- Combined Cyanoborylation, C-H Activation Strategy for Styrene Functionalization
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A one-pot multicomponent copper-catalyzed protocol for borylation/ortho-cyanation of styrene derivatives followed by a Suzuki-Miyaura coupling provides a platform to explore the factors that control the selectivity between distal or proximal functionalization of arenes. The development of divergent nitrile-directed C-H functionalization (acetoxylation, pivalation, and methoxylation) offers an effective approach to rapidly increase synthetic complexity. Finally, the development of a mild reductive decyanation allows a traceless method to access functionalized biaryl motifs.
- Ansel, Annabel Q.,Montgomery, John
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supporting information
p. 8538 - 8543
(2020/11/12)
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- Borrowing Hydrogen-Mediated N-Alkylation Reactions by a Well-Defined Homogeneous Nickel Catalyst
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We report herein a well-defined and bench-stable azo-phenolate ligand-coordinated nickel catalyst which can efficiently execute N-alkylation of a variety of anilines by alcohol. We demonstrate that the redox-active azo ligand can store hydrogen generated during alcohol oxidation and redelivers the same to an in-situ-generated imine bond to result in N-alkylation of amines. The reaction has wide scope, and a large array of alcohols can directly couple to a variety of anilines. Mechanistic studies including deuterium labeling to the substrate establishes the borrowing hydrogen method from alcohols and pinpoints the crucial role of the redox-active azo moiety present on the ligand backbone. Isolation of the ketyl intermediate in its trapped form with a radical quencher and higher kH/kD for the alcohol oxidation step suggest altogether a hydrogen-atom transfer (HAT) to the reduced azo backbone to pave alcohol oxidation as opposed to the conventional metal-ligand bifunctional mechanism. This example clearly demonstrates that an inexpensive base metal catalyst can accomplish an important coupling reaction with the help of a redox-active ligand backbone.
- Bains, Amreen K.,Kundu, Abhishek,Yadav, Sudha,Adhikari, Debashis
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p. 9051 - 9059
(2019/10/02)
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- Chemoselectivity for Alkene Cleavage by Palladium-Catalyzed Intramolecular Diazo Group Transfer from Azide to Alkene
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Alkenes can be cleaved by means of the (3+2) cycloaddition and subsequent cycloreversion of 1,3-dipoles, classically ozone (O3), but the azide (R?N3) variant is rare. Chemoselectivity for these azide to alkene diazo group transfers (DGT) is typically disfavored, thus limiting their synthetic utility. Herein, this work discloses a palladium-catalyzed intramolecular azide to alkene DGT, which grants chemoselectivity over competing aziridination. The data support a catalytic cycloreversion mechanism distinct from other known metal-catalyzed azide/alkene reactions: nitrenoid/metalloradical and (3+2) cycloadditions. Kinetics experiments reveal an unusual mechanistic profile in which the catalyst is not operative during the rate-controlling step, rather, it is active during the product-determining step. Catalytic DGT was used to synthesize N-heterocyclic quinazolinones, a medicinally relevant structural core. We also report on the competing aziridination and subsequent ring expansion to another N-heterocyclic core structure of interest, benzodiazepinones.
- Frost, Grant B.,Mittelstaedt, Michaela N.,Douglas, Christopher J.
