[C:1]([O:4][CH:5]([CH2:9][CH2:10][S:11][CH3:12])[C:6]([OH:8])=O)(=[O:3])[CH3:2].S(Cl)(Cl)=O.C(N(CC)CC)C.[CH2:24]([NH2:36])[CH2:25][CH2:26][CH2:27][CH2:28][CH2:29][CH2:30][CH2:31][CH2:32][CH2:33][CH2:34][CH3:35]>ClCCl>[C:1]([O:4][CH:5]([CH2:9][CH2:10][S:11][CH3:12])[C:6]([NH:36][CH2:24][CH2:25][CH2:26][CH2:27][CH2:28][CH2:29][CH2:30][CH2:31][CH2:32][CH2:33][CH2:34][CH3:35])=[O:8])(=[O:3])[CH3:2]To a solution of 2-acetoxy-4-(methylthio)butanoic acid (17.1 g, 89 mmol) in dichloromethane (350 mL) at 0° C. was added thionyl chloride (32.4 mL, 445 mmol) dropwise over 1 hr. The reaction was stirred at 0° C. for 1.5 hrs then the cooling bath was removed and the reaction was warmed to room temperature with stirring for 3 hrs. The solvent was evaporated and the resulting oil was dried under high vacuum for 1 hr to give an orange oil. A solution of the resulting oil in dichloromethane (˜30 mL) was added to a solution of triethylamine (24.8 mL, 178 mmol) and dodecylamine (20.5 mL, 89 mmol) in dichloromethane (150 mL) at 0° C. and the reaction was allowed to warm to room temperature with stirring overnight. The reaction was evaporated, re-dissolved in EtOAc (300 mL) and washed with 1N HCl (3×150 mL), saturated sodium bicarbonate (3×150 mL), and brine (1×150 mL). The organic layer was dried over magnesium sulfate, filtered and evaporated to give an oil. The oil was purified by silica gel chromatography with 0-40% EtOAc/heptane to give a yellow oil. (22.5 g, 70%). m/z 360 (MH+).
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