1,3,4-Oxadiazolo[3,2-α]pyrimidinium salts

5-Amino-1,3,4-oxadiazolium perchlorates react with 1,3-carbonyl-functional compounds to give 1,3,4-oxadiazolo3,2-α]pyrimidinium perchlorates. The latter are cleaved by both alkali and strong acid to give 1-amino-2-pyrimidinone or 5-amino-1,3,4-oxadiazole derivatives. The l,3,4-oxadiazolo3,2-α]pyrimidinium perchlorates react with anailine and hydrazines to give sym-triazolo1,5-α]pyrimidinium salts and with acetylacetone to give pyrazolo1,5-α]pyrimidines.