L-Alanine → N-Tosyl-L-alanine

Participants

Reaction Conditions

Reaction Steps

L-alanine (100 g; 1.11 moles) was dissolved in 2.25 L of 1N sodium hydroxide (aq), cooled to 5° C. and stirred while a solution of p-toluenesulfonyl chloride (218 g; 1.11 moles) dissolved in 450 mL of toluene was added slowly. The mixture was stirred at ambient temperature for 20 hr. The layers were separated and the chilled aqueous layer acidified to pH 1 with concentrated hydrochloric acid. The white solid title compound was collected by filtration, washed with water and dried. Yield 178.5 g (66%) mp 134°-5° C. IR (CHCl3) cm-1 1726, 1340, 1165, 1095; 1H NMR (DMSO-D6) δ 1.20 (d, J=7, 3H), 2.40 (s, 3H), 3.85 (p, J=8, 1H), 6.4 (br s, 1H) (CO2H), b 7.41 (d, JAB =8, 2H) and 7.75 (d, JAB =8, 2H) [center of pattern: 7.58; ΔVAB =20.49 Hz], 8.03 (br d, J=8, 1H) (NH).

Provenance & Evidence