- Oxidized multiwalled nanotubes as efficient carbocatalyst for the general synthesis of azines
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The carbocatalytic synthesis of azines (N-N linked diimines) by mild-oxidized multiwalled carbon nanotubes catalyst (oxMWNT) is presented. The material, just with a 5 %wt. loading, is able to carry out a smooth room-temperature metal-free condensation of
- Agnoli, Stefano,Alemán, José,Blanco, Matías,Fraile, Alberto,Valle-Amores, Miguel A.
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p. 174 - 183
(2022/02/02)
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- Ruthenium catalyzed β-selective alkylation of vinylpyridines with aldehydes/ketonesviaN2H4mediated deoxygenative couplings
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Umpolung (polarity reversal) tactics of aldehydes/ketones have greatly broadened carbonyl chemistry by enabling transformations with electrophilic reagents and deoxygenative functionalizations. Herein, we report the first ruthenium-catalyzed β-selective alkylation of vinylpyridines with both naturally abundant aromatic and aliphatic aldehyde/ketonesviaN2H4mediated deoxygenative couplings. Compared with one-electron umpolung of carbonyls to alcohols, this two-electron umpolung strategy realized reductive deoxygenation targets, which were not only applicable to the regioselective alkylation of a broad range of 2/4-alkene substituted pyridines, but also amenable to challenging 3-vinyl and steric-embedded internal pyridines as well as their analogous heterocyclic structures.
- Lv, Leiyang,Li, Chao-Jun
-
p. 2870 - 2875
(2021/03/14)
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- Addition reactions of organic carbanion equivalents via hydrazones in water
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The addition of organometallic reagents to unsaturated bonds is one of the most powerful tools for carbon–carbon bond formations. Alkylation through organometallic reagents requires stoichiometric quantity of metal and tedious anhydrous operation in most cases. Here, we report “umpolung” nucleophilic additions of hydrazones to Michael acceptors, carbonyls and imines in water. Under the catalysis of ruthenium(II), the addition reactions could be carried out in pure water to provide various alkylation products in moderate to good yields.
- Wang, Yi-Zhan,Liu, Qi,Cheng, Liang,Yu, Song-Chen,Liu, Li,Li, Chao-Jun
-
supporting information
(2021/01/11)
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- Palladium-Catalyzed Defluorinative Alkylation of gem-Difluorocyclopropanes: Switching Regioselectivity via Simple Hydrazones
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Conventional approaches for Pd-catalyzed ring-opening cross-couplings of gem-difluorocyclopropanes with nucleophiles predominantly deliver the β-fluoroalkene scaffolds (linear selectivity). Herein, we report a cooperative strategy that can completely switch the reaction selectivity to give the alkylated α-fluoroalkene skeletons (branched selectivity). The unique reactivity of hydrazones that enables analogous inner-sphere 3,3′-reductive elimination driven by denitrogenation, as well as the assistance of steric-embedded N-heterocyclic carbene ligand, are the key to switch the regioselectivity. A wide range of hydrazones derived from naturally abundant aryl and alkyl aldehydes are well applicable, and various gem-difluorocyclopropanes, including modified pharmaceutical and biological molecules, can be efficiently functionalized with high value alkylated α-fluorinated alkene motifs under mild conditions.
- Lv, Leiyang,Li, Chao-Jun
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supporting information
p. 13098 - 13104
(2021/05/03)
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- Submonomer synthesis of peptoids containingtrans-inducingN-imino- andN-alkylamino-glycines
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The use of hydrazones as a new type of submonomer in peptoid synthesis is described, giving access to peptoid monomers that are structure-inducing. A wide range of hydrazones were found to readily react with α-bromoamides in routine solid phase peptoid submonomer synthesis. Conditions to promote a one-pot cleavage of the peptoid from the resin and reduction to the correspondingN-alkylamino side chains were also identified, and both theN-imino- andN-alkylamino glycine residues were found to favor thetrans-amide bond geometry by NMR, X-ray crystallography, and computational analyses.
- Davern, Carolynn M.,Ison, Elon A.,Lowe, Brandon D.,Proulx, Caroline,Rosfi, Adam
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p. 8401 - 8410
(2021/06/28)
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- Copper-Catalyzed Conjugate Addition of Carbonyls as Carbanion Equivalent via Hydrazones
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Copper-catalyzed conjugate addition is a classic method for forming new carbon-carbon bonds. However, copper has never showed catalytic activity for umpolung carbanions in hydrazone chemistry. Herein, we report a facile conjugate addition of hydrazone catalyzed by readily available copper complexes at room temperature. The employment of mesitylcopper(I) and electron-rich phosphine bidentate ligand is a key factor affecting reactivity. The reaction allows various aromatic hydrazones to react with diverse conjugated compounds to produce 1,4-adducts in yields of about 20 to 99%.
