Benzoyl thiophene

Dimethyl-thiophen 3-Phenyl-thiophen 2-Formyl-thiophen 2-Benzoyl-thiophen... 

Heterocyclic systems can also be reduced by this procedure. 2-benzoyl-thiophene and 3-methyl-thiophene undergo reduction to 2-benzyl-(72< )- and 3-methyl-thiophane (129), respectively86. Analogously, 1-methyl-cyclohexane (132) can be obtained from 1-methyl-1-cyclohexene88. ... 

Both NbCls and AgClOa can catalyse FC acylation reactions, but the yields are rather low. The combination of these salts is much more effective, and 2-benzoyl thiophene was obtained with 86% yield using only 1 mol% of NbCls and 3 mol% of AgClOa (Scheme 7) [27]. 

It has been shown that 2,3-thiophenedicarboxylic acid is preferentially esterified in the 2-position and the dimethyl ester is preferentially hydrolyzed in this position. The structure proof was difficult to achieve as rearrangements occurred. Thus both isomeric amides (195) and (196) were decarboxylized to the N-methylanilide of 3-thiophenecarboxylic acid (197). The same carbomethoxy benzoyl-thiophene, proved to be 2-carbomethoxy-3-benzoylthiophene (198),... 

A mixture of 10.3 g of thiophene-20 -methylacetic acid [prepared by process of Bercot-Vat-teroni, et al.. Bull. Soc. Chim. (1961) pp. 1820-211, 11.10 g of benzoyl chloride and a suspension of 23.73 g of aluminum chloride in 110 cc of chloroform was allowed to stand for 15 minutes and was then poured into a mixture of ice and hydrochloric acid. The chloroform phase was extracted with a 10% aqueous potassium carbonate solution and the aqueous alkaline phase was acidified with N hydrochloric acid and was then extracted with ether. The ether was evaporated off and the residue was crystallized from carbon tetrachloride to obtain a 54% yield of 5-benzoyl-thiophene-20 -methylacetic acid melting at 83°C to 85°C. The... 

The IR spectrum of thieno [ 2,3-A]thiophene (1) was first reported by Godart192 in 1937 in work devoted to the UV and IR spectral analysis of thiophene, thienothiophene 1, and benzo[A]thiophene. Comparison of spectral features in the 4000-11,000 cm 1 region of thiophene and benzene, tfiieno[2,3-6]thiophene (1) and naphthalene, and benzoyl-thiophene, benzene, and naphthalene demonstrated, in Godart s opinion, the similarity of IR spectra (in this region) of thiophene, thienothiophene 1, and benzo[A]thiophene, on the one hand, and benzene, thienothiophene 1, and naphthalene, on the other hand. The molecular absorption coefficients of benzene and thiophene, as well as of naphthalene and thienothiophene 1, were also similar. 

Thiophen-z-T acid, 25 °C (kinetic) Benzoyl nitrate—acetonitrile, 0-88 15... 

These results show that in the phenylation of thiazole with benzoyl peroxide two secondary reactions enter in competition the attack of thiazole by benzoyloxy radicals, leading to a mixture of thiazolyl benzoates, and the formation of dithiazolyle through attack of thiazole by the thiazolyl radicals resulting from hydrogen abstraction on the substrate and from the dimerization of these radicals. This last reaction is less important than in the case of thiophene but more important than in the case of pyridine (398). 

Thiophene is much more easily nitrated than benzene and it is therefore possible to use mild nitrating agents such as acetyl or benzoyl nitrate. Like pyrrole and furan the principal nitration product is the 2-derivative. The a selectivity decreases with increasing vigour of the reagent and up to 15% of the 3-isomer has been obtained. 

Thiophene is also readily acylated under both Friedel-Crafts and Vilsmeier-Haack conditions and similarly to pyrrole and furan gives 2-acylated products. An almost quantitative conversion of thiophene into its 2-benzoyl derivative is obtained by reaction with 2-benzoyloxypyridine and trifluoroacetic acid. The attempted preparation of 2-benzoylthiophene under standard Friedel-Crafts conditions, however, failed (80S139). 

Thiophene, 3-amino-2-benzoyl-4-cyano-5-hydroxy synthesis, 4, 927... 

Campaigne et al. have used 3-thenyl bromide obtained by benzoyl peroxide-catalyzed, side-chain bromination of 3-methylthiophene with A -bromosuccinimide, as a starting material for 3-substituted thiophenes. - 22 3-Methylthiophene is now prepared commercially from itaconic acid. The reactive halogen in 3-thenyl bromide could be directly reacted with a variety of nucleophiles, such as cyanide, or malonate, to give more complex 3-substituted compounds. 3-Thenyl bromide was converted by the Sommelet reaction to 3-thio-phenealdehyde which, with silver oxide, was oxidized to 3-thio-... 

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)... 

Some structure-activity relationships of a further developed R4, R5 alkyl/cycloalkyl series (2a-o, Fig. 10, Table 1) were also investigated. This study [69] revealed structural features that favored allosteric enhancing activity, such as benzoyl lipophilic substitution and thiophene 4-alkyl substitution, while other features, such as thiophene 5-bulky substitution, favored antagonistic properties. Upon further analysis, a... 

Electron-rich aromatic compounds such as durene, p-dimethoxybenzene, mesitylene, anisole, thiophene, and fluorene can be benzoylated or acetylated by the corresponding Af-acylimidazole in trifluoroacetic acid to give the corresponding benzophenone or acetophenone derivative in good yield (Method A). As the actual acylating agent, a mixed anhydride of trifluoroacetic acid and benzoic acid has been proposed 1973... 

Such nucleophilic displacements are likely to be addition-elimination reactions, whether or not radical anions are also interposed as intermediates. The addition of methoxide ion to 2-nitrofuran in methanol or dimethyl sulfoxide affords a deep red salt of the anion 69 PMR shows the 5-proton has the greatest upfield shift, the 3- and 4-protons remaining vinylic in type.18 7 The similar additions in the thiophene series are less complete, presumably because oxygen is relatively electronegative and the furan aromaticity relatively low. Additional electronegative substituents increase the rate of addition and a second nitro group makes it necessary to use stopped flow techniques of rate measurement.141 In contrast, one acyl group (benzoyl or carboxy) does not stabilize an addition product and seldom promotes nucleophilic substitution by weaker nucleophiles such as ammonia. Whereas... 

A similar process with benzalacetophenone results in different products, the chemoselectivity being controlled by the experimental conditions, namely the solvent and the supporting electrolyte used [261]. Either an acyclic disulfide, bis(2-benzoyl-l-phenylvinyl) disulfide (in Et0H-DMF/Mg(Cl04)2), or two isomeric thiophenes (in DMF/NaCl04) can thus be obtained (Scheme 63). Upon the substitution of a vinylic proton at C(2) with Br, the reaction becomes more regioselective and the only product now formed is an a,a -dibenzoyl thiophene derivative. 

The phenylation of thiophene with benzoyl peroxide gave a considerable amount of 2,2 -dithienyl one suggested mechanism involved the formation of 2-thienyl radicals by oxidation, and their subsequent dimerization. More recent studies indicate that the 2,2 -dithienyl is formed through an initial addition of benzoyloxy radicals to the thiophene nucleus followed by dimerization of the resulting radical and loss of two molecules of benzoic acid (Scheme 15). 

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