7-bromo-2-methyl-3,4-dihydro-2H-benzo[b][1,4]oxazine

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Borane dimethyl sulfide complex (2 M solution in THF, 0.414 mL, 0.828 mmol) was added at room temperature to a solution of 7-bromo-2-methyl-2H-benzo[b][1,4]oxazin-3(4H)-one A-2 (100.0 mg, 0.414 mmol) in anhydrous THF (4.10 mL) under an atmosphere of argon. The reaction mixture was heated to reflux for 2 h, cooled to room temperature, quenched with methanol (1.0 mL), stirred for 30 mins and concentrated to dryness under reduced pressure. The crude residue was purified by flash column chromatography on silica gel (hexanes:ethyl acetate gradient) to give 7-bromo-2-methyl-3,4-dihydro-2H-benzo[b][1,4]oxazine A-3 (92.9 mg, Yield=98%). MS (ESI) [M+1]+ 228, 230. The reaction mixture was heated to reflux for 2 h quenched with methanol (1.0 mL) concentrated to dryness under reduced pressure The crude residue was purified by flash column chromatography on silica gel (hexanes:ethyl acetate gradient)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Borane dimethyl sulfide complex (2 M solution in THF, 0.414 mL, 0.828 mmol) was added at room temperature to a solution of 7-bromo-2-methyl-2H-benzo[b][1,4]oxazin-3(4H)-one A-2 (100.0 mg, 0.414 mmol) in anhydrous THF (4.10 mL) under an atmosphere of argon. The reaction mixture was heated to reflux for 2 h, cooled to room temperature, quenched with methanol (1.0 mL), stirred for 30 mins and concentrated to dryness under reduced pressure. The crude residue was purified by flash column chromatography on silica gel (hexanes:ethyl acetate gradient) to give 7-bromo-2-methyl-3,4-dihydro-2H-benzo[b][1,4]oxazine A-3 (92.9 mg, Yield=98%). MS (ESI) [M+1]+ 228, 230. The reaction mixture was heated to reflux for 2 h quenched with methanol (1.0 mL) concentrated to dryness under reduced pressure The crude residue was purified by flash column chromatography on silica gel (hexanes:ethyl acetate gradient)