Boron tribromide → 8-Hydroxy-2-methyl-3-oxo-3,4-dihydro-2H-benzo[b][1,4]oxazine-6-carbaldehyde

HRID 1184494Notes

Reaction equation

C[O:2][C:3]1[C:8]2[O:9][CH:10]([CH3:14])[C:11](=[O:13])[NH:12][C:7]=2[CH:6]=[C:5]([CH:15]=[O:16])[CH:4]=1.B(Br)(Br)Br>C(Cl)Cl>[OH:2][C:3]1[C:8]2[O:9][CH:10]([CH3:14])[C:11](=[O:13])[NH:12][C:7]=2[CH:6]=[C:5]([CH:15]=[O:16])[CH:4]=1

Participants

Conditions

Temperature: -10 °C

Procedure

In a 20 mL scintillation vial was added 8-methoxy-2-methyl-3-oxo-3,4-dihydro-2H-benzo[b][1,4]oxazine-6-carbaldehyde 17 (111 mg, 0.502 mmol) and boron tribromide (2.0 mL, 2.000 mmol) in DCM (2.5 mL) and stirred at −10° C. for 1 h then slowly warmed to 23° C. and stirred overnight. The reaction was quenched with MeOH, taken up in EtOAc, washed with water and brine, dried over MgSO4, and concentrated in vacuo to give the title compound as a tan solid (100 mg, 0.483 mmol, 96% yield). 1H NMR (400 MHz, DMSO-d6) δ ppm 1.45 (d, J=6.82 Hz, 3H) 4.75 (q, J=6.82 Hz, 1H) 6.92 (d, J=2.02 Hz, 1H) 7.03 (d, J=1.77 Hz, 1H) 9.74 (s, 1H) 9.98 (br. s., 1H) 10.85 (s, 1H). ESI-MS: m/z 208.0 (M+H)+.

Workup

temperaturethen slowly warmed to 23° C.
stirringstirred overnight
customThe reaction was quenched with MeOH
washwashed with water and brine
dry with materialdried over MgSO4
concentrationconcentrated in vacuo

Sources & evidence

ORD record: ord-d6f2f54dc41847c3ac56b79d8073b881
Source dataset: uspto-grants-2014_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08669249B2

Reaction notes

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