Synthesis and anti-HIV activity of L-β-3′-C-cyano-2′,3′-unsaturated nucleosides and L-3′-C-cyano-3′-deoxyribonucleosides

An efficient synthetic method was developed for L-beta-3'-C-cyano-2',3'-unsaturated nucleosides and L-3'-C-cyano-3'-deoxyribonucleosides. The key intermediate 11 was obtained from L-xylose, from which a series of pyrimidine and purine nucleosides were prepared in high yield by the coupling of 11 and various silyl-protected bases in the presence of TMSOTf. These nucleosides were eliminated, followed by deprotecting to give L-beta-3'-C-cyano-2',3'-unsaturated nucleosides. When selectively deprotected by hydrazine hydrate in buffered acetic acid-pyridine followed by treatment with potassium carbonate in methanol, L-3'-C-cyano-3'-deoxyribonucleosides were obtained. The synthesized nucleosides were tested for anti-HIV activity. (C) 2003 Elsevier Ltd. All rights reserved.