Cytostatic and antiviral 6-arylpurine ribonucleosides.: Part 7:: Synthesis and evaluation of 6-substituted purine L-ribonucleosides

A series of purine L-ribonucleosides 2a-2i bearing diverse C-substituents (alkyl, aryl, hetaryl or hydroxymethyl) in the position 6 were prepared by Pd-catalyzed cross-coupling reactions of 6-chloro-9-(2,3,5-tri-O-acetyl-beta-L-ribofuranosyl)purine with the corresponding organometallics followed by deprotection. Unlike their D-ribonucleoside enantiomers that possess strong cytostatic and anti-HCV activity, the L-ribonucleosides were inactive except for 6-benzylpurine nucleoside 2h showing moderate anti-HCV effect in replicon assay. A triphosphate of 2h did not inhibit HCV RNA polymerase. (c) 2006 Elsevier Ltd. All rights reserved.