Quetiapine N-oxide–fumaric acid (2/1)

Abstract

The title compound (systematic name: 2-{2-[4-(dibenzo[b,f][1,4]thiazepin-11-yl)piperazin-1-yl 1-oxide]ethoxy}ethanol–fumaric acid (2/1)), C21H25N3O3S·0.5C4H4O4, is one of the oxidation products of quetiapine hemifumaric acid. In the tricyclic fragment, the central thiazepine ring displays a boat conformation and the benzene rings are inclined to each other at a dihedral angle of 72.0 (2)°. The piperazine ring adopts a chair conformation with its ethoxyethanol side chain oriented equatorially. In addition to the main molecule, the asymmetric unit contains one-half molecule of fumaric acid, the complete molecule being generated by inversion symmetry. In the crystal, O—H...O hydrogen bonds link the components into corrugated layers parallel to bc plane.