To a solution of 2-[4-(benzyloxycarbonyl)piperazin-1-yl]-4-[(1S,4R)-(4-hydroxycyclopent-2-en-1-yl)oxy]quinazoline [cf. Example 33(3)] (750 mg) and methyl iodide (445 mg) in dimethylformamide (6 ml) is added 60% sodium hydride (oil) (94 mg) with stirring at room temperature, and the mixture is stirred at room temperature for 3 hours. The reaction mixture is diluted with ethyl acetate, and washed with water 5 times. The ethyl acetate solution is dried over anhydrous magnesium sulfate and evaporated to dryness under reduced pressure. The resulting residue is purified by medium pressure liquid column chromatography [eluent, chloroform, (chloroform:methanol=200:1, v/v)] to give 2-[4-(benzyloxycarbonyl)piperazin-1-yl]-4-[(1S,4R)-(4-methoxycyclopent-2-en-1-yl)oxy]quinazoline (710 mg) as oil.
