Synthesis of antibacterial aminoglycoside analogs

Abstract

To provide methods for preparing antibacterial sisomicin-type aminoglycoside compounds.SOLUTION: The present disclosure relates to novel methods for preparing antibacterial sisomicin-type aminoglycoside compounds, as well as, to related intermediates and crystal forms of the intermediates useful in such methods. The present disclosure provides processes for preparing compounds of formula (9), which includes plazomicin, that are scalable, reproducible at a commercial scale, and with good yields. These processes comprise reactions that can provide novel intermediate compounds obtained through experimentation and development of new combinations of reaction conditions. The processes may also comprise crystallization of certain intermediates. The crystallization of these particular intermediates unexpectedly contributes to improvements in purification (e.g., lower impurities), and can simplify the purification compared to prior methods of purification.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 62 / 574,544, filed October 19, 2017, the contents of which are incorporated herein by reference in their entirety.

[0002] Statement of Government Interest This invention was made with government funds from the Biomedical Advanced Research and Development Authority, Office of the Assistant Secretary for Preparedness and Response, Office of the Secretary, Department of Health and Human Services under Contract No. HHSO100201000046C. The government has certain rights in this invention.

[0003] The present disclosure relates to novel methods for preparing antibacterial aminoglycoside compounds, as well as related intermediates and crystalline forms of intermediates useful in such methods. [Background technology]

[0004] Currently, at least 30% of all hospitalized patients receive at least one treatment with antibiotics, curing millions of potentially fatal infections. These medications have become some of the most misused medicines available to physicians. However, one consequence of widespread use of antimicrobials is the emergence of antibiotic-resistant pathogens, resulting in an ever-increasing need for new drugs.

[0005] When the antibacterial activity of a new drug is first tested, a pattern of susceptibility and resistance is usually defined. Unfortunately, this activity spectrum can subsequently change significantly as microorganisms evolve a series of clever changes that allow them to survive in the presence of antibiotics. The mechanisms of drug resistance vary between microorganisms and between drugs.

[0006] Efforts to develop new aminoglycoside antibiotics active against multidrug-resistant Gram-negative bacteria have led to sisomicin and neomycin analogs modified at the 6'- and N-1 positions. Specific synthetic techniques for the selective functionalization of the 1-N position are known. Selective modification of the 1-N position is typically achieved in a multistep procedure utilizing protecting groups. First, the 1-N and 3"N positions of the aminoglycoside scaffold are blocked by forming a transition metal complex with a divalent metal ion (usually zinc, nickel, copper, or cobalt). All other positions (6'-2'- and 3-N) are then protected using standard nitrogen protecting groups (typically, these amines are protected as carbamates or acetates). With the 6'-2'- and 3-N positions protected, the transition metal complex is removed and the 1-N position is highly selectively modified. At this point, the 6'-2'- and 3-N positions are typically protected, and the only remaining free amine is the secondary 3"N amine, which is slower to react than the 1-N amine in typical acylation or alkylation reactions.

[0007] In contrast, selective functionalization of the 6'-N position remains a challenging problem. The 6'-N position is the most reactive position under various reaction conditions, and conventional methods rely on this relatively high reactivity to functionalize or protect the 6'-N amine. However, the reactivity difference between the 6'-N and other positions (especially the 2'-, 3-, and 1-N) is not significant. As a result, attempts to directly functionalize the 6'-N position are complicated by the formation of isomeric by-products and over-reacted by-products (di- or tri-functionalized aminoglycoside derivatives). The formation of high amounts of by-products is discussed in U.S. Patent Nos. 8,383,596, 8,822,424, 9,266,919, 9,688,711, and U.S. Publication No. 2012-02. The production of 6'-N-functionalized aminoglycoside derivatives such as those described in US Pat. No. 14759 requires the implementation of lengthy and costly purification procedures. To accelerate the drug discovery and development process, new methods for synthesizing aminoglycoside antibiotics are needed to provide a range of compounds that are potentially new agents for the treatment of bacterial infections. The present disclosure fulfills these needs and may provide further related advantages. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] U.S. Patent No. 8,383,596 [Patent Document 2] U.S. Patent No. 8,822,424 [Patent Document 3] U.S. Patent No. 9,266,919 [Patent Document 4] U.S. Patent No. 9,688,711 [Patent Document 5] U.S. Patent Application Publication No. 2012-0214759 Summary of the Invention

[0009] Briefly, the present disclosure relates to novel methods for preparing antibacterial aminoglycoside compounds, as well as novel intermediates and crystalline forms of certain intermediates used in the novel methods.

[0010] The present disclosure provides processes for preparing compounds of formula (9), including plazomycin, that are scalable, reproducible on a commercial scale, and have good yields. These processes include reactions that can provide novel intermediate compounds obtained through experimentation and development of new combinations of reaction conditions. The processes can also include crystallization of certain intermediates. Crystallization of these certain intermediates can unexpectedly contribute to improved purification (e.g., lower impurities) and simplify purification compared to traditional purification methods.

[0011] One aspect of the present disclosure is a process for preparing a compound of formula (2), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, comprising: (a) reacting a compound of formula (1): [ka] (1) or an enantiomer thereof or a diastereomer thereof is contacted with 1-{[(p-nitrobenzyl)oxy]carbonyl}-1H-benzotriazole (PNZ-Bt) to produce a compound of formula (2): [ka] (2) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, wherein [ka] is a single or double bond, and R 1 is H or C1-C3 alkyl, and R 2 is H or C1-C3 alkyl, and R 3 is H or C1-C3 alkyl. In certain such embodiments, step (a) is carried out in the presence of a solvent selected from the group consisting of dichloromethane, methanol, and combinations thereof. In some embodiments, PNZ-Bt is present in about 1.0 to 1.2 molar equivalents relative to the compound of Formula (1) or its enantiomer or diastereomer.

[0012] In some embodiments above or below, [ka] is a single bond or a double bond. In certain embodiments above or below, [ka] In other embodiments above or below, [ka] is a double bond. In some embodiments above or below, R 1 , R 2 , or R 3 is H.

[0013] Another aspect of the present disclosure is the step (b1) or (b2): (b1)R 1 , R 2 , and R 3 is H, contacting a compound of formula (2) with a Boc protecting group reagent to provide a compound of formula (3): [ka] (3) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof; or (b2) obtaining R 1 , R 2 , or R 3 are independently C1-C3 alkyl, the process further comprising the step of first removing the C1-C3 alkyl and then contacting the compound of Formula (2), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, with a Boc protecting group reagent to obtain a compound of Formula (3), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. In certain such embodiments, the Boc protecting group reagent is BocO or Boc-ONb. In some embodiments, step (b1) or (b2) is performed in the presence of a Lewis acid. In certain such embodiments, the Lewis acid is Zn(OAc)2, ZnCl2, or Zn(OPiv)2. In some embodiments, the Lewis acid comprises copper ions or nickel ions. In some embodiments, step (b1) or (b2) is performed in the presence of triethylamine. In certain embodiments, step (b1) or (b2) is performed in the presence of methanol.

[0014] One aspect of the present disclosure is (c) a compound of formula (3), or a salt or solvate thereof, or its enantiomers or diastereomers, [ka] to produce a compound of formula (4): [ka] (4) or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. In certain such embodiments, step (c) is carried out in the presence of an activating reagent and a peptide coupling reagent. In certain such embodiments, the activating reagent is HOBt. In certain such embodiments, the activating reagent is [ka] In some embodiments, the peptide coupling reagent is EDAC or PyBOP. In certain such embodiments, the peptide coupling reagent is [ka] It is present in an amount of about 1.0 to 1.4 molar equivalents relative to the

[0015] In some embodiments, step (c) is carried out under acidic conditions. In certain such embodiments, the acidic conditions are at a pH of about 4 to 7. In certain such embodiments, the acidic conditions are at a pH of about 5.

[0016] One aspect of the present disclosure relates to a process further comprising preparing a crystalline form of a compound of formula (4), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. In some embodiments, the process further comprises isolating the compound of formula (4), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0017] Another aspect of the present disclosure is (d) contacting a compound of formula (4), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, with a Boc protecting group reagent to produce a compound of formula (5): [ka] (5) or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. In certain such embodiments, the Boc protecting group reagent is BocO. In some embodiments, step (d) is performed in the presence of an alcohol. In certain such embodiments, the alcohol is methanol. In some embodiments, step (d) is performed at a temperature of up to about 60° C.

[0018] One aspect of the present disclosure is (e) contacting a compound of formula (5), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, with a PNZ deprotection reagent to produce a compound of formula (6): [ka] (6) or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. In certain such embodiments, the PNZ deprotecting reagent is sodium dithionite.

[0019] Another aspect of the present disclosure relates to a process further comprising preparing a crystalline form of a compound of formula (6), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. In some embodiments, the process further comprises isolating the compound of formula (6), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0020] In some embodiments, the process comprises (f) reacting a compound of formula (6), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, with [ka] (In the formula, LG 1 is a leaving group) to produce a compound of formula (7): [ka] (7) or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. In certain such embodiments, the leaving group is iodo. In some embodiments, [ka] is present in about 1.0 to 1.5 molar equivalents relative to the compound of Formula (6). In some embodiments, step (f) is carried out under substantially water-free conditions. In certain embodiments, step (f) is carried out in the presence of a solvent selected from the group consisting of acetonitrile, acetone, and combinations thereof. In some embodiments, step (f) is carried out in the presence of NaHCO. In certain embodiments, step (f) is carried out at a temperature of about 30° C. to 40° C. In some embodiments, step (f) further comprises adding 1,4-diazabicyclo[2.2.2]octane (DABCO) to the reaction mixture.

[0021] One aspect of the present disclosure relates to a process further comprising preparing a crystalline form of a compound of formula (7), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. Another aspect of the present disclosure relates to a process further comprising isolating the compound of formula (7), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0022] Another aspect of the present disclosure is (g) contacting a compound of formula (7), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, with a Boc removal reagent to produce a compound of formula (8): [ka] (8) or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. In some embodiments of step (g), the Boc removal reagent is TFA, thereby obtaining a TFA salt of the compound of formula (8), or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. In some embodiments, the process further comprises removing the TFA salt to obtain the compound of formula (8), or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0023] One aspect of the present disclosure relates to a process further comprising (h) salt formation with an acid to obtain a salt of the compound of formula (8) or a solvate thereof or an enantiomer thereof or a diastereomer thereof. In some embodiments, the acid in step (h) is sulfuric acid, thereby obtaining a sulfate salt of the compound of formula (9): [ka] or a solvate thereof, an enantiomer thereof, or a diastereomer thereof (wherein x is 1 to 5).

[0024] In some embodiments of any of the following or foregoing, the stereochemistry at carbon atoms 1, 3, 4, 5, 6, 1′, 2′, 1″, 2″, 3″, and 4″ in formulas (1)-(3) is shown as formula (X), wherein: [ka] indicates the point of attachment to a hydrogen or moiety: [ka] (X).

[0025] In some embodiments of any of the following or foregoing, the stereochemistry at carbon atoms 1, 3, 4, 5, 6, 1′, 2′, 1″, 2″, 3″, 4″, and 1-z in formulas (4)-(9) is shown as in formula (Y), wherein: [ka] indicates the point of attachment to a hydrogen or moiety: [ka] (Y).

[0026] One aspect of the present disclosure is a compound of formula (5): [ka] (5) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, the process comprising: (a) reacting a compound of formula (4): [ka] (4) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, with a Boc protecting group reagent, wherein [ka] is a single bond or a double bond. In some embodiments, the compound of formula (4), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, is a compound of formula (3): [ka] (3) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, [ka] It is prepared by contacting with

[0027] In another embodiment, the compound of formula (3), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, is (b1) a compound of formula (2a): [ka] (2a) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof is contacted with a Boc protecting group reagent, or (b2) a compound of formula (2): [ka] (2) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, by removing C1-C3 alkyl (wherein R 1 is H or C1-C3 alkyl, and R 2 is H or C1-C3 alkyl, and R 3 is H or C1-C3 alkyl, and R 1 , R 2 , or R 3 wherein one or more of is independently C1-C3 alkyl), and then contacting the compound of formula (2) with a Boc protecting group reagent.

[0028] In some embodiments, the compound of formula (2), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, is a compound of formula (1): [ka] (1) or its enantiomer or diastereomer with 1-{[(p-nitrobenzyl)oxy]carbonyl}-1H-benzotriazole (PNZ-Bt). In certain embodiments, the Boc protecting group reagent in step (a), (b1), or (b2) is BocO. In some embodiments, step (a), (b1), or (b2) is performed in the presence of an alcohol. In certain such embodiments, the alcohol is methanol. In some embodiments, step (a), (b1), or (b2) is performed at a temperature of up to about 60° C.

[0029] One aspect of the present disclosure is a compound of formula (7): [ka] (7) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, the process comprising: (f) a compound of formula (6): [ka] (6) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, [ka] wherein LG 1 is a leaving group, [ka] is a single bond or a double bond. In certain such embodiments, the leaving group is iodo. In some embodiments, [ka] is present in about 1.0 to 1.5 molar equivalents relative to the compound of Formula (6). In some embodiments, step (f) is carried out under substantially water-free conditions. In certain embodiments, step (f) is carried out in the presence of a solvent selected from the group consisting of acetonitrile, acetone, and combinations thereof. In some embodiments, step (f) is carried out in the presence of NaHCO3. In some embodiments, step (f) is carried out at a temperature of about 30°C to 40°C. In some embodiments, step (f) further comprises adding 1,4-diazabicyclo[2.2.2]octane (DABCO) to the reaction mixture.

[0030] Another aspect of the present disclosure is a compound of formula (6), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, which is a compound of formula (5): [ka] (5) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, with a PNZ deprotecting reagent.

[0031] One aspect of the present disclosure is a compound of formula (4): [ka] (4) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof. In certain such embodiments, the compound of formula (4) has the following formula: [ka] (4a), or a salt or solvate thereof.

[0032] Another aspect of the present disclosure relates to crystalline tert-butyl ((2S,3R)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-6-(((((4-nitrobenzyl)oxy)carbonyl)amino)methyl)-3,4-dihydro-2H-pyran-3-yl)carbamate, Formula (4a), or a solvate thereof.

[0033] One aspect of the present disclosure is a crystalline tert-butyl ((2S,3R)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-6-(((((4-nitrobenzyl)oxy)carbonyl)amino)methyl)-3,4-dihydro-2H-pyran-3-yl)carbamate, formula (4a): or a solvate thereof, comprising: (a) treating a compound of formula (4a) or a salt thereof or a solvate thereof with acetonitrile to form a solution; (b) heating the solution from step (a); (c) adding water to the heated solution of step (b); (d) cooling the solution from step (c); (e) charging the solution from step (d) with seed crystals; (f) isolating the resulting solid to obtain crystalline Formula (4a) or a solvate thereof.

[0034] Another aspect of the present disclosure relates to crystalline ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a), or a solvate thereof.

[0035] One aspect of the present disclosure is a process for preparing crystalline tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, formula (6a), or a solvate thereof, comprising: (a) treating a compound of formula (6) or a salt or solvate thereof with isopropyl acetate (IPAc) to form a solution; (b) adding water to the solution of step (a) to form a mixture; (c) adding dichloromethane to the mixture from step (b) to form a mixture; (d) seeding the mixture from step (c); (e) isolating the resulting solid to obtain crystalline Formula (6a) or a solvate thereof. In certain such embodiments, step (d) is carried out at a low temperature.

[0036] Another aspect of the present disclosure is a compound of formula (7): [ka] In certain such embodiments, the compound of formula (7) has the formula: [ka] (7a) or a salt or solvate thereof.

[0037] One aspect of the present disclosure relates to crystalline tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (7a), or a solvate thereof.

[0038] Another aspect of the present disclosure is a process for preparing crystalline tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, formula (7a), or a solvate thereof, comprising: (a) treating a compound of formula (7a) or a salt or solvate thereof with isopropyl acetate (IPAc) to form a solution; (b) adding acetonitrile to the solution of step (a) to form a mixture; (c) seeding the mixture from step (b); (d) isolating the resulting solid to obtain crystalline Formula (7a) or a solvate thereof.

[0039] Details of the present disclosure are described in the accompanying description below. Although methods and materials similar or equivalent to those described herein can be used in practicing or testing the present disclosure, exemplary methods and materials are described here. Other features, objects, and advantages of the present disclosure will be apparent from the description and claims. In this specification and the appended claims, the singular forms "a," "an," and "the" include the plural unless the context clearly dictates otherwise. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. All patents and publications cited herein are incorporated herein by reference in their entirety.

[0040] Each embodiment described herein may be used alone or in combination with any one or more of the other embodiments. [Brief explanation of the drawings]

[0041] Various aspects of the present disclosure will be illustrated by reference to the accompanying drawings.

[0042] [Figure 1] 1 shows the XRPD spectrum of compound 4a. [Figure 2] 1 shows the TGA profile of compound 4a. [Figure 3] 1 shows the DSC profile of compound 4a. [Figure 4] 1 shows the XRPD spectrum of compound 6a. [Figure 5] 1 shows the TGA profile of compound 6a. [Figure 6] 1 shows the DSC profile of compound 6a. [Figure 7] 1 shows the XRPD spectrum of compound 7a. [Figure 8] 1 shows the TGA profile of compound 7a. [Figure 9] 1 shows the DSC profile of compound 7a. DETAILED DESCRIPTION OF THE INVENTION

[0043] The present disclosure relates to novel methods for preparing antibacterial aminoglycoside compounds, as well as intermediates and particular crystalline forms of certain intermediates useful in such methods.

[0044] As explained above, the present disclosure provides a process for preparing compounds of formula (9), including plazomycin sulfate, that is commercially scalable, reproducible, and has good yields. The process involves a combination of reactions and conditions that can provide certain novel intermediate compounds. In certain embodiments, the process also involves crystallization of certain intermediates, which surprisingly aids in the purification process (e.g., by removing impurities, thereby reducing impurity levels), thus providing easier purification compared to conventional purification processes.

[0045] In one aspect, the present disclosure provides a compound of formula (2): [ka] (2) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof (wherein [ka] is a single or double bond, and R 1 is H or C1-C3 alkyl, and R 2 is H or C1-C3 alkyl, and R 3 is H or C1-C3 alkyl.

[0046] In another aspect, the present disclosure provides a compound of formula (3): [ka] (3) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof (wherein [ka] is a single or double bond).

[0047] In one aspect, the present disclosure provides a compound of formula (4): [ka] (4) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof (wherein [ka] is a single or double bond).

[0048] In another aspect, the present disclosure provides a compound of formula (5): [ka] (5) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof (wherein [ka] is a single or double bond).

[0049] In one aspect, the present disclosure provides a compound of formula (6): [ka] (6) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof (wherein [ka] is a single or double bond).

[0050] In another aspect, the present disclosure provides a compound of formula (7): [ka] (7) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof (wherein [ka] is a single or double bond).

[0051] In some embodiments, the present disclosure provides a compound of formula (8): [ka] (8) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof (wherein [ka] is a single or double bond).

[0052] In another aspect, the present disclosure provides a sulfate salt of a compound of formula (9): [ka] or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, wherein x is 1 to 5, [ka] is a single or double bond).

[0053] In some embodiments, the stereochemistry at carbon atoms 1, 3, 4, 5, 6, 1′, 2′, 1″, 2″, 3″, and 4″ in formulas (1)-(3) is shown as in formula (X), wherein: [ka] indicates the point of attachment to a hydrogen or moiety: [ka] (X).

[0054] In some embodiments, the stereochemistry at carbon atoms 1, 3, 4, 5, 6, 1′, 2′, 1″, 2″, 3″, 4″, and 1-z in formulas (4)-(9) is shown as in formula (Y), wherein: [ka] indicates the point of attachment to a hydrogen or moiety: [ka] (Y).

[0055] In one aspect, the present disclosure provides a compound of formula (4): [ka] (4) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof.

[0056] In some embodiments, the compound of formula (4): [ka] (4a) or a salt or solvate thereof.

[0057] In some embodiments, the present disclosure also relates to crystalline tert-butyl ((2S,3R)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-6-(((((4-nitrobenzyl)oxy)carbonyl)amino)methyl)-3,4-dihydro-2H-pyran-3-yl)carbamate, Formula (4a), or a solvate thereof.

[0058] In some embodiments, the present disclosure also provides crystalline tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, formula (6a): [ka] (6a) or a solvate thereof.

[0059] In one aspect, the present disclosure provides a compound of formula (7): [ka] It relates to a salt thereof, a solvate thereof, an enantiomer thereof or a diastereomer thereof.

[0060] In some embodiments, the compound of formula (7) has the formula: [ka] (7a) or a salt or solvate thereof.

[0061] In some embodiments, the present disclosure relates to crystalline tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (7a), or a solvate thereof.

[0062] Terms and Abbreviations As used in this disclosure, the articles "a" and "an" can refer to one or to more than one (i.e., to at least one) of the grammatical subject of the article. By way of example, "an element" means one element or more than one element.

[0063] As used in this disclosure, "and / or" can mean either "and" or "or" unless otherwise indicated.

[0064] As used herein, [ka] may refer to a single or double bond.

[0065] "Alkyl" can refer to a straight-chain or branched-chain saturated hydrocarbon. A C1-C3 alkyl group contains 1 to 3 carbon atoms. Examples of C1-C3 alkyl groups include, but are not limited to, methyl, ethyl, and propyl.

[0066] A "Boc protecting group reagent" may refer to a reagent that can be used to attach a Boc protecting group to an amine group. Examples of Boc protecting group reagents include, but are not limited to, Boc anhydride (BocO), N-tert-butoxycarbonylimidazole, 2-(tert-butoxycarbonyloxyimino)-2-phenylacetonitrile, 2-(tert-butoxycarbonylthio)-4,6-dimethylpyrimidine, 1-tert-butoxycarbonyl-1,2,4-triazole, tert-butylphenyl carbonate, N-(tert-butoxycarbonyloxy)phthalimide, tert-butyl 2,4,5-trichlorophenyl carbonate, and tert-butyl ((4R,7S)-1,3-dioxo-1,3,3a,4,7,7a-hexahydro-2H-4,7-methanoisoindol-2-yl)carbonate (Boc-ONb).

[0067] "Boc removal reagent" may refer to a reagent that can be used to cleave a Boc protecting group on an amine group. Examples of Boc removal reagents include, but are not limited to, TFA, aqueous phosphoric acid, methanesulfonic acid (MSA or MsOH), SnCl, HCl / dioxane, and HCl / MeOH. Further examples of Boc removal reagents include HCl, HSO, and PTSA (p-toluenesulfonic acid or tosylic acid).

[0068] A "Lewis acid" may refer to a compound or ionic species that can accept an electron pair from a donor compound. Examples of Lewis acids include, but are not limited to, Zn(OAc)2, ZnCl2, and Zn(OPiv)2. Additionally, other metal cations, such as copper and nickel cations, can act as Lewis acids.

[0069] "PNZ protecting group reagent" can refer to a reagent that can be used to attach a p-nitrobenzyloxycarbonyl protecting group to an amine group. Examples of PNZ protecting group reagents include, but are not limited to, 1-{[(p-nitrobenzyl)oxy]carbonyl}-1H-benzotriazole and 4-nitrobenzyl 1H-benzo[d]imidazole-1-carboxylate.

[0070] The term "1-{[(p-nitrobenzyl)oxy]carbonyl}-1H-benzotriazole" or "PNZ-Bt" may refer to the formula: [ka]

[0071] The term "4-nitrobenzyl 1H-benzo[d]imidazole-1-carboxylate" may refer to the formula: [ka]

[0072] "PNZ deprotection reagent" can refer to a reagent that can be used to cleave a p-nitrobenzyloxycarbonyl protecting group on an amine group. Examples of PNZ deprotection agents include, but are not limited to, sodium dithionite, and hydrogenation with H and Pd / C or PtO.

[0073] The term "protecting group" as used herein may refer to a labile chemical moiety known in the art for protecting reactive groups, including but not limited to hydroxyl and amino groups, from undesired reactions during synthetic procedures. Hydroxyl and amino groups protected with a protecting group are referred to herein as "protected hydroxyl groups" and "protected amino groups," respectively. Protecting groups can typically be used selectively and / or orthogonally to protect sites during reactions at other reactive sites and then removed to leave the original unprotected group or available for further reactions. Protecting groups known in the art are generally described in Greene and Wuts, Protective Groups in Organic Synthesis, 3rd Edition, John Wiley & Sons, New York (1999). Groups can be selectively incorporated into the aminoglycosides described herein as precursors. For example, an amino group can be placed in the compounds described herein as an azide group, which can be chemically converted to an amino group at a desired point in the synthesis. Generally, the groups are protected or present as precursors that are inert to reactions that modify other regions of the parent molecule in order to be converted to the final group at the appropriate time. Further representative protecting or precursor groups are described in Agrawal, et al., Protocols for Oligonucleotide Conjugates, Eds., Humana Press; New Jersey, 1994; Vol. 26 pp. 1-72.Examples of "hydroxyl protecting groups" include, but are not limited to, t-butyl, t-butoxymethyl, methoxymethyl, tetrahydropyranyl, 1-ethoxyethyl, 1-(2-chloroethoxy)ethyl, 2-trimethylsilylethyl, p-chlorophenyl, 2,4-dinitrophenyl, benzyl, 2,6-dichlorobenzyl, diphenylmethyl, p-nitrobenzyl, triphenylmethyl, trimethylsilyl, triethylsilyl, t-butyldimethylsilyl, t-butyldiphenylsilyl (TBDPS), triphenylsilyl, benzoylformate, acetate, chloroacetate, trichloroacetate, trifluoroacetate, pivalate, benzoate, p-phenylbenzoate, 9-fluorenylmethylcarbonate, mesylate, and tosylate. Examples of "amino-protecting groups" include, but are not limited to, 2-trimethylsilylethoxycarbonyl (Teoc), 1-methyl-1-(4-biphenylyl)ethoxycarbonyl (Bpoc), t-butoxycarbonyl (Boc), allyloxycarbonyl (Alloc), 9-fluorenylmethyloxycarbonyl (Fmoc), benzyloxycarbonyl (Cbz), p-nitrobenzyloxycarbonyl (PNZ), formyl, acetyl, trihaloacetyl (e.g., trifluoroacetyl), benzoyl, nitrophenylacetyl, 2-nitrobenzenesulfonyl, phthalimide, and dithiasuccinoyl.

[0074] Preparation of compounds of formula (9) and intermediates thereof: The present disclosure provides a compound of formula (9) having the following structure: [ka] or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof (wherein [ka] is a single or double bond, and x is 1 to 5).

[0075] In some embodiments, the compound of formula (9) is plazomycin sulfate, having the structure: [ka] or a solvate thereof, wherein x is 1 to 5.

[0076] Plazomicin sulfate may also be referred to as (2"R,3"R,4"R,5"R)-2"-[(1S,2S,3R,4S,6R)-4-amino-6-[(2'"S)-4'"-amino-2'"-hydroxybutanamido)amino]-3-[(2'S,3'R)-3'-amino-6'-((2-hydroxyethylamino)methyl)-3',4'-dihydro-2H-pyran-2'-yloxy]-2-hydroxycyclohexyloxy]-5"-methyl-4"-(methylamino)tetrahydro-2H-pyran-3",5"-diol sulfate. Plazomicin is 6'-(hydroxylethyl)-1-(HABA)-sisomicin; 6'-(2-hydroxy-ethyl)-1-(4-amino-2(S)-hydroxy-butyryl)-sisomicin; (2S)-4-amino-N-[(1R,2S,3S,4R,5S)-5-amino-4-[[(2S,3R)-3-amino-6-[(2-hydroxyethylamino)methyl]-3,4-dihydro-2H-pyran-2-yl]oxy]-2-[(2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)oxan-2-yl]oxy-3-hydroxycyclohexyl]-2-hydroxybutanamide; Butanamide, 4-amino-N-[(1R,2S,3S,4R,5S)-5-amino-4-[[(2S,3R)-3-amino-3,4-dihydro-6-[[(2-hydroxyethyl)amino]methyl]-2H-pyran-2-yl]oxy]-2-[[3-deoxy-4-C-methyl-3-(methylamino)-β-L-arabinopyranosyl]oxy]-3-hydroxycyclohexyl]-2-hydroxy-, (2S)-; D-streptamine, O-2-amino-2,3,4,6-tetradeoxy-6-[(2-hydroxyethyl)amino]-aD-glycero-hex-4-enopyranosyl-(1→4)-O-[3-deoxy-4-C-methyl-3-(methylamino)-bL-arabinopyranosyl-(1→6)]-N1-[(2S)-4-amino-2-hydroxy-1-oxobutyl]-2-deoxy-; O-2-amino-2,3,4,6-tetradeoxy-6-[(2-hydroxyethyl)amino]-aD-glycero-hex-4-enopyranosyl-(1→4)-O-[3-deoxy-4-C-methyl-3-(methylamino)-bL-arabinopyranosyl-(1→6)]-N1-[(2S)-4-amino-2-hydroxy-1-oxobutyl]-2-deoxy-D-streptamine; and (2S)-4-Amino-N-[(1R,2S,3S,4R,5S)-5-amino-4-{[(2S,3R)-3-amino-6-{[(2-hydroxyethyl)amino]methyl}-3,4-dihydro-2H-pyran-2-yl]oxy}-2-{[3-deoxy-4- It may also be referred to as C-methyl-3-(methylamino)-β-L-arabinopyranosyl]oxy}-3-hydroxycyclohexyl]-2-hydroxybutanamide.

