3- n-Butylthiophene

Oxidations of a number of thiophenes and a wide variety of alkyl- and aryl-substituted thiophenes by RuCyaq. Na(ClO) have been compared with similar oxidations effected stoicheiometrically by [MnO ]", the aim being the destruction of these compounds for environmental reasons. Some were totally oxidised to sulfate, but in many cases end-products were not identified, though 2-ethylthiophene gave 2-acetylthiophene and 2-n-butylthiophene gave 2-butyroylthiophene [115],... 

Cooked meat contains a large number of furan and thiophene compounds that constitute part of the flavor and aroma. (1-3) The composition of these compounds varies with the cooking method and water contents in the meat Two representative compounds, 2-n-butylthiophene (BT) and 2-n-heptylfuran (HF) (Fig. 1), have been found to induce increased activity of a major detoxification enzyme system called glutathione S-transferase (GST). Chemicals that induce increased activity of GST are often inhibitors of chemical-induced tumorigenesis in laboratory animals. In this study, the inhibitory effects of BT and HF on chemically induced preneoplastic and neoplastic changes were examined. 

Figure 2. The fast protein liquid chromatographic (FPLC) analysis of isoenzymes isolated from the liver of rats treated with cottonseed oil (Control), 2-n-butylthiophene (BT), and 2-n-heptylfuran (HF).

Publication Date July 29, 1994 doi 10.1021/bk-1994-0564.ch022 Table 4. Effects of 2-n-butylthiophene (BT) and 2-n-heptyIfuran (HF) on 4-(methylnitrosaniino)>l-(3-pyridyl)-l-butanone (NNK)-induced lung tumors ... 

Fig. 2. Mass spectrum of a-n-butylthiophene [V. Harms and V. Cermdk, Collection Czech. Chem. Commun. 24, 1602 (1959)]. (For better identification peaks below mass 97 are drawn by doubling their actual intensity.)...

The apphcation of monoiodothiophene for the synthesis of alkylthiophenes by Wurtz-Fittig reaction was later described, again by Meyer [77] thus treatment of iodothiophene with alkyl bromides in dry ether in the presence of sodium led to the synthesis of 2-methylthiophene (already isolated from coal tar) and 2-ethyl-, 2-n-propyl and 2- -butylthiophenes. The synthesis of diiodothiophene was also described in the same paper, albeit without any applications. 

The primary adducts, cyclohexadiene derivatives, formed by [4+2] cycloaddition of thiophene dioxides with dienophiles, may further undergo [4+2] cycloaddition with the dienophiles. Thus, the adducts 84 of 3,4-di-ferf-butylthiophene dioxide 83 with maleic anhydride and AT-phenylmaleimide further react with these dienophiles to give excellent yields of bis-adducts, which are composed of the endo-endo and endo-exo isomers, 85a and 85b (Scheme 49) [160]. A similar reaction was also observed with 3,4-dichlorothiophene 1,1-dioxide with N-butyl- and A-p-nitrophenylmaleimides (Scheme 50) [133]. The reaction of highly congested thiophene dioxides 87 with 4-phenyl-1,2,4-triazoline-3,5-dione provides a unique pyridazine synthesis since the bis-adducts 88 are converted into the corresponding pyridazines 89 in one pot and in good yields by treatment with KOH in methanol (Scheme 51) [174]. 

The secondary sulfonamido group (—SO2NHR) appears to have a partial orrAo-directing effect on lithiation. Thus treatment of A-ferf-butylthiophene-2-sulfonamide (117) with n-BuLi gives a mixture of the two dianions (118) and (119) (Equation (11)), Under kinetically controlled conditions, the ratio (118) (119) is 2.7 1, but on equilibration, (119) precipitates out from the mixture, thereby driving the equilibrium towards the 5-lithio isomer <9iJOC4260>. The directing effect of the anionic sulfonamide does not appear to be as pronounced as that of the anionic carboxamide. 

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