In anhydrous dichloromethane were dissolved 344 mg (1.23 mmol) of (2S,3S)-N-[(3,4-methylenedioxy)phenyl]-3-amino-2-hydroxyheptanamide, 315 mg (1.23 mmol) of 1-[N-(morpholine-4-carbonyl)amino]cyclohexanecarboxylic acid and 233 mg (1.48 mmol) of 1-hydroxybenzotriazole, and then, under nitrogen stream, 284 mg (1.48 mmol) of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide was added to the above mixture at 0° C. Thereafter, the temperature of the reaction mixture was returned to room temperature, and the mixture was stirred overnight. The reaction mixture was concentrated under reduced pressure, the residue was dissolved in 80 ml of ethyl acetate, and the resulting mixture was washed successively with water, a 10% aqueous potassium hydrogen sulfate solution, a saturated aqueous sodium hydrogen carbonate solution and a saturated NaCl solution, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to obtain 574 mg (Yield: 90%) of the desired compound.
