- ELECTROCHEMICAL CHLORINATION OF AMINES
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We have studied the laws governing the electrochemical chlorination of primary and secondary amines in aqueous solution on a ruthenium-titanium anode under conditions of diaphragm electrolysis.It was found that in order to ensure the most complete conversion of the amines into the corresponding chloramines it is necessary to add NaHCO3 to the electrolyte .Under the conditions of electrolysis primary amines are converted almost quantitatively into dichloramines.High yields of the N-chloro-derivatives of secondary amines can be obtained with high current densities and concentrations of NaCl.
- Petrosyan, V. A.,Lyalin, B. V.,Smetanin, A. V.
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- Copper-catalyzed one-pot oxidative amidation between methylarenes and amines
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A new method for the direct one-pot oxidative amidation between methylarenes and amines catalyzed by copper has been developed. This method integrates methylarene oxidation and amide bond formation, which are usually accomplished separately, into a single operation. In addition, the reaction provides a relatively high yield and has a wide substrate scope. Moreover, the starting reagents are abundant and available in a convenient way at a cheaper price.
- Yang, Yuhang,Gu, Jiajia,Fang, Zheng,Yang, Zhao,Wei, Ping,Guo, Kai
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- A General Approach to Site-Specific, Intramolecular C?H Functionalization Using Dithiocarbamates
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Intramolecular hydrogen atom transfer is an established approach for the site-specific functionalization of unactivated, aliphatic C?H bonds. Transformations using this strategy typically require unstable intermediates formed using strong oxidants and have mainly targeted C?H halogenations or intramolecular aminations. Herein, we report a site-specific C?H functionalization that significantly increases the synthetic scope and convergency of reactions proceeding via intramolecular hydrogen atom transfer. Stable, isolable N-dithiocarbamates are used as precursors to amidyl radicals formed via either light or radical initiation to efficiently deliver highly versatile alkyl dithiocarbamates across a wide range of complex structures.
- Na, Christina G.,Alexanian, Erik J.
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- Two-step continuous flow synthesis of amide via oxidative amidation of methylarene
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A green and efficient method for the synthesis of amides has been developed through oxidative amidation between methylarenes with amines in a two-step continuous flow system. This method integrates methylarene oxidation and amide formation into a single operation which is usually accomplished separately. Oxidation with tert-butyl hydroperoxide (TBHP) as “green” oxidant, the synthesis of amides under mild reaction conditions in continuous flow system and the utilization of methylarenes as starting material make this methodology novel and environment friendly. The practical value of this method is highlighted through the synthesis of high-profile pharmaceutical agents, acetylprocainamide.
- Fang, Zheng,Guo, Kai,He, Wei,Liu, Chengkou,Shi, Tingting,Yang, Yuhang,Yang, Zhao,Zhang, Zhimin
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- Practical and regioselective amination of arenes using alkyl amines
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The formation of carbon–nitrogen bonds for the preparation of aromatic amines is among the top five reactions carried out globally for the production of high-value materials, ranging from from bulk chemicals to pharmaceuticals and polymers. As a result of this ubiquity and diversity, methods for their preparation impact the full spectrum of chemical syntheses in academia and industry. In general, these molecules are assembled through the stepwise introduction of a reactivity handle in place of an aromatic C–H bond (that is, a nitro group, halogen or boronic acid) and a subsequent functionalization or cross-coupling. Here we show that aromatic amines can be constructed by direct reaction of arenes and alkyl amines using photocatalysis, without the need for pre-functionalization. The process enables the easy preparation of advanced building blocks, tolerates a broad range of functionalities, and multigram scale can be achieved via a batch-to-flow protocol. The merit of this strategy as a late-stage functionalization platform has been demonstrated by the modification of several drugs, agrochemicals, peptides, chiral catalysts, polymers and organometallic complexes.
