Bromine → 4,8-dibromo-3,4-dihydrobenzo[b]oxepin-5(2H)-one

HRID 628077Notes

Reaction equation

[Br:1][C:2]1[CH:3]=[CH:4][C:5]2[C:11](=[O:12])[CH2:10][CH2:9][CH2:8][O:7][C:6]=2[CH:13]=1.[Br:14]Br>C(OCC)C>[Br:14][CH:10]1[CH2:9][CH2:8][O:7][C:6]2[CH:13]=[C:2]([Br:1])[CH:3]=[CH:4][C:5]=2[C:11]1=[O:12]

Participants

Conditions

Temperature: 0 °C

Procedure

To a solution of 8-bromo-3,4-dihydro-2H-benzo[b]oxepin-5-one (1.2 g, 5 mmol) in diethyl ether (20 mL) at 0° C. was added bromine (257 μL, 5 mmol) dropwise under nitrogen. The reaction mixture was stirred at 0° C. for 1 h, allowed to warm up to RT and stirred for 3 h. Further bromine (50 μL, 0.97 mmol) was added and stirring was pursued for 16 h. The solvent was removed in vacuo and the resultant residue was purified by flash chromatography (SiO2, 10% ethyl acetate in cyclohexane) to give the title compound as a white solid (1.55 g, 97%). 1H NMR (CDCl3): 7.62 (1H, m), 7.26 (2H, m), 4.94 (1H, dd, J=7.7, 6.7 Hz), 4.43 (1H, ddd, J=12.7, 5.6, 4.8 Hz), 4.25-4.15 (1H, m), 2.97-2.86 (1H, m), 2.51 (1H, ddt, J=14.7, 7.7, 4.6 Hz).

Workup

temperatureto warm up to RT
stirringstirred for 3 h
stirringstirring
waitwas pursued for 16 h
customThe solvent was removed in vacuo
customthe resultant residue was purified by flash chromatography (SiO2, 10% ethyl acetate in cyclohexane)

Sources & evidence

ORD record: ord-949c975a82c8486082c653b5a2d69607
Source dataset: uspto-grants-2016_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09309265B2

Reaction notes

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