- Additive-freeN-methylation of amines with methanol over supported iridium catalyst
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An efficient and versatile zinc oxide-supported iridium (Ir/ZnO) catalyst was developed to catalyze the additive-freeN-methylation of amines with methanol. Mechanistic studies suggested that the high catalytic reactivity is rooted in the small sizes (1.4 nm) of Ir nanoparticles and the high ratio (93%) of oxidized iridium species (IrOx, Ir3+and Ir4+) on the catalyst. Moreover, the delicate cooperation between the IrOxand ZnO support also promoted its high reactivity. The selectivity of this catalyticN-methylation was controllable between dimethylation and monomethylation by carefully tuning the catalyst loading and reaction solvent. Specifically, neat methanol with high catalyst loading (2 mol% Ir) favored the formation ofN,N-dimethylated amine, while the mesitylene/methanol mixture with low catalyst loading (0.5 mol% Ir) was prone to producing mono-N-methylated amines. An environmentally benign continuous flow system with a recycled mode was also developed for the efficient production ofN-methylated amines. With optimal flow rates and amine concentrations, a variety ofN-methylamines were produced with good to excellent yields in this Ir/ZnO-based flow system, providing a starting point for the clean and efficient production ofN-methylamines with this cost-effective chemical process.
- Liu, Xiang,Loh, Teck-Peng,Qiang, Wenwen,Wang, Jing,Ye, Sen,Zhu, Longfei
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p. 3364 - 3375
(2021/06/06)
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- Photorearrangement of Quinoline-Protected Dialkylanilines and the Photorelease of Aniline-Containing Biological Effectors
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The direct release of dialkylanilines was achieved by controlling the outcome of a photorearrangement reaction promoted by the (8-cyano-7-hydroxyquinolin-2-yl)methyl (CyHQ) photoremovable protecting group. The substrate scope was investigated to obtain structure-activity relationships and to propose a reaction mechanism. Introducing a methyl substituent at the 2-methyl position of the CyHQ core enabled the bypass of the photorearrangement and significantly improved the aniline release efficiency. We successfully applied the strategy to the photoactivation of mifepristone (RU-486), an antiprogestin drug that is also used to induce the LexPR gene expression system in zebrafish and the gene-switch regulatory system based on the pGL-VP chimeric regulator in mammals.
- Deodato, Davide,Asad, Naeem,Dore, Timothy M.
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p. 7342 - 7353
(2019/06/08)
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- Diverse catalytic reactivity of a dearomatized PN3P?-nickel hydride pincer complex towards CO2 reduction
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A dearomatized PN3P?-nickel hydride complex has been prepared using an oxidative addition process. The first nickel-catalyzed hydrosilylation of CO2 to methanol has been achieved, with unprecedented turnover numbers. Selective methylation and formylation of amines with CO2 were demonstrated by such a PN3P?-nickel hydride complex, highlighting its versatile functions in CO2 reduction.
- Li, Huaifeng,Gon?alves, Théo P.,Zhao, Qianyi,Gong, Dirong,Lai, Zhiping,Wang, Zhixiang,Zheng, Junrong,Huang, Kuo-Wei
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supporting information
p. 11395 - 11398
(2018/10/20)
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- N, N -Dimethylation of nitrobenzenes with CO2 and water by electrocatalysis
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We have proposed a strategy for the synthesis of N,N-dimethylanilines from nitrobenzene and its derivatives, CO2, and water via an electrochemical reaction under ambient conditions. H+ generated from H2O was used as the hydrogen source. Pd/Co-N/carbon, in which the Pd nanoparticles were supported on Co-N/carbon, was designed and used as the electrocatalyst. It was found that the electrocatalyst was very efficient for the reaction in MeCN solution with 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Bmim]Tf2N) as the supporting electrolyte and 1-amino-methylphosphonic acid (AMPA) as the thermal co-catalyst. A series of control experiments showed that Pd/Co-N/carbon and AMPA cooperated very well in accelerating the reaction. This synthetic route has some obvious advantages, such as using CO2 and water as the reactants, ambient reaction conditions, and high yields of the desired products. This opens up a way to synthesize chemicals by the combination of an electrocatalyst and a thermal catalyst with organic compounds, CO2, and water as the reactants.
- Sun, Xiaofu,Zhu, Qinggong,Hu, Jiayin,Kang, Xinchen,Ma, Jun,Liu, Huizhen,Han, Buxing
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p. 5669 - 5674
(2017/08/01)
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- Reductive Umpolung of Carbonyl Derivatives with Visible-Light Photoredox Catalysis: Direct Access to Vicinal Diamines and Amino Alcohols via α-Amino Radicals and Ketyl Radicals
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Visible-light-mediated photoredox-catalyzed aldimine-aniline and aldehyde-aniline couplings have been realized. The reductive single electron transfer (SET) umpolung of various carbonyl derivatives enabled the generation of intermediary ketyl and α-amino radical anions, which were utilized for the synthesis of unsymmetrically substituted 1,2-diamines and amino alcohols. Anilines can be coupled with aldimines or aldehydes in a visible-light-mediated photoredox-catalyzed process. Reductive single electron transfer (SET) umpolung of the carbonyl derivatives leads to the generation of intermediary ketyl and α-amino radical anions, which were used for the synthesis of unsymmetrically substituted 1,2-diamines and amino alcohols.
