Trimethylaluminum → 7-bromo-4-[(4,6-dimethyl-2-oxo-1,2-dihydropyridin-3-yl)methyl]-6-methyl-3,4-dihydro-1,4-benzoxazepin-5(2H)-one

Participants

Reaction Steps

To a solution of methyl 3-bromo-6-(2-{[(4,6-dimethyl-2-oxo-1,2-dihydropyridin-3-yl)methyl]amino}ethoxy)-2-methylbenzoate (126c, 134 mg, 0.317 mmol) in 1,4-dioxane (1 mL) was added trimethylaluminum (2.0M in heptanes, 32.0 mg, 0.440 mmol). The reaction mixture was stirred at room temperature for 30 minutes, heated at 55° C. for 2 hours, and then 75° C. for 4 hours. The reaction mixture was cooled to room temperature, the solvent removed under vacuum, and the residue was stirred vigorously with EtOAc (25 mL) and 10% aq. solution of Rochell's salts. Once the mixture became homogeneous, the layers were separated and the organic layer was purified directly by column chromatography (silica gel, (7N NH3 in MeOH) in EtOAc) to give 7-bromo-4-[(4,6-dimethyl-2-oxo-1,2-dihydropyridin-3-yl)methyl]-6-methyl-3,4-dihydro-1,4-benzoxazepin-5(2H)-one (126d, 36 mg, 27% yield) as a light tan solid.

Provenance & Evidence