TLR7 agonists

Abstract

The present invention relates to TLR7 agonists of formula I and their use in the treatment of diseases such as cancer and infectious diseases.

Description

Technical Field

[0001] The present invention provides TLR7 agonists and their use in therapeutic applications. The present invention provides methods of using TLR7 agonists to treat infections, immune disorders and cancer. Background Art

[0002] The ultimate goal of cancer immunotherapy is to eradicate tumor cells through the immune system. Both the innate and adaptive arms of the immune system can contribute to the elimination of tumor cells, with natural killer (NK) cells and T cells being key players, respectively. The key to the adaptive immune response to tumor cells is the activation of CD8+ cytotoxic T lymphocytes (CTLs), which can utilize their cytotoxic potential against tumor cells after recognizing tumor-associated antigens (TAAs). The activation of naive CD8+ cells is carried out by antigen presenting cells (APCs), and dendritic cells (DCs) are considered to be the most specialized APCs. These cells capture and process TAAs, presenting epitopes and histocompatibility complex (MHC) molecules on their membranes. The maturation of APCs based on danger signals is crucial for presentation to T cells in a stimulatory manner.

[0003] Although TAA-specific T cells have the potential to eliminate tumor cells, the tolerance of peripheral T cells to TAAs prevents an effective immune response to tumors. Methods for breaking T cell tolerance to TAAs can be divided into two categories: (a) active specific immunotherapy (also known as cancer vaccines) and (b) passive specific immunotherapy (through adoptive transfer of anti-tumor T cells or through monoclonal antibodies). The low immunogenicity of tumor cells is also a potential problem for cancer immunotherapy. The reason for this low immunogenicity is that TAAs are mainly self-antigens, and also due to the downregulation of human leukocyte antigens and co-stimulatory molecules on the tumor cell membrane. Moreover, tumor cells actively suppress the immune system by secreting immunosuppressive molecules that interfere with DC and T cell function.

[0004] Toll-like receptors (TLRs) are a class of proteins that play a key role in the innate immune system. TLRs are pattern recognition receptors (PRRs) that recognize molecules that are widely shared by pathogens but distinct from host molecules, collectively known as pathogen-associated molecular patterns (PAMPs). They are single, transmembrane, non-catalytic receptors, typically expressed on sentinel cells such as macrophages and dendritic cells, that recognize structurally conserved molecules derived from microorganisms.

[0005] TLR 3, 7, 8, and 9 form a group of intracellular TLRs and recognize bacterial or viral nucleic acids. The natural ligands of TLR7 and TLR8 are single-stranded RNAs rich in guanosine and / or uridine. TLR7 and TLR8 are also activated by certain small synthetic compounds. Imidazoloquinoline derivatives imiquimod (R837) and resiquimod (R848) are described as TLR7 ligands in mice (Hemmi et al., 2002, Nat. Immunol. 3: 196–200). In addition, the guanosine analogue loxoribine is identified as a TLR7 ligand (Heil et al., 2003, Eur. J. Immunol. 33: 2987–2997). Other TLR7 and / or TLR8 ligands include CL097 (3M-001), 852A and CL075.

[0006] Although TLR7 and TLR8 are structurally similar, their activation has distinct effects on innate immune cells and subsequent cytokine production. TLR8 agonists have been reported to be more effective than TLR7 agonists in inducing proinflammatory cytokines and chemokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-12, and macrophage inflammatory protein (MIP)-1α in peripheral blood mononuclear cells (PBMCs). Conversely, TLR7 agonists have been reported to activate plasmacytoid dendritic cells and induce interferon (IFN)-α production.

[0007] After the discovery of the efficacy of the TLR7 / 8 agonist imiquimod in protecting guinea pigs from herpesvirus infection, imiquimod has also been shown to be effective against several transplantable murine tumors. Clinical responsiveness to topical treatment with imiquimod (a topical cream) was effective for both primary skin tumors and skin metastases. In these reports, the immune-enhancing effects of imiquimod were sufficient to elicit an antitumor response without the addition of a TAA. Imiquimod treatment has also been reported to be associated with partial or complete reversal of the abnormal expression of certain genes in premalignant actinic keratoses, demonstrating the ability of imiquimod to prevent cancer development.

[0008] Although treatment with TLR7 agonists in localized cancers has shown promising anticancer effects, administration of these agonists by oral or systemic routes remains challenging. In a phase II clinical study in patients with hepatitis C virus infection, R848 was administered by the oral route and showed a therapeutic effect on plasma hepatitis virus titers, but with dose-limiting toxicity. In another study, the TLR7 agonist 852A was tested in patients with metastatic melanoma in a phase II study with three weeks of intravenous dosing. The study showed prolonged disease stabilization and elevated serum IFNα and IP-10 in some patients, but two patients had dose-limiting toxicity. These studies suggest that systemic use of TLR7 agonists in patients may be a challenge due to the narrow therapeutic window. Summary of the invention

[0009] The present invention generally relates to compounds useful as TLR7 agonists, compositions thereof, methods of making thereof, and methods of using thereof.

[0010] In one embodiment, the present invention relates to a TLR7 agonist compound according to formula I:

[0011]

[0012] in

[0013] R 1 Yes –H, –OH, -OC(O)-R 6 or –F,

[0014] R 2 is –H or –F,

[0015] R 3 are independently –OH or –OC(O)-R 7 ,

[0016] R 4 Yes – (C 1 -C 8 )alkyl, –(C 1 -C 8 ) alkenyl, –(C 1 -C 8 ) alkynyl, –(C 1 -C 8 ) haloalkyl, –(CH 2 ) n (cycloalkyl), –(CH 2 ) n (heterocyclic group), –(CH 2 ) n (aryl), –(CH 2 ) n (heteroaryl) or –(CH2 ) n C(O)OR 6 ,

[0017] R 5 It is –H, –OH, -OCH 3 , –SH or –Cl,

[0018] R 6 and R 7 Independently for –(C 1 -C 8 ) alkyl or aryl,

[0019] n is an integer of 1, 2, 3, 4 or 5,

[0020] wherein each alkyl, cycloalkyl, alkenyl, alkynyl, haloalkyl, aryl, heteroaryl and heterocyclyl is independently substituted by CN, NO 2 , halogen, (C 1 -C 3 ) alkyl, (C 1 -C 3 ) haloalkyl, aryl, heteroaryl, OH, alkenyl, alkynyl, O-(C 1 -C 3 )alkyl, O-(alkylene)aryl, O-(alkylene)heteroaryl, C(O)R 8 、S(C 1 -C 8 )alkyl, S(O)alkyl, SO 2 Alkyl, C(O)OR 8 、C(O)NR 8 R 8 、C(O)NR 8 SO 2 Alkyl, NR 8 R 8 NR 8 (CO)OR 8 NH(CO)R 8 NH(SO 2 )alkyl or NH(SO 2 )NR 8 R 8 is optionally substituted, and R 8 are independently -H, -OH, -(C 1 -C 8 )alkyl, cycloalkyl, heterocyclyl, or C(O)NR 8 R 8 or NR 8 R 8 The two R's 8 Combined with nitrogen atoms to form heterocyclic rings;

[0021] or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate or a pharmaceutically acceptable hydrate thereof.

[0022] In other embodiments, the TLR7 agonist compounds of the present invention may be used alone, or in combination with other additional therapeutic agents and treatment procedures, to treat or prevent cancer or infection or infectious disease in a subject in need of such treatment or prevention.

[0023] In other embodiments, the present invention provides a pharmaceutical composition comprising: (i) a therapeutically effective amount of at least one compound of Formula I or a stereoisomer, tautomer or pharmaceutically acceptable salt thereof; (ii) in combination with a pharmaceutically acceptable carrier, diluent or excipient. Pharmaceutical compositions comprising a pharmaceutically acceptable carrier, diluent, or excipient and other therapeutic agents are also part of the present invention.

[0024] The above embodiments and other aspects of the invention are apparent in the following detailed description of the invention.To this end, various references are set forth herein that describe certain background information, procedures, compounds and / or compositions in more detail, and each is incorporated herein by reference in its entirety. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention provides compounds that are TLR7 agonists. The present invention includes TLR7 agonists that activate TLR7 without substantially activating TLR8.

[0027] definition

[0028] In order to make the present invention more easily understood, some technical terms are specifically defined below. Unless specifically defined elsewhere herein, all other technical and scientific terms used herein have the meanings commonly understood by ordinary technicians in the field to which the present invention belongs.

[0029] In the following description, in order to provide a thorough understanding of the various embodiments of the present invention, many specific details are set forth. However, those skilled in the art will appreciate that the present invention can be practiced without these details. Unless the context otherwise requires, in this specification and claims, the words "comprise" and its variants such as "contain" and "comprises" should be interpreted in an open, inclusive sense (i.e., "including but not limited to").

[0030] The reference to "one embodiment" or "an embodiment" in the specification indicates that the specific features, structures, or properties described in conjunction with the embodiment are included in at least one embodiment of the present invention. Therefore, the phrases "in one embodiment" or "in an embodiment" appearing in various places in the specification do not necessarily all refer to the same embodiment. Moreover, the specific features, structures, or properties may be combined in any suitable manner in one or more embodiments.

[0031] As used herein, including the appended claims, singular forms of words such as "a," "an," and "the" include their corresponding plural referents unless the context clearly dictates otherwise.

[0032] "Administering" and "treating" as applied to an animal, human, subject, cell, tissue, organ or biological fluid, refers to the contact of an exogenous drug, therapeutic agent, diagnostic agent or composition with an animal, human, subject, cell, tissue, organ or biological fluid. Treatment of cells includes contact of an agent with a cell and contact of an agent with a fluid, wherein the fluid is in contact with the cell. "Administering" and "treating" also refer to in vitro and ex vivo treatment of a cell, for example, by an agent, diagnostic, binding compound or by another cell.

[0033] "Treatment" or "treatment" refers to the internal or external administration of a therapeutic agent with therapeutic activity, such as a composition comprising any of the antibodies or antigen-binding fragments of the present invention, to a subject or patient having one or more symptoms of a disease or suspected of having a disease. Typically, the therapeutic agent is administered in an amount effective to alleviate one or more symptoms of the disease in the subject or population being treated, whether by inducing regression of such symptoms or inhibiting them to any clinically measurable degree. The amount of the therapeutic agent effective to alleviate any particular disease symptom may vary according to factors such as the patient's disease state, age, and weight, and the ability of the drug to elicit a desired response in the subject. Whether the disease symptom is alleviated can be assessed by any clinical measurement method commonly used by a physician or other skilled healthcare provider to assess the severity or progression of the symptom.

[0034] "Amino" refers to -NH 2 Substituent.

[0035] “Aminocarbonyl” refers to –C(O)NH 2 Substituent.

[0036] "Carboxyl" refers to -CO 2 H substituent.

[0037] "Carbonyl" refers to a -C(O)- or -C(=O)- group. Both symbols are used interchangeably in the specification.

[0038] "Cyano" refers to a -C≡N substituent.

[0039] "Acetyl" refers to -C(O)CH 3 Substituent.

[0040] "Hydroxy" refers to an -OH substituent.

[0041] "Oxo" refers to a =0 substituent.

[0042] "Thiol" or "sulfhydryl" refers to a -SH substituent.

[0043] "Alkyl" refers to a saturated, straight or branched hydrocarbon chain radical consisting solely of carbon and hydrogen atoms, having from one to twelve carbon atoms (C 1 -C 12 Alkyl), one to eight carbon atoms (C 1 -C 8 Alkyl) or one to six carbon atoms (C 1 -C 6 Alkyl) is connected to the rest of the molecule by a single bond. Exemplary alkyls include methyl, ethyl, n-propyl, 1-methylethyl (isopropyl), n-butyl, n-pentyl, 1,1-dimethylethyl (tert-butyl), 3-methylhexyl, 2-methylhexyl, etc. The portion that can be substituted by the alkyl is selected from, but not limited to, hydroxyl, amino, alkylamino, arylamino, alkoxy, thioalkoxy, aryloxy, nitro, cyano, sulfonic acid, sulfate, phosphonic acid, phosphate or phosphonate, as known to those skilled in the art, can be unprotected or protected as needed, for example, as described by Greene et al. in Protective Groups in Organic Synthesis (John Wiley and Sons, Second Edition, 1991).

[0044] "Lower alkyl" has the same meaning as alkyl defined above, but has one to three carbon atoms (C 1 -C 3 alkyl).

[0045] "Alkenyl" refers to a group having at least one double bond and from two to twelve carbon atoms (C 2 -C 12 alkenyl), two to eight carbon atoms (C 2 -C 8 alkenyl), or two to six carbon atoms (C 2 -C 6 The invention also includes an unsaturated alkyl group which is an alkylene group (e.g., an alkylene group such as vinyl, propenyl, butenyl, pentenyl, hexenyl, etc.) and which is attached to the rest of the molecule by a single bond, such as ethenyl, propenyl, butenyl, pentenyl, hexenyl, etc.

[0046] "Alkynyl" refers to a radical having at least one triple bond and from two to twelve carbon atoms (C 2 -C 12 Alkynyl), two to ten carbon atoms (C 2 -C 10 Alkynyl), two to eight carbon atoms (C 2 -C 8 Alkynyl), or two to six carbon atoms (C 2 -C 6 alkynyl) and which is attached to the rest of the molecule by a single bond, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, and the like.

[0047] "Alkylidene" or "alkylene chain" refers to a straight or branched divalent hydrocarbon (alkyl) chain consisting only of carbon and hydrogen that connects the rest of the molecule to a radical. An alkylene group can have from one to twelve carbon atoms, such as methylene, ethylene, propylene, n-butylene, etc. The alkylene chain is connected to the rest of the molecule by a single bond or a double bond. The points of attachment of the alkylene chain to the rest of the molecule can be through one carbon or any two carbons in the chain. "Optionally substituted alkylene" refers to an alkylene or substituted alkylene group.

[0048] "Alkoxy" refers to a group of the formula -OR a A group in which R a is an alkyl group as defined above with the specified number of carbon atoms. Examples of alkoxy groups include, but are not limited to, -O-methyl (methoxy), -O-ethyl (ethoxy), -O-propyl (propoxy), -O-isopropyl (isopropoxy), and the like.

[0049] "Aryl" refers to a hydrocarbon ring system radical comprising hydrogen, 6 to 18 carbon atoms, and at least one aromatic ring. Exemplary aryl groups are hydrocarbon ring system radicals comprising hydrogen and 6 to 9 carbon atoms and at least one aromatic ring; hydrocarbon ring system radicals comprising hydrogen and 9 to 12 carbon atoms and at least one aromatic ring; hydrocarbon ring system radicals comprising hydrogen and 12 to 15 carbon atoms and at least one aromatic ring; or hydrocarbon ring system radicals comprising hydrogen and 15 to 18 carbon atoms and at least one aromatic ring. For purposes of the present invention, an aryl group may be a monocyclic, bicyclic, tricyclic, or tetracyclic ring system, which may include fused or bridged ring systems. Aryl groups include, but are not limited to, groups derived from aceanthrylene, acenaphthylene, acephenanthrylene, anthracene, azulene, benzene, The term "optionally substituted aryl" refers to an aryl group or a substituted aryl group. The aryl group may be substituted with, but is not limited to, one or more of hydroxyl, amino, alkylamino, arylamino, alkoxy, aryloxy, nitro, cyano, sulfonic acid, sulfate, phosphonic acid, phosphate or phosphonate, and may be unprotected or protected as needed, as described by Greene et al. in Protective Groups in Organic Synthesis (John Wiley and Sons, 2nd edition, 1991).

[0050] "Cycloalkyl" refers to a stable non-aromatic monocyclic or polycyclic hydrocarbon radical consisting only of carbon and hydrogen atoms, which may include a fused ring or bridged ring system having three to fifteen carbon atoms, preferably three to ten carbon atoms, three to nine carbon atoms, three to eight carbon atoms, three to seven carbon atoms, three to six carbon atoms, three to five carbon atoms, a ring having four carbon atoms, or a ring having three carbon atoms. The cycloalkyl ring may be saturated or unsaturated and is connected to the rest of the molecule by a single bond. Monocyclic groups include, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl. Polycyclic groups include, for example, adamantyl, norbornyl, decahydronaphthyl, 7,7-dimethyl-bicyclo[2.2.1]heptyl, etc.

[0051] "Fused" means that any ring structure described herein is fused to an existing ring structure of a compound of the invention. When the fused ring is a heterocyclyl ring or a heteroaryl ring, any carbon atom on the existing ring structure that becomes part of the fused heterocyclyl ring or the fused heteroaryl ring may be substituted with a nitrogen atom.

[0052] "Halogen" or "halo" refers to bromine, chlorine, fluorine or iodine.

[0053] As defined herein, "haloalkyl" refers to an alkyl group with a specified number of carbon atoms, wherein one or more hydrogen atoms of the alkyl group are replaced by a halogen (halo) as defined above. The halogen atoms may be the same or different. Exemplary haloalkyl groups are trifluoromethyl, difluoromethyl, trichloromethyl, 2,2,2-trifluoroethyl, 1,2-difluoroethyl, 3-bromo-2-fluoropropyl, 1,2-dibromoethyl, etc.

[0054] "Heterocyclyl" or "heterocycle" refers to a stable 3-18-membered saturated or unsaturated group consisting of two to twelve carbon atoms and one to six heteroatoms selected from nitrogen, oxygen and sulfur, for example, one to five heteroatoms, one to four heteroatoms, one to three heteroatoms, or one to two heteroatoms. Exemplary heterocycles include, but are not limited to, a stable 3-15-membered saturated or unsaturated group, a stable 3-12-membered saturated or unsaturated group, a stable 3-9-membered saturated or unsaturated group, a stable 8-membered saturated or unsaturated group, a stable 7-membered saturated or unsaturated group, a stable 6-membered saturated or unsaturated group, or a stable 5-membered saturated or unsaturated group.

[0055] Unless otherwise specifically stated in the specification, the heterocyclyl group may be a monocyclic, bicyclic, tricyclic or tetracyclic ring system, which may include fused or bridged ring systems; the nitrogen atom, carbon atom or sulfur atom in the heterocyclyl group may be optionally oxidized; the nitrogen atom may be optionally quaternized; the heterocyclyl group may be partially or fully saturated. Examples of non-aromatic heterocyclic groups include, but are not limited to, azetidinyl, dioxolanyl, thienyl [1,3] dithienyl, decahydroisoquinolinyl, imidazolinyl, imidazolidinyl, isothiazolidinyl, isoxazolidinyl, morpholinyl, octahydroindolyl, octahydroisoindolyl, 2-piperazinyl, 2-piperidinyl, 2-pyrrolidinyl, oxazolidinyl, piperidinyl, piperazinyl, 4-piperidonyl, pyrrolidinyl, pyrazolidinyl, quinuclidine, thiazolidinyl, tetrahydrofuranyl, thietanyl, trithienyl, tetrahydropyranyl, thiomorpholinyl, thiamorpholinyl (thiamorpholinyl), 1-oxo-thiomorpholinyl, and 1,1-dioxo-thiomorpholinyl. Heterocyclic groups include heteroaryls as defined herein, and examples of aromatic alkyls are listed in the definition of heteroaryls below.

[0056] "Heteroaryl" refers to a 5- to 14-membered ring system radical containing hydrogen atoms, one to thirteen carbon atoms, one to six heteroatoms, and at least one aromatic ring, wherein the heteroatoms are selected from nitrogen, oxygen, and sulfur. For the purposes of the present invention, a heteroaryl group can be a stable 5-12 membered ring, a stable 5-10 membered ring, a stable 5-9 membered ring, a stable 5-8 membered ring, a stable 5-7 membered ring, or a stable 6 membered ring containing at least 1 heteroatom, at least 2 heteroatoms, at least 3 heteroatoms, at least 4 heteroatoms, at least 5 heteroatoms, or at least 6 heteroatoms. A heteroaryl group can be a monocyclic, bicyclic, tricyclic, or tetracyclic ring system, which may include fused or bridged ring systems; the nitrogen, carbon, or sulfur atoms in the heteroaryl group can be optionally oxidized; and the nitrogen atom can be optionally quaternized. The heteroatoms can be members of aromatic or non-aromatic rings, but at least one ring in the heteroaryl group is aromatic. Examples include, but are not limited to, aza benzo[b][1,4]dioxepinyl, 1,4-benzodioxanyl, benzonaphthofuranyl, benzoxazolyl, benzodioxanolyl, benzodioxinyl, benzopyranyl, benzopyrone, benzofuranyl, benzofuranone, benzothiophenyl, benzotriazolyl, benzo[4,6]imidazo[1,2-a]pyridinyl, carbazolyl, cinnolinyl, dibenzofuranyl, dibenzothiophenyl, furanyl, furanyl oxazolyl, oxadiazolyl, oxazolyl, oxadiazolyl, oxazolyl, oxadiazolyl, oxazolyl, oxadiazolyl, oxadiazinyl, ox ...

[0057] The compounds of the present invention may exhibit tautomerism. Although Formula I does not explicitly represent all possible tautomeric forms, it should be understood that Formula I is intended to represent any tautomeric form of the depicted compound and is not limited to the specific compound form depicted by the formula. For example, when R 5 When OH is present, for Formula I, it is understood that whether the substituents are shown in their enol or keto form as shown below, they represent the same compound. It is obvious to those skilled in the art that compounds such as Compound 1:

[0058]

[0059] Can exist in tautomeric forms such as compounds 1A and 1B:

[0060]

[0061] "Isolated nucleic acid molecule" or "isolated polynucleotide" refers to genomic DNA or RNA, mRNA, cDNA or a synthetic source or some combination thereof, which is unrelated to all or part of an isolated polynucleotide found in nature, or is related to an unrelated polynucleotide in nature. For the purposes of this disclosure, it is understood that a nucleic acid molecule "comprising" a particular nucleotide sequence does not comprise a complete chromosome. In addition to the particular sequence, an isolated nucleic acid molecule "comprising" a particular nucleic acid sequence may include coding sequences for up to ten or up to twenty or more other proteins or portions or fragments thereof, or may include operably linked regulatory sequences that control the expression of the coding region of the nucleic acid sequence, and / or may include vector sequences.

[0062] The phrase "control sequence" refers to DNA sequences necessary for the expression of an operably linked coding sequence in a particular host organism. Suitable control sequences for prokaryotes include, for example, a promoter, an optional operator sequence, and a ribosome binding site. Eukaryotic cells are known to use promoters, polyadenylation signals, and enhancers.

[0063] When a nucleic acid is placed in a functional relationship with another nucleic acid sequence, it is "operably linked". For example, if the DNA of a precursor sequence or secretory leader is expressed as a precursor protein that participates in the secretion of a polypeptide, it is operably linked to the DNA of the polypeptide; if a promoter or enhancer affects the transcription of a coding sequence, the promoter or enhancer is operably linked to the coding sequence; or if a ribosome binding site is positioned to facilitate translation, the nucleic acid body binding site is operably linked to the coding sequence. Usually, but not always, "operably linked" means that the DNA sequence being linked is continuous, and in the case of a secretory leader sequence, it is continuous and in the reading frame. However, enhancers do not have to be continuous. Connection is accomplished by connecting at convenient restriction sites. If there is no such site, a synthetic oligonucleotide adapter or joint is used according to conventional practice.

[0064] As used herein, the terms "cell," "cell line," and "cell culture" are used interchangeably, and all such designations include progeny. Thus, the words "transformants" and "transformed cells" include the primary subject cell and cultures derived therefrom, without regard to the number of passages. It is also understood that not all progeny will be precisely identical in DNA content, due to intentional or accidental mutations. Mutant progeny that have the same function or biological activity as screened for in the original transformed cell are included. If a different designation is intended, it will be clear from the context.

[0065] As used herein, "germline sequence" refers to the sequence of an unrearranged immunoglobulin DNA sequence. Any suitable source of unrecombined immunoglobulin sequences can be used. Human germline sequences can be obtained, for example, from the JOINSOLVER germline database on the website of the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the United States National Institutes of Health. Mouse germline sequences can be obtained, for example, as described in Giudicelli et al. (2005) Nucleic Acids Res. 33: D256-D261.

[0066] The term "in combination with..." means that the components administered in the method of the present invention can be formulated into a single composition for simultaneous delivery, or separately formulated into two or more compositions (e.g., a kit). Each component can be administered to a subject at a different time than the other components; for example, each administration can be provided non-simultaneously (e.g., separately or sequentially) at several intervals within a given time period. In addition, the separated components can be administered to a subject by the same or different routes.

[0067] As used herein, the term "effective amount" refers to the amount of a TLR7 agonist compound of the present invention, which, when administered alone or in combination with another therapeutic agent to a cell, tissue or subject, effectively causes a measurable improvement in one or more disease symptoms, such as cancer or cancer progression. An effective dose also refers to an amount of a compound or its pharmaceutical composition sufficient to at least partially improve symptoms (e.g., tumor reduction or elimination, insufficient tumor growth, prolonged survival). When it comes to administering a single active component alone, the effective dose refers only to that component. When applied to a combination, an effective dose refers to the combined amount of active ingredients that results in a therapeutic effect, whether administered in combination, continuously or simultaneously. An effective amount of treatment will result in an improvement in diagnostic measures or parameters of at least 10%; typically at least 20%; preferably at least about 30%; more preferably at least 40%, and most preferably at least 50%. In the case of using subjective indicators to assess the severity of the disease, the effective amount can also improve the subjective indicators.

[0068] A "subject" can be a mammal, such as a human, dog, cat, horse, cow, mouse, rat, monkey (eg, cynomolgous monkey, e.g., Macaca fascicularis), or rabbit. In a preferred embodiment of the invention, the subject is a human subject.

[0069] TLR7 agonists

[0070] One aspect of the present invention includes TLR7 agonist compounds of Formula I:

[0071]

[0072] in

[0073] R 1 Yes –H, –OH, -OC(O)-R 6 or –F,

[0074] R 2 is –H or –F,

[0075] R 3 are independently –OH or –OC(O)-R 7 ,

[0076] R 4 Yes – (C 1 -C 8 )alkyl, –(C 1 -C 8 ) alkenyl, –(C 1 -C 8 ) alkynyl, –(C 1 -C 8 ) haloalkyl, –(CH 2 ) n (cycloalkyl), –(CH 2 ) n (heterocyclic group), –(CH 2 ) n (aryl), –(CH 2 ) n (heteroaryl) or –(CH 2 ) n C(O)OR 6 ,

[0077] R 5 It is –H, –OH, -OCH 3 , –SH or –Cl,

[0078] R 6 and R 7 Independently for –(C 1 -C 8 ) alkyl or aryl,

[0079] n is an integer of 1, 2, 3, 4 or 5,

[0080] wherein each alkyl, cycloalkyl, alkenyl, alkynyl, haloalkyl, aryl, heteroaryl and heterocyclyl is independently substituted by CN, NO 2 , halogen, (C 1 -C 3) alkyl, (C 1 -C 3 ) haloalkyl, aryl, heteroaryl, OH, alkenyl, alkynyl, O-(C 1 -C 3 )alkyl, O-(alkylene)aryl, O-(alkylene)heteroaryl, C(O)R 8 、S(C 1 -C 8 )alkyl, S(O)alkyl, SO 2 Alkyl, C(O)OR 8 、C(O)NR 8 R 8 、C(O)NR 8 SO 2 Alkyl, NR 8 R 8 NR 8 (CO)OR 8 NH(CO)R 8 NH(SO 2 )alkyl or NH(SO 2 )NR 8 R 8 is optionally substituted, and R 8 are independently -H, -OH, -(C 1 -C 8 )alkyl, cycloalkyl, heterocyclyl, or C(O)NR 8 R 8 or NR 8 R 8 The two R's 8 Combined with nitrogen atoms to form heterocyclic rings;

[0081] or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate or a pharmaceutically acceptable hydrate thereof.

[0082] In one embodiment, R 1 is -H, -OH, or -F.

[0083] In one embodiment, R 1 It is -OH.

[0084] In one embodiment, R 1 Yes -H.

[0085] In one embodiment, R 1 Yes -F.

[0086] In one embodiment, R 2 Either -H or -F.

[0087] In one embodiment, R 2 Yes -H.

[0088] In one embodiment, R 2 Yes -F.

[0089] In one embodiment, R 3 Is -OH or -OC(O)-CH 3 .

[0090] In one embodiment, R 3 It is –OH.

[0091] In one embodiment, R 3 Yes-OC(O)-CH 3 .

[0092] In one embodiment, R 1 and R 3 is independently -OH.

[0093] In one embodiment, R 1 and R 3 are independently -OC(O)-CH 3 .

[0094] In one embodiment, R 4 Yes-(CH 2 )(cyclopropyl), -CH 2 C CH, -(CH 2 ) 3 CH 3 or -CH 2 CF 3 .

[0095] In one embodiment, R 4 Yes-(CH 2 )(cyclopropyl).

[0096] In one embodiment, R 4 Yes-CH 2 C CH.

[0097] In one embodiment, R 4 Yes-(CH 2 ) 3 CH 3 .

[0098] In one embodiment, R 4 Yes-CH 2 CF 3 .

[0099] In one embodiment, R 5 It is -H or -OH.

[0100] In one embodiment, R 5 Yes -H.

[0101] In one embodiment, R 5 It is -OH.

[0102] In one embodiment, R 7 Yes-(C 1 -C 8 )alkyl.

[0103] In one embodiment, R 7 Yes-CH 3 .

[0104] In one embodiment, R 8 It is -H, -OH, -CH 3 , or -CH 2 CH 3 .

[0105] In one embodiment, R 8 Yes -H.

[0106] In one embodiment, R 8 It is -OH.

[0107] In one embodiment, R 8 Yes-CH 3 .

[0108] In one embodiment, R 8 Yes-CH 2 CH 3 .

[0109] In one embodiment, the compound of Formula I is Compound 1, which can be referred to as 2-amino-7-(cyclopropylmethyl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)-tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0110] In another embodiment, the compound of Formula I is Compound 2, which can be referred to as 7-allyl-2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)-tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione; or 7-allyl-2-amino-9-(β-D-xylofuranosyl)-7,9-dihydro-1H-purine-6,8-dione, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0111] In one embodiment, the compound of formula I is compound 3, which can be referred to as 2-amino-7-(cyclopropylmethyl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)-tetrahydrofuran-2-yl)-7,9-dihydro-purin-8-one, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0112] In one embodiment, the compound of Formula I is Compound 4, which can be referred to as (2R, 3R, 4R, 5R)-2-(acetoxymethyl)-5-(2-amino-7-(cyclopropylmethyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetic acid diester, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0113] In one embodiment, the compound of Formula I is Compound 27, which can be referred to as 2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0114] In one embodiment, the compound of Formula I is Compound 30, which can be referred to as 2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0115] In one embodiment, the compound of Formula I is Compound 29, which can be referred to as ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)acetate, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0116] In one embodiment, the compound of Formula I is Compound 26, which can be referred to as 2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0117] In one embodiment, the compound of Formula I is Compound 32, which can be referred to as 2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0118] In one embodiment, the compound of Formula I is Compound 31, which can be referred to as ((2R,3R,4S,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)acetate, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0119] In one embodiment, the compound of Formula I is Compound 28, which can be referred to as 2-amino-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0120] In one embodiment, the compound of Formula I is Compound 32S, which can be referred to as 2-amino-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0121] In one embodiment, the compound of Formula I is Compound 31S, which can be referred to as ((2R,3S,4S,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)acetate, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0122] In one embodiment, the compound of Formula I is Compound 135, which can be referred to as 2-amino-7-butyl-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0123] In one embodiment, the compound of Formula I is Compound 337, which can be referred to as 2-amino-7-butyl-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0124] In one embodiment, the compound of Formula I is Compound 336, which can be referred to as ((2R,3R,4S,5R)-4-acetoxy-5-(2-amino-7-butyl-8-oxo-7,8-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)acetate, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0125] In one embodiment, the compound of Formula I is Compound 37, which can be referred to as 2-amino-7-butyl-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0126] In one embodiment, the compound of Formula I is Compound 225, which can be referred to as 2-amino-7-butyl-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0127] In one embodiment, the compound of Formula I is Compound 224, which can be referred to as ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-butyl-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)acetate, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0128] In one embodiment, the compound of Formula I is Compound 138, which can be referred to as 2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(2,2,2-trifluoroethyl)-7,9-dihydro-1H-purine-6,8-dione, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0129] In one embodiment, the compound of Formula I is Compound 343, which can be referred to as 2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(2,2,2-trifluoroethyl)-7,9-dihydro-8H-purin-8-one, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0130] In one embodiment, the compound of Formula I is Compound 342, which can be referred to as ((2R,3R,4S,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(2,2,2-trifluoroethyl)-7,8-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)acetate, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0131] In one embodiment, the compound of Formula I is Compound 80, which can be referred to as 2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(2,2,2-trifluoroethyl)-7,9-dihydro-1H-purine-6,8-dione or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate or a pharmaceutically acceptable hydrate thereof.

[0132] In one embodiment, the compound of Formula I is Compound 231, which can be referred to as 2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(2,2,2-trifluoroethyl)-7,9-dihydro-8H-purin-8-one, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0133] In one embodiment, the compound of Formula I is Compound 230, which can be referred to as ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(2,2,2-trifluoroethyl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)acetate, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0134] In one embodiment, the compound of Formula I is Compound 134, which can be referred to as 2-amino-7-(cyclopropylmethyl)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0135] In one embodiment, the compound of Formula I is Compound 335, which can be referred to as 2-amino-7-(cyclopropylmethyl)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0136] In one embodiment, the compound of Formula I is Compound 334, which can be referred to as ((2R,3R,4S,5R)-4-acetoxy-5-(2-amino-7-(cyclopropylmethyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)acetate, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0137] In one embodiment, the compound of Formula I is Compound 77, which can be referred to as 2-amino-7-(cyclopropylmethyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0138] In one embodiment, the compound of Formula I is Compound 223, which can be referred to as 2-amino-7-(cyclopropylmethyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0139] In one embodiment, the compound of Formula I is Compound 222, which can be referred to as ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(cyclopropylmethyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)acetate, or a pharmaceutically acceptable salt, a pharmaceutically acceptable solvate, or a pharmaceutically acceptable hydrate thereof.

