- Visible Light Induced Aerobic Coupling of Arylboronic Acids Promoted by Hydrazone
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A visible-light-induced oxidative coupling of arylboronic acids has been developed for the synthesis of biaryls. The reaction that employs polydentate hydrazones as the bifunctional catalyst works smoothly under room temperature. It is compatible with a w
- Xia, Hongyu,Wang, Ganghu,Zhao, Dongbo,Zhu, Chunyin
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supporting information
p. 922 - 929
(2022/02/10)
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- Determination of the binding constants of propeller-like metal complexes of picolinaldehyde-2-pyridylhydrazone
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Herein, we determined the binding constants for transition metal complexes of Cu2+, Co2+, Fe2+, Ni2+, and Zn2+ ions formed with the ligand picolinaldehyde-2-pyridylhydrazone (PapyH) using the Benesi-Hildebrand method. Stoichiometry 2:1 (ligand: metal) was previously determined by the Job's method and confirmed by single-crystal X-ray diffraction finding a propeller-like structure of the [Fe(Papy)2] compound. PapyH and the metal complexes were characterized by 1H NMR and UV-Vis spectroscopy, respectively. The Cu2+ complex exhibited the highest stability constant, which was confirmed by competitive reaction of different metal ions with the ligand PapyH.
- Carmona-Vargas, Christian C.,Aristizábal, Sandra L.,Belalcázar, María I.,D'Vries, Richard F.,Chaur, Manuel N.
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p. 275 - 280
(2019/01/04)
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- Synthesis, Biological Activity, and Mechanism of Action of 2-Pyrazyl and Pyridylhydrazone Derivatives, New Classes of Antileishmanial Agents
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In this work, we report the antileishmanial activity of 23 compounds based on 2-pyrazyl and 2-pyridylhydrazone derivatives. The compounds were tested against the promastigotes of Leishmania amazonensis and L. braziliensis, murine macrophages, and intracellular L. amazonensis amastigotes. The most potent antileishmanial compound was selected for investigation into its mechanism of action. Among the evaluated compounds, five derivatives [(E)-3-((2-(pyridin-2-yl)hydrazono)methyl)benzene-1,2-diol (2 b), (E)-4-((2-(pyridin-2-yl)hydrazono)methyl)benzene-1,3-diol (2 c), (E)-4-nitro-2-((2-(pyrazin-2-yl)hydrazono)methyl)phenol (2 s), (E)-2-(2-(pyridin-2-ylmethylene)hydrazinyl)pyrazine (2 u), and (E)-2-(2-((5-nitrofuran-2-yl)methylene)hydrazinyl)pyrazine (2 v)] exhibited significant activity against L. amazonensis amastigote forms, with IC50 values below 20 μm. The majority of the compounds did not show any toxic effect on murine macrophages. Preliminary studies on the mode of action of members of this hydrazine-derived series indicate that the accumulation of reactive oxygen species (ROS) and disruption of parasite mitochondrial function are important for the pharmacological effect on L. amazonensis promastigotes.
- Coimbra, Elaine S.,Antinarelli, Luciana M. R.,de A. Crispi, Mariana,Nogueira, Thais C. M.,Pinheiro, Alessandra C.,de Souza, Marcus V. N.
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p. 1387 - 1394
(2018/07/29)
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- Configurational and constitutional information storage: Multiple dynamics in systems based on pyridyl and acyl hydrazones
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The C=N group of hydrazones can undergo E/Z isomerization both photochemically and thermally, allowing the generation of a closed process that can be tuned by either of these two physical stimuli. On the other hand, hydrazine-exchange reactions enable a constitutional change in a given hydrazone. The two classes of processes: 1) configurational (physically stimulated) and 2) constitutional (chemically stimulated) give access to short-term and long-term information storage, respectively. Such transformations are reported herein for two hydrazones (bis-pyridyl hydrazone and 2-pyridinecarboxaldehyde phenylhydrazone) that undergo a closed, chemically or physically driven process, and, in addition, can be locked or unlocked at will by metal-ion coordination or removal. These features also extend to acyl hydrazones derived from 2-pyridinecarboxaldehyde. Similarly to the terpydine-like hydrazones, such acyl hydrazones can undergo both constitutional and configurational changes, as well as metal-ion coordination. All these types of hydrazones represent dynamic systems capable of acting as multiple state molecular devices, in which the presence of coordination sites furthermore allows the metal ion-controlled locking and unlocking of the interconversion of the different states.
- Chaur, Manuel N.,Collado, Daniel,Lehn, Jean-Marie
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body text
p. 248 - 258
(2011/03/21)
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- Synthesis and evaluation of analgesic, antiinflammatory and antiplatelet properties of new 2-pyridylarylhydrazone derivatives
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This work describes recent results from our research program aiming at the synthesis and pharmacological evaluation of new compounds acting as antiinflammatory, analgesic and platelet antiaggregatory. In this paper the synthesis and the pharmacological profile as analgesic, antiinflammatory and anti-platelet of new functionalized 2-pyridylarylhydrazone derivatives 5a-r are discussed. This class of N-heterocyclic derivatives represents a new series of prototype candidates with analgesic and antiinflammatory properties possessing also an important anti-aggregating activity. The pharmacological results herein disclosed suggest that the anti-inflammatory and analgesic activities of these new pyridynehydrazone derivatives observed in the carrageenan pleurisy model and acetic acid writhing test, respectively, is probably due to an interference on the arachidonic acid (AA) metabolism. The most important antiinflammatory derivative 2-(2-formylfurane)pyridylhydrazone 5p presented a 79% inhibition of pleurisy at a dose of 80.1 μmol/kg. We also described the results concerning the mechanism of action of this series of N-heterocyclic derivatives in platelet aggregation which suggest a Ca2+ participation, probably by a complexation scavenger mechanism. Compound 2-(2-formylfurane)pyridylhydrazone 5p was able to complex Ca2+ in in vitro experiments at 100 μM concentration, indicating that this series of compounds can act as Ca2+ scavenger depending on the nature of the aryl moiety present at the imine subunit.
- Todeschini, Adriane R.,De Miranda, Ana Luisa P.,Da Silva, Kelly Christine M.,Parrini, Sergio C.,Barreiro, Eliezer J.
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p. 189 - 199
(2007/10/03)
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- Stereoisomerization in Heterocyclic Hydrazones Derived from 2-Acylpyridines and their Oxidative Cyclization with Mercury(II) Acetate and Lead Tetra-acetate to Fused 1,2,4-Triazoles and 1,2,3-Triazolium Systems
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Hydrazones prepared by coupling 2-acylpyridines with arylhydrazines were isolated predominantly as E-isomers when the acyl substituent R was small (H or Me).When R was a phenyl group significant yields of Z-isomers, containing an intramolecular hydrogen b
- Butler, Richard N.,Johnston, Sean M.
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p. 2109 - 2116
(2007/10/02)
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