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supporting information
p. 1727 - 1732
(2019/01/09)
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- Mechanistic Studies of Hydride Transfer to Imines from a Highly Active and Chemoselective Manganate Catalyst
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We introduce a highly active and chemoselective manganese catalyst for the hydrogenation of imines. The catalyst has a large scope, can reduce aldimines and ketimines, and tolerates a variety of functional groups, among them hydrogenation sensitive examples such as an olefin, a ketone, nitriles, nitro groups, and an aryl iodo substituent or a benzyl ether. We could investigate the transfer step between imines and the hydride complex in detail. We found that double deprotonation of the ligand is essential and excess base does not lead to a higher rate in the transfer step. We identified the actual hydrogenation catalyst as a K-Mn-bimetallic species and could obtain a structure of the K-Mn complex formed after hydride transfer by X-ray analysis. NMR experiments indicate that the hydride transfer is a well-defined reaction, which is first order in imine, first order in the bimetallic (K-Mn) hydride, and independent in rate from the concentration of the potassium base. We propose an outer-sphere mechanism in which protons do not seem to be involved in the rate-determining step, leading to a transiently negatively charged nitrogen atom in the substrate which reacts rapidly with HOtBu (2-methylpropan-2-ol) to produce the amine. This is based on several observations, such as no dependency of the reaction rate on the HOtBu concentration, no observable manganese amide complex, and a high reaction constant in a conducted Hammett study. Furthermore, hydrogen transfer of the catalytic cycle was experimentally probed and monitored by NMR with subsequent quantitative regeneration of the catalyst by H2.
- Freitag, Frederik,Irrgang, Torsten,Kempe, Rhett
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supporting information
p. 11677 - 11685
(2019/08/20)
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- Oxalic amide ligands, and uses thereof in copper-catalyzed coupling reaction of aryl halides
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The present invention provides oxalic amide ligands and uses thereof in copper-catalyzed coupling reaction of aryl halides. Specifically, the present invention provides a use of a compound represented by formula I, wherein definitions of each group are described in the specification. The compound represented by formula I can be used as a ligand in copper-catalyzed coupling reaction of aryl halides for the formation of C—N, C—O and C—S bonds.
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Page/Page column 77-78
(2020/01/09)
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- Synthesis of Quinazolines via an Iron-Catalyzed Oxidative Amination of N-H Ketimines
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An efficient synthesis of quinazolines based on an iron-catalyzed C(sp3)-H oxidation and intramolecular C-N bond formation using tert-BuOOH as the terminal oxidant is described. The reaction of readily available 2-alkylamino benzonitriles with various organometallic reagents led to 2-alkylamino N-H ketimine species. The FeCl2-catalyzed C(sp3)-H oxidation of the alkyl group employing tert-BuOOH followed by intramolecular C-N bond formation and aromatization afforded a wide variety of 2,4-disubstituted quinazolines in good to excellent yields.
- Chen, Cheng-Yi,He, Fengxian,Tang, Guangrong,Yuan, Huiqing,Li, Ning,Wang, Jinmin,Faessler, Roger
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p. 2395 - 2401
(2018/02/23)
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- Cu-catalyzed reduction of azaarenes and nitroaromatics with diboronic acid as reductant
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A ligand-free copper-catalyzed reduction of azaarenes with diboronic acid as reductant in an aprotic solvent under mild conditions has been developed. Most interestingly, the nitroazaarenes could be reduced exclusively to give the corresponding amines without touching the azaarene moieties. Furthermore, the reductive amination of aromatic nitro compounds and aromatic aldehydes has also been realized. A series of hydrogenated azaarenes and secondary amines were obtained with good functional group tolerance.
- Pi, Danwei,Zhou, Haifeng,Zhou, Yanmei,Liu, Qixing,He, Renke,Shen, Guanshuo,Uozumi, Yasuhiro
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p. 2121 - 2129
(2018/03/23)
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- Water as a hydrogen source in palladium-catalyzed reduction and reductive amination of nitroarenes mediated by diboronic acid
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An unprecedented palladium-catalyzed chemoselective reduction and reductive amination of nitroarenes with water as a hydrogen source mediated by diboronic acid have been discovered. A series of aryl amines containing various reducible functional groups were obtained in good to excellent yields.
