Crystal structures of an antiallergic 8-azapurine (v-triazolo[4,5-d]pyrimidine) and its metal complex, 3-methyl-8-azaxanthine monohydrate and trans-diamminebis(3-methyl-8-azaxanthinato)copper(II) dihydrate

Abstract

X-Ray crystal structure analyses of 3-methyl-8-azaxanthine and its diamminecopper(II) complex show that the free base exists as the N(8) tautomer and the metal complex involves a trans square-planar copper atom co-ordinated by two deprotonated bases through the N(8) site and by two ammine ligands, suggesting that N(8) in the triazole system has considerable basicity.