Triethylamine (0.210 mL), acetyl chloride (0.0807 mL) and 4-dimethylaminopyridine (13.5 mg) were added to 1-[1-(6-methoxy-3-pyridyl)-5-(2-pyridyl)pyrazole-3-carbonyl]hexahydropyridazine (0.275 g) obtained in Example 162 in methylene chloride (6.0 mL) at room temperature, followed by stirring for 20 minutes. The mixture was partitioned between water and chloroform. The organic layer was washed with saturated brine, and then dried over sodium sulfate anhydrate. The mixture was subjected to filtration, and the solvent was removed under reduced pressure. The residue was purified through silica gel column chromatography (chloroform-methanol), to thereby give the title compound as an amorphous product (0.149 g, 59%).
