PROCESS FOR PRODUCING CRYSTALS OF POLYMORPHIC 2-(3-CYANO-4-ISOBUTYLOXYPHENYL)-4-METHYL-5-THIAZOLECABOXYLIC ACID BY POOR-SOLVENT ADDITION METHOD

摘要

Disclosed is a process for producing A-form crystals of 2-(3-cyamo-4-isobutytoxyphenyl)-4-methyl-5-thiazotecarboxylic acid, comprising: a step of dissolving by heating 2-(3-cyano-4-isobutyloxyphenyl)-4-methyl-5-thiazolecarboxylic acid in one or a plurality of solvents as a good solvent, selected from the group consisting of 1-propmol, 2-propanol, ethanol, and acetone, a step of cooling the solution; and a step of adding to the solution a hydrocarbon solvent as a poor solvent.