10075-50-0Relevant articles and documents
Chemoselective deprotection of allylic amines catalyzed by Grubbs' carbene
Alcaide, Benito,Almendros, Pedro,Alonso, Jose M.,Luna, Amparo
, p. 668 - 672 (2005)
A commercially available ruthenium complex (first generation Grubbs' carbene) was used for the catalytic deprotection of allylic amines (secondary as well as tertiary), by using for the first time reagents different from palladium catalysts. Interestingly, the catalytic system directs the reaction toward the selective deprotection of allylamines in the presence of allylic ethers.
Ga(DS)3-catalysed double hydroarylation of acetylenic esters with indoles for the synthesis of bisindolyl propanoates
An, Li-Tao,Cai, Jing-Jing,Pan, Xiang-Qiang,Chen, Tang-Ming,Zou, Jian-Ping,Zhang, Wei
, p. 3996 - 3998 (2015)
Abstract An efficient synthetic method for bisindolyl propanoates has been developed. Ga(DS)3-catalysed double hydroarylation of acetylenic esters with indoles in water afforded regioselective products with up to 99% yield.
CO2-Catalyzed Efficient Dehydrogenation of Amines with Detailed Mechanistic and Kinetic Studies
Riemer, Daniel,Schilling, Waldemar,Goetz, Anne,Zhang, Yu,Gehrke, Sascha,Tkach, Igor,Hollóczki, Oldamur,Das, Shoubhik
, p. 11679 - 11687 (2018)
CO2-catalyzed dehydrogenation of amines has been achieved under photocatalytic conditions. With this concept, various amines have been selectively dehydrogenated to the corresponding imines in the presence of different functional groups such as nitrile, nitro, ester, halogen, ether, thioether, and carbonyl or carboxylic acid moieties. At the end, the CO2-catalyzed synthesis of pharmaceutical drugs has been achieved. The CO2 radical has been detected by EPR spectroscopy using DMPO, and the mechanism of this reaction is proposed on the basis of DFT calculations and experimental evidence.
Novel Arylindigoids by Late-Stage Derivatization of Biocatalytically Synthesized Dibromoindigo
Schnepel, Christian,Dodero, Veronica I.,Sewald, Norbert
, p. 5404 - 5411 (2021)
Indigoids represent natural product-based compounds applicable as organic semiconductors and photoresponsive materials. Yet modified indigo derivatives are difficult to access by chemical synthesis. A biocatalytic approach applying several consecutive selective C?H functionalizations was developed that selectively provides access to various indigoids: Enzymatic halogenation of l-tryptophan followed by indole generation with tryptophanase yields 5-, 6- and 7-bromoindoles. Subsequent hydroxylation using a flavin monooxygenase furnishes dibromoindigo that is derivatized by acylation. This four-step one-pot cascade gives dibromoindigo in good isolated yields. Moreover, the halogen substituent allows for late-stage diversification by cross-coupling directly performed in the crude mixture, thus enabling synthesis of a small set of 6,6’-diarylindigo derivatives. This chemoenzymatic approach provides a modular platform towards novel indigoids with attractive spectral properties.
Hydrophobic Metal Halide Perovskites for Visible-Light Photoredox C?C Bond Cleavage and Dehydrogenation Catalysis
Hong, Zonghan,Chong, Wee Kiang,Ng, Andrew Yun Ru,Li, Mingjie,Ganguly, Rakesh,Sum, Tze Chien,Soo, Han Sen
, p. 3456 - 3460 (2019)
Two-dimensional lead and tin halide perovskites were prepared by intercalating the long alkyl group 1-hexadecylammonium (HDA) between the inorganic layers. We observed visible-light absorption, narrow-band photoluminescence, and nanosecond photoexcited lifetimes in these perovskites. Owing to their hydrophobicity and stability even in humid air, we applied these perovskites in the decarboxylation and dehydrogenation of indoline-2-carboxylic acids. (HDA)2PbI4 or (HDA)2SnI4 were investigated as photoredox catalysts for these reactions, and quantitative conversion and high yields were observed with the former.
DMSO/t-BuONa/O2-Mediated Aerobic Dehydrogenation of Saturated N-Heterocycles
Cai, Hu,Tan, Wei,Xie, Yongfa,Yang, Ruchun,Yue, Shusheng
, p. 7501 - 7509 (2020)
Aromatic N-heterocycles such as quinolines, isoquinolines, and indolines are synthesized via sodium tert-butoxide-promoted oxidative dehydrogenation of the saturated heterocycles in DMSO solution. This reaction proceeds under mild reaction conditions and has a good functional group tolerance. Mechanistic studies suggest a radical pathway involving hydrogen abstraction of dimsyl radicals from the N-H bond or α-C-H of the substrates and subsequent oxidation of the nitrogen or α-aminoalkyl radicals.
