3,3'-Dibromo-2,2'-bithiophene

Colorless solid

The freshly prepared LDA solution (prepared by the addition ofn-BuLi (2.5 M in hexanes, 100 mmol, 40 mL) and diisopropylamine(11.1 g, 110 mmol) in 50 mL of anhydrous THF (78 C to roomtemperature)) was added drop wise to a solution of 3-bromothiophene (16.30 g, 100 mmol) in anhydrous THF (100 mL)at 78 C under nitrogen atmosphere. The reaction mixture wasstirred for 1 h at 78 C and CuCl2 (14.11 g, 105 mmol)was added inone portion. The reaction mixture was allowed towarm up to roomtemperature and treated with aqueous HCl. The organic phaseseparated was collected and the aqueous phase was extracted withdiethyl ether several times. The combined organic phase was driedover anhydrous Na2SO4 and the solution was filtered, concentratedand the residue was purified by silica gel column chromatography(hexane eluent) to afford a the required compound as white solid(yield 85percent).1H NMR (500 MHz, CDCl3, d ppm): 7.08 (d, J 5.0 Hz, 2H), 7.40(d, J 5.0 Hz, 2H).Example la - Lithium diisopropylamide (LDA) was prepared by the addition of n-BuLi (2.5 M in hexanes, 0.210 mol, 84 mL) to a solution of diisopropylamine (0.231 mol, 23.37 g) in 25 mL of anhydrous THF (-78 °C to room temperature). This LDA solution was added dropwise to a solution of 3-bromothiophene (0.200 mol, 32.607 g) in 200 mL of anhydrous THF cooled in acetone/dry ice bath. After stirring for 5 minutes precipitation was observed. The reaction mixture was stirred for 1 h and CuClExample la - Lithium diisopropylamide (LDA) was prepared by the addition of n-BuLi (2.5 M in hexanes, 0.210 mol, 84 mL) to a solution of diisopropylamine (0.231 mol, 23.37 g) in 25 mL of anhydrous THF (-78 °C to room temperature). This LDA solution was added dropwise to a solution of 3-bromothiophene (0.200 mol, 32.607 g) in 200 mL of anhydrous THF cooled in acetone/dry ice bath. After stirring for 5 minutes precipitation was observed. The reaction mixture was stirred for 1 h and CuClIn a 250 mL three neckflask, 3-bromothiophene (4.0 g, 24.54 mmol) was solved in anhydrous THF (50 mL). The solution was cooled to −78C and LDA solution was added dropwise over 20 min. Then the solution was stirred for 1 h at the same temperature and CuCl2 (6.56 g, 49.08 mmol) was added in one portion. After being stirred for 1 h at−78 °C, the mixture was warmed to room temperature and stirred for another 5 h. The reaction was quenched with water. The crude compound was extracted with dichloromethane and washed by distilled water, dried over anhydrous MgSO4, and evaporated in vacuum. The residue was purified by silica gel column chromatography (eluent: petroleum ether). Compound 2 was obtained as a white solid (1.7 g, 42percent).1H NMR (CDCl3, 400 MHz): 7.41 (d, J = 5.4 Hz, 2H, SCH), 7.08 (d, J = 5.4 Hz, 2H, SCCH).In a 250mL three neck flask, 3-bromothiophene (4.0g, 24.54mmol) was solved in anhydrous THF (50mL). The solution was cooled to −78°C and LDA solution was added dropwise over 20min. Then the solution was stirred for 1h at the same temperature and CuCl3, 3′-dibromo-2, 2′-bithiophene (11)Compound 1 (25.00 g, 51.8 mmol) was added to a refluxingdispersion of zinc powder (13.00 g, 0.3 mol) in a mixing solution of 150 mL ethanol, 30 mL water, 60 mL glacial acetic acid and 5 mL3 M HCl. After refluxing for an additional 6 h and then cooling toroom temperature, the mixture was filtered and washed threetimes with ethanol. The solvent was then removed by evaporationand water was added. The mixture was then extracted with diethylether and then dried over anhydrous MgSO4. The solvent wasremoved by evaporation, and the crude product was recrystallizedin hexane to afford colorless crystals (14.54 g, 86.3percent). 1H NMR(CDCl3), δ (ppm): 7.41 (d, J 5.5 Hz, 2H), 7.09 (d, J 5.0 Hz, 2H).Add to 250mL three-neck bottle9.64 g (0.02 mol) of 2, 2', 4, 4'-tetrabromobisthiophene, 1.96 g (0.03 mol)Zinc powder and 3.60 g (0.06 mol) of acetic acid, Nitrogen protection, Add 50g of ethanol with stirring, Heating to 70 ° C, 3.65 g of 10percent by mass (0.01 mol) of dilute hydrochloric acid was added dropwise.The system has bubble generation, After the addition is completed, the reaction is continued for 3 hours.Dropped to 50 ° C, The filtrate was cooled to 0 ° C.Precipitating a white solid, Filtering, the filter cake is dried in a vacuum oven at 50 ° C.Yielding 5.52 g of a white solid.Yield: 85.1percent.To a solution of 3, 3 ', 5, 5'-tetrabromo-2, 2'-bis (trifluoromethyl) bipyridine was added to zinc powder (12.5 g, 25.9 mmol), 130 ml of ethanol, 13 ml of water, 31 ml of acetic acid, Thiophene (3, 3 ', 5, 5'-Tetrabromo-2, 2'-bithiophene) was added. After the addition, the mixture was stirred for 2 hours, cooled to room temperature, filtered and washed with ethanol three times. The combined organic filtrates were evaporated and 300 to 400 ml of water were added. The precipitate was filtered, washed with water and dried in air. After recrystallization, Compound 15 (2.72 g, 64percent) was obtained via hot hexane.

3,3'-Dibromo-2,2'-dithiophene is used in the preparation of benzothiadiazole copolymers which direct charge transport in thin-film transistors. Used in the synthesis of solar cells which are dithienop yrrole / anthracene based. suzuki reaction

Molecular Weight:324.1
XLogP3:4.4
Hydrogen Bond Acceptor Count:2
Rotatable Bond Count:1
Exact Mass:323.81007
Monoisotopic Mass:321.81212
Topological Polar Surface Area:56.5
Heavy Atom Count:12
Complexity:147
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes