To an ice-cooled solution of ethyl (2E)-3-{5-chloro-6-[(3R)-3-pyrrolidinylamino]-3-pyridyl}acrylate dihydrochloride (330 mg) and Et3N (0.437 ml) in dichloromethane (8 ml) was added benzoyl chloride (132 mg), the mixture was stirred at 23° C. for 1 hour. The mixed solution was poured into a mixture of water (20 ml) and DCM (15 ml). The organic layer was separated, washed with brine, dried over sodium sulfate and evaporated under reduced pressure. The resulting residue was purified by column chromatography on silica gel (12 g) using a mixed solvent of dichloromethane and MeOH (100:1 to 40:1). The fractions containing the objective compound were collected and evaporated under reduced pressure. ethyl (2E)-3-(6-{[(3R)-1-benzoyl-3-pyrrolidinyl]amino}-5-chloro-3-pyridyl)acrylate (245 mg) was obtained as colorless syrup.