[0077] The conventional atomic numbering of plazomicin is shown below: [ka] .

[0078] A process for preparing compounds of formula (9) and certain intermediates obtained in the preparation of compounds of formula (9) is illustrated in Scheme 1 below and described in more detail herein. Scheme 1 [ka]

[0079] As noted above, the present disclosure provides a process for preparing compounds of formula (9), including plazomycin sulfate, that is not only scalable to commercial quantities, but also reliably reproducible from batch to batch on such a commercial scale, and in good yields. The synthetic methods and purification processes described herein outline a scalable and economically advantageous process for preparing the compound of formula (9) and its intermediates, which does not rely on expensive and / or elaborate steps during preparation, making the method particularly suitable for large-scale production of antibiotics.

[0080] The process involves a combination of reaction conditions and steps to obtain a novel intermediate compound. For example, selective functionalization of the 6'-N position has been challenging. However, as described in this disclosure, the reaction of the compound of formula (6) with the compound of formula (7) described herein unexpectedly yielded a mono-alkylated product, whereas under normal circumstances, such a reaction would be expected to result in over-alkylation.

[0081] The process may also include crystallization of certain intermediates. As described herein, crystallization of certain intermediates aids in the purification process (e.g., reduces impurities) and simplifies the purification process compared to conventional purification processes. For example, conventional purification processes include precipitation, which can provide isolated compounds of poorer purity and / or specificity. The precipitation step can also reduce yields and result in higher batch-to-batch variability in impurity levels. As described herein, crystallization can act to remove impurities. Furthermore, although significant effort is required to initially determine appropriate crystallization conditions, once the crystallization conditions are determined, the process is simple and reproducible. For example, crystal samples can be recovered from a previous round of crystallization to use as seeds for subsequent crystallizations. As described below, compounds of formulas (4), (6), and (7) can be crystallized.

[0082] The compounds and processes for producing the compounds described herein may include salts of the compounds described herein. Representative salts include, for example, water-soluble and water-insoluble salts, such as acetate, amsonate (4,4-diaminostilbene-2,2-disulfonate), benzenesulfonate, benzoate, bicarbonate, bisulfate, bitartrate, borate, bromide, butyrate, calcium, calcium edetate, camsylate, carbonate, chloride, citrate, clavulanate, dihydrochloride, edetate, edisylate, estolate, esylate, fumarate, gluceptate, gluconate, glutamate, glycollylarsanilate, hexafluorophosphate, hexylresorcinate, hydrabamine, hydrobromide, hydrochloride, hydroxynaphthoate, iodide, sethionate, lactate, lactobionate, and lauric acid salts. Salts of methylglucamine include, but are not limited to, methyl acetate, magnesium, malate, maleate, mandelate, mesylate, methyl bromide, methyl nitrate, methyl sulfate, mucate, napsylate, nitrate, N-methylglucamine ammonium salt, 3-hydroxy-2-naphthoate, oleate, oxalate, palmitate, pamoate (1,1-methene-bis-2-hydroxy-3-naphthoate, einbonate), pantothenate, phosphate / diphosphate, picrate, polygalacturonate, propionate, p-toluenesulfonate, salicylate, stearate, diacetate, succinate, sulfate, sulfosalicylate, suramate, tannate, tartrate, teoclate, tosylate, triethiodiphosphate, and valerate.

[0083] Salts may also include acid addition salts, which retain the biological effectiveness and properties of the free base and which are not biologically or otherwise undesirable, and which are salts of inorganic acids, including, but not limited to, hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like, as well as acetic acid, 2,2-dichloroacetic acid, adipic acid, alginic acid, ascorbic acid, aspartic acid, benzenesulfonic acid, benzoic acid, 4-acetamidobenzoic acid, camphoric acid, camphor-10-sulfonic acid, capric acid, caproic acid, caprylic acid, carbonic acid, cinnamic acid, citric acid, cyclamic acid, dodecylsulfuric acid, ethane-1,2-disulfonic acid, ethanesulfonic acid, 2-hydroxyethanesulfonic acid, formic acid, fumaric acid, galactaric acid, gentisic acid, glucoheptonic acid. The term "cobalamin" may refer to a salt formed with an organic acid, including, but not limited to, gluconic acid, glucuronic acid, glutamic acid, glutaric acid, 2-oxo-glutaric acid, glycerophosphoric acid, glycolic acid, hippuric acid, isobutyric acid, lactic acid, lactobionic acid, lauric acid, maleic acid, malic acid, malonic acid, mandelic acid, methanesulfonic acid, mucic acid, naphthalene-1,5-disulfonic acid, naphthalene-2-sulfonic acid, 1-hydroxy-2-naphthoic acid, nicotinic acid, oleic acid, orotic acid, oxalic acid, palmitic acid, pamoic acid, propionic acid, pyroglutamic acid, pyruvic acid, salicylic acid, 4-aminosalicylic acid, sebacic acid, stearic acid, succinic acid, tartaric acid, thiocyanic acid, p-toluenesulfonic acid, trifluoroacetic acid, undecylenic acid, and the like.

[0084] The compounds and manufacturing processes of the compounds described herein may include solvates of the compounds described herein. The term "solvate" may refer to a complex of variable stoichiometry formed by a solute and a solvent. For the purposes of this disclosure, such a solvent may not interfere with the biological activity of the solute. Examples of suitable solvents include, but are not limited to, water, MeOH, EtOH, and AcOH. Solvates in which water is the solvent molecule are typically referred to as hydrates. Hydrates may include compositions containing stoichiometric amounts of water and compositions containing variable amounts of water.

[0085] Those skilled in the art will recognize whether a stereocenter exists in any of the compounds described herein and the processes for making the compounds. Thus, the present disclosure includes both possible stereoisomers (unless the stereochemistry is specified herein), including not only racemates but also individual enantiomers and / or diastereomers. Furthermore, those skilled in the art will recognize whether positional or geometric isomers exist for the compounds described herein. Thus, the present disclosure includes all possible positional or geometric isomers (unless the isomer is specified herein). In the structures shown herein, if the stereochemistry of any particular chiral atom is not specified, or if a geometric or positional isomer is not specified, all stereoisomers and geometric or positional isomers are contemplated and included in the compounds and processes for making the compounds described herein. If a stereochemistry or a geometric or positional isomer is specified, then that stereochemistry or geometric or positional isomer is so specified and defined.

[0086] The term "stereoisomer" can refer to a set of compounds that have the same number and types of atoms and share the same bond connections between those atoms, but differ in three-dimensional structure. The term "stereoisomer" can refer to any member of this set of compounds. For example, a stereoisomer can be an enantiomer or a diastereomer. The compounds and processes for making the compounds described herein can include stereoisomers.

[0087] The term "enantiomer" may refer to a pair of stereoisomers that are non-superimposable mirror images of each other. The term "enantiomer" may refer to a single member of the stereoisomer pair. The term "racemic" may refer to a 1:1 mixture of a pair of enantiomers. The compounds and processes for making the compounds described herein may contain enantiomers. Each compound disclosed herein may include all enantiomers that fit the general structure of the compound (unless an enantiomer is specified herein). The compounds may be in racemic or enantiomerically pure form (unless the stereochemistry is specified herein) or any other form with respect to stereochemistry. In some embodiments, the compound is the (S)-enantiomer. In other embodiments, the compound is the (R)-enantiomer. In still other embodiments, the compound is the (+) or (-) enantiomer. In some embodiments, the compounds described herein may be enriched to provide predominantly one enantiomer of the compounds described herein. An enantiomerically enriched mixture may, for example, contain at least one enantiomer of the compound described herein. The compound may contain at least 60 mol percent, or more preferably at least 75, 80, 85, 90, 95, 96, 97, 98, 99, 99, 99.5, or even 100 mol percent, of one enantiomer. In some embodiments, a compound described herein enriched in one enantiomer may be substantially free of the other enantiomer, where substantially free means that the substance in question constitutes less than 10%, or less than 5%, or less than 4%, or less than 3%, or less than 2%, or less than 1% of the amount of the other enantiomer in, for example, the compound mixture. For example, if a compound mixture contains 98 g of a first enantiomer and 2 g of a second enantiomer, it would be said to contain 98 mol% of the first enantiomer and only 2 mol% of the second enantiomer.

[0088] The term "diastereomer" may refer to a set of stereoisomers that cannot be superimposed by rotation around a single bond. For example, compounds containing cis and trans double bonds, endo and exo substitution in bicyclic ring systems, and multiple stereogenic centers with different relative configurations are considered diastereomers. The term "diastereomer" may refer to any member of this set of compounds. In some examples provided, synthetic routes may produce single diastereomers or mixtures of diastereomers. The compounds and processes for producing the compounds described herein may include diastereomers. In some embodiments, the compounds described herein may be enriched to provide predominantly one diastereomer of the compounds disclosed herein. A diastereomerically enriched mixture may contain, for example, at least 60 mol percent, or more preferably at least 75, 99, 95, 96, 97, 98, 99, or 100 mol percent of one diastereomer.

[0089] Furthermore, the compounds and manufacturing processes of the compounds described herein include all geometric and positional isomers.For example, when the compounds described herein incorporate double bonds or fused rings, both cis and trans forms and mixtures can be encompassed within the scope of the present disclosure.When the compound contains a double bond, the substituent can be in E or Z configuration (unless otherwise specified herein).When the compound contains a disubstituted cycloalkyl, the cycloalkyl substituent can have cis or trans configuration (unless otherwise specified herein).

[0090] The compounds described herein may further include all isotopically labeled compounds. An "isotope" or "radiolabeled" compound is a compound in which one or more atoms are replaced or substituted by an atom having an atomic mass or mass number different from the atomic mass or mass number typically found in nature (i.e., naturally occurring). For example, in some embodiments, in the compounds described herein, a hydrogen atom may be replaced or substituted by one or more deuterium or tritium atoms. Certain isotopically labeled compounds of the present disclosure, for example, compounds incorporating a radioisotope, may be useful in drug and / or substrate tissue distribution studies. The radioisotope tritium, i.e., 3 H, and carbon-14, i.e. 14 C are particularly useful for this purpose in light of their ease of incorporation and existing means of detection. Heavier isotopes such as deuterium, i.e., 2 Substitution with H may offer certain therapeutic advantages due to greater metabolic stability, for example, increased in vivo half-life or reduced dosage requirements, and therefore may be preferred in some circumstances. Suitable isotopes that may be incorporated into the compounds described herein include: 2 H (also written as D for deuterium), 3 H (also written as T for tritium), 11 C. 13 C. 14 C. 13 N, 15 N, 15 O. 17 O. 18 O. 18 F, 35 S, 36 Cl, 82 Br, 75 Br, 76 Br, 77 Br, 123 I, 124 I, 125 I, and 131 Positron-emitting isotopes, such as, but not limited to, I. 11 C. 18 F, 15 O, and 13Substitution at N may be useful in positron emission tomography (PET) studies.

[0091] Compounds of any of the formulas described herein can be prepared by art-known methods of organic synthesis, as illustrated in part by the following synthetic schemes and examples, in conjunction with the guidance provided herein. In the schemes described below, it is understood that protecting groups for sensitive or reactive groups can be used as necessary in accordance with general principles or chemistry following the guidance provided herein. Protecting groups can be manipulated according to standard methods of organic synthesis (T.W. Greene and P.G.M. Buts, "Protective Groups in Organic Synthesis," 3rd ed., Wiley, New York 1999). These groups can be removed at a convenient stage in the compound synthesis using methods that will be readily apparent to those skilled in the art based on the detailed teachings provided herein. The selected processes and reaction conditions and the order of their execution are consistent with the present disclosure.

[0092] The following Schemes 2 to 5 also illustrate the synthesis of compounds of formula (9) and intermediates thereof. Scheme 2: Synthesis of compounds of formula (4) [ka]

[0093] Scheme 2 illustrates the synthesis of a compound of formula (4), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. In Scheme 2, R 1 is H or C1-C3 alkyl, and R 2 is H or C1-C3 alkyl, and R 3 is H or C1-C3 alkyl, [ka] is a single or double bond.

[0094] Synthesis of compounds of formula (2) With continued reference to Scheme 2, in some embodiments, the reaction detailed in Scheme 2 is carried out at a temperature of up to about 60° C. A compound of Formula (1), or an enantiomer or diastereomer thereof, can be contacted with a PNZ protecting group reagent to form a compound of Formula (2), or a salt or solvate thereof, or an enantiomer or diastereomer thereof. In some embodiments, the PNZ protecting group reagent is selected from 1-{[(p-nitrobenzyl)oxy]carbonyl}-1H-benzotriazole (PNZ-Bt) and 4-nitrobenzyl 1H-benzo[d]imidazole-1-carboxylate. In some embodiments, the PNZ protecting group reagent is PNZ-Bt.

[0095] In certain such embodiments, the PNZ protecting group reagent may be present in the reaction in about 1.0 to 1.2 molar equivalents relative to the compound of Formula (1), or its enantiomer, or diastereomer. In some embodiments, the reaction between the compound of Formula (1), or its enantiomer, or diastereomer, and the PNZ protecting group reagent is carried out in a solvent such as dichloromethane, acetone, methyl methyl ether ... In certain such embodiments, the reaction may be carried out in the presence of a solvent selected from the group consisting of alcohols, and combinations thereof. In certain such embodiments, the alcohol is methanol. The presence of methanol may result in a reduction of R 1 , R 2 , and / or R 3 The selectivity of the reaction may be increased when is H. In other embodiments, the reaction between a compound of formula (1) or an enantiomer or diastereomer thereof and a PNZ protecting group reagent may be carried out in the presence of a solvent selected from the group consisting of dichloromethane, ethanol, and combinations thereof.

[0096] In some embodiments, the compound of formula (2) can be used in the next reaction without substantial purification.

[0097] In certain embodiments, R in a compound of formula (1) or an enantiomer or diastereomer thereof 1 , R2 , and R 3 is H. In certain such embodiments, the compound of formula (2) is a compound of formula (2a): [ka] (2a) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof. In certain such embodiments, [ka] is a double bond.

[0098] In some embodiments, the compound of formula (1) that is contacted with the PNZ protecting group reagent can be sisomicin free base (shown below). [ka] . In certain such embodiments, the compound of formula (2) is a compound of formula (2b): [ka] or a salt or solvate thereof.

[0099] Synthesis of compounds of formula (3) Continuing with Scheme 2, a compound of formula (3): [ka] (3) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof can be synthesized from a compound of formula (2), or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof. In certain such embodiments, [ka] is a double bond.

[0100] R1, R 2 , and R 3 When R is H, the compound of formula (2), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, may be contacted with a Boc (tert-butyloxycarbonyl) protecting group reagent to provide a compound of formula (3), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. 1 , R 2 , or R 3 are independently a C1-C3 alkyl, one or more of the C1-C3 alkyl groups may be removed and the compound of formula (2), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, may be contacted with a Boc protecting group reagent to obtain a compound of formula (3), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof.

[0101] In some embodiments, the Boc protecting group reagent is di-tert-butyl dicarbonate, N-(t-butoxycarbonyloxy)-5-norbornene-endo-2,3-dicarboximide, N-tert-butoxycarbonylimidazole, 2-(tert-butoxycarbonyloxyimino)-2-phenylacetonitrile, 2-(tert-butoxycarbonylthio)-4,6-dimethylpyrimidine, 1-tert-butoxycarbonyl-1,2,4-triazole, tert-butylphenyl carbonate, N-(tert-butoxycarbonyloxy)phthalimide, or tert-butyl 2,4,5-trichlorophenyl carbonate. In some embodiments, the Boc protecting group reagent is BocO (Boc anhydride; di-tert-butyl dicarbonate) or Boc-ONb (N-(t-butoxycarbonyloxy)-5-norbornene-endo-2,3-dicarboximide). In certain such embodiments, the Boc protecting group reagent is BocO. In certain such embodiments, the Boc protecting group reagent is Boc-ONb.

[0102] The reaction between a compound of formula (2), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, and a Boc protecting group reagent can be carried out in the presence of a Lewis acid. In certain such embodiments, the Lewis acid is Zn(OAc), ZnCl, or Zn(OPiv). Alternatively, the reaction between a compound of formula (2), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, and a Boc protecting group reagent can also be carried out in the presence of a Lewis acid containing a copper ion or a nickel ion.

[0103] Furthermore, the reaction between the compound of formula (2), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, and a Boc protecting group reagent may be carried out in the presence of an amine. In some embodiments, the amine is 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), pyridine, piperidine, 4-dimethylaminopyridine (DMAP), 2,6-lutidine, dimethylaniline, N-methylpyridone, N-diisopropylethylamine, N-methylimidazole, N-ethyldimethylamine, trimethylamine, or triethylamine. In some embodiments, the amine is triethylamine.

[0104] Furthermore, the reaction between the compound of formula (2), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, and a Boc protecting group reagent can be carried out in the presence of an alcohol. In certain such embodiments, the alcohol is methanol.

[0105] In some embodiments, the compound of formula (3) can be used in the next reaction without substantial purification.

[0106] In some embodiments, the compound of formula (3), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, is a compound of formula (3a), synthesized by contacting a compound of formula (2b), or a salt thereof, a solvate thereof, with a Boc protecting group reagent: [ka] or a salt thereof or a solvate thereof.

[0107] Synthesis of compounds of formula (4) Continuing with Scheme 2, a compound of formula (3), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, is reacted with a compound of formula (3), [ka] to produce a compound of formula (4): [ka] (4) or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. In certain such embodiments, [ka] is a double bond.

[0108] a compound of formula (3), a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof [ka] The reaction between may be carried out in the presence of an activating reagent and a peptide coupling reagent.

[0109] An activating reagent refers to a reagent that converts the carbonyl of a carboxylic acid group into one that is susceptible to nucleophilic attack. In some embodiments, the activating reagent is HATU, HOOBt, HOSu, HOAt, DMAP, BOP, PyBOP, PyBrOP, PyAOP, PyOxim, DEPBT, TBTU, HBTU, HCTU, HDMC, COMU, CDI, or HOBt. In certain such embodiments, the activating reagent is HOBt. In some embodiments, the activating reagent is [ka] It is present in an amount of about 0.05 to 1.0 molar equivalents relative to the

[0110] In some embodiments, the peptide binding reagent is DCC, EDC, DIC, WSC, EDAC, or PyBOP. In some embodiments, the peptide binding reagent is EDAC or PyBOP. In certain such embodiments, the peptide binding reagent is EDAC. In some embodiments, the peptide binding reagent is [ka] In some embodiments, the peptide coupling reagent is present in an amount of about 1.0 to 1.4 molar equivalents relative to [ka] The compound is present in an amount of about 1.0, 1.1, 1.2, 1.3, or 1.4 molar equivalents relative to the compound.

[0111] a compound of formula (3), a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof [ka] The reaction between may be carried out under acidic conditions. In certain such embodiments, the acidic conditions are at a pH of about 4 to 7. In certain such embodiments, the acidic conditions are at a pH of about 5.

[0112] a compound of formula (3), a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof [ka] The reaction between may be carried out in the presence of an alcohol. In certain such embodiments, the alcohol is methanol.

[0113] The compound of formula (4), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, can be prepared by reacting a compound of formula (3a), or a salt thereof, or a solvate thereof, [ka] A compound of formula (4a) synthesized by contacting [ka] or a salt thereof or a solvate thereof.

[0114] The present disclosure further provides processes comprising preparing a crystalline form of a compound of formula (4), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. The present disclosure also provides processes comprising isolating a compound of formula (4), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, for example, as described below in Example 1.

[0115] As described herein, certain crystallization steps under certain conditions can aid in purification by removing impurities. Furthermore, once the crystallization conditions are established, using crystallization as a means of purification can result in both better yields and reduced batch-to-batch impurity variability compared to traditional purification methods. Scheme 3: Synthesis of compounds of formula (6) [ka]

[0116] Scheme 3 shows the synthesis of a compound of formula (6), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. [ka] is a single or double bond.

[0117] Synthesis of compounds of formula (5) With continued reference to Scheme 3, a compound of formula (4), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, may be contacted with a Boc protecting group reagent to provide a compound of formula (5), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. In certain such embodiments, [ka] is a double bond.

[0118] Standard Boc protecting group reagents can be used for this transformation, including, but not limited to, N-tert-butoxycarbonylimidazole, 2-(tert-butoxycarbonyloxyimino)-2-phenylacetonitrile, 2-(tert-butoxycarbonylthio)-4,6-dimethylpyrimidine, 1-tert-butoxycarbonyl-1,2,4-triazole, tert-butylphenyl carbonate, N-(tert-butoxycarbonyloxy)phthalimide, tert-butyl 2,4,5-trichlorophenyl carbonate, BocO, and Boc-ONb. In some embodiments, the Boc protecting group reagent is BocO.

[0119] In some embodiments, the reaction between a compound of Formula (4), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, and a Boc protecting group reagent can be carried out at a temperature of up to about 60° C. In some embodiments, the reaction between a compound of Formula (4), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, and a Boc protecting group reagent can be carried out in the presence of an alcohol. In certain such embodiments, the alcohol is methanol or ethanol. In certain such embodiments, the alcohol is methanol. The use of an alcohol in the reaction between a compound of Formula (4), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, and a Boc protecting group reagent can aid in telescoping for use in the subsequent reaction.

[0120] In some embodiments, the compound of formula (5) can be used in the next reaction without substantial purification.

[0121] The compound of formula (5), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, can be synthesized by contacting a compound of formula (4a), or a salt thereof, or a solvate thereof, with a Boc protecting group reagent to give a compound of formula (5a): [ka] It may be a salt thereof or a solvate thereof.

[0122] Synthesis of the compound of formula (6) With continued reference to Scheme 3, a compound of formula (5), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, may be contacted with a PNZ deprotecting reagent to provide a compound of formula (6), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. In certain such embodiments, [ka] is a double bond.

[0123] In some embodiments, the PNZ deprotection reagent is sodium dithionite. In other embodiments, the PNZ deprotection reaction can be hydrogenation with H and a catalyst such as Pd / C or PtO. Sodium dithionite can be advantageous over deprotection reactions that require hydrogenation because it can be easier to use on a larger scale, more chemoselective, less hazardous, and does not require the use of specialized equipment.

[0124] The compound of formula (6), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, is synthesized by contacting a compound of formula (5a), or a salt thereof, or a solvate thereof, with a PNZ deprotection reagent to give a compound of formula (6a): [ka] or a salt thereof or a solvate thereof.

[0125] The present disclosure further provides a process for preparing a crystalline form of a compound of formula (6), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. The present disclosure also provides a process for preparing a crystalline form of a compound of formula (6), for example, as described below in Example 2. and isolating the compound, or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0126] Thus, as noted above, this crystallization may aid in the purification process (e.g., reduce impurities) and simplify the purification process compared to conventional purification methods, thereby providing greater reproducibility for the overall process. Scheme 4: Synthesis of compounds of formula (7) [ka]

[0127] Scheme 4 shows the synthesis of a compound of formula (7), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. [ka] is a single bond or a double bond. In some embodiments, [ka] is a double bond.

[0128] The reaction of a compound of formula (6) to a compound of formula (7) is surprising with respect to alkylation. Under normal circumstances, primary amines, such as the group on a compound of formula (6), tend to alkylate more than once. Therefore, it is surprising that a compound of formula (7) contains a secondary amine (e.g., is alkylated once with -CHCHOH). As explained below, reaction conditions, including the choice of solvent and the use of reagents to prevent over-alkylation, can result in mono-alkylation at the appropriate site.

[0129] Synthesis of the compound of formula (7) Continuing with Scheme 4, a compound of formula (6), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, is reacted with a compound of formula (6), [ka] (In the formula, LG 1 is a leaving group) to provide a compound of formula (7), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. In certain such embodiments, the leaving group is iodo, bromo, or chloro. In certain such embodiments, the leaving group is iodo. In some embodiments, [ka] is present in an amount of about 1.0 to 1.5 molar equivalents relative to the compound of formula (6).

[0130] a compound of formula (6), a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof [ka] The reaction between the compound of formula (6), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, and [ka] The reaction between (a) and (b) may be carried out in the presence of a solvent selected from the group consisting of acetonitrile, acetone, and combinations thereof. Acetone may aid in the selectivity of the reaction and promote mono-alkylation. Acetonitrile may be used to remove water by azeotropy.

[0131] In some embodiments, a compound of formula (6), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, [ka] The reaction between may be carried out in the presence of NaHCO3, lithium carbonate, sodium carbonate, potassium carbonate, cesium carbonate, sodium sulfate, DIPEA, sodium phosphate, trimethyl orthoformate, and hexamethyldisilane. In certain such embodiments, the reaction is carried out in the presence of NaHCO3. In some embodiments, the compound of formula (6), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, and [ka] The reaction between may be carried out at a temperature of about 30° C. to 40° C. In certain such embodiments, the temperature is about 35° C. Temperatures above 50° C. may result in the formation of dialkylated by-products.

[0132] a compound of formula (6), a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof [ka] The reaction between can be quenched by adding 1,4-diazabicyclo[2.2.2]octane (DABCO) to the reaction mixture. DABCO can be used to essentially stop the reaction and prevent over-alkylation. Alternatively, a compound of formula (6), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, can be reacted with [ka] The reaction between can be quenched by adding 1-propylamine, piperidine, diethylamine, N-ethyldimethylamine, triethylamine, DBU, MeOH, carbonate buffer, dimethylamine, cysteine, diethanolamine, or NaOH.

[0133] In some embodiments, the compound of formula (7), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, is a compound of formula (6a), or The salt or solvate thereof [ka] A compound of formula (7a) synthesized by contacting [ka] or a salt thereof or a solvate thereof.

[0134] The present disclosure further provides a process for preparing a crystalline form of a compound of formula (7), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. The present disclosure also provides a process comprising isolating a compound of formula (7), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, as described below, for example, in Example 3.

[0135] This crystallization may aid in the purification process (e.g., reduce impurities) and simplify purification compared to traditional purification methods. Crystallization may also act to remove impurities. Scheme 5: Synthesis of compounds of formula (9) [ka]

[0136] Scheme 5 shows the synthesis of a compound of formula (9), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. [ka] is a single bond or a double bond, and x is 1 to 5. In some embodiments, [ka] is a double bond. In some embodiments, x is 2-3.

[0137] Synthesis of the compound of formula (8) With continued reference to Scheme 5, a compound of formula (7), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, may be contacted with a Boc removal reagent to provide a compound of formula (8), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. In some embodiments, the Boc removal reagent is TFA, MsOH (methanesulfonic acid or CHSOH), PTSA (p-toluenesulfonic acid or tosylic acid), HSO, or HCl. In some embodiments, the Boc removal reagent is TFA or MsOH. In some embodiments, the Boc removal reagent is TFA, HSO, or HCl.

[0138] In some embodiments, the Boc removal reagent is TFA, thereby obtaining a TFA salt of the compound of formula (8) or a solvate thereof or an enantiomer thereof or a diastereomer thereof. TFA is typically used for this conversion because the deprotection reaction requires anhydrous conditions.

[0139] The step of removing the Boc group may result in hydrolysis of the substrate and the presence of compound (IMP-1) immediately after the reaction (eg, before any purification). [ka] (IMP-1) In certain embodiments, the step of removing the Boc group does not result in substantial hydrolysis, and the presence of compound (IMP-1) is minimized immediately after the reaction (e.g., before any purification). In certain embodiments, the presence or amount of compound (IMP-1) can be determined by HPLC. In certain embodiments, compound IMP-1 can be present in an amount of 0-7%, e.g., about 0, 0.2, 0.4, 0.6, 0.8, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, or 7%, immediately after the reaction (e.g., before any purification). When the amount of IMP-1 is 0%, this indicates that certain impurities may be present at levels below the detection level of typical analytical methods (e.g., HPLC) known and routinely used by those skilled in the art.

[0140] In certain embodiments, the acid is TFA or MsOH, and the amount of compound IMP-1 can be about 0-7% immediately after the reaction (e.g., before any purification). In some cases, the acid is TFA or MsOH, and the amount of compound IMP-1 can be about 0-2.5% immediately after the reaction (e.g., before any purification). In some cases, the acid is TFA, and the amount of compound IMP-1 can be about 0-2.5%, e.g., about 0, 0.2, 0.4, 0.6, 0.8, 1, 1.5, 2, or 2.5%, immediately after the reaction (e.g., before any purification). In some cases, the acid is MsOH, and the amount of compound IMP-1 can be about 0-2.5%, e.g., about 0.2, 0.4, 0.6, 0.8, 1, 1.5, 2, or 2.5%, immediately after the reaction (e.g., before any purification).

[0141] In some cases, the acid is HCl and the amount of compound IMP-1 can be about 0-1%, e.g., about 0, 0.2, 0.4, 0.6, 0.8, or 1%, immediately after the reaction (e.g., before any purification).

[0142] In some cases, the acid is H2SO4 and the amount of compound IMP-1 can be 0-7%, for example, about 0, 0.2, 0.4, 0.6, 0.8, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, or 7%, immediately after the reaction (e.g., before any purification).

[0143] When the compound of formula (7), or its salt, solvate, enantiomer, or diastereomer, is contacted with various Boc removal reagents, the amount of IMP-1 may vary depending on the identity of the Boc removal reagent. The table below shows the amount of IMP-1 from the reaction of the compound of formula (7), or its salt, solvate, enantiomer, or diastereomer, with various Boc removal reagents. [Table 12]

[0144] In some embodiments, the compound of formula (8) can be used in the next reaction without substantial purification.

