Synthesis and Conformational Analysis of a Locked Analogue of Carbovir Built on a Bicyclo[3.1.0]-hex-2-enyl Template

Abstract

The synthesis and biological evaluation of a carbovir analogue (5) built on a bicyclo[3.1.0]hex-2-enyl template is described. A conformational analysis using density functional theory at the B3LYP/6-31G* level has been carried out on the rigid pseudosugar template of 5, the cyclopentene moiety of carbovir and the bicyclo[3.1.0]hex-2-yl pseudosugars of two isomeric carbonucleosides (12 and 13) containing exo- and endo-fused cyclopropane rings. The results show that while the planar configuration of the fused cyclopentane ring of compound 5 helps retain weak anti-HIV activity, the ability of the cyclopentene ring of carbovir to easily adopt a planar or puckered conformation with little energy penalty may prove to be a crucial advantage. The bicyclo[3.1.0]hex-2-yl nucleosides 12 and 13 that were inactive against HIV exhibited stiffer resistance to having a planar, fused cyclopentane moiety.     

Carbovir: A Carbocyclic Nucleoside with Potent and Selective Activity Against Human Immunodeficiency Virus (HIV) in Vitro

Abstract

Carbocyclic 2′, 3′-didehydro-2′,3′-dideoxyquanosine (carbovir), a novel nucleoside analog, emerged as a potent and selective anti-HIV agent from a primary screen of a large number of carbocyclic nucleosides.¹ Carbovir inhibited the infectivity and replication of HIV in T-cells at concentrations 200 to 400-fold below toxicity to host cells. Carbovir was also evaluated for its Inhibitory effects on the expression of viral antigen in HIV-infected CEM cells. Production of p 24 core antigen at optimal inhibitory concentrations of the antiviral agents indicated comparable results for AZT, ddA and carbovir.     

Comparative aspects of adenylic acid deaminase and aspartate-2-oxoglutarate aminotransferase.

1. The content of adenylic acid deaminase and of aspartate-2-oxoglutarate aminotransferase of skeletal muscle tissue from a variety of animals has been determined. 2. White (fast) muscle contained large amounts of adenylic acid deaminase and red (slow) muscle contained large amounts of aspartate aminotransferase. There was a general inverse relationship between the adenylic acid deaminase and the aspartate aminotransferase content of muscles from various vertebrates. Thus, there is no simple correlation between the capacity to produce inosinic acid and ammonia from adenylic acid and the capacity to catalyse the formation of aspartate for conversion of inosinic acid back to adenylic acid. 3. The absence of adenylic acid deaminase from the tail muscles of the yabbie and other invertebrates indicates a marked difference in the Animal Kingdom.     

Short Synthesis and Antiviral Activity of Acyclic Phosphonic Acid Nucleoside Analogues

An efficient route for synthesizing novel allylic and cyclopropanoid phosphonic acid nucleoside analogues is described. The condensation of the bromine derivatives 6 and 18 with nucleoside bases (A, U, T, C, G) under standard nucleophilic substitution and deprotection conditions, afforded the target phosphonic acid nucleoside analogues. These compounds were evaluated for their antiviral properties against various viruses. Cyclopropanoid phosphonic adenine nucleoside analogue 23 showed significant anti-HIV activity.     

Anti-HIV Derivatives of 1-(2,3-Dideoxy-3-N-hydroxyamino-β-D-threo-pentofuranosyl)thymine

Abstract

Representative examples of the title compounds including bicyclic analogs (7–9) in which a perhydro-1,3-oxazine is ortho-fused to the furanose ring, have been prepared in good to excellent yields. Compounds 5 and 7 showed marked activity against HIV-1 and HIV-2 replication in CEM cells (50% inhibitory concentration: 0.80–4.3μg/mL). Their di-O-acetylated (6) and mono-O-acetylated (8) derivatives were considerably less effective. To the best of our knowledge, these β-D-threo anti-HIV nucleoside analogs constitute the first examples of anti-HIV active nucleosides bearing this configuration.     

Synthesis of purine bases having a di(hydroxymethyl)cyclopentenyl group by means of high-pressure reaction and their anti-HIV activity.

The 1'- and 5'-hydroxymethyl derivatives of carbovir and related purine derivatives were synthesized from 5-hydroxymethylcyclopentadiene. The anti-HIV activity evaluation of these compounds has revealed that 9-(c-4,t-5-dihydroxymethylcyclopent-2-en-r-1-yl)-9H-adenine is a prospective chemotherapeutic agent against AIDS.     

