4-Methylmorpholine → (S)-tert-butyl 1-(3-bromo-2-(5-fluoropyridin-3-ylamino)phenylamino)-1-oxopropan-2-ylcarbamate

Participants

Reaction Conditions

Reaction Steps

To a −10° C. solution (NaCl-ice bath) of Boc-L-Ala-OH (6.36 g, 33.6 mmol) and N-methylmorpholine (3.88 mL, 35.3 mmol) in DCM (84 mL) was added isobutyl chloroformate (4.40 mL, 33.6 mmol). The resulting cloudy colorless mixture was stirred at −10° C. for 30 min. To the mixture was then added a solution of 6-bromo-N1-(5-fluoropyridin-3-yl)benzene-1,2-diamine (4.7437 g, 16.81 mmol) in DCM (84 mL). The resulting mixture was allowed to warm to rt with stirring. After 20 h, satd. NH4Cl (100 mL) was added to the mixture. The cloudy organic layer was separated. The aqueous mixture was extracted with DCM (1×100 mL) and the organic extracts concentrated in vacuo to provide a crude product. The crude material was absorbed onto a plug of silica gel and purified by chromatography through a Redi-Sep pre-packed silica gel column (120 g), eluting with a gradient of 0% to 100% DCM:MeOH:NH4OH (89:9:1) in DCM, to provide (S)-tert-butyl 1-(3-bromo-2-(5-fluoropyridin-3-ylamino)phenylamino)-1-oxopropan-2-ylcarbamate as orange solid: LC-MS (ESI) m/z 453.0 [M+H (79Br)]+ and 455.0 [M+H (81Br)]+.

Provenance & Evidence