[0145] In some embodiments, the compound of formula (8), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, is synthesized by contacting a compound of formula (7a), or a salt thereof, or a solvate thereof, with a Boc removal reagent to give a compound of formula (8a): [ka] or a solvate thereof.

[0146] Synthesis of the compound of formula (9) Salt formation with an acid may be carried out to obtain a salt of the compound of formula (8) or a solvate thereof or an enantiomer thereof or a diastereomer thereof. If the compound of formula (8) is already a salt such as a TFA salt, the salt may be removed to obtain the compound of formula (8), its solvate, its enantiomer, or diastereomer thereof. Once the thiomer or its diastereomer is obtained, different salts may be formed.

[0147] In some embodiments, the acid in the salt-forming step is sulfuric acid, thereby forming the sulfate salt of the compound of formula (9): [ka] or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof (wherein x is 1 to 5). In some embodiments, x is 2 to 3. The sulfate salt of the compound of formula (9) may have improved stability compared to other salts. In some embodiments, the compound of formula (9), or a salt thereof, a solvate thereof, or an enantiomer thereof, or a diastereomer thereof is synthesized by salt formation with a compound of formula (8a), or a salt thereof, or a solvate thereof, of plazomycin sulfate: [ka] or a solvate thereof, wherein x is 1 to 5. In some embodiments, x is 2 to 3.

[0148] Crystalline Compounds and Their Preparation and Characterization: In one embodiment, the present disclosure relates to intermediates in a synthetic process that can be used to synthesize a compound of formula (9), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. These intermediates can be in crystalline form. The present disclosure provides methods for producing crystalline intermediates in a synthetic process that can be used to synthesize a compound of formula (9), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. The crystalline intermediates of the present disclosure can be characterized by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The methods for collecting XRPD, DSC, and TGA data, as well as the properties of the crystalline intermediates of the present disclosure, are further illustrated in the following examples. Compounds 4 and 4a

[0149] In some embodiments, an intermediate in the synthesis of a compound of formula (9), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, is a compound of formula (4): [ka] (4) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof. In certain such embodiments, the compound of formula (4) is of the following formula: [ka] (4a), or a salt or solvate thereof. In certain such embodiments, the compound of Formula (4a) is crystalline tert-butyl ((2S,3R)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-6-(((((4-nitrobenzyl)oxy)carbonyl)amino)methyl)-3,4-dihydro-2H-pyran-3-yl)carbamate, or a solvate thereof.

[0150] In some embodiments, the crystalline tert-butyl ((2S,3R)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-6-(((((4-nitrobenzyl)oxy)carbonyl)amino)methyl)-3,4-dihydro-2H-pyran-3-yl)carbamate, or a solvate thereof, is characterized by an XRPD pattern having peak positions substantially in accordance with those shown in FIG. 1 .

[0151] In some embodiments, the crystalline tert-butyl ((2S,3R)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-6-(((((4-nitrobenzyl)oxy)carbonyl)amino)methyl)-3,4-dihydro-2H-pyran-3-yl)carbamate, or a solvate thereof, is characterized by the TGA trace shown in FIG. 2. In some embodiments, the crystalline tert-butyl ((2S,3R)-2-(((1R,2S,3S, 4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-6-(((((4-nitrobenzyl)oxy)carbonyl)amino)methyl)-3,4-dihydro-2H-pyran-3-yl)carbamate, or a solvate thereof, is characterized by the DSC profile of FIG. 3.

[0152] The present disclosure provides a process for preparing crystalline tert-butyl ((2S,3R)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-6-(((((4-nitrobenzyl)oxy)carbonyl)amino)methyl)-3,4-dihydro-2H-pyran-3-yl)carbamate, formula (4a), or a solvate thereof, comprising: (a) treating a compound of formula (4a) or a salt thereof or a solvate thereof with acetonitrile to form a solution; (b) heating the solution from step (a); (c) adding water to the heated solution of step (b); (d) cooling the solution from step (c); (e) charging the solution from step (d) with seed crystals; (f) isolating the resulting solid to obtain crystalline Formula (4a) or a solvate thereof.

[0153] In some embodiments for preparing crystalline tert-butyl ((2S,3R)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-6-(((((4-nitrobenzyl)oxy)carbonyl)amino)methyl)-3,4-dihydro-2H-pyran-3-yl)carbamate, acetonitrile with 1.5% deionized (DI) water at 75±3° C. with seeding followed by cooling may be used for crystallization. Additionally, crystallization can be carried out at 65±3° C. or 70±3° C., followed by cooling. In some embodiments, 1-propanol, with or without deionized (DI) water, can be used instead of acetonitrile for the crystallization of tert-butyl ((2S,3R)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-6-(((((4-nitrobenzyl)oxy)carbonyl)amino)methyl)-3,4-dihydro-2H-pyran-3-yl)carbamate. The crystallization conditions tested are summarized in Example 1 and Table 5.

[0154] compound 6a In some embodiments, an intermediate in the synthesis of a compound of formula (9), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, is a compound of formula (6a): [ka] or a salt or solvate thereof. In certain such embodiments, the present disclosure provides crystalline tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a), or a solvate thereof.

[0155] In some embodiments, the crystalline tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, or a solvate thereof, is characterized by an XRPD pattern having peak positions substantially in accordance with those shown in FIG. 4 and Table 1. In some embodiments, there is a variation of about ±0.2 degrees 2θ for the diffraction angles in the XRPD patterns, for example, as shown in Table 1. [Table 1]

[0156] In certain embodiments, crystalline tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydro Xybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, or a solvate thereof, is characterized by one or more 2θ values ​​at about 6.10, 10.66, 12.17, 17.65, and 18.55 degrees in X-ray powder diffraction, where there is a variation of about ±0.2 degrees 2θ relative to the diffraction angles in the XRPD pattern.

[0157] In some embodiments, the crystalline tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, or a solvate thereof, is characterized by the TGA trace shown in FIG. 5 . Crystalline tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carba The main exothermic event in the DSC of mate, or its solvates, occurred at a temperature limit of 231.8°C and an energy of -52.9 kJ / kg (Figure 6).

[0158] The present disclosure provides a process for preparing crystalline tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, formula (6a), or a solvate thereof, comprising: (a) treating a compound of formula (6) or a salt or solvate thereof with isopropyl acetate (IPAc) to form a solution; (b) adding water to the solution of step (a) to form a mixture; (c) adding dichloromethane to the mixture from step (b) to form a mixture; (d) seeding the mixture from step (c); (e) isolating the resulting solid to obtain crystalline Formula (6a) or a solvate thereof.

[0159] In some embodiments, step (d) is performed at a reduced temperature, e.g., about 15-25°C, e.g., about 15-20°C or about 20-25°C.

[0160] Crystalline tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamide)-2-hydroxy In some embodiments of the process for preparing (cyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, dichloromethane / isopropyl acetate (50 / 50 v / v) containing 1% water, isopropyl acetate / dichloromethane (71 / 29 v / v) containing 2% water, or isopropyl acetate / dichloromethane (71 / 29 v / v) containing 8% water may be used. In certain such embodiments, dichloromethane / isopropyl acetate (50 / 50 v / v) containing 1% water may be used. Isopropyl acetate is not required for crystallization, but may be present as an extractant. The solid isolated as a sticky solid from dichloromethane / isopropyl acetate (50 / 50 v / v) containing 1% water could be easily filtered, and some deliquescence was observed from the solid isolated from both 2% and 8% water isopropyl acetate / dichloromethane (71 / 29 v / v). Furthermore, the material isolated from 1% water isopropyl acetate / dichloromethane (50 / 50 v / v) was crystalline. However, the material isolated from 2% water isopropyl acetate / dichloromethane (71 / 29 v / v) was irregular, and the material isolated from 8% water isopropyl acetate / dichloromethane (71 / 29 v / v) may contain a small amount of x-ray amorphous material. The crystallization conditions tested are summarized in Example 2.

[0161] Compounds 7 and 7a In some embodiments, an intermediate in the synthesis of a compound of formula (9), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, is a compound of formula (7): [ka] or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof. In certain such embodiments, the compound of formula (7) is of the following formula: [ka] (7a) or a salt or solvate thereof. In certain such embodiments, the compound of Formula (7a) is crystalline tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, or a solvate thereof.

[0162] In some embodiments, the crystalline tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, or a solvate thereof, is characterized by an XRPD pattern having peak positions substantially in accordance with those shown in FIG. 7 and Table 2. In some embodiments, for example as shown in Table 2, there is a variation of about ±0.2 degrees 2θ for the diffraction angles in the XRPD patterns. [Table 2]

[0163] In certain embodiments, crystalline tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydroxybutanamido Hydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, or a solvate thereof, is characterized by one or more 2θ values ​​at about 5.17, 7.39, 10.85, and 12.17 degrees in X-ray powder diffraction, where there is a variation of about ±0.2 degrees 2θ relative to the diffraction angles in the XRPD pattern.

[0164] In some embodiments, crystalline tert-butyl ((2R,3R,4R,5R)-2 -(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, or a solvate thereof, is characterized by the TGA trace shown in FIG. The DSC profile of crystalline tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, or a solvate thereof, is shown in FIG.

[0165] The present disclosure provides a process for preparing crystalline tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, formula (7a), or a solvate thereof, comprising: (a) treating a compound of formula (7a) or a salt or solvate thereof with isopropyl acetate (IPAc) to form a solution; (b) adding acetonitrile to the solution of step (a) to form a mixture; (c) seeding the mixture from step (b); (d) isolating the resulting solid to obtain crystalline Formula (7a) or a solvate thereof.

[0166] In some embodiments of the process for preparing crystalline tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, 10% v / v IPAc / ACN with 0.75-2% w / w water added with seeding may be used. Additionally, a long hold time at the seeding temperature (e.g., 60-65°C for over 2 hours) and a slow cooling ramp (e.g., 5-10°C / hour decrease from 60°C to 0°C) can be used to obtain a fluid slurry. Water content can be used to control the robustness of the crystallization. Crystallizations with 0.5-2% added water can be more reproducible and improve purity, with consistent recoveries (e.g., typically greater than 80%). This procedure can sufficiently remove unreacted compound of formula (6a), penta-Boc impurities (e.g., 63% combined removal), and dialkylated by-products (e.g., 36% removal), providing a solid product that is easily filterable and washable. The crystallization conditions tested are summarized in Example 3 and Tables 7-11.

[0167] Exemplary Embodiments Some embodiments of the present disclosure are the following embodiment I.

[0168] Embodiment I-1. A process for preparing a compound of formula (2), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, comprising: (a) A compound of formula (1): [ka] (1) or an enantiomer thereof or a diastereomer thereof is contacted with 1-{[(p-nitrobenzyl)oxy]carbonyl}-1H-benzotriazole (PNZ-Bt) to produce a compound of formula (2): [ka] (2) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. During the ceremony, [ka] is a single or double bond, R 1 is H or C1-C3 alkyl, R 2 is H or C1-C3 alkyl, R 3 is H or C1-C3 alkyl.

[0169] Embodiment I-2 The process of embodiment I-1, wherein step (a) is carried out in the presence of a solvent selected from the group consisting of dichloromethane, methanol, and combinations thereof.

[0170] Embodiment I-3 The process of embodiment I-1 or I-2, wherein PNZ-Bt is present in about 1.0 to 1.2 molar equivalents relative to the compound of formula (1) or its enantiomer or diastereomer.

[0171] Embodiment I-4. Step (b1) or (b2): (b1)R 1 , R 2 , and R 3 is H, the compound of formula (2), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, is contacted with a Boc protecting group reagent to give a compound of formula (3): [ka] (3) or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof; (b2)R 1 , R 2 , or R 3 is independently a C1-C3 alkyl, first remove the C1-C3 alkyl, and then contact the compound of formula (2), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, with a Boc protecting group reagent to obtain a compound of formula (3): [ka] (3) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof.

[0172] Embodiment I-5. The process of embodiment I-4, wherein the Boc protecting group reagent is Boc2O or Boc-ONb.

[0173] Embodiment I-6 The process of embodiment I-4 or I-5, wherein step (b1) or (b2) is carried out in the presence of a Lewis acid.

[0174] Embodiment I-7. The process of embodiment I-6, wherein the Lewis acid is Zn(OAc)2, ZnCl2, or Zn(OPiv)2.

[0175] Embodiment I-8 The process of embodiment I-6, wherein the Lewis acid comprises copper ions or nickel ions.

[0176] Embodiment I-9 The process of any one of embodiments I-4 to I-8, wherein step (b1) or (b2) is carried out in the presence of triethylamine.

[0177] Embodiment I-10 The process of any one of embodiments I-4 to I-8, wherein step (b1) or (b2) is carried out in the presence of methanol.

[0178] Embodiment I-11. (c) a compound of formula (3), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, [ka] to produce a compound of formula (4): [ka] (4) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof.

[0179] Embodiment I-12. The process of embodiment I-11, wherein step (c) is carried out in the presence of an activating reagent and a peptide coupling reagent.

[0180] Embodiment I-13 The process of embodiment I-12, wherein the activating reagent is HOBt.

[0181] Embodiment I-14. The activating reagent comprises: [ka] The process of embodiment I-13, wherein the compound is present in an amount of about 0.05 to 1.0 molar equivalents relative to the compound.

[0182] Embodiment I-15. The process of embodiment I-12, wherein the peptide conjugation reagent is EDAC or PyBOP.

[0183] Embodiment I-16. The peptide conjugation reagent comprises: [ka] The process of embodiment I-15, wherein the compound is present in an amount of about 1.0 to 1.4 molar equivalents relative to the compound.

[0184] Embodiment I-17. The process of any one of embodiments I-11 to I-16, wherein step (c) is carried out under acidic conditions.

[0185] Embodiment I-18. The process according to embodiment I-17, wherein the acidic conditions are about pH 4 to 7. Seth.

[0186] Embodiment I-19. The process of embodiment I-17, wherein the acidic conditions are about pH 5.

[0187] Embodiment I-20. The process of any one of embodiments I-11 to I-19, further comprising preparing a crystalline form of a compound of formula (4), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0188] Embodiment I-21. The process of any one of embodiments I-11 to I-20, further comprising isolating the compound of formula (4), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0189] Embodiment I-22. (d) contacting a compound of formula (4), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, with a Boc protecting group reagent to obtain a compound of formula (5): [ka] (5) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof.

[0190] Embodiment I-23 The process of embodiment I-22, wherein the Boc protecting group reagent is Boc2O.

[0191] Embodiment I-24 The process of embodiment I-22 or I-23, wherein step (d) is carried out in the presence of an alcohol.

[0192] Embodiment I-25 The process of embodiment I-24, wherein the alcohol is methanol.

[0193] Embodiment I-26 The process of any one of embodiments I-22 to I-25, wherein step (d) is conducted at a temperature of up to about 60°C.

[0194] Embodiment I-27. (e) contacting a compound of formula (5), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, with a PNZ deprotecting reagent to produce a compound of formula (6): [ka] (6) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof.

[0195] Embodiment I-28 The process of embodiment I-27, wherein the PNZ deprotecting reagent is sodium dithionite.

[0196] Embodiment I-29. The process of embodiment I-27 or I-28, further comprising preparing a crystalline form of a compound of formula (6), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0197] Embodiment I-30. The process of any one of embodiments I-27 to I-29, further comprising isolating the compound of formula (6), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0198] Embodiment I-31. (f) a compound of formula (6), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, [ka] (In the formula, LG 1 is a leaving group) to produce a compound of formula (7): [ka] (7) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof.

[0199] Embodiment I-32 The process of embodiment I-31, wherein the leaving group is iodo.

[0200] Embodiment I-33. [ka] The process of embodiment I-31, wherein is present in about 1.0 to 1.5 molar equivalents relative to the compound of Formula (6).

[0201] Embodiment I-34 The process of any one of embodiments I-31 to I-33, wherein step (f) is conducted under substantially water-free conditions.

[0202] Embodiment I-35. The process of any one of embodiments I-31 to I-34, wherein step (f) is carried out in the presence of a solvent selected from the group consisting of acetonitrile, acetone, and combinations thereof.

[0203] Embodiment I-36 The process of any one of embodiments I-31 to I-35, wherein step (f) is carried out in the presence of NaHCO3.

[0204] Embodiment I-37. The process of any one of embodiments I-31 to I-36, wherein step (f) is carried out at a temperature of about 30°C to 40°C.

[0205] Embodiment I-38. The process of any one of Embodiments I-31 through I-37, further comprising adding 1,4-diazabicyclo[2.2.2]octane (DABCO) to the reaction mixture.

[0206] Embodiment I-39. The process of any one of embodiments I-31 to I-38, further comprising preparing a crystalline form of a compound of formula (7), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0207] Embodiment I-40. The process of any one of embodiments I-31 to I-39, further comprising isolating the compound of formula (7), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0208] Embodiment I-41. (g) contacting the compound of formula (7) with a Boc removal reagent to produce a compound of formula (8): [ka] (8) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof.

[0209] Embodiment I-42 The process of embodiment I-41, wherein the Boc removal reagent is TFA, thereby obtaining a TFA salt of the compound of formula (8) or a solvate thereof or an enantiomer thereof or a diastereomer thereof.

[0210] Embodiment I-42a. Compound (IMP-1) [ka] (IMP-1) The process of embodiment I-41 or I-42, wherein is present in an amount of less than 7% immediately after the reaction (e.g., before any purification).

[0211] Embodiment I-42b. Compound (IMP-1) [ka] (IMP-1) The process of embodiment I-41 or I-42, wherein is present in an amount of less than 2.5% immediately after the reaction (e.g., before any purification).

[0212] Embodiment I-43 The process of embodiment I-42, further comprising removing the TFA salt to obtain a compound of formula (8), or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0213] Embodiment I-44. Process embodiment I-41 or I-43 further comprising (h) salt formation with an acid to obtain a salt of a compound of Formula (8) or a solvate thereof or an enantiomer thereof or a diastereomer thereof.

[0214] Embodiment I-45. The acid in step (h) is sulfuric acid, thereby producing the sulfate salt of the compound of formula (9): [ka] or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, wherein x is 1 to 5.

[0215] Embodiment I-46. R 1 , R 2 , or R 3 is H. 10. The process according to any one of claims 1 to 9.

[0216] Embodiment I-47. [ka] The process of any one of embodiments I-1 to I-46, wherein is a double bond.

[0217] Embodiment I-48. The stereochemistry at carbon atoms 1, 3, 4, 5, 6, 1', 2', 1", 2", 3", and 4" in formulas (1) to (3) is shown as in formula (X): [ka] The process of any one of embodiments I-1 to I-10, wherein represents a hydrogen or a point of attachment to a moiety: [ka] (X).

[0218] Embodiment I-49. The stereochemistry at carbon atoms 1, 3, 4, 5, 6, 1', 2', 1", 2", 3", 4", and 1-z in formulas (4)-(9) is shown as in formula (Y): [ka] The process of any one of embodiments I-11 to I-47, wherein represents a hydrogen or a point of attachment to a moiety: [ka] (Y).

[0219] Embodiment I-50. A compound of formula (5): [ka] (5) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, comprising the steps of: The process comprises: (a) A compound of formula (4): [ka] (4) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, with a Boc protecting group reagent, wherein [ka] is a single or double bond.

[0220] Embodiment I-51. The compound of formula (4), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, is a compound of formula (3): [ka] (3) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, [ka] The process of embodiment I-50, wherein the compound is prepared by contacting the compound with

[0221] Embodiment I-52. A compound of formula (3), or a salt thereof, or a solvate thereof, or The enantiomer or diastereomer thereof is (b1) A compound of formula (2a): [ka] (2a), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, with a Boc protecting group reagent; (b2) A compound of formula (2): [ka] (2) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, wherein C1-C3 alkyl is removed (In the formula, R 1 is H or C1-C3 alkyl, and R 2 is H or C1-C3 alkyl, and R 3 is H or C1-C3 alkyl, and R 1 , R 2 , or R 3 one or more of which is independently C1-C3 alkyl; The process according to embodiment I-51, wherein the compound of formula (2), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, is then prepared by contacting the compound of formula (2), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, with a Boc protecting group reagent.

[0222] Embodiment I-53. The compound of formula (2), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, is a compound of formula (1): [ka] (1) or an enantiomer thereof or a diastereomer thereof with 1-{[(p-nitrobenzyl)oxy]carbonyl}-1H-benzotriazole (PNZ-Bt).

[0223] Embodiment I-54. The process of any one of embodiments I-50 to I-53, wherein the Boc protecting group reagent is Boc2O.

[0224] Embodiment I-55. Step (a), (b1), or (b2) is carried out in the presence of an alcohol The process of any one of embodiments I-50 to I-54, wherein

[0225] Embodiment I-56 The process of embodiment I-55, wherein the alcohol is methanol.

[0226] Embodiment I-57. The process of any one of embodiments I-50 to I-56, wherein step (a), (b1), or (b2) is conducted at a temperature of up to about 60°C.

[0227] Embodiment I-58. (e) contacting a compound of formula (5), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, with a PNZ deprotecting reagent to produce a compound of formula (6): [ka] (6) The process of any one of embodiments I-50 to I-57, further comprising obtaining a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof.

[0228] Embodiment I-59. The process of embodiment I-58, wherein the PNZ deprotecting reagent is sodium dithionite.

[0229] Embodiment I-60. The process of any one of embodiments I-50 to I-59, further comprising preparing a crystalline form of a compound of Formula (6), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0230] Embodiment I-61. The process of any one of embodiments I-50 to I-60, further comprising isolating the compound of formula (6), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0231] Embodiment I-62. (f) a compound of formula (6), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, [ka] (In the formula, LG 1 is a leaving group) to produce a compound of formula (7): [ka] (7) The process of any one of embodiments I-50 to I-61, further comprising obtaining a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof.

[0232] Embodiment I-63 The process of embodiment I-62, wherein the leaving group is iodo.

[0233] Embodiment I-64. [ka] The process of embodiment I-62, wherein is present in about 1.0 to 1.5 molar equivalents relative to the compound of Formula (6).

[0234] Embodiment I-65. The process of any one of embodiments I-62 to I-64, wherein step (f) is conducted under substantially water-free conditions.

[0235] Embodiment I-66. The process of any one of embodiments I-62 to I-65, wherein step (f) is carried out in the presence of a solvent selected from the group consisting of acetonitrile, acetone, and combinations thereof.

[0236] Embodiment I-67. The process of any one of embodiments I-62 to I-66, wherein step (f) is carried out in the presence of NaHCO3.

[0237] Embodiment I-68. The process of any one of embodiments I-62 to I-67, wherein step (f) is carried out at a temperature of about 30°C to 40°C.

[0238] Embodiment I-69. The process of any one of embodiments I-62 through I-68, further comprising adding 1,4-diazabicyclo[2.2.2]octane (DABCO) to the reaction mixture.

[0239] Embodiment I-70. The process of any one of embodiments I-62 to I-69, further comprising preparing a crystalline form of a compound of formula (7), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0240] Embodiment I-71. The process of any one of embodiments I-62 to I-70, further comprising isolating the compound of formula (7), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0241] Embodiment I-72. (g) A compound of formula (7), a salt thereof, a solvate thereof, or an enantiomer thereof or a diastereomer thereof is contacted with a Boc removal reagent to give a compound of formula (8): [ka] (8) The process according to any one of embodiments I-62 to I-71, further comprising obtaining a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof.

[0242] Embodiment I-73 The process of embodiment I-72, wherein the Boc removal reagent is TFA, thereby obtaining a TFA salt of the compound of formula (8) or a solvate thereof or an enantiomer thereof or a diastereomer thereof.

[0243] Embodiment I-74 The process of embodiment I-73, further comprising removing the TFA salt to obtain a compound of formula (8), or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0244] Embodiment I-75. The process of embodiment I-72 or I-74, further comprising (h) salt formation with an acid to obtain a salt of the compound of formula (8) or a solvate thereof or an enantiomer thereof or a diastereomer thereof.

[0245] Embodiment I-76. The acid in step (h) is sulfuric acid, thereby producing the sulfate salt of the compound of formula (9): [ka] or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, wherein x is 1 to 5.

[0246] Embodiment I-77. A compound of formula (7): [ka] (7) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, the process comprising: (f) a compound of formula (6), [ka] (6) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, [ka] wherein LG 1 is the leaving group, [ka] is a single or double bond.

[0247] Embodiment I-78. The compound of formula (6), or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, is a compound of formula (5): [ka] (5) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, with a PNZ deprotecting reagent.

[0248] Embodiment I-79. The compound of formula (5), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, is a compound of formula (4): [ka] (4) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, with a Boc protecting group reagent.

[0249] Embodiment I-80. The compound of formula (4), or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, is a compound of formula (3): [ka] (3) a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, [ka] The process of embodiment I-79, wherein the compound is prepared by contacting the compound with

[0250] Embodiment I-81. A compound of formula (3), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, (b1) A compound of formula (2a): [ka] (2a), or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof with a Boc protecting group reagent; or (b2) A compound of formula (2): [ka] (2) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, wherein C1-C3 alkyl is removed (In the formula, R 1 is H or C1-C3 alkyl, and R 2 is H or C1-C3 alkyl, and R 3 is H or C1-C3 alkyl, and R 1 , R 2 , or R 3 one or more of which is independently C1-C3 alkyl; The process of embodiment I-80, wherein the compound of Formula (2) is then prepared by contacting the compound of Formula (2) with a Boc protecting group reagent.

[0251] Embodiment I-82. The compound of formula (2), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, is a compound of formula (1): [ka] (1) The process of embodiment I-81, wherein the compound is prepared by contacting 1-{[(p-nitrobenzyl)oxy]carbonyl}-1H-benzotriazole (PNZ-Bt), or an enantiomer thereof, or a diastereomer thereof, with 1-{[(p-nitrobenzyl)oxy]carbonyl}-1H-benzotriazole (PNZ-Bt).

[0252] Embodiment I-83 The process of any one of embodiments I-77 to I-82, wherein the leaving group is iodo.

[0253] Embodiment I-84. [ka] The process of embodiment I-83, wherein is present in about 1.0 to 1.5 molar equivalents relative to the compound of Formula (6).

[0254] Embodiment I-85. The process of any one of embodiments I-77 to I-84, wherein step (f) is conducted under substantially water-free conditions.

[0255] Embodiment I-86. The process of any one of embodiments I-77 to I-85, wherein step (f) is carried out in the presence of a solvent selected from the group consisting of acetonitrile, acetone, and combinations thereof.

[0256] Embodiment I-87. Embodiment I-7, wherein step (f) is carried out in the presence of NaHCO3 7 to I-86.

[0257] Embodiment I-88. The process of any one of embodiments I-77 to I-87, wherein step (f) is carried out at a temperature of about 30°C to 40°C.

[0258] Embodiment I-89. The process of any one of embodiments I-77 through I-88, further comprising adding 1,4-diazabicyclo[2.2.2]octane (DABCO) to the reaction mixture.

[0259] Embodiment I-90. The process of any one of embodiments I-77 to I-89, further comprising preparing a crystalline form of a compound of formula (7), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0260] Embodiment I-91. The process of any one of embodiments I-77 to I-90, further comprising isolating the compound of formula (7), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof.

[0261] Embodiment I-92. (g) contacting a compound of formula (7), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, with a Boc removal reagent to obtain a compound of formula (8): [ka] (8) The process of any one of embodiments I-77 to I-91, further comprising obtaining a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof.

[0262] Embodiment I-93 The process of embodiment I-92, wherein the Boc removal reagent is TFA, thereby obtaining a TFA salt of the compound of formula (8) or a solvate thereof or an enantiomer thereof or a diastereomer thereof.

[0263] Embodiment I-94 The process of embodiment I-93, further comprising removing the TFA salt to obtain a compound of formula (8) or a solvate thereof or an enantiomer thereof or a diastereomer thereof.

[0264] Embodiment I-95. The process of embodiment I-92 or I-94, further comprising (h) salt formation with an acid to obtain a salt of the compound of formula (8) or a solvate thereof or an enantiomer thereof or a diastereomer thereof.

[0265] Embodiment I-96 The acid in step (h) is sulfuric acid, thereby producing the sulfate salt of the compound of formula (9): [ka] or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, wherein x is 1 to 5.

[0266] Embodiment I-97. [ka] The process of any one of embodiments I-50 to I-96, wherein is a double bond.

[0267] Embodiment I-98. A compound of formula (4): [ka] (4) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof.

[0268] Embodiment I-99 The compound of formula (4) has the formula: [ka] (4a) or a salt or solvate thereof.

[0269] Embodiment I-100. Crystalline tert-butyl ((2S,3R)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-6-(((((4-nitrobenzyl)oxy)carbonyl)amino)methyl)-3,4-dihydro-2H-pyran-3-yl)carbamate, Formula (4a), or a solvate thereof.

[0270] Embodiment I-101. Crystalline tert-butyl((2S,3R)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-(( 1. A process for preparing S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-6-(((((4-nitrobenzyl)oxy)carbonyl)amino)methyl)-3,4-dihydro-2H-pyran-3-yl)carbamate, formula (4a), or a solvate thereof, comprising: (a) treating a compound of formula (4a) or a salt or solvate thereof with acetonitrile to form a solution; (b) heating the solution from step (a); (c) adding water to the heated solution of step (b); (d) cooling the solution from step (c); (e) charging the solution from step (d) with seed crystals; (f) isolating the resulting solid to obtain crystalline Formula (4a) or a solvate thereof.

[0271] Embodiment I-102. Crystalline tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a), or a solvate thereof.

