Two hydrates of 6-methoxypurine.

6-Methoxypurine crystallizes from N,N-methylformamide as the hemihydrate, C 6 H 6 N 4 O.0.5H 2 O, and from water as the trihydrate, C 6 H 6 N 4 O.3H 2 O. Both forms crystallize in the triclinic crystal system. Upon heating the trihydrate, molecules of water are liberated successively; the hemihydrate is formed at 383 K. In the hemihydrate, the H atom on the imidazole N atom is disordered between the two N atoms. The water molecule in the hemihydrate and the H atoms of a water molecule in the trihydrate are also disordered. In the hemihydrate, the organic moieties are connected by N-H...N hydrogen bonds, while they are connected via water molecules in the trihydrate.