Synthesis of N 6-Substituted 3′-Ureidoadenosine Derivatives as Highly Potent Agonists at the Mutant A3 Adenosine Receptor

Several N ⁶ -substituted 3 ′-ureidoadenosine derivatives were efficiently synthesized starting from D-glucose for the development of H272E mutant A ₃ adenosine receptor (AR) agonists. Among compounds tested, 3 ′-ureido-N ⁶ -(3-iodobenzyl)adenosine ( 2c ) exhibited the highest binding affinity (K _i = 0.22 μ M) at the H272E mutant A ₃ AR without binding to the natural A ₃ AR.     

Design and Synthesis of A3 Adenosine Receptor Ligands, 3′-Fluoro Analogues of Cl-IB-MECA

Abstract

Synthesis of 3′-deoxy-3′-fluoro-N ⁶-substituted adenosines as bioisosteres of Cl-IB-MECA and their binding affinities to A₃ adenosine receptor are described.     

Lead Optimization of N 6-Cyclopentyl-3′-amido-3′-deoxyxylofuranosyladenines as Adenosine A1 Receptor Antagonists

Abstract

Strategies toward the further lead optimization of N ⁶-cyclopentyl-3′-amido-3′-deoxyxylofuranosyladenosines as adenosine A₁ receptor antagonists including the synthesis of the 5′-deoxy-analogues and a practical method for parallel amidation are presented.     

Synthesis of 3′-Trifluoromethyl Nucleosides as Potential Antiviral Agents

Abstract

1,2-Di-O-acetyl-3-deoxy-3-trifluoromethyl-5-O-benzoyl-β-D-riboruranose was synthesized from the precursor keto sugar by the use of Ruppert's reagent (CF₃SiMe₃) as the source of a nucleophilic trifluoromethyl group. Coupling of this trifluoromethyl sugar with nucleobases and elaboration gave novel deoxy and dideoxynucleosides. A single crystal X-ray analysis confirmed the structure and stereochemistry. The deoxynucleosides were converted through an elimination reaction to their dideoxydidehydro derivatives.     

Synthesis of 3′-N-Substituted 3′-Amino-3′-Deoxythymidine Derivatives

Abstract

A series of 3′-N-substituted 3′-amino-3′-deoxythymidine derivatives with alkyl, alkenyl and alkylaryl substituents was synthesized by two methods. The first method involved the reaction of 1-(2,3-dideoxy-3-0-mesyl-5-0-trityl-β-D-threo-pentofuranosyl)thymine with an appropriate amine. In the second method, 3′-amino-5′-0-trityl-3′-deoxy-thymidine served as a synthetic precursor which was reacted with an appropiate aldehyde or ketone followed by sodium borohydride reduction. An improved synthesis of 3′-amino-3′-deoxythymidine from 3′ -azido-5′-0-trityl-3′-deoxythymidine using sodium borohydride was also described.     

Synthesis and Transmembrane Transport Studies of Lipophilic Adenosine 5′-Triphosphate Derivatives

Abstract

The preparation of acyl adenosine 5′-triphosphates as potential membrane permeable prodrugs is presented. The interaction of myristoyl- and cholesteryloxy-carbonyl-ATP with liposomes as model membranes and the release of ATP inside these vesicles was investigated using an enzymatic assay as well as ³¹P-NMR spectroscopy.     

Synthesis of 1′-Deoxypsicofuranosyl-deoxynucleosides as Potential Anti-HIV Agents

Abstract

Various routes to the targets 1, 2, 3, 1-deoxy-psicofuranosyl nucleoside analogues related to anti-HIV agents, are reported. Two routes afforded their 6′-benzylated derivatives 9, 10 and 15. Only the epoxide 12 and deoxynucleosides 19 and 22 were able to be deprotected leading in the first case to 16 and its ring opening derivative 17 and in the second case to 20 and to the target 3.     

Synthesis of 2′,3′-Dideoxy-2′-Fluoro-l-threo-Pentofuranosyl Nucleosides as Potential Antiviral Agents

Abstract

A series of 2′,3′-dideoxy-2′-fluoro-L-threo-pentofuranosyl nucleosides has been synthesized as potential antiviral agents. The synthesized compounds were evaluated against HIV-1, HBV, HSV-1, and HSV-2. Among the synthesized analogues, only the cytosine derivative showed moderate antiviral activity against HIV and HBV.     

