Triethylamine → (S)-Methanesulphonic acid 2-Boc-aminopropyl ester

Participants

Reaction Steps

Methanesulfonyl chloride (13.2 mL, 170 mmol) was added to a 0° C. solution of tert-butyl [(2S)-1-hydroxypropan-2-yl]carbamate (28.4 g, 162 mmol) and triethylamine (27 mL, 190 mmol) in dichloromethane (350 mL), and the reaction mixture was allowed to stir for 30 minutes. After aqueous ammonium chloride solution was added to the reaction mixture, the aqueous layer was extracted with dichloromethane, and the combined organic layers were dried over magnesium sulfate, filtered, and concentrated in vacuo. The resulting sticky white solid was slurried with diethyl ether (100 mL), stirred for 10 minutes, and filtered to afford the product as a white solid. Yield: 28.8 g, 114 mmol, 70%. The filtrate was concentrated under reduced pressure and recrystallized from diethyl ether (the hot mixture was filtered through Celite before crystallization) to provide additional product as a white solid. Yield: 11.66 g, 45.63 mmol, combined yield 98%. 1H NMR (400 MHz, CDCl3) δ 1.24 (d, J=7.0 Hz, 3H), 1.45 (s, 9H), 3.04 (s, 3H), 3.91-4.04 (br m, 1H), 4.16 (dd, half of ABX pattern, J=10.1, 4.2 Hz, 1H), 4.19-4.28 (br m, 1H), 4.62 (br s, 1H).

Provenance & Evidence