Ethanol → ethyl (2R)-2-amino-6-{[(benzyloxy)carbonyl]amino}hexanoate

Participants

Reaction Conditions

Reaction Steps

3.9 cm3 of thionyl chloride are added to a stirred suspension of 7.9 g of (2R)-2-amino-6-{[(benzyloxy)carbonyl]amino}hexanoic acid (Ns-CBZ-D-lysine) in 120 cm3 of anhydrous ethanol cooled to a temperature in the region of −25° C. The mixture is stirred for 3 hours at this temperature and is then allowed to warm to about 20° C. After leaving for 3 days, the reaction mass is concentrated under reduced pressure (5 kPa) at a temperature in the region of 0° C. The residue obtained is taken up in 200 cm3 of ethyl acetate and the resulting solution is washed with aqueous sodium carbonate solution and then with aqueous sodium chloride solution. The organic solution is dried over magnesium sulfate, filtered and concentrated under reduced pressure (5 kPa) at a temperature in the region of 40° C. 7.4 g of ethyl (2R)-2-amino-6-{[(benzyloxy)-=carbonyl]amino}hexanoate are obtained in the form of a pale yellow oil. (αD20=−11.7±0.6 at a concentration of 0.5% in methanol).

Provenance & Evidence