A mixture of 1.64 g of N-(3-amino-4-chlorophenyl)phthalimide, 2.68 g of isopentyl 2-bromopropionate, and 0.60 g of sodium hydrogencarbonate was heated at 150° C. for 5 hours while stirring. While the reaction mixture was hot, ethyl acetate was added thereto, and the reaction mixture was washed successively with water and a saturated sodium chloride aqueous solution, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure, and the residue was purified by silica gel column chromatography (ethyl acetate-hexane=1:8) to give 1.63 g of the title compound (Table 1, Compound No. 5).
