4,7-Difluoro-2-[3-methyl-2-(2-methyl-propenyl)-benzoylamino]-indan-2-carboxylic acid ethyl ester (391) (133 mg, 0.32 mmol) is dissolved in EtOH (20 mL) and set to stir at RT. To this solution was added 5M KOH (2 ml). The reaction mixture was stirred at RT. After concentration in vacuo, the residue obtained is dissolved in water (20 mL) and washed with EtOAc (20 mL). The phases are separated and the aqueous phase is acidified with concentrated HCl to pH 2. The aqueous phase is washed with 100 mL EtOAc. The organic phases were collected, concentrated to dryness, and then the resulting residue is purified on an HPLC. The desired product (392) is obtained as white solid (38 mg, 28%).