[0140] In another embodiment the compound of formula I is selected from Table 1 and compared to Loxoribine.

[0141] Table 1. Compounds of Formula I

[0142]

[0143]

[0144] General Experiments

[0145] Compounds of formula I can be prepared by the following general methods.

[0146] In one approach (Scheme 1), the synthetic agent can be derived from a guanosine nucleoside analog II, wherein R 1 It can be H, OH, F, and R 2 is H or F and R 3 is OH. C-8 of the guanine base can be brominated under the conditions described by Holmes et al., JACS, 1964, p. 1242 and Sheu et al., JACS, 1995, p. 6439 to give the 8-bromo-guanosine derivative III. The oxygen can be S-reacted to the bromine of III by the alkoxide of benzyl alcohol as described by Holmes et al., JACS, 1964, p. 1242 and Sheu et al., JACS, 1995, p. 6439. N Ar is introduced at C-8 by substitution to give 8-benzyloxy-guanosine derivative IV. Before debenzylation of the oxygen at C-8, the nitrogen at N-1 needs to be protected to achieve selective alkylation of N-7. Broom et al., JOC, 1969, p. 1025 describe the amination of guanosine N-1, which essentially acts as a protecting group. Thus, intermediate IV can be exposed to hydroxylamine-O-sulfonic acid under alkaline conditions to give an N-1 aminoguanosine derivative V. The benzyl group can then be removed from the C-8 oxygen under a number of deetherification reaction conditions, preferably by catalytic hydrogenation with palladium metal, to give the cyclic urea intermediate VI. N-7 alkylation of intermediate VI can be carried out under alkaline conditions with R 4 -Lv is completed to obtain N-7 alkyl intermediate VII. 4 It is C 1 -C 8 Alkyl group and Lv is defined as a leaving group such as a halogen atom, OSO 2 CH 3 (mesylate), OSO 2 CF 3 (triflate), or OSO 2 Ar wherein Ar is 4-methylphenyl (tosylate). The final step of the synthesis is as described in U.S. Pat. No. 5,093,318, by forming a diazonium salt with sodium nitrite under aqueous acidic conditions to achieve N-1 deamination of VII to give the desired compound of formula I wherein R 5 For OH.

[0147] Solution 1

[0148]

[0149] Another approach (Scheme 2) starts with intermediate IV (described above), where the amide oxygen can be converted to the 6-chloropurine intermediate VIII, typically with phosphorus oxychloride. This can then be catalytically hydrogenated or with a boron trihalide such as BCl 3 Selective removal of the benzyl ether at C-8 affords intermediate IX. N-7 alkylation of intermediate IX can be accomplished with R 4 -Lv is completed to obtain the N-7 alkyl compound of formula I. 4 and Lv are defined in Method A.

[0150] R 5 The compound of formula I wherein R 5 H, OH or OCH 3 In order to obtain other compounds of formula I wherein R 5 Compounds of formula I where R is H can be subjected to a hydrodehalogenation reaction. This conversion can generally be carried out under hydrogenation conditions of activated zinc in Pd or acetic acid. The C-6 chlorine can be replaced with a hydroxyl group in an alkaline aqueous solution or under acidic conditions. The chlorine can also be replaced with a methoxide anion to produce a compound wherein R 5 OCH 3 A compound of formula I.

[0151] Solution 2

[0152]

[0153] Yet another method (Scheme 3) starts with intermediate IV (described above), where the amide oxygen can be converted to the 6-thiopurine intermediate X, typically using phosphorus pentasulfide, Lawesson's reagent, or similar products. The sulfur group can be reduced with Raney nickel to give intermediate XI. This can then be catalytically hydrogenated or with a boron trihalide such as BCl 3 Selective removal of the benzyl ether at C-8 affords intermediate XII. N-7 alkylation of intermediate XII can be accomplished with R 4 -Lv is completed to obtain the N-7 alkyl compound of formula I. 4 and Lv are as defined above.

[0154] Solution 3

[0155]

[0156] In another approach (Scheme 4), 6-chloro-2,4-diaminopyrimidine [156-83-2] can be halogenated with bromine, N-bromosuccinimide, or N-iodosuccinimide to afford 5-halo-6-chloro-2,4-diaminopyrimidine XIII. Exposure of intermediate XIII to an alkyl isocyanate can form the corresponding urea XIV. Intramolecular cyclization of intermediate XIV can be accomplished under reaction conditions using an appropriate Pd catalyst and a phosphine ligand, or by heating with copper(I) iodide with an amine base in a polar aprotic solvent to provide 2-amino-6-chloro-7-alkyl-7,9-dihydro-8H-purin-8-one of formula XV. The 6-chloro group can then be hydrodehalogenated with hydrogen and Pd or Pt metal to form XVI, where R 5 H. In order to form R 5 The 6,8-dioxopurine XVII with OH can be prepared by exposing XV to aqueous HCl or aqueous NaOH. The 6-chloro group of XV can also be replaced with a methoxide anion to give XVIII, where R 5 OCH 3 , or by substitution with sodium hydrosulfide to obtain XIX, where R 5 is SH. Typically, the purine intermediates XV-XIX can then be exposed to a sugar derivative XX under various nucleoside-forming reaction conditions, followed by hydroxyl deprotection to afford the 9-β-furan-purine nucleoside analogs of Formula I. For a comprehensive review of synthetic conditions for nucleoside formation, see Romeo et al., Chem. Rev. 2010, 110, pp. 3337-3370.

[0157] Solution 4

[0158]

[0159] Another method for preparing 2-amino-6-chloro-7-alkyl-7,9-dihydro-8H-purin-8-ones of formula XV is outlined below (Scheme 5).

[0160] Solution 5

[0161]

[0162] Starting from the common intermediate XIII, XXI can be generated from tert-butyl carbamate under the reaction conditions of appropriate palladium catalyst and phosphine ligand. The carbamate intermediate can then undergo intramolecular cyclization under thermal conditions to form the purine of formula XV.

[0163] Alternatively, intermediate XXI can be prepared by a similar two-step process by forming XXII from XIII and tert-butyl carbamate under the reaction conditions of an appropriate Pd catalyst and a phosphine ligand (Scheme 6). 4-Lv alkylates the carbamate nitrogen to generate XXI.

[0164] Solution 6

[0165]

[0166] 2-Amino-6-chloro-7-alkyl-7,9-dihydro-8H-purin-8-ones of formula XV can also be synthesized in two steps via XXI as shown below (Scheme 7).

[0167] Solution 7

[0168]

[0169] Exposure of XXI to trifluoroacetic acid can afford pyrimidine XXIII, which can be further converted to XV using carbonyldiimidazole or bis(trichloromethyl) carbonate or bis(4-nitrophenyl) carbonate or other suitable urea forming reagents.

[0170] An alternative method for preparing intermediate XVII is schematically depicted below (Scheme 8). The chlorine of pyrimidine XIII can be directly displaced with the sodium salt of benzyl alcohol to form XXIV. Under appropriate reaction conditions with Pd catalyst, phosphine ligand and alkylamine, 6-(benzyloxy)-N-(2-(4-nitrophenyl)-1 ... 5 -alkyl substituted 2,4,5-pyrimidine XXV. XXVI can be generated from carbonyldiimidazole or bis(trichloromethyl) carbonate or bis(4-nitrophenyl) carbonate or other suitable urea forming reagents. Purine intermediate XXVI can be reacted under catalytic hydrogenation or other ether cleavage conditions to form XVII.

[0171] Solution 8

[0172]

[0173] A second method for preparing 2-amino-6-benzyloxy-7-alkyl-7,9-dihydro-8H-purin-8-ones of formula XXVI is outlined below (Scheme 9).

[0174] Solution 9

[0175]

[0176] Using appropriate reaction conditions with a Pd catalyst, a phosphine ligand, and a tert-butyl alkyl carbamate, intermediate XXVII can be formed. The carbamate intermediate can then undergo intramolecular cyclization under thermal conditions to form a purine of formula XXVI.

[0177] Alternatively, exposure of XXVII to trifluoroacetic acid can provide pyrimidine XXV, which can subsequently be converted to XXVI using carbonyldiimidazole or bis(trichloromethyl) carbonate or bis(4-nitrophenyl) carbonate or other suitable urea-forming reagents.

[0178] XXVI and XX can be used to generate XXVII (Scheme 10) by glycosylation of the N-9 of the purine base using the conditions described above (Scheme 4). The benzyl ether can be removed sequentially by catalytic hydrogenation or with a boron trihalide reagent to give compounds of formula I, wherein R 5 For OH.

[0179] Solution 10

[0180]

[0181] Another possible route to the synthesis of purine intermediate XXVI involves exposure of intermediate XXIV to an alkyl isocyanate which can form the corresponding urea XXVIII (Scheme 11). Intramolecular cyclization of intermediate XXVIII can be accomplished under reaction conditions using an appropriate Pd catalyst and a phosphine ligand, or by heating with copper(I) iodide and an amine base in a polar aprotic solvent to provide 2-amino-6-benzyloxy-7-alkyl-7,9-dihydro-8H-purin-8-ones of formula XXVI.

[0182] Solution 11

[0183]

[0184] In another approach (Scheme 12), the chlorine atom of the symmetrical 4,6-dichloropyrimidine-2,5-diamine [55583-59-0] can be replaced with a benzylamine such as 4-methoxybenzylamine to form XXIX. Exposure of the intermediate XXIX to phosgene or a phosgene-like product such as carbonyldiimidazole can form the corresponding cyclic urea XXX. The primary amino group can then be protected to form XXXI, wherein P is a protecting group such as an acyl or carbamoyl group. The intermediate XXXI can be hydrodehalogenated with hydrogen and Pd or Pt metal or activated Zn under acidic conditions to form XXXII. Alternatively, the chlorine atom of XXXI can be replaced with an appropriate alcohol, preferably benzyl alcohol, to form XXXIII. The N-protected-N-9-benzyl-7,9-dihydro-8H-purin-8-ones XXXI, XXXII and XXXIII can be further treated with R at N-7 under basic conditions. 4 Alkylation of -Lv afforded N-7 alkyl compounds XXXIV, XXXV and XXXVI, respectively. 4and Lv are defined above. After N-7 alkylation, N-9 of XXXIV and XXXV can be deprotected under appropriate conditions. Depending on the protecting group used on the primary amine, the group can also be removed at the same time. For example, under acidic conditions such as trifluoroacetic acid combined with trifluoromethanesulfonic acid, intermediates XV and XVI can be formed from XXXIV and XXXV, respectively. Under similar acidic conditions, XVII can be formed from XXXVI. In a similar manner, intermediates XVIII and XIX can be synthesized using the general method described in Scheme 12. The purine intermediates XV-XIX can then be exposed to a sugar derivative XX under various nucleoside forming reaction conditions, and then the hydroxyl group is deprotected if a 9-β-furanopurine purine nucleoside analog of formula I is desired. Similarly, the primary amino groups of intermediates XV-XVII can be protected to form XXXVII-XLI, wherein P is a protecting group, such as an acyl group or a carbamoyl group. The purine intermediates XXXVII-XLI can then be exposed to a sugar derivative XX under a variety of nucleoside-forming reaction conditions, followed by deprotection to afford the 9-β-furano-purine nucleoside analogs of Formula I.

[0185] Solution 12

[0186]

[0187] Therapeutic uses of TLR7 agonists

[0188] TLR7 activation of innate immunity is primarily mediated by plasmacytoid dendritic cells (pDCs). These cells are the major physiological producers of type I interferon, up to 1000 times more than any other cell type. Therefore, activation of TLR7 is an important "gatekeeper" for the overall induction of innate immune responses. Compared with other TLRs, TLR7 has significant advantages as a therapeutic target. For example, it can be activated by small molecules that can be taken orally. Unlike several other TLRs, systemic activation of TLR7 avoids stimulating excessive production of TNF.

[0189] Direct or indirect administration of TLR7 agonists involves multiple antitumor mechanisms, including: the production of cytokines and chemokines with direct antitumor activity; activation of natural killer (NK) cells, the main effector cells of the innate immune system that control cancer, which are then able to lyse tumor cells by antibody-dependent (antibody-dependent cellular cytotoxicity or ADCC) and independent mechanisms; activation of T cells through antigen presentation and reversal of T cell exhaustion through direct cellular interaction with pDCs and production of cytokines and chemokines by pDCs, all of which lead to increased T cell-mediated attack on tumor cells; increased proliferation and maturation of normal B cells and their precursors, which can enhance endogenous production of antibodies with antitumor activity; direct activity of abnormal B cells can be induced by activation of TLR7 on these cells, thereby inducing apoptosis and hypersensitivity to chemotherapy.

[0190] In one embodiment, the TLR7 agonist compounds of the present invention can be used alone, or in combination with other additional therapeutic agents and treatment procedures, to treat or prevent cancer or infection or infectious disease in a subject in need of such treatment or prevention.

[0191] In one embodiment, the TLR7 agonist compounds of the present invention can be used alone or in combination with a tumor vaccine.

[0192] In one embodiment, the TLR7 agonist compounds of the present invention may be used alone or in combination with chemotherapeutic agents.

[0193] In one embodiment, the TLR7 agonist compounds of the invention may be used alone or in combination with radiation therapy.

[0194] In one embodiment, the TLR7 agonist compounds of the present invention can be used alone or in combination with targeted therapy. Examples of targeted therapy include: hormone therapy, signal transduction inhibitors (e.g., EGFR inhibitors, such as cetuximab (Erbitux) and erlotinib (Tarceva)); HER2 inhibitors (e.g., trastuzumab (Herceptin) and pertuzumab (Perjeta)); BCR-ABL inhibitors (e.g., imatinib (Gleevec) and dasatinib (Sprycel)); ALK inhibitors (e.g., crizotinib (Xalkori) and seletinib (c eritinib (Zykadia); BRAF inhibitors (such as vemurafenib (Zelboraf) and dabrafenib (Tafinlar)), gene expression modulators, apoptosis inducers (e.g., bortezomib (Velcade) and carfilzomib (Kyprolis)), angiogenesis inhibitors (e.g., bevacizumab (Avastin) and ramucirumab (Cyramza), toxin-attached monoclonal antibodies (e.g., brentuximab vedotin (Adcetris) and ado-trastuzumab emtansine (Kadcyla)).

[0195] In one embodiment, the TLR7 agonist compounds of the present invention can be used in combination with anticancer therapeutic agents, or immunomodulatory drugs such as immunomodulatory receptor inhibitors, or antibodies or antigen-binding fragments thereof that specifically bind to the receptor.

[0196] In one embodiment, the TLR7 agonist compound of the present invention can be used in combination with an immune checkpoint inhibitor, an OX40 agonist, a 4-1BB agonist, an ICOS agonist, a GITR agonist, or an IL2-receptor agonist.

[0197] In one embodiment, the TLR7 agonist compounds of the present invention can be used in combination with an inhibitor or antagonist of PD-1, PD-L1, CTLA4, TIM3, LAG3, SIRPα, CD47, VISTA, BTLA or TIGIT.

[0198] In one embodiment, the TLR7 agonist compounds of the invention may be used in combination with a therapeutic antibody having anti-tumor activity mediated at least in part by ADCC.

[0199] In one embodiment, the TLR7 agonist compounds of the present invention can be used in combination with therapeutic antibodies having anti-tumor activity mediated at least in part by ADCC, including rituximab, trastuzumab, and alemtuzumab.

[0200] In one embodiment of the invention, the TLR7 agonist compounds of the invention are combined with anti-OX40 antibodies (including MOXR0916 and GSK3174998) or other pathway agonists.

[0201] In one embodiment of the present invention, the TLR7 agonist compounds of the present invention are combined with anti-4-1BB antibodies (including urelumab, utomilumab) or other pathway agonists.

[0202] In one embodiment of the invention, the TLR7 agonist compounds of the invention are combined with an anti-ICOS antibody or other pathway agonist.

[0203] In one embodiment of the invention, the TLR7 agonist compounds of the invention are combined with an anti-GITR antibody or other pathway agonist.

[0204] In one embodiment of the invention, the TLR7 agonist compounds of the invention are combined with an IL-2-receptor or other pathway agonist.

[0205] In one embodiment of the invention, the TLR7 agonist compounds of the invention are combined with anti-PD1 or anti-PDL1 antibodies, including nivlumab (Opdivo), pembrolizumab (Keytruda), atezoluzimab (Tecentriq), durvalumab (Imfinzi) or avelumab (Bavencio).

[0206] In one embodiment of the invention, the TLR7 agonist compounds of the invention are combined with a CTLA-4 / CD80-CD86 antagonist, including ipilimumab (Yervoy).

[0207] In one embodiment of the invention, the TLR7 agonist compounds of the invention are combined with Tim-3 pathway antagonists, including MBG453 and TSR-022.

[0208] In one embodiment of the invention, the TLR7 agonist compounds of the invention are combined with LAG-3 pathway antagonists, including BMS-986016, GSK2831781 and IMP321.

[0209] In one embodiment of the present invention, the TLR7 agonist compound of the present invention is combined with an anti-SIRPα antibody.

[0210] In one embodiment of the present invention, the TLR7 agonist compounds of the present invention are combined with an anti-CD47 antibody.

[0211] In one embodiment of the invention, the TLR7 agonist compounds of the invention are combined with a Vista pathway antagonist.

[0212] In one embodiment of the invention, the TLR7 agonist compounds of the invention are combined with a BTLA pathway antagonist.

[0213] In one embodiment of the invention, the TLR7 agonist compounds of the invention are combined with a TIGIT pathway antagonist.

[0214] In another embodiment, the TLR7 agonist compounds of the present invention increase the activity of immune cells. The increase in the activity of immune cells can be detected using any method known in the art. In one embodiment, the increase in the activity of immune cells can be detected by measuring the proliferation of immune cells. For example, the increase in T cell activity can be detected by measuring the proliferation of T cells or signal transduction events (such as tyrosine phosphorylation of immune receptors or downstream kinases, transmitting signals to transcription regulators). In other embodiments, the increase in the activity of immune cells can be detected by measuring the cytotoxicity of CTL or NK cells on specific target cells or IFNγ cytokine responses, which are related to the stimulation of anti-tumor immunity. In other embodiments, the increase in the activity of immune cells can be detected by measuring T cell activation in vitro in a sample derived from an object.

[0215] Other agents that are beneficial to improve cytolytic T cell responses can be used in combination with the TLR7 agonist compounds of the present invention. These include, but are not limited to: B7 costimulatory molecules, interleukin-2 (e.g., NKTR-214), interferon-γ, GM-CSF, CTLA-4 antagonists, OX-40 / OX-40 ligands, CD40 / CD40 ligands, sargramostim, levamisole, vaccinia virus, BCG (BCG), liposomes, alum, Freund's complete or incomplete adjuvant, detoxified endotoxin, mineral oil, surfactants (such as lecithin), polyols, polyanions, peptides, and oil or hydrocarbon emulsions.

[0216] In one embodiment of the invention, the TLR7 agonist compounds of the invention are combined with one or more antiemetics, including but not limited to: casopitant (GlaxoSmithKline), netupitant (MGI-Helsinn) and other NK-1 receptor antagonists, palonosetron (sold as Aloxi by MGI Pharma), aprepitant (sold as Emend by Merck and Co.; Rahway, NJ), diphenhydramine (sold as New York, NY), hydroxyzine (sold by Pfizer as New York, NY), metoclopramide (sold by AH Robbins as Richmond, Virginia), lorazepam (marketed by Wyeth as Sales; Madison, New Jersey), alprazolam (Pfizer as New York, NY), haloperidol (sold by Ortho-McNeil as Sales; Raritan, New Jersey), Droperidol Dronabinol (sold by Solvay Pharmaceuticals, Inc. as Marietta, Georgia), dexamethasone (sold by Merck as Sold by Pfizer; Rahway, New Jersey), methylprednisolone ( New York, NY), chlorpromazine (sold by GlaxoSmithKline as Research Triangle Park, N.C.), granisetron (sold by Hoffmann-La Roche Inc. as Nutley, NJ), ondansetron (GSK as Research Triangle Park, NC), dolasetron (sold by Sanofi-Aventis as New York, NY), toprosetron (sold by Novartis as Sales; East Hanover, NJ).

[0217] Other side effects of cancer treatment include red blood cell and white blood cell deficiencies. Therefore, in one embodiment of the invention, TLR7 agonist compounds are combined with agents that treat or prevent such deficiencies, including filgrastim, PEG-filgrastim, erythropoietin, epoetin alpha, and darbepoetin alpha.

[0218] In another embodiment, the present invention relates to a composition comprising one or more TLR7 agonist compounds of the present invention and a pharmaceutically acceptable carrier or diluent. Such a composition may further include one or more other therapeutically active ingredients such as agonist antibodies or antigen binding fragments thereof, or TNF receptor proteins, immunoglobulin-like proteins, cytokine receptors, integrins, signaling lymphocyte activation molecules (SLAM proteins), OX40, 4-1BB (CD137), ICOS (CD278), GITR, IL2R beta (CD122) and / or IL2Rγ soluble fusions.

[0219] The present invention comprises a composition comprising a TLR7 agonist compound of the present invention and one or more antibodies targeting PD-1 / PD-L1 interaction or CTLA-4 / CD80-CD86 interaction. Non-limiting examples of such antibodies include: pembrolizumab, nivolumab, avelumab, REGN2810, MEDI-0680, PDR-001, SHR-1210, BGB-A317, PF-06801591, TSR-042, atezoluzumab, durvalumab, BMS-936559, ipilimumab and tremelimumab.

[0220] Compositions for inducing a T cell immune response that preferentially stimulate a cytolytic T cell response over an antibody response are preferred, although those that stimulate both types of responses may also be used.

[0221] In another embodiment, the composition comprising one or more TLR7 agonist compounds may further comprise one or more other therapeutically active ingredients, which are immune checkpoint inhibitors, OX40 agonists, 4-1BB agonists, ICOS agonists, GITR agonists or IL2-receptor agonists.

[0222] In another embodiment, the composition comprising one or more TLR7 agonist compounds may further comprise one or more other therapeutically active ingredients that are inhibitors or antagonists of PD-1, PD-L1, CTLA4, TIM3, LAG3, SIRPα, CD47, VISTA, BTLA or TIGIT.

[0223] In another embodiment, a composition comprising one or more TLR7 agonist compounds may further comprise one or more other therapeutically active ingredients that are therapeutic antibodies having anti-tumor activity mediated at least in part by ADCC.

[0224] In another embodiment, the composition comprising one or more TLR7 agonist compounds may further comprise one or more other therapeutically active ingredients, which are therapeutic antibodies having anti-tumor activity mediated at least in part by ADCC, including rituximab, trastuzumab, and alemtuzumab.

[0225] The present invention also provides methods of treating or preventing cancer or infection or infectious diseases in subjects, including human subjects, in need of such treatment or prevention using TLR7 agonist compounds disclosed herein. In one embodiment of the invention, such subjects suffer from cancer or precancerous conditions. In another embodiment of the invention, such subjects suffer from infection or infectious diseases.

[0226] In another embodiment, the present invention also relates to a method for treating or preventing cancer in a human subject, comprising administering to the subject an effective amount of one or more TLR7 agonist compounds of the present invention, optionally further combined with a therapeutic agent or treatment procedure; and to a method for treating an infection or infectious disease in a human subject, comprising administering to the subject an effective amount of one or more TLR7 agonist compounds of the present invention, optionally further combined with a therapeutic agent or treatment procedure.

[0227] In another embodiment, the present invention also relates to a method for increasing the activity of immune cells, which comprises administering to a subject in need thereof an effective amount of one or more TLR7 agonist compounds of the present invention to treat or prevent cancer; treat infection or infectious diseases; use as a vaccine adjuvant; or increase immune cell activation.

[0228] In one embodiment, the present invention provides a method of using a TLR7 agonist compound of the present invention to treat a subject, wherein the subject has cancer or a precancerous condition. In one embodiment, the cancer is, for example, osteosarcoma, rhabdomyosarcoma, neuroblastoma, renal cancer, leukemia, renal metastatic cell carcinoma, bladder cancer, Wilms' carcinoma, ovarian cancer, pancreatic cancer, breast cancer, prostate cancer, bone cancer, lung cancer (e.g., non-small cell lung cancer), gastric cancer, colorectal cancer, cervical cancer, synovial sarcoma, head and neck cancer, squamous cell carcinoma, multiple myeloma, renal cell carcinoma, retinoblastoma, hepatoblastoma, hepatocellular carcinoma, melanoma In one embodiment of the invention, the cancer is a metastatic cancer, such as a variant of the above.

[0229] In one embodiment, the present invention provides a method of using a TLR7 agonist compound of the present invention to treat a subject, wherein the subject suffers from a viral infection. In one embodiment, the viral infection is selected from the following viral infections: human immunodeficiency virus (HIV), hepatitis virus (A, B or C), herpes virus (e.g., VZV, HSV-1, HAV-6, HSV-II and CMV, Epstein-Barr virus), adenovirus, influenza virus, flavivirus, echovirus, rhinovirus, coxsackievirus, coronavirus, respiratory syncytial virus, mumps virus, rotavirus, measles virus, rubella virus, parvovirus, vaccinia virus, HTLV virus, dengue virus, papillomavirus, molluscum virus, poliovirus, rabies virus, JC virus or arboviral encephalitis virus.

[0230] In one embodiment, the invention provides methods of using the TLR7 agonist compounds of the invention to treat a subject, wherein the subject has a bacterial infection. In one embodiment, the bacterial infection is selected from the group consisting of Chlamydia, rickettsial bacteria, mycobacteria, staphylococci, streptococci, pneumonococci, meningococci and gonococci, klebsiella, proteus, serratia, pseudomonas, Legionella, Corynebacterium diphtheriae, Salmonella, bacilli, Vibrio cholerae, Clostridium tetan, Clostridium botulinum, Bacillus anthricis, Yersinia pestis, pestis), Mycobacterium leprae, Mycobacterium lepromatosis, and Borriella.

[0231] In one embodiment, the invention provides methods of using the TLR7 agonist compounds of the invention to treat a subject, wherein the subject has a fungal infection. In one embodiment, the fungal infection is selected from the group consisting of Candida (albicans, krusei, glabrata, tropicalis, etc.), Cryptococcus neoformans, Aspergillus (fumigatus, niger, etc.), Genus Mucorales (mucor, absidia, rhizopus), Sporothrix schenkii, Blastomyces dermatitidis, Paracoccidioides brasiliensis, Coccidioides immitis, and Histoplasma capsulatum.

[0232] In one embodiment, the present invention provides a method of using a TLR7 agonist compound of the present invention to treat a subject, wherein the subject suffers from a parasitic infection. In one embodiment, the parasitic infection is selected from the following parasitic infections: Entamoeba histolytica, Balantidium coli, Naegleria fowleri, Acanthamoeba, Giardia lamblia, Cryptosporidium, Pneumocystis carinii, Plasmodium vivax, Babesia microti, Trypanosoma brucei, Trypanosoma cruzi, Leishmania donovani, Toxoplasma gondii and Nippostrongylus brasiliensis.

[0233] The present invention includes a method for treating or preventing cancer in a subject, comprising administering an effective amount of a TLR7 agonist compound of the present invention and one or more antibodies targeting the PD-1 / PD-L1 or CTLA-4 / CD80-CD86 interaction of the subject. In one embodiment of the present invention, the TLR7 agonist compound of the present invention is combined with an anti-PD1 or anti-PDL1 antibody.

[0234] The present invention includes a method for treating or preventing cancer in a subject, comprising administering an effective amount of a TLR7 agonist compound of the present invention in combination with an immune checkpoint inhibitor, an OX40 agonist, a 4-1BB agonist, an ICOS agonist, a GITR agonist, or an IL2-receptor agonist.

[0235] The present invention includes a method for treating or preventing cancer in a subject, comprising administering an effective amount of a TLR7 agonist compound of the present invention in combination with an inhibitor or antagonist of PD-1, PD-L1, CTLA4, TIM3, LAG3, SIRPα, CD47, VISTA, BTLA or TIGIT.

[0236] The present invention encompasses methods of treating or preventing cancer in a subject comprising administering an effective amount of a TLR7 agonist compound of the present invention in combination with a therapeutic antibody having anti-tumor activity mediated at least in part by ADCC.

[0237] The present invention includes a method for treating or preventing cancer in a subject, comprising administering an effective amount of a TLR7 agonist compound of the present invention in combination with a therapeutic antibody having anti-tumor activity mediated at least in part by ADCC, including rituximab, trastuzumab and alemtuzumab.

[0238] The invention encompasses methods of treating or preventing cancer in a subject comprising administering an effective amount of a TLR7 agonist compound of the invention in combination with an anti-OX40 antibody, including MOXR0916 and GSK3174998, or other pathway agonists.

[0239] The present invention includes methods for treating or preventing cancer in a subject, comprising administering an effective amount of a TLR7 agonist compound of the present invention in combination with an anti-4-1BB antibody, including urelumab, utomilumab, or other pathway agonists.

[0240] The present invention includes methods of treating or preventing cancer in a subject comprising administering an effective amount of a TLR7 agonist compound of the present invention in combination with an anti-ICOS antibody or other pathway agonist.

[0241] The present invention includes methods of treating or preventing cancer in a subject comprising administering an effective amount of a TLR7 agonist compound of the present invention in combination with an anti-GITR antibody or other pathway agonist.

[0242] The present invention includes methods of treating or preventing cancer in a subject comprising administering an effective amount of a TLR7 agonist compound of the present invention in combination with an IL-2-receptor or other pathway agonist.

[0243] The present invention includes a method of treating or preventing cancer in a subject, comprising administering an effective amount of a TLR7 agonist compound of the present invention in combination with an anti-PD1 or anti-PDL1 antibody, including nivlumab (Opdivo), pembrolizumab (Keytruda), atezoluzimab (Tecentriq), durvalumab (Imfinzi), or avelumab (Bavencio).

[0244] The present invention encompasses methods of treating or preventing cancer in a subject comprising administering an effective amount of a TLR7 agonist compound of the present invention in combination with a CTLA-4 / CD80-CD86 antagonist, including ipilimumab (Yervoy).

[0245] The present invention encompasses methods of treating or preventing cancer in a subject comprising administering an effective amount of a TLR7 agonist compound of the present invention in combination with a Tim-3 pathway antagonist, including MBG453 and TSR-022.

[0246] The present invention includes methods of treating or preventing cancer in a subject comprising administering an effective amount of a TLR7 agonist compound of the present invention in combination with a LAG-3 pathway antagonist (including BMS-986016, GSK2831781, and IMP321).

[0247] The present invention includes a method for treating or preventing cancer in a subject, comprising administering an effective amount of a TLR7 agonist compound of the present invention in combination with an anti-SIRPα antibody.

[0248] The present invention includes a method of treating or preventing cancer in a subject, comprising administering an effective amount of a TLR7 agonist compound of the present invention in combination with an anti-CD47 antibody.

[0249] The present invention includes methods of treating or preventing cancer in a subject comprising administering an effective amount of a TLR7 agonist compound of the present invention in combination with a Vista pathway antagonist.

[0250] The present invention encompasses methods of treating or preventing cancer in a subject comprising administering an effective amount of a TLR7 agonist compound of the present invention in combination with a BTLA pathway antagonist.

[0251] The present invention includes methods of treating or preventing cancer in a subject comprising administering an effective amount of a TLR7 agonist compound of the present invention in combination with a TIGIT pathway antagonist.

[0252] Pharmaceutical compositions and administration

[0253] The present invention also provides a pharmaceutical composition comprising: (i) a therapeutically effective amount of at least one compound of Formula I, or a stereoisomer, tautomer or pharmaceutically acceptable salt thereof; (ii) in combination with a pharmaceutically acceptable carrier, diluent or excipient. Pharmaceutical compositions comprising a pharmaceutically acceptable carrier, diluent, or excipient and other therapeutic agents are also part of the present invention.

[0254] As used herein, the term "drug" refers to a chemical substance intended for the relief, treatment, or prevention of a disease, which is a prescription drug or over-the-counter drug product approved by the U.S. Food and Drug Administration (or its similar agency outside the United States). Detailed information on the preparation and administration techniques of such compositions can be found in Remington: The Science and Practice of Pharmacy, 21st edition (Mack Publishing Co., Easton, Pennsylvania) and Nielloud and Marti-Mestres, Pharmaceutical Emulsions and Suspensions, 2nd edition (Marcel Dekker, Inc., New York). In order to prepare a pharmaceutical or sterile composition of a TLR7 agonist compound of the present invention, the compound is mixed with a pharmaceutically acceptable carrier or excipient. See, for example, Remington: The Science and Practice of Pharmacy, Mack Publishing Co., Easton, Pennsylvania (1984).

[0255] Formulations of therapeutic and diagnostic agents can be prepared by mixing with an acceptable carrier, excipient or stabilizer in the form of, for example, a lyophilized powder, slurry, aqueous solution or suspension (see, for example, Hardman et al. (2001) Goodman and Gilman's The Pharmacological Basis of Therapeutics, McGraw-Hill, New York, NY; Gennaro (2000) Remington: The Science and Practice of Pharmacy, Lippincott, Williams and Wilkins, New York, NY; Avis et al., eds. (1993) Pharmaceutical Dosage Forms: Parenteral Medications, Marcel Dekker, New York, NY; Lieberman et al., eds. (1990) Pharmaceutical Dosage Forms: Tablets, Marcel Dekker, New York, NY; Dekker, New York, NY; Lieberman et al., eds. (1990), Pharmaceutical Dosage Forms: Disperse Systems, Marcel Dekker, New York, NY; Weiner and Kotkoskie (2000), Excipient Toxicity and Safety, Marcel Dekker, Inc., New York, NY).

[0256] Toxicity and therapeutic efficacy of the compounds or compositions of the invention, administered alone or in combination with another therapeutic agent, can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, for example, by determining the LD 50 (lethal dose for 50% of the population) and ED 50 The dose ratio between toxic and therapeutic efficacy is the therapeutic index (LD 50 / ED 50 The data obtained from these cell culture assays and animal studies can be used in formulating a range of dosage for humans. The dosage of such compounds preferably lies within a range of circulating concentrations that include the ED with little or no toxicity. 50 The dosage may vary within this range depending on the dosage form and route of administration.

