4-Methylmorpholine → [1-(2-Phenylaminophenylcarbamoyl)ethyl]carbamic acid tertbutyl ester

Participants

Reaction Steps

N-Phenylbenzene-1,2-diamine (1.84 g, 0.01 mol), racemic (R/S)-2-tertbutoxycarbonylaminopropionic acid (1.89 g, 0.01 mol), N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (1.92 g), 4-methylmorpholine (1.0 g, 0.01 mol), HOBt (1.53 g, 0.01 mol) were suspended in THF (10 mL) under a nitrogen atmosphere. The resulting mixture was stirred for 12 h at RT. After this period of time, additional amounts of N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (500 mg×3) and of (R/S)-2-tertbutoxycarbonylaminopropionic acid (500 mg) were added and the mixture was stirred for further 4 h. The reaction mixture was then partitioned between water and EtOAc. The organic layer was separated, dried (MgSO4) and concentrated in vacuo and the resulting residue was purified by column chromatography (Si—PCC ISCO 24 g column, gradient 0-20% EtOAc in cyclohexane). The product containing fractions were combined and concentrated in vacuo affording [1-(2-Phenylaminophenylcarbamoyl)ethyl]carbamic acid tertbutyl ester as a white crystalline solid (3.07 g, 86%). LCMS: RT 3.61 min [M+H-tBu]+ 300.1.

Provenance & Evidence