35299-71-9Relevant articles and documents
Thiophene-based fluorescent mercury-sensors
Shigemoto, Austin K.,Virca, Carolyn N.,Underwood, Samuel J.,Shetterly, Lauren R.,McCormick, Theresa M.
, p. 2081 - 2089 (2016)
Coordination chemistry of thiophene rings is poorly understood, despite their common use in organic electronic materials. The absorption and emission responses to transition metal ions of three thiophene-based ligands containing pyridine chelating groups are examined. These ligands, 2-(2′-thienyl)-pyridine (L1), 2,5-bis(2-pyridyl)thiophene (L2), and 2,6-bis(2-thienyl)pyridine (L3), show a ratiometric fluorescence response in the presence of Hg(ClO4)2 with reasonable selectivity against many transition metal ions in acetonitrile. 1H NMR data support S,N chelation of L1 and L2 to the Hg(II) center, while L3 coordinates through cyclometalation via one carbon of thiophene. DFT calculations suggest thiophene coordinates to Hg(II) in a bent geometry. Our results indicate that thiophene could offer selectivity for Hg(II) towards the design of fluorescent sensors.
In search of oligo(2-thienyl)-substituted pyridine derivatives: A modular approach to di-, tri- and tetra(2-thienyl)pyridines
Bera, Mrinal K.,Hommes, Paul,Reissig, Hans-Ulrich
, p. 11838 - 11843 (2011)
Herein, we describe our attempts to systematically prepare a series of oligo(2-thienyl)-substituted pyridine derivatives. The crucial starting material, a β-alkoxy-β-ketoenamide, is easily available on a large scale by the reaction of lithiated methoxyallene with thiophene-2-carbonitrile and thiophene-2-carboxylic acid. This three-component reaction is followed by intramolecular cyclization to yield the suitably functionalized 2,6-di(2-thienyl)-substituted pyridine derivates. The two oxygen atoms allow the programmed activation of positions C-3, C-4, or C-5 of the pyridine ring to perform palladium-catalyzed coupling reactions with thiophene-2-boronic acid or 2-(tributylstannyl)thiophene, and alternatively, reductive removal of groups. With this concept, we were able to prepare five pyridine derivatives with 2-thienyl substituents in the 2,6-, 2,3,6-, 2,4,6-, 2,3,4,6-, and 2,3,5,6-positions. 2,3,4,5,6-Penta(2-thienyl)pyridine was not available with our methods. The UV/Vis and fluorescence spectra of all pyridines were recorded and showed a dependence on the substitution pattern and protonation state. For the protonated 2,3,5,6-tetra(2-thienyl)-substituted pyridine, a Stokes shift of about 180 nm with an emission at 515 nm was observed.
Ruthenium-catalyzed cyclization of ketoxime acetates with DMF for synthesis of symmetrical pyridines
Zhao, Mi-Na,Hui, Rong-Rong,Ren, Zhi-Hui,Wang, Yao-Yu,Guan, Zheng-Hui
, p. 3082 - 3085 (2014/06/23)
A novel ruthenium-catalyzed cyclization of ketoxime carboxylates with N,N-dimethylformamide (DMF) for the synthesis of tetrasubstituted symmetrical pyridines has been developed. A methyl carbon on DMF performed as a source of a one carbon synthon. And NaHSO3 plays a role in the reaction.
