4-Methylmorpholine → [(S)-1-(7-Fluoro-1-phenyl-1H-benzoimidazol-2-yl)ethyl]carbamic acid tertbutyl ester

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Reaction Steps

A mixture of (S)-2-tertbutoxycarbonylaminopropionic acid (480 mg, 2.53 mmol), 3-fluoro-N2-phenylbenzene-1,2-diamine (466 mg, 2.30 mmol), HOAt (345 mg, 2.53 mmol), 4-methylmorpholine (560 μL, 5.07 mmol) and N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (486 mg, 2.53 mmol) in DCM (15 mL) was stirred at RT for 2 h. The reaction mixture was then partitioned between additional DCM and an aqueous solution of NaHCO3. The organic layer was dried and concentrated in vacuo and the resulting residue (1.0 g) was dissolved in AcOH (20 mL) and stirred for 18 h at 70° C. After cooling to RT, volatiles were evaporated under reduced pressure and the residue was partitioned between EtOAc and a saturated solution of NaHCO3. The organic layer was washed with water, followed by brine, then dried (Na2SO4) and concentrated in vacuo. The resulting residue was purified by column chromatography (Si—PCC, gradient 0-30% EtOAc in DCM) affording [(S)-1-(7-Fluoro-1-phenyl-1H-benzoimidazol-2-yl)ethyl]carbamic acid tertbutyl ester as a yellow/orange oil (631 mg, 77%). LCMS: RT 3.64 min [M+H]+ 356.0.

Provenance & Evidence