Pyrimidine derivatives and related compounds. Part 36. Nucleophilic addition reaction of a cyanide lon to 6-substituted 1,3-dimethyl-5-nitrouracils. Synthesis of 5,6-dihydrouracil and 5,6-dihydrocyclo-thymine derivatives
Abstract
6-Substituted 1,3-dimethyl-5-nitrouracils (3a–c) react with potassium cyanide to give stereospecifically the 6-cyano-5-nitro-5,6-dihydrouracils (4a–c). Reaction of 6-bromomethyl-1,3-dimethyl-5-nitrouracil (7) with potassium cyanide gives 6-cyano-1,3-dimethyl-5-nitro-5,6-dihydrocyclothymine (8). The structures of the 5,6-dihydrouracils (4a–c) and the cyclothymine (8) were clarified using 1H and 13C n.m.r. spectroscopy.