt)2-triazolyl phosphonate-dT;

[0535] Diethyl (l-(((2R,3S,5R)-3-hydroxy-5-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-l(2H)- yl)tetrahydrofuran-2-yl)methyl)-lH-l,2,3-triazol-4-yl)phosphonate

[0536] General Scheme:

[0537]

[0538] WV-NU-040

[0539] Experimental Procedures:

[0540] 1. Preparation of compound 2A

[0541]

[0542] To a solution of compound 1A (10 g, 57.96 mmol) in THF (20 mL) was added to bromo(ethynyl)magnesium (0.5 M, 117.07 mL) at 0°C under N2. The resulting mixture was stirred at 20 °C for 0.5 hr. TLC showed compound 1 A was consumed completely and two new spots formed. The mixture was quenched by addition sat. NH4CI (aq., 50 mL) at 0°C, then diluted with Ethyl acetate (30 mL) and extracted with Ethyl acetate (150 mL*3). The combined organic layers were dried over Na2SO4, filtered and concentrated under reduced pressure to give crude. The residue was purified by column chromatography (SiO₂, petroleum ether / ethyl acetate = 10:1 to 1:1). Compound 2A (5.2 g, 55.34% yield) was obtained as a colorless oil.

[0543] LCMS: (M+H+): 163.3

[0544] TLC (Petroleum ether / Ethyl acetate = 1: 1) Rf = 0.43

[0545] 2. Preparation of compound 4

[0546]

[0547] To a solution of compound 3 (10 g, 28.05 mmol) in pyridine (200 mL) was added PPI13 (13.24 g, 50.49 mmol) and I2 (10.68 g, 42.08 mmol). The mixture was stirred at 25°C for 12 hr under N2 atmosphere. LCMS showed most of the starting material was disappeared and one main peak with desired mass was detected. The reaction mixture was quenched by sat. aq. Na₂SO₃ (200 mL) and extracted with EtOAc (600 mL*3). The combined organic layers were washed with brine (200 mL*2), dried over Na₂SO₄, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO₂, petroleum ether / ethyl acetate = 10:1 to 0:1). Compound 4 (4.8 g, 33.40% yield, 91.041% purity) was obtained as a colorless oil.

[0548] LCMS: (M+H+): 467.0

[0549] TLC (Petroleum ether / Ethyl acetate = 1: 3) Rf = 0.753. Preparation of compound 5

[0550]

[0551] To a solution of compound 4 (4.8 g, 10.29 mmol) in DMF (48 mL) was added NaNs (802.89 mg, 12.35 mmol). The mixture was stirred at 50°C for 12 hr. LCMS showed compound 4 was consumed completely and one main peak with desired MS was detected. The reaction was quenched by H2O (6 mL), and extracted with TBME (6 mL*3). Compound 5 (3.93 g, crude) in a yellow solution of TBME (18 mL) was used into the next step without further purification.

[0552] LCMS: (M+H+): 382.3

[0553] 4. Preparation of compound 6

[0554]

[0555] To a solution of compound 5 (3.93 g, 10.30 mmol) in THF (20 mL) was added N, N-diethylethanamine; trihydrofluoride (6.64 g, 41.21 mmol). The mixture was stirred at 20°C for 12 hr. TLC showed a few of compound 5 was remained and new spot was detected. The reaction mixture was concentrated under reduced pressure and the mixture was neutralized with Na₂CO₃ (aq., sat.) until pH = 7. The mixture was concentrated under reduced pressure to removed most of water. The mixture was added DCM (40 mL) and dried over Na₂SO₄, filtered and concentrated under reduced pressure to give a residue. The residue was purified by prep-TLC (SiO₂, Petroleum ether: (ethyl acetate: ethyl alcohol = 3:1) = 1:1). Compound 6 (2.7 g, crude) was obtained as a yellow oil.

[0556] TLC (petroleum ether: (ethyl acetate: ethyl alcohol = 3:1) = 1:1) Rf = 0.24

[0557] 5. Preparation of WV-NU-040

[0558]

[0559] 5’-PO(OEt)2-Triazolyl phosphonate-dT (VW-NU-040).

[0560] To a solution of compound 6 (2 g, 7.48 mmol) and 1- [ethoxy(ethynyl)phosphoryl]oxy ethane (1.42 g, 8.76 mmol) in DMF (20 mL) was degassed and purged with N2 for 3 times, then DIEA (1.93 g, 14.97 mmol), Cui (285.06 mg, 1.50 mmol) was added. The mixture was stirred at 20°C for 4 hr under N2 atmosphere. LCMS showed most of the starting material was disappeared and the desired substance was found. The reaction mixture was diluted with TMT solution (8 mL), filtered and the filtrate was diluted with ACN (80 mL), and concentrated under reduced pressure to give a residue. The residue was washed with EtOAc (100 mL*3), filtered and concentrated under reduced pressure to give product. WV-NU-040 (1.8 g, 3.92 mmol, 52.38% yield, 93.513% purity) was obtained as a white solid.

[0561] 'HNMR (400 MHz, DEUTERIUM OXIDE) 5 ppm 8.39 (s, 1 H), 6.96 (s, 1 H), 6.07 (t,.7=6,4 Hz, 1 H), 4.77 (d,.7=4,4 Hz, 2 H), 4.37 (q, J=6.2 Hz, 1 H), 4.19 (q,.7=4,9 Hz, 1 H), 4.01 - 4.14 (m, 4 H), 2.20 - 2.37 (m, 2 H), 1.73 (s, 3 H), 1.19 (s, 6 H)

[0562] 31P NMR (162 MHz, DEUTERIUM OXIDE) 5 ppm 8.67 (s, 1 P)

[0563] 13C NMR (101MHz, DEUTERIUM OXIDE) 5 = 166.21, 151.53, 137.29, 136.50, 134.08, 133.47, 133.14, 111.55, 85.38, 82.53, 70.15, 64.72, 64.66, 50.60, 36.90, 15.47, 15.41, 11.49.

[0564] LCMS: (M+H+): 430.1, LCMS purity: 93.513%.

[0565] EXAMPLE 3. Synthesis of WV-NU-306

[0566]

[0567] WV-NU-306

[0568] 2’-OMe-5’-PO(OEt)2 triazolyl phosphonate uridine;

[0569] Diethyl(l -(((2R,3R,4R, 5R)-5-(2,4-di oxo-3, 4-dihydropyrimidin-l(2H)-yl)-3-hydroxy-4-methoxytetrahydrofuran-2-yl)methyl)- 1H- 1,2,3 -triazol-4-yl)phosphonate

[0570] General Scheme:

[0571]

[0572] 1A 2A

[0573] To a solution compound 1A (10 g, 63.88 mmol) in THF (100 mL) was added bromo (ethynyl) magnesium (0.5 M, 124.75 mL) at 0°C under N2. The resulting mixture was stirred at 25 °C for 2 hr. TLC indicated compound 1A was consumed completely and two new spots formed. The reaction was clean according to TLC. The reaction mixture was quenched by sat. aq. NH4CI (100 mL) at 0°C, then extracted with DCM (50 mL*3). The combined organic layers were dried over Na₂SO₄, filtered to get the crude. Compound 2A (37.34 g, crude, together with four batches) was obtained as a brown liquid and used into the next step without further purification.TLC: Petroleum ether: Ethyl acetate = 2:1, Rf = 0.25

[0574] 2. Preparation of compound 3A:

[0575]

[0576] To a solution of compound 2A (37 g, 253.21 mmol) in DCM (1000 mL) was added m-CPBA (102.82 g, 506.42 mmol, 85% purity) at 0°C. The mixture was stirred at 0-25°C for 2 hr. TLC indicated compound 2A was consumed completely and one new spot formed. The reaction was clean according to TLC. The reaction mixture was quenched by sat. aq. Na2SO3(300 mL) and NaHCO3(300mL), then extracted with DCM (200 mL*3). The combined organic layers were washed with brine (100 mL*2), dried over Na2SO4, filtered, and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 1:0 to 0:1). Compound 3 A (55 g, 44.66% yield, together with three batches) was obtained as a colorless oil.

[0577] 'H NMR (400 MHz, CHLOROFORM-d) 5 = 4.16 - 4.07 (m, 4H), 2.97 (d, J = 13.3 Hz, 1H), 1.31 (dt, J = 0.7, 7.1 Hz, 6H)

[0578] 31P NMR (162 MHz, CHLOROFORM-d) 5 = -8.43 (s, IP)

[0579] TLC: Petroleum ether: Ethyl acetate = 1:1, Rf = 0.4

[0580] 3. Preparation of compound 2:

[0581]

[0582] To a solution of compound 1 (50 g, 193.63 mmol) in THF (700 mL) was added imidazole (34.27 g, 503.43 mmol), I2(78.63 g, 309.80 mmol) and PPh3(81.26 g, 309.80 mmol) at 0 °C. The mixture was stirred at 25°C for 12 hr. LCMS showed compound 1 was consumed completely and the desired mass was detected. The reaction was quenched by 10% aqueous sodium thiosulfate solution (500 ml). After removing the solvent and volatiles under reduced pressure, the residue was extracted into EtOAc (200 mL*3) and washed with saturated aqueous NaHCCh solution. The organic layer was separated, dried over anhydrous Na2SO4, filtered and concentrated. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 1:0 to 0:1). Compound 2 (270 g, 94.73% yield, together with four batches) was obtained as a white solid.H NMR (400 MHz, DMSO-d6) 5 = 11.42 (s, 1H), 7.68 (d, J = 8.0 Hz, 1H), 5.86 (d, J = 5.4 Hz, 1H), 5.69 (d, J = 8.0 Hz, 1H), 5.45 (d, J = 6.0 Hz, 1H), 4.06 - 4.01 (m, 1H), 4.00 - 3.96 (m, 1H), 3.85 (td, J = 5.0, 6.2 Hz, 1H), 3.55 (dd, J = 5.4, 10.6 Hz, 1H), 3.40 (dd, J = 6.9, 10.6 Hz, 1H), 3.34 (s, 3H)

[0583] LCMS (M+H+): 368.9

[0584] TLC: Petroleum ether: Ethyl acetate = 0:1, Rf = 0.5

[0585] 4. Preparation of compound 3:

[0586]

[0587] To a solution of compound 2 (10 g, 27.16 mmol) in DMF (100 mL) was added NaNs (1.86 g, 28.66 mmol) at 0°C. The mixture was stirred at 0-50°C for 3 hr. LCMS showed compound 2 was consumed completely and the desired mass was detected. The reaction was quenched by H2O (1500 mL), and extracted with ethyl acetate (500 mL*3). The combined organic layers were washed with saturated aqueous NaCl 100 mL, dried over Na₂SO₄, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO₂, petroleum ether: ethyl acetate = 1:0 to 0: 1). The crude product was purified by re-crystallization from DCM (200 mL) at 25 °C. Compound 3 (57 g, 93.44% yield, together with six batches ) was obtained as a white solid.

[0588] H NMR (400 MHz, DMSO-d6) 5 = 11.41 (br s, 1H), 7.70 (d, J = 8.0 Hz, 1H), 5.83

[0589] = 5.3 Hz,

[0590]

[0591] To a solution of compound 3 (9.31 g, 57.42 mmol) and compound 3 A (9.31 g, 57.42 mmol) in THF (140 mL) was degassed and purged with N2 for 3 times, then DIE A (12.69 g, 98.15 mmol), Cui (18.69 g, 98.15 mmol) was added. The mixture was stirred at 25°C for 4 hr under N2 atmosphere. LCMS showed compound 3 was consumed completely and the desired mass was detected. The reaction mixture was concentrated under reduced pressure to give product. The residue was purified by column chromatography (SiO₂, Petroleum ether: Acetonitrile = 1: 0 to 0: 1 to Dichloromethane: Methanol =1: 0 to 0: 1). Compound WV-NU-306 (56 g, 62.92% yield, together with two batches) was obtained as a yellow solid. Batch 2 (46.43 g):

[0592] 'H NMR (400 MHz, CHLOROFORM-d) 5 = 9.79 (br s, 1H), 8.27 (s, 1H), 7.03 (d, J = 8.0 Hz, 1H), 5.72 (d, J = 8.0 Hz, 1H), 5.62 (d, J = 2.4 Hz, 1H), 4.96 - 4.70 (m, 2H), 4.30 - 4.12 (m, 6H), 3.97 (dd, J = 2.4, 4.9 Hz, 1H), 3.55 (s, 3H), 3.48 (s, 1H), 1.35 (t, J = 7.0 Hz, 6H)

[0593] 31P NMR (162 MHz, CHLOROFORM-d) 5 = 6.69 (s, IP)

[0594] LCMS (M+H+):446.1, purity: 97.42%

[0595] TLC: DCM: MeOH =10:1, Rf = 0.65

[0596] Batch 3 (9.22 g):

[0597] ‘HNMR (400 MHz, CHLOROFORM-d) 5 = 9.54 (s, 1H), 8.27 (s, 1H), 7.01 (d, J = 8.0 Hz, 1H), 5.73 (dd, J = 1.6, 8.0 Hz, 1H), 5.62 (d, J = 2.3 Hz, 1H), 4.95 - 4.88 (m, 1H), 4.75 (dd, J = 5.6, 14.4 Hz, 1H), 4.30 - 4.15 (m, 6H), 3.97 (dd, J = 2.2, 4.8 Hz, 1H), 3.56 (s, 3H), 3.52 (br d, J = 6.6 Hz, 1H), 1.36 (t, J = 7.0 Hz, 6H)

[0598] 31P NMR (162 MHz, CHLOROFORM-d) 5 = 6.64 (s, IP)

[0599] LCMS (M+H+): 446.1, purity: 93.76%

[0600] TLC: DCM: MeOH =10:1, Rf = 0.65

[0601] EXAMPLE 4. Synthesis of WV-NU-332

[0602]

[0603] WV-NU-332

[0604] 2’-OMe-5’-bis(pivaloyloxymethyl)-triazolyl phosphonate uridine;

[0605] [(((l-(((2R,3R,4R,5R)-5-(2,4-dioxo-3,4-dihydropyrimidin-l(2H)-yl)-3-hydroxy-4- methoxytetrahydrofuran-2-yl)m ethyl)- 1 H- 1,2,3 -triazol -4- yl)phosphoryl)bis(oxy))bis(methylene) bis(2,2-dimethylpropanoate)]

[0606] General Scheme:

[0607]

[0608] WV-NU-332

[0609] Experimental Procedure:

[0610] / . Preparation of compound 2C:

[0611]

[0612] To a solution of compound 1C (10 g, 69.21 mmol, 7.46 mL) in THF (100 mL) wasadded bromo(ethynyl)magnesium (0.5 M, 166.10 mL) under N2. The mixture was stirred at 0-25°C for 2 hr. TLC indicated compound 1C was consumed completely and one new spot formed. The reaction mixture was quenched by addition NH4CI 50 mL at 0°C, and then diluted with water 50 mL and extracted with EtOAc (100 mL*3). The combined organic layers were dried over Na2SO4, filtered, and concentrated under reduced pressure to give a residue. Without purification. Compound 2C (9 g, crude) was obtained as a yellow oil.

[0613] TLC: Petroleum ether: Ethyl acetate = 0:l, Rf= 0.34

[0614] 2. Preparation of compound 5 A:

[0615]

[0616] To a solution of compound 2C (9 g, 67.13 mmol) in ACN (200 mL) was added 4A MS (2 g, 67.13 mmol), iodomethyl 2,2-dimethylpropanoate (48.75 g, 201.39 mmol). The mixture was stirred at 82°C for 10 hr. TLC indicated compound 2C was consumed completely and two new spots formed. The reaction mixture was filtered and concentrated under reduced pressure to give a residue. Compound 5A (5 g, 22.28% yield) was obtained as a colorless oil

[0617] 'H NMR (400 MHz, CHLOROFORM-d) 5 = 5.72 (d, J = 1.6 Hz, 2H), 5.69 (d, J = 0.9 Hz, 2H), 3.03 (d, J = 14.3 Hz, 1H), 1.22 (s, 18H)

[0618] 31P NMR (162 MHz, CHLOROFORM-d) 5 = 10.31 (s, IP)

[0619] TLC: Petroleum ether: Ethyl acetate = 3:1, Rf = 0.38

[0620] 3. Preparation of compound 2:

[0621]

[0622] To a solution of compound 1 (50 g, 193.63 mmol) in THF (700 mL) was addedimidazole (34.27 g, 503.43 mmol), I2(78.63 g, 309.80 mmol) and PPh3(81.26 g, 309.80 mmol) at 0°C. The mixture was stirred at 25°C for 12 hr. LCMS showed compound 1 was consumed completely and the desired mass was detected. The reaction was quenched by 10% aqueous sodium thiosulfate solution (500 ml). After removing the solvent and volatiles under reduced pressure, the residue was extracted into EtOAc (200 mL*3) and washed with saturated aqueous NaHCCh solution. The organic layer was separated, dried over anhydrous Na2SO4, filtered and concentrated. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 1:0 to 0:1). Compound 2 (270 g, 94.73% yield, together with four batches) was obtained as a white solid.

[0623] 1H NMR (400 MHz, DMSO-d6) 5 = 11.42 (s, 1H), 7.68 (d, J = 8.0 Hz, 1H), 5.86 (d, J = 5.4 Hz, 1H), 5.69 (d, J = 8.0 Hz, 1H), 5.45 (d, J = 6.0 Hz, 1H), 4.06 - 4.01 (m, 1H), 4.00 - 3.96 (m, 1H), 3.85 (td, J = 5.0, 6.2 Hz, 1H), 3.55 (dd, J = 5.4, 10.6 Hz, 1H), 3.40 (dd, J = 6.9, 10.6 Hz, 1H), 3.34 (s, 3H)

[0624] LCMS (M+H+): 368.9

[0625] TLC: Petroleum ether: Ethyl acetate = 0:1, Rf = 0.5

[0626] 4. Preparation of compound 3:

[0627]

[0628] To a solution of compound 2 (10 g, 27.16 mmol) in DMF (100 mL) was added NaN3(1.86 g, 28.66 mmol) at 0°C. The mixture was stirred at 0-50°C for 3 hr. LCMS showed compound 2 was consumed completely and the desired mass was detected. The reaction was quenched by H2O (1500 mL), and extracted with Ethyl acetate (500 mL*3). The combined organic layers were washed with saturated aqueous NaCl 100 mL, dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 1:0 to 0:1). The crude product was purified by re-crystallization from DCM (200 mL) at 25°C. Compound 3 (57 g, 93.44% yield, together with six batches) was obtained as a white solid.

[0629] 'HNMR (400 MHz, DMSO-d6) 5 = 11.41 (br s, 1H), 7.70 (d, J = 8.0 Hz, 1H), 5.83(d, J = 4.9 Hz, 1H), 5.68 (d, J = 8.0 Hz, 1H), 5.35 (br d, J = 6.0 Hz, 1H), 4.07 (q, J = 5.3 Hz, 1H), 3.95 - 3.89 (m, 2H), 3.61 (d, J = 4.9 Hz, 2H), 3.36 (s, 3H)

[0630] LCMS: (M+H+): 284.0, LCMS purity: 100%

[0631] TLC: Petroleum ether: Ethyl acetate = 0:l, Rf= 0.45

[0632]

[0633] To a solution of compound 3 (3 g, 10.59 mmol) and compound 5A (4.25 g, 12.71 mmol, 1.2 eq) in H2O (10 mL) was degassed and purged with nitrogen for 3 times, sodium ascorbate (2.52 g, 12.71 mmol, 1.2 eq), diacetoxycopper (2.31 g, 12.71 mmol) was added. The mixture was stirred at 65°C for 6 hr under N2 atmosphere. TLC indicated compound 5A was consumed completely and one new spot formed. The reaction mixture was filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCh, Petroleum ether: Ethyl acetate = 15:1 to 0:1 to Ethyl acetate: MeCN = 10:1 to 0:1 to Ethyl acetate: Methanol = 8:1 ). Compound WV-NU-332 (2 g, 46.67% yield, 70% purity) was obtained as a white solid.

[0634] 1HNMR(400 MHz, DMSO-d6) 5 = 11.47 - 11.35 (m, 2H), 8.69 (s, 1H), 7.62 (d, J = 8.1 Hz, 1H), 5.80 (d, J = 5.0 Hz, 1H), 5.70 (s, 2H), 5.67 (s, 2H), 5.51 (d, J = 5.8 Hz, 1H), 4.80 (d, J = 3.8 Hz, 1H), 4.18 - 4.15 (m, 1H), 3.96 - 3.89 (m, 2H), 3.61 (d, J = 4.8 Hz, 1H), 3.36 (s, 3H), 1.06 (s, 18H)

[0635] 31P NMR (162 MHz, DMSO-de) 5 = 7.08 (s, IP)

[0636] LCMS:(M+H+):618.2, purity: 70.8%

[0637] TLC: Petroleum ether: Ethyl acetate = 0:1, Rf = 0.06

[0638] EXAMPLE 5. Synthesis of WV-NU-336

[0639]

[0640] WV-NU-336

[0641] 2’-OMe-5’-bis(2-cyanoethyl)-triazolyl phosphonate uridine;

[0642] Bis(2-cyanoethyl)(l-(((2R,3R,4R,5R)-5-(2,4-di oxo-3, 4-dihydropyrimidin-l(2H)-yl)-3- hydroxy-4-methoxytetrahydrofuran-2-yl)methyl)- 1H- 1,2,3-triazol-4-yl)phosphonate

[0643] General Scheme:

[0644]

[0645] WV-NU-336

[0646] Experimental Procedure:

[0647] J. Preparation of compound 3B:

[0648]

[0649] 1B 3BTo a solution ofPCh (35 g, 254.86 mmol) in THF (1000 mL) was added TEA (51.58 g, 509.71 mmol, 70.95 mL) and 3 -hydroxypropanenitrile (36.23 g, 509.71 mmol, 34.67 mL). The mixture was stirred at 25°C for 2 hr. TLC indicated compound IB was consumed completely and one new spot formed. The reaction mixture was filtered and concentrated under reduced pressure to give a residue. Compound 3B (44 g, 83.58% yield) was obtained as a colorless oil.

[0650] TLC: Petroleum ether: Ethyl acetate = 0:1, Rf = 0.12

[0651]

[0652] 3B 4B

[0653] To a solution of compound 3B (10 g, 48.41 mmol) in THF (100 mL) was added bromo(ethynyl)magnesium (0.5 M, 116.19 mL) at 0 °C. The mixture was stirred at 0-25°C for 5 hr. TLC indicated compound 3B was consumed completely and two new spots formed. The reaction mixture was quenched by addition NH4CI 50 mL at 0°C, and then diluted with water 100 mL and extracted with EtOAc (100 mL*3). The combined organic layers were dried over Na2SO4, filtered, and concentrated under reduced pressure to give a residue. Compound 4B (6 g, 63.19% yield) was obtained as a yellow oil.

[0654] 1H NMR (400 MHz, CHLOROFORM-d) 5 = 4.17 - 4.09 (m, 4H), 3.19 (d, J = 2.1 Hz, 1H), 2.67 (t, J = 6.1 Hz, 4H)

[0655] 31P NMR (162 MHz, CHLOROFORM-d) 5 = 132.04 (s, IP)

[0656] For the scale up batch:

[0657] To a solution of compound 3B (44 g, 213.01 mmol) in THF (1000 mL) was added bromo(ethynyl)magnesium (0.5 M, 511.22 mL) at 0°C. The mixture was stirred at 0-25°C for 3hr. TLC indicated compound 3B was consumed completely and two new spots formed. The reaction mixture was quenched by sat. NH4CI (200 mL) at 0°C, then extracted with DCM (500 mL*3). The combined organic layers were dried over Na2SO4, filtered to get the crude. No purification. Compound 4B (40 g, crude) was obtained as a yellow oil.

[0658] TLC: petroleum ether: ethyl acetate = 1:1, Rf = 0.39

[0659]

[0660] 4B5B

[0661] To a solution of compound 4B (40 g, 203.93 mmol) in DCM (1000 mL) was added mCPBA (62.10 g, 305.90 mmol, 85% purity). The mixture was stirred at 0-25°C for 2 hr. TLC indicated compound 4B was consumed completely and one new spot formed. The reaction mixture was quenched by sat. Na2SO3 (2000 mL) and NaHCCL (2000mL), then extracted with DCM (1000 mL*2). The combined organic layers were washed with brine (500ml), dried over Na2SO4, filtered, and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 10:1 to 0:1). Compound 5 B (13 g, 30.05% yield) was obtained as a yellow oil.

[0662] 'H NMR (400 MHz, CHLOROFORM-d) 5 = 4.37 - 4.29 (m, 4H), 3.16 (dd, J = 1.3, 13.9 Hz, 1H), 2.81 (t, J = 6.1 Hz, 4H)

[0663] 31P NMR (162 MHz, CHLOROFORM-d) 5 = -8.61 (s, IP)

[0664] TLC: Petroleum ether: Ethyl acetate = 1:1, Rf = 0.23

[0665] 4. Preparation of compound 2:

[0666]

[0667] To a solution of compound 1 (50 g, 193.63 mmol) in THF (700 mL) was added imidazole (34.27 g, 503.43 mmol), I2(78.63 g, 309.80 mmol) and PPh3(81.26 g, 309.80 mmol) at 0°C. The mixture was stirred at 25°C for 12 hr. LCMS showed compound 1 was consumed completely and the desired mass was detected. The reaction was quenched by 10% aqueous sodium thiosulfate solution (500 ml). After removing the solvent and volatiles under reduced pressure, the residue was extracted into EtOAc (200 mL*3) and washed with saturated aqueous NaHCO3 solution. The organic layer was separated, dried over anhydrous Na2SO4, filtered and concentrated. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 1:0 to 0:1). Compound 2 (270 g, 94.73% yield, together with four batches) was obtained as a white solid.1H NMR (400 MHz, DMSO-d6) 5 = 11.42 (s, 1H), 7.68 (d, J = 8.0 Hz, 1H), 5.86 (d, J = 5.4 Hz, 1H), 5.69 (d, J = 8.0 Hz, 1H), 5.45 (d, J = 6.0 Hz, 1H), 4.06 - 4.01 (m, 1H), 4.00 - 3.96 (m, 1H), 3.85 (td, J = 5.0, 6.2 Hz, 1H), 3.55 (dd, J = 5.4, 10.6 Hz, 1H), 3.40 (dd, J = 6.9, 10.6 Hz, 1H), 3.34 (s, 3H)

[0668] LCMS (M+H+): 368.9

[0669] TLC: Petroleum ether: Ethyl acetate = 0:1, Rf = 0.5

[0670] 5. Preparation of compound 3:

[0671]

[0672] To a solution of compound 2 (10 g, 27.16 mmol) in DMF (100 mL) was added NaNs (1.86 g, 28.66 mmol) at 0°C. The mixture was stirred at 0-50°C for 3 hr. LCMS showed compound 2 was consumed completely and the desired mass was detected. The reaction was quenched by H2O (1500 mL), and extracted with Ethyl acetate (500 mL*3). The combined organic layers were washed with saturated aqueous NaCl 100 mL, dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, petroleum ether: ethyl acetate = 1:0 to 0:1). The crude product was purified by re-crystallization from DCM (200 mL) at 25°C. Compound 3 (57 g, 93.44% yield) was obtained as a white solid.

[0673] 'HNMR (400 MHz, DMSO-d6) 5 = 11.41 (br s, 1H), 7.70 (d, J = 8.0 Hz, 1H), 5.83 (d, J = 4.9 Hz, 1H), 5.68 (d, J = 8.0 Hz, 1H), 5.35 (br d, J = 6.0 Hz, 1H), 4.07 (q, J = 5.3 Hz, 1H), 3.95 - 3.89 (m, 2H), 3.61 (d, J = 4.9 Hz, 2H), 3.36 (s, 3H)

[0674] LCMS: (M+H+): 284.0, LCMS purity: 100%

[0675] TLC: Petroleum ether: Ethyl acetate = 0:1, Rf = 0.45

[0676] 6. Preparation of compound WV-NU-336:

[0677]

[0678] To a solution of compound 3 (5 g, 17.65 mmol) and compound 5B (4.49 g, 21.18 mmol) in THF (10 mL) and H2O (10 mL) was degassed and purged with N2 for 3 times, then CUSO4.5H2O (5.29 g, 21.18 mmol), sodium ascorbate (4.20 g, 21.18 mmol) was added. The mixture was stirred at 65°C for 10 hr under N2 atmosphere. LCMS showed compound 3 was consumed completely and desired mass was detected. The reaction mixture was filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCh, petroleum ether: ethyl acetate = 10:1 to 0:1, ethyl acetate MeCN = 8: 1 to 0: 1). Compound WV-NU-336 (5.3 g, 60.61% yield) was obtained as a white solid.

[0679] 1H NMR (400 MHz, DMSO-d6) 5 = 11.40 (d, J = 1.6 Hz, 1H), 8.72 (s, 1H), 7.60 (d, J = 8.0 Hz, 1H), 5.79 (d, J = 4.8 Hz, 1H), 5.66 (dd, J = 2.1, 8.0 Hz, 1H), 5.50 (d, J = 6.1 Hz, 1H), 4.87 - 4.73 (m, 2H), 4.32 - 4.17 (m, 5H), 4.14 (q, J = 5.5 Hz, 1H), 3.93 (t, J = 5.0 Hz, 1H), 3.36 (s, 3H), 2.95 (t, J = 5.9 Hz, 4H)

[0680] 31P NMR (162 MHz, DMSO-d6) 5 = 7.72 (s, IP)

[0681] LCMS (M+H+): 496.1, purity: 93.49%

[0682] TLC: di chloromethane: methanol = 8:1, Rf = 0.13

[0683] EXAMPLE 6. Synthesis of WV-NU-347

[0684]

[0685] WV-NU-347

[0686] 2'-Fluoro-5'-PO(POM)2-Triazolyl Phosphonate Uridine (WV-NU-347)

[0687] (((1-(((2R,3R,4R,5R)-5-(2,4-dioxo-3,4-dihydropyrimidin-1(2 / - / )-yl)-4-fluoro-3- hydroxytetrahydrofuran-2-yl)methyl)-1 / 7-1,2,3-triazol-4- yl)phosphoryl)bis(oxy))bis(methylene) bis(2,2-dimethylpropanoate)

[0688] General Scheme:

[0689]

[0690] WV-NU-347

[0691] 2'-Fluoro-5'-PO(POM)2-Triazolyl Phosphonate Uridine (WV-NU-347)

[0692] Experimental Procedure:

[0693] 1. Preparation of compound 2C:

[0694]

[0695] 1C 2CTo a solution of compound 1C (36 g, 249.15 mmol) in THF (400 mL) was added bromo(ethynyl)magnesium (0.5 M, 498.29 mL) under N2. The mixture was stirred at 0-25°C for 2 hr. TLC indicated compound 1C was consumed completely and one new spot formed. Each reaction mixture was quenched by addition NH4CI lOOmL at 0°C, and then diluted with water 300 mL and extracted with EtOAc (100 mL*3). The combined organic layers were dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, petroleum ether: ethyl acetate = 10: 1 to 0: 1). Compound 2C (28.5 g, 28.44% yield) was obtained as a yellow oil.

[0696] TLC: Petroleum ether: Ethyl acetate = 0:1, Rf = 0.35

[0697] 2. Preparation of compound 5A:

[0698]

[0699] To a solution of compound 2C (9.5 g, 70.86 mmol) in ACN (500 mL) was added 4A MS (3 g, 70.86 mmol), iodomethyl 2,2-dimethylpropanoate (68.61 g, 283.43 mmol). The mixture was stirred at 82°C for 15 hr. TLC indicated Reactant 1 was consumed completely and two new spots formed. The reaction mixture was filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, petroleum ether: ethyl acetate = 10: 1 tol: 1). Compound 5A (45 g, 63.32% yield) was obtained as a colorless oil.

[0700] 'HNMR (400 MHz, CHLOROFORM-d) 5 = 5.72 (d, J = 1.2 Hz, 2H), 5.68 (s, 2H), 3.04 (d, J = 14.3 Hz, 1H), 1.22 (s, 18H)

[0701] 31P NMR (162 MHz, CHLOROFORM-d) 5 = -10.36 (s, 1P)

[0702] TLC: Petroleum ether: Ethyl acetate = 3:1, Rf = 0.38

[0703] 3. Preparation of compound 2:

[0704]

[0705] To a solution of compound 1 (15 g, 60.93 mmol) in THF (210 mL) was added imidazole (10.78 g, 158.41 mmol), I2 (24.74 g, 97.48 mmol) and PPh3 (25.57 g, 97.48 mmol) at 0°C. The mixture was stirred at 25°C for 4 hr. LCMS showed compound 1 was consumed completely and the desired mass was detected. The reaction was quenched by 10% aqueous sodium thiosulfate solution (100 ml). After removing the solvent and volatiles under reduced pressure, the residue was extracted into EtOAc (50 mL*5) and washed with saturated aqueous NaHCO3 solution. The organic layer was separated, dried over anhydrous Na2SO4, filtered and concentrated. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 1:0 to 0:1 to Dichloromethane: Methanol =1:0 to 3: 1). The crude product was purified by re-crystallization from Ethyl acetate (100 mL) and Methanol (10 mL) at 15°C. Compound 2 (43 g (total three batches), 66.15% yield,) was obtained as a yellow solid.

[0706] 'HNMR (400 MHz, DMSO-d6) 5 = 11.46 (br s, 1H), 7.66 (d, J = 8.0 Hz, 1H), 5.94 - 5.79 (m, 2H), 5.66 (d, J = 8.0 Hz, 1H), 5.33 - 5.13 (m, 1H), 4.10 - 3.98 (m, 1H), 3.77 (dt, J = 3.4, 7.2 Hz, 1H), 3.60 (dd, J = 3.6, 11.0 Hz, 1H), 3.41 (dd, J = 6.8, 11.0 Hz, 1H)

[0707] 19F NMR (376 MHz, DMSO-d6) δ = -199.11 (s, 1F)

[0708] LCMS (M+H+): 356.9, purity: 95.16%

[0709] TLC: Dichloromethane: Methanol = 10:1, Rf = 0.45

[0710] 4. Preparation of compound 3:

[0711]

[0712] 2 3

[0713] To a solution of compound 2 (10 g, 28.08 mmol) in 1,2-dimethoxy ethane (100 mL) and H2O (20 mL) was added NaNs (1.83 g, 28.08 mmol) at 0°C under N2. The mixture wasstirred at 90°C for 12 hr. LCMS showed compound 2 was remained and the desired mass was detected. The reaction was quenched by H2O (50 mL), and extracted with ethyl acetate (100 mL*3). The combined organic layers were washed with saturated aqueous NaCl 50 mL, dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 1:0 to 0:1). The crude product was purified by re-crystallization from ethyl acetate (100 mL) at 20°C. Compound 3 (28 g, 85.63% yield) was obtained as a white solid.

[0714] 'HNMR (400 MHz, DMSO-d6) 5 = 11.45 (br s, 1H), 7.67 (d, J = 8.0 Hz, 1H), 5.90 - 5.81 (m, 1H), 5.75 (br s, 1H), 5.66 (d, J = 8.0 Hz, 1H), 5.29 - 5.10 (m, 1H), 4.31 - 4.17 (m, 1H), 3.94-3.93 (m, 1H), 3.79 - 3.48 (m, 2H)

[0715] 19F NMR (376 MHz, DMSO-d6) δ = -198.74 (s, 1F)

[0716] LCMS: (M+H+): 272.0, purity: 92.29%

[0717] TLC: Dichloromethane: Methanol = 10:1, Rf = 0.45

[0718] 5. Preparation of WV-NU-347:

[0719]

[0720] - - 2'-Fluoro-5'-(POM)2-T riazolyl Phosphonate Uridine (WV-NU-347)

[0721] To a solution of compound 3 (5 g, 18.44 mmol) and compound 5 A (7.40 g, 22.12 mmol) in H2O (25 mL) and THF (25 mL) was degassed and purged with N2 for 3 times, CUSO4.5H2O (5.52 g, 22.12 mmol), sodium ascorbate (4.38 g, 22.12 mmol) was added. The mixture was stirred at 65°C for 3 hr under N2 atmosphere. LCMS showed compound 3 was consumed completely and the desired mass was detected. The reaction mixture was extracted with ethyl acetate (30mL*3). The combined organic layers were washed with saturated aqueous NaCl 20 mL, dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate=1:0 to 0:1 to ethyl acetate: methanol=1:0 to 2:1). Compound WV-NU-347 (14.5 g, 65.91% yield) was obtained as a yellow solid.1HNMR(400MHz, DMSO-d6) 5= 11.42 (d, J = 1.6 Hz, 1H), 8.71 (s, 1H), 7.56 (d, J = 8.2 Hz, 1H), 5.91 (d, J = 6.0 Hz, 1H), 5.87 - 5.78 (m, 1H), 5.69 (d, J = 13.8 Hz, 4H), 5.62 (dd, J = 2.0, 8.1 Hz, 1H), 5.31 - 5.09 (m, 1H), 4.91 -4.71 (m, 2H), 4.30 - 4.16 (m, 2H), 1.08 (s, 18H)

[0722] 31P NMR (162 MHz, DMSO-d6) δ = 7.04 (s, 1P)

[0723] 19F NMR (376 MHz, DMSO-d6) δ = -199.16 (s, 1F)

[0724] LCMS (M+H+): 606.2, purity: 98.32%

[0725] TLC: Petroleum ether: Ethyl acetate = 0:1, Rf = 0.55

[0726] EXAMPLE 7. Synthesis of WV-NU-348

[0727]

[0728] WV-NU-348

[0729] 2'-OMOE-5'-PO(POM)2-Triazolyl Phosphonate Uridine (WV-NU-348)

[0730] (((l-(((2R,3R,4R,5R)-5-(2,4-dioxo-3,4-dihydropyrimidin-l(2H)-yl)-3-hydroxy-4-(2- methoxy ethoxy )tetrahydrofuran-2-yl)methyl)-lH-l, 2, 3-triazol-4- yl)phosphoryl)bis(oxy))bis(methylene) bis(2,2-dimethylpropanoate)

[0731] General Scheme:

[0732]

[0733]

[0734] WV-NU-348

[0735] Experimental Procedure:

[0736] 1. Preparation of compound 2C:

[0737]

[0738] 1C 2C

[0739] To a solution of compound 1C (36 g, 249.15 mmol, 26.87 mL) in THF (400 mL) was added bromo(ethynyl)magnesium (0.5 M, 498.29 mL) under N2. The mixture was stirred at 0-25°C for 2 h. TLC indicated compound 1C was consumed completely and one new spot formed. The each reaction mixture was quenched by addition NH4CI 100 mL at 0°C, and then diluted with water 300 mL and extracted with EtOAc (100 mL*3). The combined organic layers were dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCh, petroleum ether: ethyl acetate = 10:1 to 0:1). Compound 2C (23 g, 17.21% yield) was obtained as a yellow oil.

[0740] 1H NMR (400 MHz, CHLOROFORM-d) δ = 3.82 (s, 3H), 3.80 (s, 3H), 2.96 (d, J =

[0741]

[0742] To a solution of compound 2C (11.5 g, 85.78 mmol) in ACN (500 mL) was added 4A MS (5 g, 85.78 mmol), iodomethyl 2,2-dimethylpropanoate (83.05 g, 343.10 mmol)The mixture was stirred at 82°C for 15h. TLC indicated compound 2C was consumed completely and two new spots formed. The reaction mixture was filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 10:1 to 0:1). Compound 5A (33 g, 57.89% yield) was obtained as a colorless liquid.

