4-Methylmorpholine → 3-Benzyloxycarbonylamino-succinamic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of (S)-2-benzyloxycarbonylamino-succinic acid-4-tert-butyl ester (20.0 g, 61.9 mmol) in CH2Cl2 (100 mL) at −10° C. in a salt/ice/water bath was added N-methylmorpholine (8.20 mL, 74.20 mmol). This was followed by dropwise addition of isobutyl chlorofomate (9.63 mL, 74.20 mmol), over 20 min. After 30 min of stirring at −10° C., ammonium hydroxide solution (28% w/w ammonia, 100 mL) was added portionwise over 5 min. The reaction mixture was stirred for another 8 h then followed by removal of the CH2Cl2 in vacuo. The remaining solution was extracted with EtOAc. The combined extracts were washed with 100 mL of each of the following: 5% citric acid, saturated NaHCO3, and brine. Drying and removal of solvents under vacuum gave crude oil which crystallized from Et2O/hexanes mixture. 3-benzyloxycarbonylamino-succinamic acid tert-butyl ester was obtained in 95% yield (19.0 g). MS (APCI) m/z 323.2 (M+1).

Provenance & Evidence