Thiophene compound

Benzisothiazoles also suffer N—S bond cleavage, following attack at sulfur, but 1,2-benzisothiazole 1,1-dioxides are cleaved at the C—N bond. Saccharin derivatives are attacked at the carbonyl function. In cases where N—S bond cleavage occurs, recyclization can sometimes occur, often producing thiophene compounds. 

The spectra and halochromism of thiophene analogs of triphenyl and diphenyl carbinol, " the spectra of anilides of 2- and 3-thenoyl-acetic acid, " and the fluorescence of some thiophene compounds have been investigated. 

Another elegant route to thiophene compounds has, during recent years, been worked out by Fiesselmann et In principle this... 

Many stilbenelike thiophene compounds have been prepared for a study of estrogenic activity, especially by Buu-Hoi et al. Thiophene derivatives of nonhydroxylated stilbene types showed no significant activitywhereas weak estrogenic activity was found in 5-acetyl-, 5-propionyl-, and 5-benzoyl-2-(-stilbenyl)thiophene. 1-Bromo-l,2-diphenyl-2-(5-bromo-2-thienyl)ethylene (258) was found to inhibit body growth and to produce extensive testicular atropy in male rats. A thiophene analog of estrogenic isoflavones (259)... 

Treatment of 2,7-di-/ert-butylthiepin (1) either directly with bromine at — 78 °C, or with pyridinium bromide perbromide at room temperature, gives the thiophene compound 2. In contrast, bromination with bromine-1,4-dioxane complex or pyridinium bromide perbromide in the presence of acetic acid leads to the thiopyran derivative 3.87 To account for these results a homothiopyrylium ion has been proposed as a common intermediate, formed by electrophilic bromination at C4 in the first step. 

On the contrary, for oil E the quantity of asphaltenes decreases from 8.1 for the initial crude oil to 4-1 for the sample produced at the end of the test (Fig. 12). Moreover, the amounts of resins + asphaltenes decreases whereas the amounts of saturates and aromatics increase (51 4 in the initial oil, 72.4 for a sample recovered at t = 24 h). The analysis by GC shows that each oil fraction is enriched in components with molecular chains ranging from 15 to 30 carbons which don t exist in the initial oil (n-alkanes, aromatics O q-CLq which are less complex than the initial ones, thiophenic compounds C -C ). The elemental... 

The patent described a method for the removal of thiophenic compounds from fossil fuels, in which the reacting media might contain organic solvents. Additionally, the biocatalyst may be contacted with the fuel directly either as free enzyme or in its immobilized form. The process could, therefore, be performed either in a batch reactor or in a semi-continuous or continuous manner. Further, it may be performed either as a stand... 

Finally, a more MB-oriented patent concerns a gene which participates in desulfurizing enzyme expression inhibition [107], The production of the microorganism which highly expresses the desulfurizing enzyme, even when cultured in the presence of a sulfate as only one sulfur source was included. The application was focused towards the decomposition of thiophene compounds. 

Tosi B, Bonora A, DalPOllio G and Bruni A (1991), Screening for toxic thiophene compounds from crude drugs of the family Compositae used in Northern Italy , Phytother Res, 5, 59-62. 

The synthesis of methylimidazole-thiophene compounds was reported by Santos et al. [46] and has been included for completeness, although no biological activity has been reported for these heterocycles. The formation of these imidizole-thiophenes (24a-d), occurs via the condensation of 2-formylthiophene (25) with benzil derivatives (26a-d) in the presence of ammonium acetate to yield the imidazole-thiophene compounds (27a-d). These compounds can then be N-methylated by treatment with iodomethane in... 

Membered Aromatic Rings a) Non-Fused Thiophene Compounds... 

In order to obtain asymmetric spiro compounds, there are two different possibilities. First, one can connect two different chromophores via a common spiro center. The thiophene compounds 39a and 39b are one example [84, 85]. Second, one can connect two equal but asymmetric chromophores. Based on this principle are Spiro-PBD (40), spiro-bridged bis(phenanthrolines) (41) [86], and the branched compounds Octol (42a) and Octo2 (42b) [87]. Because of their symmetry, these molecules are chiral. The glass transition temperatures of 40 and 42b are reported to be 163 and 236°C, respectively [88], Unfortunately, reports on the thermal properties of 39 and 41 are lacking. 

Despite the fact that earlier studies indicated little promise, the search for superior biologically and pharmacologically active thiophene compounds continued. 

It seems that, except in a few cases (antihistaminics), the biological and pharmacological activity of thiophene compounds is usually slightly lower than that of the corresponding benzene derivatives. The application of thiophene derivatives as chemotherapeutic agents seems to be fairly limited. 

Various unsaturated thiophene compounds were investigated viz., polyenes, polyenic acids and aldehydes and various acetylenic derivatives (59), (60), (76-81). 

Fredga, A., and K. Pettersson Optically Active Thiophene Compounds. II. Acta chem. scand. 4, 1306 (1950). 

Texaco Development Corp. Alkylated Thiophene Compounds. Brit. Patent... 

Thiophene and thiophene compounds from hquid fuel AgY, Cu(I)-Y/activated carbon, Cu(l)-SBA-15 [259-262]... 

Heterocyclic aromatics in fuel such as pyridine, indole and condensed thiophene compounds are known to darken fuel color. They have also been shown to lead to an increase in the deposit forming tendencies of fuel. Aromatic peroxides can also react to form higher-molecular-weight, sludgelike material in fuel. 

Substituents at C(2) and C(4) may affect the conformational equilibrium of 3-acyl derivatives of five-membered heterocycles and examples have been reported for furan, pyrrole, and thiophene compounds (81RCR336). Stabilizing electrostatic interactions may be the origin of the conformational behavior (80JST(67)251) of the thiophene derivatives 21 and 22, which adopt the conformation depicted. 

If the disulfides are methylpropenyl disulfide or propylpropenyl disulfide (Scheme 7.3a) this may lead to thiophene compounds [31,32]. This is not a very common process in freshly cut Allium species, but heating seems to promote this process [33, 34]. 

Like benzo derivatives of thiophene, compounds 63-68 exhibit a correlation between free valence and radical superdelocalizability within the individual classes of positions.18... 

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