[0743] 'H NMR (400 MHz, CHLOROFORM-d) 5 = 5.70 (d, J = 1.5 Hz, 2H), 5.66 (d, J = 0.8 Hz, 2H), 3.06 (d, J = 14.3 Hz, 1H), 1.20 (s, 18H)

[0744] 31P NMR (162 MHz, CHLOROFORM-d) δ = -10.31 (s, 1P)

[0745] TLC: Petroleum ether: Ethyl acetate = 3: 1, Rf = 0.38

[0746] 3. Preparation of compound 2:

[0747]

[0748] To a solution of compound 2 (17.5 g, 57.89 mmol) in THF (400 mL) was added imidazole (10.25 g, 150.52 mmol), I2 (23.51 g, 92.63 mmol, 18.66 mL) and PPh3 (24.30 g, 92.63 mmol) at 0°C. The mixture was stirred at 20°C for 12 h. LCMS showed compound 2 was consumed completely and one main peak with desired mass was detected. Two reactions were combined for work up. The reaction mixture was quenched by addition 10% Na2S2O3 aq. 100 mL at 25°C, and then concentrated under reduced pressure to remove THF, diluted with H2O (700 mL) and extracted with EtOAc (500 mL*2). The combined organic layers were washed with brine (600 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The crude product was used directly for the next step without purification. Compound 2 (48 g, crude) was obtained as a yellow oil.

[0749] LCMS: (M+H+): 412.9

[0750] 4. Preparation of compound 3:

[0751]

[0752] To a solution of compound 2 (22 g, 53.38 mmol) in DMF (250 mL) was added NaNs (3.09 g, 47.53 mmol) at 0°C under N2. The mixture was stirred at 90°C for 12 h. LCMS showed compound 2 was consumed completely and desired mass was detected. The reaction was quenched by H2O (500 mL), and extracted with Ethyl acetate (500 mL*3). The combined organic dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 1:0 to 0:1). Compound 3 (34 g, crude) was obtained as a yellow oil.

[0753] ‘HNMR (400 MHz, DMSO-d6) 5 = 11.40 (s, 1H), 7.70(d, J = 8.2 Hz, 1H), 5.82 (d, J = 4.5 Hz, 1H), 5.68 (d, J = 7.8 Hz, 1H), 5.26 (d, J = 5.6 Hz, 1H), 4.10 - 4.02 (m, 2H), 3.92 (q, J = 4.8 Hz, 1H), 3.74 - 3.67 (m, 1H), 3.66 - 3.57 (m, 3H), 3.47 - 3.42 (m, 2H), 3.25 - 3.20 (m, 3H)

[0754] LCMS: (M+H+): 328.2

[0755] TLC: Petroleum ether: Ethyl acetate = 0: 1, Rf = 0.34

[0756] 5. Preparation of compound WV-NU-348:

[0757]

[0758] 2'-OMOE-5'-PO(POM)2-Triazolyl Phosphonate Uridine (WV-NU-348) To a solution of compound 3 (11.5 g, 35.14 mmol) and compound 5 A (15.27 g, 45.68 mmol) in THF (50 mL) and H2O (50 mL) was added sodium ascorbate (8.35 g, 42.16 mmol) and CUSO4.5H2O (10.53 g, 42.16 mmol). The mixture was stirred at 65°C for 6 h. LCMS showed compound 3 was consumed completely and desired mass was detected. The mixture was concentrated, the reaction mixture was extracted with EtOAc (50 mL*3) andH2O 50 mL. Then the combined organic layers were dried over Na2SO4, filtered and concentrated. The residue was purified by column chromatography (SiCh, petroleum ether: ethyl acetate = 1:0 to 0: 1). Compound WV-NU-348 (10.7 g, 45.48% yield, 97.77% purity) was obtained as a yellow solid.

[0759]

[0760]

[0761]

[0762] Experimental Procedure:

[0763] 1. Preparation of compound 2C:

[0764]

[0765] 1C 2C

[0766] To a solution of compound 1C (36 g, 249.15 mmol) in THF (400 mL) was added bromo (ethynyl) magnesium (0.5 M, 498.29 mL) under N2. The mixture was stirred at 0-25°C for 2 hr. TLC indicated compound 1C was consumed completely and one new spot formed. The each reaction mixture was quenched by addition NH4CI lOOmL at 0°C. And then diluted with water 300 mL and extracted with EtOAc (100 mL*3). The combined organic layers were dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCh, petroleum ether: ethyl acetate = 10:1 to 0:1). Compound 2C (23 g, 17.21% yield) was obtained as a yellow oil.

[0767] 1H NMR (400 MHz, CHLOROFORM-d) δ = 3.82 (s, 3H), 3.79 (s, 3H), 2.97 (d, J = 13.4 Hz, 1H)

[0768] 31P NMR (162 MHz, CHLOROFORM-d) δ = -5.07 - -5.22 (m, 1P)

[0769] TLC: Petroleum ether: Ethyl acetate = 0:1, Rf = 0.31

[0770] 2. Preparation of compound 5A:

[0771]

[0772] To a solution of compound 2C (11.5 g, 85.78 mmol) in ACN (500 mL) was added 4A MS (5 g, 85.78 mmol), iodomethyl 2,2-dimethylpropanoate (83.05 g, 343.10 mmol). The mixture was stirred at 82°C for 15 hr. TLC indicated compound 2C was consumed completely and two new spots formed. The reaction mixture was filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCh, petroleum ether: ethyl acetate = 10:1 to 0:1). Compound 5A (33 g, 57.89% yield) was obtained as a colorless.

[0773] 'H NMR (400 MHz, CHLOROFORM-d) 5 = 5.70 (d, J = 1.5 Hz, 2H), 5.66 (d, J = 0.8Hz, 2H), 3.06 (d, J = 14.3 Hz, 1H), 1.20 (s, 18H)

[0774] 31P NMR (162 MHz, CHLOROFORM-d) δ = -10.31 (s, 1P)

[0775] TLC: petroleum ether: ethyl acetate = 3:1, Rf = 0.38

[0776] 3. Preparation of compound 2:

[0777]

[0778] 1 2

[0779] To a solution of compound 1 (50 g, 161.11 mmol) in DCM (800 mL) was added pyridine (82.84 g, 1.05 mol) and the mixture was cooled to 0°C, then MsCl (46.18 g, 403.14 mmol) was slowly added the mixture. The mixture was stirred at 0-20°C for 12 hr. LCMS showed compound 1 was consumed completely and desired mass was detected. The mixture was cooled to 0°C, the mixture of 100 mL ice water and aqueous NaHCCL 100 mL was dropped to the mixture under N2, and stirred for 5 min. The organic layer was separated and washed with saturated aqueous NaHCCL (300 ml *2) and with water. The combined organic phases were dried over MgSCU and the solvent was removed under reduced pressure. The crude product was used into the next step without further purification. Compound 2 (150 g, crude) was obtained as a yellow oil.

[0780] 'H NMR (400 MHz, CHLOROFORM-d) 5 = 7.41 - 7.35 (m, 5H), 5.79 (d, J = 3.8 Hz, 1H), 4.88 (d, J = 12.0 Hz, 1H), 4.77 (d, J = 11.6 Hz, 1H), 4.68 - 4.63 (m, 1H), 4.57 (d,J = 11.6 Hz, 1H), 4.41 (d, J= 12.0 Hz, 1H), 4.32 (d, J = 11.0 Hz, 1H), 4.22 - 4.12 (m, 2H), 3.08 (s, 3H), 2.98 (s, 3H), 1.68 (s, 3H), 1.34 (s, 3H)

[0781] LCMS (M+Na+): 489

[0782] 4. Preparation of compound 3:

[0783]

[0784] 2 3

[0785] To a solution of compound 2 (50 g, 107.18 mmol) was added TFA (250 mL) and H2O (62.5 mL). The mixture was stirred at 20°C for 12 hr. LCMS showed compound 2 was consumed completely and desired mass was detected. The reaction mixture was concentrated under reduced pressure to remove TFA. The residue was diluted with NaHCCh (500 mL) and extracted with DCM (300 mL*2). The combined organic layers were washed with brine 500 mL, dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The crude product was used into the next step without further purification. Compound 3 (137 g, crude) was obtained as a yellow oil.

[0786] 1H NMR (400 MHz, CHLOROFORM-d) 5 = 8.64 (br d, J = 4.6 Hz, 1H), 7.48 - 7.45 (m, 1H), 7.41 - 7.30 (m, 5H), 5.39 - 5.34 (m, 1H), 4.66 - 4.59 (m, 2H), 4.35 -4.33 (m, 1H), 4.31 - 4.20 (m, 1H), 4.19 - 4.14 (m, 1H), 4.11 (d, J = 5.0 Hz, 1H), 3.05 - 2.97 (m, 6H) LCMS (M+Na+): 449.1

[0787] 5. Preparation of compound 4:

[0788]

[0789] 3 4

[0790] To a solution of compound 3 (65 g, 152.42 mmol) in pyridine (600 mL) was added AC2O (57.57 g, 563.95 mmol). The mixture was stirred at 20°C for 12 hr. LCMS showed compound 3 was consumed completely and desired mass was detected. The reaction mixture was diluted with NaHCOs (1000 mL) and extracted with EtO Ac (500 mL*2). The combined organic layers were washed with brine 800 mL, dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by columnchromatography (SiCL, petroleum ether: ethyl acetate = 0:1 to 1:1). Compound 4 (155 g, crude) was obtained as a yellow oil.

[0791] ‘HNMR (400 MHz, CHLOROFORM-d) 5 = 7.42 - 7.33 (m, 5H), 6.18 (s, 1H), 5.38 (d, J = 4.8 Hz, 1H), 4.65 - 4.60 (m, 1H), 4.55 - 4.48 (m, 2H), 4.43 (d, J = 4.8 Hz, 1H), 4.31 - 4.28 (m, 1H), 4.23 - 4.17 (m, 2H), 3.02 (d, J = 2.0 Hz, 6H), 2.16 (s, 3H), 2.11 (s, 3H) LCMS (M+Na+): 533.1

[0792] TLC: Petroleum ether: Ethyl acetate = 1:1, Rf = 0.5

[0793] 6. Preparation of compound 5:

[0794]

[0795] To a solution of compound 4 (50 g, 97.94 mmol) and uracil (21.95 g, 195.87 mmol) in ACN (700 mL) was added BSA (69.73 g, 342.78 mmol) at 80 °C for 1 hr. Then TMSOTf (54.42 g, 244.84 mmol) was added to the mixture. The mixture was stirred at 60°C for 12 hr. LCMS showed compound 4 was consumed completely and desired mass was detected. The reaction mixture was cooled to 0°C, and added to NaHCO3 (800 mL). The residue was extracted with EtOAc (500 mL*3). The combined organic layers were washed with brine 500 mL, dried over Na₂SO₄, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, petroleum ether: ethyl acetate = 1:0 to 0: 1). Compound 5 (78 g, 47.27% yield) and 78 g (crude) was obtained as a white solid.

[0796] 'HNMR (400 MHz, DMSO-d6) 5 = 11.46 (br s, 1H), 7.71 (d, J = 8.0 Hz, 1H), 7.39 - 7.29 (m, 5H), 5.98 (d, J = 4.6 Hz, 1H), 5.68 (d, J = 8.0 Hz, 1H), 5.55 - 5.50 (m, 1H), 4.65 - 4.53 (m, 3H), 4.45 - 4.37 (m, 3H), 4.36 - 4.30 (m, 1H), 3.26 (s, 3H), 3.19 (s, 3H), 2.05 (s, 3H)

[0797] LCMS (M+Na+): 585.1, purity: 92.5%

[0798] TLC: Petroleum ether: Ethyl acetate = 0:1, Rf = 0.5

[0799] 7. Preparation of compound 6:

[0800]

[0801] To a solution of compound 5 (41.5 g, 73.77 mmol) in dioxane (100 mL) and H2O (100 mL) was added NaOH (2 M, 221.31 mL). The mixture was stirred at 20°C for 12 hr. LCMS showed compound 5 was consumed completely and one main peak with desired mass was detected. The reaction mixture was washed with 10% AcOH (300 mL). The residue was diluted with H2O (500 mL) and extracted with DCM (300 mL*3). The combined organic layers were washed with NaHCO3 (200 mL) and brine (200 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The crude product was triturated with EtOAc at 20°C for 5 min. The mixture was filtered and the cake was concentrated under reduced pressure to give product. Compound 6 (50 g, 79.85% yield) was obtained as a white solid.

[0802] 'HNMR (400 MHz, DMSO-d6) 5 = 11.42 (br s, 1H), 7.62 (d, J = 8.0 Hz, 1H), 7.37 - 7.25 (m, 5H), 5.60 (d, J = 8.0 Hz, 1H), 5.56 (s, 1H), 4.83 (d, J = 12.0 Hz, 1H), 4.63 (d, J = 3.0 Hz, 2H), 4.61 - 4.56 (m, 2H), 4.03 - 3.97 (m, 2H), 3.84 (d, J = 8.0 Hz, 1H), 3.27 (s, 3H) LCMS (M+H+): 425.0, purity: 92.4%

[0803] TLC: Petroleum ether: Ethyl acetate = 0:1 Rf = 0.4

[0804] 8. Preparation of compound 7:

[0805]

[0806] To a solution of compound 6 (20 g, 47.12 mmol) in DMF (200 mL) was added NaNs (3.17 g, 48.76 mmol). The mixture was stirred at 60°C for 12 hr. LCMS showed compound 6 was consumed completely and desired mass was detected. The reaction was quenched by H2O (100 mL), and extracted with Ethyl acetate (200 mL*3). The combined organic was dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. Thecrude product was triturated with petroleum ether: ethyl acetate = 10:1, at 20°C for 5 min. Then the mixture was filtered, the cake was washed with Petroleum ether, concentrated under reduced pressure to give product. Compound 7 (15.5 g, 88.58% yield) was obtained as a white solid.

[0807] 'HNMR (400 MHz, DMSO-d6) 5 = 11.42 (s, 1H), 7.60 (d, J = 8.2 Hz, 1H), 7.37 -7.27 (m, 5H), 5.65 (d, J = 8.2 Hz, 1H), 5.54 (s, 1H), 4.66 - 4.57 (m, 2H), 4.54 (s, 1H), 4.01 (d, J = 14.0 Hz, 1H), 3.94 - 3.89 (m, 2H), 3.87 - 3.77 (m, 2H)

[0808] LCMS (M+H+): 372.0

[0809] 9. Preparation of compound 8:

[0810]

[0811] To a solution of compound 7 (10 g, 26.93 mmol) and compound 5A (10.80 g, 32.31 mmol) in THF (100 mL) and H2O (100 mL) was added copper; sulfate; pentahydrate (8.07 g, 32.31 mmol) and sodium; (2R)-2-[(1S)-1,2-dihydroxyethyl]-4-hydroxy-5-oxo-2H-furan-3-olate (6.40 g, 32.31 mmol). The mixture was stirred at 65°C for 6 hr. TLC indicated compound 7 was consumed completely and one new spot formed. The reaction mixture was concentrated under reduced pressure to remove THF. The residue was diluted with H2O (50 mL) and extracted with EtOAc (100 mL*2). The combined organic layers were dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, petroleum ether: ethyl acetate = 1:0 to 0: 1). Compound 8 (18 g, 94.72% yield) was obtained as a white solid.

[0812] 1H NMR (400 MHz, DMSO-d6) 5 =11.39 (s, 1H), 8.78 (s, 1H), 7.36 (d, J = 4.2 Hz, 4H), 7.33 - 7.26 (m, 2H), 5.73 (s, 2H), 5.69 (s, 2H), 5.52 (br d, J = 8.0 Hz, 1H), 5.47 (s, 1H), 5.28 (br d, J = 15.0 Hz, 1H), 5.02 (br d, J = 15.0 Hz, 1H), 4.66 (s, 2H), 4.57 (s, 1H), 4.11 (d, J = 8.0 Hz, 1H), 3.58 (br d, J = 8.2 Hz, 2H), 1.10 (s, 18H)

[0813] 31P NMR (162 MHz, DMSO-d6) 5 = 6.73 (s, IP)

[0814] LCMS (M+H+): 706.3, purity: 94.7%

[0815] TLC: Petroleum ether: Ethyl acetate = 0:1, Rf = 0.310. Preparation of WV-NU-349:

[0816]

[0817] 2,-LNA-5'-PO(POM)2-Triazolyl Phosphonate Uridine (WV-NU-349) To a solution of compound 8 (9 g, 12.75 mmol) in AcOH (100 mL) was added Pd / C (1.36 g, 1.28 mmol, 10% purity). The mixture was stirred at 30°C for 12 hr under H2 (15 Psi). LCMS showed compound 8 was consumed completely and desired mass was detected. The reaction mixture was filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 1:0 to 0:1, ethyl acetate: methanol = 1:0 to 10:1). Compound WV-NU-349 (7.49 g, 49.93% yield) was obtained as a white solid.

[0818] ‘HNMR (400 MHz, DMSO-d6) 5 = 11.38 (s, 1H), 8.78 (s, 1H), 7.29 (d, J = 8.0 Hz, 1H), 6.11 (br d, J = 4.0 Hz, 1H), 5.72 (br d, J = 13.8 Hz, 3H), 5.51 (d, J = 8.0 Hz, 1H), 5.39 (s, 1H), 5.22 (d, J = 15.0 Hz, 1H), 4.96 (d, J = 15.0 Hz, 1H), 4.25 (s, 1H), 4.07 (d, J = 8.0 Hz, 1H), 3.86 (d, J = 3.6 Hz, 1H), 3.50 (d, J = 8.0 Hz, 1H), 1.11 (s, 18H)

[0819] 31P NMR (162 MHz, DMSO-d6) 8 = 6.75 (s, IP)

[0820] LCMS (M-H+): 616.2, purity: 98.88%

[0821] TLC: Ethyl acetate: Methanol = 10:l, Rf= 0.3

[0822] EXAMPLE 9. Synthesis of WV-NU-350

[0823]

[0824] WV-NU-350

[0825] 2,-OMe-5'-PS(OEt)2-Triazolyl Thiophosphonate Uridine (WV-NU-350) O, O-di ethyl (l-(((2R,3R,4R,5R)-5-(2,4-dioxo-3,4-dihydropyrimidin-l(2H)-yl)-3-hydroxy- 4-methoxytetrahydrofuran-2-yl)methyl)-lH-l,2,3-triazol-4-yl)phosphonothioateGeneral Scheme:

[0826] S

[0827]

[0828] WV-NU-350

[0829] Experimental Procedure:

[0830] / . Preparation of compound 2A:

[0831]

[0832] To a solution of compound 1A (9.3 g, 59.41 mmol) in THF (100 mL) was added bromo (ethynyl) magnesium (0.5 M, 120.00 mL) at 0°C under N2. The resulting mixture was stirred at 0-15°C for 2 hr. TLC indicated compound 1 A was consumed completely and two new spots formed. The reaction was clean according to TLC. The mixture was quenched by addition sat. NH4CI (aq. 150 mL) at 0 °C, then diluted with H2O (100 mL) and extracted with DCM (200 mL*3). The combined organic layers were dried over Na2SO4, filtered to get the crude. Without purification. Compound 2A (26 g, crude) was obtained as a brown oil.

[0833] TLC: petroleum ether: ethyl acetate = 1:1, Rf = 0.952. Preparation of compound 3 A:

[0834]

[0835] To a solution of compound 2A (13 g, 88.97 mmol) in DCM (150 mL) was added S (5.40 g, 168.41 mmol). The mixture was stirred at 15°C for 2 hr. TLC indicated compound 2A was consumed completely and one new spot formed. The reaction was clean according to TLC. The reaction mixture was cooled to 0°C and quenched by addition H2O 80 mL, and then diluted with H2O 50 mL and extracted with DCM 150 mL (50 mL*3). The combined organic layers were dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, petroleum ether: ethyl acetate = 1:0 to 0:1). Compound 3 A (14 g, 44.16% yield) was obtained as a yellow oil.

[0836] 'H NMR (400 MHz, CHLOROFORM-d) 5 = 4.16 (qd, J = 7.2, 10.3 Hz, 4H), 3.12 (d, J = 12.4 Hz, 1H), 1.34 (t, J = 7.2 Hz, 6H)

[0837] 31P NMR (162 MHz, CHLOROFORM-d) 5 = 51.30 (s, IP)

[0838] LCMS (M+H+): 179.1

[0839] TLC: Petroleum ether: Ethyl acetate = 5:1, Rf = 0.7

[0840] 3. Preparation of compound 2:

[0841]

[0842] To a solution of compound 1 (30 g, 116.18 mmol) in THF (420 mL) was added imidazole (20.56 g, 302.06 mmol), I2(47.18 g, 185.88 mmol) and PPh3(48.75 g, 185.88 mmol) at 0°C. The mixture was stirred at 25°C for 6 hr. TLC indicated compound 1 was consumed completely and two new spots formed. The reaction was clean according to TLC. The reaction was quenched by 10% aqueous sodium thiosulfate solution (800 ml). After removing the solvent and volatiles under reduced pressure, the residue was extracted intoDichloromethane (200 mL*3) and washed with saturated aqueous NaHCO3 solution. The organic layer was separated, dried over anhydrous Na₂SO₄U, filtered and concentrated. The residue was purified by column chromatography (SiCL, petroleum ether: ethyl acetate = 1:0 to 0:1 to dichloromethane: methanol = 1:0 to 3:1). The crude product was purified by recrystallization from ethyl acetate (100 mL), di chloromethane (300 mL) and methanol (50 mL) at 15 °C. Compound 2 (200 g, 93.55% yield) was obtained as a purple solid.

[0843] ’H NMR (400 MHz, DMSO-d6) 5 = 11.43 (s, 1H), 7.68 (d, J = 8.2 Hz, 1H), 5.87 (d, J = 5.6 Hz, 1H), 5.70-5.68 (m, 1H), 5.46 (d, J = 6.0 Hz, 1H), 4.05-4.01 (m, 1H), 4.00-3.95 (m, 1H), 3.88-3.82 (m, 1H), 3.54-3.53 (m, 1H), 3.42-3.40 (m, 1H), 3.34 (s, 3H) LCMS (M+H+): 369.0

[0844] TLC: di chloromethane: methanol = 10:1, Rf = 0.45

[0845] 4. Preparation of compound 3:

[0846]

[0847] To a solution of compound 2 (24 g, 65.20 mmol) in 1, 2-dimethoxyethane (300 mL) and H2O (60 mL) was added NaN3 (3.66 g, 56.30 mmol) at 0°C under N2. The mixture was stirred at 90°C for 12 hr. LCMS showed compound 2 was remained and the desired mass was detected. The reaction was quenched by H2O (500 mL), and extracted with ethyl acetate (400 mL*3). The combined organic layers were washed with saturated aqueous NaCl 300 mL, dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, petroleum ether: ethyl acetate = 1:0 to 0:1). The crude product was triturated with Ethyl acetate (50 mL) at 15°C for 10 min. Compound 3 (49 g, 85.51% yield) was obtained as a white solid.

[0848] 1HNMR(400 MHz, DMSO-d6) 5 = 11.48 - 10.91 (m, 1H), 7.70 (d, J = 8.2 Hz, 1H), 5.83 (d, J = 4.8 Hz, 1H), 5.68 (d, J = 8.0 Hz, 1H), 5.36 (br d, J = 5.8 Hz, 1H), 4.07 (q, J = 5.2 Hz, 1H), 3.95 - 3.89 (m, 2H), 3.61 (d, J = 4.8 Hz, 2H), 3.36 (s, 3H)

[0849] LCMS: (M+H+): 284.0, purity: 90.16%

[0850] TLC: di chloromethane: methanol = 10:1, Rf = 0.455. Preparation of WV-NU-350:

[0851]

[0852] 3 WV-NU-350

[0853] 2'-OMe-5'-PS(OEt)2-Triazolyl Thiophosphonate Uridine (WV-NU-350) To a solution of compound 3 (8 g, 28.24 mmol) and compound 3 A (5.54 g, 31.07 mmol) in THF (80 mL) was degassed and purged with N2 for 3 times, then DIEA (7.30 g, 56.49 mmol), Cui (10.76 g, 56.49 mmol) was added. The mixture was stirred at 20°C for 4 hr under N2 atmosphere. LCMS showed compound 3 was remained and the desired mass was detected. The reaction mixture was concentrated under reduced pressure to give product. The residue was purified by column chromatography (SiCh, petroleum ether: ethyl acetate = 1:0 to 0:1). Compound WV-NU-350 (10 g, 76.92% yield) was obtained as a yellow solid.

[0854] 1HNMR(400 MHz, DMSO-d6) 5 = 11.41 (d, J = 1.6 Hz, 1H), 8.58 (s, 1H), 7.53 (d, J = 8.2 Hz, 1H), 5.80 (d, J = 4.8 Hz, 1H), 5.64 - 5.62 (m, 1H), 5.49 (d, J = 6.2 Hz, 1H), 4.84 - 4.78 (m, 1H), 4.77 - 4.69 (m, 1H), 4.21 (td, J = 4.8, 7.8 Hz, 1H), 4.17 - 4.07 (m, 5H), 3.91 (t, J = 5.2 Hz, 1H), 3.36 (s, 3H), 1.24 (t, J = 7.0 Hz, 6H)

[0855] 31P NMR (162 MHz, DMSO-d6) 5 = 69.85 (s, IP)

[0856] LCMS (M+H+): 462.1, purity: 98.75%

[0857] TLC: Petroleum ether: Ethyl acetate = 0:1, Rf = 0.25

[0858] EXAMPLE 10. Synthesis of WV-NU-352

[0859]

[0860] WV-NU-352

[0861] 2,-OMe-5'-PO(OEt)2-Triazolyl methyl phosphonate Uridine (WV-NU-352) Diethyl ((4-((2R,3R,4R,5R)-5-(2,4-dioxo-3,4-dihydropyrimidin-l(2H)-yl)-3-hydroxy-4- methoxytetrahydrofuran-2-yl)-lH-l,2,3-triazol-l-yl)methyl)phosphonate General Scheme:

[0862]

[0863] Experimental Procedure:

[0864] 1. Preparation of compound 2:

[0865]

[0866] To a solution of compound 1 (50 g, 193.63 mmol) in DMF (1000 mL) was added imidazole (52.73 g, 774.51 mmol) and TBSCI (87.55 g, 580.88 mmol). The mixture was stirred at 20°C for 12 hr. TLC indicated compound 1 was consumed completely and one new spot formed. The reaction mixture was concentrated under reduced pressure to remove DMF. The residue was diluted with H2O 1500 mL and extracted with EtOAc (500 mL*3). The combined organic layers were washed with brine 1500 mL, dried over Na₂SO₄, filtered and concentrated under reduced pressure to give a residue. Compound 2 (188 g, crude) was obtained as a colorless oil.

[0867] TLC: Petroleum ether: Ethyl acetate = 0:1, Rf = 0.7

[0868] 2. Preparation of compound 3:

[0869]

[0870] To a solution of compound 2 (94 g, 193.12 mmol) in THF (1000 mL) at 0°C under N2, and then added mixture of TFA (383.75 g, 3.37 mol) and H2O (250.00 g, 13.88 mol) slowly. The mixture was stirred at 0°C for 3 hr. TLC indicated compound 2 was consumed completely and one new spot formed. The reaction mixture was quenched with NH3. H2O (230 mL*4) at 0°C. The residue was diluted with H2O 500 mL and extracted with DCM (1000 mL*3). The combined organic layers were washed with brine 1000 mL, dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, petroleum ether: ethyl acetate = 1:0 to 0:1). Compound 3 (230 g, 79.93% yield) was obtained as a white solid.

[0871] ‘HNMR (400 MHz, DMSO-d6) 5 = 11.36 (s, 1H), 7.92 (d, J = 8.0 Hz, 1H), 5.83 (d, J = 5.0 Hz, 1H), 5.66 (d, J = 8.0 Hz, 1H), 5.21 (t, J = 5.0 Hz, 1H), 4.30 (t, J = 4.8 Hz, 1H), 3.87 - 3.81 (m, 2H), 3.70 - 3.61 (m, 1H), 3.55 – 3.51 (m, 1H), 3.34 (s, 3H), 0.88 (s, 9H), 0.09 (s, 6H)LCMS (M+H+): 373.1, purity: 100%

[0872] TLC: Petroleum ether: Ethyl acetate = 0:1, Rf = 0.6

[0873] 3. Preparation of compound 4:

[0874]

[0875] 3 4

[0876] To a solution of compound 3 (25 g, 67.12 mmol) in DCM (500 mL) was added DMP (28.47 g, 67.12 mmol). The mixture was stirred at 0-25°C for 3 hr. TLC indicated compound 3 was consumed completely and one new spot formed. The reaction mixture of three batches were diluted with NaHCCf 500 mL and extracted with DCM (500 mL*3). The combined organic layers were washed with Sat. NaCl 100 mL, dried over Na2SO4, filtered and concentrated under reduced pressure to get crude product. The crude product was used into the next step without further purification. Compound 4 (24 g, crude) was obtained as a white solid.

[0877] 1H NMR (400 MHz, DMSO-d6) 5 = 11.59 - 11.25 (m, 1H), 7.92 - 7.89 (m, 1H), 5.94 (d, J = 7.7 Hz, 1H), 5.73 - 5.68 (m, 1H), 4.90 (d, J = 3.0 Hz, 1H), 4.46 (d, J = 4.6 Hz, 1H), 3.87 - 3.85 (m, 1H), 3.72 (d, J = 2.6 Hz, 1H), 3.61 - 3.58 (m, 3H), 0.90 - 0.88 (m, 9H), 0.10 (s, 6H)

[0878] TLC: Petroleum ether: Ethyl acetate = 0:1, Rf = 0.45

[0879]

[0880] To a solution of compound 4 (22 g, 59.38 mmol) and 1-diazo-l-dimethoxyphosphoryl-propan-2-one (11.41 g, 59.38 mmol) in MeOH (400 mL) was added K2CO3 (16.41 g, 118.77 mmol) at 0°C under N2. The mixture was stirred at 0-20°C for 12 hr. LCMS showed compound 4 was consumed completely and one main peak with desiredmass was detected. The reaction mixture was concentrated under reduced pressure to remove MeOH. The residue was diluted with H2O 300 mL and extracted with DCM (200 mL*3). The combined organic layers were dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCh, petroleum ether: ethyl acetate = 1:0 to 0:1). Compound 5 (25 g, 57.44% yield) was obtained as a white solid.

[0881] H NMR (400 MHz, DMSO-d6) 6 = 11.43 (s, 1H), 7.58 (d, J = 8.2 Hz, 1H), 5.82 (d, J = 4.4 Hz, 1H), 5.75 (d, J = 8.0 Hz, 1H), 4.49 - 4.46 (m, 1H), 4.44 (d, J = 4.6 Hz, 1H), 4.04 - 4.01 (m, 1H), 3.87 (d, J = 1.4 Hz, 1H), 3.36 (s, 3H), 0.89 (s, 9H), 0.13 (d, J = 3.2 Hz, 6H) LCMS (M-H+):367.1; purity: 95.3%

[0882] TLC: Petroleum ether: Ethyl acetate = 1: 1, Rf = 0.4

[0883] 5. Preparation of compound 2A:

[0884]

[0885] 1A 2A

[0886] To a solution of compound 1A (30 g, 107.90 mmol) in DMF (300 mL) was added NaN3 (7.27 g, 111.83 mmol. The mixture was stirred at 90°C for 12hr. TLC indicated compound 1A was consumed completely and one new spot formed. The reaction was cooled to 0°C, and quenched by H2O (300 mL), and extracted with Ethyl acetate (200 mL*3). The combined organic dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCh, petroleum ether: ethyl acetate = 1:0 to 0:1). Compound 2A (12 g, 57.58% yield) was obtained as a colorless oil.

[0887] .25 - 4.14 (m, 4H), 3.46 (d, J = 11.8 Hz, 1H),

[0888]

[0889] TLC: Petroleum ether: Ethyl acetate = 0:l, Rf= 0.25

[0890] 6. Preparation of compound 6:

[0891]

[0892] To a solution of compound 5 (10 g, 27.29 mmol) and compound 2A (6.85 g, 35.47 mmol) in THF (50 mL) and H2O (50 mL) was added copper; sulfate; pentahydrate (8.18 g, 32.74 mmol) and sodium; (2R)-2-[(1S)-1,2-dihydroxyethyl]-4-hydroxy-5-oxo-2H-furan-3-olate (6.49 g, 32.74 mmol). The mixture was stirred at 65°C for 6 hr. TLC indicated compound 5 was consumed completely and one new spot formed. The reaction mixture was concentrated under reduced pressure to remove THF. The residue was diluted with H2O 100 mL and extracted with EtOAc (100 mL*2). The combined organic layers were washed with brine 100 mL, dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, petroleum ether: ethyl acetate = 1:0 to 0: 1). Compound 6 (9.7 g, 63.52% yield) was obtained as a white solid.

[0893] 'HNMR (400 MHz, DMSO-d6) 5 = 11.42 (s, 1H), 8.21 (s, 1H), 7.95 (d, J = 8.0 Hz, 1H), 5.90 (d, J = 3.4 Hz, 1H), 5.72 - 5.69 (m, 1H), 5.12 (br d, J = 13.0 Hz, 2H), 5.01 (d, J = 6.0 Hz, 1H), 4.60 -4.54 (m, 1H), 4.12 - 4.03 (m, 5H), 3.43 (s, 3H), 1.24 - 1.18 (m, 6H), 0.80 (s, 9H), 0.00 (s, 3H), -0.11 (s, 3H)

[0894] 31P NMR (162 MHz, DMS0-d6) 5 = 17.19 (s, IP)

[0895] LCMS (M-H+):560.3; purity: 96.99%

[0896] TLC: Petroleum ether: Ethyl acetate = 0:1, Rf = 0.3

[0897] 7. Preparation of compound WV-NU-352:

[0898]

[0899] WV-NU-352

[0900] 2'-OMe-5'-PO(OEt)2-Triazolyl methyl phosphorate Uridine (WV-NU-352)To a solution of compound 6 (9 g, 16.08 mmol) in THF (95 mL) was added N, N-diethylethanamine; trihydrofluoride (10.37 g, 64.33 mmol). The mixture was stirred at 40°C for 12 hr. TLC indicated compound 6 was consumed completely and one new spot formed. The reaction mixture was concentrated under reduced pressure to remove THF. The residue was purified by column chromatography (SiCh, petroleum ether: ethyl acetate = 1:0 to 0:1, ethyl acetate: methanol = 1:0 to 5:1). Compound WV-NU-352 (4.3 g, 60.04% yield) was obtained as a white solid.

[0901] 'HNMR (400 MHz, DMSO-d6) 5 = 11.41 (br s, 1H), 8.18 (s, 1H), 7.89 - 7.87 (m, 1H), 5.96 (d, J = 3.8 Hz, 1H), 5.69 (d, J = 8.0 Hz, 1H), 5.54 -5.52 (m, 1H), 5.11 (br d, J = 13.0 Hz, 2H), 5.01 (d, J = 4.6 Hz, 1H), 4.40 (q, J = 5.0 Hz, 1H), 4.12 - 4.01 (m, 5H), 3.42 (d, J = 1.0 Hz, 3H), 1.21 (t, J = 7.0 Hz, 6H)

[0902] 31P NMR (162 MHz, DMSO-d6) 5 = 17.28 (s, IP)

[0903] LCMS (M-H+): 446.1; purity: 96.79%

[0904] TLC: Ethyl acetate: Methanol = 8:l, Rf= 0.25

[0905] EXAMPLE 11. Synthesis of WV-NU-362

[0906]

[0907] 2'-OMe-5'-(3-PO(OEt)2-pyrrolidinyl) phosphonate Uridine (WV-NU-362) diethyl (1 -(((2R,3R,4R,5R)-5-(2,4-dioxo-3,4-dihydropyrimidin-1 (2 / 7)-yl)-3-hydroxy-4- methoxytetrahydrofuran-2-yl)methyl)pyrrolidin-3-yl)phosphonate (WV-NU-362) General Scheme:

[0908]

[0909] To a stirred solution of N-benzyl-l-methoxy-N-((trimethylsilyl)methyl) methenamine (12 g, 0.05063 mol) and diethyl vinylphosphonate (8.3 g, 0.05063) in dry ACN (120 mL, 10 vol), was added TFA (3.9 mL, 0.0563 mol) dropwise over a period for 10 min at 0°C. The resulting mixture was stirred at rt for 6 h. Progress of the reaction was monitored by TLC. Then reaction mixture was concentrated under reduced pressure. The crude compound was purified by column chromatography over silica-gel (230-400 mesh) eluted in 40% acetone in hexane to get a yellow oil (WV-NU-362-A) (6 g, 40%).

[0910] TLC mobile phase details: 50% acetone in hexane

[0911] 'H NMR (400 MHz, CDC13): 8 in ppm = 7.30 (m, 4H), 7.25 (m, 1H), 4.10 (m, 4H), 3.63 (s, 2H), 2.98 (m, 1H), 2.83 (m, 1H), 2.49 (m, 3H), 2.11 (m, 2H), 1.31 (t, 6H, JI = 7.1 Hz).MS: m / z calcd for C15H24NO3P, 297.3; found 298.52, [M+H]

[0912] Preparation of diethyl pyrrolidin-3-ylphosphonate (WV-NU-362-B):

[0913]

[0914] WV-NU-362-B

[0915] To a stirred solution of (WV-NU-362-A) (6 g, 0.02289 mol) in dry MeOH (120 mL, 20 vol) was added Ammonium formate (2.16 g, 0.03434 mol) and Pd / C (1.8 g, 30 mol %) portion wise at rt. The resulting mixture was stirred 40°C and kept for 1.5 h. Progress of the reaction was monitored by TLC. After completion as monitored by TLC, the reaction mixture was filtered through celite bed, washed with MeOH (2 x 50 mL) and concentrated under reduced pressure to afford light yellow oil (WV-NU-362-B) (3.2 g, crude).

[0916] TLC Mobile phase details: 10% MeOH in DCM.

[0917] 1H NMR (400 MHz, CDCI3): 8 in ppm = 4.12 (m, 4H), 3.44 (s, 2H), 3.13 (m, 2H), 2.91 (m, 1H), 2.36 (m, 1H), 2.01 (m, 2H), 1.33 (t, 6H, JI = 7.1 Hz)

[0918] MS: m / z calcd for C8H18NO3P, 207.2; found 208.24 [M-H]+

[0919] Preparation of (2S, 3S, 4R, 5R)-3-((tert-butyldimethylsilyl) oxy)-5- (2, 4-dioxo-3, 4-dihydro pyrinudin-l(2H)-yl)-4-niethoxytetrahydrofuran-2-carbaldehyde (WV-NU-362-02):

[0920]

[0921] WV-NU-362-02

[0922] To a stirred solution of (WV-NU-362-01) (5 g, 0.0134 mol) in dry DCM (125 mL, 25 vol) was added Dess-Martin Periodinane (7.4 g, 0.0174 mol) portion wise over a period of 20 min at 0°C. The reaction mixture was allowed to stir at rt for 2.5 h. Progress of the reaction was monitored by TLC. After completion, the reaction was quenched with a solution (1:1 ratio of Na2S20s: NaHCCh (80 mL), extracted with DCM (2 x 60 mL), dried over Na2SO4 and concentrated under reduced pressure to afford off white solid (WV-NU-362-02) (4.6 g, crude).