[0272] Embodiment I-103. A process for preparing crystalline tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a), or a solvate thereof, comprising: (a) treating a compound of formula (6a) or a salt or solvate thereof with isopropyl acetate (IPAc) to form a solution; (b) adding water to the solution of step (a) to form a mixture; (c) adding dichloromethane to the mixture from step (b) to form a mixture; (d) seeding the mixture from step (c); (e) isolating the resulting solid to obtain crystalline Formula (6a) or a solvate thereof.

[0273] Embodiment I-104. The process of embodiment I-103, wherein step (d) is carried out at a low temperature.

[0274] Embodiment I-105. A compound of formula (7): [ka] A salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof.

[0275] Embodiment I-106. The compound of formula (7) has the following formula: [ka] (7a) The compound of embodiment I-105, which is: or a salt or solvate thereof.

[0276] Embodiment I-107. Crystalline tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-dihydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (7a), or a solvate thereof.

[0277] Embodiment I-108. A process for preparing crystalline tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-dihydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (7a), or a solvate thereof, comprising: (a) treating a compound of formula (7a) or a salt or solvate thereof with isopropyl acetate (IPAc) to form a solution; (b) adding acetonitrile to the solution of step (a) to form a mixture; (c) seeding the mixture from step (b); (d) isolating the resulting solid to obtain crystalline Formula (7a) or a solvate thereof. [Example]

[0278] The present disclosure is further illustrated by the following examples, which should not be construed as limiting the disclosure in scope or spirit to the specific procedures described herein. It should be understood that the examples are provided to illustrate particular embodiments and are not intended to limit the scope of the disclosure. It is further to be understood that one may have resort to various other embodiments, modifications, and equivalents thereof that may suggest themselves to those skilled in the art without departing from the scope of the appended claims.

[0279] Unless otherwise specified, starting components may be obtained from sources such as Sigma Aldrich, Lancaster Synthesis, Inc., Maybridge, Matrix Scientific, TCI, and Fluorochem (USA), or synthesized according to sources known to those skilled in the art (e.g., Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, 5th Edition (Wiley, December 2000)), or prepared as described herein.

[0280] Sisomicin free base is a fermented glycoside and was obtained from Zhejiang Zhenyuan Pharmaceutical Co. Ltd. Boc-(S)-HABA was obtained from Senn Chemicals AG or Porton Fine Chemicals Inc. PNZ-Bt was obtained from Luxembourg BioTechnologies LTD (KINSY SL) or Porton Fine Chemicals Inc. 2-Iodoethanol was obtained from Dona Chemicals (Poland).

[0281] The following abbreviations have the following meanings unless otherwise indicated, and any other abbreviations used and not defined herein have their standard, generally accepted meaning. %a / a: Area normalized percent Ac: Acetate ACN: acetonitrile Boc: tert-butoxycarbonyl BocO2: Di-tert-butyl dicarbonate or Boc anhydride Boc-ONb: tert-butyl ((4R,7S)-1,3-dioxo-1,3,3a,4,7,7a-hexahydro-2H-4,7-methanoisoindol-2-yl) carbonate DABCO: 1,4-diazabicyclo[2.2.2]octane DBU: 1,8-diazabicyclo[5.4.0]undec-7-ene DCM: dichloromethane DI: deionized water DIPE: Diisopropyl ether DIPEA: N,N-diisopropylethylamine DMF: dimethylformamide, DSC: Differential scanning calorimetry EDAC: N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride EtOH: ethanol GC: Gas chromatography h or hr: hours HABA: 4-amino-2-hydroxy-butanoic acid HCl: Hydrochloric acid HOBt: 1-hydroxybenzotriazole hydrate HPLC: High-Performance Liquid Chromatography IPA: Isopropyl alcohol IPAc: Isopropyl acetate LC / MS: Liquid chromatography / mass spectrometry MeCN: acetonitrile MeOH: Methanol min:minutes MTBE: Methyl tert-butyl ether NaOH: Sodium hydroxide PNZ-Bt: 1-{[(p-nitrobenzyl)oxy]carbonyl}-1H-benzotriazole ppm: parts per million PrOH: Propanol PyBOP: (benzotriazol-1-yloxy)tripyrrolidinophosphonium hexafluorophosphate RT or rt: room temperature TBDMS: tert-butyldimethylsilyl TEA: Triethylamine TFA: Trifluoroacetic acid TGA::Thermogravimetric analysis THF: tetrahydrofuran UPLC: Ultra Performance Liquid Chromatography UV: Ultraviolet light v / v: volume fraction vol or vols: volume %w / w: weight by weight percent wt: weight XRPD: X-ray powder diffraction Zn(OPiv)2: Zinc pivalate

[0282] X-ray powder diffraction XRPD patterns were collected on a Panalytical X'Pert PRO MPD diffractometer using an incident beam of Cu radiation generated using an Optix long microfocus source. An elliptically graded multilayer mirror was used to focus the Cu Kα x-rays through the specimen and onto the detector. Prior to analysis, a silicon specimen (NIST SRM 640d) was analyzed to confirm that the observed position of the Si111 peak matched the NIST-certified position. The specimen was sandwiched between 3 μm-thick films and analyzed in transmission geometry. A beam stop, a short antiscatter extension, and an antiscatter knife edge were used to minimize background caused by air. Soller slits for the incident and diffracted beams were used to minimize broadening due to axial divergence. Diffraction patterns were collected using a scanning position-sensitive detector (X'Celerator) positioned 240 mm from the specimen and Data Collector software v.2.2b.

[0283] thermal analysis Differential scanning calorimetry (DSC) was performed using a TA Instruments DSC with a temperature gradient of 0° C. to 300° C. at a rate of 10° C. / min. Standard aluminum pans were used.

[0284] Thermogravimetric analysis (TGA) was performed using a TA Instruments 2950 thermogravimetric analyzer. Temperature calibration was performed using nickel and AlumeI™. Each sample was placed in a platinum pan and placed in a TG furnace. The furnace was heated under a nitrogen purge.

[0285] Example 1 - Synthesis Protocol for Compound 4a A general synthetic protocol for compound 4a is detailed below. [ka] Part 1: Synthesis of compound 2b [ka]

[0286] Sisomicin free base (1.0 kg ± 1%, 2.23 mol) is charged to the reactor, followed by MeOH (3.96 kg ± 5% or 5 L ± 5%) and then DCM (6.64 kg ± 5% or 5 L ± 5%). The temperature is then stabilized at 15 ± 5 °C, and the mixture is stirred to achieve complete dissolution. To aid dissolution, the temperature can be increased to approximately 30 °C. After dissolution, the mixture is cooled to a temperature of 15 ± 5 °C. In a separate mixing tank, PNZ-Bt [(0.696 kg) ± 1%, 2.33 mol)] is dissolved in DCM (18.59 kg ± 5% or 14 L ± 5%). While maintaining a batch temperature of 15 ± 5 °C, the PNZ-Bt solution is charged to the reactor over a period of approximately 1 to approximately 4 hours. When preparing the PNZ-Bt solution, do not heat the charging tank jacket above approximately 35 °C to facilitate dissolution of the PNZ-Bt. Complete dissolution of the PNZ-Bt is not necessary.

[0287] Rinse the filling system used to fill the PNZ-Bt solution with DCM (1.33 kg ± 5% or 1 L ± 5%) and pump the rinse into the reactor (T バッチ =15±5°C). The batch is stirred at 15±5°C and the contents are sampled for reaction completion. The reaction is considered complete when the sisomicin content is about 2.0% or less by area as assessed by HPLC analysis (see Table 3 for the HPLC method used). The first sample is taken about 15 minutes to 12 hours after the PNZ-Bt charge is complete. In some embodiments, the first sample is taken about 30 minutes after the PNZ-Bt charge is complete. Additional PNZ-Bt in DCM solution is charged as needed to complete the reaction. The additional PNZ-Bt charge is calculated by the following formula: Charge = P1 * D1 / (100 - D1 ± 1%), where P1 = amount of PNZ-Bt initially charged in kg, and D1 = amount of unconsumed sisomicin in % area by HPLC. Once the reaction is complete, the batch is concentrated under vacuum at a jacket temperature of about 40°C or less (e.g., 10-40°C) until the residual volume is 5 L ± 5%.

[0288] The reactor containing compound 2b is then charged with MeOH (5.54 kg ± 5% or 7.00 L ± 5%). The mixture can be maintained at a temperature of about 25°C or less (e.g., 0-25°C) for about 48 hours or less (e.g., 0-48 hours) before the next reaction (Part 2). [Table 3] Part 2: Synthesis of compound 3a [ka]

[0289] While maintaining a batch temperature of about 27 °C to about 35 °C (target about 33 °C), charge triethylamine [(1.48 L) ± 2% or (1.08 kg ± 2%)] to the reactor containing compound 2b mentioned at the end of Part 1. Rinse the loading system used to load triethylamine with MeOH (2.38 kg ± 5% or 3.00 L ± 5%) and add the rinse to the reaction mixture. Allow the batch temperature to stabilize at about 27 °C to about 35 °C (target about 33 °C). Charge Zn(OAc) 2H O (1.63 kg ± 2%) to the batch, and rinse the loading system used to load zinc acetate dihydrate with MeOH (2.38 kg ± 5%, or 3.00 L ± 5%) and add the rinse to the reaction mixture. Stir the mixture at about 27 °C to about 35 °C (target about 33 °C) for about 30 minutes to 12 hours. In certain embodiments, the mixture is stirred at about 27° C. to about 35° C. (target about 33° C.) for about 60 minutes or less.

[0290] In a separate mixing tank, prepare a solution of BocO [(2.55 kg) ± 2%, 11.7 mol] in MeOH (1.58 kg ± 5% or 2.00 L ± 5%). Charge the prepared BocO solution to the reactor over a period of about 15 minutes to 12 hours while maintaining a batch temperature of about 27°C to about 35°C (target about 33°C). In certain embodiments, charge the prepared BocO solution to the reactor over a period of about 1 hour or more while maintaining a batch temperature of about 27°C to about 35°C (target about 33°C). The reactor is charged from below. The charging system used for the Boc2O solution is rinsed with methanol (0.16 kg ± 5% or 0.20 L ± 5%) and the rinse is added to the reactor.

[0291] The batch is held at a target temperature of about 20-40° C. for about 3-24 hours and the sample contents are sampled for reaction completion. In certain embodiments, the batch is held at a target temperature of about 33° C. for up to about 5 hours and the sample contents are sampled for reaction completion. Mono-Boc-Compound 2b Intermediate to Compound 3a: [ka] The reaction is considered complete when the content of is about 2.0% or less by area by HPLC analysis (see Table 4 for the HPLC method used). The first sample taken to confirm reaction completion is taken after about 15 minutes to 12 hours. In certain embodiments, the first sample taken to confirm reaction completion is taken after about 5 hours or more, with subsequent samples (as needed) taken at about 3-hour intervals. The batch temperature during this hold does not exceed a range of about 27-35°C. In certain cases, additional BocO is charged to complete the reaction. The charge is made with the same concentration of BocO as used in the BocO solution prepared above. The amount of BocO charged is calculated according to the following formula: Charge = P2 * 2 * D2 / [100 - (2 * D20] ± 2%, where P2 = amount of BocO initially charged in kg, and D2 = amount of remaining mono-Boc-compound 2b in % area by HPLC.

[0292] Upon completion of the reaction, the reaction mixture is concentrated under vacuum at a jacket temperature of about 40°C or less (e.g., 20-40°C) until the residual volume is 12 L ± 5%. Maintain a batch temperature of about 20°C to about 30°C and hold within this temperature range for about 15 minutes to 12 hours while charging about 25% w / w (5.46 kg ± 5% or 6.00 L ± 5%) ammonia. In certain embodiments, maintain a batch temperature of about 20°C to about 30°C and hold within this temperature range for about 1 hour or less while charging about 25% w / w (5.46 kg ± 5% or 6.00 L ± 5%) ammonia. The addition is exothermic.

[0293] DCM (13.28 kg ± 5% or 10.00 L ± 5%) is charged to the batch and the contents are stirred at 25 ± 5°C for about 12 minutes to 12 hours. In certain embodiments, DCM (13.28 kg ± 5% or 10.00 L ± 5%) is charged to the batch and the contents are stirred at 25 ± 5°C for about 30 minutes or less. The contents are allowed to settle and separate for about 30 minutes to 12 hours. In certain embodiments, the contents are allowed to settle and separate for at least about 45 minutes or more. The organic phase (bottom phase) is transferred to a receiver and the aqueous phase is discharged for disposal. The product is in the organic phase.

[0294] The organic phase is charged back to the reactor. Approximately 25% w / w (2.28 kg ± 5% or 2.50 L ± 5%) ammonia and DI water (2.5 kg ± 5% or 2.5 L ± 5%) mixed in a mixing tank are charged to the organic phase and stirred at 25 ± 5°C for approximately 15 minutes to 12 hours. In certain embodiments, approximately 25% w / w (2.28 kg ± 5% or 2.50 L ± 5%) ammonia and DI water (2.5 kg ± 5% or 2.5 L ± 5%) mixed in a mixing tank are charged to the organic phase and stirred at 25 ± 5°C for approximately 30 minutes or less. The contents are allowed to settle and separate for approximately 30 minutes to 12 hours. In certain embodiments, the contents are allowed to settle and separate for at least approximately 45 minutes. The organic phase (bottom phase) is transferred to a receiver and the aqueous phase is discharged for disposal. The product is in the organic phase.

[0295] The organic phase is charged to a reactor, and MeOH (0.79 kg ± 5% or 1.00 L ± 5%) is charged to the organic phase and stirred at 25 ± 5°C for about 15 to about 30 minutes. DI water (5.0 kg ± 5%, or 5.0 L ± 5%) is charged to the mixture and stirred at 25 ± 5°C for about 15 minutes to 12 hours. In certain embodiments, DI water (5.0 kg ± 5%, or 5.0 L ± 5%) is charged to the mixture and stirred at 25 ± 5°C for about 30 minutes or less. The contents are allowed to settle and separate for about 30 minutes to 12 hours. In certain embodiments, the contents are allowed to settle and separate for at least about 1 hour or more. The organic phase (bottom phase) is transferred to a receiver, and the aqueous phase is discharged for disposal. The product is in the organic phase.

[0296] The organic phase is charged back to the reactor. MeOH (1.98 kg ± 5% or 2.50 L ± 5%) is charged to the organic phase and stirred at 25 ± 5°C for about 15 to about 30 minutes. DI water (5.0 kg ± 5% or 5.0 L ± 5%) is charged to the mixture and stirred at 25 ± 5°C for about 15 minutes to 12 hours. In certain embodiments, DI water (5.0 kg ± 5%, or 5.0 L ± 5%) is charged to the mixture and stirred at 25 ± 5°C for about 30 minutes or less. The contents are allowed to settle and separate for about 30 minutes to 12 hours. In certain embodiments, the contents are allowed to settle and separate for at least about 2 hours or more. The organic phase (lower phase) is transferred to a receiver and the aqueous phase is discharged for disposal. The product is in the organic phase. The batch is placed under vacuum at a jacket temperature of about 40°C or less (e.g., 20-40°C) until the residual volume is about 9 L ± 5%. The mixture can be maintained at a temperature of about 25° C. or less (eg, 0 to 25° C.) for about 48 hours or less (eg, 0 to 48 hours). [Table 4] Part 3: Synthesis of compound 4a [ka]

[0297] While maintaining a reaction temperature of 20±5°C, DI water (0.5 kg±5% or 0.5 L±5%) is charged to the Part 2 mixture containing Compound 3a. Boc-(S)-HABA [(0.512 kg)±2%, 2.34 mol] is charged to the reaction mixture, maintaining the temperature within 20±5°C. The charging system used to charge Boc-(S)-HABA is rinsed with DCM (0.27 kg±5% or 0.20 L±5%), and the rinse is added to the reaction mixture. The mixture is stirred at a batch temperature of 20±5°C.

[0298] Charge 1-hydroxybenzotriazole monohydrate (HOBt HO, 0.057 kg ± 2%, 0.42 mol) while maintaining a reaction temperature of 20 ± 5 °C. Rinse the charging system used to charge HOBt HO with DCM (0.27 kg ± 5% or 0.2 L ± 5%) and add the rinse to the reaction mixture.

[0299] While maintaining a temperature range of 20±5°C, the batch pH is adjusted to 5.0±0.2 by adding 2M HCl solution (as needed). The required acidic solution is prepared in a separate suitable container by adding concentrated HCl (1.392 kg±5% or 1.18 L±5%) to DI water (6.00 kg±5% or 6.00 L±5%). pH adjustment typically requires a charge of about 3.5 to about 4.5 L / kg. In certain cases, if the pH drops below about 4.8 (e.g., about 5.0±0.2), a solution of 2M NaOH is added (as needed) to bring the batch pH within the predetermined range of 5.0±0.2. In a specific example, a basic solution is prepared in a suitable container from NaOH (0.56 kg±5%) and DI water (7.0 kg±5% or 7.0 L±5%), as needed.

[0300] EDAC [(0.447 kg) ± 2%, 2.33 mol] is charged to the batch while maintaining a temperature range of 20 ± 5°C. The charging system used to charge EDAC is rinsed with DCM (0.27 kg ± 5% or 0.20 L ± 5%), and the rinse is added to the reaction mixture. The mixture is stirred at a reaction temperature of 20 ± 5°C for about 15 minutes to 6 hours and sampled for reaction completion. In certain embodiments, the mixture is stirred at a reaction temperature of 20 ± 5°C for about 1 hour or less and sampled for reaction completion. The reaction can be considered complete when the content of compound 3a relative to compound 4a is about 1.0% or less by area by HPLC analysis (method summarized in Table 4). The pH is checked at each sample and adjusted as necessary to maintain a pH of about 4.8 to about 6.0. In certain cases, HCl or NaOH solution is added as needed, as described above. The first sample is taken after a holding period of about 15 minutes to 6 hours. In certain embodiments, the first sample is collected after a holding period of about 1 hour. In certain embodiments, additional samples are withdrawn at intervals of about 3 hours. If the reaction is not complete after two samples are withdrawn, additional EDAC and Boc-(S)-HABA are charged to drive the reaction to completion according to the following formula: Charge = P3 * D3 / (100-D3), where P3 = the amount of EDAC or Boc-(S)-HABA initially charged in kg, and D3 = the amount of unconsumed Compound 3a in a / a %.

[0301] Once complete, add MeOH (1.58 kg ± 5%) while maintaining a reaction temperature of 20 ± 5 °C. Then, DCM (15.94 kg ± 5% or 12.00 L ± 5%) is charged to the reaction while maintaining a batch temperature of 20 ± 5°C. Then, DI water (5.0 kg ± 5% or 5.0 L ± 5%) is charged to the reaction while maintaining a batch temperature of 20 ± 5°C. The batch pH is adjusted to about 9.0 to about 10.0 by adding 2M NaOH solution (as needed) while maintaining a temperature of 25 ± 5°C. pH adjustment typically requires a 2M NaOH charge of about 3.5 to about 4.5 L / kg. If the batch pH is above 10.0, 2M HCl solution is charged to achieve the desired range. The mixture is stirred at a temperature of about 20°C to about 38°C for about 15 minutes to 12 hours. In certain embodiments, the mixture is stirred at a temperature of about 20°C to about 38°C for about 30 minutes or less. The contents are then allowed to settle for about 30 minutes to 12 hours and separated. In certain embodiments, the contents are then allowed to settle for at least about 1 hour or more and separated. The organic phase (bottom phase) is transferred to a receiver, and the aqueous phase is discharged for disposal. The product is in the organic phase. The organic phase is again charged to the reactor with MeOH (2.38 kg ± 5% or 3.00 L ± 5%) while maintaining the batch temperature between about 20°C and about 38°C. DI water (7.0 kg ± 5%, or 7.0 L ± 5%) is then charged to the mixture and stirred at a temperature of about 20°C to about 38°C for about 15 minutes to 12 hours. In certain embodiments, DI water (7.0 kg ± 5% or 7.0 L ± 5%) is then charged to the mixture and stirred at a temperature of about 20°C to about 38°C for about 30 minutes or less. The contents are allowed to settle for about 30 minutes to 12 hours and separated. In certain embodiments, the contents are allowed to settle and separate for at least about 1 hour. The organic (bottom) phase is transferred to a receiver and the aqueous phase is discharged to waste. The product is in the organic phase. The batch is concentrated under vacuum at a jacket temperature of about 40° C. or less (e.g., 20-40° C.) until the residual volume is about 10 L±5%.

[0302] Part 4: Crystallization of compound 4a Acetonitrile (7.87 kg ± 5% or 10.00 L ± 5%) is charged to the Part 3 batch over about 5 minutes to 4 hours. In certain embodiments, acetonitrile (7.87 kg ± 5% or 10.00 L ± 5%) is charged to the Part 3 batch over about 10 minutes. The mixture is concentrated under vacuum at a jacket temperature of about 40°C or less (e.g., 20-40°C) to obtain a final residual volume of about 10 L ± 5%. Acetonitrile (7.87 kg ± 5% or 10.00 L ± 5%) is charged to the batch and concentrated under vacuum at a jacket temperature of about 40°C or less (e.g., 20-40°C) to obtain a final residual volume of about 10 L ± 5%. Acetonitrile (varying amounts) is then charged to achieve a final batch volume of about 25 L ± 5%. The contents of the reactor are a thick, opaque slurry of white solids.

[0303] The batch is then heated to reflux (about 82°C) and held for about 5 minutes to 12 hours. In certain embodiments, the batch is then heated to reflux (about 82°C) and held for about 15 minutes or less. It is expected that not all solids will dissolve during the holding period. While maintaining reflux, DI water (0.375 kg ± 5%, or 0.375 L ± 5%) is charged to the mixture. The batch is stirred for about 30 to about 60 minutes to achieve a homogeneous solution. If a homogeneous solution is not achieved within about 30 to 60 minutes, an additional portion of DI water (0.125 kg ± 5% or 0.125 L ± 5%) is charged to dissolve any remaining solids. Adding more water typically has a slight beneficial effect on quality but may result in a lower yield. Once a homogeneous solution is achieved, the batch is cooled to a temperature of 75 ± 3°C over about 15 minutes to 12 hours. In certain embodiments, once a homogeneous solution is obtained, the batch is cooled to a temperature of 75±3° C. over a period of about 1 hour or less.

[0304] While maintaining a temperature of 75±3°C, the batch is charged with Compound 4a seed (0.01 kg±2%). The seed slurry charge vessel and lines are rinsed with acetonitrile (0.08 kg±5% or 0.10 L±5%) and the rinse is added to the batch. The batch is then agitated for about 15 minutes to 12 hours. In certain embodiments, the batch is then agitated for about 30 minutes or more. The batch is cooled to a temperature of 50±5°C over 30 minutes to 12 hours and further stirred with moderate agitation. The mixture is cooled to a temperature range of about -5 to about 5°C over about 1 hour and held for about 4 to 12 hours to form a thick slurry. In certain embodiments, the batch is cooled to a temperature of 50±5°C over about 2 hours or more and held with moderate agitation for an additional about 2 to 12 hours to form a thick slurry. The batch is cooled to a temperature range of about -5 to about 5°C over about 1 to 24 hours and held for an additional about 4 to 12 hours. In certain embodiments, the batch is cooled to a temperature range of about -5 to about 5°C over about 1 hour or more and held for an additional about 4 to 12 hours. The batch is filtered, deliquored, and the filter cake is washed with acetonitrile (0.79 kg±5% or 1.00 L±5%) at 0±5°C and deliquored.

[0305] The product is dried under vacuum at a temperature of about 55°C or less (e.g., 0-55°C). Drying is considered complete when the loss on drying is about 1% w / w or less. The product is dried under a stream of dry nitrogen. The dried product can be de-lumped by suitable sieving. The yield from sisomicin free base to compound 4a over the three steps is about 65%.

[0306] Seeded crystallization in acetonitrile with 1.5% DI water at 75±3°C followed by cooling may be selected due to its high yield of approximately 70%, high purity of at least approximately 88.08% (the purity of the material before crystallization was approximately 77.75%), and ease of filtering the mixture. However, after testing several crystallization procedures, acetonitrile with 1.5% DI water at 75±3°C followed by cooling was selected. These are detailed in Table 5. The use of water (approximately 1.5%) as a co-solvent with acetonitrile may reduce the processing volume required for crystallization. [Table 5-1] [Table 5-2] [Table 5-3] [Table 5-4] [Table 5-5]

[0307] Part 5: Characterization data for compound 4a The XRPD spectrum of compound 4a is shown in Figure 1. The TGA of compound 4a was consistent with an anhydrous / nonsolvated material, with only a 0.1 wt% change from 25 to 189 °C, suggesting low volatile content (Figure 2). The DSC profile of compound 4a is shown in Figure 3.

[0308] Example 2 - Synthesis Protocol for Compound 6a A general synthetic protocol for compound 6a is detailed below. [ka] Part 1: Synthesis of compound 5a [ka]

[0309] Compound 4a (1.0 kg ± 1%) and MeOH (7.92 kg ± 5% or 10.00 L ± 5%) are charged to the reactor. The mixture is heated to a temperature of 50 ± 5 °C. A solution of BocO (0.255 kg ± 2%) in methanol (0.20 kg ± 5% or 0.25 L ± 5%) is added to the reactor while maintaining a temperature of 50 ± 5 °C. The charging system used to charge the BocO solution is rinsed with methanol (0.20 kg ± 5% or 0.25 L ± 5%), and the rinse is added to the reaction mixture while maintaining a temperature of 50 ± 5 °C. The batch is held at 50 ± 5 °C until the reaction is complete. The reaction can be considered complete when the content of compound 4a is approximately 3.0% or less by area by HPLC (see Table 6 for the HPLC method used). The first sample for analysis is collected after approximately 15 minutes to 12 hours of reaction time. In certain embodiments, the first sample for analysis is collected after 3 hours of reaction time, and subsequent samples are collected at approximately 3-hour intervals as needed. If necessary to complete the reaction, additional Boc2O in methanol solution is added to the reaction mixture. The amount added is calculated according to the following formula: Loading = P1 × (A2 / [100-A2]) ± 1%, where P1 = the amount of Boc2O (kg) initially charged in the reaction, and A2 = the amount of unconsumed compound 4a in the final sample at a / a%.

[0310] Once the reaction is complete, the batch is stabilized at 20±5° C. The batch can be held at this temperature range for up to about 55 hours (e.g., 0-55 hours). [Table 6] Part 2: Synthesis of compound 6a [ka]

[0311] Deionized water (7.78 kg ± 5% or 7.78 L ± 5%) is charged to a reactor, and solid sodium hydroxide (0.39 kg ± 1%) is added, followed by stirring until visually dissolved. A portion of the deionized water may be charged after the sodium hydroxide charge and / or the sodium dithionite charge to rinse the charging device used to charge these materials. The temperature is stabilized at approximately 0-5°C. Sodium dithionite (1.196 kg ± 1%) is added to the basic aqueous solution while maintaining the solution temperature at approximately 0-5°C. Increasing the temperature during the addition may result in a lower purity product. The mixture is stirred at approximately 0-5°C for 5 minutes to 12 hours. In certain embodiments, the mixture is stirred at approximately 0-5°C for no more than about 15 minutes. The dithionite solution should be used within approximately 0-4 hours of charging NaSO. In certain embodiments, the dithionite solution should be used within approximately 90 minutes of charging NaSO.

[0312] Add the Part 1 reaction mixture to the basic sodium dithionite solution over a period of about 1 to 8 hours (e.g., 1 to 4 hours) while maintaining the temperature of the mixture at about -5°C to less than about 15°C. In certain embodiments, the Part 1 reaction mixture is added to the basic sodium dithionite solution over a period of about 1-4 hours, while maintaining the temperature of the mixture below about 10°C. The addition is exothermic, and faster addition results in a gummy solid. The loading system used to load the reaction mixture is rinsed with methanol (0.40 kg ± 5% or 0.50 L ± 5%), and the rinse is added to the batch. The batch is heated to a temperature of about 25°C to about 30°C over a period of about 1-4 hours. In certain embodiments, the batch is heated to a temperature of about 25°C to about 30°C over a period of about 2 hours. Typically, the maximum jacket temperature is about 25-35°C, maintaining a ΔT between the jacket temperature and the batch temperature of about 10°C or less (e.g., 0-10°C). In certain embodiments, the maximum jacket temperature is about 30°C, maintaining a ΔT between the jacket temperature and the batch temperature of about 10°C or less. The batch is stirred at a temperature of about 25-30°C until the reaction is complete. Higher reaction temperatures may result in higher amounts of impurities.

[0313] Contents of peaks with relative retention times less than or equal to 0.43: [ka] The reaction is considered complete when the % a / a is about 3.0% a / a or less by HPLC (similar to the method detailed in Table 6). In certain embodiments, the first sample is taken at the end of the heating period, with subsequent samples taken at about 3 hour intervals.

[0314] Upon completion of the reaction, the mixture is distilled under vacuum at a jacket temperature of about 20-40°C to a final volume of 13 L ± 5%. In certain embodiments, upon completion of the reaction, the mixture is distilled under vacuum at a jacket temperature of about 35°C or less to a final volume of 13 L ± 5%. IPAc (3.49 kg ± 5% or 4.00 L ± 5%) is charged to the batch while maintaining a temperature of about 25-40°C. Deionized water (7.0 kg ± 5% or 7.0 L ± 5%) is then charged to the batch while maintaining a temperature of about 25-40°C. The mixture is stirred at a temperature of about 30-40°C for about 15 minutes to 12 hours. In certain embodiments, the mixture is stirred at a temperature of about 30-40°C for about 20 minutes or longer. Complete dissolution of the salt is not necessary, as phase separation can proceed without interference from the presence of some undissolved salt.

