[Br:1][C:2]1[CH:17]=[CH:16][C:5]([O:6][C:7]2[CH:15]=[CH:14][CH:13]=[CH:12][C:8]=2[C:9]([OH:11])=[O:10])=[CH:4][CH:3]=1.O.[CH:19]1C=CC=C[CH:20]=1>C(O)C.S(=O)(=O)(O)O>[Br:1][C:2]1[CH:3]=[CH:4][C:5]([O:6][C:7]2[CH:15]=[CH:14][CH:13]=[CH:12][C:8]=2[C:9]([O:11][CH2:19][CH3:20])=[O:10])=[CH:16][CH:17]=1A mixture of 560.0 g of 2-(4-bromo-phenoxy)benzoic acid in 1,940 ml of absolute benzene, 218 ml of absolute ethanol and 32.6 ml of concentrated sulfuric acid is refluxed for 32 hours, the water formed being removed in a water separator. The reaction mixture is cooled to 10° and washed, with the addition of ice, with 1,000 ml of water, 500 ml of a 2 N aqueous sodium carbonate solution and then again with 1,000 ml of water. The organic phase is separated off, dried over magnesium sulfate and evaporated at 40° under a pressure of 11 mm Hg. The residue is distilled under a high vacuum and yields ethyl 2-(4-bromo-phenoxy)-benzoate, boiling point 140°-150°/0.05 mm Hg.
Wird geladen…
