1392013-74-9Relevant academic research and scientific papers
Access to functionalized thienopyridines via a reagent-capsule-assisted coupling, thiolation and cyclization cascade sequence
Cai, Jialing,Huang, Shuo,He, Ruenfa,Chen, Lu,Chen, Donghan,Jiang, Shaohua,Li, Bin,Li, Yibiao
supporting information, p. 333 - 337 (2017/01/13)
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.
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.
, 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.