[0315] Stop stirring and allow the layers to separate for about 30 minutes to 12 hours. In certain embodiments, stop stirring and allow the layers to separate for about 1 hour or longer. Transfer the aqueous phase (aqueous phase 1) to a receiver. Transfer the product-rich organic phase (organic phase 1) to another receiver. Charge IPAc (1.74 kg ± 5% or 2.00 L ± 5%) to aqueous phase 1 while maintaining a temperature of about 25-40°C. Stir the mixture at a temperature of 35 ± 5°C for about 15 minutes to 12 hours. In certain embodiments, stir the mixture at a temperature of 35 ± 5°C for about 20 minutes or longer. Salts may precipitate below about 30°C. Stop stirring and allow the layers to separate for about 30 minutes to 12 hours. In certain embodiments, stop stirring and allow the layers to separate for about 1 hour or longer. Discard the lower aqueous phase (aqueous phase 2).

[0316] Organic phases 1 and 2 are combined in a suitable receiving vessel. An approximately 6.5% w / w aqueous solution of sodium bicarbonate is prepared by dissolving NaHCO3 (0.42 kg ± 5%) in deionized water (6.00 kg ± 5% or 6.00 L ± 5%). The temperature of this solution is stabilized at 25 ± 5°C. Approximately 2 to 6 L of 6.5% w / w NaHCO3 solution is charged to the combined organic phases. In certain embodiments, approximately 3 L of 6.5% w / w NaHCO3 solution is charged to the combined organic phases. The solution is stirred at a temperature of 25 ± 5°C for approximately 15 minutes to 12 hours. In certain embodiments, In some embodiments, the solution is stirred at a temperature of 25±5°C for about 20 minutes or more. The stirring is then stopped, and the layers are allowed to separate for about 0 to 48 hours. In certain embodiments, the stirring is then stopped, and the layers are allowed to separate for about 1 hour or more. The lower aqueous phase is discarded. The organic phase (organic phase 3) may be maintained at about 25°C or below (e.g., 0 to 25°C) for about 0 to 48 hours. In certain embodiments, the lower aqueous phase is discarded. The organic phase (organic phase 3) may be maintained at about 25°C or below for up to about 24 hours.

[0317] Approximately 2-6 L of 6.5% w / w NaHCO3 solution is charged to organic phase 3. In certain embodiments, approximately 3 L of 6.5% w / w NaHCO3 solution is charged to organic phase 3. The mixture is stirred at a temperature of 25±5°C for approximately 30 minutes to 12 hours. In certain embodiments, the mixture is stirred at a temperature of 25±5°C for approximately 20 minutes or more. The stirring is then stopped and the layers are allowed to separate for approximately 1 hour or more. The lower aqueous phase is discarded. The organic phase (organic phase 4) may be maintained at or below approximately 20-25°C for up to approximately 24 hours. In certain embodiments, the organic phase (organic phase 4) may be maintained at or below approximately 25°C for up to approximately 24 hours.

[0318] Distill organic phase 4 under vacuum at a jacket temperature of about 50°C or less (e.g., 20-50°C) to a final volume of 3 L ± 5%. Charge IPAc (2.62 kg ± 5% or 3.00 L ± 5%) into the batch. Distill the mixture under vacuum at a jacket temperature of about 50°C or less (e.g., 20-50°C) to a final volume of 3 L ± 5%. Charge IPAc (2.62 kg ± 5% or 3.00 L ± 5%) into the batch. The mixture is then distilled under vacuum at a jacket temperature of about 50°C or less (e.g., 20-50°C) to a final volume of 4.5 L ± 5%. Then, charge deionized water (0.135 kg ± 5% or 0.135 L ± 5%) into the batch while maintaining a temperature of about 35-40°C. Adjust the batch temperature to about 15 to about 30°C. Charge DCM (5.98 kg ± 5% or 4.50 L ± 5%) into the batch while maintaining a temperature of approximately 15-30° C. In some cases, the mixture remains cloudy even though complete dissolution of compound 6a is achieved.

[0319] While maintaining a temperature of about 20-25°C, compound 6a species (0.02 kg ± 2%) is charged to the batch solution. Crystallization is observed, but the rate of crystallization may be slow. The mixture is mixed at a temperature of about 20-25°C for about 1-2 hours until a slurry appears. If a slurry is not observed, the mixture is cooled to a temperature of about 15-20°C, and additional compound 6a species (0.02 kg ± 2%) is added to the batch solution while maintaining a temperature of about 15-20°C for about 1 to about 2 hours, after which a slurry appears. Lowering the temperature during and after seed addition may result in higher yields at the expense of lower purity.

[0320] The batch is cooled to about 15-25°C and stirred at this temperature range for about 18-24 hours. The batch is cooled to a temperature of about 5°C to about -5°C over about 1-12 hours and held at this temperature range with stirring for about 6-12 hours. In certain embodiments, the batch is cooled to a temperature of about 5°C to about 5°C over about 2 hours and held at this temperature range with stirring for about 6-12 hours. This aging time is critical to yield. The batch is drained into a suitable filter and deliquored. The wet cake is washed with a DCM solution (1.33 kg ± 5% or 1.00 L ± 5%) at about 5°C to -5°C, followed by deliquoring. The product is dried under vacuum at about 45°C or below (e.g., 0-45°C). Drying is complete when the loss on drying is about 1% w / w or less. The product may be dried under vacuum with a nitrogen blast. The product may be sieved after the drying operation. The yield over two steps from compound 4a to compound 6a is approximately 85%. Severity of some of the variations, such as the final volume of distillation, amount of DCM, water content, seeding and aging temperature, and post-seeding aging time, can provide typical crystallization with typical purity results. Water may affect yield, but does not appear to be related to product quality.

[0321] Part 3: Optimization of crystallization conditions for compound 6a The solubility of compound 6a in dichloromethane / isopropyl acetate (50 / 50 v / v) containing approximately 1% water, isopropyl acetate / dichloromethane (71 / 29 v / v) containing approximately 2% water, and isopropyl acetate / dichloromethane (71 / 29 v / v) containing approximately 8% water shows a strong dependence on temperature. At elevated temperatures, limited solubility can be observed in dichloromethane / isopropyl acetate (50 / 50 v / v) containing approximately 1% water, while moderate solubility can be observed in isopropyl acetate / dichloromethane (71 / 29 v / v) containing approximately 2% water and isopropyl acetate / dichloromethane (71 / 29 v / v) containing 8% water. The cloud point occurs when the reactor reaches a minimum temperature of approximately 6-8 °C, indicating a large metastable zone under all conditions. At approximately 7.9 mg / mL in dichloromethane / isopropyl acetate (50 / 50 v / v) containing approximately 1% water, the cloud point does not occur until approximately 3 and 8 hours at approximately 6-8 °C. These results indicate that without the use of seeding, inconsistencies in the timing of the primary nucleation event (spontaneous nucleation) can be expected. Furthermore, nucleation consistently occurs at high supersaturation levels, sometimes resulting in low crystallinity, crystalline defects such as solvent inclusion, and / or the formation of small particles.

[0322] Selected samples from each solvent system from the solubility and metastable zone width determination experiments were isolated by vacuum filtration. No filtration problems were observed when the solids were isolated from dichloromethane / isopropyl acetate (50 / 50 v / v) containing approximately 1% water. However, sticky solids and some deliquescence were observed from solids isolated from isopropyl acetate / dichloromethane (71 / 29 v / v) containing both approximately 2% and approximately 8% water. Material isolated from dichloromethane / isopropyl acetate (50 / 50 v / v) containing approximately 1% water was crystalline. Material isolated from isopropyl acetate / dichloromethane (71 / 29 v / v) containing approximately 2% water was irregular, and material isolated from isopropyl acetate / dichloromethane (71 / 29 v / v) containing approximately 8% water may contain a small amount of x-ray amorphous material.

[0323] Part 4: Characterization data for compound 6a The XRPD spectrum of compound 6a is shown in Figure 4, with peak positions substantially following those listed in Table 1. The TGA of compound 6a showed a 4.5 wt% loss between 24.1 and 78.6 °C (Figure 5). The main exothermic event in the DSC of compound 6a occurred at a left limit temperature of 231.8 °C and an energy of -52.9 kJ / kg (Figure 6).

[0324] Example 3: Synthesis protocol for compound 7a A general synthetic protocol for compound 7a is detailed below. Part 1: Synthesis of compound 7a [ka]

[0325] Charge compound 6a (1.0 kg ± 1%) and acetonitrile (3.94 kg ± 5% <> 5.00 L ± 5%) into a reactor. Allow the temperature to stabilize at about 15°C to about 30°C while mixing. The solution may be cloudy. Distill the mixture under vacuum at a maximum temperature of about 45°C (e.g., 20-45°C) to a final volume of 2 L ± 5%.

[0326] Take a sample for determination of water content by Karl Fischer. If the water content is less than about 0.30% w / w, proceed to the next step. Otherwise, charge acetonitrile (2.36 kg ± 5% <> 3.00 L ± 5%) to the reactor and repeat the distillation until the water content in the solution after distillation is below approximately 0.30% w / w by Karl Fischer.

[0327] Cool the reaction mixture to a temperature of about 30°C to about 15°C and charge acetone (3.94 kg ± 5% <> 5.00 L ± 5%) to the reactor. A portion of the acetone may be charged after the sodium bicarbonate and / or 2-iodoethanol charge and used to rinse the charge system used for these charges.

[0328] The reaction mixture is heated to a temperature of about 33°C to about 37°C (target is about 35°C). Sodium bicarbonate (0.177 kg ± 2%) is charged to the reactor while maintaining the reaction mixture temperature at about 33°C to about 37°C (target is about 35°C). 2-iodoethanol (0.226 kg ± 2% <> 0.102 L ± 2%) is charged to the reaction mixture while maintaining the reaction mixture temperature at about 33°C to about 37°C (target is about 35°C). The reaction mixture is mixed at a temperature of about 33°C to about 37°C (target is about 35°C) until the content of compound 6a relative to compound 7a is about 2.5% or less by area by HPLC. Additional 2-iodoethanol is added to the reaction mixture if necessary to complete the reaction. The amount of additional 2-iodoethanol in kg is calculated using the following formula: [P2 x D / (100 - D)] ± 2%, where P2 is the amount of 2-iodoethanol in kg initially charged during the reaction, and D is the content of unconsumed compound 6a in the final in-process control sample in % area by HPLC. The area percent is determined by HPLC-UV: Zorbax SB-CN, 3.5 μm, 150 x 4.6 mm, A: 25 mM K2HPO4; B: acetonitrile, gradient: 5 to 80% B in 25 min, hold for 5 min; re-equilibrate for 5 min, flow rate: 1.0 mL / min, UV: 210 nm, column temperature: 30 °C.

[0329] Upon completion, the reaction mixture is cooled to a temperature of about 25°C to about 20°C. While maintaining a temperature of about 20°C to about 25°C, 1,4-diazabicyclo[2.2.2]octane (DABCO, 0.24 kg ± 2%) is charged to the reaction mixture and mixed at this temperature range until the content of 2-iodoethanol by GC is lower than the loss on drying for the method (<0.003% w / w). The GC method uses a 50 cm DB-1 column with a 0.32 mm ID. The initial oven temperature is about 70°C and held for about 1 minute, followed by a gradient of about 10°C / min to about 250°C. Deionized water (5.00 kg ± 5% <> 5.00 L ± 5%) is added to the mixture while maintaining a temperature of about 15°C to about 30°C. This addition is exothermic. While maintaining a temperature of about 15°C to about 30°C, isopropyl acetate (4.36 kg ± 5% <> 5.00 L ± 5%) is added and the mixture is mixed for about 5 minutes to 12 hours at a temperature of about 15°C to about 30°C. In certain embodiments, while maintaining a temperature of about 15°C to about 30°C, isopropyl acetate (4.36 kg ± 5% <> 5.00 L ± 5%) is added and the mixture is mixed for about 20 minutes or more at a temperature of about 15°C to about 30°C. Mixing is then stopped and the layers are allowed to separate for about 30 minutes to 12 hours. In certain embodiments, mixing is then stopped and the layers are allowed to separate for at least about 30 minutes or more. Aqueous Phase 1 (the lower phase) is drained and Organic Phase 1 is drained into a receiver. The product is in the organic phase.

[0330] Add isopropyl acetate (2.62 kg ± 5% <> 3.00 L ± 5%) to Aqueous Phase 1 and mix the mixture for about 15 minutes to 12 hours at a temperature of about 15°C to about 30°C. In certain embodiments, add isopropyl acetate (2.62 kg ± 5% <> 3.00 L ± 5%) to Aqueous Phase 1 and mix the mixture for about 20 minutes or more at a temperature of about 15°C to about 30°C. Stop mixing and allow the layers to separate for at least about 30 minutes or more (e.g., 30 minutes to 12 hours). Discard Aqueous Phase 2 (the lower phase) for disposal. Discard Organic Phase 2 into a receiver. The product is in the organic phase; combine Organic Phases 1 and 2.

[0331] Aqueous sodium chloride solution is prepared by dissolving sodium chloride (technical) (2.00 kg ± 1%) in deionized water (5.80 kg ± 5% <> 5.80 L ± 5%). Approximately 2-6 L of aqueous sodium chloride solution is charged to the combined organic phases, and the mixture is mixed for approximately 15 minutes to 12 hours at a temperature of about 15°C to about 30°C. In certain embodiments, approximately 3 L of aqueous sodium chloride solution is charged to the combined organic phases, and the mixture is mixed for approximately 20 minutes or more at a temperature of about 15°C to about 30°C. Mixing is stopped, and the layers are allowed to separate for approximately 15 minutes to 12 hours. In certain embodiments, mixing is stopped, and the layers are allowed to separate for at least approximately 30 minutes or more. Aqueous Phase 3 (the lower phase) is discharged to waste. Organic Phase 3, containing the product, is discharged into a receiver.

[0332] About 2-6 L of aqueous sodium chloride solution is charged to the combined organic phases, and the mixture is mixed for about 15 minutes to 12 hours at a temperature of about 15°C to about 30°C. In certain embodiments, about 3 L of aqueous sodium chloride solution is charged to the combined organic phases, and the mixture is mixed for about 20 minutes or more at a temperature of about 15°C to about 30°C. Mixing is stopped, and the layers are allowed to separate for at least about 30 minutes or more (e.g., 30 minutes to 12 hours). Aqueous Phase 4 (the lower phase) is discharged to waste. Organic Phase 4, containing the product, is discharged into a receiver.

[0333] Distill the organic phase under vacuum to a final volume of 2 L ± 5% at a maximum jacket temperature of approximately 20-50°C (e.g., 50°C). Charge acetonitrile (8.03 kg ± 5% <> 10.20 L ± 5%) to the mixture, and distill the mixture under vacuum to a final volume of 7.2 L ± 5% at a maximum jacket temperature of approximately 20-50°C (e.g., 50°C). Charge isopropyl acetate (0.70 kg ± 5% <> 0.80 L ± 5%) and deionized water (0.095 kg ± 2% <> 0.095 L ± 2%) to the solution, and heat the solution to a temperature of approximately 70°C to approximately 80°C to ensure complete dissolution of Compound 7a.

[0334] The solution of compound 7a is cooled to a temperature of about 65°C to about 60°C. If crystallization occurs before the addition of seeds, the mixture can be heated again to a temperature of about 70°C to about 80°C until complete dissolution. Before adding seeds, the mixture is cooled to a temperature of about 65°C to about 60°C. Compound 7a seeds (0.02 kg ± 5% kg) are charged to the solution of compound 7a while maintaining a temperature of about 60°C to about 65°C. The charging system used to charge compound 7a seeds is rinsed with acetonitrile (0.04 kg ± 5% <> 0.05 L ± 5%) and the rinse is added to the reaction mixture. The mixture is mixed at a temperature of about 60°C to about 65°C for about 4 to about 6 hours. A very thick suspension is formed.

[0335] The mixture is cooled to a temperature of about 5°C to about 0°C over about 12 hours and mixed at this temperature range for about 1 to about 2 hours. The target cooling rate is about 5-10°C / hour. The product is filtered and washed with acetonitrile (2.83 kg ± 5% <> 3.60 L ± 5%) pre-cooled to a temperature of about 0°C to about 5°C. The product is then dried under vacuum at a temperature of about 45°C or less (e.g., 0-45°C) until the loss on drying is about 1% w / w or less. The product is dried with a nitrogen blast. The product can be sieved during or after drying. The yield of compound 7a is about 90%.

[0336] Part 2: Optimization of 6' amine alkylation with haloethanols After testing several conditions for 6' amino alkylation, azeotropic distillation of ACN was selected, followed by the addition of acetone, 2-iodoethanol, and sodium bicarbonate, and quenching the reaction using DABCO.

[0337] Two approaches to alkylating 6' amines with haloethanols were initially investigated. In the first approach, the 6' amine was activated using o-nitrobenzenesulfonyl chloride (nosyl-Cl) to give the corresponding 6' amino nosylate. Subsequent alkylation of the nosylate with 2-iodo or 2-bromoethanol gave the corresponding 6' amino nosylate. The conversion was not optimal with or without TBDMS hydroxyl protection and showed little improvement with changes in solvent (e.g., THF, ACN, or DMF), base (e.g., DIPEA or K2CO3), and temperature (e.g., ambient to approximately 80 °C). A second approach, direct 6' amine alkylation using 2-bromoethanol in the presence of NaI and Na2CO3 at ambient temperature, potentially afforded more complete conversion and a cleaner crude product. 2-bromoethanol, sodium iodide, and sodium carbonate conditions were selected for further evaluation and development.

[0338] Approximately 2 to 3 molar equivalents of 2-bromoethanol were found to improve the reaction conditions, with slightly less dialkylated by-product formed at approximately 2 equivalents. The conversion range was approximately 51 to 68%, with approximately 1 to 2 equivalents of NaI required to achieve conversions greater than 65%. However, bromoethanol and sodium iodide were identified as possible significant contributors of water to the reaction mixture. Water in the reaction mixture was suboptimal for the results and may correlate with higher levels of dialkylated by-product. Compound 6a potentially contributed significant water to the batch, but this could be removed by azeotropic distillation with acetonitrile. Other azeotropic solvents, such as ethanol or isopropanol, which subsequently affected the product precipitate, were potentially less effective. Acetone was identified as a possible preferred solvent for the alkylation reaction. Without being limited by theory, a potential acetoneiminium intermediate that could have prevented the alkylation was hypothesized based on LC / MS evidence. Without being limited by theory, it is possible that water in the batch inhibited the formation of this hypothesized imine or destabilized the imine, thereby allowing the formation of dialkylated by-products. Without being limited by theory, the role of sodium carbonate as a drying agent may be important, as it results in higher yields than lithium carbonate, potassium carbonate, cesium carbonate, sodium bicarbonate, sodium sulfate, sodium phosphate, and DIPEA. A reaction temperature of about 35°C resulted in the greatest relative degree of conversion with the least relative amount of dialkylated by-products compared to about -10°C, about 0°C, and about 23°C. A higher reaction temperature (e.g., about 50°C) may result in the formation of more dialkylated by-products.

[0339] However, bromoethanol and sodium iodide may be the main contributors of water in the reaction mixture, leading to the formation of by-products. 2-iodoethanol was also tested and used to generate 2-iodoethanol in situ. Bromoethanol also resulted in a much slower reaction than 2-iodoethanol. The use of approximately 1.2 molar equivalents of 2-iodoethanol in acetone was sufficient to obtain approximately 86% yield of compound 7a at approximately 35 °C in approximately 24 hours, with only approximately 2% of compound 6a and approximately 2.6% of dialkylated impurities. The use of approximately 1.1 molar equivalents of 2-iodoethanol yielded approximately 83% yield of compound 7a, approximately 6.9% of compound 6a, and approximately 1.5% of dialkylated impurities. The use of approximately 1.5 molar equivalents of 2-iodoethanol yielded approximately 87% yield of compound 7a, with approximately 1.9% of compound 6a and approximately 2.3% of dialkylated impurities. Longer reaction times (approximately 41 or 48 hours) may result in the reduction of compound 7a without further consuming compound 6a. NaHCO3 was tested as a base for the reaction and may be preferable to Na2CO3, Na2SO4, trimethylamine, trimethyl orthogonate, and hexamethyldisilazane. Na2CO3 resulted in a relatively higher final pH and higher amounts of dialkylated by-products at the end of the reaction compared to NaHCO3 and Na2SO4, while Na2SO4 resulted in the generation of new impurities in the isolated product. Other scavengers tested, such as dimethylamine, trimethylamine, diethanolamine, aqueous sodium hydroxide, DBU, cysteine, and MeOH, showed increases in dialkylated by-products of approximately 63-1030% in process and isolated product levels, suggesting that residual 2-iodoethanol cannot be destroyed, so DABCO is recommended. , may be a preferred quenching agent for excess 2-iodoethanol.

[0340] Azeotropic drying of compound 6a in approximately 5 volumes of ACN was found to work well for amine alkylation reactions using acetone, 2-iodoethanol, and sodium bicarbonate, followed by DABCO to quench the reaction. Using approximately 5 volumes of acetone, NaHCO3, and approximately 1.2 molar equivalents of 2-iodoethanol at a reaction temperature of approximately 2-40°C, yields of less than 2% of compound 6a were achieved, along with low levels of dialkylated by-products. In certain embodiments, using approximately 5 volumes of acetone, NaHCO3, and approximately 1.2 molar equivalents of 2-iodoethanol at a reaction temperature of approximately 35°C, yields of less than 2% of compound 6a were achieved, along with low levels of dialkylated by-products. Furthermore, it was found that the quality of compound 7a prepared using a simplified workup with brine and no acid and base extractions could be superior to that obtained using a lengthy workup with acid and base extractions. Also, replacing the water wash with a brine wash correlated with an increase in molar yield of about 15 percent without any loss in product quality.

[0341] Part 3: Optimization of crystallization conditions for compound 7a Several crystallization procedures were tested prior to the crystallization of crude compound 7a from approximately 8 volumes of 10% v / v IPAc / ACN with approximately 0.75–2% w / w water, accompanied by seeding (see Tables 7–11). Furthermore, a long hold time at the seeding temperature (approximately 60–65°C for over 2 hours) and a slow cooling gradient (approximately 5–10°C / hour decreasing from approximately 60°C to approximately 0°C) may be optimal for obtaining a fluid slurry. This procedure may adequately remove unreacted compound 6a, the penta-Boc impurity (approximately 63% removal combined), and the dialkylated by-product (approximately 36% removal), providing an easily filterable and washable solid product. Because the product formed needle- or rod-like crystals, the deliquoring properties of crystalline compound 7a from IPAc / ACN may improve the removal of impurities in the mother liquor. In contrast, experiments using IPAc and n-heptane produced amorphous material that was filtered and slowly deliquored, leaving the impurities in the product. [Table 7] (a) Thick, immiscible slurry. Additional solvent (typically 5 volumes) was added to allow filtration. [Table 8-1] [Table 8-2] (a) Slurry (b) Acetonitrile and heptane are immiscible at room temperature. (c) Thick, unstirrable slurry. Additional solvent (typically 5 volumes) was added to allow filtration. (d) Solid Compound 7a was added but did not act as a seed. (e) Upon crystallization, crystals formed over 4 hours, then heated to near reflux to dissolve the solid. The solution was cooled to room temperature and mixed for 15 hours before the solid was collected. When the crystallization process was allowed to cool slowly, the resulting product had a thin, needle-like morphology. [Table 9-1] [Table 9-2] (a) Mass of solids in a 1 L reactor. [Table 10-1] [Table 10-2] (a) Water content adjusted to 0.5%, (b) Water content adjusted to 1%, (c) Water content adjusted to 2.7%, (d) Three temperature cycles: 65–40, 70–40, 70–0; the crystals formed were “rod-shaped”, (e) Dry seeds used, (f) “rod-shaped” (not needle-shaped) compound 7a was seeded. [Table 11-1] [Table 11-2] (A) Water content adjusted to approximately 0.3%, (b) Water content adjusted to 0.5%, (c) Low recovery likely due to improper adjustment of water content, (D) Water content adjusted to 3.5%. This entry used a brine wash procedure instead of the acid / base workup to check for product loss and reagent removal. Other entries in the table use a water wash instead of the acid / base workup. Only the cleaning procedure was used.

[0342] Water content can be important in controlling the robustness of crystallization. Approximately 0–2% water was added to determine a variable metastable zone. An "anhydrous" run with approximately 0% water (approximately 0.2–0.3% water content) resulted in a broad metastable zone with a clearing point at approximately 55–60°C and a cloud point below ambient temperature (approximately 8–15°C). Adding approximately 0.5–2% water significantly narrowed the metastable zone, with a clearing point at higher temperatures. This observation suggested that a certain level of water in the mixture (initially approximately 0.5–1%) could make crystallization more reproducible and robust. Karl Fischer water determination after the azeotropic solvent exchange from IPAc to ACN during workup of compound 6a to compound 7a indicated that the solution was nearly dry (approximately 200 ppm water), so the crystallization performed after azeotropic drying was operated in an anhydrous mode with a very broad metastable zone. This results in very slow desaturation, which may increase the chances of spontaneous nucleation. Crystallization with about 0.5-2% added water can be more reproducible, with consistent recoveries (generally above about 80%) and higher purity.

[0343] Part 4: Characterization data for compound 7a The XRPD spectrum of compound 7a is shown in Figure 7, with peak positions substantially in accordance with those listed in Table 2. The TGA profile of compound 7a is shown in Figure 8. The DSC profile of compound 7a is shown in Figure 9. Example 4: Synthesis of Plazomycin Sulfate [ka] Part 1: Synthesis of compound 8a [ka]

[0344] Compound 7a (1.0 kg ± 1%, 1.00 mol) is charged to a reactor. Dichloromethane (5.0 L ± 5%) is charged and the mixture is cooled to about 0-5°C. Trifluoroacetic acid (TFA, 3.0 L ± 5%, 39.5 mol) is charged to the mixture at a rate that maintains a temperature of about 0-5°C. The mixture is then heated to about 20-25°C and mixed for about 1-2 hours. The mixture is distilled under vacuum to a final volume of 3 L ± 5% while maintaining a reactor jacket temperature of about 20-40°C. In certain embodiments, the mixture is then distilled under vacuum to a final volume of 3 L ± 5% while maintaining a reactor jacket temperature of about 30°C. The mixture is then cooled to about 20-25°C, and then mixed for about 1-4 hours before being cooled to about 0-10°C. The resulting solution is then charged to a reactor charged with water (about 2.5 L, pre-cooled to about 0-5°C) while maintaining a temperature of about 0-10°C.

[0345] The reactor is charged with isopropyl acetate (IPAc, 3.0 L ± 5%), and the mixture is mixed for about 20-30 minutes, after which mixing is stopped and the layers are allowed to separate. The organic phase is extracted twice by draining the lower aqueous layer (aqueous phase 1) and charging with water (about 0.5 L ± 5%). The mixture is mixed for about 15 minutes to 12 hours, after which mixing is stopped and the layers are allowed to separate. In certain embodiments, the lower aqueous layer (aqueous phase 1) is drained and the organic phase is extracted twice by charging with water (about 0.5 L ± 5%). The mixture is mixed for about 30 minutes, after which mixing is stopped and the layers are allowed to separate. Each lower aqueous layer (aqueous phase 2 and 3) is collected and combined with aqueous phase 1. The combined aqueous phase is then washed three times with IPAc, and the TFA is removed by charging IPAc (3.0 L ± 5%) and mixing for about 20-30 minutes, after which mixing is stopped and the layers are allowed to separate. Drain the bottom aqueous phase and measure the pH to ensure it is >2.0 If the pH is below 2.0, repeat the IPAc wash until the pH is above about 2.0. Part 2: Synthesis of plazomycin sulfate [ka]

[0346] The aqueous phase of Part 1 is then diluted with water to a final volume of 9.0 L ± 5% and treated with aqueous ammonia (prepared by diluting about 25% ammonia (4 kg ± 5%) in water (96 kg ± 5%)) until the pH is between about 5.8 and about 6.2. The conductivity is measured to ensure that the conductivity is about 20 mS / cm or less (e.g., 0-20 mS / cm). If the conductivity is greater than 20 mS / cm, additional water is added to achieve a conductivity of about 20 mS / cm or less (e.g., 0-20 mS / cm).

[0347] The crude Compound 8a TFA salt solution is purified by ion exchange chromatography by loading the solution onto an ion exchange column containing Amberlite CG-50 (type 1) resin (2.17 kg) previously converted to the ammonia form. The column is eluted with water (1 column volume ± 5%) to elute the ammonium trifluoroacetate, followed by aqueous ammonia (prepared by diluting approximately 25% ammonia (2.0 kg ± 5%) in water (96.0 kg ± 5%)). The chromatography is monitored by UV absorption. Fractions are collected and analyzed by UPLC, and fractions containing greater than approximately 95% (by area) of Compound 8a free base (compound without TFA salt) are pooled.

[0348] The combined chromatographic fractions were passed through a filter (porosity ≦5 microns) and the filter was rinsed with water (1 L ± 5%). The resulting solution was concentrated to a final volume of 16 L ± 5% by nanofiltration through a Dow Filmtec XLE membrane, maintaining a temperature of approximately 0-10°C. Ammonia was then removed by dialysis through a Dow Filmtec XLE membrane.