[0923] TLC mobile phase details: 70% EtOAc in hexane

[0924] 'HNMR (500 MHz, CDC13): 8 in ppm = 9.78 (s, 1H), 8.58 (s, 1H), 7.63 (d, 1H, JI = 7.6 Hz), 5.80 (t, 2H, JI = 5.9 Hz), 4.54 (d, 1H, JI = 4.1 Hz), 4.43 (t, 1H, JI = 4.1 Hz), 3.93 (t, 1H, JI = 4.8 Hz), 3.46 (m, 4H), 0.92 (m, 9H), 0.12 (m, 8H)

[0925] MS: m / z calcd for Ci6H26N2O6Si, 370.05; found 371.32. [M-H]+

[0926] Preparation of diethyl (l-(((2R,3R,4R,5R)-3-((tert-butyldimethylsilyl)oxy)-5-(2,4-dioxo-3,4-dihydropyrinudin-l(2H)-yl)-4-methoxytetrahydrofuran-2-yl)methyl)pyrrolidin3yl)phosphonate (WV-NU-362-03):

[0927]

[0928] WV-NU-362-03

[0929] To a stirred solution of (WV-NU-362-B) (9 g, 0.0434 mol) in dry DCM (225 mL, 25 vol), (WV-NU-362-02) (15 g, 0.04086 mol) at rt. was added Na (OAc)3BH (8.9 g, 0.06173 mol) portion wise over a period of 10 min, at 0°C. Then reaction mixture was stirred to 20°C for 8 h. Progress of the reaction was monitored by TLC. The reaction was quenched with saturated aqueous NaHCCh (50 mL) at 0°C and extracted with DCM (2 x 100 mL), dried over Na2SO4 and concentrated under reduced pressure to afford light yellow semi syrup. (WV-NU-362-03) (14.6 g, crude).

[0930] TLC Mobile phase details: 10% MeOH in DCM

[0931] 'H NMR (500 MHz, CDCI3): 6 in ppm = 9.32 (s, 1H), 7.56 (dd, 1H, JI = 45.4 Hz,.72 = 7.6 Hz), 5.81 (m, 1H), 5.72 (m, 1H), 4.11 (m, 6H), 3.96 (m, 1H), 3.64 (td, 1H, JI = 5.9 Hz, J2 = 1.4 Hz), 3.51 (m, 3H), 3.38 (m, 1H), 3.00 (m, 2H), 2.79 (m, 2H), 2.55 (m, 3H), 2.05 (m, 2H), 1.31 (m, 7H), 0.91 (td, 11H, JI = 6.7 Hz, J2 = 3.7 Hz), 0.79 (m, 6H) MS: m / z calcd for C24H44N3O8PSi, 561.7; found 362-59. [M-H]+

[0932] Preparation of diethyl (l-(((2R,3R,4R,5R)-5-(2,4-dioxo-3,4-dihydropyrinudin-l(2H)-yl)-3-hydroxy-4-niethoxytetrahydrofuran-2-yl)methyl)pyrroHdin-3-yl)phosphonate (WV-NU-362):

[0933]

[0934] WV-NU-362

[0935] 2'-OMe-5'-PO(OEt)2-Pyrrolidinyl phosphonate Uridine (WV-NU-362)

[0936] To a stirred solution of (WV-NU-362-03) (14.6 g, 0.0260 mol) in H2O (73 mL, 5 vol), was added formic acid (73 mL, 5 vol) at 0°C. Then the reaction mixture was allowed to stir at rt for 24 h. Progress of the reaction was monitored by TLC. After completion, the reaction mixture was concentrated under reduced pressure and the crude mass was codistilled with toluene (50 ml x3). The crude compound was purified by column chromatography over silica-gel (230-400 mesh) eluted in 6% MeOH in DCM to afford brown solid (WV-NU-362) (6.6 g, 56%).

[0937] TLC Mobile phase details: 10% MeOH in DCM

[0938] 1H NMR (500 MHz, D2O): 5 in ppm = 7.65 (d, 1H, JI = 8.3 Hz), 5.87 (t, 2H, JI = 3.4 Hz), 4.16 (m, 6H), 4.07 (q, 1H, JI = 3.7 Hz), 3.49 (s, 3H), 3.32 (m, 1H), 3.06 (m, 3H), 2.76 (m, 3H), 2.18 (d, 1H, JI = 7.6 Hz), 2.06 (dt, 1H JI = 14.0 Hz, J2 = 6.0 Hz), 1.31 (m, 6H)

[0939] MS: m / z calcd for C18H30N3O8P, 447.4; found 449.7. [M-H]+

[0940] EXAMPLE 12. Synthesis of WV-NU-343

[0941]

[0942] WV-NU-343 2'-OMe-5'-PO(OEt)2-1,5-Triazolyl Phosphonate Uridine (WV-NU-343) Diethyl (l-(((2R,3R,4R,5R)-5-(2,4-dioxo-3,4-dihydropyrimidin-l(2H)-yl)-3-hydroxy-4- methoxytetrahydrofuran-2-yl)methyl)- 1H- 1,2,3-triazol-5-yl)phosphonateGeneral Scheme:

[0943]

[0944] Experimental Procedure:

[0945] 1. Preparation of compound 2A:

[0946] OEt& MgBrOEt

[0947] Cl— R - ►

[0948] OEtTHF

[0949]

[0950] 0Et

[0951] 0-15 °C, 2 h

[0952] 1A 2A

[0953] To a solution of compound 1A (11 g, 70.27 mmol) in THF (150 mL) was added bromo (ethynyl) magnesium (0.5 M, 140.53 mL) at 0°C under N2. The resulting mixture was stirred at 15°C for 2 hr. TLC indicated compound 1A was consumed completely and two new spots formed. The reaction was clean according to TLC. The reaction mixture was quenched by sat. aq. NFLCl (150 mL) at 0°C, then extracted with DCM (100 mL*3). The combined organic layers were dried over Na2SO4, filtered to get the crude. Without purification. Compound 2A (1.87 g, crude) was obtained as a brown oil.

[0954] TLC: Petroleum ether: Ethyl acetate = 1:1, Rf = 0.95

[0955] 2. Prep2. Preparation of compound 3A:

[0956]

[0957] 2A 3A

[0958] To a solution of compound 2A (16 g, 109.50 mmol) in DCM (400 mL) was added m-CPBA (44.46 g, 218.99 mmol) at 0°C. The mixture was stirred at 0-15°C for 2 hr. TLC indicated compound 2A was consumed completely and two new spots formed. The reaction was clean according to TLC. The reaction mixture was quenched by sat. aq. Na2SO3(300 mL) and NaHCO3(300mL), then extracted with DCM (200 mL*3). The combined organic layers were washed with brine (100 mL*2), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 1:0 to 0:1). Compound 3 A (35 g, 50.72% yield) was obtained as a yellow oil.

[0959] 1H NMR (400 MHz, CHLOROFORM-d) 5 = 4.17 (quin, J = 7.6 Hz, 4H), 2.92 (d, J = 13.4 Hz, 1H), 1.36 (t, J = 7.2 Hz, 6H)

[0960] 31P NMR (162 MHz, CHLOROFORM-d) 5 = -8.41 (s, IP), -8.41 (s, IP) TLC: Petroleum ether: Ethyl acetate = 1:1, Rf = 0.4

[0961] 3. Preparation of compound 2:

[0962]

[0963] To a solution of compound 1 (30 g, 116.18 mmol) in THF (420 mL) was added imidazole (20.56 g, 302.06 mmol), I2(47.18 g, 185.88 mmol) and PPh3(48.75 g, 185.88 mmol) at 0°C. The mixture was stirred at 25°C for 6 hr. TLC indicated compound 1 was consumed completely and two new spots formed. The reaction was clean according to TLC. The reaction was quenched by 10% aqueous sodium thiosulfate solution (800 ml). After removing the solvent and volatiles under reduced pressure, the residue was extracted into Dichloromethane (200 mL*3) and washed with saturated aqueous NaHCCf solution. The organic layer was separated, dried over anhydrous Na2SO4, filtered and concentrated. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 1:0to 0:1 to di chloromethane: methanol =1:0 to 3:1). The crude product was purified by recrystallization from Ethyl acetate (100 mL), Dichloromethane (300 mL) and Methanol (50 mL) at 15°C. Compound 2 (200 g, 93.55% yield) was obtained as a purple solid.

[0964] 'H NMR (400 MHz, DMSO-d6) 5 = 11.43 (s, 1H), 7.68 (d, J = 8.2 Hz, 1H), 5.87 (d, J = 5.6 Hz, 1H), 5.70-5.68 (m, 1H), 5.46 (d, J = 6.0 Hz, 1H), 4.05-4.01 (m, 1H), 4.00-3.95 (m, 1H), 3.88-3.82 (m, 1H), 3.54-3.53 (m, 1H), 3.42-3.40 (m, 1H), 3.34 (s, 3H) LCMS (M+H+): 369.0

[0965] TLC: Di chloromethane: Methanol = 10:1, Rf = 0.45

[0966] 4. Preparation of compound 3:

[0967]

[0968] To a solution of compound 2 (24 g, 65.20 mmol) in 1, 2-dimethoxyethane (300 mL) and H2O (60 mL) was added NaN3 (3.66 g, 56.30 mmol) at 0°C under N2. The mixture was stirred at 90°C for 12 hr. LCMS showed compound 2 was remained and the desired mass was detected. The reaction was quenched by H2O (500 mL), and extracted with Ethyl acetate (400 mL*3). The combined organic layers were washed with saturated aqueous NaCl 300 mL, dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, petroleum ether: ethyl acetate = 1:0 to 0: 1). The crude product was triturated with Ethyl acetate (50 mL) at 15°C for 10 min. Compound 3 (49 g, 85.51% yield) was obtained as a white solid.

[0969] XH NMR (400 MHz, DMSO-d6) 5 = 11.48 - 10.91 (m, 1H), 7.70 (d, J = 8.2 Hz, 1H), 5.83 (d, J = 4.8 Hz, 1H), 5.68 (d, J = 8.0 Hz, 1H), 5.36 (br d, J = 5.8 Hz, 1H), 4.07 (q, J = 5.2 Hz, 1H), 3.95 - 3.89 (m, 2H), 3.61 (d, J = 4.8 Hz, 2H), 3.36 (s, 3H)

[0970] LCMS: (M+H+): 284.0, purity: 90.16%

[0971] TLC: Di chloromethane: Methanol = 10:1, Rf = 0.45

[0972] 5. Preparation of WV-NU-343:

[0973]

[0974] WV-NU-343 WV-NU-306 1,5-Triazolyl Phosphonate 1,4-Triazolyl phospnahte To a solution of compound 3 (10 g, 35.31 mmol) and compound 3A (11.45 g, 70.61 mmol) in Tol. (100 mL) was added chlororuthenium; cyclopentane; triphenylphosphane (3.61 g, 4.94 mmol). The mixture was stirred at 90°C for 12 hr. LCMS showed compound 3 was remained and the desired mass was detected. The reaction mixture was concentrated under reduced pressure to give a residue. The residue was purified by prep-HPLC (FA condition; column: Phenomenex luna cl8 250mm*100mm*15um; mobile phase: [H2O (0.02%FA)-ACN]; gradient: 5%-25% B over 25.0 min). Compound WV-NU-343 (1.2 g, 1.91% yield) was obtained as ayellow solid. Compound WV-NU-306 (22 g, 34.98% yield) was obtained as a pale yellow solid.

[0975] WV-NU-343:

[0976] 1HNMR(400 MHz, DMSO-d6) 8 = 11.42 (d, J = 1.6 Hz, 1H), 8.21 (s, 1H), 7.68 (d, J = 8.0 Hz, 1H), 5.79 (d, J = 5.0 Hz, 1H), 5.66-5.64 (m, 1H), 5.49 (d, J = 6.0 Hz, 1H), 4.89 (d, J = 6.0 Hz, 2H), 4.31 - 4.22 (m, 2H), 4.13 - 4.03 (m, 4H), 4.02 - 3.97 (m, 1H), 3.37 (s, 3H), 1.23 (q, J = 7.1 Hz, 6H)

[0977] 31P NMR (162 MHz, DMSO-d6) 6 = 3.10 (s, IP)

[0978] LCMS (M+H+): 446.1, purity: 97.53%

[0979] WV-NU-306:

[0980] 1HNMR(400 MHz, DMSO-d6) 5 = 11.41 (d, J = 1.6 Hz, 1H), 8.62 (s, 1H), 7.55 (d, J = 8.2 Hz, 1H), 5.80 (d, J = 4.8 Hz, 1H), 5.65-5.63 (m, 1H), 5.49 (d, J = 6.0 Hz, 1H), 4.87 - 4.69 (m, 2H), 4.21 (td, J = 4.6, 7.8 Hz, 1H), 4.15 (q, J = 5.6 Hz, 1H), 4.12 - 4.03 (m, 4H), 3.93 (t, J = 5.0 Hz, 1H), 3.37 (s, 3H), 1.24 (t, J = 7.0 Hz, 6H)

[0981] 31P NMR (162 MHz, DMSO-d6) 5 = 7.16 (s, IP)

[0982] LCMS (M+H+): 446.1, purity: 94.23%EXAMPLE 13. Synthesis of WV-NU-342

[0983]

[0984] Compound 1 A (30 g, 217.23 mmol) was added to a stirred mixture of pyrrolidine-2-carboxylic acid (37.51 g, 325.85 mmol) in Tol. (150 mL) at 110°C. Benzaldehyde (34.58 g, 325.85 mmol) was then added to the reaction mixture in small portions over 3 h. TLC indicated compound 1A was consumed completely and three new spots formed. Thereaction was clean according to TLC. The resultant solution was portioned to H2O (500 mL), and extracted with EtOAc (2 XI 000 mL). The organic layer was washed with brine (300 mL) and dried over ISfeSC The filtrate was evaporated in vacuo. The residue was purified by column chromatography (SiCh, petroleum ether / ethyl acetate = 100:1 to 1:1). Compound 2A (55 g, 85.15% yield) was obtained as a yellow oil.

[0985] 'H NMR (400 MHz, CHLOROFORM-d, 25°C): 5 = 7.16-7.30 (m, 5H), 5.22 (s, 1H), 4.37 (d, J = 13.0 Hz, 1H), 4.02-4.23 (m, 4H), 3.34 (d, J = 13.0 Hz, 1H), 2.91 (dd, J = 9.8, 5.8 Hz, 1H), 2.86 (ddd, J = 9.0, 6.5, 2.8 Hz, 1H), 2.16 (td, J = 9.4, 6.7 Hz, 1H), 1.97-2.10 (m, 2H), 1.61-1.77 (m, 2H), 1.27 ppm (td, J = 7.0, 4.6 Hz, 6H)

[0986] 31P NMR (162 MHz, CHLOROFORM-d, 25°C): 5 = 27.13 ppm (s, IP)

[0987] TLC: Petroleum ether: Ethyl acetate = 1: 1; Rf = 0.5

[0988] 2. Preparation of compound 3 A:

[0989]

[0990] To a solution of compound 2A (25 g, 84.08 mmol), AcOH (7.57 g, 126.12 mmol) in EtOH (250 mL) was added Pd (OH)2 (2.5 g, 20% purity) under N2 atmosphere. The suspension was degassed and purged with H2 for 3 times. The mixture was stirred under H2 (15 Psi) at 25°C for 12 hr. TLC indicated compound 2A was consumed completely and one new spot formed. The reaction was clean according to TLC. Filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, dichloromethane: methanol = 100:1 to 13:1). Compound 3 A (31 g, 88.97% yield) was obtained as a yellow oil.

[0991] ‘HNMR (400 MHz, CHLOROFORM-d, 25°C): 5 = 4.04-4.16 (m, 4H), 3.33 (td, J = 8.0, 6.3 Hz, 1H), 2.96-3.05 (m, 1H), 2.85-2.96 (m, 1H), 1.97-2.06 (m, 1H), 1.77-1.94 (m, 2H), 1.66-1.76 (m, 1H), 1.27 ppm (t, J = 7.0 Hz, 6H)

[0992] TLC: di chloromethane: methanol = 10:1, Rf = 0.15

[0993] 3. Preparation of compound 2:

[0994]

[0995] 1 2

[0996] To a solution of compound 1 (50 g, 193.63 mmol) in DMF (500 mL) was added imidazole (65.91 g, 968.14 mmol) and TBSC1 (116.73 g, 774.51 mmol). The mixture was stirred at 25°C for 3hr. TLC indicated compound 1 was consumed completely and one new spot formed. The reaction was clean according to TLC. The reaction mixture was partitioned between Ethyl acetate (3L) and H2O (IL). The organic phase was separated, washed with brine (500 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO₂, petroleum ether: ethyl acetate = 100:1 to 0:1). Compound 2 (94 g, 99.74% yield) was obtained as a yellow oil.

[0997] ‘HNMR (400 MHz, CHLOROFORM-d, 25°C): 5 = 8.63 (br s, 1H), 7.96 (d, J = 8.0 Hz, 1H), 5.83 (d, J = 1.6 Hz, 1H), 5.57 (dd, J = 8.0, 2.0 Hz, 1H), 4.13 (dd, J = 7.0, 4.9 Hz, 1H), 3.91-3.97 (m, 2H), 3.63-3.70 (m, 1H), 3.50 (dd, J = 4.8, 1.7 Hz, 1H), 3.45 (s, 3H), 0.82 (d, J = 13.0 Hz, 18H), -0.04-0.03 ppm (m, 12H)

[0998] LCMS: (M+H+) = 487.4

[0999] TLC: Petroleum ether: Ethyl acetate = 1:1, Rf = 0.48

[1000] 4. Preparation of compound 3:

[1001]

[1002] For 2 batches: To a solution of compound 2 (60 g, 123.27 mmol) in H2O (300 mL) / TFA (300 mL) / THF (600 mL). The mixture was stirred at 0°C for 3hr. TLC indicated compound 2 was consumed completely and one new spot formed. The reaction was clean according to TLC. 2 reactions were combined for workup. After completion of reaction, the resulting mixture was added con. NFL^EEO (IL) to pH = 7, and then extracted with ethyl acetate (2 L) washed with brine 500 mL dried over Na2SO4, filtered and concentrated underreduced pressure to give a residue. The residue was purified by column chromatography (SiO₂, petroleum ether: ethyl acetate = 100:1 to 0:1). Compound 3 (60 g, 65.34% yield) was obtained as a white solid.

[1003] 'H NMR (400 MHz, CHLOROFORM-d, 25°C): 5 = 9.38 (s, 1H), 7.72 (d, J = 8.0 Hz, 1H), 5.67-5.76 (m, 2H), 4.36 (t, J = 5.4 Hz, 1H), 3.94-4.08 (m, 3H), 3.75 (br d, J = 12.2 Hz, 1H), 3.49 (s, 3H), 2.87 (br s, 1H), 0.92 (s, 9H), 0.11 ppm (d, J = 5.0 Hz, 6H) TLC: petroleum ether: ethyl acetate = 1:2, Rf = 0.28

[1004] 5. Preparation of compound 4:

[1005]

[1006] 3 4

[1007] DMP (22.77 g, 53.69 mmol) was added to a stirred and cooled 0°C solution of compound 3 (20 g, 53.69 mmol) in anhydrous DCM (300 mL) under argon atmosphere. The cooling bath was removed, and the mixture was stirred at 25°C for 3hr. TLC indicated compound 3 was consumed completely and one new spot formed. The reaction was clean according to TLC. The mixture was cooled to 0°C and poured to a vigorously stirred mixture of 10% solution of sodium thiosulfate (100 mL) and saturated solution of sodium bicarbonate (100 mL). After stirring at room temperature for 45 minutes significant precipitation occurred. The precipitate was filtered off and the solids where washed with DCM (200 mL x 2). The filtrate was placed in a separator funnel, the organic phase was separated and dried over anhydrous sodium sulfate. Without further purification. Compound 4 (19 g, crude) was obtained as a white solid.

[1008] TLC: (Petroleum ether: Ethyl acetate = 0:1), Rf = 0.58

[1009] 6. Preparation of compound 5:

[1010]

[1011] 4 5

[1012] To a solution of compound 3A (15.94 g, 76.93 mmol) compound 4 (19 g, 51.29 mmol) in MeOH (200 mL) was added NaBH (OAc)s (43.48 g, 205.14 mmol). The mixture was stirred at 15°C for 12 hr. TLC indicated compound 4 was consumed completely and two new spots formed. The reaction was clean according to TLC. Concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 100:1 to 0;l). Compound 5 (13 g, 45.13% yield) was obtained as a white solid.

[1013] 1H NMR (400 MHz, DMSO-d6, 28°C): 5 = 11.36 (dd, J = 8.4, 1.7 Hz, 1H), 7.59-7.85 (m, 1H), 5.81 (dd, J = 17.6, 5.1 Hz, 1H), 5.57-5.72 (m, 1H), 4.31 (t, J = 4.2 Hz, 1H), 3.97-4.16 (m, 4H), 3.78-3.96 (m, 2H), 3.30-3.35 (m, 3H), 3.17-3.27 (m, 1H), 3.01-3.11 (m, 1H), 2.89 (ddd, J = 14.6, 9.8, 5.3 Hz, 1H), 2.53-2.70 (m, 1H), 2.20-2.38 (m, 1H), 1.92-2.08 (m, 1H), 1.79-1.84 (m 1H), 1.61-1.78 (m, 2H), 1.15-1.28 (m, 6H), 0.88 (d, J = 2.3 Hz, 9H), 0.09 ppm (s, 6H)

[1014] TLC: petroleum ether: ethyl acetate = 0:1, Rfi = 0.18; Rf2 = 0.10

[1015] 7. Preparation of compound WV-NU-342:

[1016]

[1017] 2'-OMe-5,-(2-PO(OEt)2-pyrrolidinyl) phosphonate Uridine (WV-NU-342) To a solution of compound 5 (11.5 g, 20.47 mmol) in THF (130 mL) was added TBAF (1 M, 24.57 mL). The mixture was stirred at 25°C for 0.5 hr. TLC indicated compound 5 was consumed completely and one new spot formed. The reaction was clean according to TLC. Concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, di chloromethane: methanol = 100 / 1 to 10 / 1).Compound WV-NU-342 (7.5 g, 77.63% yield, 94.82% purity) was obtained as a yellow solid.

[1018] 1H NMR (400 MHz, DMSO-d6, 25°C): 5 = 11.34 (br d, J = 3.9 Hz, 1H), 7.58-7.83 (m, 1H), 5.76-5.82 (m, 1H), 5.55-5.67 (m, 1H), 5.17 (dd, J = 10.8, 6.1 Hz, 1H), 3.94-4.08

[1019]

[1020]

[1021] WV-NU-345

[1022] Experimental Procedure:

[1023] 1. Preparation of compound 2A:

[1024]

[1025] To a solution of compound 1A (20 g, 203.63 mmol) in THF (285 mL) was added n- BuLi (2.5 M, 81.45 mL) dropwise at -78°C and the reaction was allowed to warm up to -20 °C during 2 h before it was re-cooled to -78°C. Then S (6.60 g, 205.71 mmol) was added in portions and the solution was warmed to 0°C and treated with BnBr (35.18 g, 205.66 mmol, 24.43 mL), which was stirred at 25°C for 12 hr. TLC indicated compound 1A was consumed completely and one new spot formed. The reaction was clean according to TLC. 2 reactions were combined for workup. The reaction was quenched with saturated aqueous NH4CI (1000 mL). The aqueous layer was extracted with Petroleum ether (2000 mL) and the combined organic layer was washed sequentially with water (500 mL) and brine (500 mL), dried over anhydrous Na2SC>4. The residue was purified by column chromatography (SiCh, petroleum ether: ethyl acetate = 100: 0 to 40: 1). Compound 2A (80 g, 89.12% yield) was obtained as a yellow oil.

[1026] H NMR (400 MHz, CHLOROFORM-d, 25°C): δ = 7.12-7.25 (m, 5H), 3.80 (s, 2H), -0.02 (s, 9H)

[1027] TLC: petroleum ether: ethyl acetate = 0:1, Rf = 0.67

[1028] 2. Prep2. Preparation of compound 3A:BnS^

[1029]

[1030] 2A 3A

[1031] To a solution of compound 2A (40 g, 181.48 mmol) in THF (800 mL) was added TBAF (1 M, 217.72 mL). The mixture was stirred at 25°C for 12 hr. TLC indicated compound 2A was consumed completely and one new spot formed. The reaction was clean according to TLC. Two reactions were combined for workup. The reaction mixture was partitioned between H2O (1000 mL) and Ethyl acetate (1000 mL). The organic phase was separated, washed with brine (300 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, petroleum ether: ethyl acetate = 100:1 to 10:1). Compound 3 A (50 g, 92.94% yield) was obtained as a yellow oil.

[1032] 'H NMR (400 MHz, CHLOROFORM-d, 25°C): 5 = 7.21-7.31 (m, 5H), 3.89 (s, 2H), 2.74 ppm (s, 1H)

[1033] TLC: petroleum ether: ethyl acetate = 1:0, Rf = 0.52

[1034] 3. Preparation of compound 2:

[1035]

[1036] 1 2

[1037] To a solution of compound 1 (50 g, 193.63 mmol) in THF (700 mL) was added IMIDAZOLE (34.27 g, 503.43 mmol), I2(78.63 g, 309.80 mmol) and PPh3(81.26 g, 309.80 mmol) at 0°C. The mixture was stirred at 25°C for 12 hr. TLC indicated compound 1 was consumed completely and one new spot formed. The reaction was clean according to TLC. Two reactions were combined for workup. The reaction was quenched by 10% aqueous sodium thiosulfate solution (500 mL). After removing the solvent and volatiles under reduced pressure, the residue was extracted into EtOAc (1000 mL*3) and washed with saturated aqueous NaHCO3 solution (500 mL). The organic layer was separated, dried over anhydrous Na₂SO₄U, filtered and concentrated. The residue was purified by column chromatography (SiCh, dichloromethane: methanol = 100:1 to 10:1). Compound 2(140 g, 98.59% yield) was obtained as a white solid.iHNMR (400 MHz, DMSO-d6, 25°C): 5 = 11.42 (s, 1H), 7.68 (d, J = 8.0 Hz, 1H), 5.86 (d, J = 5.4 Hz, 1H), 5.69 (d, J = 8.0 Hz, 1H), 5.45 (d, J = 6.0 Hz, 1H), 3.95-4.00 (m, 1H), 3.82-3.88 (m, 1H), 3.55 (dd, J= 10.6, 5.4 Hz, 1H), 3.40 (dd, J= 10.6, 6.9 Hz, 1H), 3.34 ppm (s, 3H)

[1038] TLC: (Dichloromethane: Methanol = 10:1), Rf = 0.48

[1039] 4. Preparation of compound 3:

[1040]

[1041] To a solution of compound 2 (25 g, 67.91 mmol) in 1, 2-dimethoxyethane (500 mL) and H2O (70 mL) was added NaNs (4.27 g, 65.64 mmol) at 0°C under N2. The mixture was stirred at 90°C for 12hr. LCMS showed compound 2 was remained and the desired mass was detected. The reaction was quenched by H2O (1000 mL) and extracted with Ethyl acetate (1500 mL*3). The combined organic layers were washed with saturated aqueous NaCl (500 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, dichloromethane: methanol = 100: 1 to 0: 1). Compound 3 (65 g, 87.25% yield) was obtained as a white solid.

[1042] ‘HNMR (400 MHz, DMSO-d6, 25°C): 5 = 11.40 (s, 1H), 7.63-7.77 (m, 1H), 5.83 (d, J = 4.9 Hz, 1H), 5.68 (d, J = 8.1 Hz, 1H), 5.35 (d, J = 6.3 Hz, 1H), 4.05-4.12 (m, 1H), 3.88-3.96 (m, 2H), 3.61 (d, J = 4.9 Hz, 2H), 3.36 ppm (s, 3H)

[1043] LCMS: (M+H +) = 284

[1044] TLC: di chloromethane: methanol = 10:1, Rf = 0.45

[1045] 5. Preparation of compound 4:

[1046]

[1047] To a solution of compound 3A (15.39 g, 103.80 mmol) and compound 3 (24.5 g, 86.50 mmol) in DMF (115 mL) and THF (230 mL) was degassed and purged with N2 for 3 times, then DIEA (22.36 g, 173.00 mmol), Cui (32.95 g, 173.00 mmol) was added. The mixture was stirred at 25°C for 12 hr under N2 atmosphere. LCMS showed compound 3 was consumed completely and the desired mass was detected. The reaction mixture was concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO₂, petroleum ether: ethyl acetate = 100:0 to 0:1). Compound 4 (74.64 g, crude) was obtained as a yellow solid.

[1048] LCMS: (M+H+) = 432.1

[1049] TLC: petroleum ether: ethyl acetate = 1:3, Rf = 0.42

[1050] 6. Preparation of compound 5:

[1051]

[1052] 4 5

[1053] To a solution of compound 4 (74 g, 171.51 mmol) in Py (700 mL) was added AC2O (26.26 g, 257.26 mmol). The mixture was stirred at 15°C for 12hr. TLC indicated compound 4 was consumed completely and one new spot formed. The reaction was clean according to TLC. Concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, petroleum ether / ethyl acetate = 100:1 to 0:1). Compound 5 (50 g, 61.57% yield) was obtained as a white solid.

[1054] 1HNMR (400 MHz, DMSO-d6, 25°C): 5 = 11.44-11.61 (m, 1H), 8.04 (s, 1H), 7.70 (d, J = 8.0 Hz, 1H), 7.13-7.32 (m, 5H), 5.81 (d, J = 5.7 Hz, 1H), 5.71 (dd, J = 8.0, 2.0 Hz, 1H), 5.23-5.31 (m, 1H), 4.65-4.79 (m, 2H), 4.34-4.44 (m, 1H), 4.28 (t, J = 5.7 Hz, 1H), 4.11 (s, 2H), 3.29 (s, 3H), 2.09 ppm (s, 3H)

[1055] LCMS: (M+H+) = 474.4

[1056] TLC: petroleum ether: ethyl acetate = 1:1, Rf = 0.42

[1057] 7. Preparation of compound 6:

[1058]

[1059] NCS (30.46 g, 228.09 mmol) was added to a solution of compound 5 (40 g, 84.48 mmol) in AcOH (400 mL) and Water (200 mL) and the mixture stirred at 15°C for Ihr. TLC indicated compound 5 was consumed completely and one new spot formed. The reaction was clean according to TLC. Water (500 mL) was added and the mixture was extracted with ethyl acetate (1000 mL). The organic phase was washed sequentially with a saturated aqueous sodium hydrogen carbonate solution (3 * 300 mL) and brine (400 mL), then dried (MgSCU), concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, petroleum ether / ethyl acetate = 100:1 to 0: 1). Compound 6 (30 g, 78.95% yield) was obtained as a white solid.

[1060] 'H NMR (400 MHz, DMSO-d6, 27°C): 5 = 11.50 (br s, 1H), 8.16 (d, J = 3.1 Hz, 1H), 7.65 (dd, J = 8.0, 4.5 Hz, 1H), 5.87 (d, J = 5.8 Hz, 1H), 5.77 (dd, J = 8.0, 2.0 Hz, 1H), 5.29-5.38 (m, 1H), 4.83 (br d, J = 6.0 Hz, 2H), 4.45-4.54 (m, 1H), 4.26 (td, J = 5.7, 2.5 Hz, 1H), 3.34 (d, J = 2.0 Hz, 3H), 2.14 ppm (d, J = 2.0 Hz, 3H)

[1061] LCMS: (M+H+) = 450.2

[1062] TLC: petroleum ether: ethyl acetate = 0:1, Rf = 0.72

[1063] 8. Preparation of compound WV-NU-345:

[1064]

[1065] 6 WV-NU-345

[1066] 2'-OMe-5'-Sufonylamindo Triazolyl Uridine (WV-NU-345) A mixture of compound 6 (10 g, 22.23 mmol) in MeNH2 (2 M, THF 100 mL) was degassed and purged with N2 for 3 times, and then the mixture was stirred at 15°C for 12hr under N2 atmosphere. LCMS showed compound 6 was consumed completely and one main peak with desired m / z. Concentrated under reduced pressure to give a residue. The residuewas purified by column chromatography (SiCh, dichloromethane: methanol= 100:1 to 0:1). Compound WV-NU-345 (7 g, 16.60 mmol, 74.65% yield, 95.56% purity) was obtained as a white solid.

[1067] ‘HNMR (400 MHz, DMSO-d6, 27°C): 5 = 8.69 (s, 1H), 7.66-7.91 (m, 1H), 7.58 (d, J = 8.0 Hz, 1H), 5.81 (d, J = 4.8 Hz, 1H), 5.66 (d, J = 8.0 Hz, 1H), 5.51 (br d, J = 5.8 Hz, 1H), 4.79-4.88 (m, 1H), 4.70-4.78 (m, 1H), 4.20-4.27 (m, 1H), 4.16 (q, J = 5.0 Hz, 1H), 3.95 (t, J = 5.0 Hz, 1H), 3.37-3.39 (m, 3H), 3.18 (d, J = 3.1 Hz, 1H), 2.54 ppm (s, 3H) LCMS: (M+H+) = 403, purity: 95.56%

[1068] TLC: di chloromethane: methanol = 10:1, Rf = 0.28

[1069] EXAMPLE 15. Synthesis of WV-NU-365

[1070]

[1071] WV-NU-365

[1072] 2'-OMe-5'-PO(OEt)2-Aziridinyl Phosphonate Uridine (WV-NU-365) diethyl (1-(((2R,3R,4R,5R)-5-(2,4-dioxo-3,4-dihydropyrimidin-1(2 / - / )-yl)-3-hydroxy-4- methoxytetrahydrofuran-2-yl)methyl)aziridin-2-yl)phosphonate (WV-NU-365)

[1073] General Scheme:

[1074]

[1075] Experimental Procedures:

[1076] / . Preparation of compound 2 A:

[1077]

[1078] Compound 1A (20 g, 121.85 mmol) was added into a pre-dried three necked flask and was dissolved in DCM (200 mL) and the reaction mixture cooled to 0°C, Br2 (27.26 g, 170.59 mmol) was added to this solution, after 25°C stirring at 0.5 hr. TLC indicated compound 1 A was consumed completely and one new spot formed. The reaction was clean according to TLC. The reaction mixture concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, petroleum ether: ethyl acetate = 100: 1 to 1: 1). Compound 2A (30 g, 76.00% yield) was obtained as a yellow oil.

[1079] 'H NMR (400 MHz, CHLOROFORM-d, 25°C): 5 = 4.27 (quind, J = 7.3, 4.4 Hz, 4H), 4.00-4.11 (m, 2H), 3.60-3.72 (m, 1H), 1.39 ppm (t, J = 7.1 Hz, 6H)

[1080] TLC: petroleum ether: ethyl acetate = 1: 1, Rf = 0.5

[1081] 2. Preparation of compound 4:

[1082]

[1083] 3 4

[1084] To a solution of compound 3 (15 g, 52.96 mmol) in MeOH (150 mL) was added Pd / C (1.5 g, 1.41 mmol, 10% purity) under N2 atmosphere. The suspension was degassed and purged with H2 for 3 times. The mixture was stirred under H2 (5 Psi) at 25°C for 12hr. TLC indicated compound 3 was consumed completely and one new spot formed. The reaction was clean according to TLC. Filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, dichloromethane: methanol =100:1 to 20:1). Compound 4 (13 g, 95.43% yield) was obtained as a white solid.

[1085] 1H NMR (400 MHz, DMSO-d6, 25°C): 5 = 7.93 (d, J = 8.0 Hz, 1H), 5.83 (d, J = 5.0 Hz, 1H), 5.61-5.69 (m, 1H), 4.09 (t, J = 4.8 Hz, 1H), 3.85 (br t, J = 5.2 Hz, 1H), 3.78 (q, J = 4.8 Hz, 1H), 3.34-3.37 (m, 3H), 2.75-2.87 ppm (m, 2H)

[1086] LCMS: (M+H+) = 258.0

[1087] TLC: di chloromethane: methanol = 10:1, Rf = 0.2

[1088] 3. Preparation of compound WV-NU-365:

[1089]

[1090] 2'-OMe-5'-PO(OEt)2-Aziridinyl Phosphonate Uridine (WV-NU-365) Compound 2A (22.67 g, 69.97 mmol) was weighed into a pre-dried three necked flask and dissolved by adding MeOH (230 mL). After adding TEA (14.16 g, 139.95 mmol) at 25°C for 0.5 h. Then the compound 4 (12 g, 46.65 mmol) was added and the resulting mixture was refluxed at 70 °C for 12 hr. LCMS showed compound 4 was consumed completely and one main peak with desired m / z. Concentrated under reduced pressure to give a residue. The residue was purified by prep-HPLC (column: Welch X timate Cl 8 250*100mm#10um; mobile phase: [H2O (lOmM NH4HCO3)-ACN]; gradient: 0%-30% B over 18.0 min). Compound WV-NU-365 (14.5 g, 70.55% yield, 95.18 % purity) was obtained as a yellow solid.

[1091] 'H NMR (400 MHz, DMSO-d6, 25°C): 5 = 11.28-11.47 (m, 1H), 7.81-8.21 (m, 1H), 5.85 (t, J = 4.6 Hz, 1H), 5.60 (dd, J = 13.8, 8.0 Hz, 1H), 5.17-5.32 (m, 1H), 4.10-4.22 (m, 1H), 3.97-4.09 (m, 4H), 3.88-3.96 (m, 1H), 3.85 (td, J = 4.8, 1.8 Hz, 1H), 3.38 (d, J = 3.6 Hz, 3H), 2.74-2.97 (m, 1H), 2.19-2.43 (m, 1H), 1.92-2.00 (m, 1H), 1.82-1.91 (m, 1H), 1.67-1.82 (m, 1H), 1.19-1.32 ppm (m, 6H)

[1092] 31P NMR (162 MHz, DMSO-d6, 25°C): 5 = 22.94 ppm (d, J= 77.3 Hz, IP) LCMS: (M+H+) = 420.1, purity: 95.18 %

[1093] EXAMPLE 16. Synthesis of WV-NU-426

[1094]

[1095] WV-NU-426

[1096] General Scheme:

[1097]

[1098] 1 2

[1099] To a solution of compound 1 (50 g, 193.63 mmol) in DMF (1000 mL) was added imidazole (52.73 g, 774.51 mmol) and TBSC1 (87.55 g, 580.88 mmol). The mixture was stirred at 20°C for 12 hr. LCMS showed that compound 1 was consumed completely and the desired mass was detected. The reaction mixture was concentrated under reduced pressure to remove DMF. The residue was diluted with FbO 1500 mL and extracted with EtOAc (500 mL*3). The combined organic layers were washed with brine 1500 mL, dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. Compound 2 (188 g, crude) was obtained as a yellow oil.

