[C:1]([C:3]1[O:4][C:5]2[CH:11]=[C:10]([CH3:12])[CH:9]=[CH:8][C:6]=2[N:7]=1)#[N:2].[Br:13]N1C(=O)CCC1=O.C(OOC(=O)C1C=CC=CC=1)(=O)C1C=CC=CC=1>C(Cl)(Cl)(Cl)Cl>[C:1]([C:3]1[O:4][C:5]2[CH:11]=[C:10]([CH2:12][Br:13])[CH:9]=[CH:8][C:6]=2[N:7]=1)#[N:2]To a stirred solution of 2-cyano-6-methylbenzoxazole (2.0 g, 12.66 mmol) in carbon tetrachloride (50 ml) at room temperature are added successively N-bromosuccinimide (2.37 g, 13.3 mmol) and benzoyl peroxide (30.7 mg, 0.13 mmol). The solution is irradiated with a sun-lamp for 2 hours and concentrated. The residue is dissolved in 500 ml of ether and the solution filtered. The filtrate is concentrated and subjected to HPLC (2% ethyl acetate in hexane) to afford 2-cyano-6-bromomethylbenzoxazole which is used directly in the next step.
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