Cytostatic and Antiviral 6-Arylpurine Ribonucleosides IX. Synthesis and Evaluation of 6-Substituted 3-Deazapurine Ribonucleosides

Abstract

A series of 3-deazapurine ribonucleosides 5a-5l bearing diverse C-substituents (alkyl, aryl and heteroaryl) in the position 6 were prepared by Pd-catalyzed cross-coupling reactions of either free 6-chloro-3-deazapurine ribonucleoside 4 or its acetyl protected congener 3 followed by deprotection. An improved synthesis of the starting 4-chloro-1-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-1H-imidazo[4,5-c]pyridine (3) was developed by the application of Vorbrüggen glycosylation of silylated nucleobase with 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose (2). None of compounds 5a-5l showed any considerable cytostatic or antiviral activity.