C([O:3][C:4]([C:6]1([NH:15][C:16](=[O:28])[C:17]2[CH:22]=[CH:21][C:20]([O:23][CH:24]([F:26])[F:25])=[CH:19][C:18]=2[CH3:27])[CH2:14][C:13]2[C:8](=[CH:9][CH:10]=[CH:11][CH:12]=2)[CH2:7]1)=[O:5])C.[OH-].[K+].CCO>O>[F:25][CH:24]([F:26])[O:23][C:20]1[CH:21]=[CH:22][C:17]([C:16]([NH:15][C:6]2([C:4]([OH:5])=[O:3])[CH2:14][C:13]3[C:8](=[CH:9][CH:10]=[CH:11][CH:12]=3)[CH2:7]2)=[O:28])=[C:18]([CH3:27])[CH:19]=1The mixture of 2-(4-difluoromethoxy-2-methyl-benzoylamino)-indan-2-carboxylic acid ethyl ester (243) (301 mg, 0.77 mmol), KOH (50% aqueous solution, 1.73 g, 15.5 mmol), EtOH (10 mL) and water (1 mL) are stirred in a 20 mL vial at 50° C. for 30 min. After concentration in vacuo, the residue is dissolved in water (10 mL) and acidified with conc. HCl until no more white precipitate came out of the water. The filtration affords 2-(4-difluoromethoxy-2-methyl-benzoylamino)-indan-2-carboxylic acid (244) as white solid (245 mg, 88%).
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