Synthesis of 2′,3′-Dideoxy-3′-C-Hydroxymethyl Nucleosides Having the L-Configuration as Potential Inhibitors of HIV

Abstract

Synthesis of 2′,3′-Dideoxy-3′-C-(hydroxymethyl)-α- and β-L-erythro-pentofuranosyl nucleosides of thymine, cytosine and adenine is reported.     

Synthesis of 2′,3′-Dideoxy- and 3′-Azido-2′,3′-dideoxy-pyridazine Nucleosides as Potential Antiviral Agents

Abstract

The synthesis of 4-methoxy-, 4-amino-3-chloro-, and 4-amino-1-(2,3-dideoxy-B-D-glycero-pentofuranosyl)pyridazin-6-one nucleosides, 6,19 and 20 is described. The synthesis of 3,4-dichloropyridazin-6-one (10) was accomplished in 44% overall yield using bromomaleic anhydride (17) as the starting material. The condensation of the silylated base of 10 with the halogenose 12 in the presence of trimethylsilyl triflate as a catalyst afforded a mixture of3,4-dichloro-1-(3,5-di-O-p-toluoyl-2-deoxy-B-D-erythro-pentofuranosyl)pyrridazin-6-one (13) in 67% and its α-anomer 14 in 12% yield, respectively. A series of 3′-sulfonate esters were prepared to explore the synthesis of 3-chloro-4-hydroxy-1-(3-azido-2,3-dideoxy-B-D-erythro-pentofuranosyl) pyridazin-6-one (32) via 6,3-anhydronucleoside analogues. Compounds 15, 19 and 20 were evaluated against human immunodeficiency virus, human cytomegalovirus, and herpes simplex virus type 1 but were inactive.     

Inhibitors of Adenosine Deaminase: Synthesis of Coformycin and 3′-Deoxycoformycin

Abstract

Glycosylation of the heterocycle, 6,7-dihydro-imidazo [4,5-d] [1,3] diazepin-8(3H)-one, with suitably protected sugars under the influence of Lewis acid catalysts gave the β-D-ribo- and 3′-deoxy-β-D-erythropento-furanosyl nucleosides. Deprotection and reduction of the keto nucleosides with sodium borohydride gave the (8R)- and (8S)-3-β-D-glycofuranosyl-3,6,7,8-tetrahydroimidazo [4,5-d]-[1,3] diazepin-8-ols, the (8R)-isomers of which are potent inhibitors of adenosine deaminase.     

Synthesis,In Vitro Anti-HIV Activity,and Biological Stability of 5′-O-Myristoyl Analogue Derivatives of 3′-Fluoro-2′,3′-Dideoxythymidine (FLT) as Potential Bifunctional Prodrugs of FLT

Abstract

A group of 5′-O-myristoyl analogue derivatives of FLT (2) were evaluated as potential anti-HIV agents that were designed to serve as prodrugs to FLT. 3′-Fluoro-2′,3′-dideoxy-5′-O-(12-methoxydodecanoyl)thymidine (4) (EC₅₀ = 3.8 nM) and 3′-fluoro-2′,3′-dideoxy-5′-O-(12-azidododecanoyl)thymidine (8) (EC₅₀ = 2.8 nM) were the most effective anti-HIV-1 agents. There was a linear correlation between Log P and HPLC Log retention time for the 5 ′-O-FLT esters. The in vitro enzymatic hydrolysis half-life (t½), among the group of esters (3–8) in porcine liver esterase, rat plasma and rat brain homogenate was longer for 3′-fluoro-2′,3′-dideoxy-5 ′-O-(myristoyl)thymidine (7), with t½ values of 20.3, 4.6 and 17.5 min, respectively.     

A Novel Class of 4′-Aza Analogues of 2′,3′-Dideoxynucleosides as Potential Anti-HIV Drugs

Abstract

The 1,3 dipolar cycloaddition approach represents the most valuable strategy for the preparation of isoxazolidine nucleosides. The latter posses more conformational degrees of freedom than the corresponding dideoxyribosides. Side reactions due to the presence of formaldehyde in the reaction media can be avoided by proper derivatization of the vinyl-nucleobase.     

Synthesis of 3′,4′-C-Bishydroxymethyl-2′,3′,4′-trideoxy-β-L-threo-pentopyranosyl Nucleosides as Potential Inhibitors of HIV

Abstract

The synthesis of 3′,4′-bishydroxymethyl-2′,3′,4′-trideoxy pentopyranosyl derivatives of thymine, uracil, cytosine, and adenine is described. trans-(3S,4S)-Bis(methoxycarbonyl)cyclopentanone (3) was converted to 1-O-acetyl-3,4-C-bis[(tert-butyldiphenylsiloxy)methyl]-2,3,4-trideoxy-α,β-L-threo-pentopyranose (6), which was subsequently condensed with the silylated purine and pyrimidine bases.     

