The mixture 2-[3-methyl-2-(2-methyl-propenyl)-benzoylamino]-indan-2-carboxylic acid ethyl ester (134) (283 mg, 0.75 mmol) and KOH (600 mg, 10.7 mmol) is dissolved in EtOH (8 mL) and water (1 mL) under a water bath. The water bath is removed when KOH is completely dissolved and the resulting reaction solution is stirred at RT for 3 h. After concentration in vacuo, the residue is dissolved in water (20 mL) and acidified with conc. HCl until no more white precipitate formed. The precipitate is filtered to give a pure product (135) as white solid (250 mg, 95%).
