Alkylation thiophene

Thiophene, 2-aeyl-3-amino-5-aryl-4-eyano-synthesis, 4, 897 Thiophene, alkenyl-synthesis, 4, 917 Thiophene, alkoxy-synthesis, 4, 929 Thiophene, 2-alkoxy-5-aryl-synthesis, 4, 929 Thiophene, alkyl-... 

The reduction of the C— Br and C—1 group moments from 1.10 and 0.90 in bromo- and iodo-benzene to about 0.80 and 0.50 in 2-bromo- and 2-iodo-thiophene has been ascribed to the larger weight of resonance forms such as (8) and (9) in the thiophene series. The chlorine, nuclear, quadrupole, resonance frequencies of chloro-substituted thiophenes are much higher than those of the corresponding benzene derivatives. This has been ascribed to a relayed inductive effect originating in the polarity of the C—S o-bond in thiophenes. The refractive indices, densities, and surface tension of thiophene, alkyl- and halo-thiophenes, and of some other derivatives have been... 

The Friedel-Crafts alkylation of 2,5-dimethylthiophene was also studied (57). In contradistinction to thiophene itself, it was reported that this substituted thiophene alkylated readily with only a minor amount of polymerization when an active halide such as t-butyl chloride was used. With less reactive halides, e.g. n-butyl chloride, some replacement of the methyl groups in 2,5-dimethylthiophene occurred and polymerization increased. 

Dibenzothiophene, 1,2,3,4-tetrahydro-4-keto-synthesis, 4, 905 Dibenzo thiophenes alkylation, 4, 724 Birch reduction, 4, 775 13C NMR, 4, 11 5,5-dioxides... 

Thiophene, alkyl-substituted furans, and especially pyrrole, undergo Mannich reactions. 

Both 2- and 3-alkoxybenzo(7>]thiophenes may be obtained by alkylation of the appropriate hydroxy derivative, but there are competing side reactions (70AHC(11)177). 2-Methoxy-benzo[7>] thiophene can be prepared by heating 2-bromobenzo[6]thiophene with sodium methoxide, and 3-methoxybenzo[6]thiophene is obtained by similar treatment of 3-bromobenzo[7>]thiophene. Alkylation of 3-hydroxybenzo[6]thiophene-2-carboxylic ester is more efficient, giving the 3-alkoxy derivative in good yield, and this in turn can be hydrolyzed and decarboxylated in adequate yields (equation 81). 

Dyes Aldehydes, ketones, phenols, terpenes, thiophene, alkyl sulphates, polychlorinated biphenyls... 

Thiophene alkylation by styrene, catalysed by combination of 5 mol% gold(ni) chloride with 15 mol% of silver hexafluoroantimonate in 1,2-dichloroethane at... 

The refractive indices, densities, and surface tension of thiophene, alkyl- and halo-thiophenes, and of some other derivatives have been... 

Wrobleski et al. [617, 942], in their work described at length above, also tested other CPs, including poly(3-alkyl-thiophenes) (alkyl = hexyl, octyl) and poly(3-thienyl acetates) with an acetate group, i.e. -CH2(C=0)R, (R= Me, Eth), at the 3-position of thiophene. They however found P(ANi) superior in anti-corrosion performance. Similarly, Kinlen et al. [944], in their work also described above, claimed the use of virtually all p-type CPs, and actively tested P(Py) and P(3-Me-T). Again, however, they found P(ANi) the most versatile. Among the many reasons for the superior performance of P(ANi) were the better match with the metal substrates, expressed through its Vqc and more facile processibility. 

R = Ph, Bn, pyridine, thiophene, alkyl, cycloalkyl, aster, ether, uracil, C-5 uracil,... 

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