Studies on the synthesis of the derivatives of 5-(dihydroxyboryl)-cytosines and -isocytosines

Abstract

Boron derivatives of isocytosine, containing a dihydroxyboryl group in the 5-position, have been prepared for the first time. Reaction of appropriate pyrimidines with n-butyllithium and subsequent boronation at –100 °C with triethylborate, followed by catalytic hydrogenation, gave hydrolytically stable N,N-dimethyl-5-(dihydroxyboryl)isocytosine 8a and N-methyl-5-(dihydroxyboryl)isocytosine 8b. Theoretical calculations suggest that the corresponding boron derivatives of cytosine cannot be obtained as thermodynamically stable compounds.