N-Ethyl-diisopropylamine (2.5 eq.) and 2-methylbenzoyl chloride (1.2 equiv.) were added to an ice-cold solution of (3R)-3-amino-2,3-dihydro-1H-indene-5-carboxylic acid methyl ester hydrochloride (A-03 HCl) (0.88 mmol, 1 equiv.) in methylene chloride at 0° C. under an inert atmosphere and the mixture was then stirred at room temperature for 2 d. The reaction mixture was diluted with ethyl acetate and the organic phase was washed with 10% NH4Cl solution, sat. NaHCO3 solution and sat. NaCl solution. The organic phase was dried over Na2SO4 and concentrated to obtain the crude product, which was purified by column chromatography (silica, cyclohexane/ethyl acetate 4:1). Yield: 70%
