To 0.7 mL of an N,N-dimethylformamide solution containing 74 mg of 60% sodium hydride, 0.14 g of imidazole was added at room temperature, and the mixture was stirred for 10 minutes. Thereto were added 0.20 g of 7-bromo-1-(1,3-dioxolan-2-ylmethyl)-4-methylquinolin-2(1H)-one and 17 mg of copper(II) oxide, and the mixture was heated to 140 to 145° C. and stirred for 40 minutes. Thereto was further added 2 mL of N,N-dimethylformamide, and the mixture was further stirred for 1 hour. The reaction mixture was cooled to room temperature, then chloroform and water were added thereto, and the insoluble material filtered off. The organic layer was separated, and the aqueous layer was extracted with chloroform. The organic layer and the extract were combined, the resultant solution was dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. The residue thus obtained was purified by silica gel column chromatography [eluent; chloroform:methanol=10:1] to obtain 77 mg of a brown oily substance, 1-(1,3-dioxolan-2-ylmethyl)-7-(1H-imidazol-1-yl)-4-methylquinolin-2(1H)-one.
