4-Methylmorpholine → Boc-Ala-NH2

Participants

Reaction Steps

To a stirred solution of (2S)-2-[(tert-butoxycarbonyl)amino]propanoic acid (1 g, 0.005 mol) in THF at 0° C. was added 4-methylmorpholine (0.588 g, 0.00581 mol) followed by dropwise addition of isobutyl chloroformate (0.794 g, 0.00581 mol) over 2 min. The reaction was stirred at 0° C. for 30 min. after which a solution of 30 wt. % ammonium hydroxide (12.0 mL, 0.0925 mol) was quickly poured into the reaction. The reaction was warmed to room temperature and stirred for 5 h. The reaction mixture was concentrated. Water was added and the mixture extracted with ethyl acetate. The combined organic layers were washed with brine, dried over MgSO4, filtered and concentrated to afford the crude product which was directly used in the next step reaction without further purification (800 mg, 80%). 1H-NMR (300 MHz, DMSO-d6): 12.40 (s, 1H), 7.10 (d, J=7.0 Hz, 1H), 3.88 (m, 1H), 1.35 (s, 9H), 1.20 (d, J=7.3 Hz, 3H).

Provenance & Evidence