Trifluoromethyl-substituted Di- and Tetrahydroazolopyrimidines

The condensation of 4,4,4-trifluoro-1-phenylbut-1-en-3-one with 2-aminobenzimidazole, 3-amino-1,2,4-triazole, and 5-aminotetrazole gives hydroxy-substituted tetrahydro derivatives of pyrimido[1,2-a]benzimidazole, and of 1,2,4-triazolo-, and tetrazolo[1,5-a]pyrimidine. Dehydration of them to the corresponding dihydroazolopyrimidines has been carried out. An X-ray structural investigation was carried out and the molecular structure of 5-hydroxy-7-phenyl-5-trifluoromethyl-4,5,5,7-tetrahydrotetrazolo[1,5-a]pyrimidine is discussed.