- Synthesis of 2-Organylchalcogenopheno[2,3-b]pyridines from Elemental Chalcogen and NaBH4/PEG-400 as a Reducing System: Antioxidant and Antinociceptive Properties
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An alternative method to prepare 2-organylchalcogenopheno[2,3-b]pyridines was developed by the insertion of chalcogen species (selenium, sulfur or tellurium), generated in situ, into 2-chloro-3-(organylethynyl)pyridines by using the NaBH4/PEG-4
- Peglow, Thiago J.,Bartz, Ricardo H.,Martins, Carolina C.,Belladona, Andrei L.,Luchese, Cristiane,Wilhelm, Ethel A.,Schumacher, Ricardo F.,Perin, Gelson
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- Access to functionalized thienopyridines via a reagent-capsule-assisted coupling, thiolation and cyclization cascade sequence
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Thienopyridines and related heterocycles were prepared in a straightforward manner in moderate to good yields and under mild conditions by palladium-catalysed cross-coupling of ortho-fluorinated iodopyridines and terminal alkynes, followed by a reagent-capsule-assisted thiolation cyclization process. By applying paraffin wax capsules to prevent catalyst poisoning and undesired side reactions, the separation and purification processes were reduced.
- Cai, Jialing,Huang, Shuo,He, Ruenfa,Chen, Lu,Chen, Donghan,Jiang, Shaohua,Li, Bin,Li, Yibiao
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supporting information
p. 333 - 337
(2017/01/13)
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- Synthesis of 2-(hetero)arylthieno[2,3-b] or [3,2-b]pyridines from 2,3-dihalopyridines, (hetero)arylalkynes, and Na2S. Further functionalizations
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A simple and efficient three-step methodology is described for the first time for the synthesis of 2-(hetero)arylthieno[2,3-b] or [3,2-b]pyridines. The first step is a Sonogashira coupling from 3-bromo-2-chloropyridine or 2-bromo-3-chloropyridine with several (hetero)arylalkynes to obtain the corresponding 2- or 3-chloro(hetero)arylethynylpyridines. These were cyclized by treatment with Na2S affording the expected 2-(hetero) arylthienopyridines. As an improvement, these reactions were also performed in one-pot, without the isolation of the Sonogashira product, giving the thienopyridines in similar or better yields, reducing significantly the reaction time after the addition of Na2S. Further functionalizations were achieved in the thienopyridine system either by bromination in the thiophene ring or chlorination in the pyridine ring via a N-oxide intermediate, allowing metal-catalyzed coupling reactions and/or nucleophilic substitutions. The functionalization of some substituents is also possible and as an example a 1,3-diarylurea was obtained from the reaction of an aniline derivative with an arylisocyanate.
- Peixoto, Daniela,Begouin, Agathe,Queiroz, Maria-Jo?o R.P.
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p. 7082 - 7094
(2012/08/28)
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- One-pot synthesis of amine-substituted aryl sulfides and benzo[ b ]thiophene derivatives
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A series of amine-substituted aryl sulfides have been synthesized from nitroaryl halides via a simple one-pot procedure involving metal-free C-S cross-coupling and in situ nitro group reduction. Various nitroaryl halides were reacted with thiols in recyclable poly(ethylene glycol) to afford the amine-substituted aryl sulfides in high yield. Additionally, the cross-coupling reactions of nitro- and aldehyde-substituted aryl halides with benzyl thiols under the same reaction conditions were demonstrated to afford benzothiazole and phenylbenzo[b]thiophene derivatives.
- Duan, Zhongyu,Ranjit, Sadananda,Liu, Xiaogang
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supporting information; experimental part
p. 2430 - 2433
(2010/07/10)
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- Cascade synthesis of new tetracyclic heteroaromatic thieno[2,3-b]pyridine- containing ring systems
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Flash vacuum pyrolysis of appropriate stabilised ylides, prepared in a few steps from 2-(methylthio)nicotinic acid, give products containing previously unknown naphtho-, phenanthro-, benzothieno-and benzofuro-fused thieno[2,3-b]pyridine ring systems.
- Aitken, R. Alan,Garnett, Alasdair N.
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experimental part
p. 2402 - 2404
(2010/03/03)
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- CONDENSED HETEROAROMATIC RING SYSTEMS. VII. SYNTHESIS OF THIENOPYRIDINES, THIENOPYRIMIDINES, AND FUROPYRIDINES FROM o-SUBSTITUTED N-HETEROARYLACETYLENES
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The cross-coupling reaction of 2-chloro-3-iodo- and 4-chloro-3iodopyridines with phenylacetylene in the presence of dichlorobis(triphenylphosphine)palladium occured at the 3-position.The 3-ethynylpyridines containing an adjacent chloro group were converti
- Sakamoto, Takao,Kondo, Yoshinori,Watanabe, Ryo,Yamanaka, Hiroshi
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p. 2719 - 2724
(2007/10/02)
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