[0257] In yet another embodiment, the further therapeutic agent administered to a subject in combination with a TLR7 agonist compound of the invention is according to the Physician's Desk Reference 2003 (Thomson Healthcare; 57th Edition (November 1, 2002)).

[0258] Mode of administration can vary. For the purpose of this disclosure, the pharmaceutical composition can be administered in a variety of ways, including non-parenteral, parenteral, by inhalation spray, topical or rectal administration in a preparation containing a pharmaceutically acceptable carrier, adjuvant and excipient. "Non-parenteral administration" includes oral, buccal, sublingual, topical, transdermal, eye, ear, nose, rectal, cervical, lung, mucosal and vaginal routes. As used herein, the term parenteral includes but is not limited to subcutaneous, intravenous, intramuscular, intraarterial, intradermal, intrathecal and epidural injections performed by various infusion techniques. As used herein, intraarterial and intravenous injections include administration by catheter. It is also expected that the compounds of the present invention are administered in a tumor (directly into a tumor mass) or around a tumor (around a tumor mass). The term oral as used herein includes but is not limited to oral ingestion or delivery by sublingual or buccal routes. Oral administration includes liquid beverages, energy bars and pill preparations.

[0259] The pharmaceutical composition can be in any form suitable for the intended method of administration. When used for oral administration, for example, tablets, lozenges, lozenges, aqueous or oily suspensions, dispersible powders or granules, emulsions, hard or soft capsules, syrups or elixirs can be prepared. Compositions for oral use can be prepared according to any method known to pharmaceutical composition manufacturers, and the composition can include one or more agents, including sweeteners, flavoring agents, coloring agents and preservatives to provide a palatable preparation. Tablets containing pharmaceutical compounds mixed with non-toxic pharmaceutically acceptable excipients suitable for making tablets are acceptable. These excipients can be, for example, inert diluents, such as calcium carbonate or sodium carbonate, lactose, calcium phosphate or sodium phosphate; granulating agents and disintegrants, such as corn starch or alginic acid; adhesives, such as starch, gelatin or gum arabic; and lubricants, such as magnesium stearate, stearic acid or talc. Tablets may be uncoated or may be coated by known techniques including enteric coating, colonic coating or microencapsulation to delay disintegration and absorption in the gastrointestinal tract and / or to provide a sustained action over a longer period of time. For example, a time delay material such as glyceryl monostearate or glyceryl distearate, alone or with a wax, may be employed.

[0260] The present invention provides containers (e.g., plastic or glass vials, e.g., with caps or chromatographic columns, hollow needles or syringe barrels) containing one or more compounds of the present invention or pharmaceutical compositions thereof. The present invention also provides injection devices containing one or more compounds of the present invention or pharmaceutical compositions thereof. An injection device is a device for introducing a substance into a patient's body by a parenteral route, e.g., intramuscularly, subcutaneously or intravenously. For example, an injection device can be a syringe (e.g., pre-filled with a pharmaceutical composition, such as an automatic syringe), e.g., it includes a cylinder or syringe for containing a fluid to be injected, a needle for puncturing the skin and / or a blood vessel to inject a fluid (e.g., one or more compounds of the present invention or pharmaceutical compositions thereof); and a plunger for pushing the fluid out of the cylinder and through the needle hole. In one embodiment of the present invention, an injection device containing one or more compounds of the present invention or pharmaceutical compositions thereof is an intravenous (IV) injection device. Such a device includes one or more compounds in a cannula or cannula / needle, which can be attached to a catheter, which can be attached to a catheter containing a fluid (e.g., saline; or a syringe containing NaCl, sodium lactate, KCl, CaCl 2 and optionally containing a bag or reservoir of lactated Ringer's solution of glucose), the fluid is introduced into the patient through a cannula or cannula / needle. In one embodiment of the invention, once the cannula needle and cannula are inserted into the vein of the subject and the cannula needle is removed from the inserted cannula, one or more compounds of the present invention or their pharmaceutical compositions can be introduced into the device. The IV device can, for example, be inserted into a peripheral vein (e.g., in the hand or arm); into the superior vena cava or inferior vena cava, or into the right atrium of the heart (e.g., a central vein); or into the subclavian vein, internal jugular vein, or femoral vein, for example, advancing toward the heart until reaching the superior vena cava or right atrium (e.g., a central venous line). In one embodiment of the invention, the injection device is an automatic syringe; a jet injector or an external infusion pump. The jet injector uses a high-pressure narrow liquid jet to penetrate the epidermis and introduce one or more compounds of the present invention or their pharmaceutical compositions into the patient. An external infusion pump is a medical device that delivers a pharmaceutical composition to a patient in a controlled amount. The external infusion pump can be powered electrically or mechanically. Different pumps operate in different ways, for example, a syringe pump holds fluid in a reservoir in a syringe, and a movable piston controls the delivery of the liquid, an elastomeric pump holds fluid in a stretchable balloon reservoir, and the pressure of the elastic wall of the balloon drives the delivery of the fluid. In a peristaltic pump, a set of rollers squeeze down on a length of flexible tubing, pushing the fluid forward. In a multichannel pump, fluid can be delivered from multiple reservoirs at multiple rates.

[0261] The compounds and pharmaceutical compositions disclosed herein can also be administered with a needle-free subcutaneous injection device; for example, a needle-free subcutaneous injection device disclosed in U.S. Pat. Nos. 6,620,135; 6,096,002; 5,399,163; 5,383,851; 5,312,335; 5,064,413; 4,941,880; 4,790,824 or 4,596,556. Such a needle-free device containing a pharmaceutical composition is also part of the present invention. The pharmaceutical compositions disclosed herein can also be administered by infusion. Examples of well-known implants and modules for administering pharmaceutical compositions include those disclosed in the following documents: U.S. Pat. No. 4,487,603 discloses an implantable microinfusion pump for dispensing drugs at a controlled rate; U.S. Pat. No. 4,447,233 discloses a drug infusion pump for delivering drugs at a precise infusion rate; U.S. Pat. No. 4,447,224 discloses a variable flow implantable infusion device for continuous drug delivery; U.S. Pat. No. 4,439,196 discloses an osmotic drug delivery system with multiple chambers. Many other such implants, delivery systems, and modules are well known to those skilled in the art, and those implants, delivery systems, and modules comprising the pharmaceutical compositions of the present invention are also within the scope of the present invention.

[0262] Alternatively, the TLR7 agonist compounds of the present invention can be administered locally rather than systemically, for example by injecting the compound into the tumor. In addition, the TLR7 agonist compounds of the present invention can be administered in a targeted drug delivery system, for example in a liposome coated with a tissue-specific antibody, the liposome targeting, for example, a tumor characterized by immunopathology. The liposomes will be targeted and selectively absorbed by the corresponding tissue. Such methods and liposomes are part of the present invention.

[0263] When the disclosed compound or its salt is named or depicted by structure, it should be understood that the compound or its salt, including its solvate (particularly hydrate), can exist in crystalline form, amorphous form or a mixture thereof. The compound or its salt or its solvate (particularly hydrate) can also exhibit polymorphism (i.e., the ability to appear in different crystalline forms). These different crystalline forms are generally referred to as "polymorphs". It should be understood that when named or depicted by structure, the disclosed compound or its solvate (particularly hydrate) also includes all its polymorphs. Polymorphs have the same chemical composition, but differ in other descriptive aspects of stacking, geometric arrangement and crystalline solid state. Polymorphs can have different physical properties, such as density, shape, hardness, stability and solubility properties. Polymorphs generally exhibit different melting points, IR spectra and X-ray powder diffraction patterns, which can be used for identification. It will be understood by those of ordinary skill in the art that different polymorphs can be produced, for example, by changing or adjusting the conditions used during the crystallization or recrystallization of the compound.

[0264] For the solvates of the crystalline form of the compounds of the present invention or their salts, those skilled in the art will appreciate that pharmaceutically acceptable solvates can be formed in which solvent molecules are incorporated into the crystal lattice during the crystallization process. Solvates may involve non-aqueous solvents such as ethanol, isopropanol, dimethyl sulfoxide, acetic acid, ethanolamine and ethyl acetate, or they may involve water as a solvent incorporated into the crystal lattice. Solvates in which water is a solvent incorporated into the crystal lattice are commonly referred to as "hydrates". Hydrates include stoichiometric hydrates as well as compositions containing variable amounts of water. The present invention includes all of these solvates.

[0265] Due to its potential use in medicine, the salt of the compound of the present invention is preferably pharmaceutically acceptable. Suitable pharmaceutically acceptable salts include those described by P. Heinrich Stahl and Camille G. Wermuth in Handbook of Pharmaceutical Salts: Properties, Selection, and Use, 2nd edition (Wiley-VCH: 2011) and Remington's Pharmaceutical Sciences, 18th edition (Mack Publishing, Easton, Pennsylvania, 1990) and Remington: The Science and Practice of Pharmacy, 19th edition (Mack Publishing, Easton, Pennsylvania: 1995).

[0266] Typical pharmaceutically acceptable salts include, for example, alkali metal salts, alkaline earth metal salts, ammonium salts, water-soluble salts and water-insoluble salts, such as acetate, stilbenesulfonate (4,4-diaminostilbene-2,2-disulfonate), benzenesulfonate, benzoate, bicarbonate, bisulfate, bitartrate, borate, bromide, butyrate, calcium, calcium edetate, camphorsulfonate, carbonate, chloride, citrate, clavulariate, dihydrochloride, edetate, edisylate, propionate estolate, esylate, fumarate, glucoheptonate, gluconate, glutamate, glycolyl arsenate, hexafluorophosphate, hexylresorcinate, halamine, hydrobromide, hydrochloride, hydroxynaphthalene The pharmaceutically acceptable salts include formate, iodate, isothiosulfate, lactate, lactobionate, laurate, malate, maleate, mandelate, methanesulfonate, methylbromide, methylnitrate, methanesulfonate, mucate, naphthenate, nitrate, N-methylglucamine ammonium salt, 3-hydroxy-2-naphthoate, oleate, oxalate, palmitate, pamoate (1,1-methylene-bis-2,2-hydroxy-3-naphthoate, einbonate), pantothenate, phosphate / diphosphate, picrate, polygalacturonate, propionate, p-toluenesulfonate, salicylate, stearate, subacetate, succinate, sulfate, sulfosalicylate, suramate, tannate, tartrate, 8-chlorotheophylline salt (teoclate), toluenesulfonate, triethiodide, trifluoroacetate and valerate. Pharmaceutically acceptable salts may have more than one charged atom in the structure. In this case, the pharmaceutically acceptable salt may have multiple counterions.Thus, a pharmaceutically acceptable salt may have one or more charged atoms and / or one or more counterions.

[0267] Salts of the compounds of the invention can be prepared by any suitable method known in the art, including treating the free base with an inorganic acid such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like, or with an organic acid such as acetic acid, trifluoroacetic acid, maleic acid, succinic acid, mandelic acid, fumaric acid, malonic acid, formic acid, alginic acid, pyruvic acid, oxalic acid, glycolic acid, salicylic acid, a pyranosyl acid such as glucuronic acid or galacturonic acid, an alpha hydroxy acid such as citric acid or tartaric acid, an amino acid such as aspartic acid or glutamic acid, an aromatic acid such as benzoic acid or cinnamic acid, or a sulfonic acid such as p-toluenesulfonic acid or ethanesulfonic acid.

[0268] Pharmaceutically acceptable salts can be prepared with bases which provide a pharmaceutically acceptable cation, including alkali metal salts (especially sodium and potassium), alkaline earth metal salts (especially calcium and magnesium), aluminum and ammonium salts, zinc, and from physiologically acceptable organic bases such as diethylamine, isopropylamine, hydroxylamine, benzathine penicillin, phenethylamine, tromethamine (2-amino-2-(hydroxymethyl)propane-1,3-diol), morpholine, pyrolidine, piperidine, piperazine, picoline, dicyclohexylamine, N,N'-dibenzylethylenediamine, 2-hydroxyethylamine, tris(2-hydroxyethyl)amine, chloroprocaine, choline, deanol, imidazole, diethanolamine, ethylenediamine, meglumine (N-methylglucamine), procaine, dibenzylpiperidine, dehydroabietinamine, glucosamine, collidine, quinine, quinolones, terbutylamine, and basic amino acids such as lysine and arginine.

[0269] If a compound containing a basic amine or other basic functional group is isolated as a salt, the corresponding free base form of the compound may be prepared by any suitable method known in the art, including treating the salt with an inorganic or organic base, suitably an inorganic or organic base having a higher pKa than the free base form of the compound. Similarly, if a compound containing a phosphodiester, a thiophosphorothioate diester or other acidic functional group is isolated as a salt, the corresponding free acid form of the compound may be prepared by any suitable method known in the art, including treating the salt with an inorganic or organic acid, suitably an inorganic or organic acid having a lower pKa than the free acid form of the compound.

[0270] As described herein, the effective amount of a compound or a pharmaceutically acceptable salt, pharmaceutically acceptable solvate or pharmaceutically acceptable hydrate thereof for a particular patient may vary depending on a variety of factors, such as the disease being treated, the patient's overall health, the route and dosage of administration, and the severity of side effects.

[0271] "Pharmaceutically acceptable prodrugs" are compounds that can be converted to a specified compound or a pharmaceutically acceptable salt of such a compound under physiological conditions or by solvolysis before exhibiting its pharmacological action. Generally, the purpose of formulating prodrugs is to improve chemical stability, improve patient acceptance and compliance, improve bioavailability, prolong duration of action, improve organ selectivity, improve formulations (e.g., increase water solubility) and / or reduce side effects (e.g., toxicity). Prodrugs can be easily prepared from compounds of formula I using methods known in the art, such as those described in Burger's Medicinal Chemistry and Drug Chemistry, 1, 172-178, 949-982 (1995). See also Bertolini et al., J. Med. Chem. 1997, 40, 2011-2016; Shan et al., J. Pharm. Sci. 1997, 86(7), 765-767; Bagshawe, Drug Dev. Res. 1995, 34, 220-230; Bodor, Adv. Drug Res. 1984, 13, 224-331; Bundgaard, Design of Prodrugs (Elsevier Press, 1985); and Larsen, Design and Application of Prodrugs, Drug Design and Development (Krogsgaard-Larsen et al., eds., Harwood Academic Press, 1986). Publishers, 1991); Dear et al., J. Chromatogr. B, 748, 281-293 (2000); Spraul et al., J. Pharmaceutical & Biomedical Analysis, 10, 601-605 (1992); and Prox et al., Xenobiol., 3, 103-112 (1992).

[0272] Methods of co-administration with additional therapeutic agents are well known in the art (Hardman et al., eds. (2001) Goodman and Gilman's The Pharmacological Basis of Therapeutics, 10th ed., McGraw-Hill, New York, NY; Poole and Peterson, eds. (2001) Pharmacotherapeutics for Advanced Practice: A Practical Approach, Lippincott, Williams and Wilkins, Philadelphia, PA; Chabner and Longo, eds. (2001) Cancer Chemotherapy and Biotherapy, Lippincott, Williams and Wilkins, Philadelphia, PA). In general, co-administration or administration together refers to treating a subject with two or more agents, wherein the agents may be administered simultaneously or at different times. For example, these agents can be delivered to a single subject as separate administrations, which can be performed substantially at the same time or at different times, and can be performed by the same route or by different routes of administration. Such agents can be delivered to a single subject in the same manner of administration (e.g., the same preparation) so that they can be administered at the same time by the same route of administration.

[0273] Typically, each administration of a compound of the invention will comprise about 10 mg to about 2000 mg in a subject, for example, about 10 mg to about 50 mg, about 50 mg to about 100 mg, about 100 mg to about 250 mg, about 250 mg to about 500 mg, about 500 mg to about 1000 mg, about 1000 mg to about 2000 mg.

[0274] General approach

[0275] Unless otherwise stated in the examples, all synthetic chemistry was performed in standard laboratory glassware. Commercial reagents were used as is. Microwave reactions were performed in Biotage's Initiator using instrument software to control heating time and pressure. LC / MS analysis was performed on an Agilent 1290infinity, quality: 6150SQD (ESI / APCI) or Agilent 1200 series, quality: 6130SQD (ESI / APCI); variable wavelength detector and Agilent 6130 single quadrupole mass spectrometer, alternating positive and negative ion scans using Chemistation software. Retention time was determined from the extracted 220nmUV chromatogram. HPLC was performed on a Waters 2695 system with a variable wavelength detector using Empower software. Retention time was determined from the extracted 210nm and 300nm UV chromatograms. The 400 MHz Bruker Avance 400 or 500 MHz Bruker Avance DRX-500 were used with Topspin software. 1 H NMR. For complex splitting patterns, the obvious splittings are listed. Analytical thin layer chromatography was performed on silica gel (Macherey-Nagel ALUGRAMXtra SIL G, 0.2 mm, UV254 indicator) and visualized under UV light. Silica gel chromatography was performed manually or using a Grace automatic chromatograph with gradient elution. Melting points were collected using a Büchi B-540 melting point apparatus.

[0276] Standard methods of molecular biology are described in Sambrook, Fritsch and Maniatis (2nd edition, 1982 & 1989, 3rd edition, 2001) Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY; Sambrook and Russell (2001) Molecular Cloning, 3rd edition, Cold Spring Harbor Press, Cold Spring Harbor, NY; Wu (1993) Recombinant DNA, Vol. 217, Academic Press, San Diego, California. Standard methods also appear in Ausbel et al. (2001) Current Protocols in Molecular Biology, John Wiley & Sons, Inc., New York, NY, which describes cloning and DNA mutagenesis of bacterial cells (Volume 1), cloning of mammalian cells and yeast (Volume 2), glycoconjugates and protein expression (Volume 3), and bioinformatics (Volume 4).

[0277] Standard methods for immune system histology are also described (see, e.g., Muller-Harmelink, ed. (1986) Human Thymus: Histopathology and Pathology. Springer Verlag, New York, NY; Hiatt et al. (2000) Color Atlas of Histology. Lippincott, Williams and Wilkins Publishers, Philadelphia, PA; Louis et al. (2002) Basic Histology: Text and Atlas. McGraw-Hill, New York, NY).

[0278] Software packages and databases are available for determining, for example, antigenic fragments, leader sequences, protein folding, functional domains, glycosylation sites, and sequence alignments (see, e.g., GenBank (Informax, Inc., Bethesda, MD); GCG Wisconsin Software Package (Accelrys Inc., San Diego, CA); (TimeLogic Corp., Crystal Bay, Nevada); Menne et al. (2000) Bioinformatics 16:741-742; Menne et al. (2000) Bioinformatics Applications Note 16:741-742; Wren et al. (2002) Comput. Methods Programs Biomed. 68:177-181; von Heijne (1983) Eur. J. Biochem. 133:17-21; von Heijne (1986) Nucleic Acids Res. 14:4683-4690). Example

[0279] Embodiment 1: 2-amino-7-(cyclopropylmethyl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 1

[0280]

[0281] Compound 1 was prepared according to the following multi-step process.

[0282]

[0283] Step 1: 2-Amino-8-bromo-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (2)

[0284] To a stirred solution of 2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (1) [27462-39-1] (15.0 g, 53 mmol) in 250 mL of water was slowly added aqueous bromine solution (4.5 mL, 1.5 equivalents) at room temperature, prepared according to the procedures of Zou et al. Can. J. Chem., 1987, p. 1436 and Robins et al. JOC, 1996, p. 9207. In a sealed round-bottom flask, the reaction mixture was stirred at room temperature overnight. Aqueous sodium thiosulfate solution was added to destroy excess bromine. The reaction mixture was filtered and the filtrate was washed with water and acetone. The solid was dried under vacuum to afford 15.4 g of the desired product, 2-amino-8-bromo-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (2) as an off-white solid in 80% yield.

[0285] Step 2: 2-Amino-8-(benzyloxy)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (3)

[0286] In a round bottom flask, sodium fragments (6.0 gm, 260.9 mmol) were added to 60 mL of benzyl alcohol. The mixture was stirred at room temperature for 0.5 h and then heated until it became a solution. A solution of 2-amino-8-bromo-9-((2R, 3R, 4R, 5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purine-6-one (2) (15.4 g, 42 mmol) in 60 mL of DMSO was added to the stirred solution obtained above. It was stirred for 10 h. Glacial acetic acid was added to the stirred reaction mixture to adjust to neutrality. The mixture was treated with ether. The ether layer was poured out and the remaining material was treated with acetone. The solid was filtered and washed with water. The crude product was recrystallized from ethanol-water (1:1) to give 11.0 g of 2-amino-8-(benzyloxy)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (3) as an off-white solid with a yield of 67%.

[0287] Step 3: 1,2-Diamino-8-(benzyloxy)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (4)

[0288] 2-Amino-8-(benzyloxy)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purine-6-one (3) (11.0 g, 28 mmol) was dissolved in 150 mL of 2N aqueous sodium hydroxide solution. Hydroxylamine-O-sulfonic acid (9.35 g, 82 mmol, 3 equiv.) was added. The reaction mixture was stirred at room temperature overnight and filtered. The solid was washed with acetone to obtain 5.8 g of white solid product 1,2-diamino-8-(benzyloxy)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purine-6-one (4) in 51% yield.

[0289] Step 4: 1,2-Diamino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (5)

[0290] 1,2-Diamino-8-(benzyloxy)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (4) (5.8 g, 14 mmol) was dissolved in 200 mL of ethanol and 200 mL of water in a hydrogenation flask by heating to 90°C. 1 g of 5% Pd / C was added. The reaction mixture was maintained under a hydrogen atmosphere at 40-50 psi in a Parr reactor overnight. The hydrogen was evacuated from the reactor and the catalyst was filtered off and washed with hot water. The filtrate was concentrated under reduced pressure to obtain a crude product, which was recrystallized from water to give 3.6 g of 1,2-diamino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (5) as a white solid in 81% yield.

[0291] Step 5: 1,2-Diamino-7-(cyclopropylmethyl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (6)

[0292] 1,2-Diamino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (5) (3.6 g, 11.4 mmol, 1.0 eq) was dissolved in 50 mL of anhydrous DMF. NaH (0.5 g, 12.6 mmol, 1.1 eq) was added to the stirred solution and further stirred for 1 hour. Cyclopropylmethyl bromide (1.70 g, 12.6 mmol, 1.1 eq) was added to the reaction mixture and stirring was continued at room temperature overnight. The reaction mixture was concentrated under reduced pressure. The residue was purified by flash chromatography on a silica gel column using dichloromethane-methanol (15:1) as eluent. 1,2-Diamino-7-(cyclopropylmethyl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (6) (2.5 g) was obtained as a white solid in 65% yield.

[0293] Step 6: 2-amino-7-(cyclopropylmethyl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 1

[0294] 1,2-Diamino-7-(cyclopropylmethyl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (6) (0.50 g, 1.4 mmol) was added to a flask containing 10 mL of DMF. Concentrated hydrochloric acid (1.0 mL) was added at 0°C. An aqueous solution of sodium nitrite (113 mg, 1.7 mmol) in 5 mL of water was added with stirring. After stirring for 30 minutes, sodium acetate (0.50 g, 6.3 mmol) was added. The reaction mixture was stirred for 25 minutes and concentrated under reduced pressure. The residue was purified by flash chromatography on a silica gel column using dichloromethane-methanol (10:1) as eluent to give 0.30 g of the product 2-amino-7-(cyclopropylmethyl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 1, as a white solid in 63% yield. HPLC purity 99.5%. 1 H NMR (DMSO-d 6,400MHz)δ11.03(s,1H),6.64(s,2H),5.69-5.77(m,2H),5.51(d,1H,J=4Hz),4.63(t,1H,J=8Hz),4.46-4.54(m, 1H),3.83-3.94(m,2H),3.61-3.73(m,3H),3.51-3.60(m,1H),1.12-1.25(m,1H),0.31-0.46(m,4H).MS(ESI),m / z 354.3[M+H] + .

[0295] Embodiment 2: 7-allyl-2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 2

[0296]

[0297] Compound 2 was prepared according to the following multi-step process.

[0298]

[0299] Step 1: 8-(Allyloxy)-2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (7)

[0300] Small pieces of sodium metal (0.4 g, 17.4 mmol) were added portionwise to stirred allyl alcohol (10 mL, 8.5 g, 146 mmol) and continued until all the sodium was completely dissolved and no more hydrogen was evolved. Anhydrous DMSO (10 mL) was added, followed by 2-amino-8-bromo-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (2) (Example 1) (1.0 g, 2.8 mmol). The reaction mixture was heated to 65°C with stirring and continued until TLC showed that the dichloromethane had consumed the 8-bromopurine starting material (dichloromethane-methanol: 2:1; R f=0.6). The solvent was concentrated under reduced pressure and the residue was treated with ether. The ether layer was decanted and the residue was purified by flash chromatography on a silica gel column using dichloromethane-methanol: 8:1 as eluent to give 190 mg of 8-(allyloxy)-2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (7) as an off-white solid in 21% yield.

[0301] Step 2: 7-allyl-2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 2

[0302] 8-(Allyloxy)-2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purine-6-one (7) (190 mg, 0.6 mmol) was dissolved in 15 mL of methanol and 150 mL of water. The reaction mixture was heated to reflux for 5 h. The solvent was concentrated under reduced pressure and the residue was purified by flash chromatography on a silica gel column using dichloromethane-methanol: 10:1 as eluent to give 134 mg of 7-allyl-2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, compound 2, as an off-white foam in 70.5% yield;

[0303] 1 H NMR (DMSO-d 6 ,400MHz)δ5.86-5.95(m,1H),5.67-5.74(m,2H),5.50(d,1H,J=3.2Hz),5.02-5.12(m,2H),4.60-4. 63(m,1H),4.41-4.50(m,3H),3.85-3.92(m,2H),3.64-3.69(m,1H),3.53-3.58(m,1H),MS(ESI),m / z 340.2

[0304] [M+H] + .

[0305] Embodiment 3: (2R,3S,4R,5R)-2-(acetoxymethyl)-5-(2-amino-7-(cyclopropylmethyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetate, Compound 3

[0306]

[0307] Compound 3 was prepared according to the following multi-step process.

[0308]

[0309] Step 1: (2R,3S,4R,5R)-2-(Acetoxymethyl)-5-(2-amino-8-(benzyloxy)-6-oxo-1,6-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetate (8)

[0310] A solution of 2-amino-8-(benzyloxy)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purine-6-one (3) (16.0 g, 41.1 mmol) in anhydrous pyridine (250 mL) was treated with acetic anhydride (15.5 mL, 164.4 mmol, 4.0 equiv) and a catalytic amount of DMAP (50 mg, 0.41 mmol, 0.01 equiv). The reaction mixture was stirred at room temperature overnight. After completion of the reaction monitored by TLC, the reaction mixture was diluted with ethyl acetate (300 mL) and poured into 500 mL of water. The layers were separated and the aqueous layer was extracted twice with ethyl acetate. The combined organic layers were washed with saturated saline solution, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography using dichloromethane-methanol (20:1) as the eluent to give 10 g of (2R,3S,4R,5R)-2-(acetoxymethyl)-5-(2-amino-8-(benzyloxy)-6-oxo-1,6-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetic acid diester (8) as a white foam in a 47.2% yield; R f =0.30 (dichloromethane-methanol=18:1).

[0311] Step 2: (2R,3S,4R,5R)-2-(Acetoxymethyl)-5-(2-amino-6-chloro-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetate (9)

[0312] In an oven-dried flask, (2R,3S,4R,5R)-2-(acetoxymethyl)-5-(2-amino-8-(benzyloxy)-6-oxo-1,6-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetic acid diester (8) (10 g, 19.4 mmol), benzyltriethylammonium chloride (8.8 g, 38.8 mmol, 2.0 equiv) and N,N-dimethylaniline (2.7 mL, 21.3 mmol, 1.1 equiv) were dissolved in 300 mL of anhydrous MeCN. Phosphorus oxychloride (9.0 mL, 97 mmol, 5.0 equiv) was then added with stirring at room temperature. The reaction mixture was stirred at room temperature for 1 h or TLC showed the disappearance of the starting material (8). At this time, the reaction mixture was moved to a preheated oil bath at 90 °C and heated for 3 h. After the reaction was completed as monitored by TLC, the reaction mixture was concentrated in vacuo. The obtained residue was dissolved in ethyl acetate (200 mL) and poured into 200 mL of saturated sodium bicarbonate solution. The aqueous layer was extracted with ethyl acetate, and the combined organic layers were washed with saturated saline solution, then dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The obtained residue was purified by column chromatography using dichloromethane-methanol (30:1) as eluent to obtain 1.8 g of the product (2R, 3S, 4R, 5R)-2-(acetoxymethyl)-5-(2-amino-6-chloro-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetic acid diester (9) as a white foam with a yield of 22%. f =0.60 (dichloromethane-methanol=18:1)

[0313] Step 3: (2R,3S,4R,5R)-2-(Acetoxymethyl)-5-(2-amino-6-chloro-7-(cyclopropylmethyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetate (10)

[0314] (2R,3S,4R,5R)-2-(acetoxymethyl)-5-(2-amino-6-chloro-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetic acid diester (9) (1.4 g, 3.2 mmol, 1.0 eq.) was dissolved in 50 mL of anhydrous DMF. 2 CO 3To 4-nitro-1-yl pyridine-2 ... The resulting residue was purified by column chromatography using dichloromethane-methanol (50:1) as eluent to give 1.18 g of the product (2R,3S,4R,5R)-2-(acetoxymethyl)-5-(2-amino-6-chloro-7-(cyclopropylmethyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetic acid diester (10) as a white foam in 75% yield. f =0.70 (dichloromethane-methanol=30:1)

[0315] Step 4: (2R,3S,4R,5R)-2-(acetoxymethyl)-5-(2-amino-7-(cyclopropylmethyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetate, Compound 3

[0316] (2R,3S,4R,5R)-2-(acetoxymethyl)-5-(2-amino-6-chloro-7-(cyclopropylmethyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetic acid diester (10) (1.0 g, 2.0 mmol) was dissolved in a mixture of anhydrous methanol (50 mL) and tetrahydrofuran (10 mL). 10% Pd / C (120 mg) was added, and the mixture was stirred under H 2 The mixture was stirred at room temperature under an atmosphere of (50 Psi) for 5 hours and 2 days. After completion of the reaction monitored by TLC, the catalyst was removed by filtration through a celite pad. The solvent was evaporated and the crude product was purified by flash chromatography on a silica gel column using dichloromethane-methanol (50:1) as eluent to provide 650 mg of (2R,3S,4R,5R)-2-(acetoxymethyl)-5-(2-amino-7-(cyclopropylmethyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetic acid diester, compound 3, in 70% yield, 98.2% HPLC purity as a white solid. f =0.20 (dichloromethane-methanol=30:1). 1 H NMR (CDCl 3,400MHz)δ7.87(s,1H),6.41–6.46(m,1H),5.85(d,1H,J=6.0Hz),5.48(t,1H,J=4.8Hz),4.83(s,2H),4.50–4.56(m,2H),4.36–4.44(m ,1H),3.64–3.69(m,1H),2.17(s,3H),2.03(s,3H),2.06(s,3H),1.08–1.19(m,1H),0.55–0.65(m,2H),0.35–0.41(m,2H); MS(ESI),m / z 464.2[M+H] + .

[0317] Embodiment 4: 2-amino-7-(cyclopropylmethyl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, Compound 4

[0318]

[0319] Compound 4 was prepared from compound 3 according to the following steps.

[0320]

[0321] (2R,3S,4R,5R)-2-(acetoxymethyl)-5-(2-amino-7-(cyclopropylmethyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetic acid diester, compound 3 (400 mg, 0.86 mmol) was dissolved in NH 3 -MeOH (20 mL). The mixture was stirred at room temperature overnight and then concentrated under reduced pressure. The residue was purified on a silica gel column to give 240 mg of 2-amino-7-(cyclopropylmethyl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, compound 4, as a white solid, 82% yield, HPLC purity 97.9%; R f =0.30 (dichloromethane-methanol=10:1). 1 H NMR (DMSO-d 6,400MHz)δ8.14(s,1H),6.34(s,2H),5.72(d,1H,J=4.8Hz),5.61–5.67(m,1H),5.57(d,1H,J=4.0Hz),4.61–4.66(m,1H),4.57 (t,1H,J=5.6Hz),3.91–3.99(m,2H),3.55–3.75(m,4H),1.10–1.20(m,1H),0.45–0.53(m,2H),0.32–0.40(m,2H); MS(ESI),m / z 338.4[M+H] + ,360.4[M+Na] + .

[0322] Embodiment 5: 2-Amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 5

[0323]

[0324] Compound 5 was prepared using a modified method for the synthesis of compound 1 according to the following steps.

[0325]

[0326] Step 1: 1,2-Diamino-8-(benzyloxy)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (4)

[0327] To a stirred solution of 2-amino-8-(benzyloxy)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (3) (5.1 g, 13 mmol) in 100 mL of anhydrous DMF at 0°C was added NaH (0.7 g, 16.9 mmol, 1.3 eq.). The reaction mixture was stirred for 30 min and O-(diphenylphosphinyl)hydroxylamine (4.5 g, 19.5 mmol, 1.5 eq.) was added. The reaction mixture was stirred at room temperature until completion as monitored by TLC (dichloromethane-methanol: 3:1). The precipitate was filtered and dried under vacuum to give 3.7 g of 1,2-diamino-8-(benzyloxy)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (4) as a white solid in 70% yield.

[0328] Step 2: 1,2-Diamino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (5)

[0329] 1,2-Diamino-8-(benzyloxy)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (4) (3.7 g, 9.1 mmol) was dissolved in 500 mL of ethanol and 500 mL of water in a hydrogenation flask by heating to 90°C. 0.8 g of 5% Pd / C was added. The reaction mixture was maintained under a hydrogen atmosphere at 40-50 psi in a Parr reactor overnight. The hydrogen was evacuated from the reactor and the catalyst was filtered off and washed with hot water. The filtrate was concentrated under reduced pressure to obtain a crude product, which was recrystallized from water to give 2.1 g of 1,2-diamino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (5) as a white solid in 72% yield.

