Reaction #1833230

Reaction equation

cesium carbonate

3,5-Difluorobenzene-1,2-diol

water

Bromochloromethane

→

title compound

Yield 28.0%

4,6-Difluorobenzo[d][1,3]dioxole

Yield 28.0%

Solvents

N,N-dimethylformamide

diethyl ether

Conditions

Workup

1. 1
   Temperaturethe mixture was heated
2. 2
   workup.STIRRINGstirred at 60° C. for 19 h
3. 3
   TemperatureAfter cooling
4. 4
   ExtractionThe aqueous phase was extracted again with ether (50 mL)
5. 5
   WashThe combined extracts were washed with water (2×20 mL)
6. 6
   Washwashed with saturated NaCl (1×10 mL)
7. 7
   Dryingdried (Na2SO4)
8. 8
   OtherThe bulk of the ether was removed by atmospheric distillation through a 300 mm Vigreux column
9. 9
   workup.DISTILLATIONthe product was distilled at 70-90° C.

Procedure

3,5-Difluorobenzene-1,2-diol (10 g, 69 mmol) was dissolved in dry N,N-dimethylformamide (100 mL), treated with cesium carbonate (56 g, 170 mmol) and stirred for 30 min at 20° C. Bromochloromethane (12 g, 90 mmol) was added and the mixture was heated and stirred at 60° C. for 19 h. After cooling, the mixture was shaken with water (100 mL) and diethyl ether (100 mL). The aqueous phase was extracted again with ether (50 mL). The combined extracts were washed with water (2×20 mL), washed with saturated NaCl (1×10 mL) and dried (Na2SO4). The bulk of the ether was removed by atmospheric distillation through a 300 mm Vigreux column. The pressure was reduced to 75 mmHg and the product was distilled at 70-90° C. to give the title compound as a thick oil (3.0 g, 28%): 1H NMR (400 MHz, CDCl3) δ 6.45 (m, 1H), 6.42 (d, J=2.4 Hz, 1H), 6.39 (d, J=2.4 Hz, 1H), 6.02 (s, 2H); 19F NMR (376 MHz, CDCl3) δ −117.99, −135.90; EIMS m/z 158.

Source