350 mg (1.15 mmol) of the 7-amino-3-(2-trifluoromethylphenyl)-2H-isoquinolin-1-one obtained in Example 38 was dissolved in 11.5 ml of methanol, and thereafter, 1.15 ml of acetic acid and 552.5 mg (4.60 mmol) of glycolaldehyde dimer were added thereto. Thereafter, 722 mg (11.5 mmol) of sodium cyanoborohydride was added to the mixture under cooling on ice. The temperature of the mixture was increased to a room temperature, and the mixture was then stirred for 8 hours. Thereafter, a saturated sodium bicarbonate aqueous solution was added to the reaction solution, and the mixture was then extracted with ethyl acetate. The extract was dried over anhydrous sodium sulfate and was then concentrated. The obtained residue was purified by silica gel column chromatography (methylene chloride:methanol=20:1 to 12:1), so as to obtain 61.8 mg (15%) of 7-(2-hydroxyethylamino)-3-(2-trifluoromethylphenyl)-2H-isoquinolin-1-one in the form of a yellow amorphous substance, as well as 369.3 mg (82%) of 7-[bis(2-hydroxyethyl)amino]-3-(2-trifluoromethylphenyl)-2H-isoquinolin-1-one in the form of a yellow foaming substance.