[1100] LCMS (M+H+): 487.4, LCMS purity: 99%

[1101] 2. Preparation of compound 3:

[1102]

[1103] To a solution of compound 2 (94 g, 193.12 mmol) in THF (1000 mL) was added TFA (383.75 g, 3.37 mol) and H2O (250.00 g, 13.88 mol). The mixture was stirred at 0°C for 3 hr. TLC indicated compound 2 was consumed completely and one new spot formed. The reaction mixture was quenched with NH3. H2O (230 mL*4) at 0°C. The residue was diluted with H2O 500 mL and extracted with DCM (1000 mL*3). The combined organic layers were washed with brine 1000 mL, dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, petroleum ether: ethyl acetate = 1:0 to 0:1). Compound 3 (45 g, 62.56% yield) was obtained as a white solid.

[1104] 'HNMR (400 MHz, DMSO-d6) 5 = 11.36 (br s, 1H), 7.93 (d, J = 8.0 Hz, 1H), 5.83 (d, J = 4.8 Hz, 1H), 5.66 (d, J = 8.1 Hz, 1H), 5.20 (br t, J = 4.6 Hz, 1H), 4.29 (t, J = 4.6 Hz, 1H), 3.87 - 3.81 (m, 2H), 3.70 - 3.62 (m, 1H), 3.57 - 3.50 (m, 1H), 3.34 (s, 3H), 0.88 (s, 9H), 0.09 (s, 6H)

[1105] LCMS (M+H+): 373.2, LCMS purity: 97%

[1106] TLC: petroleum ether: ethyl acetate = 0:1, Rf = 0.6

[1107] 3. Preparation of compound 4:

[1108]

[1109] To a solution of compound 3 (25 g, 67.12 mmol) in ACN (300 mL) was added IBX (37.59 g, 134.23 mmol) at 0°C. The mixture was stirred at 70°C for 3 hr. TLC indicated compound 3 was consumed completely and one new spot formed. The reaction mixture was filtered and concentrated under reduced pressure to get crude product. The crude product was used into the next step without further purification. Compound 4 (49 g, crude) was obtained as a white solid.1H NMR (400 MHz, DMS0-d6) 5 = 11.44 - 11.24 (m, 2H), 7.82 - 7.78 (m, 1H), 5.85 - 5.81 (m, 1H), 5.67 - 5.61 (m, 1H), 4.36 - 4.31 (m, 1H), 3.89 - 3.85 (m, 1H), 3.77 - 3.73 (m, 1H), 3.21 - 3.17 (m, 3H), 0.82 - 0.79 (m, 9H), 0.00 - -0.02 (m, 6H)

[1110] TLC: commercial hexanes: ethyl acetate = 1:1, Rf = 0.18

[1111]

[1112] To a solution of methyl (triphenyl) phosphonium;bromide (141.74 g, 396.79 mmol) and potassium;2-methylpropan-2-olate (44.52 g, 396.79 mmol) in THF (500 mL) was added compound 4 (49 g, 132.26 mmol) in THF (500 mL). The mixture was stirred at 0-20°C for 12 hr. LCMS showed compound 4 was consumed completely and desired mass was detected. The mixture was diluted with DCM (200 mL) and organic layer was washed with saturated NH4CI solution (200 mL). Organic layer then separated, dried over anhydrous Na2SO4, filtered and the filtrate was evaporated to dryness. The residue was purified by column chromatography (SiO2, commercial hexanes: ethyl acetate = 1:0 to 1: 1). Compound 5 (30 g, 61.55% yield) was obtained as a white solid.

[1113] 'HNMR (400 MHz, DMSO-d6) 5 = 11.40 (s, 1H), 7.64 (d, J = 8.1 Hz, 1H), 5.98 (ddd, J = 7.0, 10.2, 17.2 Hz, 1H), 5.78 (d, J = 3.7 Hz, 1H), 5.66 (dd, J = 1.7, 8.0 Hz, 1H), 5.35 (d, J = 17.0 Hz, 1H), 5.27 (d, J = 10.3 Hz, 1H), 4.20 - 4.12 (m, 2H), 3.91 - 3.87 (m, 1H), 3.36 (s, 3H), 0.87 (s, 9H), 0.07 (d, J = 4.9 Hz, 6H)

[1114] LCMS (M+H+): 369.2

[1115] TLC: petroleum ether: ethyl acetate = 1:1, Rf = 0.4

[1116]

[1117] To a solution of compound 5 (8 g, 21.71 mmol) in THF (80 mL) was added N, N-diethylethanamine; trihydrofluoride (10.50 g, 65.13 mmol). The mixture was stirred at 40°C for 6 hr. TLC indicated compound 5 was consumed completely and one new spot formed. The reaction mixture was concentrated under reduced pressure to remove THF. The residue was purified by column chromatography (SiCL, commercial hexanes: ethyl acetate = 1:0 to 0: 1). Compound 6 (5 g, 90.59% yield) was obtained as a white solid.

[1118] LCMS (M+H+): 255.1, LCMS purity: 94%

[1119] TLC: commercial hexanes: ethyl acetate = 0:1, Rf = 0.2

[1120]

[1121] To a solution of compound 6 (5 g, 19.67 mmol,) and [l,3-bis(2,4,6-trimethylphenyl)imidazolidin-2-ylidene]-dichloro-[(2-isopropoxyphenyl)methylene] ruthenium (2.46 g, 3.93 mmol) in DCM (200 mL) was added 4,4,5,5-tetramethyl-2-vinyl-1,3,2-dioxaborolane (6.06 g, 39.33 mmol) under N2. The mixture was stirred at 39 °C for 12 hr. LCMS showed 16% of Reactant 1 remained. Several new peaks were shown on LCMS and 17% of desired compound was detected. The reaction mixture was concentrated under reduced pressure to remove DCM. The residue was purified by column chromatography (SiO2, Commercial hexanes: Ethyl acetate = 1:0 to 0: 1). The crude product was purified by normal-phase HPLC column: Welch Ultimate XB-CN 250*50* lOum; mobile phase: [Heptane-DCM: CAN = 2:1]; gradient: 0%-46% B over 20.0 min. WV-NU-426 (0.7 g, 58.33% yield) was obtained as a white solid.

[1122] 'HNMR (400 MHz, DMSO-d6) 5 = 11.37 (br s, 1H), 7.62 (d, J = 8.1 Hz, 1H), 6.58 (dd, J = 6.3, 18.0 Hz, 1H), 5.81 (d, J = 4.0 Hz, 1H), 5.66 (d, J = 8.0 Hz, 1H), 5.61 (dd, J= 1.1, 18.0 Hz, 1H), 5.36 (d, J = 6.8 Hz, 1H), 4.23 (dt, J= 1.0, 6.2 Hz, 1H), 4.01 (q, J = 6.3 Hz, 1H), 3.89 - 3.83 (m, 1H), 3.38 (s, 3H), 1.21 (s, 12H)

[1123] LCMS (M+H+): 381.1, LCMS purity: 90%

[1124] TLC: commercial hexanes: ethyl acetate = 0:1, Rf = 0.3EXAMPLE 17. Synthesis of WV-NU-344

[1125]

[1126] Experimental Procedure:

[1127] 1. Preparation of compound 2A:

[1128]

[1129] 1A 2A

[1130] To a solution of compound 1A (20 g, 203.63 mmol) in THF (285 mL) was added n- BuLi (2.5 M, 81.45 mL) dropwise at -78°C and the reaction was allowed to warm up to -20 °C during 2 h before it was re-cooled to -78°C. Then S (6.60 g, 205.71 mmol) was added in portions and the solution was warmed to 0°C and treated with BnBr (35.18 g, 205.66 mmol, 24.43 mL), which was stirred at 25 °C for 12 h. TLC indicated compound 1A was consumed completely and one new spot formed. The reaction was clean according to TLC. Two reactions were combined for workup. The reaction was quenched with saturated aqueous NH4CI (1000 mL). The aqueous layer was extracted with petroleum ether (2000mL) and the combined organic layer was washed sequentially with water (500 mL) and brine (500 mL), dried over anhydrous Na₂SO₄ The residue was purified by column chromatography (SiO₂, petroleum ether: ethyl acetate = 100: 0 to 40: 1). Compound 2A (40 g, 89.12% yield) was obtained as a yellow oil.

[1131] 1HNMR(400MHz, CHLOROFORM-d, 25°C): 5 = 7.12-7.25 (m, 5H), 3.80 (s, 2H), -0.02 (S, 9H)

[1132] TLC: petroleum ether: ethyl acetate = 0: 1, Rf = 0.67

[1133] 2. Prep2. Preparation of compound 3A:

[1134] BnS^

[1135]

[1136] 2A 3A

[1137] To a solution of compound 2A (40 g, 181.48 mmol) in THF (800 mL) was added TBAF (1 M, 217.72 mL). The mixture was stirred at 25°C for 12 h. TLC indicated compound 2A was consumed completely and one new spot formed. The reaction was clean according to TLC. Two reactions were combined for workup. The reaction mixture was partitioned between H2O (1000 mL) and Ethyl acetate (1000 mL). The organic phase was separated, washed with brine (300 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO₂, petroleum ether: ethyl acetate = 100: 1 to 10: 1). Compound 3A (25 g, 92.94% yield) was obtained as a yellow oil.

[1138] ‘HNMR (400 MHz, CHLOROFORM-d, 25°C) 5 = 7.21-7.31 (m, 5H), 3.89 (s, 2H), 2.74 ppm (s, 1H)

[1139] TLC: petroleum ether: ethyl acetate = 1: 0, Rf = 0.52

[1140] 3. Preparation of compound 4:

[1141]

[1142] To a solution of compound 3A (15.39 g, 103.80 mmol) and compound 3 (24.5 g, 86.50 mmol) in DMF (115 mL) and THF (230 mL) was degassed and purged with N2 for 3times, then DIEA (22.36 g, 173.00 mmol), Cui (32.95 g, 173.00 mmol) was added. The mixture was stirred at 25°C for 12 h under N2 atmosphere. LCMS showed compound 3 was consumed completely and the desired mass was detected. The reaction mixture was concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO₂, petroleum ether: ethyl acetate = 100:0 to 0:1). Compound 4 (37.64 g, crude) was obtained as a yellow solid.

[1143] LCMS: (M+H+) = 432.1

[1144] TLC: petroleum ether: ethyl acetate = 1: 3, Rf = 0.42

[1145] 4. Preparation of compound 5:

[1146]

[1147] 4 5

[1148] To a solution of compound 4 (74 g, 171.51 mmol) in Py (700 mL) was added AC2O (26.26 g, 257.26 mmol). The mixture was stirred at 15°C for 12 h. TLC indicated compound 4 was consumed completely and one new spot formed. The reaction was clean according to TLC. Concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO₂, petroleum ether: ethyl acetate = 100:1 to 0:1). Compound 5 (50 g, 61.57% yield) was obtained as a white solid.

[1149] 'HNMR (400 MHz, DMSO-d6, 25°C) 5 = 11.44-11.61 (m, 1H), 8.04 (s, 1H), 7.70 (d, J = 8.1 Hz, 1H), 7.13-7.32 (m, 5H), 5.81 (d, J = 5.7 Hz, 1H), 5.71 (dd, J = 8.0, 2.0 Hz, 1H), 5.23-5.31 (m, 1H), 4.65-4.79 (m, 2H), 4.34-4.44 (m, 1H), 4.28 (t, J = 5.7 Hz, 1H), 4.11 (s, 2H), 3.29 (s, 3H), 2.09 ppm (s, 3H)

[1150] LCMS: (M+H+) = 474.4

[1151] TLC: petroleum ether: ethyl acetate = 1: 1, Rf = 0.42

[1152] 5. Preparation of compound 6:

[1153]

[1154] 5 6

[1155] NCS (30.46 g, 228.09 mmol) was added to a solution of compound 5 (40 g, 84.48 mmol) in AcOH (400 mL) and Water (200 mL) and the mixture stirred at 15°C for 1 h. TLC indicated compound 5 was consumed completely and one new spot formed. The reaction was clean according to TLC. Water (500 mL) was added and the mixture was extracted with ethyl acetate (1000 mL). The organic phase was washed sequentially with a saturated aqueous sodium hydrogen carbonate solution (300 mL*3) and brine (400 mL), then dried (MgSCU), concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO₂, petroleum ether: ethyl acetate = 100:1 to 0:1). Compound 6 (30 g, 78.95% yield) was obtained as a white solid.

[1156] 'HNMR (400 MHz, DMSO-d6, 27°C) 5 = 11.50 (br s, 1H), 8.16 (d, J = 3.1 Hz, 1H), 7.65 (dd, J = 8.0, 4.5 Hz, 1H), 5.87 (d, J = 5.8 Hz, 1H), 5.77 (dd, J = 8.0, 2.0 Hz, 1H), 5.29-5.38 (m, 1H), 4.83 (br d, J = 6.0 Hz, 2H), 4.45-4.54 (m, 1H), 4.26 (td, J = 5.7, 2.5 Hz, 1H), 3.34 (d, J = 2.0 Hz, 3H), 2.14 ppm (d, J = 2.0 Hz, 3H)

[1157] LCMS: (M+H+) = 450.2

[1158] TLC: (petroleum ether: ethyl acetate = 0: 1), Rf = 0.72

[1159] 6. Preparation of compound 7:

[1160]

[1161] To a solution of compound 6 (17 g, 37.79 mmol) in isobutanol (70 mL) was added DIEA (9.77 g, 75.59 mmol, 13.17 mL). The mixture was stirred at 60°C for 12 h. LCMS showed compound 6 was consumed completely and desired mass was detected. The mixture was concentrated. The residue was purified by column chromatography (SiO₂, petroleum ether: ethyl acetate = 1:0 to 0: 1). Compound 7 (3 g, 16.28% yield) was obtained as a yellowoil.

[1162] 1HNMR(400MHz, DMSO-d6) 5 = 11.48 (s, 1H), 9.04 (s, 1H), 7.80 - 7.71 (m, 1H), 5.80 (d, J = 5.8 Hz, 1H), 5.70 (dd, J = 1.8, 8.0 Hz, 1H), 5.28 (t, J = 4.9 Hz, 1H), 4.95 - 4.80 (m, 2H), 4.53 - 4.46 (m, 1H), 4.42 - 4.30 (m, 1H), 3.98 (d, J = 6.4 Hz, 2H), 3.28 (s, 3H), 2.08 (s, 3H), 1.88 (quind, J = 6.5, 13.1 Hz, 1H), 0.87 - 0.79 (m, 6H)

[1163] LCMS: (M+H+) = 488.1

[1164] TLC: petroleum ether: ethyl acetate = 0: 1, Rf = 0.31

[1165] 7. Preparation of compound WV-NU-344:

[1166]

[1167] To a solution of compound 7 (3 g, 6.15 mmol) in MeOH (4 mL) H2O (1 mL) was added TEA (9 mL). The mixture was stirred at 25 °C for 12 h. LCMS showed compound 7 was consumed completely and desired mass was detected. The mixture was concentrated. The residue was purified by prep-HPLC (column: Waters Xbridge BEH C18 250 * 50mm * lOum; mobile phase: [H2O (10mMNH4HCO3)-ACN]; gradient: 10-50% B over 10.0 min). Compound WV-NU-344 (0.37 g, 12.17% yield) was obtained as a white solid.

[1168] 1H NMR (400 MHz, DMSO-d6) 5 = 11.40 (s, 1H), 9.00 (s, 1H), 7.62 (d, J = 8.1 Hz, 1H), 5.80 (d, J = 4.9 Hz, 1H), 5.70 - 5.61 (m, 1H), 5.50 (d, J = 6.1 Hz, 1H), 4.90 - 4.74 (m, 2H), 4.27 - 4.14 (m, 2H), 4.01 - 3.95 (m, 3H), 3.38 (s, 3H), 1.90 (quind, J = 6.6, 13.2 Hz, 1H), 0.84 (d, J = 6.6 Hz, 6H)

[1169] LCMS: (M+H+) = 446.1, purity: 90.17%

[1170] EXAMPLE 18. Synthesis of WV-NU-371

[1171]

[1172] WV-NU-371

[1173] General Scheme:

[1174]

[1175] To a solution of compound 3 (20 g, 70.61 mmol) in DMF (200 mL) was added dropwise SEM-CI (35.32 g, 211.83 mmol, 37.49 mL) at 0°C for 1 h. Then NaH (7.06 g, 176.53 mmol, 60% purity) was added dropwise at 0 °C. The resulting mixture was stirred at 25°C for 10 h. TLC indicated compound 3 was consumed completely and new spot formed. The reaction mixture was quenched by aq. NH4CI (50 ml) at 0 °C and then the mixture was extracted with EtOAc (50 mL*3), the combined organic layers were washed with aq. NaCl (50 mL*3), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO₂, petroleum ether: ethyl acetate = 1:0 to 1: 1). Compound 4 (30 g, 78.13% yield) was obtained as a yellow oil.'H NMR (400 MHz, DMSO-d6) 5 = 7.83 (d, J = 8.1 Hz, 1H), 5.91 - 5.86 (m, 2H), 5.25 (s, 2H), 4.78 - 4.72 (m, 2H), 4.21 - 4.10 (m, 3H), 3.72 - 3.60 (m, 6H), 3.43 - 3.40 (m, 3H), 0.96 - 0.85 (m, 4H), 0.06 - 0.04 (m, 9H), 0.01 - -0.01 (m, 9H)

[1176] TLC: petroleum ether: ethyl acetate = 0: 1, Rf = 0.86

[1177] 2. Preparation of compound 5:

[1178]

[1179] To a solution of compound 4 (30 g, 55.17 mmol) prop-2 -yn- 1 -ol (6.45 g, 115.05 mmol, 6.80 mL) in t-BuOH (150 mL) and H2O (150 mL) was added CUSO4.5H2O (13.78 g, 55.17 mmol) and sodium ascorbate (10.93 g, 55.17 mmol). The mixture was stirred at 25°C for 12 h. TLC indicated compound 4 was consumed completely and new spot formed. The reaction mixture was extracted with EtOAc (200 mL*3) and H2O 200 mL, then the combined organic layers were dried over Na2SO4, filtered and concentrated. The residue was purified by column chromatography (SiO₂, petroleum ether: ethyl acetate = 1:0 to 0: 1). Compound 5 (18 g, 54.39% yield) was obtained as a yellow oil.

[1180] H NMR (400 MHz, DMSO-d6) 6 = 8.02 (br s, 1H), 7.73 - 7.68 (m, 1H), 7.68 - 7.63 (m, 1H), 7.49 (br d, J = 7.4 Hz, 1H), 5.91 - 5.70 (m, 2H), 5.19 (br s, 3H), 4.71 (br s, 3H), 4.52 (br s, 2H), 4.32 (br s, 1H), 4.24 - 4.11 (m, 3H), 3.69 - 3.53 (m, 4H), 3.36 (s, 3H), 1.71 - 1.56 (m, 2H), 1.37 (qd, J = 7.4, 14.8 Hz, 2H), 0.90 (s, 4H), 0.86 - 0.81 (m, 2H), -0.02 (d, J = 18.8 Hz, 18H)

[1181] LCMS: (M+H+): 328.2

[1182] TLC: petroleum ether: ethyl acetate = 0: 1, Rf = 0.17

[1183] 3. Preparation of compound 6:

[1184]

[1185] To a solution of compound 5 (18 g, 30.01 mmol) in DCM (400 mL) was added CBr₄ (11.94 g, 36.01 mmol) and PPh₃ (11.81 g, 45.01 mmol) at 0°C. The mixture was stirred at 0°C for 1 h. LCMS showed compound 5 was consumed completely and desired mass was detected. The mixture was concentrated The residue was purified by column chromatography (SiO₂, petroleum ether: ethyl acetate = 3:0 to 0:1). Compound 6 (12 g, 60.34% yield) was obtained as a yellow oil.

[1186] (400 MHz, DMSO-d6) 8 = 7.73 - 7.70 (m, 1H), 7.68 - 7.65 (m, 1H), 7.59 (s, 1H), 5.86 - 5.77 (m, 2H), 5.19 (s, 1H), 4.83 - 4.67 (m, 4H), 4.22 (t, J = 6.5 Hz, 3H), 3.57 (br t, J = 7.9 Hz, 3H), 3.36 (br s, 4H), 1.68 - 1.60 (m, 2H), 1.41 - 1.33 (m, 2H), 0.85 - 0.81 (m, 2H), 0.00 (d, J = 1.5 Hz, 9H), -0.05 (s, 9H)

[1187] LCMS: (M+H+): 662.2

[1188] TLC: petroleum ether: ethyl acetate = 0: 1, Rf = 0.75

[1189] 4. Preparation of compound 7:

[1190]

[1191] To a solution of compound 6 (12 g, 18.11 mmol) in ACN (120 mL) was added triethyl phosphite (15.82 g, 95.21 mmol, 16.33 mL). The mixture was stirred at 80°C for 2 h. LCMS showed compound 6 was consumed completely and desired mass was detected. The mixture was concentrated. The residue was purified by column chromatography (SiO₂, petroleum ether: ethyl acetate = 1:0 to 0: 1). Compound 7 (6 g, 46.03% yield) was obtained as a yellow oil.

[1192] H NMR (400 MHz, DMSO-d6) 8 = 7.92 (d, J = 2.3 Hz, 1H), 7.58 (d, J = 8.1 Hz, 1H), 5.87 - 5.78 (m, 2H), 5.18 (s, 2H), 4.78 - 4.67 (m, 4H), 4.35 - 4.26 (m, 1H), 4.16 (t, J = 5.5 Hz, 1H), 4.00 - 3.93 (m, 4H), 3.68 - 3.54 (m, 4H), 3.36 (s, 4H), 3.32 (s, 1H), 3.28 (s, 1H), 1.19 - 1.15 (m, 6H), 0.90 - 0.88 (m, 2H), 0.86 - 0.80 (m, 2H), 0.00 (s, 9H), -0.03 - -0.07 (m, 9H)

[1193] 31P NMR (162 MHz, DMSO-d6) 8 = 25.03 (s, IP)

[1194] LCMS: (M+H+): 720.4TLC: petroleum ether: ethyl acetate = 1:1, Rf = 0.16

[1195] 5. Preparation of compound WV-NU-371:

[1196]

[1197] To a solution of compound 7 (6 g, 8.33 mmol) in DCM (60 mL) was added TFA (9.50 g, 83.34 mmol, 6.19 mL). The mixture was stirred at 25°C for 2 h. LCMS showed compound 7 was consumed completely and desired mass was detected. The mixture was concentrated. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 1:0 to 1:1). Compound WV-NU-371 (2.9 g, 71.93% yield, 94.96% purity) was obtained as a yellow oil.

[1198] 1H NMR (400 MHz, DMSO-d6) 5 = 11.46 - 11.38 (m, 1H), 7.88 (d, J = 2.3 Hz, 1H), 7.56 (d, J = 8.1 Hz, 1H), 5.80 (d, J = 5.3 Hz, 1H), 5.68 - 5.65 (m, 1H), 5.50 (d, J = 5.8 Hz, 1H), 4.78 - 4.60 (m, 2H), 4.16 - 4.09 (m, 2H), 4.03 - 3.92 (m, 4H), 3.82 (t, J = 5.0 Hz, 1H), 3.34 (s, 3H), 3.33 - 3.27 (m, 2H), 1.19 - 1.15 (m, 6H)

[1199] 31P NMR (162 MHz, DMSO-d6) 5 = 25.08 (s, IP)

[1200] LCMS: (M+H+): 460.1, purity: 94.97%

[1201] TLC: di chloromethane: methanol = 10:1, Rf = 0.26

[1202] EXAMPLE 19. Synthesis of WV-NU-395

[1203]

[1204] WV-NU-395

[1205] General Scheme:1 -B Li (1 ) THF

[1206]

[1207]

[1208] 1B

[1209]

[1210] To a solution of compound IB (30 g, 352.33 mmol) in THF (500 mL) was added dropwise n-BuLi (2.5 M, 140.93 mL) at -78°C under N2. After addition, the mixture was stirred at this temperature for 10 min, and then 2,2,2-trifluoro-l-phenyl-ethanone (73.62 g, 422.80 mmol) was added dropwise at -78 °C, the mixture was stirred at this temperature for 10 min, 1-ethoxyphosphonoyloxy ethane (72.99 g, 528.50 mmol) was added dropwise at - 78°C. The resulting mixture was stirred at 25°C for 12h. TLC indicated no of compound IB was remained, and one major new spot with larger polarity was detected. The each reaction mixture was added dropwise NH4CI 250 mL at 0°C, and then diluted with water 1500 mL and extracted with EtOAc (400 mL*3). The combined organic layers were dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by flash silica gel chromatography (ISCO®; 330 g SepaFlash® Silica Flash Column, Eluent of 0-10% Dichloromethane: Methanol @ 150 mL / min). (Plate 1, dichloromethane: methanol = 10:1, Rf = 0.23). Compound 3 A (7.3 g, 9.34% yield, 95% purity) was obtained as a yellow oil.1H NMR (400 MHz, CHLOROFORM-d) 5 = 4.12 - 4.05 (m, 5H), 3.13 - 2.99 (m, 1H), 2.93 (br s, 1H), 2.59 - 2.45 (m, 1H), 1.96 - 1.96 (m, 1H), 1.98 (s, 1H), 2.01 - 1.94 (m, 1H), 1.87 - 1.70 (m, 4H), 1.58 - 1.37 (m, 3H), 1.29 - 1.25 (m, 6H)

[1211] TLC: di chloromethane: methanol = 10:1, Rf = 0.23

[1212] 2. Preparation of compound 2:

[1213]

[1214] 1 2

[1215] To a solution of compound 1 (100 g, 387.26 mmol) in DMF (1000 mL) was added IMIDAZOLE (131.82 g, 1.94 mol) then added TBSCI (233.47 g, 1.55 mol) the reaction mixture was stirred at 25°C for 2h. LCMS showed that compound 2 was consumed completely and the desired mass was detected. The reaction mixture was partitioned between Ethyl acetate (3L) and H2O (IL). The organic phase was separated, washed with brine (500 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. Compound 2 (188 g, crude) was obtained as a white solid.

[1216] LCMS (M+H+): 487.2

[1217]

[1218] To a solution of compound 2 (188 g, 386.24 mmol) in THF (1200 mL) was added H2O (399 mL) and TFA (399 mL), the mixture was stirred at 0°C for 4 h. TLC showed the product was detected. The reaction mixture was added NaHCCL IL then extracted with EtOAc 3000 mL (1000mL*3), the combined organic layers were washed with H2O 3000 mL (1000 mL*3), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 10:1 to 0:1). Compound 3 (79 g, 54.91% yield) was obtained as awhite solid.

[1219] 'H NMR (400 MHz, CHLOROFORM-d) 5 = 9.56 (br s, 1H), 7.74 (d, J = 8.1 Hz, 1H), 5.79 - 5.68 (m, 2H), 4.35 (t, J = 5.3 Hz, 1H), 4.09 - 4.03 (m, 1H), 4.02 - 3.92 (m, 2H), 3.75 (dd, J = 2.0, 12.3 Hz, 1H), 3.49 (s, 3H), 0.91 (s, 9H), 0.11 (d, J = 5.0 Hz, 6H) TLC: petroleum ether: ethyl acetate = 1:1, Rf = 0.38

[1220]

[1221] A mixture of compound 3 (12.5 g, 33.56 mmol), IBX (18.79 g, 67.12 mmol) in ACN (100 mL) was degassed and purged with N2 for 3 times, and then the mixture was stirred at 50°C for 6 h under N2 atmosphere. LCMS showed compound 3 was consumed completely desired mass was detected. The mixture was filtered to remove the insoluble. The filter liquor was concentrated in vacuum. Compound 4 (13 g, crude) was obtained as a yellow solid.

[1222] 'H NMR (400 MHz, CHLOROFORM-d) 5 = 9.70 - 9.62 (m, 1H), 7.96 - 7.88 (m, 1H), 7.57 (br d, J = 8.1 Hz, 1H), 5.71 - 5.62 (m, 2H), 4.45 - 4.39 (m, 1H), 4.32 - 4.26 (m, 1H), 3.86 - 3.79 (m, 1H), 3.78 - 3.74 (m, 1H), 3.35 - 3.30 (m, 3H), 0.82 - 0.79 (m, 10H), 0.03 - -0.01 (m, 6H)

[1223] LCMS (M+H+): 371.2

[1224] 5. Preparation of compound 5:

[1225]

[1226] To a solution of compound 4 (10 g, 45.20 mmol) in MeOH (400 mL) was added dropwise AcOH (2.71 g, 45.20 mmol) and Cpd.3A (16.75 g, 45.20) at 20°C, then NaBH3CN(4.26 g, 67.80 mmol) was added at 20 °C. The resulting mixture was stirred at 20°C for 2 hr. LCMS showed compound 4 was consumed completely desired mass was detected. The reaction mixture was added dropwise H2O 200 mL at 0 °C, and then diluted with water 200 mL and extracted with EtOAc (200 mL*3). The combined organic layers were dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (ISCO®; 330 g SepaFlash® Silica Flash Column, Eluent of 50-100% ethyl acetate: petroleum ether gradient @ 150 mL / min) (petroleum ether: ethyl acetate = 0: 1, Rf = 0.2). Compound 5 (5.5 g, 20.75% yield, 90% purity) was obtained as a yellow solid.

[1227] 1HNMR(400MHz, DMSO-d6) 5= 11.53 - 11.28 (m, 1H), 7.79 - 7.58 (m, 1H), 5.82 - 5.76 (m, 1H), 5.70 - 5.64 (m, 1H), 4.24 - 4.14 (m, 1H), 4.06 - 3.98 (m, 6H), 3.93 - 3.87 (m, 1H), 3.86 - 3.79 (m, 1H), 3.31 - 3.29 (m, 1H), 3.34 - 3.29 (m, 4H), 3.17 - 2.98 (m, 2H), 2.95 - 2.91 (m, 1H), 1.87 - 1.59 (m, 3H), 1.57 - 1.36 (m, 3H), 1.33 - 1.19 (m, 7H), 0.88 (d, J = 1.5 Hz, 9H), 0.11 - 0.07 (m, 6H), -1.56 - -1.83 (m, 1H)

[1228] LCMS (M+H+): 576.4

[1229] 6. Preparation of WV-NU-395:

[1230]

[1231] A mixture of compound 5 (10 g, 17.37 mmol), TBAF (1 M, 34.74 mL), and in THF (10 mL) was degassed and purged with N2 for 3 times, and then the mixture was stirred at 20°C for 2h under N2 atmosphere. LCMS showed compound 5 was consumed completely desired mass was detected. The mixture was concentrated under reduced pressure to give a residue. The residue was purified by prep-HPLC (neutral condition; WePure Biotech XP tC18 150*40*7um;mobile phase: [H2O(10mM NH4HCO3)-ACN]; gradient: 15%-55% B over 8.0 min ). WV-NU-395 (2.7 g, 32% yield, 95% purity) was obtained as a yellow solid.

[1232] 1HNMR(400MHz, DMSO-d6) 5= 11.45 - 11.31 (m, 1H), 7.88 - 7.59 (m, 1H), 5.88 - 5.72 (m, 1H), 5.69 - 5.60 (m, 1H), 5.20 - 5.12 (m, 1H), 4.06 - 3.97 (m, 5H), 3.87 - 3.77 (m, 2H), 3.39 - 3.35 (m, 3H), 3.13 - 2.89 (m, 3H), 3.00 - 2.87 (m, 1H), 1.84 - 1.63 (m, 3H), 1.63- 1.46 (m, 3H), 1.27 - 1.19 (m, 7H)

[1233] 31P NMR (400 MHz, DMSO-d6) 5 = 27.24 - 27.18 (m, 1P), 27.13 - 27.05 (m, 1P) LCMS (M+H+): 462.2, purity: 91.97%

[1234] EXAMPLE 20. Synthesis of WV-NU-418

[1235]

[1236] WV-NU-418

[1237] 1. Preparation of compound 1A:diethyl phosphonate

[1238]

[1239] A 1A

[1240] A mixture of compound A (20 g, 103.11 mmol), PPh3(8.11 g, 30.93 mmol) and Pd(OAc)2(2.31 g, 10.31 mmol) in EtOH (200 mL) was degassed and purged with N2 for 3 times, then 1-ethoxyphosphonoyloxy ethane (31.33 g, 226.84 mmol) and TEA (20.87 g, 206.21 mmol) was added to the mixture. The mixture was stirred at 78°C for 12 hr under N2 atmosphere. LCMS showed compound A was consumed completely and one main peak with desired mass was detected. The reaction mixture was quenched with Sat. NH4Cl (200 mL), and extracted with EtOAc 300 mL * 4. The combined organic layers were washed with brine 300 mL * 3, dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, petroleum ether: ethyl acetate = 1:0 to 0: 1, ethyl acetate: methanol = 1:0 to 10: 1). Compound 1 A (9.17 g, 43.56% yield) was obtained as a white solid.

[1241] 'H NMR (400 MHz, CHLOROFORM-d) 5 = 11.22 (br d, J = 2.0 Hz, 1H), 7.90 (d, J = 1.2 Hz, 2H), 4.18 - 4.00 (m, 4H), 1.32 (t, J = 7.0 Hz, 6H)

[1242] 31P NMR (162 MHz, CHLOROFORM-d) 5 = 15.00 (s, 1P)

[1243] LCMS (M+H+): 205.0

[1244] TLC: ethyl acetate: methanol = 10:l, Rf= 0.5

[1245]

[1246] To a solution of compound 1 (40 g, 154.90 mmol) in Pyridine (1000 mL) was added DMTC1 (57.73 g, 170.39 mmol). The mixture was stirred at 20 °C for 2 hr. TLC indicated compound 1 was consumed completely and one new spot formed. The reaction mixture was diluted with H2O 1500 mL and extracted with EtOAc 800 mL * 2. The combined organic layers were washed with brine 500 mL, dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by columnchromatography (SiCL, Petroleum ether: Ethyl acetate = 1:0 to 0:1). Compound 2 (58 g, 66.79% yield) was obtained as a yellow solid.

[1247] ’H NMR (400 MHz, DMSO-d6) 5 = 11.39 (s, 1H), 7.74 (d, J = 8.0 Hz, 1H), 7.40 - 7.36 (m, 2H), 7.32 (t, J = 7.6 Hz, 2H), 7.26 - 7.24 (m, 5H), 6.91 (d, J = 8.4 Hz, 4H), 5.82 (d, J = 3.4 Hz, 1H), 5.30 (d, J = 8.0 Hz, 1H), 5.23 (d, J = 7.0 Hz, 1H), 4.25 - 4.18 (m, 1H), 3.99 -3.93 (m, 1H), 3.83 - 3.81 (m, 1H), 3.74 (s, 6H), 3.41 (s, 3H), 3.32 - 3.28 (m, 1H), 3.26 -3.21 (m, 1H)

[1248] LCMS (M-H+): 559.2, LCMS purity: 97%

[1249] TLC: Petroleum ether: Ethyl acetate = 1:1, Rf = 0.6

[1250]

[1251] To a solution of compound 2 (56 g, 99.89 mmol) in DMF (800 mL) was added NaH (9.19 g, 229.76 mmol, 60% purity) at 0 °C under N2 for 1 h, and SEM-C1 (38.31 g, 229.76 mmol) was added to the mixture at 0 °C under N2. The mixture was stirred at 0-25 °C for 11 h. LCMS showed compound 2 was consumed completely. The reaction mixture was diluted with NH4CI 500 mL. The residue was diluted with H2O 1000 mL extracted with EtOAc 500 mL *3. The combined organic layers were dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, Petroleum ether: Ethyl acetate = 1:0 to 0:1). Compound 3 (60 g, 73.15% yield) was obtained as a yellow oil.

[1252] ’H NMR (400 MHz, DMSO-d6) 5 = 7.88 (d, J = 8.2 Hz, 1H), 7.39 - 7.35 (m, 2H), 7.32 (t, J = 7.6 Hz, 2H), 7.25 - 7.23 (m, 5H), 6.90 (d, J = 8.6 Hz, 4H), 5.84 (d, J = 2.6 Hz, 1H), 5.37 (d, J = 8.0 Hz, 1H), 5.19 (s, 2H), 4.69 - 4.66 (m, 2H), 4.30 - 4.25 (m, 1H), 4.12 - 4.09 (m, 1H), 4.00 - 3.98 (m, 1H), 3.74 (s, 6H), 3.61 - 3.58 (m, 2H), 3.57 - 3.48 (m, 3H), 3.41 (s, 3H), 0.87 - 0.80 (m, 5H), -0.04 (d, J = 2.0 Hz, 18H)

[1253] TLC: Petroleum ether: Ethyl acetate = 3:1, Rf = 0.5

[1254] 3. Preparation of compound 4:

[1255]

[1256] To a solution of compound 3 (60 g, 73.07 mmol) in MeOH (600 mL) was added AcOH (413.79 g, 6.89 mol) and H2O (103.45 g, 5.74 mol). The mixture was stirred at 20 °C for 2 hr. TLC indicated compound 3 was consumed completely and one new spot formed. The reaction mixture was concentrated under reduced pressure to remove MeOH. The residue was diluted with H2O 200 mL and extracted with EtOAc 100 mL * 3. The combined organic layers were washed with brine 100 mL, dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, Petroleum ether: Ethyl acetate = 1:0 to 0:1). Compound 4 (26 g, 68.59% yield) was obtained as a yellow oil.

[1257] ’H NMR (400 MHz, DMSO-d6) 5 = 8.09 (d, J = 8.2 Hz, 1H), 5.85 (d, J = 3.8 Hz, 1H), 5.80 (d, J = 8.0 Hz, 1H), 5.28 (t, J = 4.8 Hz, 1H), 5.20 (s, 2H), 4.70 (d, J = 1.0 Hz, 2H), 4.17 -4.12 (m, 1H), 4.02 - 3.99 (m, 1H), 3.92 (t, J = 4.2 Hz, 1H), 3.76 - 3.70 (m, 1H), 3.68 - 3.62 (m, 1H), 3.61 - 3.54 (m, 4H), 3.39 (s, 3H), 0.91 - 0.81 (m, 4H), 0.00 (s, 9H), -0.04 (s, 9H) TLC: Petroleum ether: Ethyl acetate = 1:1, Rf = 0.4

[1258] TLC: Petroleum ether: Ethyl acetate = 1:1, Rf = 0.4

[1259]

[1260] To a solution of compound 4 (29 g, 55.90 mmol) in Pyridine (300 mL) was added DMAP (682.96 mg, 5.59 mmol) and TosCl (15.99 g, 83.86 mmol). The mixture was stirred at 30 °C for 12 hr. LCMS showed compound 4 was consumed completely. The reaction mixture was concentrated under reduced pressure to remove pyridine. The residue was diluted with H2O 500 mL and extracted with EtOAc 300 mL * 3. The combined organic layers were washed with brine 300 mL, dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL,Petroleum ether: Ethyl acetate = 1:0 to 0: 1). Compound 5 (26 g, 69.11% yield) was obtained as a yellow oil.

