| abstract |
Disclosed is a process for producing A-form crystals of 2-(3-cyano-4-isobutyloxyphenyl)-4-methyl-5-thiazolecarboxylic acid, the process comprising the step of heating and dissolving 2-(3-cyano-4-isobutyloxyphenyl)-4-methyl5-thiazole-carboxylic acid in one or more solvents, as good solvents, selected from a group consisting of 1-propanol, 2-propanol, ethanol, and acetone, the step of cooling the solution, and the step of adding a hydrocarbon solvent as a poor solvent to the cooled solution. |