4-Methoxybenzenesulfonyl chloride → N-[4-methoxybenzenesulfonyl]-(D)-valine

Participants

Reaction Steps

To an ice-cooled solution of D-valine (50.5 g, 0.43 mol) and triethylamine (145 mL, 1.034 mol) in a 1:1 mixture of tetrahydrofuran and water (350 mL) was added 4-methoxybenzenesulfonyl chloride (88.2 g, 0.43 mmol). The reaction mixture was stirred and allowed to warm to room temperature overnight. The volatile organics were removed and the aqueous phase was extracted with diethyl ether. The aqueous phase was acidified to pH 3 with 10% hydrochloric acid and the product was extracted into ethyl acetate. The ethyl acetate layer was washed with brine, dried over magnesium sulfate, and then concentrated to give 2(R)-(4-methoxy-benzenesulfonylamino)-3-methylbutyric acid as a white solid (90.45 g).

Provenance & Evidence