- Zhou, Yanmei,Zhou, Haifeng,Liu, Sensheng,Pi, Danwei,Shen, Guanshuo
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p. 3898 - 3904
(2017/06/13)
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- Borrowing Hydrogen Methodology for N-Benzylation using a π-Benzylpalladium System in Water
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We demonstrate a borrowing hydrogen methodology using the unique reactivity of the π-benzylpalladium system in water, which offers an efficient and environmentally friendly N-monobenzylation of electron-deficient anilines or 2-aminopyridine with non-activated benzylic alcohols under neutral conditions. The crossover experiment using benzyl-α,α-d2 alcohol and 3-methylbenzyl alcohol afforded H/D scrambling products, suggesting that the borrowing hydrogen pathway occurred in our catalytic system. Our simple protocol can accomplish a gram scale reaction of 2-aminobenzonitrile (76 % isolated yield), and is performed with the use of only 1 mol % Pd(OAc)2 and 2 mol % TPPMS without other additives in water.
- Hikawa, Hidemasa,Koike, Toshitaka,Izumi, Kyoko,Kikkawa, Shoko,Azumaya, Isao
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p. 784 - 791
(2016/03/09)
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- A General and Direct Reductive Amination of Aldehydes and Ketones with Electron-Deficient Anilines
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In our ongoing efforts in preparing tool compounds for investigating and controlling the biosynthesis of phenazines, we recognized the limitations of existing protocols for C-N bond formation of electron-deficient anilines when using reductive amination. After extensive optimization, we have established three robust and scalable protocols for the reductive amination of ketones with electron-deficient anilines, by using either BH3·THF/AcOH/CH2Cl2 (method A), with reaction times of several hours, or the more powerful combinations BH3·THF/TMSCl/DMF (method B) and NaBH4/TMSCl/DMF (method C), which give full conversions for most substrates within 10 to 25 minutes. The scope and limitations of these reactions have been defined for 12 anilines and 14 ketones.
- Pletz, Jakob,Berg, Bernhard,Breinbauer, Rolf
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supporting information
p. 1301 - 1317
(2016/05/02)
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- Fe@Pd/C: An efficient magnetically separable catalyst for direct reductive amination of carbonyl compounds using environment friendly molecular hydrogen in aqueous reaction medium
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Direct reductive amination of carbonyl compounds with variety of amines has been reported by using magnetically separable Fe@Pd/C as an efficient catalyst in aqueous reaction medium. The developed methodology offers synthesis of various secondary and tertiary amines using different aldehydes and ketones with amines giving excellent yield. Moreover, the magnetically separable Fe@Pd/C catalyst was easily separated from reaction mixture and can be recycled for further reaction.
- Patil, Nilesh M.,Bhanage, Bhalchandra M.
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p. 182 - 189
(2015/03/30)
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- CuI/Oxalic Diamide Catalyzed Coupling Reaction of (Hetero)Aryl Chlorides and Amines
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A class of oxalic diamides are found to be effective ligands for promoting CuI-catalyzed aryl amination with less reactive (hetero)aryl chlorides. The reaction proceeds at 120 °C with K3PO4 as the base in DMSO to afford a wide range of (hetero)aryl amines in good to excellent yields. The bis(N-aryl) substituted oxalamides are superior ligands to N-aryl-N′-alkyl substituted or bis(N-alkyl) substituted oxalamides. Both the electronic nature and the steric property of the aromatic rings in ligands are important for their efficiency.
- Zhou, Wei,Fan, Mengyang,Yin, Junli,Jiang, Yongwen,Ma, Dawei
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supporting information
p. 11942 - 11945
(2015/10/06)
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- N-Alkylation of amines with alcohols over nanosized zeolite beta
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Direct N-alkylation of amines with alcohols was successfully performed by using nanosized zeolite beta, which showed the highest catalytic activity among other conventional zeolites. This method has several advantages, such as eco-friendliness, moderate to high yields, and simple work-up procedure. The catalyst was successfully recovered and reused without significant loss of activity and only water is produced as co-product. In addition, imines were also efficiently prepared from the tandem reactions of amines with 2-, 3- and 4-nitrobenzyl alcohols using nanosized zeolite beta.
