- Minimization of Back-Electron Transfer Enables the Elusive sp3 C?H Functionalization of Secondary Anilines
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Anilines are some of the most used class of substrates for application in photoinduced electron transfer. N,N-Dialkyl-derivatives enable radical generation α to the N-atom by oxidation followed by deprotonation. This approach is however elusive to monosubstituted anilines owing to fast back-electron transfer (BET). Here we demonstrate that BET can be minimised by using photoredox catalysis in the presence of an exogenous alkylamine. This approach synergistically aids aniline SET oxidation and then accelerates the following deprotonation. In this way, the generation of α-anilinoalkyl radicals is now possible and these species can be used in a general sense to achieve divergent sp3 C?H functionalization.
- Zhao, Huaibo,Leonori, Daniele
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supporting information
p. 7669 - 7674
(2021/03/08)
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- Cyclic (Alkyl)(amino)carbene Ligand-Promoted Nitro Deoxygenative Hydroboration with Chromium Catalysis: Scope, Mechanism, and Applications
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Transition metal catalysis that utilizes N-heterocyclic carbenes as noninnocent ligands in promoting transformations has not been well studied. We report here a cyclic (alkyl)(amino)carbene (CAAC) ligand-promoted nitro deoxygenative hydroboration with cost-effective chromium catalysis. Using 1 mol % of CAAC-Cr precatalyst, the addition of HBpin to nitro scaffolds leads to deoxygenation, allowing for the retention of various reducible functionalities and the compatibility of sensitive groups toward hydroboration, thereby providing a mild, chemoselective, and facile strategy to form anilines, as well as heteroaryl and aliphatic amine derivatives, with broad scope and particularly high turnover numbers (up to 1.8 × 106). Mechanistic studies, based on theoretical calculations, indicate that the CAAC ligand plays an important role in promoting polarity reversal of hydride of HBpin; it serves as an H-shuttle to facilitate deoxygenative hydroboration. The preparation of several commercially available pharmaceuticals by means of this strategy highlights its potential application in medicinal chemistry.
- Zhao, Lixing,Hu, Chenyang,Cong, Xuefeng,Deng, Gongda,Liu, Liu Leo,Luo, Meiming,Zeng, Xiaoming
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supporting information
p. 1618 - 1629
(2021/01/25)
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- Preparation method of 4- polyfluoro methoxy O-phenylenediamine (by machine translation)
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The method disclosed by the invention 4 - is characterized in that the aminophenol, and the alkali :(1) are reacted at a mole ratio of the 1:0.8-1.5, 20-40 °C compound 0.1-24h with the halogen, and, the halogen compound in the solvent to 1:1.0-3.0,20-120 °C, 0.01-20Mpa react with 1-72h. 1-72h the 4 - 1:0.8-30.0 ammonia solution ;(2)4 - or the halogen compound at a mole ratio of the compound of the 1:0.2 - 2.5 amino phenol, 30-80 °C with 0.1-24h;(3)4 - the halogen and the halogen compound in the solvent 0.1-10%, 50-200 °C, 0.01-10Mpa: 4 . (by machine translation)
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Paragraph 0007
(2020/01/03)
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- Catalytic Transfer Hydrodebenzylation with Low Palladium Loading
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A highly-efficient catalytic system for hydrodebenzylation reaction is described. The cleavage of O-benzyl and N-benzyl protecting groups was performed using an uncommonly low palladium loading (0.02–0.3 mol%; TON up to 5000) in a relatively short reaction time. The approach was used for a variety of substrates including pharmaceutically important precursors, and gram-scale deprotection reaction was shown. Transfer conditions together with easy-to-make Pd/C catalyst are the key features of this debenzylation scheme. (Figure presented.).
- Yakukhnov, Sergey A.,Ananikov, Valentine P.
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p. 4781 - 4789
(2019/09/16)
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- Method for synthesizing insecticide metaflumizone intermediate p-trifluoromethoxy aniline
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The invention discloses a method for synthesizing an insecticide metaflumizone intermediate, namely p-trifluoromethoxy aniline and belongs to the field of insecticide preparation. The method is characterized in that the p-trifluoromethoxy aniline is prepared from p-trifluoromethoxy benzene and sodium amide under the action of an auxiliary reaction mixture. The method comprises the following reaction steps: 1) in the presence of a protection gas and under an intense stirring condition, putting trifluoromethoxy benzene, the auxiliary reaction mixture and a solvent into a reaction kettle, heating to 80-95 DEG C, keeping for 2-4 hours, further adding sodium amide, heating to 135-155 DEG C, increasing the reaction pressure to 2-4 barometric pressure, and continuously reacting for 7-10 hours till completion; and 2) cooling the system, pouring into water of 5-8 times of the volume, extracting with a solvent B of 2-4 times of the volume of a reactant, washing an extraction liquid with water,drying with a drying agent, and concentrating, thereby obtaining p-trifluoromethoxy aniline. The method is simple in step, small in side reaction, high in yield, small in pollutant emission and safe to operate.
