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

A solution of allo-O-methyl-L-threonine (519 mg, 3.90 mmol) in saturated sodium bicarbonate solution (47.6 mL) was treated dropwise with methyl chloroformate (453 μL, 553 mg, 5.85 mmol) followed by stirring at RT for 18 h. The mixture was extracted with ether and the aqueous phase was cooled to 0° C. and acidified to pH 2-3 by addition of concentrated hydrochloric acid solution. The mixture was extracted with ethyl acetate (3×). The combined organic layers were extracted with saturated sodium chloride solution and dried (Na2SO4). Concentration in vacuo afforded the title compound (640 mg, 86%) as a colorless oil. 1H NMR (400 MHz, CDCl3) δ 5.48 (d, J=7.8 Hz, 1H), 4.52 (d, J=4.7 Hz, 1H), 3.71 (s, 3H), 3.39 (s, 3H), 1.25 (t, J=7.6 Hz, 3H).

1. extractionThe mixture was extracted with ether
2. temperaturethe aqueous phase was cooled to 0° C.
3. additionacidified to pH 2-3 by addition of concentrated hydrochloric acid solution
4. extractionThe mixture was extracted with ethyl acetate (3×)
5. extractionThe combined organic layers were extracted with saturated sodium chloride solution
6. dry with materialdried (Na2SO4)
7. concentrationConcentration in vacuo

ORD record

ord-5d2f9ff49bfe4c2e8b8ceb47afbe662a

Source dataset

uspto-grants-2015_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09006387B2