- Reddy, Marri Mahender,Kumar, Macharla Arun,Swamy, Peraka,Naresh, Mameda,Srujana, Kodumuri,Satyanarayana, Lanka,Venugopal, Akula,Narender, Nama
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supporting information
p. 3474 - 3483
(2013/12/04)
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- Palladium(II)-catalyzed cyclization reaction of 2-(Alk-2'-ynyloxy) benzonitriles or 2-(Alk-2'-ynylamino)benzonitriles: A facile way to 2H-chromene and 1,2-dihydroquinoline derivatives
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An efficient synthesis of 2H-chromenes and 1,2-dihydroquinolines from palladium(II)-catalyzed tandem reactions of 2-(alk-2'-ynyloxy)benzonitriles or 2-(alk-2'-ynylamino)benzonitriles was developed. This tandem reaction involves an intermolecular trans-acetoxypalladation of an alkyne followed by an addition to the nitrile group to quench the carbon-palladium bond and complete the catalytic cycle without the necessity of a redox system.
- Xi, Guoqin,Han, Xiuling,Lu, Xiyan
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supporting information
p. 2701 - 2705,5
(2012/12/12)
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- Two Component Recyclable Heterogeneous Catalyst, Process for Preparation Thereof and its Use for Preparation of Amines
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The invention describes the development of highly efficient, recyclable two component system, CuAl-hydrotalcite/rac 1,1′-Binaphthalene-2,2′-diol catalytic system for the N-alkylation of electron deficient aryl chlorides in presence of potassium carbonate as a base at room temperature in 3-6 h, wherein the process is provided for the preparation of various secondary amines via C—N coupling reaction of aliphatic amines(aliphatic open chain, acyclic, benzyl amines and heterocyclic amines) with various aryl chlorides.
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Page/Page column 4
(2012/01/13)
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- Amination of alcohols catalyzed by copper-aluminium Hydrotalcite: A green synthesis of amines
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Copper-aluminium hydrotalcite (CuAl-HT)/K2CO3 has been employed in the activation of various benzyl alcohols with benzylamines to afford the corresponding amines in good to high yields. Experimentation showed that the reaction takes place through sequential transformations: the oxidation of alcohols into carbonyl compounds, imine formation between amines and carbonyl compounds, and then reduction of imines to amines, heterogeneously catalyzed by non-noble Cu-Al HT catalyst in a one-pot and straightforward fashion. The process was further extended to amination of alcohols with anilines, which are often resistant to alkylation reactions when substituted with strong electron-withdrawing groups.
- Likhar, Pravin R.,Arundhathi, Racha,Kantam, Mannepalli Lakshmi,Prathima, Parvathaneni Sai
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experimental part
p. 5383 - 5389
(2010/02/28)
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- An efficient base-mediated intramolecular condensation of 2-(disubstituted amino)-benzonitriles to 3-aminoindoles
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A concise and versatile method for the preparation of 3-aminoindoles from 2-(disubstituted amino)-benzonitriles is described, and in situ functionalizations were illustrated.
- Seong, Churl Min,Park, Chul Min,Choi, Jinil,Park, No Sang
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scheme or table
p. 1029 - 1031
(2009/05/27)
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- A recyclable Cu/Al-HT catalyst for amination of aryl chlorides
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A simple Cu/Al-HT catalyzed amination of aryl chlorides with primary and secondary aromatic amines has been developed. This ligand-free heterogeneous Cu/Al-HT catalyst, in conjunction with base, also efficiently works for the amination of aryl chlorides with cycloalkylamines. This method tolerates a variety of functional groups and does not require an expensive additive.
- Likhar, Pravin R.,Arundhathi,Kantam, M. Lakshmi
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p. 3911 - 3914
(2008/02/03)
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- Substituted compounds derived from N-(benzyl)phenylacetamide, preparation and uses
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This invention relates to poly-substituted derivatives of the N-(benzyl)phenylacetamide type, pharmaceutical compositions comprising same, therapeutic uses thereof, more particularly in the fields of human and animal health. This invention also relates to a process for the preparation of such derivatives.
