To a solution of 23 mg of 5-[(E)-4,7-dihydroxy-2-heptenylidene]-4-hydroxy-2-methylthio-4-(4-phenoxybutyl)-2-cyclopentenone obtained in Example 91 dissolved in 2 ml of dichloromethane was added 200 μl of triethylamine. Under ice-cooling and stirring. 20 μl of acetylchloride was added, and the mixture was stirred at 0° C. for 2 hours. Saturated aqueous sodium chloride was added, and the mixture was extracted with ethyl acetate. The extract was dried over anhydrous sodium sulfate, filtrate and concentrated, followed by silica gel column chromatography to give 11 mg (yield 43%) of 5-[(E)-4,7-diacetoxy-2-heptenylidene]-4-hydroxy-2-methylthio-4-(4-phenoxybutyl)-2-cyclopentenone (J) and 4 mg (yield 17%) of 5-[(E)-4,7-diacetoxy-2-heptenylidene]-4-acetoxy-2-methylthio-4-(4-phenoxybutyl-2-cyclopentenone (K).
