[Br:1][C:2]1[CH:17]=[C:16]([F:18])[CH:15]=[CH:14][C:3]=1[C:4]([C:6]1[CH:11]=[C:10](C)[CH:9]=[C:8]([CH3:13])[CH:7]=1)=[O:5].[OH:19]O>S(=O)(=O)(O)O>[CH3:4][C:6]1[CH:11]=[C:10]([OH:19])[CH:9]=[C:8]([CH3:13])[CH:7]=1.[Br:1][C:2]1[CH:17]=[C:16]([F:18])[CH:15]=[CH:14][C:3]=1[C:4]([OH:5])=[O:19]30.8 g (0 1 mol) of 2-bromo-4-fluoro-3',5'-dimethylbenzophenone were dissolved in 140 g of 90% sulfuric acid, and 5.7 g of 90% hydrogen peroxide solution were added dropwise (metering time 1 h) between -10° C. and 0° C. After subsequent stirring for 2 h, the mixture was poured on to 500 g of ice and then heated at the boil for 5 h. Isolation as described in Example 8 gave 9.6 g (0.079 mol, 79%) of 3,5-dimethylphenol and 15.6 g (0.071 mol, 71%) of 2-bromo-4-fluorobenzoic acid (crude, purity (GC) ca. 90%, melting point 160°-166° C.)
Wird geladen…
