To a solution of (1S,4R)-4-acetoxycyclopent-2-en-1-ol [manufactured by Fluka Co., cf. Tetrahedron, 46, 3155 (1990)] (2.00 g) and 2,4-dichloroquinazoline (2.80 g) in tetrahydrofuran (52 ml) is added potassium t-butoxide (1.90 g) with stirring under ice-cooling, and the mixture is stirred under ice-cooling for 70 minutes. The reaction mixture is diluted with ethyl acetate, and washed with water. The ethyl acetate solution is dried over anhydrous magnesium sulfate and evaporated to dryness under reduced pressure. The resulting residue is briefly purified with medium pressure column chromatography (eluent, chloroform) to give an oily substance. The oily substance is dissolved in dioxane (16 ml), and the solution is added dropwise to a solution of piperazine (3.25 g) in dioxane (19 ml) with stirring at 50° C., and the mixture is stirred at the same temperature for 1.5 hour. The reaction mixture is diluted with ethyl acetate and washed with water. The ethyl acetate solution is dried over anhydrous magnesium sulfate and evaporated to dryness under reduced pressure, and the resulting residue is purified by medium pressure liquid column chromatography (eluent, chloroform:methanol=10:1, v/v) to give 4-[(1S,4R)-(4-acetoxycyclopent-2-en-1-yl)oxy]-2-(1-piperazinyl)quinazoline (2.12 g) as oil.
