A convenient and efficient synthesis of new 5-azapurine derivatives was developed. The regioisomeric 5-amino-6, 7-dihydro-and 7-amino-4, 5-dihydro [1, 2, 4] triazolo [1, 5-a][1, 3, 5] triazines were prepared in 3–4 steps from benzhydrazide via complementary and regiospecific routes as a part of our lead finding program. The molecular structures and tautomeric preferences of the compounds obtained were investigated using NMR spectral ...