Abstract Some new 1, 2, 3-triazolo [4, 5-e]-1, 2, 4-triazolo [3, 4-c] pyrimidmes were prepared starting from the corresponding 1, 2, 3-triazolo [4, 5-d] pyrimidines via the formation of the 1, 2, 4-triazole ring. Thus suitable hydrazino derivatives 6 were condensed with triethyl orthoformate, triethyl orthoacetate and triethyl orthobenzoate to give the expected tricyclic derivatives 7, 8 and 9. Intramolecular cyclization of the ethoxycarbonylhydrazino ...