Process for preparing polymorphs B and C of 1-{2,4- dichloro -B- {(7-chlorobenzo (6) thien-3-YL) methoxy) phen- ethyl) imidazole) mononitrate

摘要

Two new polymorphs, designated Polymorph B and Polymorph C, of 1-(2,4-dichloro-beta -((7-chlorobenzo (b) thien-3-yl) methoxy) phenethyl) imidazole mononitrate (I) are claimed. Polymorph B is obtd. by dissolving the known Polymorph A in absolute ethanol at reflux, filtering the hot soln., crystallising at ambient temp. and filtering; it has m.pt. 163-164[deg]C. Polymorph C is obtd. as for B but by dissolving in CHCl3 at reflux; it has m.pt. 164.5-165.5[deg]C. Polymorphs B and C are also characterised by IR spectra, differential scanning calorimetry data and X-ray diffraction patterns given in the specification.