(-)-Asparagine → N-Phenysulfonyl-L-asparagine

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of L-asparagine (Aldrich) (10 g, 76 mmol), NaOH (3.4 g, 85 mmol), H2O(50 mL), and dioxane (50 mL) at 0°C. was added PhSO2Cl(10.6 mL, 84 mmol). After 1 min. NaOH (3.4 g) in H2O(50 mL) was added and the reaction mixture stirred for 30 min. The reaction mixture was then concentrated to remove the dioxane, then washed with EtOAc. The aqueous phase was then cooled to 0° C. and acidified to pH 2-3 with conc. HCl to effect product precipitation. The resulting solid was collected by filtration, washed with H2O(20 mL) and dried at 50° C. under vacuum to give 7-8 as a white solid. Rf 0.40 (silica, 10:1:1 ethanol/H2O/NH4OH). 1H NMR (300 MHz, D2O)δ7.59 (m, 2H), 7.26 (m, 3H), 3.92 (m, 1H), 3.02 (m, 1H), 2.35 (m, 1H).

Provenance & Evidence