A new and efficient one-pot synthesis of indoles
Bratulescu, George
, p. 984 - 986 (2008)
The synthesis of indoles is accomplished in high yields from phenylhydrazines and pyruvic acid using microwave irradiation.
Aerobic oxidative dehydrogenation of N-heterocycles over OMS-2-based nanocomposite catalysts: Preparation, characterization and kinetic study
Bi, Xiuru,Tang, Tao,Meng, Xu,Gou, Mingxia,Liu, Xiang,Zhao, Peiqing
, p. 360 - 371 (2020)
OMS-2-based nanocomposites doped with tungsten were prepared for the first time and their remarkably enhanced catalytic activity and recyclability in aerobic oxidative dehydrogenation of N-heterocycles were examined in detail. Many tetrahydroquinoline derivatives and a broad range of other N-heterocycles could be tolerated by the catalytic system using a biomass-derived solvent as a reaction medium. Newly generated mixed crystal phases, noticeably enhanced surface areas and labile lattice oxygen of the OMS-2-based nanocomposite catalysts might contribute to their excellent catalytic performance. Moreover, a kinetic study was extensively performed which concluded that the dehydrogenation of 1,2,3,4-tetrahydroquinoline is a first-order reaction, and the apparent activation energy is 29.66 kJ mol-1
Dehydrogenation of indoline by cytochrome P450 enzymes: A novel "aromatase" process
Sun, Hao,Ehlhardt, William J.,Kulanthaivel, Palaniappan,Lanza, Diane L.,Reilly, Christopher A.,Yost, Garold S.
, p. 843 - 851 (2007)
Indoline derivatives possess therapeutic potential within a variety of drug candidates. In this study, we found that indoline is aromatized by cytochrome P450 (P450) enzymes to produce indole through a novel dehydrogenation pathway. The indole products can potentially be bioactivated to toxic intermediates through an additional dehydrogenation step. For example, 3-substituted indoles like 3-methylindole and zafirlukast [4-(5-cyclopentyloxy-carbonylamino-1-methyl- indol-3-ylmethyl)-3-methoxy-N-o-tolylsulfonylbenzamide] are dehydrogenated to form 3-methyleneindolenine electrophiles, which react with protein and/or DNA nucleophilic residues to cause toxicities. Another potentially significant therapeutic consequence of indoline aromatization is that the product indoles might have dramatically different therapeutic potency than the parent indolines. In this study, indoline was indeed efficiently aromatized by human liver microsomes and by several P450s, but not by flavin-containing monooxygenase (FMO) 3. CYP3A4 had the highest aromatase activity. Four additional indoline metabolites [2,3,4,7-tetrahydro-4,5-epoxy-1H-indole (M1); N-hydroxyindole (M2), N-hydroxyindoline (M3), and M4 ([1,4,2,5]dioxadiazino[2,3-a:5,6-a′] diindole)] were characterized; none was a metabolite of indole. M1 was an arene oxide from P450 oxidation, and M2, M3, and M4 were produced by FMO3. Our data indicated that indoline was oxidized to M3 and then to an intermediate indoline nitrone, which tautomerized to form M2, and subsequently dimerized to a di-indoline. This dimer was immediately oxidized by FMO3 or atmospheric oxygen to the final product, M4. No evidence was found for the P450-mediated production of an aliphatic alcohol from indoline that might dehydrate to produce indole. Therefore, P450 enzymes catalyze the novel "aromatase" metabolism of indoline to produce indole. The aromatase mechanism does not seem to occur through N-oxidation or dehydration of an alcohol but rather through a formal dehydrogenation pathway. Copyright
Two-Dimensional Metal-Organic Layers for Electrochemical Acceptorless Dehydrogenation of N-Heterocycles
Yang, Ling,Ma, Fa-Xue,Xu, Fan,Li, Dong,Su, Liangmei,Xu, Hai-Chao,Wang, Cheng
, p. 3557 - 3560 (2019)
The catalytic acceptorless dehydrogenation (CAD) is an attractive synthetic route to unsaturated compounds because of its high atomic efficiency. Here we report electrochemical acceptorless dehydrogenation of N-heterocycles to obtain quinoline or indole derivatives using metal-organic layer (MOL) catalyst. MOL is the two-dimensional version of metal-organic frameworks (MOF), and it can be constructed on conductive multi-walled carbon nanotubes via facile solvothermal synthesis to overcome the conductivity constraint for MOFs in electrocatalysis. TEMPO-OPO3 2? was incorporated into the system through a ligand exchange with capping formate on the MOL surface to serve as the active catalytic centers. The hybrid catalyst is efficient in the organic conversion and can be readily recycled and reused.
