To a solution of 6,7-bis(palmitoyloxy)-4-thiaheptanoic acid as obtained in Reference Example 4 (400 mg) and glycylglycylglycine t-butyl ester hydrochloride (149 mg) in dimethylformamide (6 ml), triethylamine (0.094 ml) and diethyl cyanophosphate (150 mg) were added at 0° C., followed by stirring at room temperature for 1 hour. After addition of water, the reaction mixture was extracted with chloroform. The extract was washed with a 5% aqueous solution of citric acid, a saturated aqueous solution of sodium hydrogen carbonate and saturated saline, and dried over anhydrous sodium sulfate, and the solvent was distilled off. The resulting residue was recrystallized (acetone-hexane) to yield the title compound (110 mg, yield 20%) as a wax-like substance.
