PURIFICATION METHOD FOR 4'-[[2-N-PROPYL-4-METHYL-6-(1-METHYLBENZIMIDAZOLE-2-YL)-BENZIMIDAZOLE-1-YL]-METHYL]-BIPHENYL-2-CARBOXYLIC ACID

摘要

PROBLEM TO BE SOLVED: To provide a method for obtaining 4'-[[2-n-propyl-4-methyl-6-(1-methylbenzimidazole-2-yl)-benzimidazole-1-yl]-methyl]-biphenyl-2-carboxylic acid with high purity.SOLUTION: A method for purifying a compound of formula (1) below includes: a dissolution process of dissolving a crude substance of 4'-[[2-n-propyl-4-methyl-6-(1-methylbenzimidazol-2-yl)-benzimidazole-1-yl]-methyl]-biphenyl-2-carboxylic acid in a mixed solvent of water and a 2-12C alcohol by adding 2.0 to 30.0 mol of ammonia per mol of a composition of formula (1) below; a crystallization process of depositing an ammonium salt of the composition of formula (1) below by discharging ammonia from the solvent obtained in the process; and a process of separating and drying the ammonium salt.