556-27-4

21593-77-1

556-27-4

General procedure for the synthesis of (R)-3-((S)-allyl sulfinyl)-2-aminopropionic acid from (R)-3-(allyl sulfinyl)-2-aminopropionic acid: Pure 2-PeCS (0.2 mol) obtained in step (2) was dissolved in 250 mL of distilled water, and 0.28 mol of a 30% hydrogen peroxide solution was added slowly with magnetic stirring, and the stirring was continued for 12 hours. After completion of the reaction, insoluble impurities in the solution were removed by filtration, followed by the addition of 2 L of anhydrous ethanol, and the mixture was allowed to stand at 4 °C for 6 h to induce the formation of 2-PeCSO crystals. The crystals were collected by filtration and dried at 40 °C to obtain 33.6 g of thioallyl cysteine sulfoxide (2-PeCSO). The 2-PeCSO crystals made in step (3) were dissolved in 150 mL of distilled water, heated to 50 °C and a pre-diluted acetone solution (consisting of 96 mL of distilled water with 492 mL of acetone) was slowly added at this temperature and subsequently cooled to room temperature. The mixture was allowed to stand at 4°C for 12 hours. Next, another diluted acetone solution (a mixture of 8.2 mL of distilled water with 112 mL of acetone) was added at 50°C, heat-filtered and cooled to room temperature. The solution was again allowed to stand at 4°C for 12 hours to promote crystallization. Finally, the solution was purified by thermal filtration, the crystals were collected and dried in 15 mL of distilled water to give about 3.3 g of (+)2-PeCSO in pure form.