To a solution of 6,7-dihydroxy-4-thiaheptanoic acid p-methoxybenzyl ester as obtained in Reference Example 2 (1.99 g) in methylene chloride (26 ml), triethylamine (4.6 ml), palmitoyl chloride (6.00 g) and dimethylaminopyridine (5 mg) were added at 0° C., followed by stirring at room temperature for 24 hours. After addition of 5% citric acid, the reaction mixture was extracted with methylene chloride. The extract was washed with a saturated aqueous solution of sodium hydrogen carbonate and saturated saline, and dried over anhydrous sodium sulfate, and the solvent was distilled off. The residue was recrystallized (methanol-hexane) to yield the title compound (2.30 g, yield 45%) as a white powder.
