S-Methyl methanethiosulfonate → Methyldithio-n-methylcysteine

Participants

Reaction Steps

A solution of N-methylcysteine (7a) (Undhein, K., & Eidem, A., 23 Acta Chem. Scandinavica 3129-3133 (1970)) (1.5 g, 11.1 mmol) in H2O (20 mL) was stirred at room temperature, under an atmosphere of argon, and treated with a solution of methyl methanethiol sulfonate (3.0 mL, 29.2 mmol) in ethanol (10 mL). The reaction mixture was stirred at this temperature for two hours and then diluted with H2O (100 mL) and washed with ether (4×40 mL). The aqueous layer was acidified to pH 2 and passed through an Amberlite IRA 93 (—OH form) column. The column was washed with water and the effluent was collected and evaporated to dryness under reduced pressure to give a white solid (1.2 g, 60%), mp 194-195° C. 1H NMR (D2O, TMS ext. standard): δ2.2(3H,s), 2.5(3H,s), 3.2(2H,d), 3.7(1H,q).

Provenance & Evidence