Tert-butoxycarbonylalanine → [(S)-1-(8-Fluoro-3,4-dihydro-2H-benzo[1,4]oxazin-5-ylcarbamoyl)ethyl]carbamic acid tert-butyl ester

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Reaction Steps

To an ice-cooled mixture of 8-fluoro-3,4-dihydro-2H-benzo[1,4]oxazin-5-ylamine (243 mg, 1.445 mmol), (S)-2-tert-butoxycarbonylaminopropionic acid (305 mg, 1.61 mmol) and HOAt (200 mg, 1.463 mmol) in DCM (15 mL) was added EDCI HCl (337 mg, 1.76 mmol). The reaction mixture was stirred in the ice bath for 90 min, then diluted with DCM, washed with aqueous Na2CO3 and then water. The organic layer was dried (Na2SO4) and then concentrated in vacuo. The resulting residue was purified by column chromatography (Si—PCC, gradient 50-70% EtOAc in cyclohexane) affording the title compound as a pale yellow foam (440 mg, 89%). LCMS (Method B): RT 3.02 min [M+H]+ 340

Provenance & Evidence