Nucleotide,nucleoside and base nutritional requirements of the mosquito Culex pipiens

Nucleic acid subcomponents needed to satisfy the dietary nucleic acid requirement of Culex pipiens were studied in growth experiments using synthetic media in which nucleosides, bases and alternative nucleotides were variously substituted in mixtures of 3 nucleotides (adenylic acid, thymidylic acid, and either cytidylic or uridylic acid) previously shown to be adequate replacements for whole nucleic acid. Any or all 3 nucleotides could be replaced by corresponding nucleosides without adverse effect, except that adenosine substitution moderately delayed pupation. All base substitutions were unsatisfactory: substitution of thymine for thymidylic acid allowed development to the adult stage but at a greatly reduced rate; single substitution of adenine, cytosine or uracil for the corresponding nucleotides allowed scarcely more development than in the total absence of nucleic acid derivatives. Inosinic acid or inosine were adequate substitutes for adenylic acid, but orotic acid or orotidine were ineffective in place of the pyrimidine ribonucleotides, cytidylic or uridylic acids. Deoxyadenylic acid could take the place of adenylic acid, though inefficiently, but deoxycytidylic and deoxyuridylic acids were very poor replacements for the corresponding ribonucleotides. The minimal required nucleic acid derivatives thus appear to be a purine ribonucleotide (adenylic or inosinic acids), a pyrimidine ribonucleoside (either uridine or cytidine), and the pyrimidine deoxyribonucleoside, thymidine.     

The First Synthesis of 4′-Branched 5′-Deoxycarbocyclic 9-Deazaadenosine and Phosphonic Acids as Antiviral Agents

The first synthetic route to 4′-trifluoromethylated 5′-deoxycarbocyclic-9-deazaadenosine analog and its phosphonic acid derivatives was described from α-trifluoromethyl-α,β-unsaturated ester. The C–C bond connection between cyclopentane and base moiety was accomplished using Knoevenagel type condensation from ketone derivative 11. Synthesized nucleoside and phosphonic acid analogs were tested for anti-HIV activity as well as cytotoxicity.     

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,In Vitro Biological Stability,and Anti-HIV Activity of 5-Halo (or Methoxy)-6-Alkoxy (Azido or Hydroxy)-5,6-Dihydro-2′,3′-Didehydro-3′-Deoxythymidine Diastereomers as Potential Prodrugs of 2′,3′-Didehydro-3′-deoxythymidine (D4T)

Abstract

A new class of 5-halo (or methoxy)-6-alkoxy (azido or hydroxy)-5,6-dihydro-2′,3′-didehydro-3′-deoxythymidines (4–17) were investigated as potential anti-AIDS drugs. These 5,6-dihydro derivatives, which are also potential prodmgs of 2′,3′-didehydro-3′-deoxythymidine (D4T) were designed to have properties which would enhance their duration of action, lipophilicity and cephalic delivery to the central nervous system. The 5,6-dihydro derivatives of D4T (4–15), which differ in configuration at the C-5 and C-6 positions, were synthesized by the regiospecific addition of XR (X = Br, Cl, I; R = OMe, OEt, N₃, OH) to the 5,6-olefinic bond of D4T. These 5,6-disubstituted-5,6-dihydro analogs of D4T are more lipophilic (P = 0.70 – 4.0 range) than D4T (P = 0.12) and are stable to E. coli thymidine phosphorylase. Regeneration of the 5,6-olefinic bond to give D4T, upon incubation of the 5-bromo- and 5-iodo-6-methoxy-5,6-dihydro derivatives (6, 7, 10, 11) with glutathione or a mouse liver soluble enzyme fraction, was extensive (50–95%). The most potent anti-HIV-1 agents, 5-iodo-6-methoxy (10, 11), 5-bromo-6-azido (14, 15) and 5-methoxy-6-hydroxy (16, 17) derivatives of D4T, exhibited anti-HIV activities comparable to D4T.

     

Synthesis and Anti-HIV Activity of Some S-Acyl-2-thioethyl (SATE) Phosphoramidate Derivatives of 3′-Azido-2′,3′-dideoxythymidine

Abstract

The synthesis and in vitro anti-HIV activity of tBuSATE phosphoramidate derivatives of AZT incorporating several methyl-esterified α-aminoacids are reported. The biological evaluation strongly supports the hypothesis that such compounds exert their anti-HIV effects via intracellular delivery of the corresponding 5′-mononucleotide.     

Further studies of the action of methionyl adenylate on chick embryo fibroblasts.

Methionyl adenylate (Met-AMP) inhibits protein synthesis by interacting with methionyl-tRNA synthetase. Addition of 1--3 mM inhibitor to chick embryo fibroblasts rapidly stops protein synthesis and DNA synthesis but not RNA synthesis. These effects can be reversed by renewal of the medium. The extent and reversibility of protein and DNA syntheses depend on the concentration of MetAMP in the cultures, the length of exposure and the cellular density. MetAMP is recognised by several enzymes as substrate and/or as inhibitor. MetAmp is degraded to methionol plus 5'-adenylic acid by 5'-phosphodiesterase. Adenosine deaminase, adenylic acid deaminase and 3':5'-phosphodiesterase cannot use MetAMP as substrate but the last enzyme is inhibited. The presence of MetAMP in cultures provokes a small but reproducible increase in the level of methionyl-tRNA synthetase and 5'-phosphodiesterase.     

