[I:1][C:2]1[S:3][C:4]([C:7]2[S:8][C:9]([C:12]3[S:13][CH:14]=[CH:15][CH:16]=3)=[CH:10][CH:11]=2)=[CH:5][CH:6]=1.[Br:17]N1C(=O)CCC1=O>CO>[I:1][C:2]1[S:3][C:4]([C:7]2[S:8][C:9]([C:12]3[S:13][C:14]([Br:17])=[CH:15][CH:16]=3)=[CH:10][CH:11]=2)=[CH:5][CH:6]=1100 mg (0.27 mmol) of 2-iodo(5,2′:5′,2″-terthiophene) (1) obtained above in the first step of example 1 were diluted in 100 ml of methanol at 0° C. 2 equivalents of N-bromosuccinimide (NBS, 95 mg, 0.53 mmol) were then added. The mixture was left stirring, in the dark for 12 h. The solvent was then evaporated under reduced pressure. The crude product of the reaction was then purified by column chromatography using, as eluent, petroleum ether then a petroleum ether/dichloromethane (5/1: v/v) mixture. The expected product was isolated in the form of a yellow powder (115 mg; yield=95%).
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