Water → Benzoyl-D-threonine methyl ester

Participants

Reaction Conditions

Reaction Steps

A crude D-threonine methyl ester (39.49 g) was dissolved in 300 mL of methanol and than transferred to the 1 L 3-neck round bottom flask equipped with a thermocouple, magnetic stirrer and cooling ice bath. A solution was chilled to 12° C., and a total of 64.1 g (0.63 mol, 3 eq.) was added to the flask and then cooled to −10° C. A total of 30.9 g (0.21 mol) of benzoyl chloride was added to the solution and resulting mixture stirred at 0° C. for 1 hour. After this period of time the solvent was removed on rotovap to yield a viscous semi-solid. A total of 300 mL of cold water was added to the residue and organic material was extracted with ethyl acetate (2×300 mL). The organic phase was separated, washed with brine (200 mL) and dried over sodium sulfate. The solvent was removed on rotovap to yield 52.02 g (104%) of a clear yellow oil with Rf=0.39 in EtOAc/hexane=6:4). Obtained oil was crystallized from 200 mL of ether to give a white solid, which was filtered off, washed with hexane (2×100 mL) and dried under suction. An additional drying in a vacuum desiccator yielded 42.35 g (84.7% yield in 2 steps).

Provenance & Evidence