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

HRID 1184512Notes

Reaction equation

B(Br)(Br)Br.C[O:6][C:7]1[C:12]2[O:13][CH:14]([CH3:18])[C:15](=[O:17])[NH:16][C:11]=2[CH:10]=[C:9]([CH:19]=[O:20])[CH:8]=1>C(Cl)Cl>[OH:6][C:7]1[C:12]2[O:13][CH:14]([CH3:18])[C:15](=[O:17])[NH:16][C:11]=2[CH:10]=[C:9]([CH:19]=[O:20])[CH:8]=1

Participants

Conditions

Temperature: 23 °C

Procedure

To a 200 mL round-bottomed flask cooled in an ice/brine bath was added BBr3 (3.4 g, 13.56 mmol) in DCM (30 mL) under N2. A solution of 17 in DCM (10 mL) was added drop-wise to the cooled BBr3 solution. The reaction was stirred under N2 for 1 hr, then allowed to warm to 23° C. After 2 hr, the reaction was poured over ice and the resulting solid was isolated by vacuum filtration, washed with water, and dried in vacuo to give a tan solid (0.722 g, 77% yield): 1H NMR (400 MHz, DMSO-d6) δ ppm 1.40-1.50 (m, 3H) 4.76 (q, J=6.74 Hz, 1H) 6.93 (d, J=2.02 Hz, 1H) 7.04 (d, J=2.02 Hz, 1H) 9.72-9.77 (m, 1H) 9.95-10.01 (m, 1H) 10.85 (s, 1H). ESI-MS: m/z 208.0 (M+H)+.

Workup

temperatureTo a 200 mL round-bottomed flask cooled in an ice/brine bath
waitAfter 2 hr
additionthe reaction was poured over ice
customthe resulting solid was isolated by vacuum filtration
washwashed with water
customdried in vacuo

Sources & evidence

ORD record: ord-d3ba603faa9f45e28a413eb6313bb9d5
Source dataset: uspto-grants-2014_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08669249B2

Reaction notes

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