Ten π -electron nitrogen heterocyclic compounds:X the syntheses and structure determinations of some 1,2,4-triazolopyrimidines

It has been shown that the reaction of 2-hydrazinopyrimidines with ethyl orthoesters yields 1,2,4 -triazolo[4,3 -a]pyrimidines as well as 1,2,4-triazolo[1,5-a]pyrimidines. The structures of the parent compounds and of some methyl derivatives have been established by NMR spectroscopy.