67-56-1

3054-01-1

16741-80-3

The general procedure for the synthesis of S-benzyl-L-cysteine methyl ester hydrochloride from methanol and S-benzyl-L-cysteine is as follows: Example 1: Synthesis of OFN(L-cyanocyclopropyl)-3-phenylmethylsulfonyl-2(R)-(2,2,2-trifluoro-1(RS)-thiophen-2-yl-ethylamino)propionamide Step 1: 2(R)-amino-3-phenylmethane-based sulfuric acid (commercially available) (4.01 g, 19.0 mmol) was dissolved in methanol (100 mL), cooled to 0°C and stirred. HCl gas was passed into this solution for 15 min, after which the reaction mixture was sealed and stirring was continued overnight at room temperature. After completion of the reaction, the solvent was evaporated under vacuum to give propyl methyl 2(R)-amino-3-phenylmethane sulfate hydrochloride (4.98 g) in quantitative yield.