C6 substitution of inosine using hexamethylphosphorous triamide in conjunction with carbon tetrahalide or N-halosuccinimide

Herein we report the facile conversion of 2′,3′,5′-tri-O-acetylinosine to three different nucleoside analogs via reaction of hexamethylphosphorous triamide and an organic halide. Acetyl-protected 6-bromopurine riboside, 6-chloropurine riboside and N6,N6-dimethyladenosine can each be prepared in good yield from 2′,3′,5′-tri-O-acetylinosine, HMPT and halide. The major product of the reaction is determined by the identity of the halide used and the reaction temperature.