3-Mercaptopropionic Acid → 3-(4-METHYL-BENZYLSULFANYL)-PROPIONIC ACID

Participants

Reaction Steps

A solution of betamercaptopropionic acid (5.3 g, 50 mMol) in water (95 ml) was diluted with absolute ethanol (80 ml) and triethylamine (15 ml). While this solution was mechanically stirred and cooled with an ice bath, a solution of 4-methylbenzyl bromide (9.4 g) in ethanol (80 ml) was added over a period of 15 minutes. The ice bath was removed and the reaction mixture was stirred at room temperature for 2.5 hours. The mixture was then concentrated in vacuo and the residue was suspended in water (100 ml). As the pH of the suspension was adjusted to 10, the residue dissolved. The resulting solution was extracted three times with di-ethyl ether and the aqueous phase was acidified to pH 1 with concentrated HCl. An oily residue separated. The mixture was then exhaustively extracted with di-ethyl ether, the ether extracted was dried over MgSO4 and concentrated to an oil. The latter solidified on standing and the solid residue was recrystallized from ethyl acetate-liquid petroleum. The yield was 7.9 g (75%), m.p. 75.8° C., NMR (CDCl3) 11.5 (s, 1H), 7.09 (q, 4H), 3.67 (s, 2H), 2.60 (m, 4H), 2.30 (s, 3H).

Provenance & Evidence