Synthesis and antiviral activity of new dimeric inhibitors against HIV-1

Development of Triazoles and Triazolium Salts Based on AZT and Their Anti-Viral Activity against HIV-1

We report herein a set of 3'-azido-3'-deoxythymidine (AZT) derivatives based on triazoles and triazolium salts for HIV-1 infection. The compounds were synthesized via click chemistry with Cu(I) and Ru(II) catalysts. Triazolium salts were synthesized by reaction with methyl iodide or methyl triflate in good yields. The antiviral activity of the compounds was tested using two methodologies: In method one the activity was measured on infected cells; in method two a pre-exposure prophylaxis experimental model was employed. For method one the activity of the compounds was moderate, and in general the triazolium salts showed a decreased activity in relation to their triazole precursors. With method two the antiviral activity was higher. All compounds were able to decrease the infection, with two compounds able to clear almost all the infection, while a lower antiviral activity was noted for the triazolium salts. These results suggest that these drugs could play an important role in the development of pre-exposure prophylaxis therapies.

Pyrimidine 2,4-Diones in the Design of New HIV RT Inhibitors

The pyrimidine nucleus is a versatile core in the development of antiretroviral agents. On this basis, a series of pyrimidine-2,4-diones linked to an isoxazolidine nucleus have been synthesized and tested as nucleoside analogs, endowed with potential anti-HIV (human immunodeficiency virus) activity. Compounds 6a-c, characterized by the presence of an ethereal group at C-3, show HIV reverse transcriptase (RT) inhibitor activity in the nanomolar range as well as HIV-infection inhibitor activity in the low micromolar with no toxicity. In the same context, compound 7b shows only a negligible inhibition of RT HIV.

Synthesis and cytotoxic activity of novel acyclic nucleoside analogues with functionality in click chemistry

We describe synthesis of novel acyclic nucleoside analogues which are building blocks for CuAAC reaction and their activity against two types of human cancer cell lines (HeLa, KB). Three of chosen compounds show promising cytotoxic activity. Synthesis pathway starting from simple and easily accessible substrates employing DMT or TBDPS protective groups is described. Adenosine and thymidine analogues containing alkyne moiety and adenosine analogue containing azido group were synthesized. The obtained units showed ability of forming triazole motif under the CuAAC reaction conditions.

Discovery of novel anti-HIV agents via Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click chemistry-based approach

INTRODUCTION

In recent years, a variety of new synthetic methodologies and concepts have been proposed in the search for new pharmaceutical lead structures and optimization. Notably, the Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click chemistry approach has drawn great attention and has become a powerful tool for the generation of privileged medicinal skeletons in the discovery of anti-HIV agents. This is due to the high degree of reliability, complete specificity (chemoselectivity and regioselectivity), mild conditions, and the biocompatibility of the reactants.

AREAS COVERED

Herein, the authors describe the progress thus far on the discovery of novel anti-HIV agents via the CuAAC click chemistry-based approach.

EXPERT OPINION

CuAAC click chemistry is a proven protocol for synthesizing triazole products which could serve as basic pharmacophores, act as replacements of traditional scaffold or substituent modification, be a linker of dual-target or dual-site inhibitors and more for the discovery of novel anti-HIV agents. What's more, it also provides convenience and feasibility for dynamic combinatorial chemistry and in situ screening. It is envisioned that click chemistry will draw more attention and make more contributions in anti-HIV drug discovery in the future.

Alkynylation of steroids via Pd-free Sonogashira coupling

A new biligand catalytic system was applied for the Pd-free Sonogashira syntheses of valuable steroidal enynes.

Synthesis and anti-HIV-1 activity of new fluoro-HEPT analogues: an investigation on fluoro versus hydroxy substituents

Coupling of 6-benzyl-5-hydroxymethyluracil (1) with formaldehyde acetals followed by fluorination using (diethylamino)sulfur trifluoride (DAST) afforded 1-alkenyloxymethyl and 1-propargyloxymethyl 5-fluoromethyl-6-benzyluracils 3a-c. 6-(3,5-Dimethylbenzyl)-5-ethyl-1-[(2-fluoroethoxy)methyl]pyrimidine-2,4(1H,3H)-dione (6) was synthesized by fluorination of the corresponding hydroxy derivative 5. Sonogoshira reaction was performed on 6-(3,5-dimethylbenzyl)-5-ethyl-1-(4-iodobenzyl)uracil (7) with propargyl alcohol to afford 8 which was fluorinated to give the fluoro propargyl derivative 9. Compound 7 was synthesized by N1-alkylation of the corresponding uracil. Significant activity was found against HIV-1 except for compounds with 5-hydroxymethyl and 5-fluoromethyl substituents.