Methanesulfonyl chloride → (2S,4R)-N-methanesulfonyl-4-hydroxyproline ethyl ester

Participants

Reaction Steps

In 200 ml of pyridine was placed 19.56 g (0.1 mol) of (2S,4R)-4-hydroxyproline ethyl ester hydrochloride, and 12.03 g (0.105 mol) of methanesulfonyl chloride was slowly added dropwise to the mixture under agitation and ice-cooling. After stirring the mixture under ice-cooling for 6 hours, the mixture was further stirred overnight at room temperature. After distilling off the pyridine under reduced pressure, 10% hydrochloric acid was added to the reaction mixture under ice-cooling. The mixture was extracted three times with 200 ml of ethyl acetate in each case and the ethyl acetate extracts were combined, washed with 40 ml of a saturated aqueous solution of sodium chloride and then dried over magnesium sulfate. The extract was concentrated under reduced pressure and dried until dryness whereby a solid substance having a melting point of 111°-113° C. was obtained in a yield of 18.7 g (78.9%) which, after recrystallization from ethyl acetate, showed a melting point of 118°-120° C.

Provenance & Evidence