Three new olanzapine structures: the acetic acid monosolvate, and the propan-2-ol and propan-2-one hemisolvate monohydrates.

The crystal structures of three new solvates of olanzapine [systematic name: 2-methyl-4-(4-methylpiperazin-1-yl)-10H-thieno[2,3-b][1,5]benzodiazepine], namely olanzapine acetic acid monosolvate, C17H20N4S·C2H4O2, (I), olanzapine propan-2-ol hemisolvate monohydrate, C17H20N4S·0.5C3H8O·H2O, (II), and olanzapine propan-2-one hemisolvate monohydrate, C17H20N4S·0.5C3H6O·H2O, (III), are presented and compared with other known olanzapine forms. There is a fairly close resemblance of the molecular conformation for all studied analogues. The crystal structures are built up through olanzapine dimers, which are characterized via C-H...π interactions between the aliphatic fragment (1-methylpiperazin-4-yl) and the aromatic fragment (benzene system). All solvent (guest) molecules participate in hydrogen-bonding networks. The crystal packing is sustained via intermolecular N(host)-H···O(guest), O(guest)-H···N(host), O(guest)-H···O(guest) and C(host)-H···O(guest) hydrogen bonds. It should be noted that the solvent propan-2-ol in (II) and propan-2-one in (III) show orientational disorder. The propan-2-ol molecule lies close to a twofold axis, while the propan-2-one molecule resides strictly on a twofold axis through the carbonyl C atom. In both cases, the water molecules present positional disorder of the H atoms.