[S:1]1[CH:5]=[CH:4][CH:3]=[C:2]1[C:6]1[S:7][C:8]([C:11]2[S:12][CH:13]=[CH:14][CH:15]=2)=[CH:9][CH:10]=1.C1C(=O)N([Br:23])C(=O)C1>CN(C=O)C.C(Cl)Cl>[Br:23][C:13]1[S:12][C:11]([C:8]2[S:7][C:6]([C:2]3[S:1][CH:5]=[CH:4][CH:3]=3)=[CH:10][CH:9]=2)=[CH:15][CH:14]=1Using 2,2′:5′,2″-terthiophene (7, FIG. 3): N-Bromosuccimide (3.147 mg, 17.681 mmol) were added portion in portions during 5 hours to an solution of 2,2′:5′,2″-terthiophene (4.315 g, 17.373 mmol) in 10 ml DMF at −20° C. After about 90 min, a precipitate was formed. After stirring for 14 hours at room temperature, the reaction mixture was dissolved in 300 ml CH2Cl2 and washed twice with 100 ml 1N HCl. The aqueous layers were extracted with CH2Cl2 and the organic layers were dried (MgSO4) and concentrated. Purification by FC (hexanes) gave 5.222 g (56 mmol, 92%) 5-bromo-2,2′:5′,2″-terthiophene, 92%) as yellow solid.
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