Synthesis of Polysubstituted Pyrimidines from Ketene Dithioacetals Using KF/Al₂O₃ Catalyst

Abstract

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%.