4-Methylmorpholine → [(R)-1-(2-methyl-6-phenylaminophenylcarbamoyl)ethyl]carbamic acid tertbutyl ester

Beteiligte Stoffe

Reaktionsschritte

To a solution of 3-methyl-N1-phenylbenzene-1,2-diamine (381 mg, 1.92 mmol) in anhydrous DCM (10 mL) were added (R)-2-tertbutoxycarbonylaminopropionic acid (399 mg, 2.11 mmol), HOBt (285 mg, 2.11 mmol), 4-methylmorpholine (464 μL, 4.22 mmol) and N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (404 mg, 2.11 mmol) and the mixture was stirred at RT for 2 h. After this period of time, additional amounts of (R)-2-tertbutoxycarbonylaminopropionic acid (145 mg, 0.77 mmol) and of N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (148 mg, 0.77 mmol) were added. Stirring was continued for 20 h and then additional amounts (R)-2-tertbutoxycarbonylaminopropionic acid (545 mg, 2.88 mmol), HOBt (285 mg, 2.11 mmol), 4-methylmorpholine (464 μL, 4.22 mmol) and N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (553 mg, 2.88 mmol) were added. Stirring was continued for 24 h and then the crude mixture was purified by column chromatography (Si—PCC, gradient 0-40% EtOAc in cyclohexane) affording [(R)-1-(2-methyl-6-phenylaminophenylcarbamoyl)ethyl]carbamic acid tertbutyl ester as an orange oil (456 mg, 64%). LCMS: RT 3.69 min [M+H]+ 370.2

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