[0349] Cool the solution of compound 8a free base to approximately 0-5 °C and treat with aqueous sulfuric acid (prepared by dissolving pure sulfuric acid (0.51 kg ± 5%) in DI water (0.72 L ± 5%)) until the pH reaches approximately 6.0-6.5. Pass the resulting plazomycin sulfate solution through an activated charcoal filter (R55SP) and wash the filter with water.

[0350] The solution is concentrated by nanofiltration using a Dow Filmtec XLE membrane and then filtered through a 0.22 micron filter. The resulting solution is then fed into a spray dryer while maintaining the outlet temperature at approximately 60-100°C to recover plazomycin sulfate as an amorphous solid. Example 5: Example of a procedure for the preparation of 4-nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-((((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutamido)-3-((((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, formula (4a), from sisomicin. [ka]

[0351] Example 5a A jacketed glass reactor equipped with an overhead stirrer was charged with sisomicin free base (300.0 g, 0.670 mol, KF = 5.65), followed by methanol (1500 mL) and dichloromethane (1500 mL). After dissolution, the reaction temperature was stabilized at 15 °C. A solution of p-nitrobenzyl benzotriazole carbamate (207 g, 0.694 mol, 1.04 equiv.) in dichloromethane (4200 mL) was added to the reactor over 3 hours, maintaining the reaction temperature at approximately 15 °C. The addition was completed with a dichloromethane (300 mL) rinse. After 30 minutes, the reaction was sampled and deemed complete by HPLC analysis (sisomicin consumption). The crude reaction mixture was concentrated under vacuum to a final volume of 1500 mL. Methanol (4500 mL) was charged to the reaction mixture, and a second concentration under vacuum was performed to a volume target of 4500 mL.

[0352] Methanol (900 mL) was charged to the reaction mixture and the temperature was allowed to stabilize at 27.5 °C. Triethylamine (442 mL, 3.189 mol, 4.76 eq) and zinc acetate dihydrate (487 g, 2.219 mol, 3.31 eq) were charged sequentially and the mixture was mixed for 1 hour. A previously prepared solution of di-tert-butyl-dicarbonate (759 g, 3.478 mol, 5.19 eq) in methanol (600 mL) was added to the reaction solution over 70 minutes. The transfer was completed with a methanol (60 mL) rinse. After the addition, the reaction was mixed at 27.5 °C for 9.5 hours, at which point the reaction was sampled and analyzed by HPLC (4-nitro). nitrobenzyl (((2S,3R)-3-amino-2-(((1R,2S,3S,4R,6S)-4,6-diamino-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, and the mono-Boc protected intermediate = 4-nitrobenzyl ( The reaction mixture was deemed complete with ((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-4,6-diamino-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate). The crude reaction mixture was concentrated under vacuum to a final volume of 3600 mL. The temperature was allowed to stabilize at 20-30°C and the reaction was quenched by the addition of 25% ammonia (1800 mL) over 1.5 hours (Caution: addition is exothermic, addition rate was controlled to maintain a reaction temperature of 20-30°C). Dichloromethane (3000 mL) was added, and the biphasic mixture was mixed for 20 minutes, after which stirring was stopped and the layers were allowed to separate. The lower, product-rich organic layer (OP1) was transferred to a receiver, and the upper, depleted aqueous layer (AQ1) was transferred to waste. OP1 was returned to the reactor charged with water (750 mL) and 25% ammonia (750 mL). The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP2) was transferred to a receiver, and the upper aqueous layer (AQ2) was transferred to waste. OP2 was returned to the reactor charged with methanol (300 mL) and water (1500 mL). The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP3) was transferred to a receiver, and the upper aqueous layer (AQ3) was transferred to waste. OP3 was returned to the reactor charged with methanol (300 mL) and water (1500 mL). The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP4) was transferred to a receiver and the upper aqueous layer (AQ4) was transferred to waste. The final washed organic phase (OP4) was returned to the reactor and concentrated under vacuum to a volume of 2700 mL.

[0353] Water (150 mL), Boc-(S)-HABA (153 g, 0.698 mol, 1.04 equiv.), and 1-hydroxybenzotriazole (17 g, 0.125 mol, 0.19 equiv.) were added to the reactor. After each solid charge (Boc-(S)-HABA and 1-hydroxybenzotriazole), dichloromethane (60 mL) was used to rinse the charging system. The pH of the reaction mixture was adjusted to 5.5 using 2 M hydrochloric acid (1250 mL). After the pH adjustment, 1-ethyl-3-(3'dimethylaminopropyl)carbodiimide hydrochloride (133 g, 0.694 mol, 1.03 equiv.) was charged to the reaction mixture. Dichloromethane (60 mL) was used to rinse the solid charge. After 70 minutes, the reaction was sampled and deemed complete by HPLC (consumption of 4-nitrobenzyl(((2S,3R)-2-(((1R,2R,3S,4R,6S)-4-amino-6-((tert-butoxycarbonyl)amino)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-6-yl)met). Methanol (600 mL) was charged to the reaction mixture, followed by dichloromethane (3600 mL) and water (1500 mL). Sodium hydroxide (1200 mL) was used. The pH was adjusted to 9.5 by stirring. The layers were mixed by stirring and then allowed to separate, after which the lower product-rich organic layer (OP5) was transferred to a receiver and the upper aqueous layer (AQ5) was transferred to waste. OP5, followed by water (2100 mL), was returned to the reactor. The layers were mixed by stirring and then allowed to separate, after which the lower product-rich organic layer (OP6) was transferred to a receiver and the upper aqueous layer (AQ6) was transferred to waste. OP6 was returned to the reactor and concentrated under vacuum to a final volume of 3000 mL. Acetonitrile (3000 mL) was charged to the reactor and the mixture was concentrated under vacuum to a final volume target of 3000 mL. Acetonitrile (3000 mL) was charged to the reactor and the mixture was concentrated under vacuum to a final volume target of 3000 mL. Acetonitrile (approximately 4500 mL) was charged to the reaction mixture to a final volume target of 7500 mL.

[0354] The mixture was heated to reflux (83° C.) and two portions of water (75 mL and 38 mL) were added sequentially to form a solution. The solution was cooled to 75° C., after which 4-nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, Formula (4a), seed (3 g, 0.0029 mol, 0.004 equivalents) was charged to the reaction mixture. The newly formed slurry was cooled to 3°C over 5 hours and mixed at 0-5°C for an additional 4 hours. The mixture was filtered, washed with acetonitrile (two portions of 300 mL), and dried under vacuum to give 4-nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, Formula (4a), (345.19 g, molar yield 50%).

[0355] Example 5b A jacketed glass reactor equipped with an overhead stirrer was charged with sisomicin free base (300.0 g, 0.670 mol, 1 equiv., KF = 5.65), followed by methanol (1500 mL) and dichloromethane (1500 mL). After dissolution, the reaction temperature was allowed to stabilize at 15 °C. A solution of p-nitrobenzyl benzotriazole carbamate (207 g, 0.694 mol, 1.04 equiv.) in dichloromethane (4200 mL) was added to the reactor over 3 hours, maintaining the reaction temperature at approximately 15 °C. The addition was completed with a dichloromethane (300 mL) rinse. After 30 minutes, the reaction was sampled and deemed complete by HPLC analysis (sisomicin consumption). The crude reaction mixture was concentrated under vacuum to a final volume of 1500 mL.

[0356] Methanol (4500 mL) was charged to the reaction mixture and the temperature was allowed to stabilize at 20 °C. Triethylamine (498 mL, 3.593 mol, 5.36 eq) and zinc acetate dihydrate (425 g, 1.935 mol, 2.89 eq) were charged sequentially, and the mixture was mixed for 1 hour. A previously prepared solution of di-tert-butyl-dicarbonate (894 g, 4.096 mol, 6.11 eq) in methanol (600 mL) was added to the reaction solution over 80 minutes. A methanol (60 mL) rinse completed the transfer. After the addition, the reaction was mixed at 20° C. for 5 hours, at which time the reaction was sampled and analyzed by HPLC (4-nitrobenzyl(((2S,3R)-3-amino-2-(((1R,2S,3S,4R,6S)-4,6-diamino-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, and The reaction was deemed complete upon consumption of the mono-Boc protected intermediate 4-nitrobenzyl(((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-4,6-diamino-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate. Crude reaction mixture The mixture was concentrated under vacuum to a final volume of 3000 mL. The temperature was stabilized at 20-30 °C and the reaction was quenched by the addition of 25% ammonia (1500 mL) over 1.5 hours (Caution: The addition was exothermic; the addition rate was controlled to maintain a reaction temperature of 20-30 °C). Dichloromethane (3000 mL) was added and the biphasic mixture was mixed; then, stirring was stopped and the layers were allowed to separate. The lower, product-rich organic layer (OP1) was transferred to a receiver, and the upper, depleted aqueous layer (AQ1) was transferred to waste. OP1 was returned to the reactor, which had been charged with water (750 mL) and 25% ammonia (750 mL). The layers were mixed by stirring and then allowed to separate; then, the lower, product-rich organic layer (OP2) was transferred to a receiver, and the upper aqueous layer (AQ2) was transferred to waste. OP2 was returned to the reactor, which had been charged with methanol (225 mL) and water (1500 mL). The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP3) was transferred to a receiver and the upper aqueous layer (AQ3) was transferred to waste. OP3 was returned to the reactor, which was charged with methanol (225 mL) and water (1500 mL). The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP4) was transferred to a receiver and the upper aqueous layer (AQ4) was transferred to waste. The final washed organic phase (OP4) was returned to the reactor and concentrated under vacuum to a volume of 2700 mL.

[0357] Water (150 mL), Boc-(S)-HABA (153 g, 0.698 mol, 1.04 equiv.), and 1-hydroxybenzotriazole (17 g, 0.126 mol, 0.19 equiv.) were added to the reactor. After each solid (Boc-(S)-HABA and 1-hydroxybenzotriazole) was charged, dichloromethane (60 mL) was used to rinse the charging system. The pH of the reaction mixture was adjusted to 6.2 using 2 M hydrochloric acid (1098 mL). After the pH adjustment, 1-ethyl-3-(3'dimethylaminopropyl)carbodiimide hydrochloride (133 g, 0.694, 1.03 equiv.) was charged to the reaction mixture. Dichloromethane (60 mL) was used to rinse the solid charge. After 2 hours, the reaction was sampled and deemed complete by HPLC (consumption of 4-nitrobenzyl(((2S,3R)-2-(((1R,2R,3S,4R,6S)-4-amino-6-((tert-butoxycarbonyl)amino)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-6-yl)met). Methanol (525 mL) was charged to the reaction mixture, followed by dichloromethane (3600 mL) and water (1500 mL). The pH was adjusted to 8.5 using sodium hydroxide (365 mL). The layers were stirred. The mixture was mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP5) was transferred to a receiver and the upper aqueous layer (AQ5) was transferred to waste. OP5, followed by water (2100 mL), was returned to the reactor. The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP6) was transferred to a receiver and the upper aqueous layer (AQ6) was transferred to waste. OP6 was returned to the reactor and concentrated under vacuum to a final volume of 3000 mL. Acetonitrile (3000 mL) was charged to the reactor and the mixture was concentrated under vacuum to a final volume target of 3000 mL. Acetonitrile (3000 mL) was charged to the reactor and the mixture was concentrated under vacuum to a final volume target of 3000 mL. Acetonitrile (approximately 6000 mL) was charged to the reaction mixture to a final volume target of 9000 mL.

[0358] The mixture was heated to reflux (83°C) and two portions of water (75 mL and 38 mL) were added sequentially to form a solution. The solution was cooled to 75°C and then 4-nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate , Formula (4a), seeds (3 g, 0.0029 mol, 0.004 equiv.) were charged to the reaction mixture. The newly formed slurry was cooled to 3 °C over 5 h and stirred at 0-5 °C for an additional 4 h. The mixture was filtered, washed with acetonitrile (two portions of 300 mL), and dried under vacuum to give 4-nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, Formula (4a), (340.68 g, molar yield 49%).

[0359] Example 5c A jacketed glass reactor equipped with an overhead stirrer was charged with sisomicin free base (300.0 g, 0.670 mol, 1 equiv., KF = 5.65), followed by methanol (1500 mL) and dichloromethane (1500 mL). After dissolution, the reaction temperature was allowed to stabilize at 15 °C. A solution of p-nitrobenzyl benzotriazole carbamate (189 g, 0.664 mol, 0.99 equiv.) in dichloromethane (4200 mL) was added to the reactor over 3 hours, maintaining the reaction temperature at approximately 15 °C. The addition was completed with a dichloromethane (300 mL) rinse. After 29 minutes, the reaction was sampled and deemed complete by HPLC analysis (sisomicin consumption). The crude reaction mixture was concentrated under vacuum to a final volume of 1500 mL. Methanol (4500 mL) was charged to the reaction mixture and a second concentration was performed under vacuum to a volume target of 4500 mL.

[0360] Methanol (900 mL) was charged to the reaction mixture and the temperature was allowed to stabilize at 35°C. Triethylamine (385 mL, 2.777 mol, 4.14 eq) and zinc acetate dihydrate (549 g, 2.501 mol, 3.73 eq) were charged sequentially, and the mixture was mixed for 1 hour. A previously prepared solution of di-tert-butyl-dicarbonate (620 g, 2.841 mol, 4.24) in methanol (600 mL) was added to the reaction solution over 60 minutes. A methanol (60 mL) rinse completed the transfer. After the addition, the reaction was mixed at 35° C. for 5 hours, at which point the reaction was sampled and analyzed by HPLC (4-nitrobenzyl(((2S,3R)-3-amino-2-(((1R,2S,3S,4R,6S)-4,6-diamino-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, and The reaction was deemed complete upon consumption of the mono-Boc protected intermediate, 4-nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-4,6-diamino-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate. The crude reaction mixture was concentrated under vacuum to a final volume of 4200 mL. The temperature was stabilized at 20-30 °C and the reaction was quenched by the addition of 25% ammonia (2100 mL) over 1 hour 27 minutes (Caution: addition is exothermic; addition rate was controlled to maintain the reaction temperature at 20-30 °C). Dichloromethane (3000 mL) was added and the biphasic mixture was mixed for 20 minutes, after which stirring was stopped and the layers were allowed to separate. The lower, product-rich organic layer (OP1) was transferred to a receiver, and the upper, depleted aqueous layer (AQ1) was transferred to waste. OP1 was returned to the reactor, which had been charged with water (750 mL) and 25% ammonia (750 mL).The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP2) was transferred to a receiver and the upper aqueous layer (AQ2) was transferred to waste. OP2 was charged with methanol (375 mL) and water (1500 mL). The resulting mixture was returned to the reactor. The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP3) was transferred to a receiver and the upper, aqueous layer (AQ3) was transferred to waste. OP3 was returned to the reactor, which had been charged with methanol (375 mL) and water (1500 mL). The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP4) was transferred to a receiver and the upper, aqueous layer (AQ4) was transferred to waste. The final washed organic phase (OP4) was returned to the reactor and concentrated under vacuum to a volume of 2700 mL.

[0361] Water (150 mL), Boc-(S)-HABA (153 g, 0.698 mol, 1.04 equiv.), and 1-hydroxybenzotriazole (17 g, 0.126 mol, 0.19 equiv.) were added to the reactor. After each solid (Boc-(S)-HABA and 1-hydroxybenzotriazole) was charged, dichloromethane (60 mL) was used to rinse the charging system. The pH of the reaction mixture was adjusted to 4.8 using 2 M hydrochloric acid (1250 mL). After the pH adjustment, 1-ethyl-3-(3'dimethylaminopropyl)carbodiimide hydrochloride (133 g, 0.694 mol, 1.03 equiv.) was charged to the reaction mixture. Dichloromethane (60 mL) was used to rinse the solid charge. After 70 minutes, the reaction was sampled and deemed complete by HPLC (consumption of 4-nitrobenzyl(((2S,3R)-2-(((1R,2R,3S,4R,6S)-4-amino-6-((tert-butoxycarbonyl)amino)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-6-yl)met). Methanol (675 mL) was charged to the reaction mixture, followed by dichloromethane (3600 mL) and water (1500 mL). The pH was adjusted to 10.5 using sodium hydroxide (1264 mL). The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP5) was transferred to a receiver and the upper aqueous layer (AQ5) was transferred to waste. OP5, followed by water (2100 mL), was returned to the reactor. The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP6) was transferred to a receiver and the upper aqueous layer (AQ6) was transferred to waste. OP6 was returned to the reactor and concentrated under vacuum to a final volume of 3000 mL. Acetonitrile (3000 mL) was charged to the reactor and the mixture was concentrated under vacuum to a final volume target of 3000 mL. Acetonitrile (3000 mL) was charged to the reactor and the mixture was concentrated under vacuum to a final volume target of 3000 mL. Acetonitrile (approximately 3000 mL) was charged to the reaction mixture to a final volume target of 6000 mL.

[0362] The mixture was heated to reflux (83° C.) and two portions of water (75 mL and 38 mL) were added sequentially to form a solution. The solution was cooled to 75° C., after which 4-nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, Formula (4a), seeds (3 g, 0.0029 mmol, 0.004 equivalents) were charged to the reaction mixture. The newly formed slurry was cooled to 3 °C over 5 h and mixed at 0-5 °C for an additional 4 h. The mixture was filtered, washed with acetonitrile (two portions of 300 mL), and dried under vacuum to give 4-nitrobenzyl(((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3, 4-Dihydro-2H-pyran-6-yl)methyl)carbamate, formula (4a), (347.03 g, 50% yield) was obtained.

[0363] Example 5d A jacketed glass reactor equipped with an overhead stirrer was charged with sisomicin free base (90.0 g, KF = 5.65), followed by methanol (450 mL) and dichloromethane (450 mL). After dissolution, the reaction temperature was allowed to stabilize at 15°C. A solution of p-nitrobenzyl benzotriazole carbamate (62 g) in dichloromethane (1260 mL) was added to the reactor over 3 hours, maintaining the reaction temperature at approximately 15°C. The addition was completed with a dichloromethane (90 mL) rinse. After 32 minutes, the reaction was sampled and deemed complete by HPLC analysis (sisomicin consumption). The crude reaction mixture was concentrated under vacuum to a final volume of 450 mL.

[0364] Methanol (1350 mL) was charged to the reaction mixture, and the reaction was further concentrated under vacuum to a final volume target of 1350 mL. A second portion of methanol (270 mL) was charged to the reaction mixture, and the temperature was allowed to stabilize at 27.5 °C. Triethylamine (132 mL, 0.952 mol, 4.74 eq) and zinc acetate dihydrate (146 g, 0.665 mol, 3.31 eq) were charged sequentially, and the mixture was mixed for 1 h. A previously prepared solution of di-tert-butyl-dicarbonate (228 g, 1.045 mol, 5.19 eq) in methanol (180 mL) was added to the reaction solution over 70 min. A methanol (18 mL) rinse completed the transfer. After the addition, the reaction was stirred at 27.5° C. for 13 hours, at which time the reaction was sampled and analyzed by HPLC (4-nitrobenzyl(((2S,3R)-3-amino-2-(((1R,2S,3S,4R,6S)-4,6-diamino-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, The reaction was deemed complete upon consumption of the mono-Boc-protected intermediate, 4-nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-4,6-diamino-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate. The crude reaction mixture was concentrated under vacuum to a final volume of 1080 mL. The temperature was allowed to stabilize at 20-30 °C and the reaction was quenched by the addition of 25% ammonia (540 mL) over 37 min (Caution: addition was exothermic; addition rate was controlled to maintain the reaction temperature at 20-30 °C). Dichloromethane (900 mL) was added and the biphasic mixture was mixed for 20 minutes, after which stirring was stopped and the layers were allowed to separate. The lower, product-rich organic layer (OP1) was transferred to a receiver and the upper, depleted aqueous layer (AQ1) was transferred to waste.OP1 was returned to the reactor charged with water (225 mL) and 25% ammonia (225 mL). The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP2) was transferred to a receiver and the upper aqueous layer (AQ2) was transferred to waste. OP2 was returned to the reactor charged with methanol (90 mL) and water (450 mL). The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP3) was transferred to a receiver and the upper aqueous layer (AQ3) was transferred to waste. OP3 was returned to the reactor charged with methanol (90 mL) and water (450 mL). The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP4) was transferred to a receiver and the upper aqueous layer (AQ4) was transferred to waste. The final washed organic phase (OP4) was returned to the reactor and concentrated under vacuum to a volume of 810 mL.

[0365] Water (45 mL), Boc-(S)-HABA (46 g, 0.210 mol, 1.04 equiv.), and 1-hydroxybenzotriazole (5 g, 0.037 mol, 0.18 equiv.) Amount of 1-methyl-3-(3'dimethylaminopropyl)carbodiimide hydrochloride (40 g, 0.209 mol, 1.04 equiv.) was added to the reactor. After charging each solid (Boc-(S)-HABA and 1-hydroxybenzotriazole), dichloromethane (18 mL) was used to rinse the charging system. The pH of the reaction mixture was adjusted to 5.5 using 2 M hydrochloric acid (380 mL). After the pH adjustment, 1-ethyl-3-(3'dimethylaminopropyl)carbodiimide hydrochloride (40 g, 0.209 mol, 1.04 equiv.) was charged to the reaction mixture. Dichloromethane (18 mL) was used to rinse the solid charge. After 2 hours and 40 minutes, the reaction was sampled and deemed complete by HPLC (consumption of 4-nitrobenzyl(((2S,3R)-2-(((1R,2R,3S,4R,6S)-4-amino-6-((tert-butoxycarbonyl)amino)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-6-yl)met). Methanol (180 mL) was charged to the reaction mixture, followed by dichloromethane (1080 mL) and water (450 mL). The pH was adjusted to 9.5 using sodium hydroxide (400 mL). The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP5) was transferred to a receiver and the upper aqueous layer (AQ5) was transferred to waste. OP5, followed by water (630 mL), was returned to the reactor. The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP6) was transferred to a receiver and the upper aqueous layer (AQ6) was transferred to waste. OP6 was returned to the reactor and concentrated under vacuum to a final volume of 3000 mL. Acetonitrile (900 mL) was charged to the reactor and the mixture was concentrated under vacuum to a final volume target of 900 mL. Acetonitrile (900 mL) was charged to the reactor and the mixture was concentrated under vacuum to a final volume target of 900 mL. Acetonitrile (approximately 1350 mL) was charged to the reaction mixture to a final volume target of 2250 mL.

[0366] The mixture was heated to reflux (approximately 80° C.) and two portions of water (23 mL and 11 mL) were added sequentially to form a solution. The solution was cooled to 75° C., after which 4-nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, Formula (4a), seed (1 g, 0.0010 mol, 0.005 equivalents) was charged to the reaction mixture. The newly formed slurry was cooled to 3°C over 5 hours and mixed at 0-5°C for an additional 4 hours. The mixture was filtered, washed with acetonitrile (two portions of 300 mL), and dried under vacuum to give 4-nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, Formula (4a), (105.43 g, molar yield 51%).

[0367] Example 5e A jacketed glass reactor equipped with an overhead stirrer was charged with sisomicin free base (300.0 g, 0.670 mol, 1 equiv, KF = 5.65), followed by methanol (1500 mL) and dichloromethane (1500 mL). After dissolution, the reaction temperature was stabilized at 15 °C. A solution of p-nitrobenzyl benzotriazole carbamate (226 g, 0.758 mol, 1.13 equiv) in dichloromethane (4200 mL) was added to the reaction mixture at 15 °C. The reaction mixture was added to the reactor over 3 hours, maintaining the temperature at approximately 15°C. A dichloromethane (300 mL) rinse completed the addition. After 30 minutes, the reaction was sampled and deemed complete by HPLC analysis (sisomicin consumption). The crude reaction mixture was concentrated under vacuum to a final volume of 1500 mL. Methanol (4500 mL) was charged to the reaction mixture, and a second concentration under vacuum was performed to a volume target of 4500 mL.

[0368] Methanol (900 mL) was charged to the reaction mixture and the temperature was allowed to stabilize at 20 °C. Triethylamine (498 mL, 3.593 mol, 5.36 eq) and zinc acetate dihydrate (425 g, 1.936 mol, 2.89 eq) were charged sequentially, and the mixture was mixed for 1 h. A previously prepared solution of di-tert-butyl-dicarbonate (894 g, 4.096 mol, 6.11 eq) in methanol (600 mL) was added to the reaction solution over 60 min. A methanol (60 mL) rinse completed the transfer. After the addition, the reaction was stirred at 20.0° C. for 9 hours, at which time the reaction was sampled and analyzed by HPLC (4-nitrobenzyl(((2S,3R)-3-amino-2-(((1R,2S,3S,4R,6S)-4,6-diamino-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, and The reaction was deemed complete upon consumption of the mono-Boc protected intermediate 4-nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-4,6-diamino-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate. The crude reaction mixture was concentrated under vacuum to a final volume of 3000 mL. The temperature was stabilized at 20-30 °C and the reaction was quenched by the addition of 25% ammonia (1500 mL) over 109 minutes (Caution: addition was exothermic; addition rate was controlled to maintain the reaction temperature at 20-30 °C). Dichloromethane (3000 mL) was added and the biphasic mixture was mixed for 20 minutes, after which stirring was stopped and the layers were allowed to separate. The lower, product-rich organic layer (OP1) was transferred to a receiver, and the upper, depleted aqueous layer (AQ1) was transferred to waste. OP1 was returned to the reactor, which had been charged with water (750 mL) and 25% ammonia (750 mL).The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP2) was transferred to a receiver and the upper aqueous layer (AQ2) was transferred to waste. OP2 was returned to the reactor, which had been charged with methanol (225 mL) and water (1500 mL). The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP3) was transferred to a receiver and the upper aqueous layer (AQ3) was transferred to waste. OP3 was returned to the reactor, which had been charged with methanol (225 mL) and water (1500 mL). The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP4) was transferred to a receiver and the upper aqueous layer (AQ4) was transferred to waste. The final washed organic phase (OP4) was returned to the reactor and concentrated under vacuum to a volume of 2700 mL.

[0369] Water (150 mL), Boc-(S)-HABA (153 g, 0.698 mol, 1.04 equiv.), and 1-hydroxybenzotriazole (17 g, 0.126 mol, 0.19 equiv.) were added to the reactor. After each solid (Boc-(S)-HABA and 1-hydroxybenzotriazole) was charged, dichloromethane (60 mL) was used to rinse the charging system. The pH of the reaction mixture was adjusted to 6.2 using 2 M hydrochloric acid (1112 mL). After the pH adjustment, 1-ethyl-3-(3'dimethylaminopropyl)carbodiimide hydrochloride (133 g, 0.694 mol, 1.03 equiv.) was charged to the reaction mixture. Dichloromethane (60 mL) was used to rinse the solid charge. After 4 hours, the reaction was sampled and purified by HPLC (4-nitrobenzyl(((2S,3R)-2-(((1R,2R,3S,4R,6S)-4-amino-6-((tert-butoxycarbonyl)amino)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methyl The reaction was deemed complete by consumption of ((tert-butoxycarbonyl)amino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-6-yl)met. Methanol (525 mL) was charged to the reaction mixture, followed by dichloromethane (3600 mL) and water (1500 mL). The pH was adjusted to 8.5 using sodium hydroxide (430 mL). The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP5) was transferred to a receiver and the upper aqueous layer (AQ5) was transferred to waste. OP5, followed by water (2100 mL) was returned to the reactor. The layers were mixed by stirring and then allowed to separate, after which the lower, product-rich organic layer (OP6) was transferred to a receiver and the upper aqueous layer (AQ6) was transferred to waste. OP6 was returned to the reactor and concentrated under vacuum to a final volume of 3000 mL. Acetonitrile (3000 mL) was charged to the reactor and the mixture was concentrated under vacuum to a final volume target of 3000 mL. Acetonitrile (3000 mL) was charged to the reactor and the mixture was concentrated under vacuum to a final volume target of 3000 mL. Acetonitrile (approximately 6000 mL) was charged to the reaction mixture to a final volume target of 9000 mL.

[0370] The mixture was heated to reflux (83° C.) and two portions of water (75 mL and 38 mL) were added sequentially to form a solution. The solution was cooled to 80° C., after which 4-nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, Formula (4a), seed (3 g, 0.0029 mol, 0.004 equivalents) was charged to the reaction mixture. The newly formed slurry was cooled to 3°C over 5 hours and mixed at 0-5°C for an additional 4 hours. The mixture was filtered, washed with acetonitrile (two portions of 300 mL), and dried under vacuum to give 4-nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, Formula (4a), (364.8 g, molar yield 53%). Example 6: 4-Nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, from formula (4a) Example of procedure for the preparation of tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, formula (6a). [ka]

[0371] Example 6a A jacketed glass reactor equipped with an overhead stirrer (Reactor A) was charged with 4-nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, Formula (4a), (320 g, 0.311 mol, 1 equivalent). Methanol (3200 mL) was charged to the reactor and the temperature was stabilized at 45-55°C (47°C). A previously prepared solution of di-tert-butyl-dicarbonate (81.60 g, 0.374 mol, 1.20 equiv.) in methanol (80 mL) was added to the reaction solution over 3 min. A methanol (80 mL) rinse completed the charge. After 3 hours, the reaction was sampled and deemed complete by HPLC analysis (4-nitrobenzyl(((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, Formula (4a) consumption).

[0372] A second jacketed glass reactor (Reactor B) equipped with an overhead stirrer was charged with water (2810 g) and sodium hydroxide (131 g, 3.275 mol, 10.52 equiv.). The basic solution was cooled to 10° C. Sodium dithionite (402 g) was charged to the solution and the temperature was stabilized at 12.5° C.

