Reaktion #171848

Reaktionsgleichung

bromine

8-bromo-3,4-dihydro-2H-benzo[b]oxepin-5-one

bromine

→

title compound

Ausbeute 97.0%

4,8-Dibromo-3,4-dihydro-2H-benzo[b]oxepin-5-one

Ausbeute 97.0%

Lösungsmittel

diethyl ether

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturto warm up to RT
2. 2
   workup.STIRRINGstirred for 3 h
3. 3
   workup.STIRRINGstirring
4. 4
   workup.WAITwas pursued for 16 h
5. 5
   SonstigeThe solvent was removed in vacuo
6. 6
   Sonstigethe resultant residue was purified by flash chromatography (SiO2, 10% ethyl acetate in cyclohexane)

Vorschrift

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 (1 H, m), 7.26 (2 H, m), 4.94 (1 H, dd, J=7.7, 6.7 Hz), 4.43 (1 H, ddd, J=12.7, 5.6, 4.8 Hz), 4.25-4.15 (1 H, m), 2.97-2.86 (1 H, m), 2.51 (1 H, ddt, J=14.7, 7.7, 4.6 Hz).

Quelle