Methanol → Leucine methyl ester hydrochloride

Participants

Reaction Steps

To a suspension of (L)-leucine, (315 g, 2.4 mol) in MeOH (3.2 L) at −15° C. was added SOCl2 (315 mL, 4.32 mol, 1.8 equiv.) dropwise at such a rate that the temp. of the reaction did not exceed 5° C. After the addition was complete, the reaction mixture was allowed to warm to room temp. and was stirred overnight. The resulting mixture was concentrated under reduced pressure and Et2O (3 L) was slowly added to the residue to produce a precipitate. The mixture was cooled with an ice bath, then treated with additional MeOH (3 L) relatively rapidly. After 1 h at 0° C., the crystals were collected and dried to give (L)-leucine methyl ester HCl salt as a white crystalline solid (394 g, 86%): mp 147-149° C.; 1H-NMR (CD3OD) δ0.78-0.98 (m, 6 h), 1.58-1.72 (m, 3H), 3.76 (g, 3H), 3.92 (t, J=7.3 Hz, 1H).

Provenance & Evidence