Please use this identifier to cite or link to this item: http://hdl.handle.net/1822/22010

TitleSynthesis of 2-(hetero)arylthieno[2,3-b] or [3,2-b]pyridines from 2,3-dihalopyridines, (hetero)arylalkynes and Na2S. Further functionalizations
Author(s)Peixoto, Daniela
Begouin, Agathe
Queiroz, Maria João R. P.
KeywordsThienopyridines
Sodium sulfide
Sonogashira coupling
Intramolecular cyclization
Halogenation
1,3-Diarylureas
Issue date23-Jun-2012
PublisherElsevier
JournalTetrahedron
Abstract(s)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.
TypeArticle
URIhttp://hdl.handle.net/1822/22010
DOI10.1016/j.tet.2012.06.057
ISSN0040-4020
Publisher versionhttp://www.journals.elsevier.com/tetrahedron/
Peer-Reviewedyes
AccessOpen access
Appears in Collections:CDQuim - Artigos (Papers)

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