Two polymorphs of afobazole from powder diffraction data.

Vladimir V Chernyshev, Sanita Petkune, Andris Actins, Raimonds Auzins, Dmitry I Davlyatshin, Pavel V Nosyrev, Yurii A Velikodny

Department of Chemistry, M. V. Lomonosov Moscow State University, Moscow 119991, Russian Federation. vladimir@struct.chem.msu.ru

Acta crystallographica. Section C, Crystal structure communications 2013 Mar

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Afobazole {systematic name: 2-[2-(morpholin-4-yl)ethylsulfanyl]-1H-benzimidazole} is a new anxiolytic drug and Actins, Auzins & Petkune [(2012). Eur. Patent EP10163962] described four polymorphic modifications. In the present study, the crystal structures of two monoclinic polymorphs, 5-ethoxy-2-[2-(morpholin-4-ium-4-yl)ethylsulfanyl]-1H-benzimidazol-3-ium dichloride, C15H23N3O2S(2+)·2Cl(-), (II) and (IV), have been established from laboratory powder diffraction data. The crystal packing and conformation of the dications in (II) and (IV) are different. In (II), there are channels in the [001] direction, which offer atmospheric water molecules an easy way of penetrating into the crystal structure, thus explaining the higher hygroscopicity of (II) compared with (IV).

Citation

Vladimir V Chernyshev, Sanita Petkune, Andris Actins, Raimonds Auzins, Dmitry I Davlyatshin, Pavel V Nosyrev, Yurii A Velikodny. Two polymorphs of afobazole from powder diffraction data. Acta crystallographica. Section C, Crystal structure communications. 2013 Mar;69(Pt 3):299-302