15 mg of the compound obtained in Production Example 5 was added to N,N-dimethylformamide (2 mL) solution of 19.7 mg of the compound obtained in Production Example 48, and stirred overnight at 90° C. Water was added to the reaction liquid, and extracted with ethyl acetate. The ethyl acetate layer was dried with anhydrous sodium sulfate, the solvent was evaporated off under reduced pressure, and the residue was separated and purified through preparative thin-layer chromatography (chloroform/methanol 4/1) to obtain 1.2 mg of the entitled compound and 16.6 mg of 7-methylene-5,6,7,9-tetrahydro-8H-pyrido[2,3-b]azepin-8-one. 16.6 mg of the obtained 7-methylene-5,6,7,9-tetrahydro-8H-pyrido[2,3-b]azepin-8-one was dissolved in 2 mL of N,N-dimethylformamide, and 20 mg of 4-o-tolylpiperidine monohydrochloride was added thereto and stirred at 90° C. for 0.5 hours. The reaction solution was concentrated under reduced pressure, and the residue was separated and purified through preparative thin-layer chromatography (chloroform/methanol=4/1) to obtain 12.1 mg of the entitled compound.
