The oil obtained in Example 140 was dissolved in methanol (5 mL) and tetrahydrofuran (5 mL), and 2 N aqueous sodium hydroxide solution (3 mL) was added. The mixture was stirred at room temperature for 1 hr. The reaction mixture was diluted with water, and neutralized with 1 N aqueous hydrochloric acid solution, and the mixture was extracted with ethyl acetate. The ethyl acetate layer was dried using a Presep Dehydration tube (Manufactured by Wako Pure Chemical Industries, Ltd.), and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (hexane:ethyl acetate=9:1-1:4) to give the title compound (90 mg, yield 18%, 2 steps) as colorless crystals. 1H NMR (CDCl3) δ: 1.37 (9H, s), 2.64 (2H, t, J=7.6 Hz), 2.91 (2H, t, J=7.6 Hz), 4.97 (2H, s), 5.32 (2H, s), 6.20 (1H, s), 6.67 (2H, s), 7.01 (2H, d, J=8.3 Hz), 7.09 (1H, t, J=8.8 Hz), 7.25-7.40 (7H, m).
