Bithienyl

The acetylation and formylation of 2,2 -bithienyl give monosubstitution in the 5-position, - Disubstitution is easily achieved and, in some cases, difficult to avoid as the deactivating effect of a substituent is not very strongly transmitted to the other ring. The nitration of 2,2 -bithienyl has recently been studied. ... 

Instead of thiophenes the readily available di-2-thienylmethane can be used as a chain extender, introducing a nine carbon unit upon desulfurization. Similarly the two reactive positions of 2,2-bithienyl and 2,2, 5",2"-terthienyl have been utilized for the introduction of eight and twelve carbons, respectively. ... 

From Bidens species 5-metbyl 5 -butadienyl-2 -bithienyl (245) has been isolated, the constitution of which was eonfirmed synthetically. Another 2,2 -bithienyl derivative has been isolated as an additional nematodicidal principal of the roots of Tagetes, for which strueture (246) has been suggested. On the other hand Sorensen et aL have isolated from the thistles, Berkheya macrocepkala and Echinops spareocephalm, a compound with very similar UV and IR spectra as (246) for which they suggested structure (247), based on... 

It seems quite obvious that the thiophenes are related to the polyacetylenes which they accompany. This viewpoint has recently been illustrated by the formation of thiophenes from polyacetylenes and hydrogen sulfide under almost biological conditions. In a recent lecture summary, the preparation of terthienyl, junipal, and (241) from 1,4-disubstituted butadiynes and hydrogen sulfide is claimed. A large number of bithienyls have been prepared and their nemato-dicidal activity investigated. All the compounds with strong activity were found to be derivatives of 2,2 -bithienyl. ... 

Studies Related to Naturally Occurring Acetylene Compounds. XXX. The Synthesis of 5-Methyl-5 -(buta-l,3-dienyl)-2,2 -bithienyl. Acta Chem. Scand. 15, 2047 (1961). 

Dimitrakopoulos, C. D. Afzali-Ardakani, A. Furman, B. Kymissis, J. Purushothaman, S. 1997. Trans-trans-2,5-bis-[2- 5-(2,2 -bithienyl) ethenyl] thiophene Synthesis, characterization, thin film deposition and fabrication of organic field-effect transistors. Synth. Met. 89 193-197. 

Advantage has been taken of the aforementioned observations in the synthesis of a terthiophene natural product, arctic acid (147) [123]. Pd-catalyzed carbonylation of bromobisthiophene 25, obtained from the Kumada coupling of 2-thienylmagnesium bromide and 2,5-dibromothiophene, gave bithiophene ester 144, which was converted to iodide 145 by reaction with iodine and yellow mercuric oxide. Subsequent propynylation of 145 was then realized using the Sonogashira reaction with prop-l-yne to give bisthienyl alkyne 146, which was subsequently hydrolyzed to 5 -(l-propynyl)-2,2 -bithienyl-5-carboxylic acid (147), a natural product isolated from the root of Arctium lappa. 

The thermolysis of benzoyl peroxide in thiophene gives a complex mixture, with the phenylation products accounting for only 3%. Considerable amounts of 2,2 -bithienyl and products containing the benzoyloxy group are formed. The suggested mechanism is shown in Scheme 59, according to which the benzoyloxy radicals are efficiently trapped before fragmentation to C02 and phenyl radicals. 

Fig. 4 Resonant frequency changes with time due to repetitive FIA melamine injections, for the MIP-QCM chemosensor. Melamine concentration is indicated with number at each curve. Inset shows FIA calibration plots for (1) melamine and its interfering compounds, such as (2) ammeline, (3) cyanuric acid, and (4) cyromazine. Volume of the injected sample solution was 100 pL. The flow rate of the 1 mM FIC1 carrier solution was 35 pL min-1. The MIP film was prepared by electropolymerization of 0.3 mM bis(2,2 -bithienyl)-benzo-[18-crown-6]methane functional monomer and 0.3 mM 3,3 -bis[2,2 -bis(2,2 -bithiophene-5-yl)]thianaphthene cross-linking monomer, in the presence of 0.1 mM melamine, in the trihexyl(tetradecyl)phosphonium tris(pentafluor-oethy 1)-trifluorophosphate ionic liquid ACN (1 1 v/v) solution, which was 0.9 mM in trifluoroacetic acid (pH = 3.0). The melamine template was extracted from the MIP film with 0.01 M NaOH before the determinations (adapted from [134])...

Summarizing his group studies on thienyl ion radicals, Pedulli (1993) described the behavior of oligothiophenes upon one-electron transfer. For the anion radical of 2,2 -bithienyl, the ESR spectrum shows the presence of two species with relative concentrations of 4 1 identified as the rotational isomers of this anion radical. According to ESR (Pedulli... 

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