To a solution of NaH (sodium hydride, 60% dispersion, 86.0 mg, 2.15 mmol)) in anhydrous THF (20 mL) is added dropwise the solution of 2-(2-isopropoxy-3-methyl-benzoylamino)-indan-2-carboxylic acid ethyl ester (6) (410 mg, 1.07 mmol) in THF (5 mL) at 0° C. After stirring for 20 min, methyl iodide (452 μL, 7.26 mmol) is added dropwise and the resulting suspension is warmed up to RT and continued stirring overnight. After being quenched by saturated aqueous solution of ammonium chloride (5 mL), the reaction mixture is diluted in EtOAc (50 mL). The organic layer is separated, washed with water (1×5 mL) and brine (2×5 mL), dried over anhydrous Na2SO4 and concentrated in in vacuo. The residue is purified by flash column chromatography (115 g silica gel, gradient elution: 0%-30% EtOAc in heptane) to give the pure product (118) as a colorless oil (240 mg, 57%).
