4-Methylmorpholine → Boc-(D)-Met-(L)-Ala-OMe

Participants

Reaction Conditions

Reaction Steps

Boc-(D)-methionine (50.0 g) is dissolved in dichloromethane (200 ml) and 1-hydroxybenzo-triazole hydrate (29.7 g) and (L)-alanine methyl ester hydrochloride (31.0 g) is added. The mixture is cooled to 0° C. and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (43.0 g) is added in portions, maintaining the temperature of the mixture at 0-5° C. N-Methylmorpholine (42.2 g) is then added over 30 minutes, maintaining the temperature of the mixture at 0-5° C. The mixture is then stirred at 0° C. for 5 hours. The reaction mixture is washed successively with water (2×100 ml), 10% aqueous citric acid solution (100 ml), saturated aqueous sodium bicarbonate solution (100 ml), water (100 ml) and evaporated to dryness at 40° C. under reduced pressure to give Boc-(D)-Met-(L)-Ala-OMe (67.0 g estimated to contain 0.17 mol) as an oil.

Provenance & Evidence