[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([CH3:8])=[CH:4][C:3]=1[O:9][C:10](=[O:17])[C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1.[Br:18]N1C(=O)CCC1=O.C(OOC(=O)C1C=CC=CC=1)(=O)C1C=CC=CC=1.O>C(Cl)(Cl)(Cl)Cl.C(OCC)C>[Br:18][CH2:8][C:5]1[CH:6]=[CH:7][C:2]([Cl:1])=[C:3]([O:9][C:10](=[O:17])[C:11]2[CH:12]=[CH:13][CH:14]=[CH:15][CH:16]=2)[CH:4]=1A mixture of benzoic acid 2-chloro-5-methyl-phenyl ester (CAB02124, 2.47 g, 10.0 mmol), N-bromo-succinimide (1.96 g, 11.0 mmol) and dibenzoyl peroxide (10 mg) in carbon tetrachloride (25 mL) was heated to reflux for 1 hour (TLC-control). After cooling to room temperature water (50 mL) and diethyl ether (100 mL) were added. The organic layer was separated, washed with brine (20 mL), dried over sodium sulphate and concentrated under reduced pressure. The residue was purified by column chromatography (EtOAc:hexane, 1:40, Rf: 0.21). Yield: 2.012 g (62%) colourless oil, which solidified after a few hours (contains ca. 10% benzoic acid 5-dibromomethyl-2-chloro-phenyl ester).
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