[1261] 1H NMR (400 MHz, CHLOROFORM-d) 5 = 7.82 - 7.78 (m, 2H), 7.54 (d, J = 8.3 Hz, 1H), 7.38 (d, J = 8.1 Hz, 2H), 5.87 (s, 1H), 5.62 (d, J = 8.1 Hz, 1H), 5.40 - 5.37 (m, 1H), 5.36 - 5.32 (m, 1H), 4.71 (s, 2H), 4.46 - 4.41 (m, 1H), 4.36 - 4.32 (m, 1H), 4.30 - 4.26 (m, 1H), 4.00 (dd, J = 4.9, 8.7 Hz, 1H), 3.86 (d, J = 4.5 Hz, 1H), 3.75 - 3.71 (m, 1H), 3.71 - 3.67 (m, 2H), 3.66 (s, 1H), 3.60 (s, 3H), 2.47 (s, 3H), 1.00 - 0.96 (m, 2H), 0.96 - 0.91 (m, 2H), 0.03 - 0.01 (m, 9H), 0.00 (s, 9H)

[1262] TLC: Petroleum ether: Ethyl acetate = 3:1, Rf =0.55

[1263]

[1264] To a solution of compound 5 (26 g, 38.64 mmol) and 4-diethoxyphosphoryl-lH-pyrazole (9.15 g, 44.82 mmol) in DMF (200 mL) was added CS2CO3 (25.18 g, 77.27 mmol). The mixture was stirred at 80 °C for 12 hr. LCMS showed compound 5 was consumed completely and desired mass was detected. The reaction mixture was diluted with H2O 800 mL and extracted with EtOAc 300 mL * 3. The combined organic layers were washed with brine 500 mL *2, dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiCL, Petroleum ether: Ethyl acetate = 1:0 to 0:1). Compound 6 (20 g, 73.44% yield) was obtained as a colorless oil.

[1265] ’H NMR (400 MHz, CHLOROFORM-d) 5 = 7.84 (d, J = 2.0 Hz, 1H), 7.75 (s, 1H), 6.31 (d, J = 8.4 Hz, 1H), 5.83 (d, J = 1.2 Hz, 1H), 5.65 (d, J = 8.0 Hz, 1H), 5.33 (q, J = 9.6 Hz, 2H), 4.89 - 4.85 (m, 1H), 4.82 - 4.78 (m, 1H), 4.61 - 4.55 (m, 1H), 4.54 - 4.48 (m, 1H), 4.41 - 4.35 (m, 1H), 4.15 - 4.09 (m, 4H), 4.00 (dd, J = 5.3, 8.6 Hz, 1H), 3.78 - 3.72 (m, 2H), 3.69 - 3.62 (m, 3H), 3.55 (s, 3H), 1.37 - 1.30 (m, 6H), 1.00 - 0.91 (m, 4H), 0.03 - 0.00 (m, 9H), -0.01 - -0.04 (m, 9H)

[1266] 31P NMR (162 MHz, CHLOROFORM-d) 5 = 13.01 (s, 1P)

[1267] LCMS (M+H+): 705.2, LCMS purity: 97%

[1268] TLC: Petroleum ether: Ethyl acetate = 0:1, Rf = 0.25

[1269]

[1270] 6 WV-NU-418

[1271] To a solution of compound 6 (20 g, 28.37 mmol) in DCM (300 mL) was added TFA (32.35 g, 283.73 mmol, 21.08 mL). The mixture was stirred at 20 °C for 12 hr. LCMS showed compound 6 was consumed completely and desired mass was detected. The reaction mixture was concentrated under reduced pressure to remove DCM. The residue was purified by column chromatography (SiCE, Petroleum ether: Ethyl acetate = 1:0 to 0: 1, Ethyl acetate: Methanol = 1:0 to 8:1). WV-NU-418 (10.74 g, 85.18% yield) was obtained as a white solid.

[1272] ’H NMR (400 MHz, DMSO-d6) 5 = 11.40 (s, 1H), 8.15 (d, J = 1.9 Hz, 1H), 7.75 (s, 1H), 7.43 (d, J = 8.1 Hz, 1H), 5.80 (d, J = 5.0 Hz, 1H), 5.62 (d, J = 8.0 Hz, 1H), 5.44 (d, J = 5.8 Hz, 1H), 4.54 - 4.42 (m, 2H), 4.14 (qd, J = 5.0, 9.8 Hz, 2H), 4.00 - 3.92 (m, 4H), 3.80 (t, J = 4.9 Hz, 1H), 3.35 (s, 3H), 1.21 (dt, J = 1.7, 7.0 Hz, 6H)

[1273] 31P NMR (162 MHz, CHLOROFORM-d) 5 = 13.34 (s, 1P)

[1274] LCMS (M+H+): 445.1, LCMS purity: 96.64%

[1275] TLC: Ethyl acetate: Methanol = 10:l, Rf= 0.3

[1276] EXAMPLE 21. Synthesis of WV-NU-380

[1277]

[1278] WV-NU-380

[1279] Synthetic Scheme for (WV-NU-380)

[1280]

[1281] WV-NU-380

[1282] Preparation of N-(9-((2R,3R,4S,5S)-4-hydroxy-5-(iodomethyl)-3-methoxytetrahydrofuran-2-yl)-9H-purin-6-yl)benzamide (WV-NU-380.02):

[1283] To a stirred solution of WV-NU-380.01 (10 g, 0.0259 mol) in N- Methyl -2- pyrrolidone (100 mL, 10 vol.), was added iodine (19.7 g, 0.07793 mol), PPh3 (20 g, 0.07792 mol.) and imidazole (10.5 g 0.1558 mol.) at 25°C. Then resulting mixture was stirred at rt for 4 h. Progress of the reaction was monitored by TLC. After completion, the reaction was quenched with saturated sodium thiosulfate (100 mL), extracted with EtOAc (2 x 100 mL), washed with cold brine (2 X 80 mL), dried over Na2SO4 and concentrated under reduced pressure. The crude material was purified by column chromatography over silica-gel (230-400 mesh) eluted in 4% MeOH in DCM to get an off white solid (WV-NU-380.02) (7.3 g, 57%), TLC Mobile phase details: 7% MeOH in DCM.1H NMR (400 MHz, DMSO-ds): 5 in ppm = 11.26 (s, 1H), 8.79 (s, 1H), 8.75 (s, 1H), 8.05 (m, 2H), 7.66 (t, 1H, JI = 7.4 Hz), 7.56 (m, 2H), 6.19 (d, 1H, Ji = 5.8 Hz), 5.64 (d, 1H, JI = 5.6 Hz), 4.68 (t, 1H, JI = 5.4 Hz), 4.43 (dd, 1H, JI = 8.9 Hz, J2 = 5.2 Hz), 4.07 (m, 1H), 3.65 (dd, 1H, JI = 10.5 Hz, J2 = 6.0 Hz), 3.52 (dd, 1H, JI = 10.5 Hz, J2 =6.9 Hz), 3.36 (s, 3H). MS: m / z calcd for C18H18IN5O4, 495.3; found 496.5, [M+H]+.

[1284] Preparation of N-(9-((2R,3R,4R,5R)-5-(azidoniethyl)-4-hydroxy-3-methoxytetrahydrofuran-2-yl)-9H-purin-6-yl)benzamide (WV-NU-362-B):

[1285] To a stirred solution of (WV-NU-380.02) (18 g, 0.0363 mol) in dry DMF (288 mL, 16 vol.) was added sodium azide (2.36 g, 0.03634 mol) at 0°C. The resulting mixture wasstirred at 40°C and kept for 4 h. Progress of the reaction was monitored by TLC. After that reaction was quenched with ice water (100 mL), extracted with EtOAc (3 x 80 mL), washed with cold brine (2 X 70 mL), dried over Na2SO4 and concentrated under reduced pressure. The crude was purified by column chromatography over silica-gel (230-400 mesh) eluted in 2% MeOH in DCM to get off white solid (WV-NU-380.03) (10.5 g, 70%) TLC Mobile phase details: 7% MeOH in DCM.1H NMR (500 MHz, DMSO-d6): 8 in ppm = 11.24 (s, 1H), 8.79 (s, 1H), 8.74 (s, 1H), 8.05 (m, 2H, JI = 7.6 Hz), 7.65 (t, 1H, JI = 7.6 Hz), 7.56 (t, 2H, JI = 7.6 Hz), 6.19 (d, 1H, JI = 5.5 Hz), 5.53 (d, 1H, JI = 5.5 Hz), 4.60 (t, 1H, JI = 5.2 Hz), 4.44 (q, 1H, JI = 5.0 Hz), 4.12 (m, 1H), 3.72 (q, 1H, JI = 6.7 Hz), 3.61 (dd, 1H, JI = 13.4 Hz, J2 =3.8 Hz), 3.38 (s, 3H). MS: m / z calcd for C18H18N8O4, 410.4; found 411.6 [M+H]+.

[1286] Preparation of (((l-(((2R,3R,4R,5R)-5-(6-benz.ainido-9H-purin-9-yl)-3-hydroxy-4-methoxy tetrahydrofuran-2-yl)methyl)-LH-l,2,3-triazol-4-yl)phosphoryl)bis(oxy))bis(methylene) bis(2,2dimethylpropanoate) (WV-NU-380):

[1287] The compound (WV-NU-380.03) (10 g, 0.0243 mol) and 5A (12.2 g, 0.0243 mol) was dissolved in a mixture of solvent (THF: Water) (1: 1) (50 mL, 5 vol.) and water (50 mL, 5 vol.). Then the solution was degassed with nitrogen for 30 minutes at rt. After that sodium ascorbate (0.965 g, 0.00487 mol), CUSO4.5H2O (0.64 g, 0.00256 mol) was added to the solution. Then reaction mixture was allowed to 65°C for 6 h. Progress of the reaction was monitored by TLC. The reaction mass was diluted with EtOAc (80 mL), washed with water (2 x 30 mL), dried over Na2SO4and concentrated under reduced pressure. The crude mass was purified by column chromatography over silica-gel (230-400 mesh) eluted in 2% MeOH in EtOAC to get light green solid (WV-NU-380) (9.2 g, 50%) TLC Mobile phase details: 7% MeOH in DCM. 'H NMR (500 MHz, DMSO-d6): 6 in ppm = 11.24 (s, 1H), 8.76 (d, 2H, JI = 19.3 Hz), 8.67 (s, 1H), 8.05 (d, 2H, JI = 7.6 Hz), 7.66 (t, 1H, JI = 7.2 Hz), 7.56 (t, 2H, JI = 7.6 Hz), 6.18 (d, 1H, JI = 4.8 Hz), 5.66 (m, 5H), 4.92 (m, 2H), 4.55 (td, 2H, JI = 9.6 Hz, JI = 4.6 Hz), 4.39 (m, 1H), 3.39 (s, 3H), 1.02 (s, 18H). MS: m / z calcd for C32H4IN80IIP, 744.7; found 745.9 [M+H]+

[1288] calcd for C14H23O7P, 334.3; found 335.1 [M+H]+.

[1289] EXAMPLE 22. Synthesis of WV-NU-381

[1290]

[1291] WV-NU-381

[1292] Synthetic Scheme for (WV-NU-381)

[1293]

[1294] C, 6, 50%.

[1295] WV-NU-381 Preparation of N-(l-((2R,3R,4S,5S)-4-hydroxy-5-(iodomethyl)-3-methoxytetrahydrofuran-2-yl)-2-oxo-l,2-dihydropyriinidin-4-yl)acetamide (H l - L -381-02):

[1296] To a stirred solution of WV-NU-380-01 (20 g, 0.0668 mol) in dry THF (300 mL, 15 vol.), was added iodine (33.8 g, 0.1337 mol), PPh3 (35 g, 0.1337 mol.) and imidazole (27.2 g 0.4016 mol.) at 20°C. Then resulting mixture was stirred at rt for 20 h. Progress of the reaction was monitored by TLC. After completion, the reaction was quenched with saturated sodium thiosulfate (200 mL), extracted with EtOAc (2 x 150 mL), washed with brine (1 x 100 mL), dried over Na2SO4 and concentrated under reduced pressure. The crude compound was purified by column chromatography over silica-gel (230-400 mesh) eluted in 3% MeOH in DCM to get an off white solid (WV-NU-381-02) (17 g, 63%), TLC Mobile phase details: 5% MeOH in DCM. 'H NMR (500 MHz, DMSO-d6): 8 in ppm = 10.96 (s, 1H), 8.11 (d, 1H, JI = 7.6 Hz), 7.25 (s, 1H), 5.90 (d, 1H, JI = 2.8 Hz), 3.91 (t, 3H, JI = 3.1 Hz), 3.59 (dd, 1H, JI = 10.3 Hz, J2 = 3.4 Hz), 3.49 (m, 1H), 3.11 (s, 3H), 2.11 (s, 3H). MS: m / z calcd for C12H16IN3O5, 409.18; found 410.1, [M+H]+.Preparation of N-(l-((2R,3R,4R,5R)-5-(azidomethyl)-4-hydroxy-3- ethoxytetrahydrofuran-2-yl)-2-oxo-l,2-dihydropyriinidin-4-yl) acetamide (WV-NU-381-03):

[1297] To a stirred solution of (WV-NU-381-02) (17 g, 0.0415 mol) in dry DMF (272 mL, 16 vol.) was added sodium azide (3.2 g, 0.0498 mol) at 0°C. Then resulting mixture was stirred at 40°C for 5 h. Progress of the reaction was monitored by TLC. Then reaction was quenched with ice water (150 mL), extracted with EtOAc (2 x 150 mL), washed with cold brine (2 X 100 mL), dried over ISfeSCU and concentrated under reduced pressure. The crude mass was purified by column chromatography over silica-gel (230-400 mesh) eluted in 3% MeOH in DCM to get off white solid (WV-NU-381-03) (9 g, 66%) TLC Mobile phase details: 7% MeOH in DCM.1H NMR (500 MHz, DMSO-d6): 8 in ppm = 11.94 (s, 1H), 8.11 (t, 1H, JI = 7.2 Hz), 7.25 (q, 1H, JI = 4.1 Hz ), 5.88 (dd, 1H, JI = 15.1 Hz, J2 = 2.8 Hz), 5.39 (dd, 1H, JI = 41.0 Hz, J2 = 5.9 Hz), 3.98 (d, 2H, JI = 2.8 Hz), 3.91 (t, 1H, JI = 2.8 Hz), 3.83 (q, 1H, JI = 2.5 Hz), 3.66 (m, 2H), 3.43 (d, 3H, JI = 13.1 Hz), 2.11 (s, 3H). MS: m / z calcd for C12H16N6O5, 324.3; found 325.36 [M+H]+.

[1298] Preparation of (((l-(((2R,3R,4R,5R)-5-(4-acetamido-2-oxopyrimidin-l (2H)-yl)-3-hydroxy-4-methoxytetrahydrofuran-2-yl)niethyl)-lH-l,2,3-triazol-4-yl)phosphoryl)bis(oxy))bis-(methylene) bis(2,2-dimetbylpropanoate) (WV-NU-381): To a stirred solution of (WV-NU-381-03) (9 g, 0.0227 mol) and (WV-NU-380-B) (13.9 g 0.0416 mol) in mixture of solvent (1:1) THF (45 mL, 5 vol.), water (45 mL, 5 vol.) was degassed with nitrogen atmosphere for 25 minutes. Then added sodium ascorbate (0.1.09 g, 0.0055 mol), CUSO4.5H2O (0.69 g, 0.00277 mol) at rt. The reaction mixture was stirred at 65°C for 6 h. Progress of the reaction was monitored by TLC. The reaction mixture was cooled to rt and concentrated under reduced pressure The crude mass was purified by column chromatography over silica-gel (230-400 mesh) eluted in 3% MeOH in EtOAC to get light green solid (WV-NU-381) (9.2 g, 50%) TLC Mobile phase details: 7% MeOH in DCM.1H NMR (400 MHz, DMSO-d6): 6 in ppm = 10.95 (s, 1H), 8.74 (s, 1H), 8.04 (d, 1H, JI = 7.6 Hz), 7.26 (d, 1H, JI = 6.9 Hz), 5.80 (d, 1H, JI = 2.8 Hz), 5.70 (s, 2H), 5.67 (s, 2H), 5.51 (d, 1H, JI = 6.9 Hz), 4.85 (m, 2H), 4.24 (m, 1H), 4.07 (d, 1H, JI = 6.2 Hz), 3.88 (m, 1H, JI = 3.4 Hz), 3.44 (s, 3H), 2.11 (s, 3H), 1.06 (s, 18H). MS: m / z calcd for C26H39N6O12P, 658.6; found 660.0 [M+H]+.EXAMPLE 23. Synthesis of WV-NU-382

[1299]

[1300] WV-NU-382

[1301] Synthetic Scheme for (WV-NU-382)

[1302]

[1303] C, 6 h, 61 %.

[1304] WV-NU-382Preparation of N-(9-((2R,3R,4S,5S)-4-hydroxy-5-(iodomethyl)-3-methoxytetrahydrofuran-2-yl)-6-oxo-6,9-dihydro-lH-purin-2-yl)isobutyramide (WV-NU-382-02):

[1305] To a stirred solution ofWV-NU-380-01 (25 g, 0.0681 mol) in dry THF (375 mL, 15 vol.), was added iodine (34.4 g, 0.1362 mol), PPh (35.6 g, 0.1362 mol.) and imidazole (27.8 g 0.4087 mol.) at 25°C. Then resulting mixture was stirred at rt for 20 h. Progress of the reaction was monitored by TLC. After completion, the reaction was quenched with saturated sodium thiosulfate (150 mL), extracted with EtOAc (2 x 150 mL), washed with brine (1 x 100 mL), dried over Na2SO4 and concentrated under reduced pressure. The crude compound was purified by column chromatography over silica-gel (230-400 mesh) eluted in 5% MeOH in DCM to get off white solid (WV-NU-382-02) (20 g, 61%), TLC Mobile phase details: 7% MeOH in DCM. 'H NMR (500 MHz, DMSO-d6): 5 in ppm = 12.08 (s, 1H), 11.64 (s, 1H), 8.29 (s, 1H), 5.93 (d, 1H, JI = 6.2 Hz), 5.57 (d, 1H, JI = 5.5 Hz), 4.47 (t, 1H, JI = 5.9 Hz), 4.32 (q, 1H, JI = 3.9 Hz), 4.02 (td, 1H, JI = 6.7 Hz, J2 = 3.0 Hz), 3.58 (dd, 1H, JI = 10.3 Hz, J2 = 6.9 Hz), 3.44 (dd, 1H, JI = 10.3 Hz, J2 = 6.9 Hz), 3.34 (s, 3H), 2.76 (m, 1H), 1.13 (d, 6H, JI = 6.2 Hz), MS: m / z calcd for C15H20IN5O5, 477.26; found 478.48, [M+H]+.Preparation of N-(9-((2R,3R,4R,5R)-5-(azidomethyl)-4-hydroxy-3-methoxytetrahydrofuran-2-yl)-6-oxo-6,9-dihydro-lH-purin-2-yl)isobutyramide (WV-NU-382-03):

[1306] To a stirred solution of (WV-NU-380-02) (20 g, 0.0417 mol) in dry DMF (320 mL, 16 vol.) was added sodium azide (3.28 g, 0.0503 mol) at 0°C. The resulting mixture was stirred 50°C and kept for 5 h. Progress of the reaction was monitored by TLC. Then reaction was quenched with ice water (200 mL), extracted with EtOAc (2 x 100 mL), washed with cold brine (2 X 100 mL), dried over Na2SO4 and concentrated under reduced pressure. The crude mass was purified by column chromatography over silica-gel (230-400 mesh) eluted in 3% MeOH in DCM to get off white solid (WV-NU-382-03) (11.5 g, 70%) TLC Mobile phase details: 7% MeOH in DCM. ‘HNMR^OMHz, DMSO-d6): 8 in ppm = 12.10 (s, 1H), 11.63 (s, 1H), 8.30 (s, 1H), 5.93 (d, 1H, JI = 6.2 Hz), 5.47 (d, 1H, JI = 5.1 Hz), 4.39 (dd, 1H, JI = 6.0 Hz, J2 = 5.2 Hz), 4.30 (dd, 1H, JI = 8.6 Hz, J2 = 4.9 Hz), 4.05 (m, 1H), 3.67 (q, 1H, JI = 6.6 Hz), 3.58 (dd, 1H, JI = 13.2 Hz, J2 = 4.1 Hz), 3.35 (s, 3H), 2.77 (m, 1H), 1.13 (dd, 6H, JI = 6.9 Hz, JI = 0.8 Hz), MS: m / z calcd for C15H20N8O5, 392.38; found 393.5, [M+H]+.

[1307] Preparation of (((l-(((2R,3R,4R,5R)-3-hydroxy-5-(2-isobutyramido-6-oxo-l,6-dihydro-9H-purin-9-yl)-4-methoxytetrahydrofuran-2-yl)methyl)-lH-l,2,3-triazol-4-yl)phosphoryl) bis(oxy))bis(methylene) bis(2,2-dimetbylpropanoate) (WV-NU-382): To a stirred solution of (WV-NU-380-03) (11.5 g, 0.0293 mol) and (WV-NU-380-B) (14.6 g, 0.044 mol. ) in mixture of solvent (1:1) THF (57.5 mL, 5 vol.), water (57.5 mL, 5 vol.) was degassed with nitrogen atmosphere for 35 minutes. Then added sodium ascorbate (1.11 g, 0.00561 mol), CUSO4.5H2O (0.73 g, 0.00293 mol) at rt. The reaction mixture was stirred at 65°C for 6 h. Progress of the reaction was monitored by TLC. The reaction mixture was cooled to rt and concentrated under reduced pressure The crude mass was purified by column chromatography over silica-gel (230-400 mesh) eluted in 3% MeOH in EtOAC to get light green solid (WV-NU-382) (13.1 g, 61%) TLC Mobile phase details: 7% MeOH in DCM. Tf NMR (500 MHz, DMSO-d6): 6 in ppm = 12.10 (s, 1H), 11.60 (s, 1H), 8.66 (s, 1H), 8.29 (s, 1H), 5.93 (d, 1H, JI = 5.5 Hz), 5.65 (m, 5H), 4.84 (m, 2H), 4.46 (q, 1H, JI = 4.1 Hz), 4.36 (t, 1H, JI = 5.5 Hz), 4.32 (m, 1H), 3.36 (s, 3H), 2.75 (m, 1H), 1.11(d, 6H, JI = 6.9Hz), 1.02 (s, 18H). MS: m / z calcd for C29H43N8O12P, 726.68; found 725.8 [M-H]+.EXAMPLE 24. Synthesis of WV-NU-389

[1308]

[1309] Preparation of (2R,3R,3aS,9aR)-3-hydroxy-2-(hydroxymethyl)-2,3,3a,9a-tetrahydro-6H-furo[2',3':4,5] oxazolo[3,2-c]pyrimidine-6,8(7H)-dione (WV-NU-302-02):

[1310] To a stirred solution of Uridine (30 g, 0.122 mol) and diphenyl carbonate (26 g, 0.1229 mol.) in dry DMF (36 mL, 1.2 vol.) was added sodium bicarbonate (258 mg, 0.00307 mol) stirred at 130°C for 3 h. Progress of the reaction was monitored by TLC. Then reaction mixture was cooled to rt, precipitated product was observed, filtered and washed with cold methanol (2 x 15 mL), dried under vacuum to get as off white solid (WV-NU-301-02) (21 g, 70%). TLC Mobile phase details: 15% MeOH in DCM. 'H NMR (500 MHz, DMSO-d6): 8 in ppm =7.83 (d, 1H, JI = 6.9 Hz), 6.30 (d, 1H, JI = 6.2 Hz), 5.88(s, 1H), 5.84 (d, 1H, JI = 6.9 Hz), 5.19 (d, 1H, JI = 5.5 Hz), 4.98 (t, 1H, JI = 5.2 Hz), 4.38 (s, 1H), 4.07 (t, 1H, JI = 4.5 Hz), 3.28 (m, lH) 3.18 (m, 1H).

[1311] Preparation of (2R,3R,3aS,9aR)-2-(((tert-butyldiphenylsilyl)oxy)methyl)-3-hydroxy- 2,3,3a, 9a- tetrahydro-6H-furo[2 ',3 ':4,5]oxazolo[3,2-c]pyrinudine-6,8(7H)-dione(WV- NU-301-03):To a stirred solution of (WV-NU-301-02) (40 g, 0.165 mol) and DMAP (2 g, 0.0165 mol.) in anhydrous pyridine (200 mL, 5 vol.) was added TBDPSC1 (63 mL, 0.247 mol.) dropwise over a period of 30 mins, at 0°C. Above reaction mixture was stirred at rt for 30 h. Progress of the reaction was monitored by TLC. The reaction was diluted with cold sat. NaHCO3 (150 mL) and extracted with DCM (2 x 200 mL), washed with brine (1 x 150 mL) solution, dried over Na2SO4 and concentrated under reduced pressure. The crude compound was purified by column chromatography over silica-gel (230-400 mesh) eluted in 4% MeOH in DCM to afford an off-white solid. (WV-NU-301-03) (38 g, 48%). TLC Mobile phase details: 10% MeOH in DCM. ‘HNMR (400 MHz, DMSO-d6): 8 in ppm =7.92 (d, 1H, JI = 7.6 Hz), 7.53 (m, 4H), 7.43 (m, 7H), 6.32 (d, 1H, JI = 5.5 Hz), 6.02 (d, 1H, JI = 4.8 Hz), 5.87 (d, 1H, JI = 7.6 Hz), 5.26 (m, 1H), 4.45 (q, 1H, JI = 2.8Hz), 4.17 (m, 1H, Hz), 3.59 (q, 1H, JI = 5.3Hz), 3.47 (q, 1H, JI = 6.0Hz) 3.08 (d, 1H, JI = 6.9Hz),0.92 (s, 9H)

[1312] Preparation of l-((2R,3R,4R,5R)-3-(hexadecyloxy)-4-hydroxy-5-(hydroxymethyl) tetrahydrofuran-2-yl)pyrinidine-2,4(lH,3H)-dione (WV-NU-301-05):

[1313] To a stirred solution of 1-Hexadecanol (130.6 g, 0.541 mol)) in anhydrous diglyme (100 mL, 2.8 vol.) was added Trimethylaluminum (112.4 mL, 0.225 mol, 2M) dropwise over a period of 40 min. The resulting mixture was heated to 120°C and stirred for 2 h. Then the mass was allowed to rt and (WV-NU-301-03) (36 g, 0.075 mol) was added, stirred at 130°C for 16 h. Progress of the reaction was monitored by TLC. The reaction mixture was diluted 10% H3P04 (500 mL) and EtOAc (300 mL), organic layer was separated washed with 5% NaCl (100 mL), dried over Na2SO4 and concentrated under vacuum to afford as a gummy syrup (64 g, crude). The syrup was dissolved in THF (360 mL, 10 vol.), was added triethylamine hydrofluride (48 mL, 0.30 mol.), stirred rt for 3 days. Progress of the reaction was monitored by TLC. The reaction was diluted 5% NaCl (250 mL) and EtOAc (300 mL), organic layer was separated washed with sat. NaCl solution (1 x 150 mL), dried overNa2SO4 and concentrated under reduced pressure. The crude compound was purified by column chromatography over silica-gel (230-400 mesh) eluted in 3% MeOH in DCM to afford an off-white solid. (WV-NU-301-05) (14.3 g, 40%). TLC Mobile phase details: 10% MeOH in DCM. ‘HNMR (500 MHz, DMSO-d6): 6 in ppm =11.33 (d, 1H, JI = 1.4 Hz), 7.94 (d, 1H, JI = 7.6 Hz), 5.84 (d, 1H, JI = 4.8 Hz), 5.64 (dd, 1H, JI = 7.9 Hz, J2 = 1.7 Hz), 5.13 (t, 1H, JI = 5.2 Hz), 5.04 (d, 1H, JI = 6.2 Hz), 4.09 (dt, 2H, JI = 10.0 Hz, JI = 4.8 Hz), 3.85 (t, 2H, JI = 4.8 Hz), 3.63 (dq, 1H, JI = 12.2 Hz, J2 = 2.8 Hz), 3.56 (m, 2H), 3.44 (m, 1H),3.17 (d, 1H, JI = 5.5 Hz), 1.47 (q, 2H, JI = 6.7 Hz), 1.23 (s, 34H), 0.85 (t, 3H, JI = 6.5 Hz), MS: m / z calcd for C25H44N2O6, 468.6; found 467.3 (M-H+).

[1314] Preparation of l-((2R,3R,4S,5S)-3-(hexadecyloxy)-4-hydroxy-5-(iodomethyl)tetrahydrofuran-2-yl)pyrinudine-2,4(lH,3H)-dione (WV-NU-389-01):

[1315] To a stirred solution of WV-NU-301.05 (14 g, 0.0299 mol) in dry THF (140 mL, 10 vol.), was added iodine (15 g, 0.0598 mol), PPhi (15.6 g, 0.0598 mol.) and imidazole (12.2 g 0.178 mol.) at rt. Then resulting mixture was stirred at rt for 20 h. Progress of the reaction was monitored by TLC. After completion, the reaction was quenched with saturated sodium thiosulfate (120 mL), extracted with EtOAc (2 x 100 mL), washed with cold brine (1 x 100 mL), dried over Na2SO4 and concentrated under reduced pressure. The crude compound was purified by column chromatography over silica-gel (230-400 mesh) eluted in 4% MeOH in DCM to get off white solid (WV-NU-389-01) (10.5 g, 61%), TLC Mobile phase details: 7% MeOH in DCM. 'H NMR (400 MHz, DMSO-d6): 8 in ppm = 11.39 (s, 1H), 7.69 (d, 1H, JI = 8.3 Hz ), 5.86 (d, 1H, JI = 5.5 Hz), 5.68 (dd, 1H, JI = 5.3 Hz, JI = 2.1 Hz), 5.34 (d, 1H, JI = 6.2 Hz), 4.07 (m, 1H), 4.05 (t, 1H, JI = 5.5 Hz), 3.99 (q, 1H, JI = 5.5 Hz), 3.86 (q, 1H, JI = 5.5 Hz), 3.56 (m, 2H), 1.46 (q, 1H, JI = 6.4 Hz), 1.26 (s, 28H), 0.85 (t, 3H,

[1316]

[1317] = 6.9 Hz),. MS: m / z calcd for C25H43IN2O5, 578.53; found 577.53, [M-H]+.

[1318] Preparation of l-( (2R, 3R, 4R, 5R)-5-(azidomethyl)-3- (hexadecyloxy)-4-hydroxytetrahydrofuran-2-yl)pyriniidine-2,4(lH,3H)-dione (WV-NU-389-02):

[1319] To a stirred solution of (WV-NU-389-01) (13 g, 0.0224 mol) in dry DMF (208 mL, 16 vol.) was added sodium azide (1.75 g, 0.0269 mol) at 0°C. The resulting mixture was stirred 50°C and kept for 4 h. Progress of the reaction was monitored by TLC. Then reaction was quenched with ice water (150 mL), extracted with EtOAc (2 x 150 mL), washed with cold brine (2 X 100 mL), dried over Na2SO4 and concentrated under reduced pressure. The crude mass was purified by column chromatography over silica-gel (230-400 mesh) eluted in 40% EtOAc in Hexane to get off white solid (WV-NU-389-02) (7.5 g, 68%) TLC Mobile phase details: 60% EtOAc in Hexane. 'HNMR (500 MHz, DMSO-d6): 6 in ppm = 11.39 (s, 1H), 7.70 (d, 1H, JI = 8.3 Hz), 5.82 (d, 1H, JI = 4.8 Hz), 5.67 (d, 1H, JI = 8.3 Hz), 5.25 (d, 1H, JI = 6.2 Hz), 4.02 (q, 1H, JI = 5.3 Hz), 3.98 (t, 1H, JI = 52 Hz), 3.93 (q, 1H, JI = 5.0 Hz), 3.58 (m, 1H), 3.44 (m, 1H), 1.48 (t, 2H, JI = 6.5 Hz) 1.23 (s, 28H), 0.85 (t, 3H, JI = 6.9Hz). MS: m / z calcd for C25H43N5O5, 493.65; found 494.56 [M+H]+.

[1320] Preparation of (((l-(((2R,3R,4R,5R)-5-(2,4-dioxo-3,4-dihydropyrimidin-l (2H)-yl)-4-(hexadecyloxy)-3-hydroxytetrahydrofuran-2-yl)methyl)-lH-l,2,3-triazol-4-yl)phosphoryl)bis(oxy) )bis (methylene) bis(2,2-dimethylpropanoate)) (WV-NU-389): To a stirred solution of (WV-NU-389-02) (11 g, 0.0223 mol) and (WV-NU-380-B) (11.17, 0.033 mol) in mixture of solvent (1:1) THF (55 mL, 5 vol.), water (55 mL, 5 vol.) was degassed with nitrogen atmosphere for 30 minutes. Then added sodium ascorbate (0.88 g, 0.00446 mol), CUSO4.5H2O (0.55 g, 0.00223 mol) at rt. The reaction mixture was stirred at 65°C for 6 h. Progress of the reaction was monitored by TLC. The reaction mass was diluted EtOAc (100 mL), washed with water (2 x 30 mL), dried over Na2SO4 and concentrated under reduced pressure The crude compound was purified by column chromatography over silica-gel (230-400 mesh) eluted in 60% EtOAC in Hexane to get gummy syrup (WV-NU-389) (10.5 g, 56%) TLC Mobile phase details: 70% EtOAC in Hexane. ' H NMR (500 MHz, DMSO-de): 8 in ppm = 11.40 (d, 1H, JI = 2.1 Hz), 8.69 (s, 1H), 7.64 (d, 1H, JI = 8.3 Hz), 5.79 (d, 1H, JI = 4.8 Hz), 5.67 (m, 4H), 5.40 (d, 1H, JI = 5.5 Hz), 4.79 (m, 2H), 4.19 (m, lH), 4.00 (t, 1H, JI = 5.2 Hz), 3.58 (m, 1H), 3.45 (m, 1H), 1.48 (t, 2H, JI = 6.5 Hz), 1.23 (s, 28H), 1.07 (s, 18H), 0.85 (t, 3H, JI = 6.9 Hz). MS: m / z calcd for C39H66N5O12P, 827.95; found 829.00 [M+H]+.

[1321] EXAMPLE 25. Synthesis of WV-NU-372, WV-NU-383

[1322]

[1323]

[1324] Experimental Procedure:

[1325] 1. Preparation of compound 2A:

[1326]

[1327] For two batches: To a solution of compound 1A (50 g, 146.88 mmol), EtsN (44.59 g, 440.64 mmol, 61.33 mL) in DCM (500 mL) was added MsCI (24.505 g, 213.92 mmol, 16.56 mL) at 0 °C under N2, the reaction was stirred at 20 °C for 2 h. LCMS showed compound 1A was consumed completely. The reaction was poured into ice water (500 mL) at 0 °C, extracted with DCM (500 * 3 mL), combined organic layers was washed with brine, dried over Na2SO4 and evaporated. Compound 2A (100 g, crude) was obtained as yellow oil.LCMS: 243.0

[1328] 2. Prep2. Preparation of compound 3A:

[1329]

[1330] 2A 3A

[1331] For two batches: To a solution of diethyl phosphite (28.86 g, 208.99 mmol, 26.92 mL) in THF (500 mL) was added LiHMDS (1 M, 208.99 mL) at -70 °C under N2 dropwise, then compound 2A (50 g, 139.33 mmol) in THF(300 mL) was added at -70 °C, the reaction was stirred at 20 °C for 12 h. TLC indicated compound 2A was consumed completely and one new spot formed. The reaction was added sat. NH4CI (1000 mL) at 0 °C, extracted with EtOAc (1000 * 3 mL), combined organic layer washed with brine, dried over ISfeSCU and evaporated to dryness. The residue was purified by column chromatography (SiO2, Ethyl acetate: Methanol = 1:0 to 5:1). Compound 3A (9.2 g, 5.74% yield) was obtained as a yellow solid.

[1332] ’H NMR (400 MHz, CHLOROFORM-d) δ = 7.40 (s, 1 H), 7.37 - 7.29 (m, 9 H), 7.20 - 7.10 (m, 6 H), 6.83 (d, J = 1.8 Hz, 1 H), 4.10 - 3.97 (m, 4 H), 3.28 - 3.10 (m, 2 H), 1.26 -1.20 (m, 6 H)

[1333] LCMS (M+H+): 461.1, LCMS purity: 96%

[1334] TLC: Ethyl acetate: Methanol = 10:l, Rf= 0.19

[1335] 3. Preparation of compound 4 A:

[1336]

[1337] 3A

[1338] To a solution of compound 3A (9 g, 19.54 mmol) in DCM (100 mL) was added TFA (30.70 g, 269.24 mmol, 20 mL) and triethylsilane (2.27 g, 19.54 mmol, 3.12 mL), the reaction was stirred at 20 °C for 4 h. LCMS showed compound 3A was consumed completely and desired mass was detected. The reaction was concentrated in vacuum. The residue was purified by column chromatography (SiO2, Ethyl acetate: Methanol = 1:0 to 2: 1). Compound 4A (4 g, 83.48% yield) was obtained as a yellow oil.

[1339] 1H NMR (400 MHz, DMSO-d6) 8 = 8.57 (s, 1 H), 7.29 (br d, J = 3.0 Hz, 1 H), 4.08 - 3.89 (m, 4 H), 3.40 - 3.25 (m, 2 H), 1.20 (t, J = 7.0 Hz, 6 H)LCMS (M+H+): 219.1, LCMS purity: 89%

[1340] TLC: Ethyl acetate: Methanol = 4:1, Rf= 0.1

[1341] 4. Preparation of compound 2:

[1342]

[1343] Compound 1 (50 g, 193.63 mmol) in pyridine (500 mL) was added DMTrCI (72.17 g, 212.99 mmol), the reaction was stirred at 25 °C for 2 h. TLC indicated compound 1 was consumed completely and one new spot formed. The reaction was concentrated in vacuum, then added water (300 mL), extracted with Ethyl acetate (300 mL * 2), the combined extracts was dried over Na2SO4, filtered and concentrated. The residue was purified by column chromatography (SiCL, Commercial hexanes: Ethyl acetate = 1: 0 to 0: 1). Compound 2 (70 g, 57.39% yield, 89% purity) was obtained as a yellow solid.

[1344] ’H NMR (400 MHz, CHLOROFORM-d) 8 = 8.77 (s, 1 H), 8.05 (d, J = 8.0 Hz, 1 H), 7.43 - 7.37 (m, 2 H), 7.34 - 7.27 (m, 7 H), 6.93 - 6.80 (m, 4 H), 5.98 (d, J = 1.0 Hz, 1 H), 5.28 (dd, J = 2.0, 8.0 Hz, 1 H), 4.48 (dt, J = 5.4, 8.6 Hz, 1 H), 4.06 - 3.96 (m, 1 H), 3.81 (d, J = 0.6 Hz, 7 H), 3.66 (s, 3 H), 3.62 - 3.51 (m, 2 H)

[1345] LCMS (M-H+): 559.2, LCMS purity: 89%

[1346] TLC: Commercial hexanes: Ethyl acetate = 1:1, Rf = 0.13

[1347] 5. Preparation of compound 3:

[1348]

[1349] To a solution of compound 2 (60 g, 107.03 mmol) in DMF (600 mL) was added NaH (9.85 g, 246.17 mmol, 60% purity) at 0 °C under N2, the reaction was stirred at 0 °C for 0.5 h, then SEM-C1 (41.04 g, 246.17 mmol, 43.57 mL) was added, the reaction was stirred at 20°C for 1 h. TLC indicated compound 2 was consumed completely and one new spot formed. The reaction was poured into ice water (500 mL), extracted with Ethyl acetate (500 mL * 2), the combined extracts was dried over Na2SO4, filtered and concentrated. The residue was purified by column chromatography (SiCE, Commercial hexanes: Ethyl acetate = 1: 0 to 0: 1). Compound 3 (70 g, 67.70% yield) was obtained as a yellow oil.