[0330] Step 3: 1,2-Diamino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (11)

[0331] 1,2-Diamino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (5) (850 mg, 2.7 mmol, 1.0 eq.) was dissolved in 30 mL of anhydrous DMF. 2 CO 3 (410 mg, 3.8 mmol, 1.4 eq.) was added to the stirred solution and it was further stirred for 30 minutes. 3-Bromo-1-propyne (453 mg, 4.8 mmol, 1.8 eq.) was added to the reaction mixture and it was stirred overnight at room temperature. The reaction mixture was concentrated under reduced pressure. The residue was taken up in methanol and purified by flash chromatography on a silica gel column using dichloromethane-methanol (20:1) as eluent to give 610 mg of 1,2-diamino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (11) as a white solid in 74% yield.

[0332] Step 4: 2-Amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 5

[0333] 1,2-Diamino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (11) (610 mg, 1.7 mmol) was added to a flask containing 10 mL of DMF. Concentrated hydrochloric acid (0.65 mL) was added at 0°C. An aqueous solution of sodium nitrite (132 mg, 2.04 mmol, 1.2 equiv) in 3 mL of water was added with stirring. After stirring at 0°C for 30 minutes, the reaction mixture was concentrated under reduced pressure. The residue was purified by flash chromatography on a silica gel column using dichloromethane-methanol (10:1) as eluent to give 408 mg of 2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 5, as a white solid in 71% yield;

[0334] 1 H NMR (DMSO-d 6 ,400MHz)δ11.33(s,1H),6.78(br,2H),5.73–5.76(m,2H),5.48–5.47(d,1H,J=3.2Hz), 4.62–4.63(m,2H),4.50(s,1H),3.9(s,2H),3.30–3.65(m,2H),3.25(s,1H).MS(ESI)m / z 338.1(M+H) + ,360.1[M+Na] + .

[0335] The synthesis of compounds 6-8, 10-19 and 21-23 was completed using the same method as described for compound 1 or 5. Compounds 9 and 20 were initially prepared by simultaneous hydrolysis of the nitrile group under acidic conditions in the final N-1-deamination step. Compounds 10 and 21 can also be prepared from compounds 9 and 20, respectively, by esterification.

[0336] Embodiment 6:2-amino-7-(but-2-yn-1-yl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 6

[0337]

[0338] Off-white solid: 1 H NMR (DMSO-d 6 ,400MHz)δ:7.02(s,2H),5.82-5.83(d,1H,J=4.0Hz),5.66–5.68(d,1H,J=8.0Hz),5.46-5.47(d,1H,J=4.0H z),4.66(t,1H),4.57(t,1H,J=5.6Hz),4.56(m,1H),3.9(m,2H),3.11–3.37(m,2H),1.75(s,3H).MS(ESI)m / z 352.2(M+H) + ,374.1[M+Na] + .

[0339] Embodiment 7: 2-Amino-7-((E)-but-2-en-1-yl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 7

[0340]

[0341] Off-white solid: MS (ESI) m / z 354.2 (M+H) + ,376.1[M+Na] + .

[0342] Embodiment 8: 2-Amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-((E)-4-hydroxybut-2-en-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 8

[0343]

[0344] Off-white solid: 1 H NMR (DMSO-d 6,400MHz)δ6.71(s,2H),5.75(d,1H,J=4.8Hz),5.66–5.73(m,2H),5.46(m,1H),4.74(t,1H,J=5.6Hz),4.62(t,1H,J=5 .6Hz),4.41–4.48(m,1H),4.40–4.41(m,2H),3.80–3.98(m,4H),3.51–3.70(m,2H),3.17(d,1H,J=5.2Hz).MS(ESI)m / z 370.1(M+H) + ,392.1[M+Na] + .

[0345] Embodiment 9: (E)-4-(2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)but-2-enoic acid, Compound 9

[0346]

[0347] Off-white solid: 1 H NMR (DMSO-d 6 ,400MHz)δ11.15(s,1H),6.64–7.08(m,3H),5.59–5.69(m,1H),5.49(d,1H,J= 3.2Hz),4.48–4.68(m,3H),3.82–4.01(m,2H),3.49–3.74(m,2H).MS(ESI)m / z 384.1(M+H) + ,422.0[M+K] + .

[0348] Embodiment 10: (E)-4-(2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)but-2-enoic acid methyl ester, Compound 10

[0349]

[0350] Off-white solid: MS (ESI) m / z 398.1 (M+H) + ,420.1[M+Na] + .

[0351] Embodiment 11:2-Amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4-hydroxybut-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 11

[0352]

[0353] Off-white solid: MS (ESI) m / z 368.1 (M+H) + ,390.1[M+Na] + .

[0354] Embodiment 12: 2-(2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)acetate, Compound 12

[0355]

[0356] Off-white solid: MS (ESI) m / z 372.1 (M+H) + .

[0357] Embodiment 13: 2-Amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(2,2,2-trifluoroethyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 13

[0358]

[0359] Off-white solid: 1 H NMR (DMSO-d 6 ,400MHz) δ11.09(s,1H),6.86(s,2H),5.78(d,1H,J=4Hz),5.54(d,1H,J=4Hz),5.48(d,1H,J= 4Hz),4.55-4.67(m,4H),3.90-3.92(m,2H),3.64-3.69(m,1H),3.54-3.60(m,1H).MS(ESI)m / z 382.1(M+H) + ,404.2[M+Na] + .

[0360] Embodiment 14:2-Amino-7-(2,2-difluoroethyl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 14

[0361]

[0362] Off-white solid: 1 H NMR (DMSO-d 6 ,400MHz)δ11.09(s,1H),6.67(s,2H),6.14-6.44(m,1H),5.74(d,1H,J=4Hz),5.57(d,1H,J=8Hz),5.48(d,1H,J=4Hz),4 .61(d,1H,J=4Hz),4.53(s,1H),4.18-4.26(m,2H),3.88-3.93(m,2H),3.64-3.69(m,1H),3.53-3.59(m,1H).MS(ESI)m / z 386.0[M+Na] + .

[0363] Embodiment 15: 2-Amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-methyl-7,9-dihydro-1H-purine-6,8-dione, Compound 15

[0364]

[0365] Off-white solid: 1 H NMR (DMSO-d 6 ,400MHz)δ11.14(s,1H),6.79(s,2H),5.74-5.78(m,2H),5.51(d,1H,J=4Hz),4.63(t,1H,J=8Hz),4 .48-4.52(m,1H),3.85-3.92(m,2H),3.63-3.69(m,1H),3.51-3.57(m,1H),3.36(s,3H).MS(ESI)m / z 314.1(M+H) + ,336.0[M+Na] + .

[0366] Embodiment 16: 2-Amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-ethyl-7,9-dihydro-1H-purine-6,8-dione, Compound 16

[0367]

[0368] Off-white solid: 1 H NMR (DMSO-d 6 ,400MHz)δ11.01(s,1H),6.61(s,2H),5.72-5.76(m,2H),5.51(d,1H,J=4Hz),4.63(t,1H,J=8Hz),4.47 -4.49(m,1H),3.81-3.91(m,4H),3.64-3.69(m,1H),3.52-3.58(m,1H),1.20(t,3H,J=8Hz).MS(ESI)m / z 328.1(M+H) + .

[0369] Embodiment 17: 2-Amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-propyl-7,9-dihydro-1H-purine-6,8-dione, Compound 17

[0370]

[0371] Off-white solid: 1 H NMR (DMSO-d 6 ,400MHz)δ10.95(s,1H),6.58(s,2H),5.71-5.74(m,2H),5.51(d,1H,J=4Hz),4.63(t,1H,J=8Hz),4.47-4.49(m,1H),3.84- 3.92(m,2H),3.76(t,2H,J=8Hz),3.64-3.69(m,1H),3.52-3.58(m,1H),1.60-1.69(m,2H),0.83(t,3H,J=8Hz).MS(ESI)m / z 342.2(M+H) + ,364.1[M+Na] + .

[0372] Embodiment 18: 2-Amino-7-butyl-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 18

[0373]

[0374] Tan solid: 1 H NMR (DMSO-d 6,400MHz)δ11.02(s,1H),6.58(s,2H),5.71-5.74(m,2H),5.51(d,1H,J=4Hz),4.63(t,1H,J=8Hz),4.47-4.49(m,1H),3.84-3.92(m,2 H),3.76(t,2H,J=8Hz),3.64-3.69(m,1H),3.52-3.58(m,1H),1.58-1.65(m,2H),1.21-1.30(m,2H),0.88(t,3H,J=8Hz).MS(ESI)m / z 356.1(M+H) + ,378.1[M+Na] + .

[0375] Embodiment 19: 2-Amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4-hydroxybutyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 19

[0376]

[0377] Off-white solid: MS (ESI) m / z 372.4 (M+H) + ,394.4[M+Na] + .

[0378] Embodiment 20: 4-(2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)butanoic acid, Compound 20

[0379]

[0380] Off-white solid: 1 H NMR (DMSO-d 6 ,400MHz)δ11.06(s,1H),6.69(bs,2H),5.50(d,1H J=3.2Hz),5.48–4.65(b,3H),4.49(dd,1H,J=3.0,1.8Hz),4.89(m,4H),3.85(ddd,1H,J=10.4, 6.4,4.8,1.6Hz),3.61(dd,1H,J=6.4,4.8Hz),2.21(t,2H,J=7.2Hz),1.88(m,2H).MS(ESI)m / z 386.1(M+H) + ,324.1[M+K]+ .

[0381] Embodiment 21: 4-(2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)butanoic acid methyl ester, Compound 21

[0382]

[0383] Off-white solid: MS (ESI) m / z 400.2 (M+H) + ,422.1[M+Na] + .

[0384] Embodiment 22: 2-Amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(2-methoxyethyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 22

[0385]

[0386] Off-white solid: MS (ESI) m / z 358.2 (M+H) + .

[0387] Embodiment 23: 2-Amino-7-(2-difluoroethyl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione hydrochloride, Compound 23

[0388]

[0389] Off-white solid: 1 H NMR (DMSO-d 6 ,400MHz)δ5.63(s,1H,J=4.0Hz),4.71(m,1H),4.13–4.21(m,4H),3.72–3.85(m,2H),3.25–3.33(m,2H).MS(ESI)m / z343.1(M+H) + .

[0390] Embodiment 24: (2R,3S,4R,5R)-2-(acetoxymethyl)-5-(2-amino-8-oxo-7-(prop-2-yn-yl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetic acid diester, Compound 24

[0391]

[0392] Compound 24 was prepared from (2R,3S,4R,5R)-2-(acetoxymethyl)-5-(2-amino-6-chloro-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetic acid diester (9) according to the following synthetic method.

[0393]

[0394] Step 1: (2R,3S,4R,5R)-2-(Acetoxymethyl)-5-(2-amino-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetic acid diester (12)

[0395] (2R,3S,4R,5R)-2-(acetoxymethyl)-5-(2-amino-6-chloro-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetic acid diester (9) (6.0 g, 13.6 mmol) was dissolved in a mixture of anhydrous methanol (100 mL) and tetrahydrofuran (10 mL). Catalyst Pd / C (150 mg, 10%) was added, and the mixture was heated at room temperature under H 2 The reaction mixture was stirred under an atmosphere of (50 Psi) for 5 h. The catalyst was filtered off through celite. The solvent was evaporated and the crude product was used in the next step without further purification.

[0396] Step 2: (2R,3S,4R,5R)-2-(acetoxymethyl)-5-(2-amino-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetate, Compound 24

[0397] (2R,3S,4R,5R)-2-(acetoxymethyl)-5-(2-amino-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetic acid diester (12) (13.6 mmol) was dissolved in 150 mL of anhydrous DMF. Potassium carbonate (2.8 g, 20.4 mmol, 1.5 eq) was added to the stirred solution and further stirred for 5 min. At this point, 3-bromopropyne (1.9 mg, 16.32 mmol, 1.2 eq) was added to the reaction mixture and stirred at 45 °C for 5 h. The mixture was concentrated under reduced pressure and the resulting residue was purified by column chromatography using dichloromethane-methanol (70:1) as eluent to afford 3.5 g of (2R,3S,4R,5R)-2-(acetoxymethyl)-5-(2-amino-8-oxo-7-(prop-2-yn-yl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetic acid diester, compound 24, as a white foam in 60% yield in two steps with an HPLC purity of 98%. f =0.50 (dichloromethane-methanol=30:1). 1 H NMR (CDCl 3 ,400MHz)δ8.01(s,1H),6.35–6.43(m,1H),5.83(d,1H,J=5.6Hz),6.43–6.51(m,1H),4.91(s,2H),4.59(t,1H,J=1.6 Hz),4.46–4.56(m,2H),4.36–4.45(m,1H),2.37(t,1H,J=2.4Hz),2.17(s,3H),2.07(s,3H),2.06(s,3H).MS(ESI)m / z 448.2[M+H] + ,470.2[M+Na] + .

[0398] Embodiment 25: 2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one, Compound 25

[0399]

[0400] Compound 25 was prepared from Compound 24 using the procedure outlined for the preparation of Compound 4 from Compound 3.

[0401] (2R,3S,4R,5R)-2-(acetoxymethyl)-5-(2-amino-8-oxo-7-(prop-2-yn-yl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diacetic acid diester, compound 24 (600 mg, 1.3 mmol) was dissolved in saturated NH 3 The mixture was stirred at room temperature overnight and then concentrated under reduced pressure. The residue was purified on a silica gel column to give 300 mg of 2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one, compound 25, as a white solid, 72% yield, HPLC purity 98.8%; R f =0.50 (dichloromethane-methanol=6:1). 1 H NMR (CDCl 3 ,400MHz)δ8.08(s,1H),6.44(s,2H),5.72(d,1H,J=4.8Hz),5.49–5.60(m,2H),4.46– 4.76(m,4H),3.92–4.03(m,2H),3.55–3.71(m,2H),3.41(t,1H,J=2.4Hz).MS(ESI)m / z 322.1(M+H) + ,344.1[M+Na] + .

[0402] Embodiment 26: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 26

[0403]

[0404] 2-Amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, compound 5, was synthesized using a general method as shown in the following synthetic scheme starting from 3'-deoxy-guanosine [3608-58-0] and its corresponding 3'-deoxy-8-bromoguanosine [847649-68-7] to prepare 2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, compound 26.

[0405]

[0406] Step 1: 2-Amino-8-bromo-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (12)

[0407] At 0°C, 3'-deoxyguanosine (2 g, 7.49 mmol, 1 eq) was reacted with H 2 To the 1H-HCl (20 mL) solution was added NBS (2.6 g, 14.98 mmol, 2 equiv.) and the reaction mixture was stirred at 0 °C for 1 h. The reaction was monitored by TLC. The reaction mixture was diluted with water (50 mL) and extracted with n-butanol (3×100 ml); extracted with ethyl acetate; the organic layer was washed with water (100 mL), brine (100 mL), and concentrated. The residue was triturated with ether, filtered, and dried under reduced pressure to give 1.7 g (65%) of 2-amino-8-bromo-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (12) as an off-white solid. 1 H NMR (400 MHz, DMSO-d 6 ): δ10.81(brs,1H),6.53(s,2H),5.62(d,J=3.2Hz,1H),5.54(s,1H),4.94(s,1H),4.80(s,1H),4.24– 4.18(m,1H),3.50(d,J=3.6Hz,2H),2.47–2.43(m,1H),1.91–1.86(m,1H).(ESI)m / z344.0,346.0(MH) - .

[0408] Step 2: 2-Amino-8-(benzyloxy)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (13)

[0409] Sodium metal (339 mg, 14.78 mmol, 3 eq) was dissolved in benzyl alcohol (7.9 g, 73.91 mmol, 15 eq) and heated to 65 °C until a clear solution was observed. The reaction mixture was then warmed to room temperature, and a solution of 2-amino-8-bromo-9-((2R, 3R, 5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (1.7 g, 4.92 mmol, 1 eq) in DMSO (8 mL) was added dropwise thereto at room temperature. The reaction mixture was then stirred at 80 °C for 5 h. The reaction was monitored by TLC. The reaction mixture was diluted with water (50 mL) and washed with diethyl ether (2×100 mL), and the aqueous layer was extracted with n-butanol (3×100 mL). The organic layer was washed with water (100 mL), brine (100 mL) and concentrated to give a crude product which was triturated with diethyl ether to afford 1.6 g (87%) of 2-amino-8-(benzyloxy)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (13) as an off-white solid. 1 H NMR (500 MHz, DMSO-d 6 ): δ11.65(brs,1H),7.48(d,J=7Hz,2H),7.42–7.30(m,3H),6.31(brs,2H),5.54(d,J=3.5Hz,1H),5.48(s,1H),5.39(d,,J= 4Hz,2H),5.31(brs,1H),4.75(s,1H),4.16–4.11(m,1H),3.45–3.43(m,2H),2.21–2.15(m,1H),1.85–1.80(m,1H).(ESI)m / z 374.1(M+H) + .

[0410] Step 3: 1,2-Diamino-8-(benzyloxy)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (14)

[0411] To a solution of 2-amino-8-(benzyloxy)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (1.6 g, 4.28 mmol, 1 eq) in DMF (20 mL) was added 60% NaH (2.5 mg, 5.14 mmol, 1.2 eq) at 0°C. After stirring for 30 min, O-(diphenylphosphoryl)hydroxylamine (1.59 g, 6.86 mmol, 1.6 eq) was added portionwise at the same temperature. The reaction mixture was stirred at room temperature for 2 h, and the precipitate formed was removed by filtration. The filtrate was diluted with water (50 mL) and extracted with n-butanol (3×100 mL). The organic layer was washed with water (100 mL), brine solution (100 mL) and concentrated to give a crude solid which was triturated with diethyl ether to afford 1.3 g (78%) of 1,2-diamino-8-(benzyloxy)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (14) as an off-white solid. 1 H NMR (400 MHz, DMSO-d 6 ): δ7.49(d,J=8Hz,2H),7.43–7.35(m,3H),6.97(s,2H),5.58–5.56(m,2H),5.40(s,2H),5.38(s,2H),4.79–4.77 (m,1H),4.72–4.71(m,1H),4.14–4.09(m,1H),3.39–3.35(m,2H),2.20–2.13(m,1H),1.80–1.75(m,1H).(ESI)m / z 389.1(M+H) + .

[0412] Step 4: 1,2-Diamino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (15)

[0413] In a Parr shaker vessel, 1,2-diamino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (1.3 g, 3.35 mmol, 1 eq) was added to a flask in EtOH:H 210% Pd / C (400 mg) was added to a solution of 4-nitropropene (2-nitropropene) (1:1; 60 mL). The reaction mixture was shaken with hydrogen (70 psi) for 2 h at room temperature. The progress of the reaction was monitored by TLC. After the starting material was consumed, the reaction mixture was filtered through a bed of celite and washed with ethanol. The combined filtrate was concentrated and the residue was triturated with diethyl ether to give 1.2 g (crude) of 1,2-diamino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (15) as an off-white solid. The product can be used as is or can be recrystallized from water. 1 H NMR (400 MHz, DMSO-d 6 ): δ10.64(s,1H),7.04(s,2H),5.50(d,J=4.4Hz,1H),5.41–5.36(m,1H),5.37(s,2H),4.82–4.80(m,1H),4 .73(t,J=5.6Hz,1H),4.13–4.12(m,1H),3.50–3.38(m,2H),2.40–2.32(m,1H),1.85–1.79(m,1H).(ESI)m / z 299.1(M+H) + .

[0414] Step 5: 1,2-Diamino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (16)

[0415] 1,2-Diamino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (15) (650 mg, 2.18 mmol, 1.0 eq.) was dissolved in 50 mL of anhydrous DMF. 2 CO 3(402 mg, 3.05 mmol, 1.4 eq) was added to the stirred solution and it was further stirred for 30 min. 3-Bromo-1-propyne (458 mg, 3.92 mmol, 1.8 eq) was added to the reaction mixture and it was stirred at room temperature overnight. The reaction mixture was concentrated under reduced pressure and the remaining residue was taken up in methanol and purified by flash chromatography on a silica gel column using dichloromethane-methanol (20:1) as eluent to give 505 mg of 1,2-diamino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (16) as a white solid in 69% yield. MS (ESI) m / z 337.1 (M+H) + .

[0416] Step 6: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 26

[0417] 1,2-Diamino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (16) (400 mg, 1.19 mmol) was added to a flask containing 10 mL of DMF. Concentrated hydrochloric acid (0.44 mL) was added at 0°C. An aqueous solution of sodium nitrite (98 mg, 0.98 mmol, 1.2 equiv) in 2 mL of water was added with stirring. The mixture was stirred at 0°C for 30 minutes. The reaction mixture was concentrated under reduced pressure. The residue was purified by flash chromatography on a silica gel column using dichloromethane-methanol (10:1) as eluent to give 240 mg of 2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 26, as a white solid in 67% yield; 1 H NMR (400 MHz, DMSO-d 6): δ10.98(s,1H),6.55(s,2H),5.51(d,J=3.6Hz,1H),5.39(d,J=4.4Hz,1H),4.81–4.77(m,1H),4.68(t,J=5.6Hz,1H),4 .56(d,J=2Hz,2H),4.16–4.12(m,1H),3.48–3.41(m,2H),3.22(s,1H),2.38–2.31(m,1H),1.85–1.79(m,1H).MS(ESI)m / z 322.1(M+H) + ,344.1[M+Na] + .

[0418] Embodiment 27: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 27

[0419]

[0420] 2-Amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, compound 5, was synthesized using a general method as shown in the following synthetic scheme starting from 3'-deoxy-(3'S)-fluoro-guanosine [123402-21-1] and its corresponding 3'-deoxy-(3'S)-fluoro-8-bromoguanosine [847649-50-7] to prepare 2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, compound 27.

[0421]

[0422] Step 1: 2-Amino-8-bromo-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (17)

[0423] In a fume hood, at room temperature, aqueous bromine solution (5.4 mL, 2 equivalents) was slowly added to a stirred solution of 3'-deoxy-(3'S)-fluoro-guanosine [123402-21-1] (15 g, 52.6 mmol) in 300 mL. The reaction mixture was stirred overnight at room temperature in a sealed round-bottom flask, or until completion was monitored by TLC. An aqueous sodium thiosulfate solution was added to destroy excess bromine. The reaction mixture was filtered, and the filtrate was washed with water and acetone. The solid was dried under vacuum to obtain 13 g of 2-amino-8-bromo-9-((2R, 3S, 4S, 5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purine-6-one (17) as an off-white solid in 68% yield.

[0424] Step 2: 2-Amino-8-(benzyloxy)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (18)

[0425] In a round-bottom flask, a small piece of sodium (1.2 g) was added to 28 mL of benzyl alcohol. The mixture was stirred at room temperature for 0.5 h and then heated to 65 ° C to become a solution. A solution of 2-amino-8-bromo-9-((2R, 3S, 4S, 5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (17) (7 g, 19.2 mmol) in 28 mL of DMSO was added to the stirred solution obtained above. The reaction mixture was stirred for 5 h until completion as monitored by TLC. Glacial acetic acid was added to the stirred reaction mixture to adjust the pH to 7. The mixture was poured into 1 L of ether under vigorous stirring. The upper ether layer was poured off and the remaining material was added to a large amount of acetone (800 mL) under stirring. The solid was filtered and the crude product was washed with water. The crude product was heated in a mixture of ethanol-water (1:1). The mixture was cooled to room temperature. The precipitate was filtered and dried under vacuum to give 4 g of 2-amino-8-(benzyloxy)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (18) as an off-white solid in 53% yield.

[0426] Step 3: 1,2-Diamino-8-(benzyloxy)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (19)

[0427] To a stirred solution of 2-amino-8-(benzyloxy)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purine-6-one (18) (2 g, 5.1 mmol) in 40 mL of anhydrous DMF was slowly added NaH (0.24 g, 6.1 mmol) at 0°C. The mixture was stirred for 30 minutes and O-(diphenylphosphinyl)hydroxylamine (1.9 g, 8.2 mmol) was added. The reaction mixture was stirred at room temperature until the starting material was consumed as indicated by TLC monitoring. The precipitate was filtered and dried under reduced pressure. The residue was purified by flash chromatography on a silica gel column using dichloromethane-methanol (10:1) as eluent to afford 1 g of 1,2-diamino-8-(benzyloxy)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (19) as a white solid in 50% yield.

[0428] Step 4: 1,2-Diamino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (20)

[0429] 1,2-Diamino-8-(benzyloxy)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (19) (1 g, 2.5 mmol) was dissolved in 1000 mL of ethanol and 1000 mL of water by heating to 90°C, and 10% Pd / C (0.2 g) was added. The reaction mixture was hydrogenated overnight under 1 atm of hydrogen atmosphere. The catalyst was filtered off and washed with hot water. The filtrate was concentrated under reduced pressure and the remaining crude solid was recrystallized from water to give 0.65 g of 1,2-diamino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (20) as a white solid in 84% yield.

[0430] Step 5: 1,2-Diamino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (21)

[0431] 1,2-Diamino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (20) (650 mg, 2 mmol, 1.0 eq.) was dissolved in 20 mL of anhydrous DMF. K 2 CO 3 (414 mg, 3 mmol, 1.5 eq.) and stirred for further 30 minutes. 3-Bromopropyne (476 mg, 4 mmol, 2 eq.) was added to the reaction mixture and stirred overnight at room temperature. The reaction mixture was concentrated under reduced pressure. The residue was taken up in methanol and purified by flash chromatography on a silica gel column using dichloromethane-methanol (15:1) as eluent to give 580 mg of 1,2-diamino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (21) as a white solid in 79% yield.

[0432] Step 6: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 27

[0433] 1,2-Diamino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (21) (580 mg, 1.63 mmol) was added to a flask containing 10 mL of DMF. Concentrated hydrochloric acid (0.6 mL) was added at 0°C. An aqueous solution of sodium nitrite (135 mg, 1.96 mmol, 1.2 equiv) in 5 mL of water was added with stirring. Stirring was continued at 0°C for 30 minutes, and then the reaction mixture was concentrated under reduced pressure. The residue was purified by flash chromatography on a silica gel column using dichloromethane-methanol (10:1) as eluent to give 465 mg of 2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 27, as a white solid in 83% yield; HPLC purity 96.5%; 1 HNMR (DMSO-d 6,400MHz)δ11.07(s,1H),6.81(s,2H),5.81(d,1H,J=4Hz),5.63(d,1H,J=8Hz),5.19–5.11(m,1 H),5.10-4.97(m,2H),4.60(s,2H),4.14–4.08(m,1H),3.59–3.52(m,2H),3.25(s,1H).ESI-MS m / z 340.1[M+H] + ,362.1[M+Na] + .

[0434] Embodiment 28: 2-Amino-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 28

[0435]

[0436] 2-Amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, compound 5, was synthesized using a general method as shown in the following synthetic scheme starting from 3'-deoxy-(3'R)-fluoro-guanosine [125291-15-8] to prepare 2-amino-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, compound 28.

[0437]

[0438] Step 1: 2-Amino-8-bromo-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (22)

[0439] In a fume hood, aqueous bromine solution (2.4 mL, 2 equiv.) was slowly added to a stirred solution of 3'-deoxy-(3'R)-fluoro-guanosine [125291-15-8] (6.7 g, 23 mmol) in 100 mL of water at room temperature. The reaction mixture was sealed in a round-bottom flask and stirred at room temperature overnight or until complete, as shown by TLC. Aqueous sodium thiosulfate solution was added to destroy excess bromine, the reaction mixture was filtered and the filtrate was washed with water and acetone. The solid was dried under vacuum to obtain 6.5 g of 2-amino-8-bromo-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purine-6-one (22) as an off-white solid in 76% yield.

[0440] Step 2: 2-Amino-8-(benzyloxy)-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (23)

[0441] In a round-bottom flask, a small piece of sodium (1.2 g, 3 eq.) was added to 25 mL of benzyl alcohol. The mixture was stirred at room temperature for 0.5 h and then heated to 65 °C until the sodium disappeared. A solution of 2-amino-8-bromo-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (22) (6.5 g, 17.8 mmol) in 30 mL of DMSO was added to the stirred sodium alcohol solution obtained above. It was stirred at 65 °C for 10 h until (22) was consumed as determined by TLC. Glacial acetic acid was added to the stirred reaction mixture to adjust the pH to 7. The mixture was poured into 1.5 L of ether with vigorous stirring. The solid was filtered and the crude product was washed with water. The crude product was heated in a mixture of ethanol-water (1:1) and then cooled to room temperature. The precipitate was filtered and dried under vacuum to give 3.8 g of 2-amino-8-(benzyloxy)-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (23) as an off-white solid in 54% yield.

[0442] Step 3: 1,2-Diamino-8-(benzyloxy)-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (24)

[0443] To a stirred solution of 2-amino-8-(benzyloxy)-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (23) (3.8 g, 9.7 mmol) in 80 mL of anhydrous DMF was slowly added NaH (0.46 g, 11.6 mmol) at 0°C. The reaction mixture was stirred for 30 minutes, and O-(diphenylphosphinyl)hydroxylamine (3.3 g, 14.5 mmol) was added and stirring was continued at room temperature until completion as determined by TLC. The precipitate was filtered and dried under reduced pressure. The residue was purified by flash chromatography on a silica gel column using dichloromethane-methanol (10:1) as eluent to afford 2 g of 1,2-diamino-8-(benzyloxy)-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (24) as a white solid in 51% yield.

[0444] Step 4: 1,2-Diamino-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (25)

[0445] 1,2-Diamino-8-(benzyloxy)-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purine-6-one (24) (2 g, 5 mmol) was dissolved in 1200 mL of ethanol and 1200 mL of water by heating to 90°C. 0.4 g of Pd / C catalyst (10%) was added. The reaction mixture was kept under 1 atmosphere of hydrogen overnight. The catalyst was filtered through diatomaceous earth and washed with hot water. The filtrate was concentrated under reduced pressure to give a solid, which was recrystallized from water to give 1.3 g of 1,2-diamino-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (25) as a white solid in 84%.

[0446] Step 5: 1,2-Diamino-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (26)

[0447] 1,2-Diamino-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (25) (1.3 g, 4.1 mmol, 1.0 equiv) was dissolved in 40 mL of anhydrous DMF. 2 CO 3 (854 mg, 6.1 mmol, 1.5 eq) was added to the stirred solution and it was further stirred for 30 min. 3-Bromopropyne (976 mg, 8.2 mmol, 2 eq) was added to the reaction mixture and it was stirred overnight at room temperature. The reaction mixture was concentrated under reduced pressure and the remaining residue was taken up in methanol and purified by flash chromatography on a silica gel column using dichloromethane-methanol (15:1) as eluent to give 1.2 g of 1,2-diamino-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (26) as a white solid in 82% yield.

[0448] Step 6: 2-Amino-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 28

[0449] 1,2-Diamino-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (26) (1.2 g, 3.39 mmol) was added to a flask containing 20 mL of DMF. Concentrated hydrochloric acid (1.2 mL) was added at 0°C. An aqueous solution of sodium nitrite (280 mg, 4.07 mmol, 1.2 equiv) in 10 mL of water was added with stirring. After stirring at 0°C for 30 minutes, the reaction mixture was concentrated under reduced pressure. The residue was purified by flash chromatography on a silica gel column using dichloromethane-methanol (10:1) as eluent to give 960 mg of 2-amino-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, compound 28, as a white solid in 83% yield; HPLC purity 96.3%; 1 H NMR (DMSO-d 6,400MHz)δ10.98(s,1H),6.60(s,2H),5.95(s,1H),5.35–5.37(m,2H),4.74–5.08(m ,2H),4.60(s,2H),4.00–4.08(m,1H),3.56–3.63(m,2H),3.24(t,1H,J=4Hz).ESI-MS m / z 340.1[M+H] + ,362.1[M+Na] + .

[0450] Embodiment 29: ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 29

[0451]

[0452] Compound 29 was prepared according to the following multi-step procedure.

[0453]

[0454] Step 1: ((2S,4R,5R)-4-Acetoxy-5-(2-amino-8-(benzyloxy)-6-oxo-1,6-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate (27)

[0455] A solution of 2-amino-8-(benzyloxy)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (13) (22 g, 58.9 mmol) in anhydrous MeCN (300 mL) containing triethylamine (40.8 mL) was treated with acetic anhydride (12.3 mL, 129.7 mmol, 2.2 equiv). The reaction mixture was stirred at room temperature overnight. The reaction mixture was diluted with dichloromethane (800 mL) and poured into 800 mL of water. The layers were separated and the aqueous layer was extracted twice with dichloromethane. The combined organic layers were washed with brine and washed with anhydrous Na 2 SO 4 The residue was dried and concentrated under reduced pressure. The obtained residue was purified by silica gel column chromatography using dichloromethane-methanol (50:1) as eluent to give 18.1 g of ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-(benzyloxy)-6-oxo-1,6-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate (28) as a yellow solid in 67% yield; R f=0.5 (dichloromethane-methanol=10:1).

[0456] Step 2: ((2S,4R,5R)-4-Acetoxy-5-(2-amino-6,8-dioxo-1,6,7,8-tetrahydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate (28)

[0457] In a dried flask, ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-(benzyloxy)-6-oxo-1,6-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate (27) (18.1 g, 39.6 mmol) was dissolved in 200 mL of dry MeCN. Phosphorus oxychloride (3.6 mL, 39.6 mmol, 1.0 equiv) was added and stirred at room temperature for 1 h. The reaction mixture was diluted with dichloromethane (800 mL) and poured into saturated aqueous sodium bicarbonate solution. The aqueous layer was extracted with dichloromethane. The combined organic layers were purified by anhydrous Na 2 SO 4 The resulting residue was dried and purified by column chromatography using dichloromethane-methanol (30:1) as eluent to afford 13 g of ((2S,4R,5R)-4-acetoxy-5-(2-amino-6,8-dioxo-1,6,7,8-tetrahydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate (28) as a white solid in 89% yield, R f =0.40 (dichloromethane-methanol=10:1).

