Benzimidazole compound crystal
A novel crystal of (R)-2-[[[3-methyl-4-(2,2,2-trifluoroethoxy)-2-pyridinyl]methyl]sulfinyl]-1H-benzimidazole or a salt thereof of the present invention is useful for an excellent antiulcer agent.
1. A method for producing a crystal of a compound of (R)-2-[[[3-methyl-4-(2,2,2-trifluoroethoxy)-2-pyridinyl]methyl]sulfinyl]-1H-benzimidazole or salt thereof or a hydrate thereof, which comprises:
subjecting a racemate of the compound of 2-[[[3-4-(2,2,2-trifluoroethoxy)-2-pyridinyl]methyl]sulfinyl]-1H-benzimidazole to an optical resolution so as to obtain (R)-2-[[[3-4-(2,2,2-trifluoroethoxy)-2-pyridinyl]methyl]sulfinyl]-1H-benzimidazole as in an amorphous form;
dissolving the compound in the amorphous form in a solvent so as to obtain a solution of (R)-2-[[[3-4-(2,2,2-trifluoroethoxy)-2-pyridinyl]methyl]sulfinyl]-1H-benzimidazole dissolved in the solvent;
concentrating the solution or adding water to the solution so as to crystallize (R)-2-[[[3-4-(2,2,2-trifluoroethoxy)-2-pyridinyl]methyl]sulfinyl]-1H-benzimidazole; and
isolating a crystal of (R)-2-[[[3-4-(2,2,2-trifluoroethoxy)-2-pyridinyl]methyl]sulfinyl]-1H-benzimidazole from the solution or the solution to which the water is added,
wherein the solvent is at least one solvent selected from the group consisting of acetonitrile, acetone, and water, and
(i) if the solvent is acetonitrile, the solvent is gradually evaporated at room temperature for the crystallization of the compound, whereby the crystal of the compound is produced,
(ii) if the solvent is acetone, water is added to the solution for the crystallization of the compound, whereby the crystal of the compound is produced, and
(iii) if the solvent is ethanol, water is added to the solution for the crystallization of the compound, whereby the crystal of the hydrate of the compound is produced.
2. The method according to claim 1 , wherein the optical resolution is carried out by using a chiral column.