- Broadening the Horizon of the Bell–Evans–Polanyi Principle towards Optically Triggered Structure Planarization
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Finding a relationship between kinetics and thermodynamics may be difficult. However, semi-empirical rules exist to compensate for this shortcoming, among which the Bell–Evans–Polanyi (B-E-P) principle is an example for reactions involving bond breakage a
- Chen, Yi,Chang, Kai-Hsin,Meng, Fan-Yi,Tseng, Sheng-Ming,Chou, Pi-Tai
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- Mild Radical Oxidative sp3-Carbon-Hydrogen Functionalization: Innovative Construction of Isoxazoline and Dibenz[ b, f ]oxepine/azepine Derivatives
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Direct carbon-hydrogen bond functionalization has emerged as a powerful synthetic method for the straightforward and modular functionalization of organic molecules. In this account, we described our latest contributions in the area of oxidative sp3-carbon-hydrogen bond functionalization using mild radical oxidants for the construction of structurally important heterocycles. We have developed two new methodologies in which a new class of substrate and an uncommon nucleophilic reagent have been introduced to the existing palette of reaction partners for oxidative carbon-hydrogen functionalization. To achieve these results, the 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) radical and a benzoyl peroxide/copper(I) system have been employed as oxidants for the dehydrogenative one-pot synthesis of N-alkoxycarbonyl-protected isoxazolines from hydroxylamines and for the synthesis of dibenz[b,f]oxepines, dibenzo[b,f]thiepines, and dibenz[b,f]azepines from simple xanthenes, thioxanthenes, and acridanes, respectively. 1 Introduction 2 2,2,6,6-Tetramethylpiperidinyloxyl-Mediated Dehydrogenative Formation and Trapping of Unstable Nitrones: Synthesis of N-Alkoxycarbonyl-Protected Isoxazoline Derivatives 3 Oxidative sp3-Carbon-Hydrogen Bond Functionalization and Ring Expansion with Trimethylsilyldiazomethane: Synthesis of Dibenzoxepines, Dibenzothiepines, and Dibenzazepines 4 Conclusions and Outlook.
- Gini, Andrea,Manche?o, Olga García
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- Azepine- or Azocine-Embedded Hexabenzocoronene Derivatives as Nitrogen-Doped Saddle or Saddle-Helix Nanographenes
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Two novel nitrogen-doped, hexa-peri-hexabenzocoronene (HBC)-based nanographenes (NGs) 1 and 2 bearing an azepine and an azocine at the fjord region, respectively, were synthesized and characterized. Notably, structure 1 was synthesized by Diels–Alder reac
- An, Peng,He, Run-Ying,Li, Ranran,Ma, Bin,Xiao, Ming-Jun,Zhang, Bin,Zhang, Yi-Kang
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supporting information
p. 24478 - 24483
(2021/10/19)
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- Intermediate compound, carbamazepine and derivative thereof as well as preparation method of oxcarbazepine and derivative thereof
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The invention provides an intermediate compound, carbamazepine and a derivative thereof as well as a preparation method of oxcarbazepine and a derivative thereof. 2-substituted aminophenylacetate or 2-substituted aminophenylacetonitrile and 2-halobenzonitrile are used as raw materials, substitution reaction, intramolecular condensation reaction, hydrolysis and hydrochloric acid acidification are carried out to obtain the oxcarbazepine and the derivative 5-substituent-10-oxa-10, 11-dihydro-5H-dibenzo [b, f] aza thereof, and the derivative of the oxcarbazepine can be used as a raw material to prepare the carbamazepine and the derivative 5-substituted iminostilbene thereof, an intermediate compound iminostilbene and intermediate compounds 5-substituted-10-methoxyiminostilbene and 10-methoxyiminostilbene. The raw materials used in the method are cheap and easy to obtain, and the cost is low; the preparation method is simple, conditions are easy to realize, the method is simple, convenientand safe to operate, and the process flow is short; the production amount of three wastes is small, and thus, the method is environmentally friendly; and a target product has high yield and purity, and is suitable for industrial production.
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- Preparation method of N-methylamine compound
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The invention discloses a preparation method of a N-methylamine compound. The preparation method comprises the following steps: under an inertia organic solvent or solvent-free condition and under a support-type nano-sized gold catalyst effect, a primary amine compound or a secondary amine compound is subjected to a N-methylation reaction with carbon dioxide and hydrogen to obtain the product. The preparation method takes CO2 as a methyl source, takes hydrogen as a reducing agent, and takes the support-type nano-gold as a catalyst, and has the advantages that process is simple, catalyst activity is high, reaction rate is fast, the catalyst recovery and utilization are convenient, the application scope of a substrate is wide, the production cost is low, the benifit is high, the post-treatment is simple, repeatability is good, safe performance is high, and environmental protection is achieved, and the method is adapted to industrial production.
