Boron tribromide → 6-[({1-[2-(6-Hydroxy-3-oxo-2,3-dihydro-4H-1,4-benzoxazin-4-yl)ethyl]piperidin-4-yl)amino)methyl]-2H-pyrido[3,2-b][1,4]oxazin-3(4H)-one

Participants

Reaction Steps

A solution of 6-[({1-[2-(6-methoxy-3-oxo-2,3-dihydro-4H-1,4-benzoxazin-4-yl)ethyl]piperidin-4-yl}amino)methyl]-2H-pyrido[3,2-b][1,4]oxazin-3(4H)-one (Example 22) (100 mg, 0.21 mmol) in dichloromethane was cooled to −78° C. and treated with 1M boron tribromide (0.63 mL, 0.63 mmol) dropwise. The reaction mixture was stirred at room temperature overnight. The reaction mixture was cooled to −78° C. and an additional 1 equivalent of 1M boron tribromide was added. The reaction was stirred for 4 hours at room temperature, and then quenched with saturated sodium bicarbonate. The organic layer was separated and the aqueous phase was extracted three times with dichloromethane. The combined organic extracts were dried over magnesium sulfate and concentrated to dryness under reduced pressure to afford crude product, 11 mg (11%), as a solid.

Provenance & Evidence