- Fava, Eleonora,Millet, Anthony,Nakajima, Masaki,Loescher, Sebastian,Rueping, Magnus
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supporting information
p. 6776 - 6779
(2016/06/09)
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- New deoxygenation method for amine n-oxides using dimethylthiocarbamoyl chloride
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A facile and efficient deoxygenation method for various amine N-oxides to their corresponding amines is described. The experimental procedure is quite simple and the products are obtained in excellent yields. Copyright Taylor & Francis Group, LLC.
- Caliskan, Hafize,Zaim, Oemer
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experimental part
p. 3078 - 3083
(2010/11/04)
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- Naphthalene-1,8-diylbis(diphenylmethylium) as an organic two-electron oxidant: Benzidine synthesis via oxidative self-coupling of N,N-dialkylanilines
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Naphthalene-1,8-diylbis(diphenylmethylium) exhibits a unique electron-transfer reduction behavior due to the close proximity of the two triarylmethyl cations, which form a C-C bond while accepting two electrons, leading to 1,1,2,2-tetraphenylacenaphthene. The preparation of the dication was readily accomplished under anhydrous conditions starting from a cyclic bis(triarylmethyl) ether, derived from 1,8-dibromonaphthalene. The process proceeded via deoxygenation accompanying the formation of a disiloxane on treatment with a silylating agent (Me3SiClO4 or Me 3SiOTf) in 1,1,1,3,3,3-hexafluoropropan-2-ol. The dication was successfully employed for oxidative coupling of N,N-dialkylanilines at the paraposition to afford the corresponding benzidines in good to excellent yield.
- Saitoh, Terunobu,Yoshida, Suguru,Ichikawa, Junji
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p. 6414 - 6419
(2007/10/03)
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- 1,8-Bis(diphenylmethylium)naphthalenediyl dication as an organic oxidant: Synthesis of benzidines via self-coupling of N,N-Dialkylanilines
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(Chemical equation presented) 1,8-Bis(diphenylmethylium)naphthalenediyl dications promoted oxidative coupling of various N,N-dialkylanilines to afford the corresponding para-coupled bisanilines, benzidines, in good to excellent yield. The dications were readily prepared from a cyclic ether precursor, derived from 1,8-dibromonaphthalene, via deoxygenation with a silylating reagent in 1,1,1,3,3,3-hexafluoro-2-propanol under anhydrous conditions.
- Saitoh, Terunobu,Yoshida, Suguru,Ichikawa, Junji
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p. 4563 - 4565
(2007/10/03)
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- SYNTHESE DE N,N-DIALKYL-3,5-DIALKYL-ANILINES A PARTIR DES SELS DE TRIALKYL-2,4,6-PYRYLIUM
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We have optimized through an experimental design the synthesis of N,N-diethyl-3,5-dimethylaniline from 2,4,6-trimethylpyrylium terafluoroborate (I) and diethylamine in a new reaction medium (acetonitrile/triethylamine).Optimal conditions have been applied with high yields to the synthesis of various 3,5-dimethylanilines derived from I and dimethylamine, morpholine, N-methylpiperazine, piperazine, dihexylamine, piperidine, and pyrrolidine respectively. 2-Alkyl-4,6-dimethylpyrylium tetrafluoroborates react regioselectively with diethylamine to afford N,N-diethyl-3-alkyl-5-methyl anilines under these conditions.
- Vernaudon, Pascal,Rajoharison, Harivelo G.,Roussel, Chritian
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p. 205 - 211
(2007/10/02)
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- Substituted N,N-Dialkylanilines: Relative Ionization Energies and Proton Affinities through Determination of Ion-Molecule Reaction Equilibrium Constants
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The relative ionization energies and proton affinities of N,N-dimethyl-, N,N-diethyl-, and N,N-di-n-propylaniline, and meta- and para-methyl-substituted analogues (as well as N,N,3,5-tetramethylaniline and 4-chloro-N,N-diethylaniline) have been determined in the gas phase through measurements of the equilibrium constants of charge-transfer and proton-transfer reactions in an ion cyclotron resonance spectrometer.Absolute values are assigned to the ionization energies and proton affinities generated in these experiments.Comparison atandards were the ionization potential (7.12 eV) and proton affinity (223.4 kcal/mol) for N,N-dimethylaniline taken from the literature.The heats of formation of the parent radical cations, M+, and the corresponding protonated molecules, MH+, vary in the same way, differing from one another by 21 +/- 2 kcal/mol over the entire set; that is, the radical cations of these compounds display a constant hydrogen affinity of 74 +/- 2 kcal/mol.This is interpreted to mean that all the compounds protonate at the nitrogen atom; previous work had suggested that meta-substituted isomers protonate on the ring.Further, it is demonstrated that variations in both the ionization energy and the proton affinity values upon changes in ring substitution can be predicted from the appropriate Hammett ? values, but not from the corresponding ?+ values; changes brought about by differing N-substituents correlate with ?* values.
- Lias, Sharon G.,Jackson, Jo-Anne A.,Argentar, Harold,Liebman, Joel F.
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p. 333 - 338
(2007/10/02)
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