1323111-64-3Relevant academic research and scientific papers
Synthesis of 2-(hetero)arylthieno[2,3-b] or [3,2-b]pyridines from 2,3-dihalopyridines, (hetero)arylalkynes, and Na2S. Further functionalizations
Peixoto, Daniela,Begouin, Agathe,Queiroz, Maria-Jo?o R.P.
experimental part, p. 7082 - 7094 (2012/08/28)
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.
Sequential hydration-condensation-double cyclization of pyridine-substituted 2-alkynylanilines: An efficient approach to quinoline-based heterocycles
Peng, Lijie,Wang, Honggen,Peng, Changlan,Ding, Ke,Zhu, Qiang
scheme or table, p. 1723 - 1732 (2011/07/09)
An environmentally benign and atom-economical process to construct a unique quinoline-based tetracyclic scaffold, through sequential hydration- condensation-double cyclization reactions, has been described. The reaction starts with readily available pyrid
