Synthesis of 2-imino-7-methyl-2,3-dihydroimidazo[1,2-a]pyrimidin-5(1H)-ones and their reactions with nucleophiles

摘要

[2-Alkylthio-6-methyl-4-oxopyrimidin-3(4H)-yl]acetonitriles (3-5) treated with sodium methoxide in methanol followed by ammonium chloride were cyclized to 2-imino-7-methyl-2,3-dihydroimidazo[1,2-a]pyrimidin-5(1H)-ones (6-8). Under acid or base-catalyzed hydrolysis they were converted to 7-methylimidazo[1,2-alpyrimidine-2,5-[1H,3H]-diones (9-11), whereas in the reaction with butyl- or benzylamine the corresponding 7-methyl-2-(substitutedamino)imidazo[1,2-a]pyrimidin-5(3H)-ones (13-18) were produced. The latter were found to exist in two tautorneric forms in CDCl3 solution.