关键词: (S)-3-苯甲酰巯基-2-甲基丙酸, 硫代乙酸, 甲基丙烯酸, 合成, 拆分

Abstract: 3-benzoylthio-2-methylpropionic acid racemate was synthesized by condensation and hydrolysis-esterification reaction of thioacetic acid with methacrylic acid，then (S)-3-benzoylthio- 2-methylpropionic acid was obtained by chemical resolution. The influencing factors in each step were taken into account. The results showed that 3-acetyl-mercapto-2-methyl-propionic acid（condensate A）was obtained with the yield of 95.6% when the molar ratio of thioacetic acid to methacrylic acid was 1.4∶1，reaction time was 2h and reaction temperature was 93 ℃. Condensate A was added into 11.8% sodium hydroxide aqueous solution to make it hydrolysis with kettle temperature below 20 ℃，then sodium salt was put into the kettle，and the same mole benzoyl chloride was dropped as condensate A into the kettle under low temperature. Two hours later，the product was obtained by acidifying the reaction mixture with hydrochloric acid，the yield of product in hydrolysis-esterification reaction was 96.7%. D-(+)-N-benzyl-α-phenylethylamine was used as the resolving agent to split the product，the yield in this step was 36%. Taking all the procedures above into consideration，the yield of final product was 33.3%. The product was characterized with MS，1H NMR and FT-IR analysis，and proved to be with high crystallinity by X ray diffraction.

Key words: (S)-3-benzoylthio-2-methylpropionic acid, thioacetic acid, methacrylic acid, synthesis, resolution