[0373] The reaction mixture (Reactor A) containing the intermediate tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((((4-nitrobenzyl)oxy)carbonyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate was added to the reaction mixture (Reactor A) containing the intermediate tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-((((4-nitrobenzyl)oxy)carbonyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate with dithionite salt at a temperature of 12.5° C. The mixture was transferred to the sodium dithionite mixture (Reactor B) over 1 hour while maintaining the temperature. Methanol (160 mL) was charged to complete the transfer. Upon completion of the addition, the reaction mixture was heated to 20° C. for 3 hours. After 14 hours, the reaction was sampled and deemed complete by HPLC analysis (consumption of tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-((((4-aminobenzyl)oxy)carbonyl)amino)methyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate). The reaction was concentrated under vacuum to a final volume of 4160 mL at a maximum jacket temperature of 35 °C. Isopropyl acetate (1280 mL) and water (1920 mL) were charged to the reaction mixture. The layers were mixed by stirring at 35 °C and then allowed to separate, after which the lower aqueous layer (AP1) and upper organic layer (OP1) were transferred to a receiver. AP1 was returned to the reactor and extracted with another portion of isopropyl acetate (640 mL) to produce aqueous layer 2 (AP2) and organic layer (OP2). AP2 was sent to waste, and OP2 was combined with OP1 in the reactor. This combined product-rich organic solution was washed with two portions of 6.5% sodium bicarbonate solution (two portions of 960 mL). The washed organic phase was concentrated under vacuum to a volume target of 960 mL. Isopropyl acetate (960 mL) was charged to the reactor, and a second azeotropic distillation was performed to a volume target of 960 mL. Another portion of isopropyl acetate (960 mL) was charged to the reactor and a third azeotropic distillation was performed to a volume target of 1120 mL. The temperature was stabilized at 37.5°C and water (17 mL) was charged to the mixture to achieve a KF of 1.5% w / w. Dichloromethane (1120 mL) was charged to the reactor and the temperature was stabilized at 10.7°C.The mixture was seeded with tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a), (6.4 g, 0.0067 mol, 0.02 equivalents). One portion of dichloromethane (32 mL) was used to rinse out the seeds. The seeded mixture was mixed at 10° C. for 2 hours and cooled to 0° C. over a 2 hour period. The slurry was mixed for an additional 3.5 hours after which it was filtered and washed with dichloromethane (320 mL). The isolated material was dried in a vacuum oven to provide tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a), (259.66 g, 88% molar yield).

[0374] Example 6b A jacketed glass reactor (Reactor A) equipped with an overhead stirrer was charged with 4-nitrobenzyl(((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2 (3,4-Dihydro-2H-pyran-6-yl)methyl)carbamate, Formula (4a), (320 g, 0.311 mol, 1 equiv.) was charged. Methanol (3,200 mL) was charged to the reactor, and the temperature was stabilized at 45-55°C (50°C). A previously prepared solution of di-tert-butyl dicarbonate (81.60 g, 0.374 mol, 1.20 equiv.) in methanol (80 mL) was added to the reaction solution over 5 min. A methanol (80 mL) rinse completed the charge. After 5 h, an additional portion of a previously prepared solution of di-tert-butyl dicarbonate (1.92 g) in methanol (1.9 mL) was added to the reaction solution. After 1 hour, the reaction was sampled and deemed complete by HPLC analysis (4-nitrobenzyl(((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, Formula (4a) consumption).

[0375] A second jacketed glass reactor (Reactor B) equipped with an overhead stirrer was charged with water (2490 g) and sodium hydroxide (125 g, 3.125 mol, 10.04 equiv.). The basic solution was cooled to 5° C. Sodium dithionite (383 g, 2.200 mol, 7.07 equiv.) was charged to the solution and the temperature was stabilized at 7.5° C.

[0376] Intermediate tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((((4-nitrobenzyl)oxy)carbonyl The reaction mixture containing 2,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate (Reactor A) was transferred to the sodium dithionite mixture (Reactor B) over 1 hour while maintaining the temperature of the dithionite reaction mixture at 7.5° C. Methanol (160 mL) was charged to complete the transfer. Upon completion of the addition, the reaction mixture was heated to 27.5° C. over 2 hours. After 7 hours, the reaction was sampled and deemed complete by HPLC analysis (consumption of tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-((((4-aminobenzyl)oxy)carbonyl)amino)methyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate). The reaction was concentrated under vacuum to a final volume of 4160 mL at a maximum jacket temperature of 35°C. Isopropyl acetate (1280 mL) and water (1920 mL) were charged to the reaction mixture. The layers were mixed by stirring at 35°C and then allowed to separate, after which the lower aqueous layer (AP1) and upper organic layer (OP1) were transferred to a receiver. AP1 was returned to the reactor and extracted with another portion of isopropyl acetate (640 mL) to produce aqueous layer 2 (AP2) and organic layer (OP2). AP2 was sent to waste, and OP2 was combined with OP1 in the reactor.The combined product-rich organic solution was washed with two portions of 6.5% sodium bicarbonate solution (two portions of 960 mL). The washed organic phase was concentrated under vacuum to a volume target of 960 mL. Isopropyl acetate (960 mL) was charged to the reactor and a second azeotropic distillation was performed to a volume target of 960 mL. Another portion. Isopropyl acetate (960 mL) was charged to the reactor and a third azeotropic distillation was performed to a volume target of 1440 mL. The temperature was stabilized at 37.5°C and water (42 mL) was charged to the mixture to achieve a KF of 2.9% w / w. Dichloromethane (1440 mL) was charged to the reactor and the temperature was stabilized at 22.5°C. The mixture was seeded with tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a), (6.4 g, 0.0067 mol, 0.02 equivalents). One portion of dichloromethane (32 mL) was used to rinse out the seeds. The seeded mixture was mixed at 22.5° C. for 2 hours and cooled to 0° C. over a 2 hour period. The slurry was mixed for an additional 3.5 hours after which it was filtered and washed with dichloromethane (320 mL). The isolated material was dried in a vacuum oven to provide tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a), (257.77 g, 87% yield).

[0377] Example 6c A jacketed glass reactor equipped with an overhead stirrer (Reactor A) was charged with 4-nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, Formula (4a), (320 g, 0.311 mol, 1 equivalent). Methanol (3200 mL) was charged to the reactor and the temperature was stabilized at 45-55 °C (50 °C). A previously prepared solution of di-tert-butyl-dicarbonate (81.60 g, 0.394 mol, 1.20 equiv.) in methanol (80 mL) was added to the reaction solution over 3 min. A methanol (80 mL) rinse completed the charge. After 3 hours, the reaction was sampled and deemed complete by HPLC analysis (4-nitrobenzyl(((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, Formula (4a) consumption).

[0378] A second jacketed glass reactor (Reactor B) equipped with an overhead stirrer was charged with water (2170 g) and sodium hydroxide (118 g, 2.950 mol, 9.48 equiv.). The basic solution was cooled to 0° C. Sodium dithionite (364 g, 2.091 mol, 6.72 equiv.) was charged to the solution and the temperature was stabilized at 2.5° C.

[0379] Intermediate tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((((4-nitrobenzyl)oxy)carbonyl The reaction mixture containing 2,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate (Reactor A) was transferred to the sodium dithionite mixture (Reactor B) over 5 hours while maintaining the temperature of the dithionite reaction mixture at 2.5° C. Methanol (160 mL) was charged to complete the transfer. Upon completion of the addition, the reaction mixture was heated to 35° C. for 1 hour. After 3 hours, the reaction was sampled and deemed complete by HPLC analysis (consumption of tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-((((4-aminobenzyl)oxy)carbonyl)amino)methyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate). The reaction was concentrated under vacuum to a final volume of 4160 mL at a maximum jacket temperature of 35°C. Isopropyl acetate (1280 mL) and water (1920 mL) were charged to the reaction mixture. The layers were mixed by stirring at 35°C and then allowed to separate, after which the lower aqueous layer (AP1) and upper organic layer (OP1) were transferred to a receiver. AP1 was returned to the reactor and extracted with another portion of isopropyl acetate (640 mL) to produce aqueous layer 2 (AP2) and organic layer (OP2). AP2 was sent to waste, and OP2 was combined with OP1 in the reactor.The combined product-rich organic solution was washed with two portions of 6.5% sodium bicarbonate solution (two portions of 960 mL). The washed organic phase was concentrated under vacuum to a volume target of 960 mL. Isopropyl acetate (960 mL) was charged to the reactor and a second azeotropic distillation was performed to a volume target of 960 mL. Another portion of isopropyl acetate (960 mL) was charged to the reactor and a third azeotropic distillation was performed to a volume target of 1760 mL. The temperature was stabilized at 37.5°C and water (71.2 mL) was charged to the mixture to achieve a KF of 3.9% w / w. Dichloromethane (1760 mL) was charged to the reactor and the temperature was stabilized at 35°C. The mixture was seeded with tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a), (6.4 g, 0.0067 mol, 0.02 equivalents). One portion of dichloromethane (32 mL) was used to rinse out the seeds. The seeded mixture was mixed at 35° C. for 2 hours and cooled to 0° C. over a 2 hour period. The slurry was mixed for an additional 3.5 hours after which it was filtered and washed with dichloromethane (320 mL). The isolated material was dried in a vacuum oven to provide tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a), (103.5 g, 0.109 mol, 35% molar yield).

[0380] Example 6d A jacketed glass reactor equipped with an overhead stirrer (Reactor A) was charged with 4-nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, Formula (4a), (320 g, 0.311 mol, 1 equivalent). Methanol (3200 mL) was charged to the reactor and the temperature was stabilized at 45-55°C (47°C). A previously prepared solution of di-tert-butyl-dicarbonate (81.60 g, 0.374 mol, 1.20 equiv.) in methanol (80 mL) was added to the reaction solution over 3 min. A methanol (80 mL) rinse completed the charge. After 6 hours, the reaction was sampled and deemed complete by HPLC analysis (4-nitrobenzyl(((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, Formula (4a) consumption).

[0381] A second jacketed glass reactor (Reactor B) equipped with an overhead stirrer was charged with water (2810 g) and sodium hydroxide (131.2 g, 3.280 mol, 10.54 equiv.). The basic solution was cooled to 10° C. Sodium dithionite (401.9 g, 2.308 mol, 7.42 equiv.) was charged to the solution and the temperature was stabilized at 12.5° C.

[0382] Intermediate tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((((4-nitrobenzyl)oxy)carbonyl The reaction mixture containing 2,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate (Reactor A) was transferred to the sodium dithionite mixture (Reactor B) over 1 hour while maintaining the temperature of the dithionite reaction mixture at 12.5° C. Methanol (160 mL) was charged to complete the transfer. Upon completion of the addition, the reaction mixture was heated to 20° C. for 3 hours. After 18 hours, the reaction was sampled and deemed complete by HPLC analysis (consumption of tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-((((4-aminobenzyl)oxy)carbonyl)amino)methyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate). The reaction was concentrated under vacuum to a final volume of 4160 mL at a maximum jacket temperature of 35° C. Isopropyl acetate (1280 mL) and water (1920 mL) were charged to the reaction mixture. The layers were mixed by stirring at 35° C., and then The mixture was allowed to separate, after which the lower aqueous layer (AP1) and upper organic layer (OP1) were transferred to a receiver. AP1 was returned to the reactor and further extracted with another portion of isopropyl acetate (640 mL) to produce aqueous layer 2 (AP2) and organic layer (OP2). AP2 was sent to waste, and OP2 was combined with OP1 in the reactor. This combined product-rich organic solution was washed with two portions of 6.5% sodium bicarbonate solution (two portions of 960 mL). The washed organic phase was concentrated under vacuum to a volume target of 960 mL. Isopropyl acetate (960 mL) was charged to the reactor, and a second azeotropic distillation was performed to a volume target of 960 mL. Another portion of isopropyl acetate (960 mL) was charged to the reactor, and a third azeotropic distillation was performed to a volume target of 1280 mL. The temperature was stabilized at 37.5°C and water (26 mL) was charged to the mixture to achieve a KF of 2.1% w / w. Dichloromethane (1280 mL) was charged to the reactor and the temperature was stabilized at 15.1°C. The mixture was seeded with tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a), (6.4 g, 0.0067 mol, 0.02 equivalents). One portion of dichloromethane (32 mL) was used to rinse out the seeds. The seeded mixture was mixed at 15° C. for 2 hours and cooled to 0° C. over a 2 hour period. The slurry was mixed for an additional 3.5 hours after which it was filtered and washed with dichloromethane (320 mL).The isolated material was dried in a vacuum oven to provide tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a), (257.5 g, 0.271 mol, 87% molar yield).

[0383] Example 6e A jacketed glass reactor equipped with an overhead stirrer (Reactor A) was charged with 4-nitrobenzyl (((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, Formula (4a), (320 g, 0.311 mol, equivalents). Methanol (3200 mL) was charged to the reactor and the temperature was stabilized at 45-55°C (47°C). A previously prepared solution of di-tert-butyl-dicarbonate (81.60 g, 0.374 mol, 1.20 equiv.) in methanol (80 mL) was added to the reaction solution over 3 min. A methanol (80 mL) rinse completed the charge. After 8 hours, the reaction mixture was sampled and analyzed by HPLC (4-nitrobenzyl(((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-(((1R,2S,3S,4R,6S)-6-((tert-butoxycarbonyl)amino)-4-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2R,3R,4R,5R)-3,5-dihydroxy-5-methyl-4-(methylamino)tetrahydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,4-dihydro-2H-pyran-6-yl)methyl)carbamate, formula (4a) consumed). was considered completed by

[0384] A second jacketed glass reactor (Reactor B) equipped with an overhead stirrer was charged with water (2170 g) and sodium hydroxide (118.4 g, 2.960 mol, 9.51 equiv.). The basic solution was cooled to 0° C. Sodium dithionite (363.5 g, 2.088 mol, 6.71 equiv.) was charged to the solution and the temperature was stabilized at 2.5° C.

[0385] Intermediate tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((((4-nitrobenzyl)oxy)carbonyl The reaction mixture containing 2,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate (Reactor A) was transferred to the sodium dithionite mixture (Reactor B) over 5 hours while maintaining the temperature of the dithionite reaction mixture at 2.5° C. Methanol (160 mL) was charged to complete the transfer. Upon completion of the addition, the reaction mixture was heated to 35° C. for 1 hour. After 4 hours, the reaction was sampled and deemed complete by HPLC analysis (consumption of tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-((((4-aminobenzyl)oxy)carbonyl)amino)methyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate). The reaction was concentrated under vacuum to a final volume of 4160 mL at a maximum jacket temperature of 35°C. Isopropyl acetate (1280 mL) and water (1920 mL) were charged to the reaction mixture. The layers were mixed by stirring at 35°C and then allowed to separate, after which the lower aqueous layer (AP1) and upper organic layer (OP1) were transferred to a receiver. AP1 was returned to the reactor and extracted with another portion of isopropyl acetate (640 mL) to produce aqueous layer 2 (AP2) and organic layer (OP2). AP2 was sent to waste, and OP2 was combined with OP1 in the reactor.The combined product-rich organic solution was washed with two portions of 6.5% sodium bicarbonate solution (two portions of 960 mL). The washed organic phase was concentrated under vacuum to a volume target of 960 mL. Isopropyl acetate (960 mL) was charged to the reactor, and a second azeotropic distillation was performed to a volume target of 960 mL. Another portion of isopropyl acetate (960 mL) was charged to the reactor, and a third azeotropic distillation was performed to a volume target of 1600 mL. The temperature was stabilized at 37.5 °C, and water (29 mL) was charged to the mixture to achieve a KF of 3.5% w / w. Dichloromethane (1600 mL) was charged to the reactor, and the temperature was stabilized at 30 °C. The mixture was seeded with tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a), (6.4 g, 0.0067 mol, 0.02 equivalents). One portion of dichloromethane (32 mL) was used to rinse off the seeds. The seeded mixture was mixed at 30° C. for 2 hours and cooled to 0° C. over a 2 hour period. The slurry was mixed for an additional 3.5 hours after which it was filtered and washed with dichloromethane (320 mL). The isolated material was dried in a vacuum oven. to give tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, formula (6a), (259.50 g, 0.273 mol, 88% molar yield). Example 7: tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, tert-butyl from formula (6a) Example of a procedure for preparing aryl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, formula (7a). [ka]

[0386] Example 7a A jacketed glass reactor equipped with an overhead stirrer was charged with tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a), (250 g, 0.263 mol, 1 equivalent). Acetonitrile (1250 mL) was charged to the reactor and the temperature was allowed to stabilize at 15-30°C (27.4°C). The mixture was concentrated under vacuum to a final volume target of 500 mL. The solution was sampled for water content by KF, which gave a result of 0.27% w / w. An additional portion of acetonitrile (750 mL) was charged to the reactor and a second azeotropic distillation was performed to a volume target of 500 mL. The mixture was sampled by KF, which gave a result of 0.08% w / w. The reaction temperature was allowed to stabilize at 29.9°C, and acetone (1250 mL) was charged to the mixture. The reaction was heated and the temperature was allowed to stabilize at 40°C. Sodium bicarbonate (44.25 g, 0.527 mol, 2 equiv.) was charged to the reaction mixture, followed by 2-iodoethanol (65.2 g, 29.6 mL, 0.379 mol, 1.44 equiv.). After 23 hours, the reaction was sampled and analyzed by HPLC (tert-butyl ((2R,3R,4R,5R)-2-(((1S,2 The reaction was deemed complete upon consumption of (S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a). The reaction was cooled to 22.7° C. and 1,4-diazabicyclo[2.2.2]octane (60.0 g, 0.535 mol, 2.03 equiv.) was charged as a solid. The destruction of 2-iodoethanol was monitored by GC, and quenching of this reagent was deemed complete after 18 hours. Water (1250 mL) and isopropyl acetate (1250 mL) were charged to the reaction mixture. The reactor contents were stirred for 25 minutes, and the layers were allowed to separate. The lower aqueous layer (AP1) and the upper organic layer (OP1) were collected in a receiver. AP1 was returned to the reactor, and a second portion of isopropyl acetate (750 mL) was charged. The reactor contents were stirred for 30 minutes, and the layers were allowed to separate. The lower aqueous layer (AP2) and the upper organic layer (OP2) were collected in a receiver. OP1 and OP2 were combined in the reactor and extracted with two portions of saturated sodium chloride solution (750 mL, prepared by dissolving 100 g of NaCl in 290 mL of water). The washed organic phase (OP4) was concentrated under vacuum to a volume target of 500 mL. Acetonitrile (2550 mL) was charged to the reactor. A second azeotropic vacuum distillation was performed to a volume target of 2050 mL. Isopropyl acetate (200 mL) was charged to the mixture. Water (35.4 mL) was charged to the mixture until a KF of 2.0% was obtained. The reactor contents were heated to 75° C., whereupon a solution was obtained.The reaction mixture was cooled to 65° C. and seeded with tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (7a), (5 g, 0.0050 mol, 0.02 equiv.). Stirring was maintained at 65°C for 8 hours, during which time a thick slurry formed. The mixture was cooled from 65°C to 2.5°C over 12 hours. The slurry was filtered, washed with acetonitrile (900 mL), and dried in a vacuum oven to give tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (7a), (203.8 g, 0.205 mol, 78% yield).

[0387] Example 7b A jacketed glass reactor equipped with an overhead stirrer was charged with tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a), (250 g, 0.263 mol, 1 equivalent). Acetonitrile (1250 mL) was charged to the reactor and the temperature was stabilized at 15-30°C (30°C). The mixture was concentrated under vacuum to a final volume target of 500 mL. The solution was sampled for water content by KF, which gave a result of 0.18% w / w. An additional portion of acetonitrile (750 mL) was charged to the reactor, and a second azeotropic distillation was performed to a volume target of 500 mL. The mixture was sampled by KF, which gave a result of 0.075% w / w. The reaction temperature was stabilized at 29.9 °C, and acetone (1250 mL) was charged to the mixture. The reaction was heated, and the temperature was stabilized at 40 °C. Sodium bicarbonate (44.25 g, 0.527 mol, 2.0 eq) was charged to the reaction mixture, followed by 2-iodoethanol (56.6 g, 25.7 mL, 0.329 mol, 1.25 eq). After 56 hours, the reaction was sampled and deemed complete by HPLC analysis (tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a) consumption). The reaction was cooled to 22.7 °C and 1,4-diazabicyclo[2.2.2]octane (60.0 g, 0.535 mol, 2.0 equiv.) was charged as a solid. The destruction of 2-iodoethanol was monitored by GC, and quenching of this reagent was deemed complete after 18 h. Water (1250 mL) and isopropyl acetate (1250 mL) were charged to the reaction mixture. The reactor contents were stirred for 25 minutes and the layers were allowed to separate. The lower aqueous layer (AP1) and upper organic layer (OP1) were collected in a receiver. AP1 was returned to the reactor, and a second portion of isopropyl acetate (750 mL) was charged. The reactor contents were stirred for 30 minutes and the layers were allowed to separate. The lower aqueous layer (AP2) and upper organic layer (OP2) were collected in a receiver.OP1 and OP2 were combined in a reactor and extracted with two portions of saturated sodium chloride solution (750 mL, prepared by dissolving 100 g of NaCl in 290 mL of water). The washed organic phase (OP4) was concentrated under vacuum to a volume target of 500 mL. Acetonitrile (2550 mL) was charged to the reactor. A second azeotropic vacuum distillation was performed to a volume target of 1800 mL. Isopropyl acetate (200 mL) was charged to the mixture. Water (22.8 mL) was charged to the mixture until a KF of 1.46% was obtained. The reactor contents were heated to 75°C to obtain a solution. The reaction mixture was cooled to 62.5° C. and seeded with tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (7a), (5 g, 0.0050 mol, 0.02 equivalents). Stirring was maintained at 62.5°C for 5 hours, during which time a thick slurry formed. The mixture was cooled from 65°C to 2.5°C over 12 hours. The slurry was filtered, washed with acetonitrile (900 mL), and dried in a vacuum oven to provide tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (7a), (208.1 g, 0.220 mol, 83% molar yield).

[0388] Example 7c A jacketed glass reactor equipped with an overhead stirrer was charged with tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a), (250 g, 0.263 mol, 1 equivalent). Acetonitrile (1250 mL) was charged to the reactor and the temperature was allowed to stabilize at 15-30°C (24.3°C). The mixture was concentrated under vacuum to a final volume target of 500 mL. The solution was sampled for water content by KF, which gave a result of 0.22% w / w. An additional portion of acetonitrile (750 mL) was charged to the reactor and a second azeotropic distillation was performed to a volume target of 500 mL. The mixture was sampled by KF, which gave a result of 0.097% w / w. The reaction temperature was allowed to stabilize at 29.9°C, and acetone (1250 mL) was charged to the mixture. The reaction was heated and the temperature was allowed to stabilize at 29.9°C. Sodium bicarbonate (44.25 g, 0.527, 2.0 equiv.) was charged to the reaction mixture, followed by 2-iodoethanol (44.4 g, 20.14 mL, 0.258 mol, 0.98 equiv.). After 43 hours, an additional portion of 2-iodoethanol (0.25 mL) was added to the reaction mixture. After 9.5 hours, a third portion of 2-iodoethanol (0.3 mL) was added to the reaction mixture.After an additional 2 hours, the reaction was sampled and deemed complete by HPLC analysis (tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-3-(((2S,3R)-6-(aminomethyl)-3-((tert-butoxycarbonyl)amino)-3,4-dihydro-2H-pyran-2-yl)oxy)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (6a) consumed). The reaction was cooled to 22.7 °C and 1,4-diazabicyclo[2.2.2]octane (60.0 g, 0.535 mol, 2.03 equiv.) was charged as a solid. The destruction of 2-iodoethanol was monitored by GC, and quenching of this reagent was deemed complete after 10 h. Water (1250 mL) and isopropyl acetate (1250 mL) were charged to the reaction mixture. The reactor contents were stirred for 25 min and the layers were allowed to separate. The lower aqueous layer (AP1) and upper organic layer (OP1) were collected in a receiver. AP1 was returned to the reactor, and a second portion of isopropyl acetate (750 mL) was charged. The reactor contents were stirred for 30 min and the layers were allowed to separate. The lower aqueous layer (AP2) and upper organic layer (OP2) were collected in a receiver. OP1 and OP2 were combined in a reactor and extracted with two portions of saturated sodium chloride solution (750 mL, prepared by dissolving 100 g of NaCl in 290 mL of water). The washed organic phase (OP4) was concentrated under vacuum to a volume target of 500 mL. Acetonitrile (2550 mL) was charged to the reactor. A second azeotropic vacuum distillation was performed to a volume target of 1550 mL. Isopropyl acetate (200 mL) was charged to the mixture. Water (10.7 mL) was charged to the mixture until a KF of 0.85% was obtained. The reactor contents were heated to 75°C to obtain a solution.The reaction mixture was cooled to 57° C. and seeded with tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (7a), (5 g, 0.0050 mol, 0.02 equiv.). Stirring was maintained at 57°C for 2 hours, during which time a thick slurry formed. The mixture was cooled from 65°C to 2.5°C over 12 hours. The residue was filtered, washed with acetonitrile (900 mL), and dried in a vacuum oven to give tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (7a), (218.1 g, 0.220 mol, 83% molar yield). Example 8: Example of a procedure for the preparation of plazomicin from Tert-butyl ((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, formula (7a) and regeneration of a CG-50 resin bed. [ka]

[0389] Example 8a A jacketed glass reactor (Reactor A) equipped with an overhead stirrer was charged with tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-(((2S,3R)-3-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido) A mixture of (((2-hydroxyethyl)amino)-6-(((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (7a), (150 g, 0.151 mol, 1 equivalent) and dichloromethane (750 mL) was charged. The mixture was stirred at 0-5°C (0.6°C). Trifluoroacetic acid was added slowly to the reaction mixture while maintaining the temperature at 0-5°C (caution: exothermic addition). Upon completion of the addition, the reaction solution was heated to 22.5°C and held at that temperature for 2 hours. The reaction mixture was concentrated by distillation under vacuum to a final volume target of 450 mL. The concentrated reaction mixture was held at 22.5°C for an additional 2 hours, after which the temperature was allowed to stabilize at 0-10°C (3.0°C).

[0390] A second jacketed glass reactor (Reactor B) equipped with an overhead stirrer was charged with water (375 mL) and cooled to a temperature of 0°C to 5°C (2.5°C). The contents of Reactor A were transferred to the contents of Reactor B over 45 minutes while maintaining a temperature of 0°C to 10°C (beware of exothermic nature of addition). Isopropyl acetate was charged to the reaction mixture, producing a two-phase mixture. The reactor contents were mixed with the overhead stirrer, then stirring was stopped and the layers were allowed to separate. A lower, product-rich aqueous layer (AP1) and an upper, organic layer (OP1) were separated. OP1 was returned to the reactor, and water (75 mL) was charged to the mixture. The reactor contents were then transferred to the overhead stirrer. The contents of the reactor were mixed with an overhead stirrer, then the stirring was stopped and the layers were allowed to separate. The lower product-rich aqueous layer (AP2) and the upper organic layer (OP2) were collected. OP2 was returned to the reactor and charged with water (75 mL). The reactor contents were mixed with an overhead stirrer, then the stirring was stopped and the layers were allowed to separate. The lower product-rich aqueous layer (AP3) and the upper organic layer (OP3) were collected. The three product-rich aqueous layers (AP1, AP2, and AP3) were returned to the reactor and combined. The pH of the combined organic layer was measured as 0.15. Isopropyl acetate (450) was charged to the combined aqueous phase. The reactor contents were mixed with an overhead stirrer, then the stirring was stopped and the layers were allowed to separate. The lower product-rich aqueous layer (AP4) and the upper organic layer (OP4) were collected. The pH of the combined AP4 was measured as 0.73. AP4 was returned to the reactor. Isopropyl acetate (450) was charged to the reactor. The reactor contents were mixed using an overhead stirrer, then the stirring was stopped and the layers were allowed to separate. The lower product-rich aqueous layer (AP5) and the upper organic layer (OP5) were collected. The pH of AP5 was measured at 1.78. AP5 was returned to the reactor. Isopropyl acetate (450) was charged to the reactor. The reactor contents were mixed using an overhead stirrer, then the stirring was stopped and the layers were allowed to separate. The lower product-rich aqueous layer (AP6) and the upper organic layer (OP6) were collected. The pH of AP6 was measured at 2.95. AP6 was returned to the reactor, and the pH was adjusted to 5.8-6.2 (final pH 6.01) using 1% ammonia solution (34.7 mL). The temperature was maintained between 0 and 10 °C during the pH adjustment. Water (approximately 820 mL) was charged to the reaction mixture to a final volume of 1350 mL. The pH was measured again (5.67) and adjusted to 5.8-6.2 (6.01) using 1% ammonia solution (11.7 mL). The conductivity of the solution was measured as 15.36 mS / cm.

