4-Methylmorpholine → [(S)-1-(4-fluoro-2-phenylaminophenylcarbamoyl)-2-methoxyethyl]carbamic acid tert-butyl ester

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Reaction Steps

A mixture of 4-fluoro-N2-phenylbenzene-1,2-diamine (450 mg, 2.2 mmol), (S)-2-tertbutoxycarbonylamino-3-methoxypropionic acid (525 mg, 2.4 mmol), HOAt (330 mg, 2.4 mmol), 4-methylmorpholine (0.53 mL, 4.8 mmol) and N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (460 mg, 2.4 mmol) in DCM (10 mL) was stirred at RT for 18 h. The reaction mixture was partitioned between DCM and a saturated aqueous solution of NaHCO3. The organic phase was washed with brine, dried (MgSO4) concentrated in vacuo and the resulting residue was purified by column chromatography (Si—PCC, gradient 0-30% EtOAc in cyclohexane) to afford [(S)-1-(4-fluoro-2-phenylaminophenylcarbamoyl)-2-methoxyethyl]carbamic acid tert-butyl ester (0.655 g, 74%). A solution of the compound thus obtained (0.655 g) in AcOH (10 mL) was heated at 70° C. for 56 h. After cooling to RT, the volatiles were removed in vacuo and the resulting residue partitioned between DCM and a saturated aqueous solution of NaHCO3. The organic layer was washed with brine, dried (MgSO4) and concentrated in vacuo. The resulting residue was purified by column chromatography (Si—PCC, gradient 0-30% EtOAc in cyclohexane) to afford the title compound (227 mg, 28%). LCMS (Method J): RT 3.59 and 3.70 min [M+H]+ 386.2

Provenance & Evidence