Thiophene 2- bromo-, Grignard reagent

Benzo[6]thiophene, 2-(aryloxymethyl)-3-chloromethyl-synthesis, 4, 872 Benzo[6]thiophene, 2-arylthio-synthesis, 4, 931 Benzo[6]thiophene, 2-bromo-reaction with potassamide, 4, 829-830 synthesis, 4, 934 Benzo[6]thiophene, 3-bromo-Grignard reagents, 4, 831 reactions, 4, 830 synthesis, 4, 934 Benzo[6]thiophene, 4-bromo-synthesis, 4, 878, 934 Benzo[6]thiophene, 5-bromo-electrophilic substitution, 4, 797 Benzo[6]thiophene, 6-bromo-synthesis, 4, 878, 934 Benzo[6]thiophene, 5-t-buty 1-3-methyl-synthesis, 4, 880... 

Bromo- and iodobenzo [6] thiophenes readily form Grignard reagents, which react in the usual manner with carbon dioxide84,... 

Phenylmagnesium bromide is prepared in the usual manner Org, Syntheses Coll. Vol. 1, 550 (1941)] from 52 g. (0.33 mole) of bromo-benzene and 7.2 g. (0.30 gram atom) of magnesium. To the solution of the Grignard reagent in ether is added a solution of 38.8 g. (0.2 mole) of Enthrone [Org. Syntheses Coll. Vol. 1, 60 (1941)] in dry thiophene-free benzene. Excess ice and dilute hydrochloric acid are added, the ether layer is separated, and the aqueous layer is extracted with ether. The combined ethereal solutions are washed with 12% aqueous alkali solution and water. The ether is evaporated, and the residue is steam-distilled. The residue from the steam-distillation vessel is taken up in ether, and the ether is evaporated. The residual syrup is heated with a mixture of 12% aqueous sodium hydroxide and 10 g. of sodium hydrosulfite. The mixture is cooled and diluted with ether the alkaline aqueous layer is separated and discarded the ethereal layer is washed thoroughly with water and the ether is evaporated. The residual 9-phenylanthracene is reciystallized from acetic acid to give 36 g. (71%) of product, m.p. 152-153°. 

Grignard reagents were formed with difficulty from both 5-bromo- and 5,5 -dibromo-2,2 -dithienylmethane they gave acids (71 and 81%, respectively) on carbonation.16 A carboxyl group attached to a thiophene ring has been decarboxylated with copper-quinoline (80%)39 bis(2-thienyl)alkanoic acids of general formula 83 decarboxylate quite readily on heating.40,107 In one case (83, R1 = Me R2 = H) the expected decarboxylation product was accompanied by a little of the dimer 84. 

Recently, D-A-based ter- and quaterthiophenes 2.82 (w = 1, 2) (Chart 1.18) endowed with A-ethylcarbazole and cyanoacrylic acid at each terminus were prepared for their utilization as the active component in dye-sensitized solar cells (DSSCs) [163]. Coupling of the Grignard reagent of 2-bromo-3-hexylthiophene and 3-iodo-9-A-ethylcarbazole yielded carbazole-substituted thiophene. 

Branched terthiophene 5.77 was synthesized by Kumada-type cross-coupling of the Grignard reagent of 2-bromo-5-TMS-thiophene and 2,3-dibromothiophene in 79% yield. Higher generation DOTs were... 

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