A monoclinic polymorph of the ticlopidine hydrochloride
Abstract
treat symptoms of allergic conditions such as rhinitis and urticara. In the Cambridge Structural Database (CSD) there is one report for the dextro isomer (REFCODE: CPHMAL10) and three reports in the Powder Diffraction File (PDF-4+: 00-041-1599, 00-042-1792, 00-050-2420). Similarly, there is one report in CSD and five in the PDF-4 for the racemic mixture. In an attempt to obtain polymorphic modifications of DexChlor, crystallization experiments were carried by slow evaporation and vapour diffusion using water, ethanol, methanol, acetone, dichloromethane and DMSO, among other solvents. The crystallization of DexChlor in acetone, by slow evaporation at 4-5 C, produced colourless prisms. The c parameter of the unit cell of this phase is twice the corresponding value for CPHMAL10. The asymmetric unit has two crystallographically independent molecules. The geometry of one of the molecules is such that it overlaps with the molecule obtained in the previous report but the second independent molecule has a different conformation. In the new dataset, the reflections with l=2n+1 are systematically weak but nevertheless present. Transformation of the atomic positions of CPHMAL10 and re-indexing of data in the smaller cell resulted in a non-satisfactory refinement of the structure. This indicated that the small cell does not represent correctly the structure of DexChlor. Thus, DexChlor crystallizes in the monoclinic system, space group P2 1 with unit cell parameters a=8.8872(6), b=20.3157( , =104.032(4), V=2008.5(2) 3, Z=4 . A detailed description will be presented.