4-Methylmorpholine → HCID 69652473, compound

Participants

Reaction Conditions

Reaction Steps

74.45 g (0.237 mol) of N-Boc-(2-hydroxyphenyl)-L-cysteine (VIII) and 300 ml of distilled tetrahydrofuran are introduced into a round-bottomed flask kept under an inert atmosphere. The mixture is cooled to −10° C. and then 26 ml (0.236 mol) of N-methylmorpholine are added dropwise. After stirring for 15 minutes at −10° C., 22.7 ml (0.237 mol) of ethyl chloroformate are introduced dropwise. The mixture is stirred at −10° C. for 30 minutes and then the precipitate formed is filtered off under cold conditions. The filtrate is recovered directly in a round-bottomed flask and cooled to −10° C. 13.45 g (0.35 mol) of sodium borohydride in solution in 50 ml of water are then introduced in such a way that the temperature of the mixture does not exceed −10° C. At the end of the addition, the mixture is reheated to ambient temperature and stirred for 12 hours. The mixture is concentrated under reduced pressure, acidified using 250 ml of an aqueous potassium hydrogensulfate solution (2N) and extracted with dichloromethane. The combined organic phases are washed with brine, dried over sodium sulfate, filtered and concentrated under reduced pressure. 61.41 g (0.205 mol) of the title compound (IXa-1) are obtained in the form of a yellow oil, which is used without additional purification in the following stage.

Provenance & Evidence