Synthesis of Dihydro-1,2,4-triazolo[1,5-<i>a</i>]pyrimidines

Abstract

Several 5,7-diaryl-4,5-dihydro-5-methyl-1,2,4-triazolo[1,5-a]pyrimidines 3a-f and 5,7-diaryl-4,7-dihydro-7-methyl-1,2,4-triazolo[1,5-a]pyrimidines 4a-f were synthesized in high yield from 5-amino-1H-1,2,4-triazole (amitrole) (1) and acetophenones 2 by heating in the presence of zinc chloride and subsequent separation of the isomers.