Role of Phenylalanine Deaminase and Tyrase in the Lignification of Bamboo

A pronounced increase of the activity of phenylalanine deaminase and tyrase during the lignification of bamboo shoots was observed. With progressing maturation from the basal part to the upper part of immature bamboos the pattern of the activity of the enzymes moved toward the upper part of the tissues, where the most active lignification was taking place, and the amount of cinnamic acid derivatives in the tissues was found to be in good accordance with the activity of the enzymes. l-Phenylalanine-G-¹⁴C and l-tyrosine-G-¹⁴C were both well incorporated into the lignin of bamboos. These results indicate that phenylalanine deaminase and tyrase are synthesized progressively just before the lignification of the bamboos and by the enzymes l-phenylalanine and l-tyrosine are deaminated to cinnamic acid derivatives and incorporated into lignin.     

Synthesis,anti-HIV and anti-oxidant activities of caffeoyl 5,6-anhydroquinic acid derivatives

In our continued research on chlorogenic acid analogues and derivatives with improved bioactivity, we have synthesized some caffeoyl 5,6-anhydroquinic acid derivatives. The 1,7 acetonides of chlorogenic acid (15), and of the mono-caffeoyl 5,6-anhydroquinic acids (7–8) showed appreciable anti-HIV activity. The 3,4-dicaffeoyl 5,6-anhydroquinic acid (12) exhibited an anti-HIV activity twice as that of 3,5-dicaffeoylquinic acid (22). The caffeoyl 5,6-anhydroquinic acid derivatives displayed potent anti-oxidant activities. The mono-caffeoyl 5,6-anhydroquinic acids (10–11) were more than twice stronger than chlorogenic acid (21) on SOD-like activity.     

Design,synthesis and docking study of novel coumarin ligands as potential selective acetylcholinesterase inhibitors

New coumaryl-thiazole derivatives with the acetamide moiety as a linker between the alkyl chains and/or the heterocycle nucleus were synthesized and in vitro tested as acetylcholinesterase (AChE) inhibitors. 2-(diethylamino)-N-(4-(2-oxo-2H-chromen-3-yl)thiazol-2-yl)acetamide (6c, IC₅₀ value of 43?nM) was the best AChE inhibitor with a selectivity index of 4151.16 over BuChE. Kinetic study of AChE inhibition revealed that 6c was a mixed-type inhibitor. Moreover, the result of H4IIE hepatoma cell toxicity assay for 6c showed negligible cell death. Molecular docking studies were also carried out to clarify the inhibition mode of the more active compounds. Best pose of compound 6c is positioned into the active site with the coumarin ring wedged between the residues of the CAS and catalytic triad of AChE. In addition, the coumarin ring is anchored into the gorge of the enzyme by H-bond with Tyr130.     

Synthesis of a Nucleoside Bioconjugate System as a Potential Anti-HIV Agent

Abstract

Synthesis and anti-HIV data for a bioconjugate molecule incorporating a HIV protease inhibitor (A74704) and a HIV RT inhibitor (d4T) are presented.     

Design,synthesis and biological evaluation of 2-aminopyrimidinones and their 6-aza-analogs as a new class of CK2 inhibitors

Abstract

In order to find the new potent CK2 inhibitors the 60 derivatives of 2-aminopyrimidinone and their 6-aza-substituted analogs were synthesized and tested in vitro. Among them, the most efficient inhibitor 2-hydroxy-5-[4-(4-methoxyphehyl)-6-oxo-1,6-dihydropyrimidin-2-ylamino] benzoic acid was identified (IC₅₀?=?1.1?μM). The structure--activity relationship study of newly synthesized derivatives was carried out and their binding mode with adenosine triphosphate-acceptor site of CK2 was proposed.     

Synthesis and Anti-Hiv Activity of 4′-Modified Cyclopentenyl Pyrimidine C-Nucleosides

Novel syntheses of 4′-modified cyclopentenyl pyrimidine C-nucleosides were performed via C-C bond formation using S_N2 alkylation via the key intermediate mesylates 6 and 16, which were prepared from acyclic ketone derivatives. When antiviral evaluation of synthesized compound was performed against various viruses such as HIV-1, HSV-1 and HSV-2, isocytidine analogue 20 showed moderate anti-HIV activity in CEM cell line (EC₅₀ = 13.1 μmol).7     

Exploratory studies on CA-15L,an anti-HIV active HIV-1 capsid fragment

Utilizing overlapping fragment peptide libraries covering the whole sequence of an HIV-1 capsid (CA) protein with the addition of an octa-arginyl moiety, we had previously found several peptides with anti-HIV-1 activity. Herein, among these potent CA fragment peptides, CA-15L was examined because this peptide sequence overlaps with Helix 7, a helix region of the CA protein, which may be important for oligomerization of the CA proteins. A CA-15L surrogate with hydrophilic residues, and its derivatives, in which amino acid sequences are shifted toward the C-terminus by one or more residues, were synthesized and their anti-HIV activity was evaluated. In addition, its derivatives with substitution for the Ser149 residue were synthesized and their anti-HIV activity was evaluated because Ser149 might be phosphorylated in the step of degradation of CA protein oligomers. Several active compounds were found and might become new anti-HIV agents and new tools for elucidation of CA functions.