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Page/Page column 44
(2010/10/20)
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- New synthesis of 3-substituted indazoles from 3-trimethylsilylindazole
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Reaction of aryl aldehydes with 3-trimethylsilylindazole in the presence of CsF easily gave the corresponding 3-(arylhydroxymethyl)indazoles in good to moderate yields.
- Hari, Yoshiyuki,Shoji, Yoshimichi,Aoyama, Toyohiko
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p. 1183 - 1186
(2007/10/03)
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- Ring forming reactions of imines of 2-aminobenzaldehyde and related compounds
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By addition of organometallic reagents to 2-aminobenzonitriles followed by quenching with suitable electrophiles (acyl halides, aldehydes and ketones), several types of 6-membered benzofused aromatic and non-aromatic nitrogen heterocycles could be obtained. Rearrangements leading to 1,2-dihydro-3H-1,4-benzodiazepin-3-ones and preparation of various quinazolines are described.
- Wiklund, Per,Bergman, Jan
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p. 367 - 372
(2007/10/03)
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- The stereochemistry of organometallic compounds. XLIII* rhodium-catalysed reactions of 2-(alkenyloxy)benzylamines and 2-(N-allyl-N-benzylamino)benzylamine
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Reactions of 2-(allyloxy)benzylamines with H2/CO in the presence of rhodium catalysts give 1,3-benzoxazines, and 2-(N-allyl-N-benzylamino)benzylamine gives a quinazoline. These reactions have been shown to involve allylic cleavage followed by regioselective carbonylation at the internal carbon atom as demonstrated by crossover experiments. Reactions of longer chain (alkenyloxy)benzylamines under similar conditions give polymeric material.
- Campi, Eva M.,Jackson, W. Roy,McCubbin, Quentin J.,Trnacek, Andrew E.
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p. 219 - 230
(2007/10/03)
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- A convenient synthetic route to 2-diphenylphosphinoyl-3-hydroxy, amino and alkyl indole derivatives
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A series of 2-diphenylphosphinoyl-3-hydroxy, amino and alkyl indole derivatives have been efficiently prepared by base-induced intramolecular cyclization of aromatic Horner-Wittig reagents containing carboxamido, cyano and oxo groups, respectively.
- Couture, Axel,Deniau, Eric,Gimbert, Yves,Grandclaudon, Pierre
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p. 1431 - 1444
(2007/10/02)
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- A NEW SYNTHESIS OF 4-AMINO-2-QUINOLINONES
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Addition of Grignard or organolithium reagents to N-(α-haloacyl)-N-alkylsubstituted anthranilonitriles (e.g.N-(2-bromopropionyl)-N-methyl-2-cyanoaniline)induced anion formation followed by cyclization to 4-amino-2-quinolinones (e.g. 4-amino-1,3-dimethyl-2-quinolinone (10)).Substrates lacking α-hydrogen atoms, such as N-α-bromoisobutyryl)-2-cyanoaniline, also yielded 3,3-dimethylquinolinedione (9b) by cyclization.In these cases the initial step is a halogen-metal exchange reaction.
- Bergman, Jan,Brynolf, Anna,Vuorinen, Eino
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p. 3689 - 3696
(2007/10/02)
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- CLEAVAGE OF THE N-N BOND IN 1-SUBSTITUTED INDAZOLES UNDER THE INFLUENCE OF ARYLLITHIUM COMPOUNDS
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Upon reaction with aryllithium compounds (phenyllithium and m-tolyllithium) m-methyl- and 1-isopropylindazoles undergo cleavage at the N-N bond to give N-substituted 2-aminobenzophenones.The heterocyclic ring of 1-isopropyl-3-phenylindazole also undergoes cleavage at this bond under the influence of phenyllithium.
- Tertov, B. A.,Onishchenko, P. P.,Koshchienko, Yu. V.,Suvorova, G. M.,Malysheva, E. N.
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p. 823 - 826
(2007/10/02)
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