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Paragraph 0025-0049
(2019/01/23)
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- Method for continuous hydrogenation preparation of aromatic amine through nitro-compound
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The invention provides a method for continuous hydrogenation preparation of aromatic amine through a nitro-compound, and belongs to the field of heterogeneous catalysis. The method comprises the stepsthat the nitro-compound serves as a raw material, nano-porous palladium serves as a catalyst and hydrogen serves as a hydrogen source; a static bed liquid phase catalysis hydrogenation process is utilized for synthesizing the nitro-compound into the aromatic amine, and the activity of the catalyst is not lowered after 400-hour continuous running of the catalyst; continuous hydrogenation is carried out under the catalysis condition of the nano-porous palladium catalyst to obtain an aromatic amine product. The method is mild in reaction condition, high in reaction selectivity, compatible in substrate and good in stability, and industrial production is facilitated.
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Paragraph 0046-0047
(2019/06/27)
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- Visible-light-driven Efficient Photocatalytic Reduction of Organic Azides to Amines over CdS Sheet–rGO Nanocomposite
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CdS sheet–rGO nanocomposite as a heterogeneous photocatalyst enables visible-light-induced photocatalytic reduction of aromatic, heteroaromatic, aliphatic and sulfonyl azides to the corresponding amines using hydrazine hydrate as a reductant. The reaction shows excellent conversion and chemoselectivity towards the formation of the amine without self-photoactivated azo compounds. In the adopted strategy, CdS not only accelerates the formation of nitrene through photoactivation of azide but also enhances the decomposition of azide to a certain extent, which entirely suppressed formation of the azo compound. The developed CdS sheet-rGO nanocomposite catalyst is very active, providing excellent results under irradiation with a 40 W simple household CFL lamp.
- Singha, Krishnadipti,Mondal, Aniruddha,Ghosh, Subhash Chandra,Panda, Asit Baran
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p. 255 - 260
(2018/01/15)
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- AMINATION AND HYDROXYLATION OF ARYLMETAL COMPOUNDS
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In one aspect, the present disclosure provides methods of preparing a primary or secondary amine and hydroxylated aromatic compounds. In some embodiments, the aromatic compound may be unsubstituted, substituted, or contain one or more heteroatoms within the rings of the aromatic compound. The methods described herein may be carried out without the need for transition metal catalysts or harsh reaction conditions.
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Paragraph 0098; 0134; 0135; 0171
(2018/03/25)
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- Para-amino trifluoro-metoxybenzene solvent-free hydrogenation reduction process
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The invention relates to a para-amino trifluoro-metoxybenzene solvent-free hydrogenation reduction process and belongs to the field of pesticide chemical product preparation methods. The process mainly comprises the following steps: putting a raw material, namely para-nitro trifluoro-metoxybenzene, into a reduction reaction kettle; under conditions that no solvent is used and raney nickel is adopted as a catalyst, performing a hydrogenation reduction; after the reaction is completed, cooling, filtering and recycling the catalyst under normal pressure, and performing negative pressure distillation on filtrate, so as to obtain para-amino trifluoro-metoxybenzene. The whole process is carried out under a solvent-free process condition, so that emission of organic matters in the conventional production process can be reduced; the situation that carbaryl byproducts are generated through reactions of solvents such as methanol with reduced amino can be avoided, and the product purity can be improved; compared with a conventional solvent method, the process is relatively low in temperature, relatively low in energy consumption, low in production cost and beneficial to energy conservation and emission reduction.
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Paragraph 0011; 0020-0026
(2018/09/08)
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- Rapid heteroatom transfer to arylmetals utilizing multifunctional reagent scaffolds
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Arylmetals are highly valuable carbon nucleophiles that are readily and inexpensively prepared from aryl halides or arenes and widely used on both laboratory and industrial scales to react directly with a wide range of electrophiles. Although C-C bond formation has been a staple of organic synthesis, the direct transfer of primary amino (-NH2) and hydroxyl (-OH) groups to arylmetals in a scalable and environmentally friendly fashion remains a formidable synthetic challenge because of the absence of suitable heteroatom-transfer reagents. Here, we demonstrate the use of bench-stable N-H and N-alkyl oxaziridines derived from readily available terpenoid scaffolds as efficient multifunctional reagents for the direct primary amination and hydroxylation of structurally diverse aryl- and heteroarylmetals. This practical and scalable method provides one-step synthetic access to primary anilines and phenols at low temperature and avoids the use of transition-metal catalysts, ligands and additives, nitrogen-protecting groups, excess reagents and harsh workup conditions.
