Andrzej Piasek

Synthesis and biological activity of 1H-benzotriazole and 1H-benzimidazole analogues - inhibitors of the NTPase/helicase of HCV and of some related Flaviviridae

To improve anti-helical activity of analogues of 1H-benzotriazole and 1H-benzimidazole their N-alkyl derivatives were synthesized and tested for anti-helicase activity against enzymes of selected Flaviviridae including hepatitis C virus (HCV), West Nile virus (WNV), Dengue virus (DENV) and Japanese encephalitis virus (JEV). 1- and 2-alkyl derivatives of 4,5,6,7-tetrabromo-1H-benzotriazole were obtained by direct alkylation of 4,5,6,7-tetrabromo-1H-benzotriazole with the use of respective alkyl halides in the presence of KOH in methanol, to give a mixture of 1- and 2- isomers, which was separated by flash column chromatography in good yield. The proportion of isomers strongly depended on the reaction time and temperature. 1- and 2-hydroxyethyl and 1- and 2-chloroethyl derivatives of the tetrabromobenzo-triazole were synthesized with the use of 2-bromoethanol and 1-bromo-2-chloroethane respectively as alkylating agents. N-alkylation of this benzotriazole compound enhanced inhibitory activity and selectivity towards the helicase activity of HCV NTPase/helicase. The most active were the 2-methyl, 2-ethyl and 2-propyl derivatives (IC50∼6.5 μM in the presence of DNA as a substrate). Derivatives of the benzotriazole in which hydroxyethyl or chloroethyl replaced the alkyl substituents lost their inhibitory activity. Brominated or methylated benzotriazole N(1) ribosides also did not exert helicase inhibitory activity. Although a number of N(1) and N(2) alkyl derivatives exerted good HCV and WNV helicase inhibitory activity when DNA was used as substrate, the activity was strongly decreased or even disappeared when RNA was used as substrate. The cytotoxicity tests in Vero and HeLa Tat cells showed a substantial decrease of cytotoxicity of N-alkyl derivatives as compared to the parent benzotriazole.

Thiated pyrimidine deoxynucleoside analogues, potential chemotherapeutic agents, and substrates/inhibitors in various enzyme systems

Abstract The synthesis of thated nucleoside and nucleotide analogues, and determination of their structures, conformations, potential chemotherapeutic activities, and substratehnhibitor properties in various enzyme systems, with emphasis on enzymes related to chemotherapeutic activities, are reported.

Synthesis, biological properties and anti-HIV-1 activity of new pyrimidine P1,P2-dinucleotides.

New homo- and hetero-P1,P2-dinucleotides were prepared with the use of multistep procedures starting from the monophosphates of 3′-fluoro-2-thiothymidine, 3′-fluoro-4-thiothymidine, AZT and 1-[(2-hydroxyethoxy)-methyl-5-propyl-6-phenylselenenyl]uracil. Anti-HIV properties of the synthesized P1,P2-dinucleotides were evaluated against laboratory syncytia inducing strain HIV-1 in CEM-T4 cells. Anti-HIV activities were in the range of 5–45 nM, and therapeutic indexes were higher than 4666–14000. Interactions of the above mentioned compounds with recombinant HIV-1 reverse transcriptase were also investigated. The obtained results point to reverse transcriptase inhibition, with somewhat lower inhibitory activity than that of their parental nucleoside-5′-triphosphates. Compound 6 may be regarded as a potent anti-HIV/AIDS drug.

Thiated Analogues of 2′,3′-Dideoxy-3′-fluorothymidine and Their Phosphorylated and Phosphonylated Derivatives: Synthesis, Interaction with HIV Reverse Transcriptase, and In Vitro Anti-HIV Activity

The search for new, modified 20,30-dideoxynucleosides, potential reverse transcriptase (RT) inhibitors, is still of special interest; bone marrow toxicity and rapidly developing resistance of currently used nucleosides point to the need for new RT inhibitors. 20,30-Dideoxy-30-fluorothymidine (FLT), a pyrimidine 30-deoxy30-substituted thymidine analogue, is one of the most potent in vitro inhibitors of HIV and its reverse transcriptase, but exhibits hematologic toxicity in vivo. It was previously shown that some 5-substituted 20,30-dideoxyuridine derivatives exhibited more selective anti-HIV activity. It appeared to us that an introduction to FLT of the substituents decreasing the pKa value for dissociation of N(3)-H, and enhancing hydrophobic properties of pyrimidine moiety may affect its inhibitory properties, with improved selectivity. It was therefore of interest to synthesize and to test the activity and cytotoxicity of hydrophobic analogues of FLT, and investigate its

5'-O-Ester prodrugs of potent and selective anti-HIV agent-2', 3'-dideoxy-3'-fluoro-2-thiothymidine (S2FLT): Synthesis and anti-HIV activity

Abstract Novel synthesis of 2′,3′-dideoxy-3′-fluoro-2-thiothymidine (SFLT) based on transformation of appropriately protected 1-β-D-threo-ribofuranosylthymine is presented. The synthesis and evaluation of SFLT 5′-O-ester prodrugs enzymatic hydrolysis, as well as their anti-HIV activity, is also described.