Methanol → Methyl L-phenylalaninate hydrochloride

Participants

Reaction Steps

Thionyl chloride (3.10 mL, 42.38 mmol, 1.4 eq) was added dropwise to a suspension of L-phenylalanine (5.0 g, 30.27 mmol, 1.0 eq) in dry MeOH (30 mL) at 0° C. The cold bath was removed and the solution was stirred at room temperature for 24 h, then concentrated under vacuum. The residue was triturated with cold Et2O, filtered and wash with cold Et2O and the filtrate evaporated in vacuo to give the L-phenylalanine methyl ester hydrochloride as a white crystalline solid in quantitative yield; IR (KBr) ν 1740 (CO), 3305 (NH) cm−1; 1H NMR (300 MHz, CDCl3) δH 1.46 (2H, s, —NH2), 2.75 (1H, dd, J=6.8 and 14.1 Hz, —CHαPh), 3.00 (1H, dd, J=6.7 and 14.2 Hz, —CHβPh), 3.72 (3H, s, OMe), 4.65 (1H, t, J=6.8 Hz, —CH—) and 7.10-7.30 (5H, m, Ar—H), which was sufficiently pure and used directly in the next step.

Provenance & Evidence