Summary
Purine ribonucleosides bearing various C -substituents at the 6-position have been synthesized in good yields in a few steps from inosine. On reaction with the sodium or lithium salts of such active methylene compounds as malononitrile, methyl cyanoacetate, ethyl malonate, and ethyl acetoacetate, 6-chloro-9- (2′,3′,5′-tri- O -benzoyl-β- D -ribofuranosyl)purine ( 1 ) furnished the corresponding 6-substituted purine analogs ( 2 ), which were debenzoylated with base into the triols ( 3 ) 6-α,α-Dicyanomethylidene-(1 H )-purine derivative ( 2 a) was converted into 3-amino and 3-dimethylamino-2-(9-ribofuranosylpurine-6-yl)acrylonitriles ( 4 and 5 ) by catalytic hydrogenation.