3- Thiophenecarboxylic acid 2-alkyl

Fatty acids are prepared by acylating thiophene with acid chlorides and reducing the ketones (218) to alkylthiophenes according to Wolff-Kishner or Clemmensen. The latter are then acetylated and oxidized by hypochlorite to 5-alkyl-2-thiophenecarboxylic acids, > ... 

Polymers formed from the electropolymerization of 3-thiophenecarboxylic acid, 3-cyanothiophene, and 3-nitrothiophene are soluble in acetonitrile. In addition, substitution of alkyl groups with more than six carbon atoms at the 3-position of the thiophene molecule and subsequent polymerization renders the reduced form of the polymer soluble. Indeed, solubility increases with chain length of the alkyl group and the de-doped or reduced forms are truly soluble in solvents such as toluene, THF, and methylene chloride. ... 

Dihydroxythiophene probably exists completely in the dioxo form (thioanhydride), but 2,3-dihydroxy thiophene exists exclusively as 3-hydroxythiophene-2(57/)one (244a R = R = H, R = OH). 3,4-Dihydroxythiophene with an alkyl substituent at position 2 (or 5) exists as (247). 3,4-Dihydroxy-2-thiophenecarboxylic acid ethyl ester is best prepared by acid hydrolysis and... 

Methyl-branched fatty acids are found in lipid fractions of many plants and are very common in bacterial extracts. Sixteen branched fatty acids were produced by different synthetic methods, including alkylation and hydrolysis of oxazolines to obtain 2-alkyl fatty acids. This was achieved through desulfurization of alkyl-substituted thiophenecarboxylic acids for 4- and 6-alkyl fatty acids and the application of the Kolbe reaction of dioic acids to give alkyl branches at different positions of the chain... 

In addition to the various dithienothiophene polymers, the related thieno[3,4-h] thiophene (1) and its derivatives have received considerable attention. The first reported example was the alkyl-functionalized derivative, poly(2-decylthieno[3,4-h]thiophene) (73) reported by Pomerantz and Gu [109]. Polymer 73 was prepared by the FeCls oxidation of 2-decylthieno[3,4-l jthiophene, which was synthesized from 2-thiophenecarboxylic acid as illustrated in Scheme 12.16 [109,110]. Such methods produced a fairly high LLk material LLk = 90,000, M = 52,000, PDI =1.7) that was blue-green in color and soluble in a variety of organic solvents (CHCI3, THF, and chlorobenzene). Solvent cast films exhibited a transition at 925 nm with an onset at 1350 nm (F of 0.92 eV). FeCls-doped films gave a conductivity of 3.1 X 10 . Films doped with either I2 or NOBF4 gave lower conductivities (1.0—4.2 x 10 ). 

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