Epalrestat tetra­hydro­furan monosolvate: crystal structure and phase transition

Acta Crystallographica Section E: Crystallographic Communications

Putra, O.D.¹  Umeda, D.¹  Yonemochi, E.¹  Fukuzawa, K.¹  Gunji, M.¹ 

[1] School of Pharmacy and Pharmaceutical Sciences, Hoshi University, 2-4-41, Ebara, Shinagawa, Tokyo 145-8501, Japan

关键词: CRYSTAL STRUCTURE;    EPALERSTAT;    TETRAHYDROFURAN;    MONOSOLVATE;    HYDROGEN BONDING;   

DOI  :  10.1107/S2056989017007976

学科分类：数学（综合）

来源: International Union of Crystallography

【 摘 要 】

The title compound, epalrestat {systematic name: (5Z)-5-[(2E)-2-methyl-3-phenyl­prop-2-en-1-yl­idene]-4-oxo-2-sulfanyl­idene-1,3-thia­zolidine-3-acetic acid}, crystallized as a tetra­hydro­furan monosolvate, C15H13NO3S2·C4H8O. Epalrestat, an important drug for diabetic neuropathy, has been reported to exist in polymphic, solvated and co-crystal forms. In the mol­ecule reported here, the phenyl ring is inclined to the rhodamine ring by 22.31 (9)°, and the acetic acid group is almost normal to the rhodamine ring, making a dihedral angle of 88.66 (11)°. In the crystal, pairs of O—H⋯O hydrogen bonds are observed between the carb­oxy­lic acid groups of epalerstat mol­ecules, forming inversion dimers with an R22(8) loop. The dimers are linked by pairs of C—H⋯O hydrogen bonds, forming chains along [101]. The solvate mol­ecules are linked to the chain by a C—H⋯O(tetra­hydro­furan) hydrogen bond. A combination of thermal analysis and powder X-ray diffraction revealed that title compound desolvated into epalerstat Form II. One C atom of the tetra­hydro­furan solvate mol­ecule is positionally disordered and has a refined occupancy ratio of 0.527 (18):0.473 (18).

【 授权许可】

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