To a stirring solution of 1.71 g (14.75 mmol) of thiotetronic acid in 10 mL of dimethylformamide is added 2.22 mL (17.2 mmol) of triethylamine and 592 mg (4.85 mmol) of 4-diemthylaminopyridine at 0° C. Next, 3.38 g (17.6 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 5.0 g (17.7 mmol) of oleic acid are added and the reaction mixture is stirred overnight at room temperature. The reaction is acidified with 1.0N HCl and extracted three times with diethyl ether. The combined organic layers are washed with brine, dried over Na2SO4, filtered, and concentrated in vacuo. The residue is subjected to HPLC chromatography (2 inch Dynamax silica gel column, 25 mL/min) eluting with 100% ethyl acetate to give 1.85 g (33%) of 4-hydroxy-3-[(Z)-1-oxo-9-octadecenyl]-2(5H)-thiophenone as an oil.