[0458] Step 3: ((2S,4R,5R)-4-Acetoxy-5-(2-amino-6-chloro-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate (29)

[0459] In an oven-dried flask, ((2S,4R,5R)-4-acetoxy-5-(2-amino-6,8-dioxo-1,6,7,8-tetrahydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate (28) (13 g, 35.4 mmol), benzyltriethylammonium chloride (16.1 g, 70.8 mmol) and N,N-dimethylaniline (4.9 mL, 38.9 mmol) were dissolved in 400 mL of dry MeCN. POCl was added. 3 (16.2 mL, 177.0 mmol). The reaction mixture was stirred at 105 °C for 8 h. The reaction mixture was concentrated in vacuo. The resulting residue was dissolved in dichloromethane and washed with water and then with 5% NaHCO 3 The organic phase was washed with anhydrous Na 2SO 4 The crude product was purified by column chromatography using dichloromethane-methanol (120:1) as eluent to give 6.1 g of ((2S,4R,5R)-4-acetoxy-5-(2-amino-6-chloro-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate (29) as a white solid in 45% yield. f =0.60 (dichloromethane-methanol=40:1)

[0460] Step 4: ((2S,4R,5R)-4-Acetoxy-5-(2-amino-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate (30)

[0461] To ((2S,4R,5R)-4-acetoxy-5-(2-amino-6-chloro-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate (29) (6.1 g, 15.8 mmol) dissolved in a mixture of THF (150 mL) and triethylamine (2.2 mL, 15.8 mmol) was added 10% Pd / C (610 mg). The mixture was stirred at room temperature under hydrogen (50 psi) atmosphere for 5 h. The catalyst was then filtered through a pad of celite and the solvent was evaporated to give the crude product, which was purified by column chromatography using dichloromethane-methanol (60:1) as the eluent. ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate (30) (3.2 g) was isolated as a white foam in 57% yield. f =0.4 (dichloromethane-methanol=20:1).

[0462] Step 5: ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 29

[0463] To ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate (30) (2.2 g, 6.3 mmol) dissolved in 50 mL of anhydrous DMF was added K 2 CO 3(1.3 g, 9.4 mmol, 1.5 eq.). The reaction mixture was stirred for 30 min, and 3-bromopropyne (0.98 mL, 12.6 mmol, 2 eq.) was added. The stirred reaction mixture was maintained at 45 °C for 3 h. The mixture was then concentrated under reduced pressure, and the resulting residue was purified by column chromatography using dichloromethane-methanol (160:1) as eluent to give 1.8 g of ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, compound 29, as a white foam in 75% yield. HPLC purity (98.2%). R f =0.50 (dichloromethane-methanol=40:1). 1 H NMR (CDCl 3 ,400MHz)δ8.00(s,1H),5.98-5.99(d,1H,J=1.6Hz),5.80-5.82(d,1H,J=6.4Hz),4.91(s,2H),4.59(d,2H ,J=2.4Hz),4.44-4.51(m,2H),4.16-4.21(m,1H),2.39(t,1H,J=2.4Hz),2.12(s,3H),2.07(s,3H).ESI-MS m / z 390.1[M+H] + ,412.1[M+Na] + .

[0464] Embodiment 30: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-

[0465] yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one, compound 30

[0466]

[0467] Compound 30 was prepared from compound 29 using the procedure outlined for the preparation of compound 4 from compound 3.

[0468] ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, compound 29 (1.37 g, 3.52 mmol) was treated with saturated ammonia in methanol. The flask was sealed and the reaction mixture was heated at 40°C and stirred overnight. The volatiles were evaporated under reduced pressure and the residue was purified by column chromatography using dichloromethane-methanol (30:1) as eluent to give 800 mg of 2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one, compound 30, as a white solid in 75% yield with an HPLC purity of 98.9%. f =0.30 (dichloromethane-methanol=10:1). 1 H NMR (DMSO, 400MHz) δ8.01 (s, 1H), 6.37 (s, 1H), 5.61 (d, 1H, J = 2.8Hz), 5.43-5.44 (d, 1H, J = 4.4Hz), 4.84-4.88 (m, 1H), 4.68-4.71 (t, 1H, J = 2Hz) ,4.62-4.63(d,2H,J=2.4Hz),4.17-4.20(m,1H,),3.42-3.49(m,2H,),3.39-3.40(t,1H,J=2Hz),2.37-2.44(m,1H),1.83-1.88(m,1H).ESI-MS m / z 306.1[M+H] + ,328.1[M+Na] + .

[0469] Embodiment 31: ((2R,3R,4S,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate, Compound 31

[0470]

[0471] Compound 31 was prepared according to the following multi-step procedure.

[0472]

[0473] Step 1: ((2R,3R,4S,5R)-4-Acetoxy-5-(2-amino-8-(benzyloxy)-6-oxo-1,6-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate (31)

[0474] A solution of 2-amino-8-(benzyloxy)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (18) (11.2 g, 28.6 mmol) in anhydrous MeCN (150 mL) containing triethylamine (15.9 ml, 4.0 equiv) was treated with acetic anhydride (6.8 mL, 71.6 mmol, 2.5 equiv). The reaction mixture was stirred at room temperature overnight, diluted with ethyl acetate (500 mL) and poured into water. The layers were separated and the aqueous layer was extracted twice with ethyl acetate. The combined organic layers were washed with brine and washed with anhydrous Na 2 SO 4 The residue was dried and concentrated under reduced pressure. The obtained residue was purified by silica gel column chromatography using dichloromethane-methanol (40:1) as eluent to give 9.2 g of ((2R,3R,4S,5R)-4-acetoxy-5-(2-amino-8-(benzyloxy)-6-oxo-1,6-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate (31) as white foam in a 67.6% yield; R f =0.2 (dichloromethane-methanol=20:1).

[0475] Step 2: ((2R,3R,4S,5R)-4-Acetoxy-5-(2-amino-6,8-dioxo-1,6,7,8-tetrahydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate (32)

[0476] Phosphorus oxychloride (1.7 mL, 17.9 mmol, 1.0 equiv) was added to ((2R,3R,4S,5R)-4-acetoxy-5-(2-amino-8-(benzyloxy)-6-oxo-1,6-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate (31) (8.5 g, 17.9 mmol) dissolved in 100 mL of anhydrous MeCN with stirring for 1 h at room temperature. MeOH (10 mL) and excess solid NaHCO 3 Add to the reaction mixture. The mixture was stirred for 20 minutes and then concentrated in vacuo. The resulting residue was purified by column chromatography using dichloromethane-methanol (30:1) as eluent to give 5.7 g of ((2R,3R,4S,5R)-4-acetoxy-5-(2-amino-6,8-dioxo-1,6,7,8-tetrahydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate (32) as a white foam in 82% yield; R f =0.30 (dichloromethane-methanol=10:1).

[0477] Step 3: ((2R,3R,4S,5R)-4-Acetoxy-5-(2-amino-6-chloro-8-oxo-7,8-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate (33)

[0478] In an oven-dried flask, ((2R,3R,4S,5R)-4-acetoxy-5-(2-amino-6,8-dioxo-1,6,7,8-tetrahydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate (32) (5.7 g, 14.8 mmol) was dissolved in 60 mL of phosphorus oxychloride. The reaction mixture was stirred at 75 °C overnight and concentrated in vacuo. The resulting residue was purified by column chromatography using dichloromethane-methanol (100:1) as eluent to give 2.7 g of ((2R,3R,4S,5R)-4-acetoxy-5-(2-amino-6-chloro-8-oxo-7,8-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate (33) as a white solid in 45% yield. f =0.60 (dichloromethane-methanol=30:1).

[0479] Step 4: ((2R,3R,4S,5R)-4-Acetoxy-5-(2-amino-8-oxo-7,8-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate (34)

[0480] To ((2R,3R,4S,5R)-4-acetoxy-5-(2-amino-6-chloro-8-oxo-7,8-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate (33) (2.7 g, 6.7 mmol) dissolved in a mixture of anhydrous methanol (30 mL) and tetrahydrofuran (10 mL) was added 10% Pd / C (270 mg). The mixture was stirred at room temperature under a hydrogen (50 psi) atmosphere for 5 h. The catalyst was filtered off through celite, the solvent was evaporated, and the crude product was purified by column chromatography using dichloromethane-methanol (40:1) as eluent to afford 1 g of ((2R,3R,4S,5R)-4-acetoxy-5-(2-amino-8-oxo-7,8-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate (34) as a white foam in 42% yield. f =0.2 (dichloromethane-methanol=20:1).

[0481] Step 5:((2R,3R,4S,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate, Compound 31

[0482] To ((2R,3R,4S,5R)-4-acetoxy-5-(2-amino-8-oxo-7,8-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate (34) (1 g, 2.7 mmol) dissolved in 20 mL of anhydrous DMF was added K 2 CO 3 (0.56 g, 4 mmol, 1.5 equiv.). 3-Bromopropyne (0.43 mL, 5.4 mmol, 2 equiv.) was added to the reaction mixture and stirring was continued at 45 °C for 5 h. The mixture was concentrated under reduced pressure. The residue obtained was purified by column chromatography using dichloromethane-methanol (100:1) as eluent to give 750 mg of ((2R, 3R, 4S, 5R)-4-acetoxy-5-(2-amino-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate, compound 31, as a white foam, 70% yield, HPLC purity of 98.4%. R f =0.60 (dichloromethane-methanol=30:1). 1 H NMR (CDCl 3 ,400MHz)δ8.03(s,1H),6.10-6.15(m,2H),5.53-5.55(m,0.5H),5.40-5.42(m,0.5H),4.96(s,2H),4.60( d,2H,J=4Hz),4.44-4.57(m,2H),4.29-4.33(m,1H),2.39(t,1H,J=4Hz),2.15(s,3H),2.10(s,3H).ESI-MS m / z408.1[M+H] + ,430.1[M+Na] + .

[0483] Embodiment 32: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one, Compound 32

[0484]

[0485] Compound 32 was prepared from compound 31 using the procedure outlined for the preparation of compound 4 from compound 3.

[0486] To ((2R,3R,4S,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate, Compound 31 (500 mg, 1.23 mmol) was added saturated methanolic ammonia solution. The reaction mixture was heated to 40°C and stirred overnight. The volatiles were evaporated under reduced pressure and the solid residue was purified by column chromatography using dichloromethane-methanol (40:1) as eluent to afford 300 mg of 2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one, compound 32, as a white solid in 76% yield with an HPLC purity of 98.6%. f =0.30 (dichloromethane-methanol=10:1). 1 H NMR(DMSO,400MHz)δ8.06(s,1H),6.44(s,2H,NH 2 ),5.85(d,1H,J=4Hz,1'-H),5.71(d,1H,J=4Hz,2'-OH),5.25-5.35(m,1H,2'-H),5.14-5.15(m,0.5H,4'-H),5.00-5.10(m,0.5H,half 4'-H),4.96(t,1H,J=4Hz,5'-OH),4.65(d,2H,J=4Hz,CH 2 ),4.09-4.19(m,1H,3'-H),3.51-3.62(m,2H,5'-H),3.41(t,1H,J=4Hz).ESI-MS m / z 324.1[M+H] + ,346.1[M+Na] + .

[0487] Alternative synthetic methods for compounds 5, 26 and 27.

[0488] Example 5A: 2-Amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 5

[0489]

[0490] Compound 5 was also prepared according to the following alternative multi-step method.

[0491]

[0492] Step-1: 6-Chloro-N 4 -(4-Methoxybenzyl)pyrimidine-2,4,5-triamine (35)

[0493] At 0 ° C, 4-methoxybenzylamine (114.8 g, 83.728 mol) was added to a stirred solution mixture of 4,6-dichloropyrimidine-2,5-diamine [55583-59-0] (100 g, 55.81 mol) and TEA (169 mL, 167.45 mol) in ethanol (1.0 L), and the resulting reaction mixture was stirred at reflux temperature for 18 h. The solvent was evaporated under reduced pressure, and the thick material was poured into ice-cold water and stirred for 30 minutes. The precipitated solid was collected by filtration, washed with water and dried under vacuum to obtain 6-chloro-N-(2-chloro-4-yl)-pyrimidine as a brown solid. 4 -(4-methoxybenzyl)pyrimidine-2,4,5-triamine (35) (100 g, 64%). ES+, m / z 280.1 [M+H] + ; C 12 H 14 C1N 5 O; 1 H NMR (500 MHz, DMSO-d 6 ): δ8.25(d,J=8.5Hz,2H),6.92(t,J=6.0Hz,1H),7.87(d,J=8.5Hz,2H),5.63(s,2H),4.47(d,J=5.5Hz,2H),3.91(s,2H),3.72(s,3H).

[0494] Step-2: 2-Amino-6-chloro-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (36)

[0495] 6-Chloro-N 4 A mixture of -(4-methoxybenzyl)pyrimidine-2,4,5-triamine (35) (50 g, 17.92 mol) and 1,1'-carbonyldiimidazole (100 g, 61.64 mol) in acetonitrile (500 mL) was stirred at reflux temperature for 18 h. The reaction mixture was cooled to room temperature and concentrated under reduced pressure. Ice-cold water was added to the resulting residue and stirred at room temperature for 30 minutes. The precipitated solid was filtered, washed with water and dried to give a brown solid 2-amino-6-chloro-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (36) (50 g, 91%); C 13 H12 C1N 5 O 2 ; 1 H NMR (500 MHz, DMSO-d 6 ): δ11.31(s,1H),7.23(d,J=9.0Hz,2H),6.88(d,J=5.0Hz,2H),6.62(s,2H),4.80(s,2H),3.71(s,3H).

[0496] Step-3: 2-Amino-6-(benzyloxy)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (37)

[0497] Sodium hydroxide (9.967 g, 262.29 mmol) was added to a suspension of 2-amino-6-chloro-9-(4-methoxybenzyl)-7,9-dihydro-8H-purine-8-one (36) (40 g, 131.14 mmol) in benzyl alcohol (45.0 mL). The resulting reaction mixture was stirred at 120 ° C for 18 h. The reaction mixture was quenched with ice water (200 mL), ether (150 mL) was added, and stirred for 15 minutes. The precipitated solid was filtered, washed with water and dried to give a brown solid 2-amino-6-(benzyloxy)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purine-8-one (30 g, 60%). ES+, m / z 378.1 [M+H] + ; C 20 H 19 N 5 O 3 ; 1 HNMR (400 MHz, DMSO-d 6 ): δ10.81(s,1H),7.48(d,J=7.2Hz,2H),7.40–7.36(t,J=7.6Hz,2H),7.34–7.31(t,J=5.2Hz,1H), 7.21(d,J=8.4Hz,2H),6.87(d,J=8.4Hz,2H),6.27(s,2H),5.41(s,2H),4.78(s,2H),3.71(s,3H).

[0498] Step-4: 2-Amino-6-(benzyloxy)-9-(4-methoxybenzyl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one (38)

[0499] At 0°C, propargyl bromide (7.1 ml, 63.66 mmol) was added to 2-amino-6-(benzyloxy)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (37) (20 g, 53.05 mmol), K 2 CO 3 (10.98 g, 79.57 mmol) in a suspension of DMF (100 mL) and stirred at room temperature for 18 h. The reaction mixture was quenched with ice water (200 mL), ether (150 mL) was added, and stirred for 15 minutes. The precipitated solid was filtered, washed with water and dried to give a brown solid 2-amino-6-(benzyloxy)-9-(4-methoxybenzyl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purine-8-one (20 g, 91%). ES+, m / z 416.1[M+H] + ; C 23 H 21 N 5 O 3 ; 1 H NMR (400 MHz, DMSO-d 6 ): δ7.52(d,J=7.2Hz,2H),7.38(t,J=7.6Hz,2H),7.32(t,J=5.2Hz,1H),7.22(d,J=8.4Hz,2H),6.81( d,J=8.4Hz,2H),6.27(s,2H),5.44(s,2H),4.82(s,2H),4.56(s,2H),3.71(s,3H),3.32-3.26(m,1H).

[0500] Step-5: 2-Amino-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (39)

[0501] Under argon atmosphere, trifluoromethanesulfonic acid (27 g, 180.72 mmol) was added to a suspension of 2-amino-6-(benzyloxy)-9-(4-methoxybenzyl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one (25 g, 60.24 mmol) in trifluoroacetic acid (21 mL, 180.72 mmol) at 0°C, and the resulting reaction mixture was stirred at room temperature under argon atmosphere for 18 h. The reaction mixture was quenched with ice-cold water and heated with saturated NaHCO under vigorous stirring. 3The solution was basified and filtered. The residual solid was dissolved in ethyl acetate, stirred for 30 minutes, filtered and dried to give 2-amino-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (12 g, 36%) as a brown solid. ES+, m / z 206.1 [M+H] + ; C 8 H 7 N 5 O 2 ; 1 H NMR (400 MHz, DMSO-d 6 ): δ11.32(s,1H),6.74(s,2H),4.53(s,2H),3.14(s,1H).

[0502] Step-6: N-(6,8-Dioxo-7-(prop-2-yn-1-yl)-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (40)

[0503] Acetic anhydride (4.85 mL, 47.56 mmol) was added to a solution of 2-amino-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (6.5 g, 31.70 mmol) in DMF (65 mL) at room temperature and argon atmosphere, and the resulting reaction mixture was stirred at room temperature for 18 hours under argon atmosphere. The reaction mixture was cooled to 0 ° C (solid formed under stirring) and stirred for 30 minutes. The product was filtered, washed with ethanol, and dried in vacuo to give N-(6,8-dioxo-7-(prop-2-yn-1-yl)-6,7,8,9-tetrahydro-1H-purine-2-yl)acetamide (4 g, 51.2%) as a brown solid. ES+, m / z 248.1 [M+H] + ; C 10 H 9 N 5 O 3 ; 1 H NMR (400 MHz, DMSO-d 6 ): δ11.83(s,2H),4.61(s,2H),3.23(s,1H),2.16(s,3H).

[0504] Step-6: (2R,3S,4R,5R)-5-(2-acetamido-6,8-dioxo-7-(prop-2-yn-1-yl)-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxy-2-((benzoyloxy)methyl)tetrahydrofuran-3-yl benzoate (41)

[0505] N-(6,8-Dioxo-7-(prop-2-yn-1-yl)-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (400 mg, 1.61 mmol), (3R,4S,5R)-4-(benzoyloxy)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester (716 mg, 1.61 mmol) [85026-60-4] (see M. Popsavin et al., Bioorg. Med. Chem. Lett., 2012, 22, p. 6700 and G. Gosselin et al., J. Het. Chem., 1982, 19, p. 597), BSA (983 mg, 4.85 mmol) and MeCN (40 mL) were vigorously mixed for 45 minutes until a homogeneous solution was obtained. TMSOTf (540 mg, 2.42 mmol) was then added to the reaction and placed in a preheated oil bath at 75°C. After 4 hours, the reaction was cooled to room temperature and the solvent was removed by rotary evaporation. The resulting solid was dissolved in ethyl acetate (100 mL) and washed with saturated NaHCO 3 Extraction with aqueous solution (2×30 mL). 2 SO 4 The organic phase was dried and concentrated. 2 , 0-40% ethyl acetate-petroleum ether) to purify the crude product to obtain 190 mg (18.64%) of a light yellow solid (2R,3S,4R,5R)-5-(2-acetamido-6,8-dioxo-7-(prop-2-yn-1-yl)-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxy-2-((benzoyloxy)methyl)tetrahydrofuran-3-ylbenzoate. ES+, m / z 630.1 [M+H] + ; C 31 H 27 N 5 O 10 ; 1 H NMR (400 MHz, DMSO-d 6 ): δ11.89(s,1H),8.02(d,J=6.8Hz,2H),7.86(d,J=7.2Hz,2H),7.68–7.61(m,2H),7.54–7.45(m,5H),6.48–6.46(m,1H),5.83–5 .79(m,2H),4.76(d,J=6.0Hz,1H),4.68(s,2H),4.64(d,J=4.8Hz,1H),4.57–4.53(m,1H),3.29(s,1H),2.15(s,3H),2.07(s,3H).

[0506] Step 7:2-Amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 5

[0507] (2R,3S,4R,5R)-5-(2-acetamido-6,8-dioxo-7-(prop-2-yn-1-yl)-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxy-2-((benzoyloxy)methyl)tetrahydrofuran-3-yl benzoate (500 mg, 0.79 mmol) was dissolved in methanol (10 mL). K was added. 2 CO 3 (164 mg, 1.19 mmol), and the reaction was stirred at room temperature for 16 h. Acetic acid (96 mg, 1.58 mmol) was added, and the reaction was concentrated by rotary evaporation. The crude product was purified by GRACE reverse phase (MeCN-0.01% HCO 2 H of H 2 O solution) to give 120 mg (45%) of 2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, compound 5, as an off-white solid. ES+, m / z 338.0 [M+H] + ; C 13 H 15 N 5 O 6 ; 1 H NMR (500 MHz, DMSO-d 6 ): δ11.56(s,1H),6.94(s,2H),5.73(s,2H),5.47(d,J=2.8Hz,1H),4.62(d,J=2Hz,2H),4 .50(s,2H),3.91–3.88(m,2H),3.68–3.65(m,1H),3.59–3.54(m,1H),3.25–3.24(m,1H).

[0508] Example 26A: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 26

[0509]

[0510] Using the same general procedure as described in Example 5A, compound 26 was also synthesized according to the following alternative multi-step procedure.

[0511]

[0512] Step-1: ((2S,4R,5R)-5-(2-acetamido-6,8-dioxo-7-(prop-2-yn-1-yl)-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate (42)

[0513] A solution of N-(6,8-dioxo-7-(prop-2-yn-1-yl)-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (1 g, 4.04 mmol), (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester [4613-71-2] (see PJ Bolon et al., Tetrahedron, 1994, 50, 7747 pages) (1.30 g, 4.04 mmol) and BSA (2.45 g, 12.14 mmol) in dichloromethane (100 mL) was vigorously stirred at 70° C. for 45 minutes until a homogeneous solution was formed. The reaction mixture was cooled to room temperature and concentrated under vacuum. The crude concentrate was dissolved in MeCN (50 mL), then TMSOTf (1.35 mL, 6.07 mmol) was added and placed in a preheated oil bath at 90 °C. After 16 hours, the reaction was cooled to room temperature and the solvent was removed by rotary evaporation. The resulting solid was dissolved in EtOAc (200 mL) and washed with saturated NaHCO 3 Extraction with aqueous solution (2×50 mL). 2 SO 4 The organic phase was dried and concentrated. 2 , 0-40% ethyl acetate-petroleum ether) to purify the crude product to obtain 700 mg (33.98%) of a light yellow solid ((2S,4R,5R)-5-(2-acetamido-6,8-dioxo-7-(prop-2-yn-1-yl)-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate. ES+, m / z 510.1 [M+H] + ; C 24 H 23 N 5 O 8 .

[0514] Step 2:2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 26

[0515] To ((2S,4R,5R)-5-(2-acetamido-6,8-dioxo-7-(prop-2-yn-1-yl)-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate (1 g, 1.96 mmol) in methanol (20 mL) was added K 2 CO 3 (407 mg, 2.9 mmol). The reaction mixture was stirred at room temperature for 16 h. Acetic acid (236 mg, 3.9 mmol) was added and the mixture was concentrated by rotary evaporation. The crude product was purified by GRACE reverse phase (MeCN-0.01% HCO 2 H of H 2 O solution) to give 200 mg (32%) of 2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione as an off-white solid. ES+, m / z 322.0 [M+H] + ; C 13 H 15 N 5 O 5 . 1 H NMR (400 MHz, DMSO-d 6 ): δ11.03(s,1H),6.59(s,2H),5.51(d,J=2.8Hz,1H),5.40(d,J=4.0Hz,1H),4.80(d,J=2.8Hz,1H)4 .70(s,1H),4.58(d,J=1.6Hz,2H),4.14(m,1H),3.45(m,2H),3.22(s,1H),2.34(m,1H),1.82(m,1H).

[0516] Example 27A: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 27

[0517]

[0518] Using the same general procedure as described in Example 5A, compound 27 was also synthesized according to the following alternative multi-step procedure.

[0519]

[0520] Step-1: ((2R,3R,4S,5R)-5-(2-acetamido-6,8-dioxo-7-(prop-2-yn-1-yl)-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxy-3-fluorotetrahydrofuran-2-yl)methyl benzoate (43)

[0521] A solution of N-(6,8-dioxo-7-(prop-2-yn-1-yl)-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (500 mg, 2.042 mmol), (2S,3S,4R,5R)-5-((benzoyloxy)methyl)-4-fluorotetrahydrofuran-2,3-diacetic acid diester (see RFSchinazi et al., Het. Comm, 2015, 21, 315 pages) (1.376 g, 4.04 mmol) and BSA (331 mg, 2.2 mmol) in 1,2-dichloroethane (50 mL) was vigorously stirred at 70 ° C for 45 minutes until a homogeneous solution was formed. The reaction mixture was cooled to room temperature and concentrated under vacuum. The crude concentrate was dissolved in MeCN (50 mL), then TMSOTf (0.186 mL, 0.81 mmol) was added and placed in a preheated oil bath at 90 °C. After 16 hours, the reaction was cooled to room temperature and the solvent was removed by rotary evaporation. The resulting solid was dissolved in ethyl acetate (200 mL) and washed with saturated NaHCO 3 Extraction with aqueous solution (2×50 mL). 2 SO 4 The organic layer was dried and concentrated. 2 , 0-40% ethyl acetate-petroleum ether) to purify the crude product to obtain 200 mg (18.25%) of a light yellow solid ((2R,3R,4S,5R)-5-(2-acetamido-6,8-dioxo-7-(prop-2-yn-1-yl)-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxy-3-fluorotetrahydrofuran-2-yl)methyl benzoate. ES+, m / z 528.1 [M+H] + ; C 24 H 22 FN 5 O 8 . 1 H NMR (400 MHz, DMSO-d 6): δ11.80(s,1H),9.32(s,1H),8.03(d,J=7.2Hz,2H),7.64–7.60(t,J=7.2Hz,1H),7.49–7.45(t,J=8.0Hz,2H),6.22(d,J=5.6Hz,1H),5.93–5 .87(m,1H),5.53–5.48(m,1H),5.14–5.09(m,1H),4.82(s,2H),4.75–4 .69(m,1H),4.68–4.54(m,1H),2.33(s,3H),2.29(m,1H),2.14(s,3H).

[0522] Step-2: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 27

[0523] To ((2R,3R,4S,5R)-5-(2-acetamido-6,8-dioxo-7-(prop-2-yn-1-yl)-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxy-3-fluorotetrahydrofuran-2-yl)methyl benzoate (500 mg, 0.948 mmol) in MeOH (10 mL) was added K 2 CO 3 (131 mg, 0.948 mmol). The reaction mixture was stirred at room temperature for 16 h. Acetic acid (114 mg, 1.896 mmol) was added and the reaction mixture was concentrated by rotary evaporation. The crude product was purified by reverse phase GRACE (MeCN-0.01% HCO 2 H of H 2 O solution) to give 120 mg (37.38%) of 2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, compound 27, as a light brown solid. ES+, m / z 340.1 [M+H] + ; C 13 H 14 FN 5 O 5 . 1H NMR (400MHz, DMSO-d6): δ11.00(s,1H),6.59(s,2H),5.79(d,J=6.4Hz,1H),5.62(d,J=7.6Hz,1H),5.24–5.17(m,1H) ,5.09(d,J=3.6Hz,1H),4.96–4.93(t,J=6.8Hz,1H),4.60(s,2H),4.15–4.16(m,1H),3.59–3.50(m,2H),3.24(s,1H).

[0524] Alternative synthetic method for compound 32.

[0525] Example 32A: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one, Compound 32

[0526]

[0527] Compound 32 was also prepared according to the following alternative multi-step procedure.

[0528]

[0529] Step-1: N-(6-Chloro-9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide (44)

[0530] Acetic anhydride (13.04 ml, 85.224 mmol) was added to a solution of 2-amino-6-chloro-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (36) (13.0 g, 42.622 mmol) in DMF (100 mL) at room temperature under argon atmosphere, and the resulting reaction mixture was stirred at 140°C for 18 hours. The reaction mixture was cooled to 0°C (solid formed under stirring) and stirred for 30 minutes. The product was filtered, washed with water, and dried in vacuo to give N-(6-chloro-9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide (9.0 g, 51.2%) as a brown solid; ES+, m / z 348.1 [M+H] + ,C 15 H 14 C1N 5 O 3 ; 1 H NMR (400 MHz, DMSO-d 6): δ11.90(s,1H),10.55(s,1H),7.33(d,J=8.8Hz,2H),6.87(d,J=8.4Hz,2H),4.87(s,2H),3.71(s,3H),2.13(s,3H).

[0531] Step-2: N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide (45)

[0532] 10% Pd / C (3.5 g) was added to a solution of N-(6-chloro-9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide (15.0 g, 28.81 mmol) in methanol (200 mL) and THF (400 mL). The reaction mixture was hydrogenated with hydrogen at a pressure of 80 psi at room temperature for 24 hours in a Parr shaker bottle. The reaction mixture was filtered through a celite pad and the filtrate was evaporated to give a crude solid. The solid was dissolved in ether, stirred for 15 minutes, filtered and repeated. The solid was dried under vacuum to a light brown solid to give N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide (10.5 g, 77.6%). 1 H NMR and LC-MS showed acetylation (37%) ES+, m / z 314.2 [M+H] + ; C 15 H 15 N 5 O 3 ; and deacetylated (43%) ES+, m / z 272.2 [M+H] + ; C 13 H 13 N 5 O 2 The crude mixture was used for the next step. 1 HNMR (400 MHz, DMSO-d 6 ): δ10.55(s,1H),8.09(s,1H),7.33(d,J=8.8Hz,2H),6.87(d,J=8.8Hz,2H),4.93(s,2H),3.72(s,3H),2.24(s,3H).

[0533] Step-3: N-(9-(4-methoxybenzyl)-8-oxo-7-(prop-2-yn-1-yl)-8,9-dihydro-7H-purin-2-yl)acetamide (46)

[0534] At 0°C, propargyl bromide (6.0 mL, 40.255 mmol) was added to N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide (45) (10.5 g, 33.546 mmol), K 2 CO 3 (6.95 g, 50.319 mmol) in a suspension of DMF (50 mL) and stirred at room temperature for 18 h. The reaction mixture was quenched with ice water (200 mL), ether (150 mL) was added, and stirred for 15 minutes. The precipitated solid was filtered, washed with water and dried to give a brown solid N-(9-(4-methoxybenzyl)-8-oxo-7-(prop-2-yn-1-yl)-8,9-dihydro-7H-purin-2-yl)acetamide (8.5 g, 72.21%). ES+, m / z 352.2 [M+H] + ; C 18 H 17 N 5 O 3 ; 1 H NMR (400 MHz, DMSO-d 6 ): δ10.41(s,1H),8.32(s,1H),7.35(d,J=8.4Hz,2H),6.88(d,J=8.4Hz,2H),4.92(s,2H),4.73(s,2H),3.71(s,3H),3.42(s,1H),2.15(s,3H).

[0535] Step-4: 2-Amino-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one (47)

[0536] Under argon atmosphere, trifluoromethanesulfonic acid (4.5 ml) was added to a suspension of N-(9-(4-methoxybenzyl)-8-oxo-7-(prop-2-yn-1-yl)-8,9-dihydro-7H-purin-2-yl)acetamide (4.5 g, 12.82 mmol) in trifluoroacetic acid (4.5 mL) at 0°C, and the resulting reaction mixture was stirred at room temperature for 18 hours. The reaction mixture was quenched with ice-cold water and heated to saturated NaHCO under vigorous stirring. 3 The solution was basified and filtered. The residual solid was dissolved in ethyl acetate, stirred for 30 minutes, filtered and dried to give 2-amino-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one (2.0 g, 82.64%) as a brown solid. ES+, m / z 190.1 [M+H] + ; C 8 H 7 N 5 O2 ; 1 H NMR (400 MHz, DMSO-d 6 ): δ11.32(s,1H),7.57(s,1H),5.60(s,2H),4.46(s,2H),3.22(s,1H).

[0537] Step-5: N-(8-Oxo-7-(prop-2-yn-1-yl)-8,9-dihydro-7H-purin-2-yl)acetamide (48)

[0538] At room temperature and argon atmosphere, acetic anhydride (7 mL, 68.78 mmol) was added to a DMF (65 mL) solution of 2-amino-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purine-8-one (6.5 g, 34.39 mmol), and the resulting reaction mixture was stirred at 140 ° C for 18 hours. The reaction mixture was cooled to 0 ° C and stirred for 30 minutes, thereby forming a solid. The product was filtered, washed with water, and dried in vacuo to give N-(8-oxo-7-(prop-2-yn-1-yl)-8,9-dihydro-7H-purine-2-yl)acetamide (4 g, 50.34%) as a brown solid; C 10 H 9 N 5 O 3 ; 1 H NMR (500 MHz, DMSO-d 6 ): δ9.80(s,1H),7.76(s,1H),6.17(s,1H),4.53(s,2H),3.24(s,1H),2.11(s,3H).

[0539] Step-6: ((2R,3R,4S,5R)-5-(2-acetamido-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purin-9-yl)-4-acetoxy-3-fluorotetrahydrofuran-2-yl)methyl benzoate (49)

[0540] N-(8-oxo-7-(prop-2-yn-1-yl)-8,9-dihydro-7H-purin-2-yl)acetamide (2.0 g, 8.65 mmol), (2S,3S,4R,5R)-5-((benzoyloxy)methyl)-4-fluorotetrahydrofuran-2,3-diacetic acid diester (5.887 g, 17.316 mmol), BSA (5.283 g, 25.974 mmol) and dichloroethane (50 mL). The resulting reaction mixture was stirred at 80 ° C for 30 minutes under argon. The reaction mixture was concentrated under reduced pressure and the residue was diluted with ACN (100 mL) and TMSOTf (2.886 g, 12.987 mmol) was added and placed in a preheated oil bath at 80 ° C. After 18 hours, the reaction was cooled to room temperature and the solvent was removed by rotary evaporation. The resulting solid was dissolved in ethyl acetate (100 mL) and washed with saturated NaHCO 3 Wash with aqueous solution (2×30 mL). 2 SO 4 The organic phase was dried and concentrated. 2 , 0-40% ethyl acetate-petroleum ether) to purify the crude product to obtain (2 g, 47.16%) of a light yellow solid ((2R,3R,4S,5R)-5-(2-acetamido-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purin-9-yl)-4-acetoxy-3-fluorotetrahydrofuran-2-yl)methyl benzoate. ES+, m / z 512.2 [M+H]+; C 24 H 22 FN 5 O 7 ; LC-MS showed 83.5% of the desired m / z, 1 H-NMR showed the desired signals along with some solvent residues. The crude compound was used in the next step without isolation.

