Phosphate → Acetic acid, [(1-ethoxyethyl)thio]-

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Reaction Steps

S-(1-ethoxyethyl)mercaptoacetic acid 16 was prepared according to the following procedure: A solution of mercaptoacetic acid (17.4 mL, 250 mmol) in 125 mL of dichloromethane containing p-toluenesulfonic acid monohydrate (0.24 g, 1.26 mmol) was cooled to -18° to -25° C. with stirring. Ethyl vinyl ether (23.9 mL, 250 mmol) in 125 mL of dichloromethane was added dropwise to the cold solution over a period of 90 minutes. The stirring was continued for an additional 30 minutes, with the temperature maintained in the -18° to -25° C. range. Then 200 mL of pH 7 phosphate buffer was added, and the reaction mixture was allowed to warm with stirring for 10 to 15 minutes. The mixture was then poured into a flask containing 900 mL of ethyl acetate and 200 mL of water. Layers were separated, and the aqueous portion extracted twice with ethyl acetate. The organic layers were combined, washed with brine, and dried (MgSO4). Removal of the solvent left 31.4 g of S-(1-ethoxyethyl)mercaptoacetic acid 16 as a colorless oil (77% yield): 1H NMR (CDCl3) 1.15(t,J=7.0 Hz,3H), 1.52(d,J=6.4 Hz,3H), 3.36(s,2H), 3.60(m,2H), 4.84(q,J=6.4 Hz, 1H), 11.65(s, 1H). The material was used without further purification.

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