- Novel bipyrazolo[1,5-: A] pyridine luminogens with aggregation-induced emission enhancement properties
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A novel 3,3′-bipyrazolo[1,5-a]pyridine molecular scaffold was obtained as a product of serendipity. Both photophysical characterisations and HOMO-LUMO theoretical calculations indicate its potential as a promising fluorophore with notable intramolecular charge transfer. Nonetheless, the emission properties of this compound suffer from the typical aggregation-caused quenching effect. To overcome this situation, we introduced additional diaryl groups onto the skeleton and synthesised a series of 7,7′-diaryl-3,3′-bipyrazolo[1,5-a]pyridines via palladium-catalysed intermolecular C-H/C-H bond cross-coupling reaction in 35-62% yields. This series of tailor-made luminogens with twisted π-structures display aggregation-induced emission enhancement properties.
- Hsiao, Pu-Yen,Chu, Jean-Ho
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supporting information
p. 12281 - 12284
(2021/11/30)
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- Divergent and Regioselective Synthesis of Pyrazolo[1,5- a]pyridines and Imidazo[1,5- a]pyridines
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Nitrogenous heterocycles are ubiquitous in pharmaceuticals and drug-like compounds; however, regioselective synthesis has proved challenging. Herein we report our efforts to develop a regioselective method for the synthesis of pyrazolo[1,5-a]pyridines and the serendipitous discovery of a protocol for the regioselective formation of imidazo[1,5-a]pyridines. Together, these transformations allow for the rapid and selective formation of two important heterocyclic motifs from a common intermediate.
- Mennie, Katrina M.,Reutershan, Michael H.,White, Catherine,Adams, Bruce,Becker, Bridget,Deng, James,Katz, Jason D.,Lablue, Elisabeth,Margrey, Kaila,Saurí, Josep
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p. 4694 - 4698
(2021/06/28)
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- Unexpected cleavage of the Cpy-Cpybond in the reaction of 2,2′-bipyridine N,N′-diimines with acetylenes
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An unusual cleavage of the Cpy-Cpybond in the reaction of 2,2′-bipyridine N,N′-diimine and its C-methyl substituted derivatives with acetylenes is described. The effect of the solvent on the yield of 7,7′-bipyrazolo[1,5-a]pyridine-2,2′,3,3′-tetracarboxylates and the products of cleavage of the Cpy-Cpybond has been studied. The mechanism of the cleavage reaction is discussed on the basis of DFT calculations.
- Supranovich, Vyacheslav I.,Borodkin, Gennady I.,Vorob'Ev, Aleksey Yu.,Shubin, Vyacheslav G.
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supporting information
p. 5377 - 5380
(2015/02/02)
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- Acid-Catalyzed Reactions of 3-(Hydroxymethyl)- and 3-(1-Hydroxyethyl)pyrazolopyridines
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Treatment of 3-(hydroxymethyl)pyrazolopyridines with trifluoroacetic acid in refluxing dichloromethane led to the formation of bis(pyrazolopyrid-3-yl)methanes or bis pyrid-3-yl)>methyl ethers depending upon the concentration of trifluoroacetic acid.In contrast, similar treatment of 3-(1-hydroxyethyl)pyrazolopyridines gave a mixture of 3-vinylpyrazolopyridines and 1,3-bis(pyrazolopyrid-3-yl)-1-butenes.
- Miki, Yasuyoshi,Nakamura, Noriko,Hachiken, Hiroko,Takemura, Shoji
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p. 1739 - 1745
(2007/10/02)
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