Research Article: 4-(3-Methyl­anilino)-N-[N-(1-methyl­ethyl)carbamo­yl]pyridinium-3-sulfon­amidate (torasemide T–N): a low temperature redetermination

Date Published: May 01, 2009

Publisher: International Union of Crystallography

Author(s): Gianluca Bartolucci, Bruno Bruni, Silvia A. Coran, Massimo Di Vaira.


The structure [Danilovski et al. (2001 ▶). Croat. Chim. Acta74, 103–120] of the T–N (non-solvated) polymorph of torasemide, C16H20N4O3S, a diuretic drug used in the treatment of hypertension, has been redetermined at low temperature. The zwitterionic form of the mol­ecule is confirmed, although GAUSSIAN03 calculations suggest that this form is less stable in the gas phase. The unit-cell contraction between 298 and 100 K is approximately isotropic and the largest structual change is in a C—N—C—C torsion angle, which differs by 11.4 (3)° between the room-temperature and low-temperature structures. There are two mol­ecules in the asymmetric unit, both of which contain an intra­molecular N—H⋯N hydrogen bond. In the crystal structure, both mol­ecules form inversion dimers linked by pairs of N—H⋯N hydrogen bonds. Further N—H⋯N and N—H⋯O hydrogen bonds lead to a three-dimensional network. The different hydrogen-bond arrangements and packing motifs in the polymorphs of torasemide are discussed in detail.

Partial Text

For the crystal structures of polymorphs of torasemide, see: Dupont et al. (1978 ▶); Danilovski et al. (2001 ▶). For the structure of the water–methanol solvated T–II form of torasemide, see: Bartolucci et al. (2009 ▶).




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