[0541] Step 7: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one, Compound 32

[0542] ((2R,3R,4S,5R)-5-(2-acetamido-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purine-9-yl)-4-acetoxy-3-fluorotetrahydrofuran-2-yl)methyl benzoate (5.0 g, 11.13 mmol) was dissolved in methanolic ammonia (7M) (500 mL) in a sealed container. The reaction was stirred at room temperature for 5 days. The reaction mixture was concentrated by rotary evaporation to give a thick solid. The solid was dissolved in a minimum amount of methanol and acetonitrile (50 mL), added and stirred for 2 hours. The solid was filtered to give (1.4 g, 38.93%) of 2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one, Compound 32, as a light brown solid. ES+, m / z 324.1 [M+H] + ; C 13 H 14 N 5 O 4 ; 1 H NMR (500 MHz, DMSO-d 6 ): δ8.05(s,1H),6.42(s,2H),5.84(d,J=6Hz,1H),5.71(d,J=7.5Hz,1H),5.32–5.27(m,1H),),5.12–5 .01(m,1H),4.96–4.93(t,J=6Hz,1H),4.65(s,2H),4.17–4.10(m,1H),3.63–3.51(m,2H),3.40(s,1H).

[0543] Embodiment 33: 2-Amino-7-benzyl-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 33

[0544]

[0545] Using the same general procedure as described in Example 5A, compound 33 was also synthesized according to the following multi-step method.

[0546]

[0547] Step-1: 2-Amino-7-benzyl-6-(benzyloxy)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (50)

[0548] Benzyl bromide (1.36 g, 7.95 mmol) was added to 2-amino-6-(benzyloxy)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (2 g, 5.305 mmol) and K at 0°C. 2 CO 3 (2.1 g, 15.91 mmol) in a suspension of DMF (20 mL) and stirred at room temperature for 18 h. The reaction mixture was quenched with ice water (120 mL), diluted with ether (80 mL) and stirred for 15 minutes. The precipitated solid was filtered, washed with water and dried to give an off-white solid 2-amino-7-benzyl-6-(benzyloxy)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (2.0 g, 83%); ES+, m / z 468.2 [M+H] + ; C 27 H 25 N 5 O 3 : 1 H NMR (400 MHz, DMSO-d 6 ):δ7.32–7.20(m,10H),7.12–7.09(m,2H),6.87(d,J=12Hz,2H),6.41(s,2H),5.34(s,2H),4.95(s,2H),4.85(s,2H),3.71(s,3H).

[0549] Step-2: 2-Amino-7-benzyl-7,9-dihydro-1H-purine-6,8-dione (51)

[0550] Under argon atmosphere, trifluoromethanesulfonic acid (2.2 mL, 25.64 mmol) was added to a suspension of 2-amino-7-benzyl-6-(benzyloxy)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (2 g, 4.28 mmol) in trifluoroacetic acid (2.09 mL, 25.64 mmol) at 0°C, and the resulting reaction mixture was slowly warmed to room temperature and stirred for 3 hours. The reaction mixture was quenched with ice-cold water and heated with saturated NaHCO under vigorous stirring. 3 The solution was basified and filtered. The residual solid was dissolved in ethyl acetate, stirred for 30 minutes, filtered and dried to give 2-amino-7-benzyl-7,9-dihydro-1H-purine-6,8-dione (0.5 g, 45%) as a brown solid. ES+, m / z 258.1 [M+H] + ; C 12 H 11 N 5 O 2 ; 1H NMR (400 MHz, DMSO-d 6 ): 1 H NMR: δ11.16(s,1H),10.64(s,1H),7.30–7.22(s,5H),6.37(s,2H),4.93(s,2H).

[0551] Step-3: N-(7-Benzyl-6,8-dioxo-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (52)

[0552] Acetic anhydride (0.28 mL, 5.36 mmol) was added to a solution of 2-amino-7-benzyl-7,9-dihydro-1H-purine-6,8-dione (0.500 g, 1.945 mmol) in DMF (5 mL) at ambient temperature and under an argon atmosphere, and the resulting reaction mixture was heated at 130 ° C for 3 hours under an argon atmosphere. The reaction mixture was cooled to 0 ° C (solid formed under stirring) and stirred for 30 minutes. The product was filtered, washed with ethanol, and dried in vacuo to give N-(7-benzyl-6,8-dioxo-6,7,8,9tetrahydro-1H-purin-2-yl)acetamide (0.3 g, 51%) as a brown solid. The crude compound was used directly in the next step. C 14 H 13 N 5 O 3 : 1 H NMR (400 MHz, DMSO-d 6 ): δ12.01(s,1H),11.76(s,1H),11.65(s,1H),7.32–7.31(m,5H),5.01(s,2H),2.14(s,3H).

[0553] Step-4: ((2S,4R,5R)-5-(2-acetamido-7-benzyl-6,8-dioxo-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate (53)

[0554] N-(7-benzyl-6,8-dioxo-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (300 mg, 1.0 mmol), (3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester (387.6 mg, 1.204 mmol), BSA (0.76 mL, 3.010 mmol) dissolved in 1,2-dichloroethane (10 mL) were stirred at 80 ° C for 30 minutes under argon. The reaction mixture was concentrated under reduced pressure, the residue was diluted with anhydrous acetonitrile (10 mL), and TMSOTf (0.12 mL, 0.707 mmol) was added to the solution. The reaction mixture was placed in a preheated oil bath at 80 ° C and stirred. After 3 hours, the reaction mixture was cooled to room temperature and the solvent was removed under reduced pressure. The resulting solid was dissolved in ethyl acetate (80 mL), and the solution was mixed with saturated NaHCO 3 The organic phase was separated and the mixture was stirred with Na 2 SO 4 Dry and concentrate. 2 , 0-60% ethyl acetate-petroleum-ether) to purify the crude compound to give ((2S,4R,5R)-5-(2-acetamido-7-benzyl-6,8-dioxo-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate (100 mg, 17%) as an off-white solid;

[0555] ES+,m / z 262.2[M+H] + ; C 28 H 27 N 5 O 8 .

[0556] Step-5: 2-Amino-7-benzyl-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 33

[0557] To a solution of ((2S,4R,5R)-5-(2-acetamido-7-benzyl-6,8-dioxo-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate (0.1 g, 0.178 mmol) in methanol (5 mL) was added K 2 CO 3(122.9 mg, 0.891 mmol), the reaction mixture was stirred at room temperature for 16 hours. The reaction progress was monitored by LC-MS. After the starting material was completely consumed, the reaction mixture was concentrated under reduced pressure. The crude product was purified by Grace flash chromatography using methanol and dichloromethane, and 92% of 40 mg product was obtained by LC-MS. The compound was further dissolved in 1 mL of methanol and stirred for 20 minutes. The precipitated compound was collected by filtration and dried to obtain 2-amino-7-benzyl-9-((2R, 3R, 5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, compound 33 (15 mg, 22%), as an off-white solid. ES+, m / z 374.2[M+H] + ; C 17 H 19 N 5 O5; 1 H NMR (500 MHz, DMSO-d 6 ): δ10.97(s,1H),7.32–7.31(s,5H),6.52(s,2H),5.52(d,J=5Hz,1H),5.35(d,J=5Hz,1H),4.98(s,2H),4.82–4.78(m 1H), 4.69 (t, J = 10Hz, 1H), 4.14–412 (m, 1H), 3.48–3.41 (m, 2H), 2.37–2.32 (m, 1H), 1.84–1.79 (m, 1H).

[0558] Embodiment 34: 2-amino-7-(3-fluorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 34

[0559]

[0560] Using the same general procedure as described in Example 5A, compound 34 was also synthesized according to the following multi-step procedure.

[0561]

[0562] Step-1: 2-Amino-6-(benzyloxy)-7-(3-fluorobenzyl)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (54)

[0563] 3-Fluorobenzyl bromide (0.75 ml, 5.96 mmol) was added to 2-amino-6-(benzyloxy)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (2 g, 5.305 mmol) and K at 0°C. 2 CO 3 (1.64 g, 11.93 mmol) in a suspension of DMF (20 mL) and stirred at room temperature for 18 h. The reaction mixture was quenched with ice water (120 mL), diluted with ether (80 mL) and stirred for 15 minutes. The precipitated solid was filtered, washed with water and dried to give an off-white solid 2-amino-6-(benzyloxy)-7-(3-fluorobenzyl)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (1.7 g, 89%); ES+, m / z 486.1 [M+H] + ; C 27 H 24 FN 5 O 3 ; 1 H NMR (400 MHz, DMSO-d 6 ): δ7.31–7.29(m 4H),7.26–7.21(m,4H),7.09–7.04(m 1H),6.93–6.87(m,4H),6.44(s,1H),5.33(s,2H),4.96(s,2H),4.86(s,2H),3.71(s,3H).

[0564] Step-2: 2-Amino-7-(3-fluorobenzyl)-7,9-dihydro-1H-purine-6,8-dione (55)

[0565] Under argon atmosphere, trifluoromethanesulfonic acid (1.85 mL, 21.03 mmol) was added to a suspension of 2-amino-6-(benzyloxy)-7-(3-fluorobenzyl)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (1.7 g, 3.50 mmol) in trifluoroacetic acid (2.09 mL, 21.03 mmol) at 0°C, and the resulting reaction mixture was slowly warmed to room temperature and stirred for 3 hours. The reaction mixture was quenched with ice-cold water and heated with saturated NaHCO under vigorous stirring. 3 The solution was basified and filtered. The residual solid was dissolved in ethyl acetate, stirred for 30 minutes, filtered and dried to give 2-amino-7-(3-fluorobenzyl)-7,9-dihydro-1H-purine-6,8-dione (0.7 g, 72%) as a brown solid; ES+, m / z 276.1 [M+H] + ; C 12 H 10 FN5 O 2 ; 1 H NMR (400 MHz, DMSO-d 6 ): δ11.2(s,1H),10.67(s,1H),7.36–7.33(m,1H),7.13–7.05(m,4H),6.39(s,2H),4.94(s,2H).

[0566] Step-3: N-(7-(3-Fluorobenzyl)-6,8-dioxo-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (56)

[0567] Acetic anhydride (0.76 mL, 7.63 mmol) was added to a solution of 2-amino-7-(3-fluorobenzyl)-7,9-dihydro-1H-purine-6,8-dione (0.7 g, 2.545 mmol) in DMF (10 mL) at ambient temperature and under an argon atmosphere, and the resulting reaction mixture was stirred at 130 ° C for 3 hours under an argon atmosphere. The reaction mixture was cooled to 0 ° C (solid formed under stirring) and stirred for 30 minutes. The product was filtered, washed with ethanol, and dried in vacuo to give N-(7-(3-fluorobenzyl)-6,8-dioxo-6,7,8,9tetrahydro-1H-purine-2-yl)acetamide (600 mg, 75%) as a brown solid. The crude compound was used directly in the next step. ES-, m / z 316.1 [MH] - ; C 14 H 12 FN 5 O 3 ; 1 H NMR (400 MHz, DMSO-d 6 ): δ12.02(s,1H),11.80(s,1H),11.66(s,1H),7.38–7.34(m,1H),7.16–7.07(m,4H),5.02(s,2H),2.14(s,3H).

[0568] Step-4: ((2S,4R,5R)-5-(2-acetamido-7-(3-fluorobenzyl)-6,8-dioxo-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate (57)

[0569] N-(7-3-Fluorobenzyl)-6,8-dioxo-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (440 mg, 1.338 mmol), (3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester (536 mg, 1.66 mmol), and BSA (1.0 mL, 4.16 mmol) were dissolved in 1,2-dichloromethane (10 mL), and the resulting reaction mixture was stirred at 80 ° C for 30 minutes under argon. The reaction mixture was concentrated under reduced pressure, the residue was diluted with anhydrous acetonitrile (10 mL), and TMSOTf (0.17 mL, 0.97 mmol) was added. The reaction mixture was placed in a preheated oil bath at 80 ° C and stirred. After 3 hours, the reaction mixture was cooled to room temperature, and the solvent was removed under reduced pressure. The resulting solid was dissolved in ethyl acetate (80 mL), and the solution was mixed with saturated NaHCO 3 The organic phase was separated and the mixture was stirred with Na 2 SO 4 The crude compound was purified by column chromatography (SiO2, 0-60% ethyl acetate-petroleum-ether) to give ((2S,4R,5R)-5-(2-acetamido-7-(3-fluorobenzyl)-6,8-dioxo-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate (150 mg, 18%) as an off-white solid; ES+, m / z 580.1 [M+H] + ; C 28 H 26 FN 5 O 8 ; 1 H NMR (400 MHz, DMSO-d 6 ): δ12.1(s,1H),11.55(s,1H),7.88(d,J=8Hz,2H),7.64–7.60(m,2H),7.44(t,J=8Hz,3H),7.16–7.07(m,3H),5. 76–5.72(m,2H),5.05(S,2H),4.51(d,J=8Hz,2H),4.40–4.36(m,1H),3.16(d,J=4,1H),2.17(s,3H),2.15(s,3H).

[0570] Step-5: 2-amino-7-(3-fluorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 34

[0571] To a solution of ((2S,4R,5R)-5-(2-acetamido-7-(3-fluorobenzyl)-6,8-dioxo-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate (150 mg, 0.259 mmol) in methanol (5 mL) was added K 2 CO 3 (177.4mg, 1.295mmol), the reaction mixture was stirred at room temperature for 16 hours. The reaction progress was monitored by LC-MS. After the reaction was completed, the solvent was removed under reduced pressure. The crude compound was purified by GRACE flash chromatography using methanol and dichloromethane to obtain 50mg product. LC-MS showed 75% product. The impure product was dissolved in 1mL methanol, stirred for 20 minutes, then filtered and dried to give 2-amino-7-(3-fluorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 34) (16mg, 22%) as an off-white solid; ES+, m / z 392.1[M+H] + ; C 17 H 18 FN 5 O 5 ; 1 H NMR (500 MHz, DMSO-d 6 ): δ10.87(s,1H),7.39–7.35(m,1H),7.15–7.08(m,3H),6.52(s,2H),5.52(d,J=5Hz,1H),5.36(d,J=5Hz,1H),4.99(s,2 H),4.82–4.79(s,1H),4.67(t,J=10Hz,1H),4.15–4.11(m,1H),3.48–3.39(m,2H),2.36–2.32(m,1H),1.84–1.80(m,1H).

[0572] Embodiment 35: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4-(trifluoromethyl)benzyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 35

[0573]

[0574] Using the same general procedure as described in Example 5A, compound 35 was also synthesized according to the following multi-step method.

[0575]

[0576] Step-1: 2-Amino-6-(benzyloxy)-9-(4-methoxybenzyl)-7-(4-(trifluoromethyl)benzyl)-7,9-dihydro-8H-purin-8-one (58)

[0577] 1-(Bromomethyl)-4-(trifluoromethyl)benzene (2.28 g, 9.54 mmol) was added to 2-amino-6-(benzyloxy)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (3 g, 7.95 mmol) and K at 0°C. 2 CO 3 (1.64 g, 11.93 mmol) in a suspension of DMF (30 mL) and stirred at room temperature for 16 h. The reaction mixture was quenched with ice water (120 mL), diluted with ether (80 mL) and stirred for 15 minutes. The resulting precipitate was collected by filtration, washed with water and dried to give 2-amino-6-(benzyloxy)-9-(4-methoxybenzyl)-7-(4-(trifluoromethyl)benzyl)-7,9-dihydro-8H-purin-8-one (3.8 g, 90%) as an off-white solid; ES+, m / z 536.2 [M+H] + ; C 28 H 2 4F 3 N 5 O 3 ; 1 HNMR (400 MHz, DMSO-d 6 ): δ7.60(d,J=8.4Hz,2H),7.31–7.21(m,7H),7.16(d,J=6.4Hz,2H),6.89(d,J =8.8Hz,2H),6.45(s,2H),5.31(s,2H),5.04(s,2H),4.87(s,2H),3.71(s,3H).

[0578] Step-2: 2-Amino-7-(4-(trifluoromethyl)benzyl)-7,9-dihydro-1H-purine-6,8-dione (59)

[0579] Under argon atmosphere, trifluoromethanesulfonic acid (1.97 mL, 22.42 mmol) was added to a suspension of 2-amino-6-(benzyloxy)-9-(4-methoxybenzyl)-7-(4-(trifluoromethyl)benzyl)-7,9-dihydro-8H-purin-8-one (2 g, 3.73 mmol) in trifluoroacetic acid (1.7 mL, 3.73 mmol) at 0°C, and the resulting reaction mixture was slowly warmed to room temperature and stirred for 3 hours. The reaction mixture was quenched with ice-cold water and heated with saturated NaHCO under vigorous stirring. 3The solution was basified and filtered. The residual solid was placed in ether (100 mL), stirred for 30 minutes, filtered and dried to give 2-amino-7-(4-(trifluoromethyl)benzyl)-7,9-dihydro-1H-purine-6,8-dione (1 g; 83%) as an off-white solid: ES+, m / z 326.1 [M+H] + ; C 13 H 10 F 3 N 5 O 2 : 1 H NMR (400 MHz, DMSO-d 6 ): δ11.24(s,1H),10.67(s,1H),7.69(d,J=8.4Hz,2H),7.48(d,J=8Hz,2H),6.40(s,2H),5.02(s,2H).

[0580] Step-3: N-(6,8-Dioxo-7-(4-(trifluoromethyl)benzyl)-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (60)

[0581] Acetic anhydride (2 mL) was added to a solution of 2-amino-7-(4-(trifluoromethyl)benzyl)-7,9-dihydro-1H-purine-6,8-dione (1.4 g, 4.30 mmol) in DMF (20 mL) at ambient temperature under argon atmosphere, and the resulting reaction mixture was heated at 140° C. for 3 hours. The reaction mixture was cooled to 0° C. with stirring, whereupon a solid formed. Stirring was continued for 30 minutes, the product was filtered, and dried in vacuo to afford N-(6,8-dioxo-7-(4-(trifluoromethyl)benzyl)-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (1 g, 63%) as an off-white solid: ES+, m / z 368.1 [M+H] + ; C 15 H 12 F 3 N 5 O 3 : 1 HNMR (400 MHz, DMSO-d 6 ): δ12.36(s,1H),11.44(s,1H),7.70(d,J=8Hz,2H),7.57(d,J=8.4Hz,2H),6.98(br s,1H),5.19(s,2H),2.17(s,3H).

[0582] Step-4:((2S,4R,5R)-5-(2-acetamido-6,8-dioxo-7-(4-(trifluoromethyl)benzyl)-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate (61)

[0583] N-(6,8-dioxo-7-(4-(trifluoromethyl)benzyl)-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (350 mg, 0.953 mmol), (3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester (368 mg, 1.143 mmol), and BSA (0.72 mL, 2.859 mmol) were dissolved in 1,2-dichloroethane (10 mL), and the resulting reaction mixture was stirred at 80° C. for 30 minutes under argon. The reaction mixture was cooled to room temperature, and TMSOTf (0.12 mL, 0.667 mmol) was added. The reaction mixture was maintained at 80° C. for 3 hours, then cooled to room temperature, diluted with water and washed with CH 2 Cl 2 The combined organic layers were washed with water (100 mL), brine (100 mL), and purified by Na 2 SO 4 Dry and concentrate under reduced pressure. 2 , 0-60% EtOAc-petroleum-ether) to purify the crude compound to give ((2S,4R,5R)-5-(2-acetamido-6,8-dioxo-7-(4-(trifluoromethyl)benzyl)-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate (70 mg, 11%) as an off-white solid: C 29 H 26 F 3 N 5 O 8 :LC-MS showed 84% of expected mass; ES+, m / z 368.1[M+H] + .

[0584] Step-5: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4-(trifluoromethyl)benzyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 35

[0585] To a solution of ((2S,4R,5R)-5-(2-acetamido-6,8-dioxo-7-(4-(trifluoromethyl)benzyl)-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate (70 mg, 0.111 mmol) in methanol (5 mL) was added K 2 CO 3 (61 mg, 0.445 mmol), the reaction mixture was stirred at room temperature for 16 hours. The reaction mixture was directly purified by RP flash chromatography, and the prepared fractions were lyophilized to give compound 2-amino-9-((2R, 3R, 5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4-(trifluoromethyl)benzyl)-7,9-dihydro-1H-purine-6,8-dione (Compound 35) as a white solid (25 mg, 51%); ES+, m / z 442.1 [M+H] + ; C 18 H 18 F 3 N 5 O 5 : 1 H NMR (500 MHz, DMSO-d 6 ): δ10.95(s,1H),7.70(d,J=8.5Hz,2H),7.51(d,J=8Hz,2H),6.58(s,2H),5.54(d,J=3Hz,1H),5.37(d,J=4.5Hz,1H),5.07 (s,2H),4.82–4.80(m,1H),4.69–4.67(m,1H),4.15–4.13(m,1H),3.47–3.40(s,2H),2.38–2.32(m,1H),1.84–1.80(m,1H).

[0586] Embodiment 36: 7-allyl-2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 36

[0587]

[0588] Using the same general procedure as described in Example 5A, compound 36 was also synthesized according to the following multi-step procedure.

[0589]

[0590] Step-1: 7-allyl-2-amino-6-(benzyloxy)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (62)

[0591] Allyl bromide (0.767 g, 5.30 mmol) was added to 2-amino-6-(benzyloxy)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (2 g, 5.298 mmol) and K at 0°C. 2 CO 3 (1.09 g, 7.95 mmol) in a suspension of DMF (20 mL) and stirred at room temperature for 18 h. The reaction mixture was quenched with ice water (120 mL), diluted with ether (80 mL) and stirred for 15 minutes. The resulting precipitated solid was collected by filtration, washed with water and dried to give 7-allyl-2-amino-6-(benzyloxy)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (2.0 g, 76%) as an off-white solid; ES+, m / z 418.1 [M+H] + ; C 23 H 23 N 5 O 3 ; 1 H NMR (400 MHz, DMSO-d 6 ): δ7.44(d,J=7.5Hz,2H),7.40–7.36(m,2H),7.30(d,J=4.5Hz,1H),7.21(d,J=8.5Hz,2H),6.8(d,J=8.5Hz,2H),6.40(s,2H ),5.89–5.82(m,1H),5.37(s,2H),5.05(d,J=10Hz,1H),5.04(d,J=15Hz,1H),4.83(s,2H),4.37(d,J=5Hz,2H),3.71(s,3H).

[0592] Step-2: 7-Allyl-2-amino-7,9-dihydro-1H-purine-6,8-dione (63)

[0593] Under argon atmosphere, trifluoromethanesulfonic acid (1.268 mL, 14.37 mmol) was added to a suspension of 7-allyl-2-amino-6-(benzyloxy)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (2 g, 4.79 mmol) in trifluoroacetic acid (1.09 mL, 14.37 mmol) at 0°C, and the resulting reaction mixture was slowly warmed to room temperature and stirred for 3 hours. The reaction mixture was quenched with ice-cold water and heated with saturated NaHCO under vigorous stirring. 3The solution was basified and filtered. The residual solid was dissolved in ethyl acetate, stirred for 30 minutes and filtered; the residue was dried to give 7-allyl-2-amino-7,9-dihydro-1H-purine-6,8-dione (0.54 g, 56%) as a brown solid. ES+, m / z 208.1 [M+H] + ; C 8 H 9 N 5 O 2 ; 1 H NMR (400 MHz, DMSO-d 6 ): 1 H NMR (500 MHz, DMSO-d 6 ;

[0594] Step-3: N-(7-allyl-6,8-dioxo-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (64)

[0595] Acetic anhydride (0.74 mL) was added to a solution of 7-allyl-2-amino-7,9-dihydro-1H-purine-6,8-dione (0.54 g, 7.82 mmol) in DMF (5 mL) at ambient temperature and under an argon atmosphere, and the resulting reaction mixture was heated at 130 ° C for 3 hours under an argon atmosphere. The reaction mixture was cooled to 0 ° C and a solid was formed under stirring after 30 minutes. The product was collected by filtration, washed with ethanol, and dried in vacuo to give N-(7-allyl-6,8-dioxo-6,7,8,9-tetrahydro-1H-purine-2-yl)acetamide (0.50 g, 61%) as a brown solid. The crude compound was used directly in the next step. ES+, m / z 250.1 [M+H] + ; C 10 H 11 N 5 O 3 ; 1 H NMR (400 MHz, DMSO-d 6 ): δ11.99(s,1H),11.74(s,1H),11.67(s,1H),5.96–5.87(m,1H),5.10(d ,J=1.6Hz,1H),5.04(d,J=1.6Hz,1H),4.4(d,J=5.6Hz,2H),2.19(s,3H).

[0596] Step-4: ((2S,4R,5R)-5-(2-Acetamido-7-allyl-6,8-dioxo-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate (65)

[0597] N-(7-allyl-6,8-dioxo-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (500 mg, 2.01 mmol), (3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester (969 mg, 3.01 mmol), BSA (1.47 mL, 6.08 mmol) were dissolved in ACN (10 mL). The resulting reaction mixture was stirred at 80 ° C for 30 minutes under argon. The reaction mixture was concentrated under reduced pressure, the residue was diluted with anhydrous acetonitrile (9.5 mL, 1.40 mmol), and TMSOTf (0.254 mL, 1.40 mmol) was added. The reaction mixture was placed in a preheated oil bath at 80 ° C and stirred. After 3 hours, the reaction mixture was cooled to room temperature and the solvent was removed under reduced pressure. The resulting solid was dissolved in ethyl acetate (80 mL), and the solution was mixed with saturated NaHCO 3 The aqueous solution (2×30 mL) was shaken together. The organic phase was separated and the 2 SO 4 Dry and concentrate. 2 , 0-60% EtOAc-petroleum-ether) to give ((2S,4R,5R)-5-(2-acetamido-7-allyl-6,8-dioxo-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate (180 mg, 24%) as an off-white solid. 1 H NMR (500 MHz, DMSO-d 6 ): δ12.1(s,1H),11.51(s,1H),7.90(d,J=10Hz,2H),7.65–7.61(m,1H),7.46(t,J=8.5Hz,2H),5.87–5.75(m,1H),5.75–5.72(m,2H), 5.11–5.01(m,2H),4.53(d,J=5Hz,2H),4.46(d,J=2.5Hz,2H),4.40–4.36(m,1H),2.92(m,1H),2.14(s,3H),2.10(m,1H),2.08(s,3H).

[0598] Step-5:7-allyl-2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 36

[0599] A solution of ((2S,4R,5R)-5-(2-acetamido-7-allyl-6,8-dioxo-1,6,7,8-tetrahydro-9H-purine-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate (180 mg, 0.352 mmol) obtained in a sealed container in 7M ammonia in methanol (5 mL) was stirred at room temperature. The progress of the reaction was monitored by LC-MS. After complete consumption of the starting material, the reaction mixture was concentrated under reduced pressure. The resulting thick solid was dissolved in a minimum amount of methanol, and ether (10 mL) was added, stirred for 30 minutes and filtered. After drying, 7-allyl-2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 36) (60 mg, 51%) was isolated as an off-white solid. ES+,m / z324.1[M+H] + ; C 13 H 17 N 5 O 5 ; 1 H NMR (500 MHz, DMSO-d 6 ): δ10.91(s,1H),6.51(s,2H),5.90(m,1H),5.53(d,J=2.5Hz,1H),5.37(d,J=4Hz,1H),5.06(dd,J=10Hz, 2H),4.72(bs,2H),4.39(d,J=4Hz,2H),4.14(s,1H),3.44(m,2H),2.35(m,1H),1.82(m,1H).mp=199-203℃.

[0600] Embodiment 37: 2-Amino-7-butyl-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 37

[0601]

[0602] Using the same general procedure as described in Example 5A, compound 37 was also synthesized according to the following multi-step procedure.

[0603]

[0604] Step-1:2-Amino-6-(benzyloxy)-7-butyl-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (66)

[0605] Butyl bromide (0.43 ml, 3.183 mmol) was added to 2-amino-6-(benzyloxy)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (1 g, 2.65 mmol) and K at 0°C. 2 CO 3 (0.548 g, 3.97 mmol) in a suspension of DMF (10 mL) and stirred at room temperature for 18 h. The reaction mixture was quenched with ice water (120 mL), diluted with ether (80 mL) and stirred for 15 minutes. The resulting precipitated solid was collected by filtration, washed with water and dried to give a brown solid 2-amino-6-(benzyloxy)-7-butyl-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (0.80 g, 69%); ES+, m / z 433.1 [M+H] + ; C 24 H 27 N 5 O 3 ; 1 H NMR (400 MHz, DMSO-d 6 ): δ7.4(d,J=6.8Hz,2H),7.34–7.41(m,3H),7.20(d,J=8Hz,2H),6.8(d,J=8.8Hz,2H),6.4(s,2H),5.4(s, 2H), 4.8 (s, 2H), 3.7 (t, J = 15.6Hz, 5H), 1.5 (t, J = 14.4Hz, 2H), 1.11–1.17 (m, 2H), 0.76 (t, J = 14.8Hz, 3H).

[0606] Step-2: 2-Amino-7-butyl-7,9-dihydro-1H-purine-6,8-dione (67)

[0607] Under argon atmosphere, trifluoromethanesulfonic acid (1.03 g, 6.89 mmol) was added to a suspension of 2-amino-6-(benzyloxy)-7-butyl-9-(4-methoxybenzyl)-7,9-dihydro-8H-purine-8-one (1.0 g, 2.30 mmol) in trifluoroacetic acid (0.786 mL, 6.89 mmol) at 0 ° C. The reaction mixture was slowly warmed to room temperature and stirred for 3 hours. The reaction mixture was quenched with ice-cold water and saturated NaHCO was added under vigorous stirring. 3The solid was filtered, dissolved in ethyl acetate, stirred for 30 minutes, filtered and dried to give 2-amino-7-butyl-7,9-dihydro-1H-purine-6,8-dione (0.30 g, 58%) as a brown solid. ES+, m / z 224.1 [M+H] + ; C 9 H 13 N 5 O 2 ; 1 H NMR (400 MHz, DMSO-d 6 ): δ11.0(s,1H),10.6(s,1H),6.3(s,2H),3.7(t,J=16Hz,2H),1.5–1.6(m,2H),1.25–1.20(m,2H),0.8(t,J=12Hz,3H).

[0608] Step-3: N-(7-butyl-6,8-dioxo-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (68) and N-acetyl-N-(7-butyl-6,8-dioxo-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (68a)

[0609] Acetic anhydride (0.20 ml, 2.01 mmol) was added to a DMF (5 mL) solution of 2-amino-7-butyl-7,9-dihydro-1H-purine-6,8-dione (0.300 g, 1.345 mmol) at ambient temperature under an argon atmosphere. The resulting reaction mixture was stirred at 130 ° C for 3 h under an argon atmosphere. The reaction mixture was cooled to 0 ° C (solid formed under stirring) and stirred for 30 minutes. The product was filtered, washed with ethanol and dried in vacuo to give a mixture of N-(7-butyl-6,8-dioxo-6,7,8,9-tetrahydro-1H-purine-2-yl)acetamide (68) and N-acetyl-N-(7-butyl-6,8-dioxo-6,7,8,9-tetrahydro-1H-purine-2-yl)acetamide (68a) (0.150 g, 42%) as a brown solid. LC-MS showed 20% of (68); ES+, m / z 266.1 [M+H] + ; C 11 H 15 N 5 O 3 ; and 49% of (68a); ES+, m / z 308.1[M+H] + ; C 13 H 17 N 5 O 4 ; The mixture was used directly in the next step.

[0610] Step-4: ((2S,4R,5R)-5-(2-acetamido-7-butyl-6,8-dioxo-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate (69)

[0611] A mixture of N-(7-butyl-6,8-dioxo-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (68) and N-acetyl-N-(7-butyl-6,8-dioxo-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (68a) (1.433 mmol), (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester (0.692 g, 2.150 mmol) and BSA (0.58 g, 2.86 mmol) were dissolved in dichloroethane (9.5 mL) and stirred at 80° C. for 30 minutes under argon. The reaction mixture was concentrated under reduced pressure, the residue was diluted with anhydrous acetonitrile (9.5 mL), and TMSOTf (0.2 g, 0.931 mmol) was added. The reaction mixture was placed in a preheated oil bath at 80°C and stirred. After 3 hours, the reaction mixture was cooled to room temperature and the solvent was removed under reduced pressure. The resulting solid was dissolved in ethyl acetate (80 mL) and the solution was mixed with saturated NaHCO 3 The aqueous solution (2×30 mL) was shaken together. 2 SO 4 The organic phase was dried and concentrated. The crude compound was purified by column chromatography (SiO 2 , 0-60% EtOAc-petroleum ether as eluent) to give 200 mg (26%) of ((2S,4R,5R)-5-(2-acetamido-7-butyl-6,8-dioxo-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate as a light yellow solid (purity 78% by LC / MS); ES+, m / z 528.2 [M+H] + ; C 25 H 29 N 5 O 8 .

