2,3-dihydro-1,3-benzothiazole synthesized from 2-aminobenzenethiol (214 mg) and 37% formalin (0.14 mL) in the same manner as in Example 1 was dissolved in chloroform (4 mL), and triethylamine (0.47 mL) and 3-dimethylcarbamoyl-4-methoxy-5-trifluoromethylbenzoyl chloride were added to the solution, and then the mixture was stirred at room temperature for 1 hour. 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 used for the synthesis of (g).
