Synthesis of Polysubstituted Pyrimidines from Ketene Dithioacetals Using KF/Al2O3Catalyst

KF/Al2O3 was first used to catalyze the synthesis of 2-alkylthio-4- amino-5-cyano-6-methylthiopyrimidines 3a–f via the reaction of the ketene dithioacetals 1 (prepared from malononitrile) with isothiuronium salts 2a–f. Six pyrimidine compounds were prepared and all of their structures were confirmed by elemental analysis, 1H NMR, and IR. The reaction conditions (solvents, catalyst amounts, and temperature) were investigated for the first time. The separation yield reached 89%.