Synthesis
General procedure for the synthesis of (S)-2-amino-3-(4-sulfophenyl)propionic acid from L-phenylalanine: a mixture of 2.8 g of chlorosulfonic acid (24 mmol) and 1.95 g of L-phenylalanine (12 mmol) was added to a 100 mL round-bottomed flask, and the reaction was cooled in an ice-water bath for 12 hours. Upon completion of the reaction, ice water was slowly added to the reaction solution until a deep pink precipitate appeared, followed by rapid filtration through a Büchner funnel. The pink colored filtrate obtained was dissolved in distilled water and heated in an oil bath at 60°C. After the crystals were completely dissolved, 0.5 g of activated carbon was added for decolorization and the filtrate was collected after filtration. Isopropanol was added to the filtrate for crystallization. After crystallization, the crystals were washed with water, dried and filtered, and finally the solvent was removed by vacuum evaporation. Finally, 2.6 g of white solid product was obtained with 87% yield (Figure 1C).
References
[1] Letters in Drug Design and Discovery, 2015, vol. 12, # 6, p. 466 - 470
[2] Helvetica Chimica Acta, 1983, vol. 66, # 5, p. 1355 - 1365
[3] Bioorganic and Medicinal Chemistry Letters, 2010, vol. 20, # 8, p. 2680 - 2683
