Synthesis of 2,4-dioxo-, 2-oxo-4-thioxo-, 4-oxo-, and 4-thioxo-pyrimidine-5-carbonitriles
Abstract
Methyl N-methoxycarbonylimidates (1)–(4) cyclized readily with 2-cyanoacetamide (5) or 2-cyanoethanethioamide (6) to 2,4-dioxopyrimidine-5-carbonitriles (7)–(10) or 2-oxo-4-thioxopyrimidine-5-carbonitriles (11) and (12). In analogous reactions with alkyl N-acylimidates (15)–(19) 4-oxo-pyrimidine-5-carbonitriles (20)–(23) or 4-thioxopyrimidine-5-carbonitrile (24) were obtained. Representatives of 4-thioxopyrimidine-5-carbonitriles (11), (24) were methylated to 4-methylthio-pyrimidine-5-carbonitriles (13) and (25) or cyclized with methyl chloroacetate to give methyl thieno[2,3-d]pyrimidine-6-carboxylates (14) and (26)