[1350] ’H NMR (400 MHz, DMSO-d6) 6 = 7.87 (d, J = 8.0 Hz, 1 H), 7.39 - 7.30 (m, 4 H), 7.27 -7.21 (m, 5 H), 6.90 (d, J = 8.4 Hz, 4 H), 5.83 (d, J = 2.4 Hz, 1 H), 5.37 (d, J = 8.0 Hz, 1 H), 5.19 (s, 2 H), 4.72 - 4.64 (m, 2 H), 4.33 - 4.22 (m, 1 H), 4.10 (td, J = 3.2, 6.8 Hz, 1 H), 3.99 (dd, J = 2.6, 4.6 Hz, 1 H), 3.76 - 3.71 (m, 6 H), 3.62 - 3.46 (m, 5 H), 3.41 (s, 3 H), 3.40 -3.35 (m, 1 H), 0.88 - 0.81 (m, 4 H), -0.02 - -0.07 (m, 18 H)

[1351] TLC: Commercial hexanes: Ethyl acetate = 2:1, Rf = 0.63

[1352] 6. Preparation of compound 4:

[1353]

[1354] To a solution of compound 3 (70 g, 85.25 mmol) in MeOH (300 mL) was added a solution of AcOH (1.05 kg, 17.47 mol, 1000 mL) in H2O (250 mL), the reaction was stirred at 20 °C for 3 h. TLC indicated compound 3 was consumed completely and one new spot formed. The reaction was concentrated in vacuum. The residue was purified by column chromatography (SiO2, Commercial hexanes: Ethyl acetate = 1: 0 to 0: 1). Compound 4 (35 g, 71.23% yield) was obtained as yellow oil.

[1355] ’H NMR (400 MHz, DMSO-d6) 6 = 8.08 (d, J = 8.0 Hz, 1 H), 5.85 (d, J = 3.6 Hz, 1 H), 5.79 (d, J = 8.0 Hz, 1 H), 5.28 (t, J = 4.8 Hz, 1 H), 5.20 (s, 2 H), 4.69 (d, J = 0.8 Hz, 2 H), 4.17 - 4.11 (m, 1 H), 4.01 - 3.99 (m, 1 H), 3.91 (t, J = 4.2 Hz, 1 H), 3.77 - 3.69 (m, 1 H), 3.68 - 3.61 (m, 1 H), 3.60 - 3.51 (m, 4 H), 3.38 (s, 3 H), 0.93 - 0.77 (m, 4 H), -0.03 (d, J = 15.8 Hz, 18 H)

[1356] TLC: Commercial hexanes: Ethyl acetate = 1:1, Rf = 0.29

[1357] 7. Preparation of compound 5:

[1358]

[1359] A mixture of compound 4 (25 g, 48.19 mmol), TsCl (11.03 g, 57.83 mmol), DMAP (588.77 mg, 4.82 mmol) in Py. (300 mL) was degassed and purged with N2 for 3 times, and then the mixture was stirred at 20 °C for 12 h under N2 atmosphere. LCMS showed compound 4 was consumed completely and desired mass was detected. The reaction was added water (300 mL), extracted with Ethyl acetate (500 mL * 2), the combined extracts was dried over Na2SO4, filtered and concentrated. The residue was purified by column chromatography (SiO2, Commercial hexanes: Ethyl acetate =1:0 to 0:1). Compound 5 (18 g, 53.84% yield, 97% purity) was obtained as a white solid.

[1360] 'll NMR (400 MHz, CHLOROFORM-d) 8 = 7 80 (d, J = 8.2 Hz, 2 H), 754 (d, J = 8.2 Hz, 1 H), 7.39 (d, J = 8.2 Hz, 2 H), 5.92 - 5.82 (m, 1 H), 5.63 (d, J = 8.0 Hz, 1 H), 5.37 (q, J = 9.6 Hz, 2 H), 4.76 - 4.69 (m, 2 H), 4.48 - 4.24 (m, 3 H), 4.00 (dd, J = 4.8, 8.6 Hz, 1 H), 3.86 (d, J = 4.8 Hz, 1 H), 3.78 - 3.66 (m, 3 H), 3.64 - 3.53 (m, 4 H), 2.47 (s, 3 H), 1.05 -0.90 (m, 4 H), 0.01 (d, J = 7.8 Hz, 17 H)

[1361] LCMS (M+18): 690.2, LCMS purity: 97%

[1362] 8. Preparation of compound 6&6A:

[1363]

[1364] A mixture of compound 4A (3.89 g, 17.83 mmol), compound 5 (12 g, 17.83 mmol), CS2CO3 (17.43 g, 53.50 mmol) in DMF (100 mL) was stirred at 70 °C for 5 h. LCMS showed compound 5 was consumed completely and desired mass was detected. The reaction was filtered and added water (100 mL), extracted with Ethyl acetate (100 mL * 2), the combined extracts was dried over Na2SO4, filtered and concentrated. The residue was purified by column chromatography (SiO2, Ethyl acetate: Methanol = 1:0 to 5:1). Compound 6 & Compound 6A (7 g, 45% yield) was obtained as yellow oil.For seven batches: The residue (7 g) was purified by prep-HPLC (FA condition; column: Phenomenex luna Cl 8 100*40 mm*3 um; mobile phase: [H2O (0.2% FA)-ACN]; gradient: 30%-60% B over 15.0 min) to give compound 6 (3 g, 95% purity) as a yellow oil. Compound 6A (1 g, 94% purity) as a yellow oil.

[1365] Compound 6:

[1366] ’H NMR (400 MHz, CHLOROFORM-d) 8 = 8.14 (br s, 0.57 H), 7.58 (s, 1 H), 7.04 (br s, 1 H), 6.70 (d, J = 8.0 Hz, 1 H), 5.85 - 5.70 (m, 2 H), 5.43 - 5.31 (m, 2 H), 4.79 (s, 2 H), 4.40 - 4.17 (m, 3 H), 4.14 - 4.07 (m, 4 H), 3.88 - 3.63 (m, 6 H), 3.53 (s, 3 H), 3.26 - 3.12 (m, 2 H), 1.30 (t, J = 7.0 Hz, 6 H), 1.03 - 0.89 (m, 4 H), 0.10 - 0.05 (m, 18 H)

[1367] 31P NMR (162 MHz, CHLOROFORM-d) δ = 25.86 (s, 1P)

[1368] LCMS (M+H+): 719.2, purity: 95%

[1369] Compound 6A:

[1370] ’H NMR (400 MHz, CHLOROFORM-d) 8 = 8.36 - 8.00 (m, 0.38 H), 7.67 (s, 1 H), 6.99 (br d, J = 3.4 Hz, 1 H), 6.64 (d, J = 8.2 Hz, 1 H), 5.88 (s, 1 H), 5.69 (d, J = 8.2 Hz, 1 H), 5.41 - 5.31 (m, 2 H), 4.81 (s, 2 H), 4.71 - 4.58 (m, 1 H), 4.56 - 4.42 (m, 1 H), 4.38 - 4.27 (m, 1 H), 4.07 - 4.00 (m, 3 H), 3.82 - 3.79 (m, 1 H), 3.78 - 3.72 (m, 3 H), 3.71 - 3.66 (m, 3 H), 3.56 (s, 3 H), 3.26 - 3.16 (m, 2 H), 1.27 (q, J = 7.2 Hz, 6 H), 1.04 - 0.92 (m, 4 H), 0.02 (d, J = 14.8 Hz, 18 H)

[1371] 31P NMR (162 MHz, CHLOROFORM-d) δ = 23.22 (s, 1P)

[1372] LCMS (M+H+): 719.2, purity: 94%

[1373] 9. Preparation ofWV-NU-372:

[1374]

[1375] To a solution of compound 6 (2.9 g, 4.03 mmol) in DCM (30 mL) was added TFA (8.90 g, 78.08 mmol, 5.80 mL), the reaction was stirred at 20 °C for 12 h. LCMS showed compound 6 was consumed completely and desired mass was detected. The reaction was filtered and concentrated in vacuum. The residue was purified by prep-HPLC (basic condition; column:Welch Xtimate Cl 8250*100 mm# IO um; mobile phase: [H2O (0.1% TFA)-ACN]; gradient: 0%-25% B over 20.0 min). WV-NU-372 (1.5 g, 72% yield, 98% purity) was obtained as a white solid.

[1376] ’H NMR (400 MHz, DMSO-d6) 6 = 11.44 (d, J = 1.8 Hz, 1 H), 8.96 (s, 1 H), 7.70 (d, J = 8.0 Hz, 1 H), 7.49 (d, J = 2.2 Hz, 1 H), 5.79 (d, J = 4.8 Hz, 1 H), 5.67 (dd, J = 2.0, 8.0 Hz, 1 H), 4.61 - 4.52 (m, 1 H), 4.51 - 4.40 (m, 1 H), 4.15 - 4.08 (m, 2 H), 4.07 - 3.90 (m, 6 H), 3.44 - 3.34 (m, 5 H), 1.19 (dt, J = 5.0, 7.0 Hz, 6 H)

[1377] 31P NMR (162 MHz, DMSO-d6) δ = 22.59 (s, 1P)

[1378] LCMS (M+H+): 459.1, LCMS purity: 98%

[1379] / 0. Preparation of WV-NU-383:

[1380]

[1381] To a solution of compound 6A (1 g, 1.39 mmol) in DCM (10 mL) was added TFA (3.17 g, 27.82 mmol, 2.07 mL), the reaction was stirred at 20 °C for 12 h. LCMS showed compound 6A was consumed completely and desired mass was detected. The reaction was filtered and concentrated in vacuum. The residue was purified by prep-HPLC (basic condition; column: Phenomenex luna C18 250*50 mm*15 um; mobile phase: [H2O (0.1% TFA)-ACN]; gradient: l%-30% B over 10.0 min). WV-NU-383 (430 mg, 65.48% yield, 98% purity) was obtained as a white solid.

[1382] ’H NMR (400 MHz, DMSO-d6) 8 = 11.47 - 11.40 (m, 1 H), 9.05 (s, 1 H), 7.72 (d, J = 8.0 Hz, 1 H), 7.54 - 7.48 (m, 1 H), 5.75 (d, J = 4.2 Hz, 1 H), 5.64 (dd, J = 1.8, 8.0 Hz, 1 H), 4.69 - 4.60 (m, 1 H), 4.60 - 4.50 (m, 1 H), 4.16 - 3.94 (m, 7 H), 3.52 (s, 1 H), 3.47 (s, 1 H), 3.41 - 3.35 (m, 3 H), 1.21 (dt, J = 1.8, 7.0 Hz, 6 H)

[1383] 31P NMR (162 MHz, DMSO-d6) δ = 22.40 (s, 1P)

[1384] LCMS (M+H+): 459.1, purity: 98%

[1385] EXAMPLE 26. Synthesis of WV-NU-396A

[1386]

[1387] Experimental Procedure:

[1388] 1. Preparation of compound 2 •

[1389]

[1390] To a solution of compound 1 (33 g, 352.33 mmol) in THF (500 mL) was added dropwise n- BuLi (2.5 M, 140.93 mL) at -78 °C under N2. After addition, the mixture was stirred at this temperature for 10 min, and then 2,2,2-trifluoro- 1 -phenyl-ethanone (73.62 g, 422.80 mmol) was added dropwise at -78 °C, the mixture was stirred at this temperature for 10 min, 1- ethoxyphosphonoyloxyethane (72.99 g, 528.50 mmol) was added dropwise at -78 °C. The resulting mixture was stirred at 25°C for 12 h. TLC indicated no compound 1 remained, and one major new spot with larger polarity was detected. Each reaction mixture was added dropwise NH4Q 250 mL at 0 °C and then diluted with water 1500 mL and extracted with EtOAc (400 mL * 3). The combined organic layers were dried over Na2SO4, fdtered and concentrated under reduced pressure to give a residue. The residue was purified by flash silica gel chromatography (ISCO®; 330 g SepaFlash® Silica Flash Column, Eluent of 0~10% Dichloromethane: Methanol 150 mL / min). Compound 3A (2 25 g, 9.48% yield)was obtained as a yellow oil.

[1391] 'H NMR (400 MHz, CHLOROFORM-d) 5 = 4.08 (br s, 4H), 3.25 - 3.19 (m, 1H), 3.18 - 3.11 (m, 1H), 2.95 - 2.86 (m, 1H), 2.82 - 2.72 (m, 1H), 1.82 - 1.63 (m, 3H), 1.38 (br s, 5H), 1.30 - 1.25 (m, 6H), 1.11 - 0.88 (m, 3H)

[1392] TLC: Dichloromethane: Methanol = 10: 1, Rf = 0.23

[1393]

[1394] To a solution compound 2 (6 g, 25.50 mmol) in MeOH (400 mL) was added dropwise AcOH (1.53 g, 25.50 mmol, 1.46 mL) and Cpd.4 (9.45 g, 25.50 mmol) at 20 °C, then NaBH₃CN (2.40 g, 38.26 mmol) was added at 20 °C. The resulting mixture was stirred at 20 °C for 2 hr. LCMS showed compound 2 was consumed completely desired mass was detected. The reaction mixture was added dropwise H2O 200 mL at 0 °C, and then diluted with water 200 mL and extracted with EtOAc (200 mL * 3). The combined organic layers were dried over

[1395]

[1396] A mixture of compound 5 (0.8 g, 1.36 mmol)), N, N-diethylethanamine; trihydrofluoride (656.06 mg, 4.07 mmol) in THF (10 mL) was degassed and purged with N2 for 3 times, and then the mixture was stirred at 20 °C for 2h under N2 atmosphere. LCMS showed compound 5 was consumed completely desired mass was detected. The mixture was

[1397]

[1398]

[1399] ,Experimental Procedure:

[1400] 1. Preparation of compound 2C:

[1401]

[1402] 1C 2C

[1403] To a solution of compound 1C (18 g, 124.57 mmol) in THF (400 mL) was added bromo(ethynyl)magnesium (0.5 M, 249.15 mL) under N2. The mixture was stirred at 0 °C for 4 hr. TLC showed the product was detected. Each reaction mixture was quenched by addition NH4Q 100 mL at 0 °C, and then diluted with water 100 mL and extracted with EtOAc (100 mL * 3). The combined organic layers were dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO₂, Commercial hexanes: Ethyl acetate = 10:1 to 0:1). Compound 2C (3.5 g, 10.48% yield) was obtained as yellow oil.

[1404] TLC: Commercial hexanes: Ethyl acetate = 0:1, Rf = 0.33

[1405] 2. Preparation of Compound SA:

[1406]

[1407] To a solution of compound 2C (3.5 g, 26.11 mmol, 1 eq) in ACN (40 mL) was added 4A MS (2 g), POM-I (25.28 g, 104.42 mmol). The mixture was stirred at 80 °C for 15 hr. TLC showed the product was detected. The reaction mixture was filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO₂, Petroleum ether: Ethyl acetate= 50: 1 to 10: 1). Compound 5A (7 g, 80.21% yield) was obtained as yellow oil.

[1408] ’H NMR (400 MHz, CHLOROFORM-d) 5 = 5.74 (d, J = 1.4 Hz, 2H), 5.71 (d, J = 0.6 Hz, 2H), 3.00 (d, J = 14.1 Hz, 1H), 1.25 (s, 18H)

[1409] TLC: Commercial hexanes: Ethyl acetate = 3:1, product Rf = 0.73

[1410] 3. Preparation of Compound 2:

[1411]

[1412] For two batches: To a solution of compound 1 (90 g, 164.66 mmol) in EtOH (1200 mL) was added drop wised a solution of NaIO4 (52.83 g, 247.00 mmol, 13.69 mL) in H2O (600 mL). The solution was stirred for 2 h at 20 °C under N2. TLC showed the product was detected. The combined organic layers were without purification used for next step directly.

[1413] TLC: Commercial hexanes: Ethyl acetate=O:l, product Rf= 0.58

[1414] 4. Preparation of Compound 3:

[1415]

[1416] 2 3

[1417] For three batches: Compound 2 (59 g, 108.35 mmol) in EtOH (1200 mL) and H2O (600 mL) from ET26219-1278 was added NaBH4 (8.20 g, 216.69 mmol) in small portions at 0 °C. The mixture was stirred at 20 °C for 0.5 hr. TLC showed the product was detected. 3reactions were combined for workup. The crude product on notebook page ET26219-1271 was combined to ET26219-1279 for further workup. The mixture was filtered, and the filter cake was washed with EtOAc (1000 mL). The filtrates were combined to move most of solvents, and the mixture was extracted with EtOAc (2000 mL*2), the combined organic was washed with water (2000 mL) and brine (3000 mL), dried over MgSO4, concentrated under reduced pressure to give a residue. 3 reactions were combined purification. The crude product on notebook page ET26219-1271was combined to ET26219-1279 for further purification. The residue was purified by column chromatography (SiO₂, Commercial hexanes: Ethyl acetate=10 / 1 to 0 / 1). Compound 3 (110 g, crude) was obtained as a white solid.

[1418] TLC: Commercial hexanes: Ethyl acetate = 0:1, product Rf = 0.14

[1419] 5. Preparation of Compound 4:

[1420]

[1421] Compound 3 (110 g, 200.52 mmol) was co-evaporated with anhydrous Tol. (1000 mL) and dried in vacuo. The resulting residue was dissolved in anhydrous DCM (1000 mL) along with anhydrous Py (28.5 mL) and the mixture was cooled to -78 °C. BzCl (28.19 g, 200.52 mmol, 23.28 mL) was added to the mixture over 30 min and stirring was continued for 1 h at -78 °C. TLC showed the product was detected. The reaction mixture was filtered and the solution collected, then extracted with ethyl acetate 240 mL (80 mL x 3). The combined organic layers were washed with aqueous NaHCO₃ 200 mL (100 mL x 2), brine 200 mL (100 mL x 2), dried over Na₂SO₄, the organic phases were combined and evaporated to dryness under reduced pressure. The residue was purified by column chromatography (SiO₂, Commercial hexanes: Ethyl acetate = 10:1 to 0:1). Compound 4 (61 g, 46.61% yield) was obtained as a white solid.

[1422] ’H NMR (400 MHz, CHLOROFORM-d) 5 = 8.85 (br d, J = 11.2 Hz, 1H), 7.98 (d, J = 7.4 Hz, 2H), 7.61 - 7.54 (m, 1H), 7.49 - 7.41 (m, 3H), 7.34 (br d, J = 7.4 Hz, 2H), 7.28 - 7.18 (m, 8H), 6.80 (d, J = 8.8 Hz, 4H), 6.24 (t, J = 4.8 Hz, 1H), 5.62 (dd, J = 1.6, 8.0 Hz, 1H), 4.62 - 4.45 (m, 2H), 3.78 (s, 6H), 3.74 - 3.68 (m, 2H), 3.23 (br d, J = 4.6 Hz, 2H), 2.37 -2.29 (m, 1H)

[1423] TLC: Commercial hexanes: Ethyl acetate=O:l, product Rf= 0.446. Preparation of Compound 5:

[1424]

[1425] To a solution of compound 4 (55 g, 84.27 mmol) in DCM (800 mL) was added TBSC1 (15.24 g, 101.12 mmol, 12.44 mL) and imidazole (14.34 g, 210.67 mmol) at 20 °C. The solution was stirred at 20 °C for 3 h. LCMS showed the product was detected. The reaction mixture was added H2O 200 ml then extracted with EtOAc 1200 mL (400 mL * 3). The combined organic layers were washed with H2O 300 mL (100 mL * 3), dried over Na₂SO₄, filtered and concentrated under reduced pressure to give a residue. Without purification used for next step. Compound 5 (64 g, crude) was obtained as a white solid.

[1426] LCMS (M-H+): 765.4

[1427] 7. Preparation of Compound 6:

[1428]

[1429] To a solution of compound 5 (61 g, 79.54 mmol) in MeOH (800 mL) was added K2CO3 (21.99 g, 159.07 mmol) the reaction was stirred at 25 °C for 12h. LCMS showed the product was detected. The reaction mixture was filtered and, concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, Commercial hexanes: Ethyl acetate = 10: 1 to 0: 1). Compound 6 (42 g, 79.67% yield) was obtained as a white solid.

[1430] ’H NMR (400 MHz, DMSO-d6) 5 = 11.36 (s, 1H), 7.66 (d, J = 8.0 Hz, 1H), 7.34 - 7.24 (m, 4H), 7.22 - 7.13 (m, 5H), 6.85 (dd, J = 2.8, 9.0 Hz, 4H), 5.82 (t, J = 5.8 Hz, 1H), 5.53 (d, J = 8.0 Hz, 1H), 5.11 (t, J = 5.8 Hz, 1H), 3.72 (s, 6H), 3.66 - 3.58 (m, 4H), 3.54 - 3.46 (m, 1H), 3.02 - 2.92 (m, 2H), 0.75 (s, 9H), -0.04 (d, J = 8.4 Hz, 6H)

[1431] LCMS (M-H+): 661.4

[1432] TLC: Commercial hexanes: Ethyl acetate= 0:1, product Rf= 0.17

[1433] 8. Preparation of Compound 7:

[1434]

[1435] To a solution of compound 6 (25.5 g, 38.47 mmol) in THF (255 mL) was added NaH (4.62 g, 115.41 mmol, 60% purity) at 0 °C under N2, the reaction was stirred at 0 °C for 0.5 h then CH3I (8.19 g, 57.71 mmol, 3.59 mL) was added dropwise to the above reaction mixture, the reaction was stirred at 25 °C for 2 h. LCMS showed the product was detected. The mixture was added NH4CI 100 mL slowly drop by drop and stirred for 0.5 h at 0 °C under N2. The reaction mixture was allowed to warm to 20 °C, then the mixture was stirred for 0.5 h at 20 °C under N2, the aqueous phase was extracted with ethyl acetate (300 mL *3). Tertiary extraction of organic phase was Na2SO4, then combined organic phase was washed with brine (150 mL*2) and dried over Na2SO4, the combined organic concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO₂, Commercial hexanes: Ethyl acetate=10 / 1 to 0 / 1). Compound 7 (21.5 g, 82.57% yield) was obtained as colorless oil.

[1436] ’H NMR (400 MHz, DMSO-d6) 5 = 11.42 (s, 1H), 7.69 (d, J = 8.1 Hz, 1H), 7.34 - 7.24 (m, 4H), 7.23 - 7.14 (m, 5H), 6.85 (dd, J = 2.6, 9.0 Hz, 4H), 6.02 (t, J = 6.1 Hz, 1H), 5.56 (d, J = 8.0 Hz, 1H), 3.73 (s, 6H), 3.68 - 3.58 (m, 4H), 3.57 - 3.50 (m, 1H), 3.27 (s, 3H), 3.02 - 2.91 (m, 2H), 0.77 (s, 9H), -0.03 (d, J = 7.0 Hz, 6H)

[1437] LCMS (M-H+): 675.4

[1438] TLC: Commercial hexanes: Ethyl acetate= 2:1, product Rf= 0.59

[1439] 9. Preparation of Compound 8:

[1440]

[1441] 7 8

[1442] To a solution of compound 7 (21.5 g, 31.76 mmol) in DCM (215 mL) was added dodecane-1 -thiol (8.36 g, 41.29 mmol, 9.89 mL) at 25 °C. The solution was cooled to 0 °C and was dropwise added TFA (15.35 g, 134.63 mmol, 10.00 mL) at 0 °C. The solution was stirred at 0 °C for 1 h. LCMS showed the product was detected. The reaction mixture was diluted with DCM (100 mL). The combined organic layers were washed with H₂O (100 mL x 4), NaHCO3 (200 mL x 4), brine (100 ml x 2), dried over Na2SO4, filtered, and concentratedunder reduced pressure to give a residue. The crude product on notebook page ET26219-1305 was combined to ET26219-1305 for further purification. The combined crude product was purified by column chromatography (SiO₂, Commercial hexanes: Ethyl acetate=10 / 1 to 0 / 1). Compound 8 (15 g, crude) was obtained as a white solid.

[1443] ’H NMR (400 MHz, DMSO-d6) 5 = 11.26 (s, 1H), 7.63 (d, J = 8.0 Hz, 1H), 6.03 (t, J = 5.8 Hz, 1H), 5.60 (d, J = 8.0 Hz, 1H), 4.62 (t, J = 5.6 Hz, 1H), 3.73 - 3.67 (m, 1H), 3.63 - 3.57 (m, 1H), 3.57 - 3.49 (m, 2H), 3.48 - 3.41 (m, 1H), 3.30 - 3.27 (m, 1H), 3.25 (s, 3H), 0.88 (s, 9H), 0.06 (s, 6H)

[1444] LCMS (M-H+): 373.1

[1445] TLC: Commercial hexanes: Ethyl acetate= 0:1, product Rf= 0.2.

[1446] 10. Preparation of Compound 9:

[1447]

[1448] To a solution compound 8 (13 g, 34.71 mmol) in THF (130 mL) was added diimidazole (6.14 g, 90.25 mmol,), triphenylphosphine (14.57 g, 55.54 mmol) at 20 °C under N2. After addition, the mixture was stirred at this temperature for 0.5 h, and then I2 (14.10 g, 55.54 mmol, 11.19 mL) was added at 20 °C under N2. The resulting mixture was stirred at 20 °C for 12h. LCMS showed the product was detected. The reaction mixture was added H2O 200 ml then extracted with EtOAc 300 mL (100 mL * 3). The combined organic layers were washed with H2O 300 mL (100 mL * 3), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO₂, Commercial hexanes: Ethyl acetate = 10:1 to 0:1). Compound 9 (14.5 g, 86.23% yield) was obtained as a white gum.

[1449] ’H NMR (400 MHz, DMSO-d6) 5 = 11.34 (s, 1H), 7.68 (d, J = 8.0 Hz, 1H), 6.04 (dd, J = 5.4, 7.0 Hz, 1H), 5.66 (d, J = 8.0 Hz, 1H), 3.73 - 3.53 (m, 5H), 3.29 (dd, J = 4.0, 10.8 Hz, 1H), 3.25 (s, 3H), 3.19 - 3.09 (m, 1H), 0.88 (s, 9H), 0.08 (d, J = 2.4 Hz, 6H)

[1450] LCMS (M-H+): 483.1

[1451] TLC: Commercial hexanes: Ethyl acetate= 1:1, product Rf= 0.57

[1452] 11. Preparation of Compound 10:

[1453]

[1454] To a solution of compound 9 (9.4 g, 19.41 mmol) in DMF (90 mL) was added NaN₃ (1.13 g, 17.38 mmol) at 20 °C. After addition, the resulting mixture was stirred at 80 °C for 12 h. LCMS showed the product was detected. The mixture was added 4M NaOH to pH>12, then the mixture was diluted with H2O 100 mL and extracted with EtOAc (100 mL * 3). The combined organic layers were dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO2, Commercial hexanes: Ethyl acetate = 10:1 to 0:1). Compound 10 (6 g, 77.39% yield) was obtained as yellow oil.

[1455] 1H NMR (400 MHz, DMSO-d6) 5 = 11.34 (s, 1H), 7.64 (d, J = 8.0 Hz, 1H), 6.04 (t, J = 6.0 Hz, 1H), 5.66 (d, J = 8.0 Hz, 1H), 3.67 (s, 3H), 3.63 - 3.55 (m, 2H), 3.45 - 3.38 (m, 1H), 3.26 (s, 3H), 3.24 - 3.18 (m, 1H), 0.88 (s, 9H), 0.07 (s, 6H)

[1456] LCMS (M-H+): 398.2

[1457] TLC: Commercial hexanes: Ethyl acetate= 1:1, product Rf= 0.49

[1458] 12. Preparation of Compound 11:

[1459]

[1460] To a solution of compound 10 (7.5 g, 18.77 mmol) in THF (20 mL) was added TEA.3HF (12.11 g, 75.09 mmol, 12.24 mL) the reaction was stirred at 40 °C for 2 h. LCMS showed the product was detected. Concentrated under reduced pressure to give a residue. The residue was purified by column chromatography (SiO₂, Commercial hexanes: Ethyl acetate = 10:1 to 0:1). Compound 11 (5.2 g, 97.11% yield) was obtained as yellow oil.

[1461] ’H NMR (400 MHz, CHLOROFORM-d) 5 = 9.18 (br s, 1H), 7.49 (d, J = 8.0 Hz, 1H), 6.12 (dd, J = 4.6, 6.8 Hz, 1H), 5.82 (dd, J= 1.6, 8.0 Hz, 1H), 3.84 - 3.74 (m, 2H), 3.70 - 3.55 (m, 3H), 3.44 (s, 3H), 3.40 - 3.35 (m, 2H), 3.07 - 2.95 (m, 1H)

[1462] LCMS (M-H+): 284.0

[1463] TLC: Ethyl acetate: Methanol= 10:1, product Rf= 0.4213. Preparation ofWV-NU-444:

[1464]

[1465] WV-NU-444

[1466] To a solution of compound 11(5.2 g, 18.23 mmol) compound 5A (7.31 g, 21.88 mmol) in THF (100 mL) was added Cui (6.94 g, 36.46 mmol) DIEA (4.71 g, 36.46 mmol, 6.35 mL). The mixture was stirred at 25 °C for 1.5 hr. LCMS showed the product was detected. The reaction mixture was added H2O 50 ml then extracted with EtOAc 150 mL (50 mL * 3). The combined organic layers were washed with H2O 120 mL (40 mL * 3), dried over Na2SO4, filtered and concentrated under reduced pressure to give a residue. The crude product on notebook page ET26219-1337 was combined to ET26219-1340 further purification. The residue was purified by column chromatography (SiCL, Commercial hexanes: Ethyl acetate=10 / l to 0 / 1). WV -NU-444 (7.54 g, 63.36% yield, 94.91% purity) was obtained as a yellow solid.

[1467] ’H NMR (400 MHz, DMSO-d6) 5 = 11.22 (d, J = 1.8 Hz, 1H), 8.66 (s, 1H), 6.96 (d, J = 8.0 Hz, 1H), 5.96 (dd, J = 5.2, 6.8 Hz, 1H), 5.74 - 5.63 (m, 4H), 5.35 (dd, J = 2.0, 8.0 Hz, 1H), 5.11 (t, J = 5.4 Hz, 1H), 4.57 - 4.47 (m, 2H), 3.97 - 3.84 (m, 1H), 3.66 - 3.45 (m, 4H), 3.22 (s, 3H), 1.12 (d, J = 4.8 Hz, 18H)

[1468] LCMS (M-H+): 618.2, purity: 94.91%

[1469] TLC: Ethyl acetate: Methanol = 10:1, product Rf = 0.46

[1470] EXAMPLE 28. Synthesis of 5’-Triazolylphosphonate L-PSM and D-PSM Amidites General Procedure:

[1471] Nucleosides (1.0 eq.) in an appropriate size three necked flask was azeotroped with anhydrous toluene (15 mL / g) and anhydrous acetonitrile (15 mL / g) and was dried for 24 hours on high vacuum. To the flask was added anhydrous THF (0.2 M solution) under argon and solution was cooled to 0°C. To the reaction mixture was added triethyl amine (2.2 eq.)followed by addition of L-PSM-C1 or D-PSM-C1 (0.86-0.94 M) solution (1.6 eq.) over the period of 5-10 min. The reaction mixture was warmed to room temperature and reaction progress was monitored by HPLC. After disappearance of starting material, the reaction mixture was filtered through fritted glass tube. Reaction flask and precipitate was washed with anhydrous THF. Obtained filtrate was collected and solvent was removed under reduced pressure. The residue was purified by column chromatography (SiO2, 40-80% Ethyl acetate in Hexanes with 1.25% tri ethyl amine and 20-100% Acetonitrile in Ethyl acetate with 1.25% tri ethyl amine) to give to give 5’-Triazolyl-Phosphonate amidite as off-white solid.

[1472] Synthesis of 2’-OMe- 5’-PO(OEt)2 Triazolyl Phosphonate Uridine L-PSM amidite.

[1473]

[1474] 2’-OMe- 5’-PO(OEt)2 Triazolyl Phosphonate Uridine L-PSM amidite.

[1475] Nucleoside 2’-OMe- 5’-PO(OEt)2 Triazolyl Phosphonate Uridine (WV-NU-306, 4.5 g) was converted to 2’-OMe- 5’-PO(OEt)2 Triazolyl Phosphonate Uridine L-PSM amidite.

[1476] (5.39 g, 74.0% yield) as an off-white solid.

[1477] LCMS: C28H38N6O11P2S (M-H-): 727.34

[1478] 'H NMR (600 MHz, CDCI3) 59.05 (s, 1H), 8.22 (s, 1H), 7.97 - 7.93 (m, 2H), 7.69 - 7.62 (m, 1H), 7.58 (ddt, J = 8.0, 6.7, 1.2 Hz, 2H), 6.95 (d, J = 8.1 Hz, 1H), 5.71 (d, J = 8.1 Hz, 1H), 5.54 (d, J = 3.5 Hz, 1H), 5.24 (ddd, J = 8.2, 5.9, 4.1 Hz, 1H), 4.86 -4.74 (m, 2H), 4.54 - 4.49 (m, 1H), 4.35 (td, J = 6.2, 3.3 Hz, 1H), 4.29 - 4.14 (m, 4H), 4.03 (dd, J = 5.7, 3.5 Hz, 1H), 3.78 - 3.72 (m, 1H), 3.61 -3.51 (m, 2H), 3.48 (s, 3H), 3.42 - 3.36 (m, 1H), 3.26 (tdd, J = 10.4, 8.8, 4.1 Hz, 1H), 1.96- 1.79 (m, 2H), 1.67 - 1.61 (m, 1H), 1.34 (tdd, J = 7.1, 6.1, 0.5 Hz, 6H), 1.14 (dtd, J = 11.7, 10.2, 8.6 Hz, 1H).

[1479] 31P NMR (243 MHz, CDCI3) 5 154.80, 6.76.13C NMR (151 MHz, CDC13) 6 162.58, 149.78, 141.65, 139.80, 134.25, 132.61, 132.39, 129.60, 128.19, 103.23, 92.76, 81.27, 81.25, 80.71, 80.69, 74.53, 74.46, 70.89, 70.81, 66.49, 66.47, 63.28, 63.26, 63.24, 63.22, 59.18, 58.10, 58.07, 50.39, 46.66, 46.43, 27.44, 26.18, 26.15, 16.47, 16.42.

[1480] Synthesis of 2’-OMe- 5’-PO(POM)i Triazolyl Phosphonate Uridine L-PSM amidite.

[1481]

[1482] Nucleoside 2’-OMe- 5’-PO(POM)i Triazolyl Phosphonate Uridine (WV-NU-332, 2.26 g) was converted to 2’-OMe- 5’-PO(POM)i Triazolyl Phosphonate Uridine -L-PSM-amidite (2.03 g, 61.9% yield) as an off-white solid.

[1483] LCMS: C36H5ON6OI5P2S (M-H): 899.27

[1484] ’H NMR (600 MHz, CDCI3) 88.71 (s, 1H), 8.19 (s, 1H), 7.98 - 7.95 (m, 2H), 7.68 - 7.64 (m, 1H), 7.60 - 7.56 (m, 2H), 7.02 (d, J = 8.1 Hz, 1H), 5.82 - 5.76 (m, 4H), 5.73 (d, J = 8.0 Hz, 1H), 5.42 (d, J = 3.3 Hz, 1H), 5.24 (ddd, J = 8.2, 5.9, 4.1 Hz, 1H), 4.79 (qd, J = 14.8, 4.2 Hz, 2H), 4.51 (ddd, J = 9.3, 7.0, 5.9 Hz, 1H), 4.29 (ddd, J = 7.0, 4.9, 3.3 Hz, 1H), 4.06 (dd, J = 5.9, 3.3 Hz, 1H), 3.74 (dq, J = 9.8, 6.0 Hz, 1H), 3.61 - 3.51 (m, 2H), 3.48 (s, 3H), 3.39 (dd, J = 14.5, 4.1 Hz, 1H), 3.28 (tdd, J = 10.2, 8.7, 4.2 Hz, 1H), 1.96 - 1.81 (m, 2H), 1.66 (q, J = 6.7 Hz, 1H), 1.18 (d, J = 5.3 Hz, 18H).

[1485] 31P NMR (243 MHz, CDCI3) δ 153.73, 6.16

[1486] 13C NMR (151 MHz, CDCI3) 6 162.62, 149.72, 142.32, 139.89, 134.25, 133.01, 132.77, 129.60, 128.23, 103.34, 93.99, 82.29, 82.27, 82.24, 81.23, 81.21, 80.43, 74.73, 74.66, 70.49, 70.43, 66.51, 66.49, 59.32, 58.19, 58.16, 50.05, 46.62, 46.39, 38.89, 27.50, 26.96, 26.94, 26.22, 26.20.

[1487] Synthesis of 2’-OMe- 5’-PO(OCNE)i Triazolyl Phosphonate Uridine L-PSM amidite

[1488]

[1489] Nucleoside 2’-OMe- 5’-PO(OCNE)i Triazolyl Phosphonate Uridine

[1490] (WV-NU-336, 2.56 g) was converted to 2’-OMe- 5’-PO(OCNE)i Triazolyl Phosphonate Uridine L-PSM amidite (1.99 g, 50.4% yield) as an off-white solid.

[1491] LCMS: C30H36N8O11P2S (M-H): 777.29

[1492] ’H NMR (600 MHz, CDCI3) 89.04 (s, 1H), 8.42 (s, 1H), 7.98 - 7.93 (m, 2H), 7.70 - 7.65 (m, 1H), 7.59 (t, J = 7.8 Hz, 2H), 7.07 (d, J = 8.1 Hz, 1H), 5.71 (d, J = 8.0 Hz, 1H), 5.38 (d, J = 3.1 Hz, 1H), 5.26 (ddd, J = 8.2, 5.8, 4.1 Hz, 1H), 4.85 (qd, J = 14.8, 4.2 Hz, 2H), 4.50 -4.39 (m, 5H), 4.34 (ddd, J = 7.4, 5.0, 3.3 Hz, 1H), 4.17 (dd, J = 5.8, 3.2 Hz, 1H), 3.76 - 3.69 (m, 1H), 3.57 (dddd, J = 33.6, 15.3, 9.3, 5.1 Hz, 2H), 3.49 (s, 3H), 3.41 (dd, J = 14.4, 4.0 Hz, 1H), 3.33 - 3.26 (m, 1H), 2.88 - 2.77 (m, 4H), 1.97 - 1.82 (m, 2H), 1.68 - 1.61 (m, 1H), 1.20 - 1.10 (m, 1H).

[1493] 31P NMR (243 MHz, CDCI3) δ 154.25, 8.01

[1494] 13C NMR (151 MHz, CDCI3) 6 163.07, 149.81, 142.90, 139.87, 134.31, 133.56, 133.33, 129.65, 128.20, 116.84, 116.76, 103.11, 94.59, 81.01, 80.99, 80.36, 74.58, 74.51, 70.48, 70.41, 66.58, 66.56, 61.83, 61.80, 61.69, 61.66, 59.34, 58.12, 58.10, 50.01, 46.66, 46.42, 27.51, 26.21, 26.19, 20.04, 20.03, 20.00, 19.98, 14.37.

