Methyl chloroformate → (2S,3R)-3-methoxy-2-(methoxycarbonylamino)butanoic acid

Participants

Reaction Steps

A solution of O-methyl-L-threonine (1.01 g, 7.59 mmol) in saturated bicarbonate solution (93 mL) was treated dropwise with methyl chloroformate (900 μL, 1.10 g, 11.61 mmol), followed by stirring at RT for 24 h. The mixture was extracted methyl t-butyl ether and cooled to 0° C. The mixture was adjusted to pH 1-2 by addition of concentrated hydrochloric acid solution. The mixture was extracted with ethyl acetate (3×) and the combined extracts were extracted with saturated sodium chloride solution and dried (Na2SO4). The solution was concentrated in vacuo to afford the title compound (1.31 g, 90%) as a white solid. 1H NMR (400 MHz, CDCl3) δ 5.44 (d, J=8.7 Hz, 1H), 4.39 (dd, J=8.7, 2.3 Hz, 1H), 4.00 (dd, J=6.2, 2.4 Hz, 1H), 3.71 (s, 3H), 3.36 (s, 3H), 1.21 (t, J=7.2 Hz, 3H). MS (+ESI) m/z (rel abundance) 192 (60, M+H), 209 (100, M+NH4).

Provenance & Evidence