1593-08-4Relevant articles and documents
Electron localisation in electrochemically reduced mono- and bi-nuclear rhenium(I) complexes with bridged polypyridyl ligands
Page, Simon E.,Flood, Amar,Gordon, Keith C.
, p. 1180 - 1187 (2002)
A number of mono- and bi-nuclear rhenium(I) complexes have been prepared and their physical properties, including the infrared spectra of the reduced complexes, have been studied. These compounds have the general formula [Re(CO)3Cl(L)] and [Cl(CO)3Re(μ-L)Re(CO)3Cl], where L can be 2,3-(2′,2″)-diquinolylquinoxaline, 6,7-dimethyl-2,3-(2′,2″)-diquinolylquinoxaline, 2,3-(2′,2″)-diquinolylbenzoquinoxaline, 6,7-dichloro-2,3-(2′,2″)-diquinolylquinoxaline, 2,3-(2′,2″)-diquinoxalylquinoxaline, 6,7-dimethyl-2,3-(2′,2″)-diquinoxalylquinoxaline, 2,3-(2′,2″)-diquinoxalylbenzoquinoxaline and 6,7-dichloro-2,3-(2′,2″)-diquinoxalylquinoxaline. The electrochemical studies show that the first reduction potential of the free ligands correlates with the reductions of the corresponding mono- and bi-nuclear complexes. The properties of the complexes have been modelled using semi-empirical methods. These show linear correlations between: (a) the energy of the MLCT transitions versus the difference in energy between the LUMO and the HOMO and (b) the change in carbonyl force constant with reduction vs. the wavefunction amplitude of the π* LUMO at the site of coordination. The experimental data and calculations point to significant alterations in the π* LUMO with substitution at the ligand and with the chelation of a second Re(I) center.
Towards echinomycin mimetics by grafting quinoxaline residues on glycophane scaffolds
Jarikote, Dilip V.,Li, Wei,Jiang, Tao,Eriksson, Leif A.,Murphy, Paul V.
, p. 826 - 835 (2011)
Echinomycin is a natural depsipeptide, which is a bisintercalator, inserting quinoxaline units preferentially adjacent to CG base pairs of DNA. Herein the design and synthesis of echinomycin mimetics based on grafting of two quinoxaline residues onto a macrocyclic scaffold (glycophane) is addressed. Binding of the compounds to calf-thymus DNA was studied using UV-vis and steady state fluorescence spectroscopy, as well as thermal denaturation. An interesting observation was enhancement of fluorescence emission for the peptidomimetics on binding to DNA, which contrasted with observations for echinomycin. Molecular dynamics simulations were exploited to explore in more detail if bis-intercalation to DNA was possible for one of the glycophanes. Bis-intercalating echinomycin complexes with DNA were found to be stable during 20 ns simulations at 298 K. However, the MD simulations of a glycophane complexed with a DNA octamer displayed very different behaviour to echinomycin and its quinoxaline units were found to rapidly migrate out from the intercalation site. Release of bis-intercalation strain occurred with only one of the quinoxaline chromophores remaining intercalated throughout the simulation. The distance between the quinoxaline residues in the glycophane at the end of the MD simulation was 7.3-7.5 , whereas in echinomycin, the distance between the residues was ～11 , suggesting that longer glycophane scaffolds would be required to generate bis-intercalating echinomycin mimetics.
Synthesis, crystal structures, and fluorescent properties of zinc(II) complexes with benzazino-2-carboxalidin-2-aminophenols
Nosova, Emiliya,Stupina, Tatyana,Chupakhin, Artem,Lipunova, Galina,Valova, Marina,Slepukhin, Pavel,Charushin, Valery
, p. 61 - 67 (2015)
Complexes ZnL2 with novel fluorinated benzazines as tridentate ligands (HL = 6,7-difluoroquinoxalinand 6,7-difluoroquinolincarboxalidin-2-aminophenol) have been prepared. The photophisical properties of the ligands and the complexes has been studied.
Copper-Catalyzed Aerobic Oxidation of Azinylmethanes for Access to Trifluoromethylazinylols
Zheng, Gang,Liu, Hao,Wang, Mang
, p. 519 - 523 (2016)
A copper-catalyzed oxygenation of methylazaarenes was found to occur in the absence of both ligand and additive, and has been successfully employed for the synthesis of trifluoromethylazinylketols. This synthetic strategy incorporates aerobic oxidation and a trifluoromethylation in one-pot and provides a novel method for the trifluoromethylation of aliphatic C-H bond.
Iodine-imine Synergistic Promoted Povarov-Type Multicomponent Reaction for the Synthesis of 2,2′-Biquinolines and Their Application to a Copper/Ligand Catalytic System
Hu, Qi-Qi,Gao, Yan-Ting,Sun, Jia-Chen,Gao, Jing-Jing,Mu, Hong-Xiao,Li, Yi-Ming,Zheng, Ya-Nan,Yang, Kai-Rui,Zhu, Yan-Ping
supporting information, p. 9000 - 9005 (2021/11/24)
An efficient iodine-imine synergistic promoted Povarov-type multicomponent reaction was reported for the synthesis of a practical 2,2′-biquinoline scaffold. The tandem annulation has reconciled iodination, Kornblum oxidation, and Povarov aromatization, where the methyl group of the methyl azaarenes represents uniquely reactive input in the Povarov reaction. This method has broad substrate scope and mild conditions. Furthermore, these 2,2′-biquinoline derivatives had been directly used as bidentate ligands in metal-catalyzed reactions.
Facile synthesis of 1,3,4-oxadiazoles via iodine promoted oxidative annulation of methyl-azaheteroarenes and hydrazides
Shang, Zhi-Hao,Sun, Ji-Na,Guo, Jiang-Shan,Sun, Yuan-Yuan,Weng, Wei-Zhao,Zhang, Zhen-Xiao,Li, Zeng-Jing,Zhu, Yan-Ping
supporting information, (2020/01/08)
An oxidative sp3 C–H bond of methyl-azaheteroarenes protocol was reported for the synthesis of 1,3,4-oxadiazoles via [4 + 1] annulation with hydrazides. This protocol enables 1,3,4-oxadiazole and quinoline linked diheterocycles via selective oxidation of sp3 C–H bond of methyl-azaheteroarenes in the presence of I2-DMSO. The reaction has a broad substrate scope and good functional group tolerance for methyl-azaheteroarenes and hydrazides.
