Synthesis of heterocyclic compounds. XXXIX. Synthesis of 5‐cyano‐2‐phenyl‐4‐thioxo‐3,4‐dihydropyrimidines

Abstract

Abstract The reaction of thiobenzamide with 3‐alkoxy‐3‐aryl(or alkyl)‐2‐cyanopropenenitriles 1 and sodium 2‐propoxide in 2‐propanol afforded after acidic treatment 6‐aryl(or alkyl)‐5‐cyano‐2‐phenyl‐4‐thioxo‐3,4‐dihydropyrimidines 3 through formation of the 3‐aryl(or alkyl)‐2‐cyano‐3‐thiobenzamidopropenenitrile 2 that has been isolated in one case ( 2a , R 1 = Ph).