The reactions of the 5-bromo-6-methyl-2',3'-O-isopropylideneuridines 9
and 10 with a number of nucleophiles in hot DMF have been investigate
d. With acetate ion as the nucleophile, either the 5-acetoxy-(11,12) o
r the 6-acetoxymethyl- (15) products can be obtained in modest yield d
epending upon the exact reaction conditions. With nitrogen nucleophile
s (aniline or p-methoxylamine) reaction takes place at the 6-methyl ca
rbon, whereas with sulfur nucleophiles (thiophenol, thioacetate) only
the 5-substituted products are obtained.