Synthesis of 5′-Deoxy-5′-nucleosideacetic Acid Derivatives

Abstract

The synthesis of several new 5′-deoxy-5′-nucleosideacetic acid derivatives by the reactions of alkoxycarbonylmethylene triphenylphosphoranes with nucleoside 5′-aldehydes is described.     

4-Substituted Uridine 5′-Triphosphates as Agonists of the P2Y2 Purinergic Receptor

Abstract

Uridine 5′-O-triphosphate (UTP) is a potent agonist of the purinergic receptor designated P_2Y2. UTP is rapidly metabolized in human tissue. To find a compound with similar activity that may be more slowly metabolized, a series of 4-substituted uridine 5′-triphosphates were prepared and evaluated in a P_2Y2 receptor second messenger assay.     

Synthesis of 2′-Deoxyribonucleoside Derivatives of 1-Deazapurine

Abstract

5, 7-Dichloro-3H-imidazo[4, 5-b]pyridine (4) is a versatile base which can be coupled with a variety of sugar moieties and transformed in a series of 7-alkyl(aryl)amino-derivatives by reacting with the corresponding amines. In this paper synthesis, structure elucidation and ADA inhibitory activity of 2′-deoxyribonucleoside derivatives of N⁶-substituted 1-deazaapurines are described.     

New Dinucleoside Phosphonate Derivatives as Prodrugs of 3′-Azido-3′-Deoxythymidine and β-L-2′,3′-Dideoxy-3′-Thiacytidine: Synthesis and Anti-HIV Properties

New phosphonate homodimers of 3′-azido-3′-deoxythymidine (AZT) and a phosphonate heterodimer of β-L-2′,3′-dideoxy-3′-thiacytidine (3TC) and AZT were synthesized. The compounds demonstrated moderate anti-HIV activity. Stability of the compounds in human blood serum was studied. A correlation between anti-HIV activity and stability was defined.     

Synthesis of 3′-O-Propargylthymidine as a Candidate Antiretroviral Agent

Abstract

3′-O-Propargylthymidinc, which may be viewed as a stnictural analogue of the potent antiretroviral agent 3′-azido-3′-deoxythymidine (AZT), was synthesized from 5′-O-(4,4′-dimethoxytritylthymidine by reaction with propargyl bromide followed by gentle acidolysis. The 3′-O-propargyl derivative was tested for antiretroviral activity in SC-1 mouse fibroblasts infected with Rauscher murine leukemia virus (MuLV). No inhibition of MuLV proliferation was observed at concentrations of 3′-O-propargylthymidine from 0.001 to 100 μM. whereas the IC₅₀ against the host cells was 30 μM. By comparison, AZT had an IC₅₀ for MuLV growth of 0.01 μM and an IC₅₀ for cell growth of >100 μM. Thus, replacement of the 3′-N-N≡N group in AZT by a 3′-OCH₂C≡CH group increased cytotoxicity but decreased antiretroviral activity relative to AZT.     

Synthesis and evaluation of sulfonylethyl-containing phosphotriesters of 3′-azido-3′-deoxythymidine as anticancer prodrugs

A series of bis(sulfonylethyl) and mono(sulfonylethyl) phenyl phosphotriesters of zidovudine (3′-azido-3′-deoxythymidine, AZT) were synthesized as potential anticancer prodrugs that liberate AZT monophosphate via nonenzymatic β-elimination mechanism. Stability studies demonstrated that all the synthesized prodrugs spontaneously liberate AZT monophosphate with half-lives in the range of 0.07–278.8 h under model physiological conditions in 0.1 M phosphate buffer at pH 7.4 and 37 °C. Analogous to aldophosphamide, the elimination rates were accelerated in the presence of reconstituted human plasma under the same conditions. Among the compounds, 3, 4, 8, and 10 were comparable or superior to AZT against five established human cancerous cell lines in vitro. Moreover, the selected compounds were equally sensitive to both the wild-type osteosarcoma 143B and the thymidine kinase-deficient 143B/TK⁻ cell lines. The findings are consistent with that these compounds deliver AZT monophosphate intracellularly.