Synthesis
The general procedure for the synthesis of S-benzyl-L-cysteine from L-cysteine hydrochloride and benzyl bromide was as follows: to a rapidly stirred mixture of 2N sodium hydroxide solution (15 mL) and ethanol (35 mL), L-cysteine hydrochloride (1.3 g, 8.2 mmol) and benzyl bromide (0.98 mL, 8.2 mmol) were added sequentially. After the reaction was carried out for 1 h, concentrated hydrochloric acid was slowly added to neutralize the reaction mixture to pH 6-7. Subsequently, the precipitate was collected by filtration and washed sequentially with water, ethanol, and ether to yield S-benzyl-L-cysteine (7) as a white powdery product (1.87 g, 92% yield) with a melting point of 210-212 °C (literature value: 215-216 °C).
References
[1] European Journal of Medicinal Chemistry, 2012, vol. 55, p. 176 - 187,12
[2] Journal of Pharmaceutical Sciences, 1984, vol. 73, # 4, p. 559 - 561
[3] Organic Preparations and Procedures International, 1991, vol. 23, # 1, p. 93 - 102