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Paragraph 0094; 0095; 0096; 0099
(2017/08/19)
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- Direct Methylation of Amines with Carbon Dioxide and Molecular Hydrogen using Supported Gold Catalysts
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The N-methylation of amines with CO2 and H2 is an important step in the synthesis of bioactive compounds and chemical intermediates. The first heterogeneous Au catalyst is reported for this methylation reaction with good to excellent yields. The average turnover frequency (TOF) based on surface Au atoms is 45 h-1, which is the highest TOF value ever reported for the methylation of aniline with CO2 and H2. Furthermore, the catalyst is tolerant toward a variety of amines, which includes aromatic, aliphatic, secondary, and primary amines. Preliminary mechanistic studies suggest that the N-alkyl formamide might be an intermediate in the N-methylation of amine process. Moreover, through a one-pot process, it is possible to convert primary amines, aldehydes, and CO2 into unsymmetrical tertiary amines with H2 as a reductant in the presence of the Au catalyst.
- Du, Xian-Long,Tang, Gao,Bao, Hong-Liang,Jiang, Zheng,Zhong, Xin-Hua,Su, Dang Sheng,Wang, Jian-Qiang
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p. 3489 - 3496
(2015/11/02)
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- Oxidative C-H bond functionalization and ring expansion with TMSCHN2: A copper(I)-catalyzed approach to dibenzoxepines and dibenzoazepines
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Tricyclic dibenzoxepines and dibenzazepines are important therapeutic agents for the pharmaceutical industry and academic research. However, their syntheses are generally rather tedious, requiring several steps that involve a Wagner-Meerwein-type rearrangement under harsh conditions. Herein, we present the first copper(I)-catalyzed oxidative C-H bond functionalization and ring expansion with TMSCHN2 to yield these important derivatives in a facile and straightforward way. Cut a long story short: Tricyclic dibenzoxepines and dibenzazepines are important therapeutic agents for pharmaceuticals, but their syntheses are generally rather tedious. A copper(I)-catalyzed oxidative C-H bond functionalization and ring expansion sequence with TMSCHN2 has been developed to yield these important derivatives in a facile and straightforward way.
- Stopka, Tobias,Marzo, Leyre,Zurro, Mercedes,Janich, Simon,Würthwein, Ernst-Ulrich,Daniliuc, Constantin G.,Alemán, José,Manche?o, Olga García
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p. 5049 - 5053
(2015/04/27)
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- Synthesis of dibenzoheteropines of group 13-16 elements via ring-closing metathesis
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The ring-closing metathesis (RCM) of bis(2-vinylphenyl)silanes in the presence of the second-generation Hoveyda-Grubbs catalyst in toluene at 100 C afforded dibenzo[b,f]silepines in excellent yields. Other dibenzoheteropines of group 13-16 elements were also prepared via the RCM of the corresponding heteroatom-tethered dienes.
- Matsuda, Takanori,Sato, Shinya
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p. 3329 - 3335
(2013/06/26)
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- Substituent-Dependent Reactivity in the Photodimerization of N-Substituted Dibenz[b,f]azepines
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The photoprocesses of a series of N-substituted dibenz[b,f]azepines (iminostilbenes) were studied by absorption and emission spectroscopy, by laser flash photolysis, and by preparative irradiation with NMR analysis. In solutions, 2π+2π photodimers of N-cyano and N-acyl dibenzazepines are formed via the triplet state upon acetone- or benzophenone-sensitized energy transfer. T-T absorption spectra were measured and absorption coefficients were determined. The triplet energy transfer is equally efficient for N-alkyl dibenzazepines, which do not dimerize. Excited states of nπ* character in the latter cases are discussed to rationalize the different reactivities. In spite of negligible intersystem crossing of 21 dibenzazepine derivatives, photodimers of N-acyl and N-cyano dibenzazepines are formed upon direct excitation in concentrated solutions (0.01-0.1 moldm-3) as well as in the solid state. A selective anti-configuration of the photodimers was found throughout.
- Querner, Jens,Wolff, Thomas,Goerner, Helmut
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p. 283 - 293
(2007/10/03)
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- A Free Radical Route to the Benzazepines and Dibenzazepines
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Free radical ring expansion of six membered azocycles provides a new entry to the preparation of benzazepines and dibenzazepines.
- Zheng, Zhizhen Barbara,Dowd, Paul
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p. 7709 - 7712
(2007/10/02)
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