| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for easily producing a crystal of a high-purity (5-methyl-2-oxo-1,3-dioxolene-yl)methyl 4-(1-hydroxy-1-methylethyl)-2-propyl-1-[2'-(1H-tetrazole-5-yl)biphenyl-4-ylmethyl]imidazole-5-carboxylate in which the content of low polar impurities derived from olmesartan is reduced.SOLUTION: There is provided a method of carrying out a deprotection reaction of 4-(1-hydroxy-1-methylethyl)-2-propyl-1-{4-[2-(trimethyltetrazole-5-yl)phenyl]phenyl}methylimidazole-5-carboxylic acid(5-methyl-2-oxo-1,3-dioxolene-4-yl)methylester in an acid aqueous solution having a pKa of 2.5 to 6.0 at a temperature of 30 to 45°C. |
