2,3-dihydro-1,3-benzothiazole synthesized from 2-aminobenzenethiol (347 mg) and 37% formalin (0.23 mL) in the same manner as in Example 1 was dissolved in dichloromethane (3 mL), and diisopropylethylamine (0.63 mL) and 4-benzyloxy-3-chloro-5-methoxybenzoyl chloride (578 mg) were added to the solution, and then the mixture was stirred at room temperature for 1.5 hours. The solvent was distilled off under reduced pressure and water was added, and then the mixture was extracted with ethyl acetate. The organic layer was washed with 1N hydrochloric acid, 1N sodium hydroxide and saturated brine, and then dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure and the obtained residue was purified by silica gel column chromatography (n-hexane:ethyl acetate=6:1) to obtain the title compound (498 mg) as a pale yellow oily substance.