[0391] This solution of crude plazomycin was loaded onto an XK-50 / 100 column packed with ammonium-form CG-50 resin (325.5 g) with a headspace filled with water. The column temperature was stabilized at 13 °C. The crude solution was loaded in a downflow mode at a linear flow rate of 10-20 cm / h (approximately 9.2 mL / min). After the crude solution was loaded onto the resin bed, water (1 column volume, 1620 mL) was loaded in a downflow mode at a linear flow rate of 10-20 cm / h (9.2 mL / min). At the end of the water loading, 0.43% ammonia solution (prepared from 86.7 g of 25% ammonia in 5 L of water) was loaded onto the column in a downflow mode until plazomycin eluted from the column, as judged by the UV absorbance trace at 210 nm. After elution of plazomycin was deemed complete, the column was further washed with 5% ammonia solution in a downflow mode. The product-rich fractions (#36–#58) were combined to yield 6520 mL of purified plazomicin free base solution. The ammonia content of the solution was measured by ion chromatography at 2720 μg / mL, and the plazomicin free base concentration was measured by UPLC at 1.17% w / v. This solution was treated by reverse osmosis using an XLE membrane in a dialysis mode until the ammonia (μg / mL) relative to plazomicin (% w / v) was less than 20. Six diavolumes of water were treated to achieve this criterion. The temperature was maintained below 10°C during the ammonia removal process by dialysis. After the ammonia removal process, the pH of the purified plazomicin solution was adjusted to 6.0 using a 6 M sulfuric acid solution (57.5). The temperature during the pH adjustment was maintained between 0–5°C. The neutralized solution was passed through a pre-washed Zetacarbon® 55 charcoal cartridge at a flow rate of 72 L / h.m2 (18 mL / min). After filtration, the cartridge was washed with water (1068 mL) and the wash was combined with the filtered plazomicin solution. The combined filtrate and wash were concentrated to 540 mL using reverse osmosis with an XLE membrane in nanofiltration mode. The concentrated solution was passed through a 0.22 micron filter and isolated by spray drying using a Buchi laboratory spray dryer (89.05 g, 0.106 mol, 70% molar yield).

[0392] Example 8b - Resin Regeneration The XK-50 / 100 column containing CG-50 resin (326 g) was resuspended by the following procedure. A 4% sodium hydroxide solution (0.49 kg NaOH in 11.8 L water) was charged in upflow mode until a conductivity of 110 mS / cm was achieved in the effluent. Water was then charged in upflow mode until a conductivity of 1.5 mS / cm was achieved in the effluent. A 2% sulfuric acid solution (prepared from 0.10 kg concentrated sulfuric acid in 4.9 L water) was charged in upflow mode until a conductivity of 1 mS / cm was achieved in the effluent. Water (4782 mL) was charged in upflow mode until a final conductivity of 4.8 mS / cm was achieved. A 2% ammonia solution (prepared from 400 g 25% ammonia in 9.6 L water) was charged in upflow mode. The final conductivity of the effluent was 970 μS / cm (pH 12.04). The resin was allowed to settle for 1 hour without flow. Water (3419 mL) was charged in downflow mode (13.1 mL / min).

[0393] The resin bed packing was tested by applying an ammonium trifluoroacetate pulse. An ammonium trifluoroacetate solution was prepared by dissolving ammonium trifluoroacetate (1.397 g) in water (106 mL). This 0.1 M ammonium trifluoroacetate solution (27.5 mL) was loaded in a liquid piston mode just above the surface of the CG-50 resin bed. Water was loaded in a downflow mode until the UV absorbance of the ammonium trifluoroacetate pulse could be observed at 210 nm. The resin bed was packed and deemed suitable for use in the purification of crude plazomicin.

[0394] Example 8c A jacketed glass reactor equipped with an overhead stirrer (Reactor A) was charged with tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-((((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-((((2-hydroxyethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyl Tetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (7a), (150 g, 0.151 mol, 1 eq) and dichloromethane (750 mL) were charged. The mixture was stirred at 0-5°C (0.0°C). Trifluoroacetic acid was added slowly to the reaction mixture while maintaining the temperature at 0-5°C (beware of exothermic reaction upon addition). At the end of the addition, the reaction solution was heated to 22.5°C and held at that temperature for 1.5 hours. The reaction mixture was concentrated by distillation under vacuum to a final volume target of 450 mL. The concentrated reaction mixture was held at 22.5°C for an additional 8 hours, after which the temperature was allowed to stabilize at 0-10°C (5.0°C).

[0395] A second jacketed glass reactor (Reactor B) equipped with an overhead stirrer was charged with water (375 mL) and cooled to a temperature of 0°C to 5°C (0.3°C). The contents of Reactor A were transferred to the contents of Reactor B over 19 minutes while maintaining a temperature of 0°C to 10°C (Caution: Exothermic addition). Isopropyl acetate was charged to the reaction mixture, producing a two-phase mixture. The reactor contents were mixed with the overhead stirrer, then stirring was stopped and the layers were allowed to separate. A lower, product-rich aqueous layer (AP1) and an upper, organic layer (OP1) were separated. OP1 was returned to the reactor, and water (75 mL) was charged to the mixture. The reactor contents were mixed with the overhead stirrer, then stirring was stopped and the layers were allowed to separate. A lower, product-rich aqueous layer (AP2) and an upper, organic layer (OP2) were collected. OP2 was returned to the reactor and charged with water (75 mL). The reactor contents were mixed with an overhead stirrer, then the stirring was stopped and the layers were allowed to separate. The lower product-rich aqueous layer (AP3) and the upper organic layer (OP3) were collected. The three product-rich aqueous layers (AP1, AP2, and AP3) were returned to the reactor and combined. The pH of the combined organic layer was measured as 0.49. Isopropyl acetate (450) was charged to the combined aqueous phase. The reactor contents were mixed with an overhead stirrer, then the stirring was stopped and the layers were allowed to separate. The lower product-rich aqueous layer (AP4) and the upper organic layer (OP5) were collected. The lower product-rich aqueous layer (AP5) and the upper organic layer (OP4) were collected. The pH of the combined AP4 was measured at 0.85. AP4 was returned to the reactor. Isopropyl acetate (450) was charged to the reactor. The reactor contents were mixed using an overhead stirrer, then the stirring was stopped and the layers were allowed to separate. The lower product-rich aqueous layer (AP6) and the upper organic layer (OP6) were collected. The pH of AP6 was measured at 2.86. AP6 was returned to the reactor, and the pH was adjusted to 5.8-6.2 (final pH 5.99) using 1% ammonia solution (21 mL). The temperature was maintained between 0 and 10°C during the pH adjustment. Water (approximately 820 mL) was charged to the reaction mixture to a final volume of 1350 mL. The pH was again measured (5.54) and adjusted to 5.8-6.2 (6.01) using 1% ammonia solution (10 mL). The conductivity of the solution was measured as 14.92 mS / cm.

[0396] This solution of crude plazomycin was loaded onto an XK-50 / 100 column packed with 325.5 g of CG-50 resin in the ammonium form with a water-filled headspace. The column temperature was stabilized at 20 °C. The crude solution was loaded in a downflow mode at a linear flow rate of 10-20 cm / h (approximately 9.2 mL / min). After the crude solution was loaded onto the resin bed, water (1 column volume, 1620 mL) was loaded in a downflow mode at a linear flow rate of 10-20 cm / h (9.2 mL / min). At the end of the water loading, 0.50% ammonia solution (prepared from 102 g of 25% ammonia in 5 L of water) was loaded onto the column in a downflow mode until plazomycin eluted from the column, as judged by the UV absorbance trace at 210 nm. The ammonia solution was loaded at a linear flow rate of 38 cm / h (12.4 mL / min). The product-rich fractions (#34–#50) were combined to yield 4800 mL of purified plazomicin free base solution. The ammonia content of the solution was measured by ion chromatography at 3200 μg / mL, and the plazomicin free base concentration was measured by UPLC at 1.52% w / v. This solution was treated by reverse osmosis using an XLE membrane in a dialysis mode until the ammonia (μg / mL) relative to plazomicin (% w / v) was less than 20. Nine diavolumes of water were treated to achieve this criterion. The temperature was maintained below 10°C during the ammonia removal process via the dialysis process. After the ammonia removal process, the pH of the purified plazomicin solution was adjusted to 6.47 using 6 M sulfuric acid solution (52.5). The temperature during the pH adjustment was maintained between 0–5°C. The neutralized solution was passed through a pre-washed Zetacarbon R55 charcoal cartridge at a flow rate of 72 L / h.m² (15 mL / min). After filtration, the cartridge was washed with water (1068 mL) and the wash was combined with the filtered plazomicin solution. The combined filtrate and wash were concentrated to 540 mL using reverse osmosis with an XLE membrane in nanofiltration mode. The concentrated solution was passed through a 0.22 micron filter and isolated by spray drying using a Buchi laboratory spray dryer (88.42 g, 0.106 mol, 70% molar yield).

[0397] Example 8d A jacketed glass reactor (Reactor A) equipped with an overhead stirrer was charged with tert-butyl((2R,3R,4R,5R)-2-(((1S,2S,3R,4S,6R)-4-((tert-butoxycarbonyl)amino)-6-((S)-4-((tert-butoxycarbonyl)amino)-2-hydroxybutanamido)-3-((((2S,3R)-3-((tert-butoxycarbonyl)amino)-6-((((2-hydroxy Ethyl)amino)methyl)-3,4-dihydro-2H-pyran-2-yl)oxy)-2-hydroxycyclohexyl)oxy)-3,5-dihydroxy-5-methyltetrahydro-2H-pyran-4-yl)(methyl)carbamate, Formula (7a), (150 g, 0.151 mol, 1 equivalent) and dichloromethane (750 mL) were charged. The mixture was stirred at 0-5°C (0.9°C). Trifluoroacetic acid was added to the reaction mixture while maintaining the temperature at 0-5°C. The reaction mixture was slowly added (beware of exothermic addition) to the HCl solution. Upon completion of the addition, the reaction solution was heated to 22.5°C and held at that temperature for 1.5 hours. The reaction mixture was concentrated by distillation under vacuum to a final volume target of 450 mL. The concentrated reaction mixture was held at 22.5°C for an additional 6 hours, after which the temperature was allowed to stabilize at 0-10°C (6.5°C).

[0398] A second jacketed glass reactor (Reactor B) equipped with an overhead stirrer was charged with water (375 mL) and cooled to a temperature of 0°C to 5°C (3.5°C). The contents of Reactor A were transferred to the contents of Reactor B over 7 minutes while maintaining a temperature of 0°C to 10°C (Caution: Exothermic addition). Isopropyl acetate was charged to the reaction mixture, producing a two-phase mixture. The reactor contents were mixed with the overhead stirrer, then stirring was stopped and the layers were allowed to separate. A lower, product-rich aqueous layer (AP1) and an upper, organic layer (OP1) were separated. OP1 was returned to the reactor, and water (75 mL) was charged to the mixture. The reactor contents were mixed with the overhead stirrer, then stirring was stopped and the layers were allowed to separate. A lower, product-rich aqueous layer (AP2) and an upper, organic layer (OP2) were collected. OP2 was returned to the reactor and charged with water (75 mL). The reactor contents were mixed with an overhead stirrer, then the stirring was stopped and the layers were allowed to separate. The lower product-rich aqueous layer (AP3) and the upper organic layer (OP3) were collected. The three product-rich aqueous layers (AP1, AP2, and AP3) were returned to the reactor and combined. The pH of the combined organic layer was measured as 0.47. Isopropyl acetate (450) was charged to the combined aqueous phase. The reactor contents were mixed with an overhead stirrer, then the stirring was stopped and the layers were allowed to separate. The lower product-rich aqueous layer (AP4) and the upper organic layer (OP4) were collected. The pH of the combined AP4 was measured as 0.83. AP4 was returned to the reactor. Isopropyl acetate (450) was charged to the reactor. The reactor contents were mixed with an overhead stirrer, then the stirring was stopped and the layers were allowed to separate. The lower product-rich aqueous layer (AP5) and the upper organic layer (OP5) were collected. The pH of AP5 was measured as 1.90. AP5 was returned to the reactor. Isopropyl acetate (450) was charged to the reactor. The reactor contents were mixed with an overhead stirrer, and then the stirring was stopped to allow the layers to separate. The lower product-rich aqueous layer (AP6) and the upper organic layer (OP6) were collected. The pH of AP6 was measured as 3.1. AP6 was returned to the reactor, and the pH was adjusted to 5.8-6.2 (final pH 6.04) using 1% ammonia solution (35 mL). The temperature was maintained between 0-10°C during the pH adjustment.The reaction mixture was charged with water (approximately 820 mL) to a final volume of 1350 mL. The pH was measured again (5.83) and adjusted to 5.8-6.2 (6.01) using 1% ammonia solution (5 mL). The conductivity of the solution was measured as 15.29 mS / cm.

[0399] The crude plazomycin solution was loaded onto an XK-50 / 100 column packed with 325.5 g of CG-50 resin in the ammonium form with a water-filled headspace. The column temperature was stabilized at 27 °C. The crude solution was loaded in a downflow mode at a linear flow rate of 10-20 cm / h (approximately 9.2 mL / min). After the crude solution was loaded onto the resin bed, water (1 column volume, 1620 mL) was loaded in a downflow mode at a linear flow rate of 10-20 cm / h (9.2 mL / min). At the end of the water loading, 0.50% ammonia solution (prepared from 102 g of 25% ammonia in 5 L of water) was loaded onto the column in a downflow mode until plazomycin eluted from the column, as judged by the UV absorbance trace at 210 nm. The ammonia solution was loaded at a linear flow rate of 38 cm / h (12.4 mL / min). The product-rich fractions (#31–#45) were combined to yield 4072 mL of purified plazomycin free base solution. The ammonia content of the solution was measured by ion chromatography at 4060 μg / mL, and the plazomycin free base concentration was measured by UPLC at 1.52% w / v. This solution was treated by reverse osmosis using an XLE membrane in a dialysis mode until the ammonia (μg / mL) relative to plazomycin (% w / v) was less than 20. Five diavolumes of water were treated to achieve this criterion. The temperature was maintained below 10°C during the ammonia removal process via the dialysis process. After the ammonia removal process, the pH of the purified plazomycin solution was adjusted to 6.74 using 6 M sulfuric acid solution (56). The temperature during the pH adjustment was maintained between 0 and 5°C. The neutralized solution was passed through a pre-washed Zetacarbon R55 charcoal cartridge at a flow rate of 72 L / h.m2 (15 mL / min). After filtration, the cartridge was washed with water (1068 mL) and the wash was combined with the filtered plazomicin solution. The combined filtrate and wash were concentrated to 540 mL using reverse osmosis with an XLE membrane in nanofiltration mode. The concentrated solution was passed through a 0.22 micron filter and isolated by spray drying using a Buchi laboratory spray dryer (95.86 g, 0.114 mol, 76% yield).

[0400] According to a preferred embodiment of the present invention, for example, the following is provided: (Section 1) 1. A process for preparing a compound of formula (2) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, comprising: (a) A compound of formula (1): [ka] (1) or an enantiomer or a diastereomer thereof is contacted with 1-{[(p-nitrobenzyl)oxy]carbonyl}-1H-benzotriazole (PNZ-Bt) to obtain a compound of formula (2): [ka] (2) or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof, During the ceremony, [ka] is a single or double bond, R 1 is H or C1-C3 alkyl, R 2 is H or C1-C3 alkyl, R 3 is H or C1-C3 alkyl. (Section 2) Item 1, wherein step (a) is carried out in the presence of a solvent selected from the group consisting of dichloromethane, methanol, and combinations thereof. (Section 3) 3. The process according to item 1 or 2, wherein the PNZ-Bt is present in an amount of about 1.0 to 1.2 molar equivalents relative to the compound of formula (1) or its enantiomer or diastereomer. (Section 4) Step (b1) or (b2): (b1)R 1 , R 2 , and R3 is H, the compound of formula (2) may be contacted with a Boc protecting group reagent to provide a compound of formula (3): [ka] (3) or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof; (b2)R 1 , R 2 , or R 3 are independently C1-C3 alkyl, first remove the C1-C3 alkyl, and then contact the compound of formula (2), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, with a Boc protecting group reagent to obtain a compound of formula (3): [ka] (3) 4. The process according to any one of items 1 to 3, further comprising a step of obtaining the compound of formula (I), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. (Section 5) Item 5. The process according to item 4, wherein the Boc protecting group reagent is Boc2O or Boc-ONb. (Section 6) 6. The process according to item 4 or 5, wherein step (b1) or (b2) is carried out in the presence of a Lewis acid. (Section 7) 7. The process of claim 6, wherein the Lewis acid is Zn(OAc)2, ZnCl2, or Zn(OPiv)2. (Section 8) Item 9. The process according to item 6, wherein the Lewis acid comprises copper ions or nickel ions. 9. The process according to any one of items 4 to 8, wherein step (b1) or (b2) is carried out in the presence of triethylamine. (Section 10) Any of the above items 4 to 8, wherein step (b1) or (b2) is carried out in the presence of methanol. The process of any one of claims 1 to 4. (Section 11) (c) a compound of the formula (3), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, [ka] to produce a compound of formula (4): [ka] (4) 11. The process according to any one of items 4 to 10, further comprising obtaining a compound of formula (I) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. (Section 12) Item 12. The process according to item 11, wherein step (c) is carried out in the presence of an activating reagent and a peptide coupling reagent. (Section 13) Item 13. The process according to item 12, wherein the activating reagent is HOBt. (Section 14) The activating reagent is [ka] Item 14. The process according to item 13, wherein the compound is present in an amount of about 0.05 to 1.0 molar equivalents relative to the compound. (Section 15) 13. The process according to item 12, wherein the peptide binding reagent is EDAC or PyBOP. (Section 16) the peptide binding reagent [ka] Item 16. The process according to item 15, wherein the compound is present in an amount of about 1.0 to 1.4 molar equivalents relative to the compound. (Section 17) 17. The process according to any one of items 11 to 16, wherein step (c) is carried out under acidic conditions. (Section 18) Item 18. The process according to item 17, wherein the acidic conditions are about pH 4 to 7. (Section 19) Item 18. The process according to item 17, wherein the acidic conditions are about pH 5. (Section 20) 20. The process according to any one of items 11 to 19, further comprising preparing a crystalline form of the compound of formula (4), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. (Section 21) 21. The process according to any one of items 11 to 20, further comprising isolating the compound of formula (4), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. (Section 22) (d) contacting the compound of formula (4), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, with a Boc protecting group reagent to obtain a compound of formula (5): [ka] (5) 22. The process according to any one of items 11 to 21, further comprising obtaining a compound of formula (I) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. (Section 23) 23. The process according to item 22, wherein the Boc protecting group reagent is Boc2O. (Section 24) 24. The process according to paragraph 22 or 23, wherein step (d) is carried out in the presence of an alcohol. (Section 25) 25. The process according to claim 24, wherein the alcohol is methanol. (Section 26) 26. The process of any one of paragraphs 22 to 25, wherein step (d) is carried out at a temperature of up to about 60°C. (Section 27) (e) contacting the compound of formula (5), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, with a PNZ deprotecting reagent to obtain a compound of formula (6): [ka] (6) 27. The process according to any one of items 22 to 26, further comprising obtaining a compound of formula (I) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. (Section 28) 28. The process of claim 27, wherein the PNZ deprotection reagent is sodium dithionite. (Section 29) 29. The process according to item 27 or 28, further comprising preparing a crystalline form of the compound of formula (6), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. (Section 30) 30. The process according to any one of items 27 to 29, further comprising isolating the compound of formula (6), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. (Section 31) (f) a compound of the formula (6), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, [ka] (In the formula, LG 1 is a leaving group) to produce a compound of formula (7): [ka] (7) 31. The process according to any one of items 27 to 30, further comprising obtaining a compound of formula (I) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. (Section 32) 32. The process of claim 31, wherein the leaving group is iodo. (Section 33) The aforementioned [ka] 32. The process according to item 31, wherein is present in an amount of about 1.0 to 1.5 molar equivalents relative to the compound of formula (6). (Section 34) 34. The process according to any one of items 31 to 33, wherein step (f) is carried out under substantially water-free conditions. (Section 35) 35. The process according to any one of items 31 to 34, wherein step (f) is carried out in the presence of a solvent selected from the group consisting of acetonitrile, acetone, and combinations thereof. (Section 36) 36. The process according to any one of the above paragraphs 31 to 35, wherein step (f) is carried out in the presence of NaHCO3. (Section 37) 37. The process according to any one of the above paragraphs 31 to 36, wherein step (f) is carried out at a temperature of about 30°C to 40°C. (Section 38) 38. The process of any one of paragraphs 31 to 37, further comprising adding 1,4-diazabicyclo[2.2.2]octane (DABCO) to the reaction mixture. (Section 39) 39. The process according to any one of the above items 31 to 38, further comprising preparing a crystalline form of the compound of formula (7), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. (Section 40) 40. The process according to any one of items 31 to 39, further comprising isolating the compound of formula (7), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. (Section 41) (g) contacting the compound of formula (7), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, with a Boc removal reagent to obtain a compound of formula (8): [ka] (8) 41. The process according to any one of items 31 to 40, further comprising obtaining a compound of formula (I) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. (Section 42) The Boc-removal reagent is TFA, thereby obtaining a TFA salt of the compound of formula (8) or a solvate thereof or an enantiomer thereof or a diastereomer thereof. Item 42. The process of paragraph 41. (Section 43) 43. The process according to item 42, further comprising removing the TFA salt to obtain a compound of formula (8), or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. (Section 44) 44. The process according to item 41 or 43, further comprising (h) salt formation with an acid to obtain a salt of the compound of formula (8) or a solvate thereof or an enantiomer thereof or a diastereomer thereof. (Section 45) The acid in step (h) is sulfuric acid, thereby producing the sulfate salt of the compound of formula (9): [ka] 45. The process according to the above item 44, wherein x is 1 to 5, or a solvate thereof, an enantiomer thereof, or a diastereomer thereof is obtained. (Section 46) R 1 , R 2 , or R 3 The process according to any one of items 1 to 3, wherein is H. (Section 47) [ka] 47. The process according to any one of items 1 to 46, wherein is a double bond. (Section 48) The stereochemistry at carbon atoms 1, 3, 4, 5, 6, 1', 2', 1", 2", 3", and 4" in formulas (1) to (3) is shown as in formula (X), [ka] indicates a point of attachment to a hydrogen or moiety; [ka] (X). (Section 49) The stereochemistry at carbon atoms 1, 3, 4, 5, 6, 1', 2', 1", 2", 3", 4", and 1-z in formulas (4) to (9) is shown as in formula (Y), [ka] 48. The process according to any one of the above paragraphs 11 to 47, wherein represents a point of attachment to a hydrogen or moiety: [ka] (Y). (Section 50) Compound of formula (5): [ka] (5) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, said process comprising: (a) A compound of formula (4): [ka] (4) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, with a Boc protecting group reagent, wherein [ka] is a single or double bond. (Section 51) The compound of formula (4), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, is a compound of formula (3): [ka] (3) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, [ka] 51. The process according to claim 50, wherein the compound is prepared by contacting the compound with (Section 52) The compound of the formula (3), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, (b1) A compound of formula (2a): [ka] (2a), or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof with a Boc protecting group reagent; or (b2) A compound of formula (2): [ka] (2) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, wherein C1-C3 alkyl is removed (In the formula, R 1 is H or C1-C3 alkyl, and R 2 is H or C1-C3 alkyl, and R 3 is H or C1-C3 alkyl, and R 1 , R 2 , or R 3 one or more of which are independently C1-C3 alkyl; 52. The process according to item 51, wherein the compound of formula (2) is then contacted with a Boc protecting group reagent to prepare the compound. (Section 53) The compound of formula (2), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, is a compound of formula (1): [ka] (1) 53. The process according to claim 52, wherein the compound is prepared by contacting the compound (I) with 1-{[(p-nitrobenzyl)oxy]carbonyl}-1H-benzotriazole (PNZ-Bt), or an enantiomer or a diastereomer thereof. (Section 54) 54. The process according to any one of items 50 to 53, wherein the Boc protecting group reagent is Boc2O. (Section 55) 55. The process according to any one of the above paragraphs 50 to 54, wherein step (a), (b1), or (b2) is carried out in the presence of an alcohol. (Section 56) 56. The process of claim 55, wherein the alcohol is methanol. (Section 57) 57. The process of any one of paragraphs 50 to 56, wherein step (a), (b1), or (b2) is carried out at a temperature of up to about 60°C. (Section 58) (e) contacting the compound of formula (5), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, with a PNZ deprotecting reagent to obtain a compound of formula (6): [ka] (6) 58. The process according to any one of items 50 to 57, further comprising obtaining a compound of formula (I) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. (Section 59) 59. The process of claim 58, wherein the PNZ deprotection reagent is sodium dithionite. (Section 60) 60. The process according to any one of paragraphs 50 to 59, further comprising preparing a crystalline form of the compound of formula (6), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. (Section 61) 61. The process according to any one of items 50 to 60, further comprising isolating the compound of formula (6), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. (Section 62) (f) the compound of formula (6) [ka] (In the formula, LG 1 is a leaving group) to produce a compound of formula (7): [ka] (7) 62. The process according to any one of items 50 to 61, further comprising obtaining a compound of formula (I) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. (Section 63) 63. The process of claim 62, wherein the leaving group is iodo. (Section 64) [ka] Item 63. The process according to item 62, wherein is present in an amount of about 1.0 to 1.5 molar equivalents relative to the compound of formula (6). (Section 65) 65. The process according to any one of the above paragraphs 62 to 64, wherein step (f) is carried out under substantially water-free conditions. (Section 66) 66. The process according to any one of the above paragraphs 62 to 65, wherein step (f) is carried out in the presence of a solvent selected from the group consisting of acetonitrile, acetone, and combinations thereof. (Section 67) 67. The process of any one of paragraphs 62 to 66, wherein step (f) is carried out in the presence of NaHCO3. (Section 68) 68. The process of any one of paragraphs 62 to 67, wherein step (f) is carried out at a temperature of about 30°C to 40°C. (Section 69) 69. The process of any one of paragraphs 62 to 68, further comprising adding 1,4-diazabicyclo[2.2.2]octane (DABCO) to the reaction mixture. (Section 70) 70. The process according to any one of paragraphs 62 to 69, further comprising preparing a crystalline form of the compound of formula (7), or a salt thereof, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. (Section 71) 71. The process according to any one of items 62 to 70, further comprising isolating the compound of formula (7), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. (Section 72) (g) contacting the compound of formula (7), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, with a Boc removal reagent to obtain a compound of formula (8): [ka] (8) 72. The process according to any one of items 62 to 71, further comprising obtaining a compound of formula (I) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof. (Section 73) 73. The process according to the above item 72, wherein the Boc removal reagent is TFA, thereby obtaining a TFA salt of the compound of formula (8) or a solvate thereof or an enantiomer thereof or a diastereomer thereof. (Section 74) 74. The process according to item 73, further comprising removing the TFA salt to obtain a compound of formula (8), or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. (Section 75) 75. The process according to item 72 or 74, further comprising (h) salt formation with an acid to obtain a salt of the compound of formula (8) or a solvate thereof or an enantiomer thereof or a diastereomer thereof. (Section 76) The acid in step (h) is sulfuric acid, thereby producing the sulfate salt of the compound of formula (9): [ka] 76. The process according to item 75, wherein x is 1 to 5, or a solvate thereof, or an enantiomer thereof, or a diastereomer thereof. (Section 77) Compound of formula (7): [ka] (7) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, said process comprising: (f) a compound of formula (6), [ka] (6) or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof, [ka] wherein LG 1 is the leaving group, [ka] is a single or double bond. (Section 78) A compound of the formula (6), a salt thereof, a solvate thereof, or an enantiomer thereof or a diastereomer thereof, is a compound of formula (5): [ka] (5) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, Item 79. The process of claim 77, wherein the compound is prepared by contacting the compound with a PNZ deprotection reagent. The compound of formula (5), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, is a compound of formula (4): [ka] (4) 79. The process according to item 78, wherein the compound is prepared by contacting a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof with a Boc protecting group reagent. (Section 80) The compound of formula (4), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, is a compound of formula (3): [ka] (3) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, [ka] 80. The process according to claim 79, wherein the compound is prepared by contacting the compound with (Section 81) The compound of the formula (3), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, (b1) A compound of formula (2a): [ka] (2a), or a salt thereof or a solvate thereof or an enantiomer thereof or a diastereomer thereof with a Boc protecting group reagent; or (b2) A compound of formula (2): [ka] (2) or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, wherein C1-C3 alkyl is removed (In the formula, R 1 is H or C1-C3 alkyl, and R 2 is H or C1-C3 alkyl, and R 3 is H or C1-C3 alkyl, and R 1 , R 2 , or R 3 one or more of which are independently C1-C3 alkyl; The process according to paragraph 80 above, wherein the compound of formula (2) is then prepared by contacting the compound with a Boc protecting group reagent. (Section 82) The compound of formula (2), or a salt thereof, a solvate thereof, an enantiomer thereof, or a diastereomer thereof, is a compound of formula (1): [ka] (1) 82. The process of claim 81, wherein the compound is prepared by contacting 1-{[(p-nitrobenzyl)oxy]carbonyl}-1H-benzotriazole (PNZ-Bt) with 1-{[(p-nitrobenzyl)oxy]carbonyl}-1H-benzotriazole (PNZ-Bt). (Section 83) 83. The process according to any one of paragraphs 77 to 82, wherein the leaving group is iodo. (Section 84) [ka] Item 84. The process according to item 83, wherein is present in an amount of about 1.0 to 1.5 molar equivalents relative to the compound of formula (6). (Section 85) 85. The process according to any one of the above paragraphs 77 to 84, wherein step (f) is carried out under substantially water-free conditions. (Section 86) 86. The process of any one of paragraphs 77 to 85, wherein step (f) is carried out in the presence of a solvent selected from the group consisting of acetonitrile, acetone, and combinations thereof. (Section 87) 87. The process ...

Claims

[Claim 1] The invention as depicted in the drawings.

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