- Ruffoni, Alessandro,Juliá, Fabio,Svejstrup, Thomas D.,McMillan, Alastair J.,Douglas, James J.,Leonori, Daniele
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p. 426 - 433
(2019/05/01)
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- Chemo- and Regioselective Functionalization of Isotactic Polypropylene: A Mechanistic and Structure-Property Study
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Polyolefins represent a high-volume class of polymers prized for their attractive thermomechanical properties, but the lack of chemical functionality on polyolefins makes them inadequate for many high-performance engineering applications. We report a metal-free postpolymerization modification approach to impart functionality onto branched polyolefins without the deleterious chain-coupling or chain-scission side reactions inherent to previous methods. The identification of conditions for thermally initiated polyolefin C-H functionalization combined with the development of new reagents enabled the addition of xanthates, trithiocarbonates, and dithiocarbamates to a variety of commercially available branched polyolefins. Systematic experimental and kinetic studies led to a mechanistic hypothesis that facilitated the rational design of reagents and reaction conditions for the thermally initiated C-H xanthylation of isotactic polypropylene (iPP) within a twin-screw extruder. A structure-property study showed that the functionalized iPP adheres to polar surfaces twice as strongly as commercial iPP while demonstrating similar tensile properties. The fundamental understanding of the elementary steps in amidyl radical-mediated polyolefin functionalization provided herein reveals key structure-reactivity relationships for the design of improved reagents, while the demonstration of chemoselective and scalable iPP functionalization to realize a material with improved adhesion properties indicates the translational potential of this method.
- Williamson, Jill B.,Na, Christina G.,Johnson, Robert R.,Daniel, William F. M.,Alexanian, Erik J.,Leibfarth, Frank A.
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supporting information
p. 12815 - 12823
(2019/08/20)
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- Copper-catalyzed one-pot oxidative amidation of alcohol to amide via C-H activation
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A one-pot oxidative amidation of both aliphatic and aromatic alcohols with N-chloramines, prepared in situ from many types of primary and secondary amines, was developed. This cross-coupling reaction integrates alcohol oxidation and amide bond formation, which are usually accomplished separately, into a single operation. And it was green, simple and convenient, which has a wide substrate scope and makes use of cheap, abundant, and easily available reagents. The practical value of this method is highlighted through the synthesis of a high-profile pharmaceutical agent, acetylprocainamide.
- Gu, Jiajia,Fang, Zheng,Yang, Yuhang,Yang, Zhao,Wan, Li,Li, Xin,Wei, Ping,Guo, Kai
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p. 89413 - 89416
(2016/10/03)
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- Titanium-mediated amination of Grignard reagents using primary and secondary amines
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Make it, then break it: N-chlorosuccinimide (NCS) was employed as the oxidant in the synthesis of aniline derivatives using the title transformation (see scheme). Functionalization was well tolerated on both the amine and Grignard reagent. An androgen receptor agonist and several analogues were synthesized to demonstrate the utility of this method.
- Barker, Timothy J.,Jarvo, Elizabeth R.
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supporting information; experimental part
p. 8325 - 8328
(2011/10/31)
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- Kinetics of the Formation, Decomposition, and Disproportionation Reactions of N-Chlorobutylamines
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The formation of N-chlorobutylamines is a reaction of order one with respect to hypochlorite and amine, and order -1 with respect to OH-.Kinetic studies show that N-chlorobutylamines undergo decomposition in basic aqueous media, and disproportionation (with formation of N,N-dichloramines) in acidic media, mechanisms are put forward for both these processes.
- Antelo, Juan M.,Arce, Florencio,Castro, Maria C.,Crugeiras, Juan,Perez-Moure, Juan C.,Rodriguez, Pilar
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p. 703 - 718
(2007/10/02)
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- Photo-promoted Oxidation of Alcohols with Aliphatic N-Chloroamines
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Irradiation of N,N-dichloro-t-butylamine (1) with alcohols, especially alcohols of benzylic type, in CCl4 was found to give the corresponding ketones and aldehydes with quantitative formation of t-butylamine hydrochloride.The photoreaction of 1-phenylethanol with (1) in cyclohexane or toluene, however, gives mainly solvent-chlorinated products together with a low yield of acetophenone.The oxidation is suppressed by HCl scavengers (triethylamine or epichlorohydrin) and accelerated by the addition of HCl irrespective of irradiation.The irradiation may induce generation of Cl and then HCl, the latter exerting autocatalysis for the oxidation in the dark.An ionic mechanism via protonated (1) and alkyl hypochlorite is postulated and discussed.
- Ogata, Yoshiro,Kimura, Makoto
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p. 947 - 950
(2007/10/02)
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