- Gao, Hongyin,Zhou, Zhe,Kwon, Doo-Hyun,Coombs, James,Jones, Steven,Behnke, Nicole Erin,Ess, Daniel H.,Kürti, László
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p. 681 - 688
(2017/06/30)
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- PROCESS FOR THE PREPARATION OF 4-SUBSTITUTED-1-(TRIFLUOROMETHOXY)BENZENE COMPOUNDS
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The present invention provides the process for the preparation of 4-substituted-1- (trifluoromethoxy) benzene compounds..
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- A normal pressure catalytic synthesis of aniline compounds and the use of catalyst (by machine translation)
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A normal pressure catalytic synthesis of aniline compounds is the nitrobenzene compound and solvent after mixing, adding catalyst to form suspension, then transfer to the with a quartz window in the high-pressure reactor, reactor for sealing and hydrogen purge after washing, maintaining a hydrogen under normal pressure conditions, under stirring condition, heating the reaction system to10-50oC, in strength is0.01-5W/cm2under the illumination of the reaction, the reaction time is 5 - 180min. This invention has mild condition, environmental protection, low cost, simple operation, reaction period is short, high product yield, selectivity is good. (by machine translation)
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Paragraph 0027-0030
(2017/04/14)
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- Pd/C-mediated depropargylation of propargyl ethers/amines in water
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Propargyl ethers and amines are effectively depropargylated to the parent alcohols or amines via a C-O/C-N bond cleavage catalyzed by 10% Pd/C in water. This simple, facile, and inexpensive methodology could be utilized for the selective removal of propargyl groups from a variety of aryl ethers and amines.
- Rambabu,Bhavani,Swamy, Nalivela Kumara,Basaveswara Rao,Pal, Manojit
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p. 1169 - 1173
(2013/04/10)
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- Mild and highly selective palladium-catalyzed monoarylation of ammonia enabled by the use of bulky biarylphosphine ligands and palladacycle precatalysts
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A method for the Pd-catalyzed arylation of ammonia with a wide range of aryl and heteroaryl halides, including challenging five-membered heterocyclic substrates, is described. Excellent selectivity for monoarylation of ammonia to primary arylamines was achieved under mild conditions or at rt by the use of bulky biarylphosphine ligands (L6, L7, and L4) as well as their corresponding aminobiphenyl palladacycle precatalysts (3a, 3b, and 3c). As this process requires neither the use of a glovebox nor high pressures of ammonia, it should be widely applicable.
- Cheung, Chi Wai,Surry, David S.,Buchwald, Stephen L.
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supporting information
p. 3734 - 3737
(2013/08/23)
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- SUBSTITUTED QUINAZOLINE DERIVATIVES AND THEIR USE AS INHIBITORS
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The use of a compound of formula (I) 1 or a salt, ester or amide thereof; where X is O, or S, S(O) or S(O)2, or NR6 where R6 is hydrogen or C1-6 alkyl,; R5 is an optionally substituted 5-membered heteroaromatic ring, R1, R2 ,R3, R4 are independently selected from various specified moieties, in the preparation of a medicament for use in the inhibition of aurora 2 kinase. Certain compounds are novel and these, together with pharmaceutical compositions containing them are also described and claimed
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- Hydrogenation on granular palladium-containing catalysts: II. Hydrogenation of nitroheterocyclic compounds
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Nitroheterocyclic compounds were reduced in a classical reactor with an agitator equipped with a cell for fixed bed of catalyst. As catalysts were applied granular palladium catalysts (0.5% of Pd on γ-Al2O 3 and 2% of Pd on granulated carbon). Anilines and 3-amino-2(1H)-pyridones were obtained in high yield at reduction of the appropriate nitro compounds, and the activity of the catalyst samples only slightly decreased. Yet aminopyrazoles and aminoimidazoles obtained by hydrogenation on palladium were very sensitive to the presence of air even as hydrochlorides. In the course of hydrogenation of nitropyrazoles and nitroimidazoles the activity of the catalyst markedly decreased.
- Kislyi,Tolkacheva,Semenov
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p. 269 - 271
(2007/10/03)
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- Preparation of 3-sulphenylmaleimides
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A process for the preparation of a 3-sulphenylmaleimide of the formula STR1 in which R1 is alkyl, or optionally substituted cycloalkyl or aralkyl, and R2 is optionally substituted alkyl, cycloalkyl, aryl or aralkyl, comprising reacting a 3-sulphenylsuccinimide of the formula STR2 with an equimolar amount of hydrogen peroxide in the presence of a lower alkanecarboxylic acid. The compounds are fungicidal and those are new where R2 is not alkyl, or where R1 is not alkyl while R2 is optionally substituted phenyl.
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- Preparation of aryl trifluoromethyl ethers
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A one-step process for the synthesis of aryl trifluoromethyl ethers by reacting phenol or certain substituted phenols with a perhalomethane and hydrogen fluoride is provided. The compounds produced by the process of this invention are useful intermediates in the production of dyestuffs and pharmaceuticals.
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