2412-58-0Relevant academic research and scientific papers
Rh/TiO2-Photocatalyzed Acceptorless Dehydrogenation of N-Heterocycles upon Visible-Light Illumination
Bahnemann, Detlef W.,Balayeva, Narmina O.,Dillert, Ralf,Mamiyev, Zamin,Zheng, Nan
, p. 5542 - 5553 (2020/08/25)
TiO2 is an effective and extensively employed photocatalyst, but its practical use in visible-light-mediated organic synthesis is mainly hindered by its wide band gap energy. Herein, we have discovered that Rh-photodeposited TiO2 nanoparticles selectively dehydrogenate N-heterocyclic amines with the concomitant generation of molecular hydrogen gas in an inert atmosphere under visible light (λmax = 453 nm) illumination at room temperature. Initially, a visible-light-sensitive surface complex is formed between the N-heterocycle and TiO2. The acceptorless dehydrogenation of N-heterocycles is initiated by direct electron transfer from the HOMO energy level of the amine via the conduction band of TiO2 to the Rh nanoparticle. The reaction condition was optimized by examining different photodeposited noble metals on the surface of TiO2 and solvents, finding that Rh0 is the most efficient cocatalyst, and 2-propanol is the optimal solvent. Structurally diverse N-heterocycles such as tetrahydroquinolines, tetrahydroisoquinolines, indolines, and others bearing electron-deficient as well as electron-rich substituents underwent the dehydrogenation in good to excellent yields. The amount of released hydrogen gas evinces that only the N-heterocyclic amines are oxidized rather than the dispersant. This developed method demonstrates how UV-active TiO2 can be employed in visible-light-induced synthetic dehydrogenation of amines and simultaneous hydrogen storage applications.
A Visible-Light Promoted Amine Oxidation Catalyzed by a Cp*Ir Complex
Davis, Holly Jane,H?ussinger, Daniel,Ward, Thomas R.,Okamoto, Yasunori
, p. 4512 - 4516 (2020/07/27)
Through a rapid screening of Cp*Ir complexes based on a turn-on type fluorescence readout, a [Cp*Ir(dipyrido[3,2-a : 2’,3’-c]phenazine)Cl]+ complex was found to catalyze the blue-light promoted dehydrogenation of N-heterocycles under physiological conditions. In the dehydrogenation of tetrahydroisoquinolines, the catalyst preferentially yielded the monodehydrogenated product, accompanying H2O2 generation. We surmise that this mechanism may be reminiscent of flavin-dependent oxidases.
Dehydrogenation of Nitrogen Heterocycles Using Graphene Oxide as a Versatile Metal-Free Catalyst under Air
Zhang, Jingyu,Chen, Shiya,Chen, Fangfang,Xu, Wensheng,Deng, Guo-Jun,Gong, Hang
supporting information, p. 2358 - 2363 (2017/07/22)
Graphene oxide (GO) has been developed as an inexpensive, environmental friendly, metal-free carbocatalyst for the dehydrogenation of nitrogen heterocycles. Valuable compounds, such as quinoline, 3,4-dihydroisoquinoline, quinazoline, and indole derivatives, have been successfully used as substrates. The investigation of various oxygen-containing molecules with different conjugated systems indicated that both the oxygen-containing groups and large π-conjugated system in GO sheets are essential for this reaction. (Figure presented.).
Acceptorless dehydrogenation of nitrogen heterocycles with a versatile iridium catalyst
Wu, Jianjun,Talwar, Dinesh,Johnston, Steven,Yan, Ming,Xiao, Jianliang
supporting information, p. 6983 - 6987 (2013/07/26)
Gas up: A cyclometalated iridium complex is found to catalyze the dehydrogenation of various benzofused N-heterocycles, thus releasing H 2. Driven by as low as 0.1 mol % catalyst, the reaction affords quinolines, indoles, quinoxalines, isoquinolines, and β-carbolines in high yields. Copyright
Substituted 2-[monoannelated (3,4-,4,5-, and 5,6-) pyridylalkylenesulfinyl]benzimidazoles
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, (2008/06/13)
The present invention provides novel substituted 2-[monoannelated(3,4- 4,5-, and 5,6-)pyridylalkylenesulfinyl]-benzimidazoles with gastric acid inhibiting effects.