[1495] Synthesis of 2'-OMe-5'-PO(OEt)2-l,5-Triazolyl Phosphonate Uridine -L-PSM amidite.

[1496]

[1497] Nucleoside 2'-OMe-5'-PO(OEt)2-l,5-Triazolyl Phosphonate Uridine (WV-NU-343, 809 mg) was converted to 2'-OMe-5'-PO(OEt)2-l,5-Triazolyl Phosphonate Uridine -L-PSM amidite (945 mg, 76.6% yield) as an off-white solid.

[1498] LCMS: C28H38N6O11P2S (M-H): 727.34

[1499] ’H NMR (600 MHz, CDCI3) 88.64 (s, 1H), 7.99 (s, 1H), 7.97 - 7.92 (m, 2H), 7.68 - 7.63 (m, 1H), 7.58 (dd, J = 8.4, 7.2 Hz, 2H), 7.11 (d, J = 8.1 Hz, 1H), 5.76 (d, J = 3.9 Hz, 1H), 5.70 (d, J = 8.1 Hz, 1H), 5.15 (dt, J = 7.4, 5.4 Hz, 1H), 5.06 (dd, J = 14.4, 4.8 Hz, 1H), 4.93 (dd, J= 14.4, 6.1 Hz, 1H), 4.60 (dt, J = 9.1, 5.7 Hz, 1H), 4.53 (td, J = 6.1, 4.7 Hz, 1H), 4.26 -4.01 (m, 4H), 3.72 (dq, J= 11.5, 6.0, 5.1 Hz, 1H), 3.55 (td, J= 14.9, 7.3 Hz, 2H), 3.49 (s, 3H), 3.39 (dd, J = 14.5, 5.0 Hz, 1H), 3.22 (tdd, J = 10.3, 8.9, 4.1 Hz, 1H), 1.95 - 1.76 (m, 2H), 1.70 - 1.62 (m, 1H), 1.32 (td, J = 7.0, 5.7 Hz, 6H), 1.13 (dtd, J = 11.6, 10.1, 8.4 Hz, 1H).

[1500] 31P NMR (243 MHz, CDCI3) δ 154.40, 3.14

[1501] 13C NMR (151 MHz, CDCI3) 6 162.80, 149.87, 140.81, 140.35, 140.21, 139.69, 134.22, 129.55, 128.31, 102.83, 90.12, 81.49, 81.47, 81.26, 81.24, 74.84, 74.78, 71.51, 71.44, 66.38, 66.36, 63.90, 63.87, 58.90, 58.89, 58.14, 50.33, 46.61, 46.38, 27.51, 26.14, 16.40, 16.36, 16.32.

[1502] Synthesis of 2'-OMe-5'-(3-PO(OEt)2-pyrrolidinyl) phosphonate Uridine L-PSM amidite.

[1503]

[1504] Nucleoside 2'-OMe-5'-(3-PO(OEt)2-pyrrolidinyl) phosphonate Uridine (WV-NU-362, 5.01 g) was converted to 2'-OMe-5'-(3-PO(OEt)2-pyrrolidinyl) phosphonate Uridine L-PSM amidite. (4.80 g, 66.4% yield) as an off-white solid.

[1505] *H NMR (600 MHz, CDCh) 69.17 (s, 1H), 7.93 (dt, J = 7.2, 1.2 Hz, 2H), 7.67 (dd, J = 8.1, 6.7 Hz, 1H), 7.59 - 7.55 (m, 2H), 5.80 (dd, J = 26.8, 2.5 Hz, 1H), 5.73 (dd, J = 16.2, 8.1 Hz, 1H), 5.13 (q, J = 6.6, 6.1 Hz, 1H), 4.35 - 4.26 (m, 1H), 4.15 - 4.04 (m, 5H), 3.89 (dd, J = 5.5, 2.6 Hz, 1H), 3.70 (dp, J = 11.1, 5.7 Hz, 1H), 3.57 - 3.46 (m, 5H), 3.41 - 3.34 (m, 1H), 3.22 (qd, J = 10.0, 4.0 Hz, 1H), 3.06 (dq, J = 14.1, 8.9 Hz, 1H), 2.98 - 2.74 (m, 3H), 2.74 -2.64 (m, 1H), 2.59 (q, J = 8.0 Hz, 1H), 2.54-2.42 (m, 2H), 2.11 - 1.97 (m, 2H), 1.94- 1.75 (m, 2H), 1.66 - 1.59 (m, 1H), 1.29 (qd, J = 6.2, 5.4, 2.7 Hz, 6H), 1.16 - 1.07 (m, 1H).

[1506] 31PNMR(243 MHz, CDCh) 6 155.11 (d, J = 2.1 Hz), 32.29.

[1507] 13C NMR (151 MHz, CDCh) 6 163.31, 150.08, 141.02, 140.94, 139.71, 134.23, 129.54, 128.25, 102.69, 102.56, 89.95, 89.72, 82.64, 82.33, 81.58, 74.30, 71.75, 66.34, 61.97, 58.84, 56.14, 55.71, 55.29, 53.58, 46.73, 46.49, 33.40, 27.44, 26.14, 25.57.

[1508] Synthesis of 2'-OMe-5'-(3-PO(OEt)2-pyrrolidinyl) phosphonate Uridine D-PSM amidite.

[1509]

[1510] Nucleoside 2'-OMe-5'-(3-PO(OEt)2-pyrrolidinyl) phosphonate Uridine (WV-NU-362, 1.02 g) was converted to2'-OMe-5'-(3-PO(OEt)2-pyrrolidinyl) phosphonate Uridine D-PSM-amidite by general procedure (993 mg, 67.5% yield) as an off-white solid.

[1511] ’H NMR (600 MHz, CDCI3) 69.21 (s, 1H), 7.92 (d, J = 7.8 Hz, 2H), 7.67 (qd, J = 7.8, 1.4 Hz, 2H), 7.63 - 7.53 (m, 3H), 5.81 (dt, J = 19.4, 1.8 Hz, 1H), 5.73 (ddd, J = 14.9, 8.1, 1.4 Hz, 1H), 5.16 (q, J = 6.3 Hz, 1H), 4.29 - 4.19 (m, 1H), 4.11 (tt, J = 14.6, 6.5 Hz, 5H), 3.81 - 3.71 (m, 2H), 3.57 - 3.48 (m, 2H), 3.45 - 3.36 (m, 4H), 3.23 (tp, J = 9.6, 4.4 Hz, 1H), 3.09 (dq, J = 18.4, 8.8 Hz, 1H), 2.99 - 2.76 (m, 3H), 2.67 (tt, J = 16.9, 9.1 Hz, 1H), 2.58 (q, J = 8.0 Hz, 1H), 2.54 - 2.42 (m, 2H), 2.12 - 1.97 (m, 2H), 1.93 - 1.75 (m, 2H), 1.68 (dd, J = 12.2, 6.2 Hz, 1H), 1.30 (tdd, J = 7.0, 4.1, 2.1 Hz, 6H), 1.12 (p, J = 10.3 Hz, 1H).

[1512] 31P NMR (243 MHz, CDCI3) 8 155.44, 155.21, 32.22.

[1513] 13C NMR (151 MHz, CDCI3) 6 163.32, 163.30, 150.02, 140.86, 140.75, 139.68, 134.27, 129.59, 128.26, 102.59, 102.49, 89.51, 89.31, 83.11, 82.88, 81.25, 74.18, 74.12, 74.10, 74.04, 71.71, 71.63, 71.56, 66.30, 62.06, 62.04, 62.02, 62.00, 61.95, 61.90, 58.53, 58.49, 58.25, 58.23, 55.98, 55.83, 55.71, 55.57, 55.35, 55.06, 55.01, 46.82, 46.79, 46.59, 46.57, 34.39, 33.40, 27.56, 26.12, 26.10, 25.61, 25.57, 25.54, 16.77, 16.73, 16.72, 16.69, 16.68.

[1514] Synthesis of 2'-OMe-5'-(2-PO(OEt)2-pyrrolidinyl) phosphonate Uridine L-PSM amidite.

[1515]

[1516] 2'-OMe-5'-(2-PO(OEt)2-pyrrolidinyl)

[1517] phosphonate Uridine L-PSM amidite

[1518] Nucleoside 2'-OMe-5'-(2-PO(OEt)2-pyrrolidinyl) phosphonate Uridine (WV-NU-342, 4.83 g) was converted to 2'-OMe-5'-(2-PO(OEt)2-pyrrolidinyl) phosphonate Uridine L-PSM amidite (5.54 g, 72.9% yield) as an off-white solid.

[1519] ’H NMR (600 MHz, CDC13) 8 9.08 (s, 1H), 7.93 (ddd, J = 8.5, 3.2, 1.3 Hz, 2H), 7.69 -7.62 (m, 1H), 7.60 - 7.51 (m, 3H), 5.94 (dd, J = 27.7, 4.4 Hz, 1H), 5.79 (dd, J = 43.0, 8.1 Hz, 1H), 5.12 (tt, J = 7.3, 5.3 Hz, 1H), 4.64 (dt, J = 8.7, 4.2 Hz, 1H), 4.26 - 4.01 (m, 6H), 3.99 (t, J = 5.3 Hz, 1H), 3.67 (ttd, J = 8.5, 5.7, 2.4 Hz, 1H), 3.56 - 3.46 (m, 4H), 3.44 (s, 2H), 3.38 (ddd, J = 14.5, 6.7, 4.8 Hz, 1H), 3.32 - 3.17 (m, 3H), 3.03 - 2.87 (m, 1H), 2.81 -2.69 (m, 1H), 2.42 - 2.25 (m, 1H), 2.09 - 1.96 (m, 3H), 1.92 - 1.72 (m, 4H), 1.63 - 1.56 (m, 1H), 1.34 - 1.22 (m, 7H), 1.11 (dtd, J = 11.6, 10.0, 8.3 Hz, 1H).

[1520] 31PNMR(243 MHz, CDCI3) 6 157.18, 156.01, 26.37, 26.27.

[1521] 13C NMR (151 MHz, CDCI3) 6 163.22, 150.42, 150.40, 140.95, 140.50, 139.70, 139.57, 134.20, 129.57, 129.53, 128.28, 128.26, 102.92, 102.50, 88.53, 87.89, 82.77, 82.60, 82.58, 81.05, 81.02, 80.87, 80.84, 74.12, 74.05, 73.99, 73.93, 72.88, 72.79, 72.02, 71.92, 66.30, 66.27, 66.17, 66.14, 63.54, 63.23, 61.64, 61.59, 61.56, 61.51, 61.24, 60.78, 60.52, 60.09, 59.63, 58.82, 58.72, 58.35, 58.33, 58.15, 58.13, 57.63, 57.61, 55.15, 55.05, 54.81, 54.70, 46.85, 46.74, 46.61, 46.50, 27.40, 27.36, 26.78, 26.76, 26.73, 26.19, 26.17, 26.15, 26.12, 25.23, 25.19, 16.89, 16.86, 16.82, 16.79, 16.71, 16.67, 14.33.

[1522] Synthesis of 2'-OMe-5'-PO(OEt)2-Aziridinyl Phosphonate Uridine L-PSM amidite.

[1523]

[1524] Nucleoside 2'-OMe-5'-PO(OEt)2-Aziridinyl Phosphonate Uridine (WV-NU-365, 4.91 g) was converted to 2'-OMe-5'-PO(OEt)2-Aziridinyl Phosphonate Uridine L-PSM amidite (6.28 g, 78.4% yield) as an off-white solid.

[1525] ’H NMR (600 MHz, CDCh) 89.40 (s, 1H), 7.91 (ddt, J = 8.5, 4.9, 1.7 Hz, 2H), 7.68 - 7.63 (m, 1H), 7.56 (t, J = 7.8 Hz, 2H), 5.94 (dd, J = 20.5, 3.1 Hz, 1H), 5.74 (dd, J = 39.5, 8.1 Hz, 1H), 5.12 (dq, J = 7.4, 4.5 Hz, 1H), 4.14 - 4.02 (m, 5H), 3.96 (dd, J = 5.3, 3.6 Hz, 1H), 3.70 - 3.60 (m, 1H), 3.55 - 3.46 (m, 5H), 3.36 (dt, J = 14.5, 4.8 Hz, 1H), 3.22 (tddd, J = 10.1, 8.5, 3.8, 2.2 Hz, 1H), 3.10 - 3.00 (m, 1H), 2.44 (td, J = 13.4, 3.2 Hz, 1H), 2.19 - 2.10 (m, 1H), 1.92 - 1.66 (m, 4H), 1.57 (pd, J = 6.5, 5.8, 2.6 Hz, 1H), 1.32 - 1.25 (m, 6H), 1.14 -1.01 (m, 1H).

[1526] 31PNMR(243 MHz, CDCh) 6 157.51, 156.80, 22.61, 22.31.

[1527] 13C NMR (151 MHz, CDCh) 6 163.63, 163.59, 150.59, 150.37, 141.62, 141.22, 139.65, 134.21, 134.17, 129.54, 128.12, 128.08, 102.61, 102.49, 88.35, 87.80, 83.04, 82.44, 82.42, 81.90, 81.88, 73.77, 73.71, 73.62, 73.56, 70.45, 70.35, 70.15, 70.05, 66.29, 66.27, 66.25, 62.65, 62.61, 62.52, 62.50, 62.48, 62.44, 62.40, 59.96, 59.92, 59.79, 59.74, 58.69, 58.64, 57.91, 57.89, 46.75, 46.52, 33.92, 33.53, 33.49, 32.50, 31.72, 31.68, 31.54, 30.11, 27.27, 27.26, 26.10, 26.07, 26.04, 16.64, 16.62, 16.58, 1.97.

[1528] Synthesis of 2'-OMe-5'-PS(OEt)2-Triazolyl Thiophosphonate Uridine L-PSM amidite.

[1529]

[1530] 2'-OMe-5'-PS(OEt)2-Triazolyl Thiophosphonate Uridine L-PSM amidite. Nucleoside 2'-OMe-5'-PS(OEt)2-Triazolyl Thiophosphonate Uridine (WV-NU-350, 5.24 g) was converted to 2'-OMe-5'-PS(OEt)2-Triazolyl Thiophosphonate Uridine L-PSM amidite (6.53 g, 78.4% yield) as an off-white solid.

[1531] LCMS: C28H38N6O10P2S2 (M-H): 743.08

[1532] ’H NMR (600 MHz, CDCI3) 89.04 (s, 1H), 8.13 (s, 1H), 7.98 - 7.92 (m, 2H), 7.68 - 7.62 (m, 1H), 7.58 (t, J = 7.8 Hz, 2H), 6.87 (d, J = 8.1 Hz, 1H), 5.74 (d, J = 8.1 Hz, 1H), 5.62 (d, J = 3.8 Hz, 1H), 5.23 (ddd, J = 8.4, 5.8, 4.0 Hz, 1H), 4.78 (dd, J = 4.4, 2.6 Hz, 2H), 4.52 (dt, J = 9.2, 6.0 Hz, 1H), 4.36 (dt, J = 6.2, 4.5 Hz, 1H), 4.22 (ddddd, J = 20.1, 17.1, 10.0, 7.1, 3.0 Hz, 4H), 3.90 (dd, J = 5.7, 3.8 Hz, 1H), 3.75 (dq, J = 10.2, 6.0 Hz, 1H), 3.56 (ddt, J = 19.4, 14.5, 8.0 Hz, 2H), 3.47 (s, 3H), 3.40 (dd, J = 14.5, 4.0 Hz, 1H), 3.30 - 3.21 (m, 1H), 1.95 - 1.78 (m, 2H), 1.64 (dt, J = 12.2, 7.4 Hz, 1H), 1.33 (dt, J = 8.9, 7.1 Hz, 6H), 1.17 -1.09 (m, 1H).

[1533] 31P NMR (243 MHz, CDCI3) 6 154.80, 68.72.

[1534] 13C NMR (151 MHz, CDCI3) 6 162.91, 150.02, 141.26, 139.79, 134.25, 132.59, 132.35, 129.60, 128.19, 103.40, 91.78, 81.21, 81.19, 80.75, 80.73, 74.59, 74.53, 70.76, 70.69, 66.49, 66.46, 63.62, 63.60, 63.59, 63.56, 59.12, 59.10, 58.09, 58.07, 50.41, 46.68, 46.44, 27.44, 26.17, 26.14, 16.31, 16.29, 16.26, 16.24.

[1535] Synthesis of 2'-OMe-5'-PS(OEt)2-Triazolyl Thiophosphonate Uridine D-PSM amidite.

[1536]

[1537] 2'-OMe-5,-PS(OEt)2-Triazolyl

[1538] Thiophosphonate Uridine D-PSM amidite

[1539] Nucleoside 2'-OMe-5'-PS(OEt)2-Triazolyl Thiophosphonate Uridine (WV-NU-350, 1.02 g) was converted to 2'-OMe-5'-PS(OEt)2-Triazolyl Thiophosphonate Uridine D-PSM amidite.(1.83 g, 85.1% yield) as an off-white solid.

[1540] LCMS: C28H38N6O10P2S2 (M-H-): 743.17

[1541] ’H NMR (600 MHz, CDCI3) 89.12 (s, 1H), 8.07 (d, J = 2.6 Hz, 1H), 7.94 (d, J = 7.7 Hz, 2H), 7.67 (t, J = 7.6 Hz, 1H), 7.58 (t, J = 8.1 Hz, 2H), 6.87 (dd, J = 8.3, 2.4 Hz, 1H), 5.75 (dd, J = 8.0, 2.6 Hz, 1H), 5.61 (d, J = 3.8 Hz, 1H), 5.23 (t, J = 6.6 Hz, 1H), 4.82 - 4.68 (m, 2H), 4.51 (q, J = 7.4, 6.5 Hz, 1H), 4.40 (t, J = 4.9 Hz, 1H), 4.22 (qd, J = 14.8, 12.2, 5.7 Hz, 4H), 3.91 (q, J = 4.0 Hz, 1H), 3.77 (h, J = 7.1, 6.4 Hz, 1H), 3.62 - 3.46 (m, 2H), 3.41 (d, J = 2.9 Hz, 4H), 3.23 (dq, J = 15.2, 9.7, 7.8 Hz, 1H), 1.94- 1.77 (m, 2H), 1.71 - 1.62 (m, 1H), 1.34 (q, J = 8.8 Hz, 6H), 1.14 (p, J = 10.1 Hz, 1H).

[1542] 31P NMR (243 MHz, CDCI3) δ 154.47, 68.53

[1543] 13C NMR (151 MHz, CDCI3) 6 162.97, 150.03, 141.46, 139.76, 134.27, 132.41, 132.17, 129.57, 128.31, 103.41, 91.89, 81.11, 80.81, 80.78, 74.72, 74.65, 70.85, 70.79, 66.33, 66.31, 63.64, 63.60, 58.78, 58.29, 58.26, 50.62, 46.78, 46.55, 27.58, 26.17, 16.32, 16.29, 16.27, 16.25.

[1544] Synthesis of 2'-OMe-5'-PO(OEt)2-Triazolyl methyl phosphonate Uridine L-PSM amidite.

[1545]

[1546] 2'-OMe-5'-PO(OEt)2-Triazolyl methyl phosphonate Uridine L-PSM amidite. Nucleoside 2'-OMe-5'-PO(OEt)2-Triazolyl methyl phosphonate Uridine (WV-NU-352, 3.03 g) was converted to 2'-OMe-5'-PO(OEt)2-Triazolyl methyl phosphonate Uridine L-PSM amidite (3.47 g, 72.5% yield) as an off-white solid.

[1547] LCMS: C28H38N6O11P2S (M-H): 727.06

[1548] ’H NMR (600 MHz, CDCI3) 89.49 (s, 1H), 8.14 (d, J = 8.1 Hz, 1H), 7.98 (s, 1H), 7.84 (d, J = 7.7 Hz, 2H), 7.64 (t, J = 7.5 Hz, 1H), 7.54 (t, J = 7.6 Hz, 2H), 6.17 (d, J = 4.5 Hz, 1H), 5.76 (d, J = 8.1 Hz, 1H), 5.27 (d, J = 4.7 Hz, 1H), 5.12 - 5.06 (m, 1H), 4.89 - 4.73 (m, 2H), 4.67 (dt, J = 9.0, 4.6 Hz, 1H), 4.28 (t, J = 4.6 Hz, 1H), 4.18 - 4.04 (m, 4H), 3.61 (dq, J = 11.8, 6.0 Hz, 1H), 3.50 (s, 3H), 3.43 (ddd, J = 18.6, 14.5, 9.3 Hz, 2H), 3.32 (dd, J = 14.6, 3.6 Hz, 1H), 3.19 (qd, J = 9.8, 3.8 Hz, 1H), 1.87 - 1.69 (m, 2H), 1.55 - 1.48 (m, 1H), 1.25 (dt, J = 11.3, 7.1 Hz, 6H), 1.05 (h, J = 10.2 Hz, 1H).

[1549] 31P NMR (243 MHz, CDCl3) δ 157.43, 15.71

[1550] 13C NMR (151 MHz, CDCI3) 6 163.51, 150.63, 144.89, 140.66, 139.62, 134.20, 129.52, 128.13, 125.10, 102.89, 87.65, 82.53, 82.50, 76.88, 76.87, 74.46, 74.36, 73.60, 73.54, 66.13, 63.60, 63.56, 58.58, 57.90, 57.87, 46.72, 46.49, 45.46, 27.21, 26.05, 16.41, 16.39, 16.37, 16.35.

[1551] Synthesis of 2'-OMe-5'-PO(OEt)2-Triazolyl methyl phosphonate Uridine D-PSM amidite.

[1552]

[1553] 2'-OMe-5'-PO(OEt)2-Triazolyl methyl phosphonate Uridine D-PSM amidite. Nucleoside 2'-OMe-5'-PO(OEt)2-Triazolyl methyl phosphonate Uridine (WV-NU-352, 910 mg) was converted to 2'-OMe-5'-PO(OEt)2-Triazolyl methyl phosphonate Uridine D-PSM amidite (914 mg, 63.6% yield) as an off-white solid.

[1554] LCMS: C28H38N6O11P2S (M-H): 727.18

[1555] ’H NMR (600 MHz, CDCI3) 8 8.90 (s, 1H), 8.04 (d, J = 8.2 Hz, 1H), 8.00 (s, 1H), 7.95 -7.91 (m, 2H), 7.70 - 7.65 (m, 1H), 7.59 (t, J = 7.9 Hz, 2H), 6.17 (d, J = 4.5 Hz, 1H), 5.76 (d, J = 8.2 Hz, 1H), 5.25 (d, J = 4.6 Hz, 1H), 5.03 (q, J = 6.1 Hz, 1H), 4.89 - 4.75 (m, 3H), 4.22 (t, J = 4.6 Hz, 1H), 4.19 - 4.09 (m, 4H), 3.65 (dq, J = 10.2, 5.9 Hz, 1H), 3.51 - 3.43 (m, 5H), 3.34 (dd, J = 14.5, 5.4 Hz, 1H), 3.12 (qd, J = 10.0, 4.0 Hz, 1H), 1.91 - 1.73 (m, 2H), 1.62 (qd, J = 7.3, 2.4 Hz, 1H), 1.29 (q, J = 6.8 Hz, 6H), 1.12 - 1.02 (m, 1H).

[1556] 31P NMR (243 MHz, CDCl3) δ 151.71, 15.62

[1557] 13C NMR (151 MHz, CDCI3) 6 163.21, 150.49, 145.06, 140.67, 139.63, 134.31, 129.59, 128.29, 125.09, 102.98, 87.71, 82.63, 74.64, 74.58, 73.63, 73.59, 66.55, 66.53, 63.74, 63.70, 58.40, 58.38, 58.36, 46.65, 46.42, 45.63, 27.60, 26.05, 26.03, 16.52, 16.51, 16.47.

[1558] Synthesis of 2'-Fluoro-5'-PO(OEt)2-Triazolyl Phosphonate Uridine L-PSM amidite

[1559]

[1560] Nucleoside (2'-Fluoro-5'-PO(OEt)2-Triazolyl Phosphonate Uridine (WV-NU-347A, 1.95 g) was converted to 2'-Fluoro-5'-PO(OEt)2-Triazolyl Phosphonate Uridine L-PSM amidite (2.05 g, 67.1% yield) as an off-white solid.

[1561] LCMS: C27H35FN6O10P2S (M-H): 715.21

[1562] ’H NMR (600 MHz, CDCI3) 88.89 (s, 1H), 8.18 (s, 1H), 7.98 - 7.94 (m, 2H), 7.67 - 7.63 (m, 1H), 7.57 (t, J = 7.8 Hz, 2H), 7.09 (d, J = 8.0 Hz, 1H), 5.74 (d, J = 8.0 Hz, 1H), 5.25 (ddd, J = 12.5, 5.7, 3.7 Hz, 1H), 4.81 (qd, J = 14.9, 4.1 Hz, 2H), 4.74 - 4.65 (m, 1H), 4.33 - 4.16 (m, 5H), 3.76 (dq, J = 10.0, 6.0 Hz, 1H), 3.63 - 3.51 (m, 2H), 3.39 (dd, J = 14.6, 4.1 Hz, 1H), 3.33 - 3.25 (m, 1H), 1.97 - 1.81 (m, 2H), 1.67 (dt, J = 12.2, 7.5 Hz, 1H), 1.35 (dt, J = 11.4, 7.0 Hz, 6H), 1.14 (dq, J = 11.9, 10.0 Hz, 1H).

[1563] 31P NMR (243 MHz, CDCI3) 6 151.89 (d, J = 5.3 Hz), 6.94.

[1564] 13C NMR (151 MHz, CDCI3) 6 162.63, 149.61, 143.08, 139.82, 134.21, 132.64, 132.42, 129.53, 128.39, 103.48, 95.05, 94.80, 92.65, 79.87, 75.07, 75.00, 66.52, 66.50, 63.44, 63.40, 63.26, 63.22, 58.28, 58.26, 49.92, 46.55, 46.32, 27.56, 26.22, 26.20, 16.48, 16.44.

[1565] 19F NMR (565 MHz, CDCI3) 6 -192.00 (d, J = 5.1 Hz).

[1566] Synthesis of 2'-Fluoro-5'-PO(POM)2-Triazolyl Phosphonate Uridine L-PSM amidite.

[1567]

[1568] 2'-Fluoro-5'-PO(POM)2-Triazolyl Phosphonate Uridine L-PSM amidite Nucleoside 2'-Fluoro-5'-PO(POM)2-Triazolyl Phosphonate Uridine (WV-NU-347, 5.92 g) was converted to 2'-Fluoro-5'-PO(POM)2-Triazolyl Phosphonate Uridine L-PSM amidite (6.18 g, 73.0% yield) as an off-white solid.

[1569] LCMS: C35H47N6O14P2S (M-H): 887.05’H-NMR (600 MHz, CDCI3) 68.85 (s, 1H), 8.10 (s, 1H), 7.98 - 7.94 (m, 2H), 7.67 - 7.63 (m, 1H), 7.57 (dd, J = 8.4, 7.2 Hz, 2H), 7.10 (d, J = 8.1 Hz, 1H), 5.85 - 5.70 (m, 5H), 5.36 - 5.29 (m, 2H), 5.24 (dq, J = 6.0, 4.1 Hz, 1H), 4.88 (dd, J = 15.0, 3.9 Hz, 1H), 4.75 (dd, J = 15.0, 2.9 Hz, 1H), 4.66 (dtd, J = 19.1, 8.7, 5.2 Hz, 1H), 4.27 (dt, J = 8.7, 3.4 Hz, 1H), 3.75 (dq, J = 9.8, 6.0 Hz, 1H), 3.62 - 3.49 (m, 2H), 3.39 (dd, J = 14.6, 4.1 Hz, 1H), 3.31 (tdd, J = 10.3, 8.6, 4.6 Hz, 1H), 1.90 (pq, J = 13.1, 7.5, 5.8 Hz, 2H), 1.70 - 1.64 (m, 1H), 1.20 (d, J = 7.8 Hz, 18H).

[1570] 31P-NMR (243 MHz, CDCI3) 5 151.40 (d, J = 4.9 Hz), 6.18.

[1571] 13C-NMR (151 MHz, CDCI3) 8 177.31, 162.45, 149.46, 143.24, 139.90, 134.17, 133.01, 129.51, 128.42, 103.64, 95.55, 95.29, 91.40, 82.34, 82.31, 79.53, 75.11, 75.04, 66.50, 66.48, 58.34, 49.18, 46.53, 46.29, 38.93, 38.92, 27.58, 26.97, 26.95, 26.25.

[1572] 19F NMR (565 MHz, CDCI3) 6 -190.96 (d, J = 4.9 Hz).

[1573] Synthesis of 2'-Fluoro-5'-PO(POM)2-Triazolyl Phosphonate Uridine D-PSM amidite.

[1574]

[1575] Nucleoside 5’-Triazolyl-PO(POM)2-2’-Fd-U (WV-NU-347, 4.92 g) was converted to 5’-Triazolyl-PO(POM)2-2’-Fd-U-D-PSM-amidite by general procedure (4.56 g, 64.8% yield) as an off-white solid.

[1576] LCMS: C35H47N6O14P2S (M-H ): 887.14

[1577] ‘H-NMR (600 MHz, CDCI3) 69.02 (s, 1H), 8.08 (s, 1H), 7.95 - 7.92 (m, 2H), 7.67 - 7.63 (m, 1H), 7.56 (t, J = 7.8 Hz, 2H), 7.09 (d, J = 8.0 Hz, 1H), 5.86 - 5.69 (m, 5H), 5.36 - 5.17 (m, 3H), 4.82 - 4.74 (m, 2H), 4.62 (dtd, J = 19.0, 8.4, 5.2 Hz, 1H), 4.29 (ddd, J = 8.2, 4.6, 3.1 Hz, 1H), 3.75 (dq, J = 9.9, 6.0 Hz, 1H), 3.59 (ddt, J = 14.9, 10.5, 7.7 Hz, 1H), 3.51 (dd,J = 14.6, 7.7 Hz, 1H), 3.40 (dd, J = 14.6, 4.7 Hz, 1H), 3.29 (tdd, J = 10.3, 8.9, 4.0 Hz, 1H), 1.96 - 1.78 (m, 2H), 1.66 (qd, J = 8.0, 2.6 Hz, 1H), 1.20 (s, 9H), 1.18 (s, 9H).

[1578] 31P-NMR (243 MHz, CDC13) 8 155.86 (d, J = 5.7 Hz), 6.09.

[1579] 13C-NMR (151 MHz, CDCI3) 6 177.30, 177.16, 162.61, 149.47, 143.35, 139.72, 134.17, 132.91, 129.50, 128.35, 103.57, 95.77, 95.51, 92.80, 91.55, 82.36, 82.33, 82.31, 82.28, 79.58, 79.54, 74.30, 74.24, 69.42, 66.31, 66.29, 60.56, 58.21, 58.19, 49.65, 46.65, 38.92, 38.88, 27.56, 26.96, 26.93, 26.25, 26.23, 21.22, 14.37.

[1580] 19F NMR (565 MHz, CDCI3) -190.60 (d, J = 5.7 Hz).

[1581] Synthesis of 2'-OMOE-5'-PO(POM)2-Triazolyl Phosphonate Uridine L-PSM amidite.

[1582]

[1583] 2'-OMOE-5'-PO(POM)2-Triazolyl Phosphonate Uridine L-PSM amidite. Nucleoside 2'-OMOE-5'-PO(POM)2-Triazolyl Phosphonate Uridine (WV-NU-348, 4.72 g) was converted to 2'-OMOE-5'-PO(POM)2-Triazolyl Phosphonate Uridine L-PSM amidite (4.86 g, 73.8% yield) as an off-white solid.

[1584] LCMS: C38H54N6O16P2S (M-H): 943.06

[1585] ‘H-NMR (600 MHz, CDCI3) 68.70 (s, 1H), 8.16 (s, 1H), 7.97 - 7.93 (m, 2H), 7.67 - 7.62 (m, 1H), 7.58 (dd, J = 8.4, 7.2 Hz, 2H), 7.05 (d, J = 8.1 Hz, 1H), 5.79 (dqd, J = 12.0, 5.2, 1.5 Hz, 4H), 5.71 (d, J = 8.0 Hz, 1H), 5.41 (d, J = 3.0 Hz, 1H), 5.24 - 5.19 (m, 1H), 4.74 (dd, J = 3.9, 1.9 Hz, 2H), 4.54 (ddd, J = 9.4, 7.2, 5.9 Hz, 1H), 4.28 (ddd, J = 8.0, 6.5, 3.7 Hz, 2H), 3.90 (ddd, J = 11.6, 5.3, 2.9 Hz, 1H), 3.75 - 3.68 (m, 2H), 3.62 - 3.47 (m, 4H), 3.38 (dd, J= 14.5, 4.2 Hz, 1H), 3.33 (s, 3H), 3.27 (tdd, J = 10.2, 8.0, 4.4 Hz, 1H), 1.96- 1.82 (m, 2H), 1.66 (dtd, J = 12.0, 6.4, 3.1 Hz, 1H), 1.18 (d, J = 4.6 Hz, 18H).

[1586] 31P-NMR (243 MHz, CDCI3) δ 152.23, 6.2813C-NMR (151 MHz, CDC13) 6 177.09, 162.76, 149.69, 143.16, 139.91, 134.20, 132.93, 132.70, 129.58, 128.24, 102.98, 95.43, 82.30, 82.27, 82.24, 80.48, 80.46, 80.29, 74.86, 74.80, 72.38, 71.19, 70.25, 66.50, 66.47, 59.13, 58.26, 58.23, 50.07, 46.56, 46.33, 38.88, 27.55, 26.96, 26.94, 26.24, 26.22.

[1587] Synthesis of 2'-OMOE-5'-PO(POM)2-Triazolyl Phosphonate Uridine D-PSM amidite.

[1588]

[1589] Nucleoside 2'-OMOE-5'-PO(POM)2-Triazolyl Phosphonate Uridine (WV-NU-348, 1.91 g) was converted to2'-OMOE-5'-PO(POM)2-Triazolyl Phosphonate Uridine D-PSM amidite. by general procedure (2.12 g, 79.5% yield) as an off-white solid.

[1590] LCMS: C38H54N6O16P2S (M-H): 943.20

[1591] ‘H-NMR (600 MHz, CDCI3) 88.94 (s, 1H), 8.14 (s, 1H), 7.96 - 7.93 (m, 2H), 7.69 - 7.65 (m, 1H), 7.58 (t, J = 7.8 Hz, 2H), 7.06 (d, J = 8.1 Hz, 1H), 5.83 - 5.75 (m, 4H), 5.71 (d, J = 8.0 Hz, 1H), 5.44 (d, J = 3.2 Hz, 1H), 5.25 (dt, J = 7.4, 5.3 Hz, 1H), 4.75 (qd, J = 14.6, 4.7 Hz, 2H), 4.56 (ddd, J = 9.7, 6.9, 5.8 Hz, 1H), 4.33 (dq, J = 7.4, 4.1, 3.5 Hz, 2H), 3.89 (ddd, J = 11.5, 4.9, 2.7 Hz, 1H), 3.75 (dq, J = 9.6, 6.0 Hz, 1H), 3.66 (ddd, J = 11.6, 7.3, 2.7 Hz, 1H), 3.60 - 3.45 (m, 4H), 3.39 (dd, J = 14.5, 5.0 Hz, 1H), 3.32 (s, 3H), 3.24 (tdd, J = 10.2, 8.7, 4.3 Hz, 1H), 1.95 - 1.76 (m, 2H), 1.65 (dddd, J = 12.1, 8.7, 5.5, 3.0 Hz, 1H), 1.18 (d, J = 6.5 Hz, 19H).

[1592] 31P-NMR (243 MHz, CDCI3) 6 154.99, 6.18.

[1593] 13C-NMR (151 MHz, CDCI3) 6 176.99, 162.93, 149.78, 143.31, 139.89, 134.25, 132.78, 132.54, 129.55, 128.33, 102.93, 95.38, 82.27, 82.26, 82.22, 80.59, 80.56, 80.31, 74.73, 74.67, 72.46, 70.99, 70.96, 70.88, 66.27, 59.17, 58.31, 50.55, 46.79, 46.56, 38.87, 38.86, 27.59, 26.94, 26.92, 26.24, 26.21.Synthesis of 2'-LNA-5'-PO(POM)2-Triazolyl Phosphonate Uridine L-PSM amidite.

[1594]

[1595] 2'-LNA-5'-PO(POM)2-Triazolyl Phosphonate Uridine L-PSM amidite Nucleoside, 2'-LNA-5'-PO(POM)2-Triazolyl Phosphonate Uridine (WV-NU-349, 1 99 g) was converted to2'-LNA-5'-PO(POM)2-Triazolyl Phosphonate Uridine L-PSM amidite (1.99 g, 72.5% yield) as an off-white solid.

[1596] LCMS: C36H48N6O15P2S (M-H ): 897.09

[1597] ‘H-NMR (600 MHz, CDCI3) 88.46 (s, 1H), 8.38 (s, 1H), 7.95 - 7.92 (m, 2H), 7.70 - 7.66 (m, 1H), 7.62 - 7.56 (m, 2H), 7.10 (d, J = 8.2 Hz, 1H), 5.85 - 5.76 (m, 4H), 5.71 (d, J = 8.2 Hz, 1H), 5.62 (s, 1H), 5.30 - 5.24 (m, 1H), 5.13 (d, J = 15.3 Hz, 1H), 4.91 (d, J = 15.3 Hz, 1H), 4.59 (s, 1H), 4.17 (dd, J = 14.8, 7.8 Hz, 2H), 3.90 (d, J = 8.3 Hz, 1H), 3.73 - 3.65 (m, 1H), 3.54 (dddd, J = 21.7, 14.3, 8.3, 3.3 Hz, 2H), 3.36 (dd, J = 14.3, 3.1 Hz, 1H), 3.26 (tdd, J = 10.4, 8.9, 3.9 Hz, 1H), 1.96 - 1.78 (m, 2H), 1.59 (dddd, J = 9.4, 7.4, 5.4, 2.4 Hz, 1H), 1.18 (d, J = 6.2 Hz, 19H).

[1598] 31P-NMR (243 MHz, CDCI3) δ 158.14, 5.44

[1599] 13C-NMR (151 MHz, CDCI3) 6 176.82, 176.80, 162.85, 149.77, 139.71, 138.38, 134.38, 133.33, 133.10, 129.71, 128.03, 102.53, 87.84, 86.20, 82.24, 82.22, 82.20, 79.50, 79.46, 74.00, 73.94, 72.36, 72.25, 72.17, 66.44, 57.66, 57.64, 46.76, 46.54, 38.84, 27.25, 26.94, 26.92, 26.11, 26.09.

[1600] Synthesis of 2'-LNA-5'-PO(POM)2-Triazolyl Phosphonate Uridine D-PSM amidite.

[1601]

[1602] 2'-LNA-5'-PO(POM)2-Triazolyl Phosphonate Uridine D-PSM amidite Nucleoside Synthesis of 2'-LNA-5'-PO(POM)2-Triazolyl Phosphonate Uridine (WV-NU-349, 2.01 g) was converted to Synthesis of 2'-LNA-5'-PO(POM)2-Triazolyl Phosphonate Uridine L-PSM amidite.

[1603] (1.89 g, 68.1% yield) as an off-white solid.

