4-(Methylsulfonyl)piperazin-1-ium chloride

In the title molecular salt, C5H13N2O2S+·Cl−, the complete cation is generated by crystallographic mirror symmetry, with both N atoms, the S atom and one C atom lying on the reflecting plane. The chloride ion also lies on the mirror plane. The piperazinium ring adopts a chair conformation and the N—S bond adopts an equatorial orientation. In the crystal structure, the component ions are linked into a three-dimensional framework by intermolecular N—H⋯Cl and C—H⋯Cl hydrogen bonds.

In the title molecular salt, C 5 H 13 N 2 O 2 S + ÁCl À , the complete cation is generated by crystallographic mirror symmetry, with both N atoms, the S atom and one C atom lying on the reflecting plane. The chloride ion also lies on the mirror plane. The piperazinium ring adopts a chair conformation and the N-S bond adopts an equatorial orientation. In the crystal structure, the component ions are linked into a threedimensional framework by intermolecular N-HÁ Á ÁCl and C-HÁ Á ÁCl hydrogen bonds.

Comment
Piperazines are among the most important building blocks in today's drug discovery. The piperazine nucleus is capable of binding to multiple receptors with high affinity and therefore piperazine has been classified as a privileged structure (Dinsmore & Beshore, 2002). They are found in biologically active compounds across a number of different therapeutic areas (Berkheij et al., 2005) such as antifungal, antibacterial, antimalarial, antipsychotic, antidepressant and antitumour activity against colon, prostate, breast, lung and leukemia tumors (Humle & Cherrier, 1999). The piperazines are a broad class of chemical compounds, many with important pharmacological properties, which contain a core piperazine functional group. zhydryl-4-(4-chlorophenylsulfonyl) piperazine (Girisha et al., 2008) have been reported. In view of the importance of the title compound, this paper reports its crystal structure.

Experimental
The title compound was obtained as a gift sample from R. L. Fine Chem., Bangalore, India. The compound was used without further purification. Colourless plates of (I) were obtained from slow evaporation of a methanol solution (m.p.: 489-492 K).

Refinement
All H atoms were located in a difference Fourier map and refined freely. Fig. 1. The molecular structure of (I) with 50% probability ellipsoids for the non-H atoms. Atoms with suffix A are generated by the symmetry operation (x, 1/2 -y, z).

Special details
Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.