[0612] Step-5: 2-Amino-7-butyl-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 37

[0613] ((2S,4R,5R)-5-(2-acetamido-7-butyl-6,8-dioxo-1,6,7,8-tetrahydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl benzoate (0.150 g, 0.285 mmol) was dissolved in methanolic ammonia (10 mL), and the reaction mixture was stirred at room temperature for 18 h. The reaction mixture was concentrated under reduced pressure. The crude product was purified by GRACE reverse phase purification system (MeCN-0.01% HCO 2 H of H 2 O solution as eluent) to give 0.060 g (62%) of 2-amino-7-butyl-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 37) as a white solid. ES+, m / z 340.2 [M+H] + ,C 14 H 21 N 5 O 5 ; 1 H NMR (400 MHz, DMSO-d 6 ): δ10.87(s,1H),6.4(s,2H),5.5(d,J=4Hz,1H),5.3(d,J=4Hz,1H),4.70–4.8(m,1H),4.7(t,J=12Hz,1H),4.1(t,J=12Hz,1 H),3.7(t,J=16Hz,2H),3.3–3.4(m,2H),2.3–2.5(m,1H),1.7–1.8(m,1H),1.5–1.6(m,2H),1.21–1.27(m,2H),0.8(t,J=16Hz 3H).

[0614] Preparation of intermediates (70), (71), (72), (73) and (74)

[0615] Intermediate compounds (70-74) were synthesized according to the following multi-step process.

[0616]

[0617] Step-1: 2-Amino-6-chloro-7-(cyclopropylmethyl)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (70)

[0618] Cyclopropylmethyl bromide (32.9 g, 24.39 mol) was added to 2-amino-6-chloro-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (36) (62 g, 20.32 mol), K 2 CO3 (42g, 30.49mol) in DMF (500mL) suspension, then stirred at room temperature for 18 hours. The reaction mixture was poured into ice-cold water and stirred at room temperature for 30 minutes. The precipitated solid product was collected by filtration and dried under vacuum to give a brown solid 2-amino-6-chloro-7-(cyclopropylmethyl)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (70) (60g, 82%). TLC: 30% ethyl acetate in hexane; R f :0.4; ES+, m / z 360.1[M+H] + ; C 17 H 18 C1N 5 O 2 ; 1 H NMR (400 MHz, DMSO-d 6 ): δ7.23(d,J=8.4Hz,2H),6.89(d,J=8.8Hz,2H),6.75(s,2H),4.86(s,2H),3.80(d, J=6.8Hz,2H),3.71(s,3H),1.21-1.17(m,1H),0.50-0.46(m,2H),0.37-0.34(m,2H).

[0619] Step-2: 2-Amino-7-(cyclopropylmethyl)-7,9-dihydro-8H-purin-8-one (71)

[0620] 10% Pd-C (5.0 g) was added to a suspension of 2-amino-6-chloro-7-(cyclopropylmethyl)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purine-8-one (70) (20 g, mmol) in methanol (500 mL). The reaction mixture was hydrogenated with hydrogen at a pressure of 80 psi in a Parr shaker bottle at room temperature for 24 hours. The reaction mixture was filtered through a celite pad and the filtrate was evaporated to give a crude product. Acetonitrile was added to the crude compound, stirred for 15 minutes and filtered. This step was repeated and the solid was dried in vacuo to give 2-amino-7-(cyclopropylmethyl)-7,9-dihydro-8H-purine-8-one (71) (11 g, 64%) as an off-white solid. TLC: 70% ethyl acetate in hexane; R f :0.2; ES+, m / z 206.2[M+H] + ; C 9 H 11 N 5 O. 1 HNMR (500 MHz, DMSO-d 6): δ12.68(s,1H),8.11(s,1H),7.87(s,2H),3.60–3.59(d,J=7.5Hz,2H),1.18–1.12(m,1H),0.50-0.46(m,2H),0.37-0.34(m,2H).mp245-249℃.

[0621] Step-3: 2-Amino-6-chloro-7-(cyclopropylmethyl)-7,9-dihydro-8H-purin-8-one (72)

[0622] Anhydrous AlCl 3 The powder (25 g, 187 mmol) was added to a stirred solution of 2-amino-6-chloro-7-(cyclopropylmethyl)-9-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one (70) (50 g, 139.2 mmol) in 1,2-dichlorobenzene (250 mL), and the resulting reaction mixture was stirred at 100 ° C. for 18 hours under argon atmosphere. The reaction mixture was cooled to room temperature and quenched with ice-cold water and heated with saturated NaHCO under vigorous stirring. 3 The solution was alkalized and filtered. The filtered solid was dissolved in 10% MeOH in dichloromethane, stirred for 30 minutes and filtered (repeated three times with a volume of 1.0 L solvent). The filtrate was passed through a diatomaceous earth plate and concentrated under reduced pressure. The solid thus obtained was washed twice with 10% methanol in dichloromethane and filtered. The filtered solid was washed again twice with acetonitrile, filtered and dried to give a brown solid 2-amino-6-chloro-7-(cyclopropylmethyl)-7,9-dihydro-8H-purine-8-one (72) (12 g, 36%). TLC: 50% ethyl acetate in hexane; R f :0.3; ES+, m / z 240.1[M+H] + ; C 9 H 10 C1N 5 O. 1 H NMR (500 MHz, DMSO-d 6 ): δ11.81(s,1H),6.58(s,2H),3.73-3.72(d,J=7.0Hz,2H),1.21-1.17(m,1H),0.50-0.46(m,2H),0.37-0.34(m,2H).mp286-290℃.

[0623] Step-4: 2-Amino-6-(benzyloxy)-7-(cyclopropylmethyl)-7,9-dihydro-8H-purin-8-one (73)

[0624] Sodium metal (1.43 g, 62.6 mmol) was added to benzyl alcohol (25.0 mL) for 1 hour (until all sodium was dissolved). The resulting viscous liquid was cooled to room temperature, and 2-amino-6-chloro-7-(cyclopropylmethyl)-7,9-dihydro-8H-purine-8-one (72) (5.0 g, 20.86 mmol) was added. The resulting reaction mixture was stirred at 100 ° C for 1 h and quenched with ice water (200 mL). Ether (150 mL) was added and stirred for 15 minutes. The precipitated solid was filtered, washed with water and dried. The solid was dissolved in 15% methanol-dichloromethane (500 mL), filtered through a diatomaceous earth pad, washed with brine and concentrated. The resulting solid was washed with ether and filtered to give an off-white solid 2-amino-6-(benzyloxy)-7-(cyclopropylmethyl)-7,9-dihydro-8H-purine-8-one (73) (3.5 g, 54%). TLC: 70% ethyl acetate in petroleum ether; R f :0.6; ES+, m / z 312.2[M+H] + ; C 16 H 17 N 5 O 2 . 1 H NMR (500 MHz, DMSO-d 6 ): δ11.30(brs,1H),7.48-7.46(m,2H),7.41-7.38(m,2H),7.35–7.30(m,1H),6.15(s,2H),5.41(s ,2H),3.56(d,J=7.0Hz,2H),1.14-1.10(m,1H),0.36-0.32(m,2H),0.23-0.21(m,2H).mp238-242℃.

[0625] Step-5: 2-Amino-7-(cyclopropylmethyl)-7,9-dihydro-1H-purine-6,8-dione (74)

[0626] A suspension of 2-amino-6-(benzyloxy)-7-(cyclopropylmethyl)-7,9-dihydro-8H-purin-8-one (73) (10.0 g, 32.15 mmol), anhydrous LiBr (3.34 g, 38.58 mmol), and chlorotrimethylsilane (4.53 g, 108.6 mmol) in acetonitrile (700 mL) was stirred at room temperature for 16 h. Methanol (60 mL) was added to the reaction mixture and stirred for 30 min. The solvent was evaporated to reduce the volume to about 100 mL and filtered. The filter cake was washed with acetonitrile and dried. The solid was dissolved in saturated NaHCO 3The solution was stirred for 1 h, filtered, washed with water and dried. The solid was stirred in 10% methanol / dichloromethane (50 mL), filtered and dried to give a light brown solid 2-amino-7-(cyclopropylmethyl)-7,9-dihydro-1H-purine-6,8-dione (74) (8.5 g, 80%). TLC: 10% methanol in dichloromethane; R f :0.4; ES+, m / z 222.1 [M+H] + ; C 9 H 11 N 5 O 2 . 1 HNMR (500 MHz, DMSO-d 6 ): δ11.06(s,1H),10.68(s,1H),6.36(s,2H),3.58(d,J=7.0Hz,2H),1.19-1.14(m,1H),0.40-0.36(m,2H),0.33-0.30(m,2H).mp364-368℃.

[0627] Example 31S :((2R,3S,4S,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate (Compound 31S)

[0628] Compound 31S can be prepared using the method described in Example 31, substituting (23) for (18).

[0629] Example 32S :2-amino-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one (Compound 32S)

[0630] Compound 32S can be prepared using the method described in Example 32 from compound 31S.

[0631] Embodiment 38: 2-amino-7-(4-fluorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 38

[0632] Compound 38 can be prepared according to the method in Example 26 or Examples 5A and 26A together with 4-fluorobenzyl bromide.

[0633] Embodiment 39:2-Amino-7-(3,4-difluorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 39

[0634] Compound 39 can be prepared according to the method in Example 26 or Examples 5A and 26A together with 3,4-difluorobenzyl bromide.

[0635] Embodiment 40: 2-Amino-7-(4-chlorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 40

[0636] Compound 40 can be prepared according to the method in Example 26 or Examples 5A and 26A together with 4-chlorobenzyl bromide.

[0637] Embodiment 41: 2-Amino-7-(3-chlorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 41

[0638] Compound 41 can be prepared according to the method in Example 26 or Examples 5A and 26A together with 3-chlorobenzyl bromide.

[0639] Embodiment 42: 2-Amino-7-(3,4-dichlorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 42

[0640] Compound 42 can be prepared according to the method of Example 26 or Examples 5A and 26A together with 3,4-dichlorobenzyl bromide.

[0641] Embodiment 43: 4-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzonitrile, Compound 43

[0642] Compound 43 can be prepared according to the method of Example 26 or Examples 5A and 26A together with 4-cyanobenzyl bromide.

[0643] Embodiment 44:3-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzonitrile, Compound 44

[0644] Compound 44 can be prepared according to the method of Example 26 or Examples 5A and 26A together with 3-cyanobenzyl bromide.

[0645] Embodiment 45: Methyl 4-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzoate, Compound 45

[0646] Compound 45 can be prepared according to the method in Example 26 or Examples 5A and 26A together with methyl 4-(bromomethyl)benzoate.

[0647] Embodiment 46: 4-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzoic acid, Compound 46

[0648] Compound 46 can be prepared by ester hydrolysis of compound 45.

[0649] Embodiment 47: Methyl 3-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzoate, Compound 47

[0650] Compound 47 can be prepared according to the method of Example 26 or Examples 5A and 26A together with methyl 3-(bromomethyl)benzoate.

[0651] Embodiment 48: 3-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzoic acid, Compound 48

[0652] Compound 48 can be prepared by ester hydrolysis of compound 47.

[0653] Embodiment 49:Methyl 2-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzoate, Compound 49

[0654] Compound 49 can be prepared according to the method in Example 26 or Examples 5A and 26A together with methyl 2-(bromomethyl)benzoate.

[0655] Embodiment 50: 2-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzoic acid, Compound 50

[0656] Compound 50 can be prepared by ester hydrolysis of compound 49.

[0657] Embodiment 51: 2-Amino-7-(E)-cinnamyl-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 51

[0658] Compound 51 can be prepared according to the method of Example 26 or Examples 5A and 26A together with (E)-cinnamyl bromide.

[0659] Embodiment 52: 7-((1H-pyrazol-5-yl)methyl)-2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 52

[0660] Compound 52 can be prepared according to the method in Example 26 or Examples 5A and 26A together with tert-butyl 5-(bromomethyl)-1H-pyrazole-1-carboxylate [1001096-27-0] or 5-(bromomethyl)-1-(4-methoxybenzyl)-1H-pyrazole [1313409-97-0] or the methanesulfonate of (1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazol-5-yl)methanol [1823866-20-1].

[0661] Embodiment 53:2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-((1-methyl-1H-pyrazol-3-yl)methyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 53 Compound 53 can be prepared according to the method in Example 26 or Examples 5A and 26A together with 3-(bromomethyl)-1-methyl-1H-pyrazole [102846-13-9].

[0662] Embodiment 54: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(thiophen-2-ylmethyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 54

[0663] Compound 54 can be prepared according to the method in Example 26 or Examples 5A and 26A together with 2-(bromomethyl)-thiophene.

[0664] Embodiment 55: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(thien-3-ylmethyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 55

[0665] Compound 55 can be prepared according to the method in Example 26 or Examples 5A and 26A together with 3-(bromomethyl)-thiophene.

[0666] Embodiment 56: 2-(2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)acetic acid, Compound 56

[0667] Compound 56 can be prepared according to the method of Example 26 or Examples 5A and 26A using methyl 2-bromoacetate and subsequent ester hydrolysis.

[0668] Embodiment 57: 2-(2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)acetaldehyde, Compound 57

[0669] Compound 57 can be prepared according to the method in Example 26 using 2-bromo-1,1-dimethoxyethane.

[0670] Embodiment 58:2-(2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)acetonitrile, Compound 58

[0671] Compound 58 can be prepared from compound 57 by converting the aldehyde to the corresponding oxime followed by dehydration thereof.

[0672] Embodiment 59: 7-((1H-tetrazolyl-5-yl)methyl)-2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 59

[0673] Compound 59 can be prepared according to the method of Example 26 or Examples 5A and 26A together with 5-(chloromethyl)-1H-tetrazole [55408-11-2].

[0674] Embodiment 60: 2-(2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)-N-(methylsulfonyl)acetamide, Compound 60 Compound 60 can be prepared from Compound 56 and methanesulfonamide.

[0675] Example 61: 2-(2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)-N-hydroxyacetamide, Compound 61

[0676] Compound 61 can be prepared from compound 56 and hydroxylamine.

[0677] Embodiment 62: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-((3-hydroxyisoxazol-5-yl)methyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 62

[0678] Compound 62 can be prepared according to the method of Example 26 or Examples 5A and 26A together with (3-((4-methoxybenzyl)oxy)isoxazol-5-yl)methanol mesylate.

[0679] Embodiment 63:5-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)thiophene-2-carboxylic acid methyl ester, Compound 63

[0680] Compound 63 can be prepared according to the method in Example 26 or Examples 5A and 26A together with methyl 5-(bromomethyl)thiophene-2-carboxylate [108499-32-7].

[0681] Embodiment 64: 5-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)thiophene-2-carboxylic acid, Compound 64

[0682] Compound 64 can be prepared from compound 63 by ester hydrolysis.

[0683] Embodiment 65: 5-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)thiophene-3-carboxylic acid ethyl ester, Compound 65

[0684] Compound 65 can be prepared according to the method in Example 26 or Examples 5A and 26A together with ethyl 5-(bromomethyl)thiophene-3-carboxylate [206860-16-4].

[0685] Embodiment 66: 5-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)thiophene-3-carboxylic acid, Compound 66

[0686] Compound 66 can be prepared from compound 65 by ester hydrolysis.

[0687] Example 67: 4-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)thiophene-2-carboxylic acid methyl ester, Compound 67

[0688] Compound 67 can be prepared according to the method in Example 26 or Examples 5A and 26A together with methyl 4-(bromomethyl)thiophene-2-carboxylate [54796-51-9].

[0689] Embodiment 68: 4-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)thiophene-2-carboxylic acid, Compound 68

[0690] Compound 68 can be prepared from compound 67 by ester hydrolysis.

[0691] Embodiment 69: (1R,2R)-2-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)cyclopropane-1-carboxylic acid, Compound 69

[0692] Compound 69 can be prepared according to the method of Example 26 or Examples 5A and 26A using the mesylate of ethyl (1R,2R)-2-(hydroxymethyl)cyclopropane-1-carboxylate followed by ester hydrolysis.

[0693] Embodiment 70: 7-((E)-3-(1H-tetrazolyl-5-yl)allyl)-2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 70

[0694] Compound 70 can be prepared from compound 36 and 5-vinyl-1H-tetrazole [18755-47-0].

[0695] Embodiment 71: 4-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzaldehyde, Compound 71

[0696] Compound 71 can be prepared according to the method of Example 26 or Examples 5A and 26A together with methyl 4-(bromomethyl)benzaldehyde.

[0697] Embodiment 72: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4-methoxybenzyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 72

[0698] Compound 72 can be prepared according to the method in Example 26 or Examples 5A and 26A together with 4-methoxy-benzyl bromide.

[0699] Embodiment 73:2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(3-methoxybenzyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 73

[0700] Compound 73 can be prepared according to the method in Example 26 or Examples 5A and 26A together with 3-methoxy-benzyl bromide.

[0701] Embodiment 74: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(3-hydroxybenzyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 74

[0702] Compound 74 can be prepared by using BBr 3 Prepared by demethylating compound 73.

[0703] Embodiment 75: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(pyridin-3-ylmethyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 75

[0704] Compound 75 can be prepared according to the method of Example 26 or Examples 5A and 26A together with 3-bromomethylpyridine.

[0705] Embodiment 76: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(2-oxo-2-(pyrrolidin-1-yl)ethyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 76 Compound 76 can be prepared according to the method in Example 26 or Examples 5A and 26A together with bromoacetylpyrrolidine [90892-09-4].

[0706] Embodiment 77: 2-Amino-7-(cyclopropylmethyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 77

[0707] Compound 77 can be prepared by the method of Example 1 using 3'-deoxy-guanosine [3608-58-0] instead of 2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (1) [27462-39-1] or by the method of Example 26A using (74) instead of (40).

[0708] Embodiment 78: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(methoxymethyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 78

[0709] Compound 78 can be prepared according to the method of Example 26 using chloromethyl methyl ether.

[0710] Embodiment 79: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-((methylthio)methyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 79

[0711] Compound 79 can be prepared according to the method in Example 26 using chloromethyl methyl sulfide.

[0712] Embodiment 80: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(2,2,2-trifluoroethyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 80

[0713] Compound 80 can be prepared according to the method in Example 26 or Examples 5A and 26A together with 2-bromo-1,1,1-trifluoroethane [421-06-7].

[0714] Embodiment 81: 2-Amino-7-(2,2-difluoroethyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 81

[0715] Compound 81 can be prepared according to the method in Example 26 or Examples 5A and 26A together with 2-bromo-1,1-difluoroethane [359-07-9].

[0716] Embodiment 82: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(3,3,3-trifluoropropyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 82

[0717] Compound 82 can be prepared according to the method of Example 26 or Examples 5A and 26A together with 3-bromo-1,1,1-trifluoropropane [460-32-2].

[0718] Embodiment 83:2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(2,2,3,3,3-pentafluoropropyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 83

[0719] Compound 83 can be prepared according to the method in Example 26 or Examples 5A and 26A together with 3-bromo-1,1,1,2,2-pentafluoropropane [422-01-5] or 2,2,3,3,3-pentafluoropropyl methanesulfonate [813-31-0].

[0720] Embodiment 84: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4,4,4-trifluorobutyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 84

[0721] Compound 84 can be prepared according to the method of Example 26 or Examples 5A and 26A together with 4-bromo-1,1,1-trifluorobutane [406-81-5].

[0722] Embodiment 85: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(3,3,4,4,4-pentafluorobutyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 85

[0723] Compound 85 can be prepared according to the method of Example 26 or Examples 5A and 26A together with 1,1,1,2,2-pentafluoro-4-bromobutane [52671-70-2].

[0724] Embodiment 86: 3-(2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)propionitrile, Compound 86

[0725] Compound 86 can be prepared according to the method in Example 26 or Examples 5A and 26A together with 3-bromopropionitrile [2417-90-5].

[0726] Embodiment 87: 4-(2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)butanenitrile, Compound 87

[0727] Compound 87 can be prepared according to the method in Example 26 or Examples 5A and 26A together with 4-bromobutyronitrile [5332-06-9].

[0728] Embodiment 88: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-isobutyl-7,9-dihydro-1H-purine-6,8-dione, Compound 88

[0729] Compound 88 can be prepared according to the method of Example 26 or Examples 5A and 26A together with 1-bromo-2-methylpropane.

[0730] Embodiment 89: 1-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)cyclopropane-1-carbonitrile, Compound 89

[0731] Compound 89 can be prepared according to the method of Example 26 or Examples 5A and 26A together with the mesylate of 1-(hydroxymethyl)cyclopropane-1-carbonitrile [98730-77-9].

[0732] Embodiment 90: 1-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)cyclopropane-1-carboxylic acid, Compound 90 Compound 90 can be prepared according to the method in Example 26 or Examples 5A and 26A together with the mesylate of 1-(hydroxymethyl)cyclopropane-1-carboxylic acid ethyl ester [3697-68-5].

[0733] Embodiment 91: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-((1-(trifluoromethyl)cyclopropyl)methyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 91

[0734] Compound 91 can be prepared according to the method in Example 26 or Examples 5A and 26A together with the mesylate of (1-(trifluoromethyl)cyclopropyl)methanol [371917-17-8].

[0735] Embodiment 92: 2-Amino-7-benzyl-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 92

[0736] Compound 92 can be prepared according to the method of Example 27 or Examples 5A and 27A together with benzyl bromide.

[0737] Embodiment 93: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4-fluorobenzyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 93

[0738] Compound 93 can be prepared according to the method in Example 27 or Examples 5A and 27A together with 4-fluorobenzyl bromide.

[0739] Embodiment 94: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(3-fluorobenzyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 94

[0740] Compound 94 can be prepared according to the method of Example 27 or Examples 5A and 27A together with 3-fluorobenzyl bromide.

[0741] Embodiment 95: 2-Amino-7-(3,4-difluorobenzyl)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 95

[0742] Compound 95 can be prepared according to the method in Example 27 or Examples 5A and 27A together with 3,4-difluorobenzyl bromide.

[0743] Embodiment 96: 2-amino-7-(4-chlorobenzyl)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 96

[0744] Compound 96 can be prepared according to the method of Example 27 or Examples 5A and 27A together with 4-chlorobenzyl bromide.

[0745] Embodiment 97: 2-Amino-7-(3-chlorobenzyl)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 97

[0746] Compound 97 can be prepared according to the method of Example 27 or Examples 5A and 27A together with 3-chlorobenzyl bromide.

[0747] Embodiment 98: 2-Amino-7-(3,4-dichlorobenzyl)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 98

[0748] Compound 98 can be prepared according to the method in Example 27 or Examples 5A and 27A together with 3,4-dichlorobenzyl bromide.

[0749] Embodiment 99: 4-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzonitrile, Compound 99

[0750] Compound 99 can be prepared according to the method of Example 27 or Examples 5A and 27A together with 4-cyanobenzyl bromide.

[0751] Embodiment 100: 3-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzonitrile, Compound 100 Compound 100 can be prepared according to the method in Example 27 or Examples 5A and 27A together with 3-cyanobenzyl bromide.

[0752] Embodiment 101: Methyl 4-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzoate, Compound 101

[0753] Compound 101 can be prepared according to the method in Example 27 or Examples 5A and 27A together with methyl 4-(bromomethyl)benzoate.

[0754] Embodiment 102: 4-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzoic acid, Compound 102 Compound 102 can be prepared by ester hydrolysis of Compound 101.

[0755] Embodiment 103:Methyl 3-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzoate, Compound 103

[0756] Compound 103 can be prepared according to the method of Example 27 or Examples 5A and 27A together with methyl 3-(bromomethyl)benzoate.

[0757] Embodiment 104: 3-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzoic acid, Compound 104 Compound 104 can be prepared by ester hydrolysis of Compound 103.

[0758] Embodiment 105: Methyl 2-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzoate, Compound 104

[0759] Compound 104 can be prepared according to the method of Example 27 or Examples 5A and 27A together with methyl 2-(bromomethyl)benzoate.

[0760] Embodiment 105: 2-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzoic acid, Compound 105 Compound 105 can be prepared by ester hydrolysis of Compound 104.

[0761] Embodiment 106: 2-Amino-7-(E)-cinnamyl-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 106

[0762] Compound 106 can be prepared according to the method of Example 27 or Examples 5A and 27A together with (E)-cinnamyl bromide.

[0763] Embodiment 107:7-((1H-pyrazol-5-yl)methyl)-2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 107

[0764] Compound 107 can be prepared according to the method in Example 27 or Examples 5A and 27A together with tert-butyl 5-(bromomethyl)-1H-pyrazole-1-carboxylate [1001096-27-0] or 5-(bromomethyl)-1-(4-methoxybenzyl)-1H-pyrazole [1313409-97-0] or the methanesulfonate of (1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazol-5-yl)methanol [1823866-20-1].

[0765] Embodiment 108: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-((1-methyl-1H-pyrazol-3-yl)methyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 108

[0766] Compound 108 can be prepared according to the method of Example 27 or Examples 5A, 27A and 26A together with 3-(bromomethyl)-1-methyl-1H-pyrazole [102846-13-9].

[0767] Embodiment 109: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(thiophen-2-ylmethyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 109

[0768] Compound 109 can be prepared according to the method in Example 27 or Examples 5A, 27A and 26A together with 2-(bromomethyl)-thiophene.

[0769] Embodiment 110: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(thien-3-ylmethyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 110

[0770] Compound 110 can be prepared according to the method in Example 27 or Examples 5A, 27A and 26A together with 3-(bromomethyl)-thiophene.

[0771] Embodiment 111:2-(2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)acetic acid, Compound 111

[0772] Compound 111 can be prepared according to the method in Example 27 or Examples 5A and 27A and 26A using methyl 2-bromoacetate and subsequent ester hydrolysis.

[0773] Embodiment 112: 2-(2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)acetaldehyde, Compound 112

[0774] Compound 112 can be prepared according to the method of Example 27 using 2-bromo-1,1-dimethoxyethane.

[0775] Embodiment 113: 2-(2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)acetonitrile, Compound 113

[0776] Compound 113 can be prepared from compound 112 by converting the aldehyde to the corresponding oxime followed by dehydration thereof.

[0777] Embodiment 114: 7-((1H-tetrazolyl-5-yl)methyl)-2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 114

[0778] Compound 114 can be prepared according to the method of Example 27 or Examples 5A, 27A and 26A together with 5-(chloromethyl)-1H-tetrazole [55408-11-2].

[0779] Embodiment 115: 2-(2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)-N-(methylsulfonyl)acetamide, Compound 115

[0780] Compound 115 can be prepared from compound 111 and methanesulfonamide.

[0781] Embodiment 116:2-(2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)-N-hydroxyacetamide, Compound 116

[0782] Compound 116 can be prepared from compound 111 and hydroxylamine.

[0783] Embodiment 117: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-((3-hydroxyisoxazol-5-yl)methyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 117

[0784] Compound 117 can be prepared according to the method of Example 27 or Examples 5A and 27A and 26A together with (3-((4-methoxybenzyl)oxy)isoxazol-5-yl)methanol mesylate.

[0785] Embodiment 118: 5-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)thiophene-2-carboxylic acid methyl ester, Compound 118

[0786] Compound 118 can be prepared according to the method in Example 27 or Examples 5A, 27A and 26A together with methyl 5-(bromomethyl)thiophene-2-carboxylate [108499-32-7].

[0787] Embodiment 119: 5-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)thiophene-2-carboxylic acid, Compound 119

[0788] Compound 119 can be prepared by ester hydrolysis of compound 118.

[0789] Embodiment 120: 5-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)thiophene-3-carboxylic acid ethyl ester, Compound 120

[0790] Compound 120 can be prepared according to the method in Example 27 or Examples 5A, 27A and 26A together with ethyl 5-(bromomethyl)thiophene-3-carboxylate [206860-16-4].

[0791] Embodiment 121: 5-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)thiophene-3-carboxylic acid, Compound 121

[0792] Compound 121 can be prepared by ester hydrolysis of compound 120.

[0793] Embodiment 122: 4-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)thiophene-2-carboxylic acid methyl ester, Compound 122

[0794] Compound 122 can be prepared according to the method in Example 27 or Examples 5A, 27A and 26A together with methyl 4-(bromomethyl)thiophene-2-carboxylate [54796-51-9].

[0795] Embodiment 123: 4-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)thiophene-2-carboxylic acid, Compound 123

[0796] Compound 123 can be prepared by ester hydrolysis of compound 122.

[0797] Embodiment 124: (1R,2R)-2-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)cyclopropane-1-carboxylic acid, Compound 124

[0798] Compound 124 can be prepared according to the method of Example 27 or Examples 5A, 27A and 26A using the mesylate of ethyl (1R,2R)-2-(hydroxymethyl)cyclopropane-1-carboxylate followed by ester hydrolysis.

[0799] Embodiment 125:7-((E)-3-(1H-tetrazolyl-5-yl)allyl)-2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 125

[0800] Compound 125 can be prepared from 7-allyl-2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione and 5-vinyl-1H-tetrazole [18755-47-0].

[0801] Embodiment 126: 4-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzaldehyde, Compound 126 Compound 126 can be prepared according to the method in Example 27 or Examples 5A and 27A and 26A together with methyl 4-(bromomethyl)benzaldehyde.

[0802] Embodiment 127: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4-methoxybenzyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 127

[0803] Compound 127 can be prepared according to the method in Example 26 or Examples 5A and 27A and 26A together with 4-methoxy-benzyl bromide.

[0804] Embodiment 128: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(3-methoxybenzyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 128

[0805] Compound 128 can be prepared according to the method in Example 26 or Examples 5A and 27A and 26A together with 3-methoxy-benzyl bromide.

[0806] Embodiment 129: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(3-hydroxybenzyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 129

[0807] Compound 129 can be prepared by using BBr 3Prepared by demethylating compound 128.

[0808] Embodiment 130: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4-(trifluoromethyl)benzyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 130

[0809] Compound 130 was prepared from 2-amino-7-(4-(trifluoromethyl)benzyl)-7,9-dihydro-1H-purine-6,8-dione and (2S,3S,4R,5R)-5-((benzoyloxy)methyl)-4-fluorotetrahydrofuran-2,3-diacetic acid diester using the same general method described in Example 35 (Compound 35).

[0810] Embodiment 131: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(pyridin-3-ylmethyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 131

[0811] Compound 131 can be prepared according to the method in Example 27 or Examples 5A, 27A and 26A together with 3-bromomethylpyridine.

[0812] Embodiment 132: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(2-oxo-2-(pyrrolidin-1-yl)ethyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 132

[0813] Compound 132 can be prepared according to the method in Example 27 or Examples 5A, 27A and 26A together with bromoacetylpyrrolidine [90892-09-4].

[0814] Embodiment 133: 7-allyl-2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 133

[0815] Compound 133 was prepared from N-(7-allyl-6,8-dioxo-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide and (2S,3S,4R,5R)-5-((benzoyloxy)methyl)-4-fluorotetrahydrofuran-2,3-diacetic acid diester using the same general method as described in Example 36 (Compound 36).

[0816] Embodiment 134: 2-amino-7-(cyclopropylmethyl)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 134

[0817] Compound 134 can be prepared by the method of Example 1 using 3'-deoxy-(3'S)-fluoro-guanosine [123402-21-1] instead of 2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1,9-dihydro-6H-purin-6-one (1) [27462-39-1] or by the method of Example 27A using (74) instead of (40).

[0818] Embodiment 135: 2-Amino-7-butyl-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 135

[0819] Compound 135 can be prepared from N-(7-butyl-6,8-dioxo-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (68) and / or N-acetyl-N-(7-butyl-6,8-dioxo-6,7,8,9-tetrahydro-1H-purin-2-yl)acetamide (68a) and (2S,3S,4R,5R)-5-((benzoyloxy)methyl)-4-fluorotetrahydrofuran-2,3-diacetic acid diester using the same general method described in Example 37 (Compound 37).

[0820] Embodiment 136: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(methoxymethyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 136

[0821] Compound 136 can be prepared according to the method of Example 27 using chloromethyl methyl ether.

[0822] Embodiment 137: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-((methylthio)methyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 137

[0823] Compound 137 can be prepared according to the method of Example 27 using chloromethyl methyl sulfide.

[0824] Embodiment 138:2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(2,2,2-trifluoroethyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 138

[0825] Compound 138 can be prepared according to the method in Example 27 or Examples 5A, 27A and 26A together with 2-bromo-1,1,1-trifluoroethane [421-06-7].

[0826] Embodiment 139: 2-Amino-7-(2,2-difluoroethyl)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione, Compound 139

[0827] Compound 139 can be prepared according to the method in Example 27 or Examples 5A, 27A and 26A together with 2-bromo-1,1-difluoroethane [359-07-9].

[0828] Embodiment 140: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(3,3,3-trifluoropropyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 140

[0829] Compound 140 can be prepared according to the method of Example 26 or Examples 5A, 27A and 26A together with 3-bromo-1,1,1-trifluoropropane [460-32-2].

[0830] Example 141: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(2,2,3,3,3-pentafluoropropyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 141

[0831] Compound 141 can be prepared according to the method of Example 27 or Examples 5A, 27A and 26A together with 3-bromo-1,1,1,2,2-pentafluoropropane [422-01-5] or 2,2,3,3,3-pentafluoropropyl methanesulfonate [813-31-0].

[0832] Embodiment 142: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4,4,4-trifluorobutyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 142

[0833] Compound 142 can be prepared according to the method in Example 27 or Examples 5A, 27A and 26A together with 4-bromo-1,1,1-trifluorobutane [406-81-5].

[0834] Embodiment 143: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(3,3,4,4,4-pentafluorobutyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 143

[0835] Compound 143 can be prepared according to the method of Example 27 or Examples 5A, 27A and 26A together with 1,1,1,2,2-pentafluoro-4-bromobutane [52671-70-2].

[0836] Embodiment 144: 3-(2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)propionitrile, Compound 144

[0837] Compound 144 can be prepared according to the method in Example 27 or Examples 5A, 27A and 26A together with 3-bromopropionitrile [2417-90-5].

[0838] Embodiment 145: 4-(2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)butanenitrile, Compound 145

[0839] Compound 145 can be prepared according to the method in Example 27 or Examples 5A, 27A and 26A together with 3-bromobutyronitrile [5332-06-9].

[0840] Embodiment 146: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-isobutyl-7,9-dihydro-1H-purine-6,8-dione, Compound 146

[0841] Compound 146 can be prepared according to the method of Example 27 or Examples 5A, 27A and 26A together with 1-bromo-2-methylpropane.

