- Studies on the biological activity of some nitrothiophenes
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The biological activity of nineteen substituted thiophenes (3) have been assessed by evaluating the minimum inhibitory concentration required to inhibit the growth of E. coli, M. luteus and A. niger. The series displays a wide range of activities with 2-chloro-3,5-dinitrothiophene (3a) or 2-bromo-3,5- dinitrothiophene (3c) showing the highest activity against all three organisms, while the simplest compound of the series, 2-nitrothiophene (3s) shows the smallest activity in each case. The mode of action of 3a and 3c is thought to involve nucleophilic attack by intracellular thiols at the 2-position of the heterocyclic ring leading to displacement of halogen, but other active derivatives, such as 2,4-dinitrothiophene (3h) and 5-nitrothiophene-2- carbaldehyde (3d) which have no displaceable halogen or leaving group are thought to act by forming Meisenheimer complexes. The Royal Society of Chemistry 2006.
- Morley, John O.,Matthews, Thomas P.
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p. 359 - 366
(2008/01/27)
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- The synthesis of highly active thiophene ring-containing chromophore components for photonic polymers based on a newly designed route
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2-Aminothiophene derivatives are the key intermediates for the present synthesis. It is known that the synthesis of 2-aminothiophene is troublesome although it is a rather simple heterocycle. In this work, an early report was newly developed as a basis for the efficient synthesis of thiophene-ring-containing chromophore components for photonic polymers. 2-Amino-5-nitrothiophene and 2-amino-3,5-dinitrothiophene were synthesized in excellent yield. After diazotization, the 2-aminothiophene derivatives were directly treated with N-phenyldiethanolamine to afford two-electron push-pull compounds. A similar styryl compound was also prepared. All of these chromophore molecules have further polymerizable hydroxy groups on one end of the molecule. These compounds are currently showing interesting potential in making highly sensitive, nonlinear optical polymeric materials. The Royal Society of Chemistry 1999.
- Yuquan, Shen,Yuxia, Zhao,Zao, Li,Jianghong, Wang,Ling, Qiu,Shixiong, Liu,Jianfeng, Zhai,Jiayun, Zhou
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p. 3691 - 3695
(2007/10/03)
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- Azoles. Part 7. A Convenient Synthesis of Thienoimidazoles
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A number of 1-mono- and 1,2-di-protected 4-bromoimidazole-5-carbaldehydes, (7), (8), (11), and (13)-(15), reacted with ethyl thioglycollate in ethanol in the presence of sodium ethoxide to give the corresponding title compound, (16), (17), or (19)-(22), respectively (65-70percent yield).Shorter reaction times allowed intermediates to be isolated, e.g. (13) gave (20) (69percent) and (23) (12percent).Several attempts to obtain the parent system, 1H- or 3H-thienoimidazole, failed.Attempts to prepare the title compounds from imidazoles by several classical syntheses used for annelated thiophene systems (due to Tilak, Campaigne, and Krollpfeiffer) failed as did attempts to prepare imidazolethiols through chlorosulphonation or thiocyanation of imidazoles or via their reaction with 2,4-dinitrobenzenesulphenyl chloride.Several unsuccesful approaches to the title compounds from thiophenes are also described.
- Iddon, Brian,Khan, Nazir,Lim, Bee Lan
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p. 1457 - 1464
(2007/10/02)
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