[1604] LCMS: C36H48N6O15P2S (M-H): 897.09

[1605] ‘H-NMR (600 MHz, CDCI3) 88.45 (s, 1H), 8.24 (s, 1H), 7.97 - 7.94 (m, 2H), 7.70 - 7.66 (m, 1H), 7.59 (t, J = 7.8 Hz, 2H), 6.78 (d, J = 8.2 Hz, 1H), 5.85 - 5.75 (m, 4H), 5.69 (d, J = 8.2 Hz, 1H), 5.62 (s, 1H), 5.14 - 5.09 (m, 1H), 4.90 (s, 2H), 4.58 (s, 1H), 4.14 - 4.07 (m, 2H), 4.03 (d, J = 5.8 Hz, 1H), 3.77 - 3.68 (m, 2H), 3.58 - 3.49 (m, 2H), 3.39 (dd, J = 14.6, 4.6 Hz, 1H), 3.25 (tdd, J= 10.2, 8.8, 3.9 Hz, 1H), 1.96 - 1.79 (m, 2H), 1.72 - 1.64 (m, 1H), 1.18 (d, J = 2.5 Hz, 19H).

[1606] 31P-NMR (243 MHz, CDCI3) δ 156.55, 5.24

[1607] 13C-NMR (151 MHz, CDCI3) 6 176.89, 162.40, 149.51, 139.47, 137.91, 134.33, 132.69, 132.46, 129.61, 128.37, 102.75, 88.26, 86.17, 82.25, 82.21, 82.18, 78.99, 74.56, 72.14, 72.09, 72.05, 66.38, 66.35, 58.01, 57.98, 47.13, 46.94, 46.71, 38.88, 27.50, 26.96, 26.20, 26.17, 14.37.

[1608] EXAMPLE 29. Synthesis of 5’-Triazolylphosphonate L-DPSE Amidites:

[1609] General Procedure:

[1610] Nucleoside (1.0 eq.) in an appropriate size three necked flask was azeotroped with anhydrous toluene (15 mL / g) and anhydrous acetonitrile (15 mL / g) and was dried for 24 hours on high vacuum. To the flask was added anhydrous THF (0.1-0.2 M solution) underargon and solution was cooled to 0°C. To the reaction mixture was added triethyl amine (2.2 eq.) followed by addition of L-DPSE-C1 (0.87 M) solution (1.6 eq.) over the period of 5-10 min. The reaction mixture was warmed to room temperature and reaction progress was monitored by HPLC. After disappearance of starting material, the reaction mixture was filtered through fritted glass tube. Reaction flask and precipitate was washed with anhydrous THF. Obtained filtrate was collected and solvent was removed under reduced pressure. The residue was purified by column chromatography (SiO2, 40-80% Ethyl acetate in Hexanes and 20-100% Acetonitrile in Ethyl acetate) to give 5’-Triazolylphosphonate L-DPSE Amidites as off-white solid.

[1611] Synthesis of 2’-OMe- 5’-PO(OCNE)i Triazolyl Phosphonate Uridine L-DPSE amidite

[1612]

[1613] Nucleoside 2’-OMe- 5’-PO(OCNE)2Triazolyl Phosphonate Uridine (WV-NU-336, 1 32 g) was converted to 2’-OMe- 5’-PO(OCNE)i Triazolyl Phosphonate Uridine L-DPSE amidite (795 mg, 38.4% yield) as an off-white solid.

[1614] LCMS: C37H44N8O9P2Si (M-H): 833.12

[1615] ’H NMR (600 MHz, CDC13) 88.56 (s, 1H), 8.19 (s, 1H), 7.56 - 7.49 (m, 5H), 7.36 - 7.30 (m, 7H), 6.93 (d, J = 8.1 Hz, 1H), 5.70 (d, J = 8.0 Hz, 1H), 5.22 (d, J = 3.2 Hz, 1H), 4.92 (dt, J = 8.5, 6.0 Hz, 1H), 4.63 - 4.50 (m, 2H), 4.46 - 4.39 (m, 5H), 4.15 (dd, J = 6.9, 3.8 Hz, 1H), 3.91 (dd, J = 5.7, 3.2 Hz, 1H), 3.61 (ddt, J = 14.4, 10.6, 7.6 Hz, 1H), 3.50 (dq, J = 9.4, 5.9 Hz, 1H), 3.38 (s, 3H), 3.22 (dtd, J = 10.6, 8.8, 7.6, 4.5 Hz, 1H), 2.87 - 2.78 (m, 4H), 1.90 (qd, J = 8.9, 4.6 Hz, 1H), 1.76 (q, J = 10.9, 10.0 Hz, 1H), 1.66 (dd, J = 14.7, 8.4 Hz, 1H), 1.48 (td, J= 13.2, 11.5, 5.0 Hz, 2H), 0.68 (s, 3H).

[1616] 31P NMR (243 MHz, CDC13) δ 152.57, 8.14

[1617] 13C NMR (151 MHz, CDCI3) 6 143.16, 136.75, 136.11, 134.74, 134.72, 134.51, 133.11, 132.89, 129.62, 129.57, 128.12, 128.08, 116.68, 116.64, 102.94, 95.21, 80.78, 80.76, 80.55,79.79, 79.72, 70.44, 68.06, 68.04, 61.71, 61.68, 61.63, 61.60, 59.17, 50.21, 46.88, 27.41, 26.09, 26.07, 20.04, 20.02, 19.99, 19.97, 17.90, -3.20.

[1618] EXAMPLE 30. Synthesis of siRNA 2’-OMe N-3-uridine

[1619]

[1620] WV-NU-346A

[1621] (((1 -(((2R,3R,4R,5R)-5-(2,6-di oxo-3, 6-dihydropyrimidin-l(2H)-yl)-3-hydroxy-4-methoxytetrahydrofuran-2-yl)methyl)- 1H- 1,2,3-triazol-4-yl)phosphoryl)bis(oxy))bis(methylene) bis(2,2-dimethylpropanoate) (WV-NU-346A)

[1622]

[1623] Step 1. For four batches: To a solution of compound 1 (25 g, 223.04 mmol) in HMDS (500 mL) was added (NH4)2SO4 (2.95 g, 22.30 mmol, 1.67 mL). The mixture was stirred at 140 °C for 4 h. TLC indicated compound 1 was consumed completely and one new spot formed. Cool the reaction mixture to 25 °C. The reaction mixture was concentrated under reduced pressure to remove HMDS. Compound 1A (228 g, crude) was obtained as a colorless oil. TLC: Petroleum ether: Ethyl acetate = 0: 1, Rf = 0.43.

[1624] Step 2. For four batches. To a solution of compound 1C (50 g, 108.12 mmol) in dioxane (1000 mL) was added Nl, Nl, N8, N8-tetramethylnaphthalene-l,8-diamine (69.51 g, 324.36mmol), trimethyloxonium;tetrafluoroborate (47.98 g, 324.36 mmol), then the mixture was stirred at 35 °C for 10 h. LCMS showed compound 1C was consumed completely and desired mass was detected. The mixture was concentrated. The residue was purified by column chromatography (SiO2, Petroleum ether: Ethyl acetate =1: 0 to 15: 1). Compound 2C (198 g, 96.12% yield) was obtained as a yellow oil.1H NMR (400 MHz, DMSO-d6) 5 = 8.11 - 8.00 (m, 6H), 7.73 - 7.63 (m, 3H), 7.59 - 7.45 (m, 6H), 6.72 (d, J = 4.3 Hz, 1H), 5.76 - 5.74 (m, 1H), 4.92 - 4.82 (m, 1H), 4.58 (d, J = 4.4 Hz, 2H), 4.41 - 4.38 (m, 1H), 3.40 (s, 3H); LCMS: (M+Na+): 499.2; TLC: Petroleum ether: Ethyl acetate = 3: 1, Rf = 0.40.

[1625] Step 3. For four batches: To a solution of compound 2C (49.5 g, 103.89 mmol) in EtOAc (800 mL) at -20 °C and then Cpd.lA (39.96 g, 155.83 mmol) and BF3. Et2O (191.68 g, 1.35 mol, 166.10 mL) under N2. The mixture was stirred at 0 ~ 25 °C for 12 h. LCMS showed compound 2C was consumed completely and desired mass was detected. The reaction mixture was adjusted to pH = 7 by sat. NaHCCL at 0 °C, and then extracted with EtOAc (1000 mL * 3). The residue was purified by column chromatography (SiO2, Petroleum ether: Ethyl acetate = 1: 0 to 0: 1). Compound 3C (150 g, 77.72% yield) was obtained as a white solid. ‘HNMR (400 MHz, DMSO-d6) 5 = 11.30 (br s, 1H), 8.04 - 7.93 (m, 4H), 7.72 - 7.59 (m, 2H), 7.58 - 7.39 (m, 5H), 6.32 (d, J = 2.1 Hz, 1H), 5.72 (br t, J = 7.0 Hz, 1H), 5.69 - 5.53 (m, 1H), 4.69 - 4.55 (...

Claims

CLAIMSWhat is claimed is:

1. A double-stranded RNAi (dsRNAi) agent capable of directing target-specific RNA interference, the dsRNAi agent comprising a guide strand and a passenger strand, wherein:the guide strand is complementary or substantially complementary to a target RNA sequence;the guide strand comprises a seed region at its 5’-end region that is capable of mediating the initial recognition of the target RNA sequence; andthe passenger strand comprises a backbone phosphoryl guanidine (PN) chiral center between the 5’ terminal (+1) nucleotide and the immediately downstream (+2) nucleotide.

2. The dsRNAi agent of claim 1, wherein the guide strand comprises a backbone PN chiral center in the seed region.

3. The dsRNAi agent of claim 1 or 2, wherein the backbone PN chiral center between the 5’ terminal (+1) nucleotide and the immediately downstream (+2) nucleotide of the passenger strand is in the Rp configuration.

4. The dsRNAi agent of any of claims 1-3, wherein the passenger strand further comprises a backbone PN chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide.

5. The dsRNAi agent of claim 4, wherein the backbone PN chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide of the passenger strand is in the Rp configuration.

6. The dsRNAi agent of any of claims 1-5, wherein the backbone PN chiral centercomprises the structure7. The dsRNAi agent of any of claims 1-6, wherein the backbone phosphoryl guanidine (PN) chiral center in the seed region is between the +3 nucleotide and the immediately downstream (+4) nucleotide, relative to the 5’ terminal nucleotide of the guide strand.

8. The dsRNAi agent of claim 7, wherein the backbone phosphoryl guanidine (PN) chiral center in the seed region of the guide strand is in the Sp configuration.

9. The dsRNAi agent of claim 8, wherein the nucleoside 3’ to the PN chiral center in the seed region comprises a 2’-F ribose modification.

10. The dsRNAi agent of any of claims 1-9, wherein the guide strand further comprises a backbone phosphoryl guanidine (PN) chiral center between the +10 nucleotide and the immediately downstream (+11) nucleotide, relative to the 5’ terminal nucleotide of the guide strand.

11. The dsRNAi agent of claim 10, wherein the nucleoside 3’ to the PN chiral center between the +10 nucleotide and the immediately downstream (+11) nucleotide, relative to the 5’ terminal nucleotide of the guide strand, comprises a 2’-F ribose modification.

12. The dsRNAi agent of claim 11, wherein the backbone phosphoryl guanidine (PN) chiral center between the +10 nucleotide and the immediately downstream (+11) nucleotide, relative to the 5’ terminal nucleotide of the guide strand, is in the Rp configuration.

13. The dsRNAi agent of any of claims 1-12, wherein the guide strand comprises a 5’ phosphate modification.

14. The dsRNAi agent of claim 13, wherein the 5’ phosphate modification is a 5’ phosphate mimic modification.

15. The dsRNAi agent of claim 14, wherein the 5’ phosphate mimic modification iswherein:the base is N3U, or is selected from A, C, G, T, U, abasic, and modified nucleobases other than N3U; andR1is selected from H, OH, O-alkyl, O-methyl (O-Me), F, O-methoxyethyl (MOE), and 2’-(9,4’C-methylene-bridged or locked nucleic acid (2’,4’-BNA or LNA).

16. The dsRNAi agent of claim 15, wherein R1is O-methyl (O-Me).

17. The dsRNAi agent of any of claims 1-16, wherein the guide strand further comprises a backbone phosphoryl guanidine (PN) chiral center between the 3 ’ terminal (N) nucleotide and the penultimate (N-l) nucleotide, and / or a backbone phosphoryl guanidine (PN) chiral center between the penultimate (N-l) nucleotide and the immediately upstream (N-2) nucleotide.

18. The dsRNAi agent of claim 17, wherein the backbone phosphoryl guanidine (PN) chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide, and / or the backbone phosphoryl guanidine (PN) chiral center between the penultimate (N- 1) nucleotide and the immediately upstream (N-2) nucleotide, is / are in the Ap configuration.

19. The dsRNAi agent of claim 18, wherein the guide strand does not comprise a backbone phosphoryl guanidine (PN) chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide.

20. The dsRNAi agent of claim 19, wherein the guide strand comprises a phosphorothioate (PS) chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide.

21. The dsRNAi agent of claim 20, wherein the phosphorothioate (PS) chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide of the guide strand is in the Sp configuration.

22. The dsRNAi agent of any of claims 1-21, wherein the guide strand comprises a phosphoryl guanidine (PN) cap at its 5 ’-end (5 ’-end PN cap).

23. The dsRNAi agent of claim 22, wherein the 5’-end PN cap is selected fromwherein:the base is N3U, or is selected from A, C, G, T, U, abasic, and modified nucleobasesother than N3U; andR1is selected from H, OH, O-alkyl, O-methyl (O-Me), F, O-methoxyethyl (MOE), and 2’-O,4’C-methylene-bridged or locked nucleic acid (2’,4’-BNA or LNA).

24. The dsRNAi agent of claim 23, wherein R1is O-methyl (O-Me).

25. The dsRNAi agent of any of claims 1-24, wherein the guide strand comprises a natural phosphate linkage (PO) between the 5’ terminal (+1) nucleotide and the immediately downstream (+2) nucleotide, and / or a natural phosphate linkage (PO) between the +2 nucleotide and the +3 nucleotide, relative to the 5’ terminal nucleotide.

26. A double-stranded RNAi (dsRNAi) agent capable of directing target-specific RNA interference, the dsRNAi agent comprising a guide strand and a passenger strand, wherein:the guide strand is complementary or substantially complementary to a target RNA sequence;the guide strand comprises a seed region at its 5’-end region that is capable of mediating the initial recognition of the target RNA sequence;andthe guide strand comprises a phosphoryl guanidine (PN) cap at its 5 ’-end (5 ’-end PN cap).

27. The dsRNAi of claim 1, wherein the guide strand comprises a backbone phosphoryl guanidine (PN) chiral center in the seed region.

28. The dsRNAi agent of claims 26 or 27, wherein the 5’-end PN cap is selected fromthe base is N3U, or is selected from A, C, G, T, U, abasic, and modified nucleobases other than N3U; andR1is selected from H, OH, O-alkyl, O-methyl (O-Me), F, O-methoxyethyl (MOE), and 2’-O,4’C-methylene-bridged or locked nucleic acid (2’,4’-BNA or LNA).

29. The dsRNAi agent of claim 28, wherein R1is O-methyl (O-Me).

30. A double-stranded RNAi (dsRNAi) agent capable of directing target-specific RNA interference, the dsRNAi agent comprising a guide strand and a passenger strand, wherein:the guide strand is complementary or substantially complementary to a target RNA sequence;the guide strand comprises a seed region at its 5’-end region that is capable of mediating the initial recognition of the target RNA sequence;the guide strand comprises a backbone phosphoryl guanidine (PN) chiral center in the seed region; andthe guide strand comprises a natural phosphate linkage (PO) between the 5’ terminal (+1) nucleotide and the immediately downstream (+2) nucleotide, and / or a natural phosphate linkage (PO) between the +2 nucleotide and the +3 nucleotide, relative to the 5’ terminal nucleotide.

31. The dsRNAi agent of claim 30, wherein the guide strand comprises a 5’ phosphate modification.

32. The dsRNAi agent of claim 31, wherein the 5’ phosphate modification is a 5’ phosphate mimic modification.

33. The dsRNAi agent of claim 32, wherein the 5’ phosphate mimic modification is, wherein:the base is N3U, or is selected from A, C, G, T, U, abasic, and modified nucleobases other than N3U; andR1is selected from H, OH, O-alkyl, O-methyl (O-Me), F, O-methoxyethyl (MOE), and 2’-(9,4’C-methylene-bridged or locked nucleic acid (2’,4’-BNA or LNA).

34. The dsRNAi agent of claim 33, wherein R1is O-methyl (O-Me).

35. A double-stranded RNAi (dsRNAi) agent capable of directing target-specific RNAinterference, the dsRNAi agent comprising a guide strand and a passenger strand, wherein: the guide strand is complementary or substantially complementary to a target RNA sequence;the guide strand comprises a seed region at its 5’-end region that is capable of mediating the initial recognition of the target RNA sequence; andthe guide strand comprises a backbone phosphoryl guanidine (PN) chiral center in the seed region,wherein the nucleoside 3’ to the PN chiral center in the seed region comprises a 2’-F ribose modification.

36. The dsRNAi agent of claim 35, wherein the backbone phosphoryl guanidine (PN) chiral center in the seed region is between the +3 nucleotide and the immediately downstream (+4) nucleotide, relative to the 5’ terminal nucleotide of the guide strand.

37. The dsRNAi agent of claim 35 or 36, wherein the backbone phosphoryl guanidine (PN) chiral center in the seed region of the guide strand is in the Sp configuration.

38. The dsRNAi agent of any of claims 35-37, wherein the guide strand further comprises a backbone phosphoryl guanidine (PN) chiral center between the +10 nucleotide and the immediately downstream (+11) nucleotide, relative to the 5’ terminal nucleotide of the guide strand, wherein the nucleoside 3’ to the PN chiral center comprises a 2’-F ribose modification.

39. The dsRNAi agent of claim 38, wherein the backbone phosphoryl guanidine (PN) chiral center between the +10 nucleotide and the immediately downstream (+11) nucleotide, relative to the 5’ terminal nucleotide of the guide strand, is in the Rp configuration.

40. The dsRNAi agent of any of claims 35-38, wherein the guide strand further comprises a backbone phosphoryl guanidine (PN) chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide, and / or a backbone phosphoryl guanidine (PN) chiral center between the penultimate (N-l) nucleotide and the immediately upstream (N-2) nucleotide.

41. The dsRNAi agent of claim 40, wherein the backbone phosphoryl guanidine (PN)chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide, and / or the backbone phosphoryl guanidine (PN) chiral center between the penultimate (N- 1) nucleotide and the immediately upstream (N-2) nucleotide, is / are in the Rp configuration.

42. The dsRNAi agent of claim 41, wherein the guide strand does not comprise a backbone phosphoryl guanidine (PN) chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide.

43. The dsRNAi agent of claim 42, wherein the guide strand does not comprise a backbone phosphoryl guanidine (PN) chiral center between the penultimate (N-l) nucleotide and the immediately upstream (N-2) nucleotide.

44. The dsRNAi agent of claim 43, wherein the guide strand comprises a phosphorothioate (PS) chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide.

45. The dsRNAi agent of claim 44, wherein the phosphorothioate (PS) chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide of the guide strand is in the Sp configuration.

46. The dsRNAi agent of any of claims 35-45, wherein the guide strand comprises a 5’ phosphate modification.

47. The dsRNAi agent of claim 46, wherein the 5’ phosphate modification is a 5’ phosphate mimic modification.

48. The dsRNAi agent of claim 47, wherein the 5’ phosphate mimic modification is, wherein:the base is N3U, or is selected from A, C, G, T, U, abasic, and modified nucleobases other than N3U; andR1is selected from H, OH, O-alkyl, O-methyl (O-Me), F, O-methoxyethyl (MOE), and 2’-O,4’C-methylene-bridged or locked nucleic acid (2’,4’-BNA or LNA).

49. The dsRNAi agent of claim 46, wherein R1is O-methyl (O-Me).

50. A double-stranded RNAi (dsRNAi) agent capable of directing target-specific RNA interference, the dsRNAi agent comprising a guide strand and a passenger strand, wherein:the guide strand is complementary or substantially complementary to a target RNA sequence;the guide strand comprises a seed region at its 5’-end region that is capable of mediating the initial recognition of the target RNA sequence; andthe guide strand comprises a contiguous stretch of five backbone phosphorothioate (PS) chiral centers between the +13 nucleotide and the +18 nucleotide, relative to the 5’ terminal nucleotide, and / or a contiguous stretch of four backbone phosphorothioate (PS) chiral centers between the +19 nucleotide and the 3’ terminal (N) nucleotide.

51. The dsRNAi agent of claim 50, wherein the guide strand comprises a backbone phosphoryl guanidine (PN) chiral center in the seed region.

52. The dsRNAi agent of claim 50 or 51, wherein the seed region comprises nucleotides at positions 2-6, at positions 2-7, or at positions 2-8, relative to the 5 ’-end of the guide strand.

53. The dsRNAi agent of any of claims 50-52, wherein the backbone phosphoryl guanidine (PN) chiral center in the seed region is between the +3 nucleotide and the immediately downstream (+4) nucleotide, relative to the 5’ terminal nucleotide of the guide strand.

54. The dsRNAi agent of any of claims 50-53, wherein the backbone phosphoryl guanidine (PN) chiral center in the seed region of the guide strand is in the Sp configuration.

55. The dsRNAi agent of any of claims 50-54, wherein the backbone phosphoryl guanidine(PN) chiral center comprises the structure56. The dsRNAi agent of any of claims 50-55, wherein the contiguous stretch of five backbone phosphorothioate (PS) chiral centers between the +13 nucleotide and the +18 nucleotide, relative to the 5’ terminal nucleotide, and / or the contiguous stretch of four backbone phosphorothioate (PS) chiral centers between the +19 nucleotide and the 3’ terminal (N) nucleotide, of the guide strand, are in the 5p configuration.

57. The dsRNAi agent of any of claims 50-56, wherein the passenger strand comprises a backbone phosphorothioate (PS) chiral center between the 5’ terminal (+1) nucleotide and the immediately downstream (+2) nucleotide, and / or a backbone phosphorothioate (PS) chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-l) nucleotide.

58. The dsRNAi agent of claim 57, wherein the backbone phosphorothioate (PS) chiral center between the 5’ terminal (+1) nucleotide and the immediately downstream (+2) nucleotide, and / or the backbone phosphorothioate (PS) chiral center between the 3’ terminal (N) nucleotide and the penultimate (N-l), of the passenger strand, is / are in the Sp configuration.

59. The dsRNAi agent of any of claims 50-58, wherein the guide strand further comprises a backbone phosphoryl guanidine (PN) chiral center between the +7 nucleotide and the +8 nucleotide, and / or a backbone phosphoryl guanidine (PN) chiral center between the +18 nucleotide and the +19 nucleotide thereof.

60. The dsRNAi agent of claim 50-59, wherein the backbone phosphoryl guanidine (PN) chiral center between the +7 nucleotide and the +8 nucleotide, and / or the backbone phosphoryl guanidine (PN) chiral center between the +18 nucleotide and the +19 nucleotide, of the guide strand, is / are in the 5p configuration.

61. The dsRNAi agent of claim 59 or 60, wherein the backbone phosphoryl guanidine (PN) chiral center between the +7 nucleotide and the +8 nucleotide, and / or the backbone phosphoryl guanidine (PN) chiral center between the +18 nucleotide and the +19 nucleotidethereof, comprises the structure62. The dsRNAi agent of any of claims 50-61, wherein the passenger strand comprises a backbone phosphoryl guanidine (PN) chiral center between the +7 nucleotide and the immediately downstream (+8) nucleotide, and / or a backbone phosphoryl guanidine (PN) chiral center between the +15 nucleotide and the immediately downstream (+16) nucleotide.

63. The dsRNAi agent of claim 62, wherein the backbone phosphoryl guanidine (PN) chiral center between the +7 nucleotide and the immediately downstream (+8) nucleotide, and / or the backbone phosphoryl guanidine (PN) chiral center between the +15 nucleotide and the immediately downstream (+16) nucleotide, of the passenger strand, is / are in the Ap configuration.

64. The dsRNAi agent of claim 59 or 60, wherein the backbone phosphoryl guanidine (PN)chiral center comprises the structure65. A double-stranded RNAi (dsRNAi) agent capable of directing target-specific RNA interference, the dsRNAi agent comprising a guide strand and a passenger strand, wherein:the guide strand is complementary or substantially complementary to a target RNA sequence;the guide strand comprises a seed region at its 5 ’-end region that is capable of mediating the initial recognition of the target RNA sequence; andthe guide strand comprises one or more N-3-uridine base modifications (N3U) havingthe structure66. The dsRNAi agent of claim 65, wherein the seed region comprises nucleotides at positions 2-6, at positions 2-7, or at positions 2-8, relative to the 5 ’-end of the guide strand.

67. The dsRNAi agent of claim 65 or 66, wherein the guide strand comprises a backbone phosphoryl guanidine (PN) chiral center.

68. The dsRNAi agent of claim 67, wherein the backbone phosphoryl guanidine (PN) chiralcenter is in the seed region.

69. The dsRNAi agent of claim 67 and 68, wherein the backbone phosphoryl guanidine (PN) chiral center is in the Sp configuration.

70. The dsRNAi agent of any of claims 65-69, wherein the guide strand comprises a contiguous stretch of four backbone phosphorothioate (PS) chiral centers between the +19 nucleotide and the 3’ terminal (N) nucleotide.

71. The dsRNAi agent of any of claims 65-70, wherein the guide strand comprises an N3U base modification at the 5’ terminal (+1) nucleotide.

72. The dsRNAi agent of any of claims 65-70, wherein the guide strand comprises an N3U base modification at the 3’ terminal nucleotide, the penultimate (N-l) nucleotide, or at both the 3’ terminal nucleotide and the penultimate (N-l) nucleotide.

73. The dsRNAi agent of claim 72, wherein the guide strand comprises an N3U base modification at the penultimate (N-l) nucleotide.

74. The dsRNAi agent of any of claims 65-73, further comprising a 5’ phosphate modification.

75. The dsRNAi agent of claim 74, wherein the 5’ phosphate modification is a 5’ phosphate mimic modification.

76. The dsRNAi agent of claim 75, wherein the 5’ phosphate mimic modification is selected fromwherein:the base is N3U, or is selected from A, C, G, T, U, abasic, and modified nucleobases other than N3U;R1is selected from H, OH, O-alkyl, O-methyl (O-Me), F, O-methoxyethyl (MOE), and 2’-O,4’C-methylene-bridged or locked nucleic acid (2’,4’-BNA or LNA); andR2is selected from alkyl, methyl, ethyl, isopropyl, propyl, cyclohexyl, benzyl, phenyl, tolyl, xylyl, aryl, and arene group.

77. The dsRNAi agent of claim 76, wherein the 5’ phosphate mimic modification is78. The dsRNAi agent of claim 76 or 77, wherein R1is O-Me.

79. The dsRNAi agent of claim 76, wherein R2in80. The dsRNAi agent of any of claims 65-79, wherein the guide strand further comprises a backbone phosphorothioate (PS) chiral center in the 5p configuration between the 5’terminal (+1) nucleotide and the immediately downstream (+2) nucleotide, and a backbone PS chiral center in the A'p configuration between the +2 nucleotide and immediately downstream (+3) nucleotide.

81. The dsRNAi agent of any of claims 65-79, wherein the guide strand further comprises a backbone phosphorothioate (PS) chiral center in the 5p configuration between the 5’ terminal (+1) nucleotide and the immediately downstream (+2) nucleotide, and wherein the backbone linkage between the +2 nucleotide and the immediately downstream (+3) nucleotide of the guide strand is an unmodified phosphodiester (PO) linkage.

82. A double-stranded RNAi (dsRNAi) agent capable of directing target-specific RNA interference, the dsRNAi agent comprising a guide strand and a passenger strand, wherein the guide strand is complementary or substantially complementary to a target RNA sequence; wherein the guide strand comprises a 5’ phosphate modification; and wherein the guide strand further comprises a backbone phosphorothioate (PS) chiral center in the 5p configuration between the 5’ terminal (+1) nucleotide and the immediately downstream (+2) nucleotide, and a backbone PS chiral center in the 5p or Rp configuration between the +2 nucleotide and immediately downstream (+3) nucleotide.

83. A double-stranded RNAi (dsRNAi) agent capable of directing target-specific RNA interference, the dsRNAi agent comprising a guide strand and a passenger strand, wherein the guide strand is complementary or substantially complementary to a target RNA sequence; wherein the guide strand comprises a 5’ phosphate modification; wherein the guide strand further comprises a backbone phosphorothioate (PS) chiral center in the 5p configuration between the 5’ terminal (+1) nucleotide and the immediately downstream (+2) nucleotide; and wherein the backbone linkage between the +2 nucleotide and the immediately downstream (+3) nucleotide of the guide strand is an unmodified phosphodiester (PO) linkage.

84. The dsRNAi agent of claim 82, wherein the backbone PS chiral center between the +2 nucleotide and immediately downstream (+3) nucleotide is in the Sp configuration.

85. The dsRNAi agent of claim 82, wherein the backbone PS chiral center between the +2 nucleotide and immediately downstream (+3) nucleotide is in the Rp configuration86. The dsRNAi agent of claims 82-85, wherein the 5’ phosphate modification is a 5’ phosphate mimic modification.

87. The dsRNAi agent of claim 86, wherein the 5’ phosphate mimic modification is selected from:the base is N3U, or is selected from A, C, G, T, U, abasic, and modified nucleobases other than N3U;R1is selected from H, OH, O-alkyl, O-methyl (O-Me), F, O-methoxyethyl (MOE), and 2’-O,4’C-methylene-bridged or locked nucleic acid (2’,4’-BNA or LNA); and R2is selected from alkyl, methyl, ethyl, isopropyl, propyl, cyclohexyl, benzyl, phenyl, tolyl, xylyl, aryl, and arene group.

88. The dsRNAi agent of claim 87, wherein the 5’ phosphate mimic modification is89. The dsRNAi agent of claim 87 or 88, wherein the R1is LNA bridge to the 4’ position.

90. The dsRNAi agent of claim 87 or 88, wherein the R1is MOE.

91. The dsRNAi agent of claim 87 or 88, wherein the R1is F.

92. The dsRNAi agent of claim 87, wherein R2in93. The dsRNAi agent of claim 87, wherein the 5’ phosphate mimic modification is, wherein the base is U or abasic, R1is H or O-alkyl.

94. The dsRNAi agent of claim 93, wherein R1is O-C16 alkyl.

95. The dsRNAi agent of claims 93-94, wherein R6is H.

96. The dsRNAi agent of claim 87, wherein the 5’ phosphate mimic modification iswherein R1is O-Me and R6is H.

97. The dsRNAi agent of claim 96, wherein98. The dsRNAi agent of claim 87, wherein the 5’ phosphate mimic modification is, wherein the base is abasic and R1is H.

99. The dsRNAi agent of claim 87, wherein the 5’ phosphate mimic modification is,wherein the R1is O-Me and R6is H.

100. The dsRNAi agent of any of the preceding claims, wherein the guide strand further comprises a backbone phosphoryl guanidine (PN) chiral center in the A'p configuration between the +3 nucleotide and the immediately downstream (+4) nucleotide.

101. The dsRNAi agent of any of the preceding claims, wherein the guide strand further comprises backbone PS chiral centers in 5p configuration between the 3’ terminal nucleotide and the penultimate (N-l) nucleotide and between the penultimate (N-l) nucleotide and the immediately upstream (N-2) nucleotide.

102. The dsRNAi agent of any of the preceding claims, wherein the guide strand comprises an Rp, Sp, or stereorandom non-negatively charged intemucleotidic linkage between the tenth (+10) and eleventh (+11) nucleotides, relative to the 5’ terminal nucleotide.

103. The dsRNAi agent of claim 102, wherein the guide strand further comprises a backbone PN chiral center between the +10 and the +11 nucleotides is in the Rp configuration104. The dsRNAi agent of any of the preceding claims, wherein the guide strand comprises one or more Rp, 5p, or stereorandom non-negatively charged intemucleotidic linkage occurs between any two adjacent nucleotides between the second (+2) nucleotide relative to the 5’ terminal nucleotide of the guide strand and the penultimate 3’ (N-l) nucleotide of the guide strand, where N is the 3’ terminal nucleotide.

105. The dsRNAi agent of any of the preceding claims, wherein the guide strand comprises a 2’ modification, of the 3’ nucleotide of a nucleotide pair linked by an Rp, Sp, or stereorandom non-negatively charged internucleotidic linkage.

106. The dsRNAi agent of any of the preceding claims, wherein the guide strand comprises an Rp, Sp, or stereorandom non-negatively charged internucleotidic linkage between the seventh (+7) and eighth (+8) nucleotides, relative to the 5’ terminal nucleotide.

107. The dsRNAi agent of any of the preceding claims, wherein the guide strand comprises one or more backbone phosphorothioate chiral centers in Rp or Sp configuration where linkage occurs between any two adjacent nucleotides between the penultimate 3’ nucleotide of the guide strand, where N is the 3’ terminal nucleotide, and the upstream N-10 nucleotide.

108. The dsRNAi agent of any of the preceding claims, wherein the passenger strand comprises one or more Rp, Sp, or stereorandom non-negatively charged internucleotidic linkage occurs upstream, i.e., in the 5’ direction, relative to the central nucleotide of the passenger strand.

109. The dsRNAi agent of any of the preceding claims, wherein the passenger strand comprises one or more Rp, Sp, or stereorandom non-negatively charged internucleotidic linkage occurs downstream, i.e., in the 3’ direction, relative to the central nucleotide of the passenger strand.

110. The dsRNAi agent of any of the preceding claims, wherein the passenger strand comprises one or more backbone phosphorothioate chiral centers in Rp or Sp configuration internucleotidic linkage occurs upstream, i.e., in the 5’ direction, relative to the central nucleotide of the passenger strand.

111. The dsRNAi agent of any of the preceding claims, wherein the passenger strand comprises one or more backbone phosphorothioate chiral centers in Rp or Sp configuration internucleotidic linkage internucleotidic linkage occurs downstream, i.e., in the 3’ direction, relative to the central nucleotide of the passenger strand.

112. The dsRNAi agent of any of the preceding claims, wherein the passenger strand incombination with one or more of the aforementioned guide strands, comprises one or more modified sugars between the 5’ terminal (+1) nucleotide and the penultimate (N- 1) nucleotide.

113. The dsRNAi agent of any of the preceding claims, wherein the passenger strand comprises one or more of:a. 0-n Rp, Sp, or stereorandom non-negatively charged intemucleotidic linkages, where n is about 1 to 49;b. one or more backbone chiral centers in Rp or Sp configuration;c. one or more backbone phosphoryl guanidine chiral centers in the Rp configuration between the +7 nucleotide and the immediately downstream (+8) nucleotide, i.e., in the 3’ direction;d. one or more backbone phosphoryl guanidine chiral centers in the Rp configuration between the +15 nucleotide and the immediately downstream (+16) nucleotide, i.e., in the 3’ direction; and / ore. backbone phosphorothioate chiral centers in the Sp configuration between the 5’ terminal (+1) nucleotide and the immediately downstream, i.e., in the 3’ direction, (+2) nucleotide and between the 3’ terminal nucleotide and the penultimate (N-l) nucleotide.

114. The dsRNAi agent of any of the preceding claims, wherein each strand of the dsRNAi agent independently has a length of about 15 to about 49 nucleotides.

115. The dsRNAi agent of any of the preceding claims, wherein the Rp, Sp, or stereorandom non-negatively charged backbone intemucleotidic linkages have neutral charge.

116. The dsRNAi agent of claim 115, wherein the neutral backbone intemucleotidiclinkage is, wherein n is about 0 to 49 and m is about 0 to 49.

117. The dsRNAi agent of claim 116, wherein the guide strand comprises a linkagehaving the following structurebetween the third (+3) and fourth (+4) nucleotides of the guide strand, between the tenth (+10) and eleventh (+11) nucleotides of the guide strand, or both.

118. The dsRNAi agent of claim 116, wherein the guide strand comprises a linkage having the following structurebetween the third (+3) and fourth (+4) nucleotides of the guide strand, between the seventh (+7) and eighth (+8) nucleotides of the guide strand, between the tenth (+10) and eleventh (+11) nucleotides of the guide strand, between the eighteenth (+18) and nineteenth (+19) nucleotides of the guide strand, or combinations thereof.

119. The dsRNAi agent of claim 116, wherein the passenger strand comprises a linkagehaving the following structure, where n is about 0 to 49 and m is about 0 to 49, at 5’ to the central nucleotide of the passenger strand, 3’ to the central nucleotide of the passenger strand, or both.

120. The dsRNAi agent of claim 116, wherein the passenger strand comprises a linkagehaving the following structure, wherein n is about 11 to 49 and m is 0.

121. The dsRNAi agent of claim 120, wherein n is 11 or 15.

122. The dsRNAi agent of any of the preceding claims, wherein the passenger strand comprises:i. a non-negatively charged backbone internucleotidic linkage in the Rp configuration between the +7 nucleotide and the +8 nucleotide;ii. a non-negatively charged backbone internucleotidic linkage in the Rp configuration between the +15 nucleotide and the +16 nucleotide; and / oriii. backbone phosphorothioate chiral centers in the Sp configuration between the 5’ terminal (+1) nucleotide and the +2 nucleotide and between the 3’ terminal nucleotide and the penultimate (N-l) nucleotide.

123. The dsRNAi agent of any of the preceding claims, wherein the passenger strand comprises:i.the Rp configuration between the +7 nucleotide and the +8 nucleotide;the Rp configuration between the +15 nucleotide and the +16 nucleotide; andiii. backbone phosphorothioate chiral centers in the Sp configuration between the +1 nucleotide and the +2 nucleotide and between the 3’ terminal nucleotide and the penultimate (N-l) nucleotide.

124. The dsRNAi agent of any of the preceding claims, wherein the passenger strand comprises:the Rp configuration between the +7 nucleotide and the +8 nucleotide; andbackbone phosphorothioate chiral centers in the Sp configuration between the +1 nucleotide and the +2 nucleotide and between the 3’ terminal nucleotide and the penultimate (N-l) nucleotide.

125. A method for reducing level and / or activity of a transcript or a protein encoded thereby comprising administering to a cell expressing the transcript a dsRNAi agent of any of the preceding claims, wherein the guide strand of the dsRNAi agent comprises a targeting-binding sequence that is completely complementary to a target sequence in the transcript.

126. The method of claim 125, wherein the cell is an immune cell, a blood cell, a cardiac cell, a lung cell, an optic cell, a muscle cell, a liver cell, a kidney cell, a cell of the central nervous system, or a cell of the peripheral nervous system.

127. The method of claim 126, wherein the cell of the central nervous system is a brain cell.

128. The method of any of claims 125-127, wherein when the dsRNAi agent is contacted with a cell comprising transcripts of both the target allele and another allele of the same nucleic acid sequence, it shows suppression of transcripts of the particular allele at a level that is:a. greater than when the dsRNAi agent is absent;b. greater than a level of suppression observed for another allele of the same nucleic acid sequence; orc. both greater than when the dsRNAi agent is absent, and greater than a level of suppression observed for another allele of the same nucleic acid sequence.d. of suppression observed for another allele of the same nucleic acid sequence.

Images