[0842] Embodiment 147:1-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)cyclopropane-1-carbonitrile, Compound 147

[0843] Compound 147 can be prepared according to the method of Example 27 or Examples 5A, 27A and 26A together with the mesylate of 1-(hydroxymethyl)cyclopropane-1-carbonitrile [98730-77-9].

[0844] Embodiment 148: 1-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)cyclopropane-1-carboxylic acid, Compound 148

[0845] Compound 148 can be prepared according to the method in Example 27 or Examples 5A, 27A and 26A together with the mesylate of ethyl 1-(hydroxymethyl)cyclopropane-1-carboxylate [3697-68-5].

[0846] Embodiment 149: 2-Amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-((1-(trifluoromethyl)cyclopropyl)methyl)-7,9-dihydro-1H-purine-6,8-dione, Compound 149

[0847] Compound 149 can be prepared according to the method in Example 27 or Examples 5A, 27A and 26A together with (1-(trifluoromethyl)cyclopropyl)methanol [371917-17-8].

[0848] Embodiment 150: ((2S,4R,5R)-4-Acetoxy-5-(2-amino-7-benzyl-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 150

[0849] Compound 150 can be prepared according to the procedure outlined in Example 29, substituting benzyl bromide for propargyl bromide.

[0850] Embodiment 151: 2-amino-7-benzyl-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, Compound 151

[0851] Compound 151 can be prepared by ester hydrolysis of compound 150 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting benzyl bromide for propargyl bromide.

[0852] Embodiment 152: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(4-fluorobenzyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 152

[0853] Compound 152 can be prepared according to the procedure outlined in Example 29, substituting 4-fluorobenzyl bromide for propargyl bromide.

[0854] Embodiment 153: 2-amino-7-(4-fluorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, Compound 153

[0855] Compound 153 can be prepared by ester hydrolysis of compound 150 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 4-fluorobenzyl bromide for propargyl bromide.

[0856] Embodiment 154: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(3-fluorobenzyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 154

[0857] Compound 154 can be prepared according to the procedure outlined in Example 29, substituting 3-fluorobenzyl bromide for propargyl bromide.

[0858] Embodiment 155: 2-amino-7-(3-fluorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, Compound 155

[0859] Compound 155 can be prepared by ester hydrolysis of compound 154 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 3-fluorobenzyl bromide for propargyl bromide.

[0860] Embodiment 156: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(3,4-difluorobenzyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 156

[0861] Compound 156 can be prepared according to the procedure outlined in Example 29, substituting 3,4-difluorobenzyl bromide for propargyl bromide.

[0862] Embodiment 157: 2-amino-7-(3,4-difluorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, Compound 157

[0863] Compound 157 can be prepared by ester hydrolysis of compound 156 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 3,4-difluorobenzyl bromide for propargyl bromide.

[0864] Embodiment 158: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(4-chlorobenzyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 158

[0865] Compound 158 can be prepared according to the procedure outlined in Example 29, substituting 4-chlorobenzyl bromide for propargyl bromide.

[0866] Embodiment 159: 2-amino-7-(4-chlorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, Compound 159

[0867] Compound 159 can be prepared by ester hydrolysis of compound 158 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 4-chlorobenzyl bromide for propargyl bromide.

[0868] Embodiment 160: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(3-chlorobenzyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 160

[0869] Compound 160 can be prepared according to the procedure outlined in Example 29, substituting 3-chlorobenzyl bromide for propargyl bromide.

[0870] Example 161: 2-amino-7-(3-chlorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, Compound 161

[0871] Compound 161 can be prepared by ester hydrolysis of compound 160 according to the method outlined in Example 30 or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 3-chlorobenzyl bromide for propargyl bromide.

[0872] Embodiment 162: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(3,4-dichlorobenzyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 162

[0873] Compound 162 can be prepared according to the procedure outlined in Example 29, substituting 3,4-dichlorobenzyl bromide for propargyl bromide.

[0874] Embodiment 163: 2-amino-7-(3,4-dichlorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, Compound 163

[0875] Compound 163 can be prepared by ester hydrolysis of compound 162 according to the method outlined in Example 30 or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 3,4-dichlorobenzyl bromide for propargyl bromide.

[0876] Embodiment 164: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(4-cyanobenzyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 164

[0877] Compound 164 can be prepared according to the procedure outlined in Example 29, substituting 4-cyanobenzyl bromide for propargyl bromide.

[0878] Embodiment 165: 4-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)benzonitrile, Compound 165

[0879] Compound 165 can be prepared by ester hydrolysis of compound 164 according to the method outlined in Example 30 or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 4-cyanobenzyl bromide for propargyl bromide.

[0880] Example 166: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(3-cyanobenzyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 166

[0881] Compound 166 can be prepared according to the procedure outlined in Example 29, substituting 3-cyanobenzyl bromide for propargyl bromide.

[0882] Example 167: 3-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)benzonitrile, Compound 167

[0883] Compound 167 can be prepared by ester hydrolysis of compound 166 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 3-cyanobenzyl bromide for propargyl bromide.

[0884] Embodiment 168: Methyl 4-((9-((2R,3R,5S)-3-acetoxy-5-(acetoxymethyl)tetrahydrofuran-2-yl)-2-amino-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)benzoate, Compound 168 Compound 168 can be prepared according to the method outlined in Example 29, substituting methyl 4-bromomethylbenzoate for propargyl bromide.

[0885] Example 168a: Methyl 4-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)benzoate, Compound 168a

[0886] Compound 168a can be prepared by exposing compound 168 to potassium carbonate in anhydrous methanol.

[0887] Embodiment 169: 4-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)benzoic acid, Compound 169

[0888] Compound 169 can be prepared by ester hydrolysis of compound 168 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting methyl 4-bromomethylbenzoate for propargyl bromide.

[0889] Embodiment 170: Methyl 3-((9-((2R,3R,5S)-3-acetoxy-5-(acetoxymethyl)tetrahydrofuran-2-yl)-2-amino-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)benzoate, Compound 170

[0890] Compound 170 can be prepared according to the procedure outlined in Example 29, substituting methyl 3-bromomethylbenzoate for propargyl bromide.

[0891] Example 170a: Methyl 3-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)benzoate, Compound 170a

[0892] Compound 170a can be prepared by exposing compound 170 to potassium carbonate in anhydrous methanol.

[0893] Embodiment 171: 3-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)benzoic acid, Compound 171

[0894] Compound 171 can be prepared by ester hydrolysis of compound 170 according to the method outlined in Example 30 or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting methyl 3-bromomethylbenzoate for propargyl bromide.

[0895] Embodiment 172: Methyl 2-((9-((2R,3R,5S)-3-acetoxy-5-(acetoxymethyl)tetrahydrofuran-2-yl)-2-amino-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)benzoate, Compound 172

[0896] Compound 172 can be prepared according to the procedure outlined in Example 29, substituting methyl 2-bromomethylbenzoate for propargyl bromide.

[0897] Example 172a: Methyl 2-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)benzoate, Compound 172a

[0898] Compound 172a can be prepared by exposing compound 172 to potassium carbonate in anhydrous methanol.

[0899] Embodiment 173: 2-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)benzoic acid, Compound 173

[0900] Compound 173 can be prepared by ester hydrolysis of compound 172 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting methyl 2-bromomethylbenzoate for propargyl bromide.

[0901] Embodiment 174: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(E)-cinnamyl-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 174

[0902] Compound 174 can be prepared according to the procedure outlined in Example 29, substituting (E)-cinnamyl bromide for propargyl bromide.

[0903] Embodiment 175: 2-Amino-7-(E)-cinnamyl-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, Compound 175

[0904] Compound 175 can be prepared by ester hydrolysis of compound 174 according to the method outlined in Example 30 or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting (E)-cinnamyl bromide for propargyl bromide.

[0905] Embodiment 176: ((2S,4R,5R)-5-(7-((1H-pyrazol-5-yl)methyl)-2-amino-8-oxo-7,8-dihydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl acetate, Compound 176

[0906] Compound 176 can be prepared according to the method of Example 29, using tert-butyl 5-(bromomethyl)-1H-pyrazole-1-carboxylate [1001096-27-0] or 5-(bromomethyl)-1-(4-methoxybenzyl)-1H-pyrazole [1313409-97-0] or (1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazol-5-yl)methanol [1823866-20-1] methanesulfonate instead of propargyl bromide.

[0907] Embodiment 177:7-((1H-pyrazol-5-yl)methyl)-2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, Compound 177

[0908] Compound 177 can be prepared by ester hydrolysis of compound 176 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting propargyl bromide for tert-butyl 5-(bromomethyl)-1H-pyrazole-1-carboxylate or the mesylate of 5-(bromomethyl)-1-(4-methoxybenzyl)-1H-pyrazole or (1-(tetrahydro-2H-pyran-2-yl)-1H-pyrazol-5-yl)methanol.

[0909] Embodiment 178: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-((1-methyl-1H-pyrazol-3-yl)methyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 178

[0910] Compound 178 can be prepared according to the procedure outlined in Example 29, substituting 3-(bromomethyl)-1-methyl-1H-pyrazole [102846-13-9] for propargyl bromide.

[0911] Embodiment 179: 2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-((1-methyl-1H-pyrazol-3-yl)methyl)-7,9-dihydro-8H-purin-8-one, Compound 179

[0912] Compound 179 can be prepared by ester hydrolysis of compound 178 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 3-(bromomethyl)-1-methyl-1H-pyrazole for propargyl bromide.

[0913] Embodiment 180: ((2S,4R,5R)-4-Acetoxy-5-(2-amino-8-oxo-7-(thien-2-ylmethyl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 180

[0914] Compound 180 can be prepared according to the procedure outlined in Example 29, substituting 2-(bromomethyl)-thiophene for propargyl bromide.

[0915] Embodiment 181: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(thiophen-2-ylmethyl)-7,9-dihydro-8H-purin-8-one, Compound 181

[0916] Compound 181 can be prepared by ester hydrolysis of compound 180 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 2-(bromomethyl)-thiophene for propargyl bromide.

[0917] Embodiment 182: ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(thien-2-ylmethyl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3-yl)methyl acetate, Compound 182

[0918] Compound 182 can be prepared according to the procedure outlined in Example 29, substituting 3-(bromomethyl)-thiophene for propargyl bromide.

[0919] Embodiment 183: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(thiophen-3-ylmethyl)-7,9-dihydro-8H-purin-8-one, Compound 183

[0920] Compound 183 can be prepared by ester hydrolysis of compound 182 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (3S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 2-(bromomethyl)-thiophene for propargyl bromide.

[0921] Embodiment 184: 2-(9-((2R,3R,5S)-3-acetoxy-5-(acetoxymethyl)tetrahydrofuran-2-yl)-2-amino-8-oxo-8,9-dihydro-7H-purin-7-yl)acetate, Compound 184

[0922] Compound 184 can be prepared according to the procedure outlined in Example 29, substituting methyl 2-bromoacetate for propargyl bromide.

[0923] Example 184a: 2-(2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)acetic acid methyl ester Compound 184a

[0924] Compound 184a can be prepared by exposing compound 184 to potassium carbonate in anhydrous methanol.

[0925] Embodiment 185: 2-(2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)acetic acid, Compound 185

[0926] Compound 185 can be prepared by ester hydrolysis of compound 184 under aqueous conditions using a modified method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting methyl 2-bromoacetate for propargyl bromide and subsequent ester hydrolysis.

[0927] Embodiment 186: ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(2-oxoethyl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 186

[0928] Compound 186 can be prepared according to the general procedure outlined in Example 29, substituting 2-bromo-1,1-dimethoxyethane for propargyl bromide, followed by aqueous acid workup.

[0929] Embodiment 187: 2-(2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)acetaldehyde, Compound 187

[0930] Compound 187 can be prepared by base hydrolysis of compound 186 or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 2-bromo-1,1-dimethoxyethane for propargyl bromide followed by acetal and ester hydrolysis.

[0931] Embodiment 188: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(cyanomethyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 188

[0932] Compound 188 can be prepared according to the general procedure outlined in Example 29, substituting 2-bromoacetonitrile for propargyl bromide.

[0933] Embodiment 189: 2-(2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)acetonitrile, Compound 189

[0934] Compound 189 can be prepared by hydrolysis of compound 188 or from the hydrolysis of compound 187 by converting the aldehyde to the corresponding oxime followed by dehydration.

[0935] Embodiment 190: ((2S,4R,5R)-5-(7-((1H-tetrazol-5-yl)methyl)-2-amino-8-oxo-7,8-dihydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl acetate, Compound 190

[0936] Compound 190 can be prepared according to the procedure outlined in Example 29, substituting 5-(chloromethyl)-1H-tetrazole [55408-11-2] for propargyl bromide.

[0937] Example 191: 7-((1H-tetrazolyl-5-yl)methyl)-2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, Compound 191

[0938] Compound 191 can be prepared by ester hydrolysis of compound 190 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 5-(chloromethyl)-1H-tetrazole for propargyl bromide.

[0939] Embodiment 192: 2-(2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)-N-(methylsulfonyl)acetamide, Compound 192

[0940] Compound 192 can be prepared from compound 185 and methanesulfonamide.

[0941] Embodiment 193: 2-(2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)-N-hydroxyacetamide, Compound 193

[0942] Compound 193 can be prepared from compound 185 and hydroxylamine.

[0943] Embodiment 194: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-((3-hydroxyisoxazol-5-yl)methyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 194

[0944] Compound 194 can be prepared according to the method outlined in Example 29 together with the mesylate of (3-((4-methoxybenzyl)oxy)isoxazol-5-yl)methanol.

[0945] Embodiment 195: 2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-((3-hydroxyisoxazol-5-yl)methyl)-7,9-dihydro-8H-purin-8-one, Compound 195

[0946] Compound 195 can be prepared by ester hydrolysis of compound 194 according to the method outlined in Example 30.

[0947] Embodiment 196:5-((9-((2R,3R,5S)-3-acetoxy-5-(acetoxymethyl)tetrahydrofuran-2-yl)-2-amino-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)thiophene-2-carboxylic acid methyl ester, Compound 196

[0948] Compound 196 can be prepared according to the procedure outlined in Example 29 using methyl 5-(bromomethyl)thiophene-2-carboxylate [108499-32-7].

[0949] Example 196a: 5-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)thiophene-2-carboxylic acid methyl ester, Compound 196a

[0950] Compound 196a can be prepared by exposing compound 196 to potassium carbonate in anhydrous methanol.

[0951] Embodiment 197: 5-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)thiophene-2-carboxylic acid, Compound 197

[0952] Compound 197 can be prepared by ester hydrolysis of compound 196 according to the method outlined in Example 30.

[0953] Embodiment 198: 5-((9-((2R,3R,5S)-3-acetoxy-5-(acetoxymethyl)tetrahydrofuran-2-yl)-2-amino-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)thiophene-3-carboxylic acid ethyl ester, Compound 198

[0954] Compound 198 can be prepared according to the procedure outlined in Example 29 using ethyl 5-(bromomethyl)thiophene-3-carboxylate [206860-16-4].

[0955] Example 198a: 5-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)thiophene-3-carboxylic acid ethyl ester, Compound 198a

[0956] Compound 198a can be prepared by exposing compound 198 to potassium carbonate in dry ethanol.

[0957] Embodiment 199:5-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)thiophene-3-carboxylic acid, Compound 199

[0958] Compound 199 can be prepared by ester hydrolysis of compound 198 according to the method outlined in Example 30.

[0959] Embodiment 200: 4-((9-((2R,3R,5S)-3-acetoxy-5-(acetoxymethyl)tetrahydrofuran-2-yl)-2-amino-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)thiophene-2-carboxylic acid methyl ester, Compound 200 Compound 200 can be prepared according to the method outlined in Example 29 using 4-(bromomethyl)thiophene-2-carboxylic acid methyl ester [54796-51-9].

[0960] Embodiment 200a: 4-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)thiophene-2-carboxylic acid methyl ester, Compound 200a

[0961] Compound 200a can be prepared by exposing compound 200 to potassium carbonate in anhydrous methanol.

[0962] Embodiment 201: 4-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)thiophene-2-carboxylic acid, Compound 201

[0963] Compound 201 can be prepared by ester hydrolysis of compound 200 according to the method outlined in Example 30.

[0964] Embodiment 202: (1R,2R)-2-((9-((2R,3R,5S)-3-acetoxy-5-(acetoxymethyl)tetrahydrofuran-2-yl)-2-amino-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)cyclopropane-1-carboxylic acid ethyl ester, Compound 202

[0965] Compound 202 was prepared according to the method outlined in Example 29 together with the mesylate of ethyl (1R,2R)-2-(hydroxymethyl)cyclopropane-1-carboxylate.

[0966] Embodiment 202a:(1R,2R)-2-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)cyclopropane-1-carboxylic acid ethyl ester, Compound 202a

[0967] Compound 202a can be prepared by exposing compound 202 to potassium carbonate in dry ethanol.

[0968] Embodiment 203: (1R,2R)-2-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)cyclopropane-1-carboxylic acid, Compound 203

[0969] Compound 203 can be prepared by ester hydrolysis of compound 202 according to the method outlined in Example 30.

[0970] Embodiment 204: ((2S,4R,5R)-5-(7-((E)-3-(1H-tetrazol-5-yl)allyl)-2-amino-8-oxo-7,8-dihydro-9H-purin-9-yl)-4-acetoxytetrahydrofuran-2-yl)methyl acetate, Compound 204

[0971] Compound 204 can be prepared from ((2S,4R,5R)-4-acetoxy-5-(7-allyl-2-amino-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate and 5-vinyl-1H-tetrazole [18755-47-0] via an olefin metathesis-type reaction.

[0972] Embodiment 205: 7-((E)-3-(1H-tetrazolyl-5-yl)allyl)-2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, Compound 205

[0973] Compound 205 can be prepared by ester hydrolysis of compound 204 according to the method outlined in Example 30.

[0974] Embodiment 206: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(4-formylbenzyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 206

[0975] Compound 206 can be prepared according to the procedure outlined in Example 29, substituting 4-(bromomethyl)benzaldehyde for propargyl bromide.

[0976] Embodiment 207: 4-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-8-oxo-8,9-dihydro-7H-purin-7-yl)methyl)benzaldehyde, Compound 207

[0977] Compound 207 can be prepared by ester hydrolysis of compound 206 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (4S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 4-(bromomethyl)benzaldehyde for propargyl bromide.

[0978] Embodiment 208: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(4-methoxybenzyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 208

[0979] Compound 208 can be prepared according to the procedure outlined in Example 29, substituting 4-methoxy-benzyl bromide for propargyl bromide.

[0980] Embodiment 209: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4-methoxybenzyl)-7,9-dihydro-8H-purin-8-one, Compound 209

[0981] Compound 209 can be prepared by ester hydrolysis of compound 208 according to the method outlined in Example 30.

[0982] Embodiment 210: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(3-methoxybenzyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 210

[0983] Compound 210 can be prepared according to the procedure outlined in Example 29, substituting 3-methoxy-benzyl bromide for propargyl bromide.

[0984] Example 211:2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(3-methoxybenzyl)-7,9-dihydro-8H-purin-8-one, Compound 211

[0985] Compound 211 can be prepared by ester hydrolysis of compound 210 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 3-methoxy-benzyl bromide for propargyl bromide.

[0986] Embodiment 212: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(3-hydroxybenzyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 212

[0987] Compound 212 can be prepared by using BBr 3 Prepared by demethylating compound 211.

[0988] Embodiment 213: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(3-hydroxybenzyl)-7,9-dihydro-8H-purin-8-one, Compound 213

[0989] Compound 213 can be prepared by ester hydrolysis of compound 212 according to the method outlined in Example 30.

[0990] Embodiment 214: ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(4-(trifluoromethyl)benzyl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 214

[0991] Compound 214 can be prepared according to the procedure outlined in Example 29, substituting 4-trifluoromethyl-benzyl bromide for propargyl bromide.

[0992] Embodiment 215: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4-(trifluoromethyl)benzyl)-7,9-dihydro-8H-purin-8-one, Compound 215

[0993] Compound 215 can be prepared by ester hydrolysis of compound 214 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 4-trifluoromethyl-benzyl bromide for propargyl bromide.

[0994] Example 216: ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(pyridin-3-ylmethyl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 216

[0995] Compound 216 can be prepared according to the procedure outlined in Example 29, substituting 3-(bromomethyl)pyridine for propargyl bromide.

[0996] Example 217: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(pyridin-3-ylmethyl)-7,9-dihydro-8H-purin-8-one, Compound 217

[0997] Compound 217 can be prepared by ester hydrolysis of compound 216 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (3S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 3-(bromomethyl)pyridine for propargyl bromide.

[0998] Embodiment 218: ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(2-oxo-2-(pyrrolidin-1-yl)ethyl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 218

[0999] Compound 218 can be prepared according to the procedure outlined in Example 29, substituting bromoacetylpyrrolidine [90892-09-4] for propargyl bromide.

[1000] Embodiment 219: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(2-oxo-2-(pyrrolidin-1-yl)ethyl)-7,9-dihydro-8H-purin-8-one, Compound 219

[1001] Compound 219 can be prepared by ester hydrolysis of compound 218 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting pyrrolidine bromoacetate for propargyl bromide.

[1002] Example 220: ((2S,4R,5R)-4-Acetoxy-5-(7-allyl-2-amino-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 220

[1003] Compound 220 can be prepared according to the procedure outlined in Example 29, substituting allyl bromide for propargyl bromide.

[1004] Example 221: 7-allyl-2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, Compound 221

[1005] Compound 221 can be prepared by ester hydrolysis of compound 220 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting allyl bromide for propargyl bromide.

[1006] Example 222: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(cyclopropylmethyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 222

[1007] Compound 222 can be prepared according to the procedure outlined in Example 29, substituting (bromomethyl)cyclopropane for propargyl bromide.

[1008] Example 223: 2-amino-7-(cyclopropylmethyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one Compound 223

[1009] Compound 223 can be prepared by ester hydrolysis of compound 222 according to the method outlined in Example 30 or from (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A and substituting (71) for (45).

[1010] Example 224: ((2S,4R,5R)-4-Acetoxy-5-(2-amino-7-butyl-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 224

[1011] Compound 224 can be prepared according to the procedure outlined in Example 29, substituting n-butyl bromide for propargyl bromide.

[1012] Example 225: 2-Amino-7-butyl-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, Compound 225

[1013] Compound 225 can be prepared by ester hydrolysis of compound 224 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting n-butyl bromide for propargyl bromide.

[1014] Example 226: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(methoxymethyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 226

[1015] Compound 226 can be prepared according to the procedure outlined in Example 29, using chloromethyl methyl ether in place of propargyl bromide.

[1016] Example 227: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(methoxymethyl)-7,9-dihydro-8H-purin-8-one, Compound 227

[1017] Compound 227 can be prepared by ester hydrolysis of compound 226 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting chloromethyl methyl ether for propargyl bromide.

[1018] Example 228: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-((methylthio)methyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 228

[1019] Compound 228 can be prepared according to the procedure outlined in Example 29, using chloromethyl methyl sulfide in place of propargyl bromide.

[1020] Example 229: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-((methylthio)methyl)-7,9-dihydro-8H-purin-8-one, Compound 229

[1021] Compound 229 can be prepared by ester hydrolysis of compound 228 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting chloromethyl methyl sulfide for propargyl bromide.

[1022] Embodiment 230: ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(2,2,2-trifluoroethyl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 230

[1023] Compound 230 can be prepared according to the general procedure outlined in Example 29, substituting 2-bromo-1,1,1-trifluoroethane [421-06-7] for propargyl bromide.

[1024] Example 231: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(2,2,2-trifluoroethyl)-7,9-dihydro-8H-purin-8-one, Compound 231

[1025] Compound 231 can be prepared by ester hydrolysis of compound 230 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 2-bromo-1,1,1-trifluoroethane for propargyl bromide.

[1026] Example 232: ((2S,4R,5R)-4-acetoxy-5-(2-amino-7-(2,2-difluoroethyl)-8-oxo-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 232

[1027] Compound 232 can be prepared according to the general procedure outlined in Example 29, substituting 2-bromo-1,1-difluoroethane [359-07-9] for propargyl bromide.

[1028] Embodiment 233: 2-amino-7-(2,2-difluoroethyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one, Compound 233

[1029] Compound 233 can be prepared by ester hydrolysis of compound 232 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (2S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 2-bromo-1,1-difluoroethane for propargyl bromide.

[1030] Embodiment 234: ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(3,3,3-trifluoropropyl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 234

[1031] Compound 234 can be prepared according to the general procedure outlined in Example 29, substituting 3-bromo-1,1,1-trifluoropropane [460-32-2] for propargyl bromide.

[1032] Example 235: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(3,3,3-trifluoropropyl)-7,9-dihydro-8H-purin-8-one, Compound 235

[1033] Compound 235 can be prepared by ester hydrolysis of compound 234 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (3S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 3-bromo-1,1,1-trifluoropropane for propargyl bromide.

[1034] Example 236: ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(2,2,3,3,3-pentafluoropropyl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 236

[1035] Compound 236 can be prepared according to the general procedure outlined in Example 29, substituting 3-bromo-1,1,1,2,2-pentafluoropropane [422-01-5] or 2,2,3,3,3-pentafluoropropyl methanesulfonate [813-31-0] for propargyl bromide.

[1036] Example 237: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(2,2,3,3,3-pentafluoropropyl)-7,9-dihydro-8H-purin-8-one, Compound 237

[1037] Compound 237 can be prepared by ester hydrolysis of compound 236 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (3S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 3-bromo-1,1,1,2,2-pentafluoropropane or 2,2,3,3,3-pentafluoropropyl methanesulfonate for propargyl bromide.

[1038] Embodiment 238: ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(4,4,4-trifluorobutyl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate, Compound 238

[1039] Compound 238 can be prepared according to the general procedure outlined in Example 29, substituting 4-bromo-1,1,1-trifluorobutane [406-81-5] for propargyl bromide.

[1040] Embodiment 239:2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4,4,4-trifluorobutyl)-7,9-dihydro-8H-purin-8-one, Compound 239

[1041] Compound 239 can be prepared by ester hydrolysis of compound 238 according to the method outlined in Example 30, or from N-(9-(4-methoxybenzyl)-8-oxo-8,9-dihydro-7H-purin-2-yl)acetamide and (4S,3R,5S)-5-((benzoyloxy)methyl)tetrahydrofuran-2,3-diacetic acid diester using the method described in Example 32A, substituting 4-bromo-1,1,1-trifluorobutane for propargyl bromide.

[1042] Embodiment 240: ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(3,3,4,4,4-pentafluorobutyl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate Compound 240

[1043] Compound 240 can be prepared according to the procedure outlined in Example 29, substituting 1,1,1,2,2-pentafluoro-4-bromobutane [52671-70-2] for propargyl bromide.

[1044] Example 241: 2-Amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(3,3,4,4,4-pentafluorobutyl)-7,9-dihydro-8H-purin-8-one, Compound 241

[1045] Compound 241 can be prepared by ester hydrolysis of compound 240 according to the method outlined in...

Claims

1. A compound having a structure of Formula I: in R 1 is –H or –F, R 2 is –H or –F, R 3 Yes –OH, R 4 is –(C1-C8)alkyl, –(C2-C8)alkenyl, –(C2-C8)alkynyl, –(C1-C8)haloalkyl, –(CH2) n (C3-C 10 Cycloalkyl), –(CH2) n (C6-C 18 Aryl), –(CH2) n (5-14 membered heteroaryl) or –(CH2) n C(O)OR 6 , R 5 Yes –OH, R 6 is –(C1-C8)alkyl, n is an integer of 1, 2, 3 or 4, wherein each alkyl, cycloalkyl, alkenyl, alkynyl, haloalkyl, aryl and heteroaryl is independently substituted by CN, halogen, (C1-C3)haloalkyl, (C6-C 18 )aryl, OH, O-(C1-C3)alkyl, C(O)OR 8 、C(O)NR 8 R 8 NR 8 R 8 Optionally replace, And R 8 is -H, or C(O)NR 8 R 8 The two R's 8 Combined with nitrogen atoms to form a 3-9 membered heterocyclic ring; or a pharmaceutically acceptable salt thereof.

2. The compound of claim 1, wherein R 1 and R 2 is -H, or a pharmaceutically acceptable salt thereof.

3. The compound as claimed in claim 1, wherein R 1 Is -H and R 2 is -F, or a pharmaceutically acceptable salt thereof.

4. The compound as claimed in claim 1, wherein R 4 It is -(CH2)(cyclopropyl), -CH2C≡CH, -(CH2)3CH3, or -CH2CF3, or a pharmaceutically acceptable salt thereof.

5. A compound selected from: 2-amino-7-(cyclopropylmethyl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 1); 7-allyl-2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 2); 2-amino-7-(cyclopropylmethyl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-8H-purin-8-one (Compound 4); 2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 5); 2-amino-7-(but-2-yn-1-yl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 6); 2-amino-7-((E)-but-2-en-1-yl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 7); 2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-((E)-4-hydroxybut-2-en-1-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 8); (E)-4-(2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)but-2-enoic acid (Compound 9); (E)-4-(2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)but-2-enoic acid methyl ester (Compound 10); 2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4-hydroxybut-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 11); 2-(2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)acetate (Compound 12); 2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(2,2,2-trifluoroethyl)-7,9-dihydro-1H-purine-6,8-dione (Compound 13); 2-amino-7-(2,2-difluoroethyl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 14); 2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-methyl-7,9-dihydro-1H-purine-6,8-dione (Compound 15); 2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-ethyl-7,9-dihydro-1H-purine-6,8-dione (Compound 16); 2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-propyl-7,9-dihydro-1H-purine-6,8-dione (Compound 17); 2-amino-7-butyl-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 18); 2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4-hydroxybutyl)-7,9-dihydro-1H-purine-6,8-dione (Compound 19); 4-(2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)butanoic acid (Compound 20); 4-(2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)butanoic acid methyl ester (Compound 21); 2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(2-methoxyethyl)-7,9-dihydro-1H-purine-6,8-dione (Compound 22); 2-amino-7-(2-aminoethyl)-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione hydrochloride (Compound 23); (2R,3S,4R,5R)-2-(acetoxymethyl)-5-(2-amino-8-oxo-7-(prop-2-yn-yl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-3,4-diyl diacetate (Compound 24); 2-amino-9-((2R,3R,4R,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one (Compound 25); 2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 26); 2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 27); 2-amino-9-((2R,3S,4R,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 28); ((2S,4R,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purin-9-yl)tetrahydrofuran-2-yl)methyl acetate (Compound 29); 2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one (Compound 30); ((2R,3R,4S,5R)-4-acetoxy-5-(2-amino-8-oxo-7-(prop-2-yn-1-yl)-7,8-dihydro-9H-purin-9-yl)-3-fluorotetrahydrofuran-2-yl)methyl acetate (Compound 31); 2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one (Compound 32); 2-amino-7-benzyl-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 33); 2-amino-7-(3-fluorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 34); 2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4-(trifluoromethyl)benzyl)-7,9-dihydro-1H-purine-6,8-dione (Compound 35); 7-allyl-2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 36); 2-amino-7-butyl-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 37); 2-amino-7-(4-fluorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 38); 2-amino-7-(3,4-difluorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 39); 2-amino-7-(4-chlorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 40); 2-amino-7-(3-chlorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 41); 2-amino-7-(3,4-dichlorobenzyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 42); 3-((2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzonitrile (Compound 44); 2-amino-7-(cyclopropylmethyl)-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 77); 2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-isobutyl-7,9-dihydro-1H-purine-6,8-dione (Compound 88); 2-amino-7-benzyl-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 92); 2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4-fluorobenzyl)-7,9-dihydro-1H-purine-6,8-dione (Compound 93); 2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(3-fluorobenzyl)-7,9-dihydro-1H-purine-6,8-dione (Compound 94); 2-amino-7-(3,4-difluorobenzyl)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 95); 2-amino-7-(3-chlorobenzyl)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 97); 2-amino-7-(3,4-dichlorobenzyl)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 98); 3-((2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-6,8-dioxo-1,6,8,9-tetrahydro-7H-purin-7-yl)methyl)benzonitrile (Compound 100); 2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(4-(trifluoromethyl)benzyl)-7,9-dihydro-1H-purine-6,8-dione (Compound 130); 2-amino-7-(cyclopropylmethyl)-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7,9-dihydro-1H-purine-6,8-dione (Compound 134); 2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-isobutyl-7,9-dihydro-1H-purine-6,8-dione (Compound 146); or a pharmaceutically acceptable salt thereof.

6. Compounds having the following structure: 2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one, or a pharmaceutically acceptable salt thereof.

7. Compounds having the following structure: 2-amino-9-((2R,3R,5S)-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, or a pharmaceutically acceptable salt thereof.

8. Compounds having the following structure: 2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-8H-purin-8-one, or a pharmaceutically acceptable salt thereof.

9. Compounds having the following structure: 2-amino-9-((2R,3S,4S,5R)-4-fluoro-3-hydroxy-5-(hydroxymethyl)tetrahydrofuran--2-yl)-7-(prop-2-yn-1-yl)-7,9-dihydro-1H-purine-6,8-dione, or a pharmaceutically acceptable salt thereof.

10. A pharmaceutical composition comprising the compound according to any one of claims 1 to 9, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable excipient.

11. The pharmaceutical composition of claim 10, further comprising one or more agents, wherein the one or more agents are each independently an immune checkpoint inhibitor, an OX40 agonist, a 4-1BB agonist, an ICOS agonist, a GITR agonist, or an IL2-receptor agonist.

12. The pharmaceutical composition of claim 11, wherein the one or more agents are each independently an inhibitor of PD-1, PD-L1, CTLA4, TIM3, LAG3, SIRPα or CD47.

13. The pharmaceutical composition of claim 10, further comprising one or more agents, wherein the one or more agents are each independently an antibody mediated by ADCC.

14. The pharmaceutical composition of claim 13, wherein the antibody is independently rituximab, trastuzumab or alemtuzumab.

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