- Luo, Siyi,Peng, Marie,Querard, Pierre,Li, Chen-Chen,Li, Chao-Jun
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p. 13111 - 13117
(2021/09/18)
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- N-Amino-1,8-Naphthalimide is a Regenerated Protecting Group for Selective Synthesis of Mono-N-Substituted Hydrazines and Hydrazides
-
A new route to synthesis of various mono-N-substituted hydrazines and hydrazides by involving in a new C?N bond formation by using N-amino-1,8-naphthalimide as a regenerated precursor was invented. Aniline and phenylhydrazines are reproduced upon reacting these individually with 1,8-naphthalic anhydride followed by hydrazinolysis. The practicality and simplicity of this C?N dihalo alkanes; developed a synthon for bond formation protocol was exemplified to various hydrazines and hydrazides. N-amino-1,8-naphthalimide is suitable synthon for transformation for selective formation of mono-substituted hydrazine and hydrazide derivatives. Those are selective mono-amidation of hydrazine with acid halides; mono-N-substituted hydrazones from aldehydes; synthesis of N-aminoazacycloalkanes from acetohydrazide scaffold and inserted to hydroxy derivatives; distinct synthesis of N,N-dibenzylhydrazines and N-benzylhydrazines from benzyl halides; synthesis of N-amino-amino acids from α-halo esters. Ecofriendly reagent N-amino-1,8-naphthalimide was regenerated with good yields by the hydrazinolysis in all procedures.
- Manoj Kumar, Mesram,Venkataramana, Parikibanda,Yadagiri Swamy, Parikibanda,Chityala, Yadaiah
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supporting information
p. 17713 - 17721
(2021/11/10)
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- Switch in Selectivity for Formal Hydroalkylation of 1,3-Dienes and Enynes with Simple Hydrazones
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Controlling reaction selectivity is a permanent pursuit for chemists. Regioselective catalysis, which exploits and/or overcomes innate steric and electronic bias to deliver diverse regio-enriched products from the same starting materials, represents a powerful tool for divergent synthesis. Recently, the 1,2-Markovnikov hydroalkylation of 1,3-dienes with simple hydrazones was reported to generate branched allylic compounds when a nickel catalyst was used. As part of the effort, shown here is that a complete switch of Markovnikov to anti-Markovnikov addition is obtained by changing to a ruthenium catalyst, thus providing direct and efficient access to homoallylic products exclusively. Isotopic substitution experiments indicate that no reversible hydro-metallation across the metal-π-allyl system occurred under ruthenium catalysis. Moreover, this protocol is applicable to the regiospecific hydroalkylation of the distal C=C bond of 1,3-enynes.
- Li, Chao-Jun,Lv, Leiyang,Qiu, Zihang,Yu, Lin
-
supporting information
p. 6466 - 6472
(2020/03/13)
-
- Structural studies of 2,5-disubstituted 1,3,4-thiadiazole derivatives from dithioesters under the mild condition: Studies on antioxidant, antimicrobial activities, and molecular docking
-
A series of 2,5-disubstituted 1,3,4-thiadiazole was synthesized and evaluated for their antioxidant and molecular docking studies. These molecules were efficiently synthesized under mild and inexpensive starting material. Construction of these molecules developed using substituted aldehydes and substituted dithioesters in presence of NCS (N-Chorosuccinimide). The compounds 4a, 4b, 4c, 4f, and 4k showed good antibacterial and antioxidant activity among which, 4k possess excellent antibacterial and antioxidant activity. The results of antioxidant activity studies revealed that compound 4k manifested profound antioxidant potential. The molecular docking study was performed with respective newly synthesized compounds to ascertain the binding mode of 4k with respect to the critical proteins involved in biosynthesis and metabolic pathways.
- Gowda, Kemparaje,Kanchugarkoppal, Rangappa S.,Kempegowda, Mantelingu,Nagarakere, Sandhya C.,Rangappa, Shobith,Swarup, Hassan A.
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- Efficient Multigram Approach to Acetylenes and CF3-ynones Starting from Dichloroalkenes Prepared by Catalytic Olefination Reaction (COR)
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A novel approach to terminal acetylenes based on catalytic olefination reaction COR of arylaldehydes to form dichloroalkenes followed by treatment with nBuLi was elaborated. This method is atom economical and displays high yields and effectivity. The corresponding alkynes can be prepared in up to 97 % yield. One pot procedure towards CF3-ynones was elaborated to provide these products in up to 87 % yield starting from dichloroalkenes.
- Muzalevskiy, Vasiliy M.,Sizova, Zoia A.,Diusenov, Arstan I.,Shastin, Alexey V.,Nenajdenko, Valentine G.
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supporting information
p. 4161 - 4166
(2020/07/13)
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- Denitrative imino-diaza-Nazarov cyclization: Synthesis of pyrazoles
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An iodine-catalyzed denitrative imino-diaza-Nazarov cyclization (DIDAN) methodology has been developed for the synthesis of pyrazoles with high to excellent yields by using α-nitroacetophenone derivatives and in situ generated hydrazones. The key transformation of this oxidative 4π-electrocyclization proceeds through an enamine-iminium ion intermediate. This rapid one-pot DIDAN protocol results in the selective generation of C-C and C-N bonds and cleavage of a C-N bond. This journal is
- Aegurla, Balakrishna,Jarwal, Nisha,Peddinti, Rama Krishna
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p. 6100 - 6107
(2020/10/21)
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- Nickel-catalyzed alkyl-alkyl cross-coupling reactions of non-activated secondary alkyl bromides with aldehydes as alkyl carbanion equivalents
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A novel nickel-catalyzed alkyl-alkyl cross coupling of non-activated secondary alkyl bromides with aldehydes via hydrazone intermediates has been developed. Aldehydes as alkyl carbanion equivalents replace traditional organometallic reagents. This coupling occurs on the carbon of the hydrazone rather than the nitrogen. In addition, non-activated primary and tertiary alkyl bromides also undergo the cross-coupling reaction to form new C(sp3)-C(sp3) bonds in moderate yields.
- Zhu, Chenghao,Zhang, Junliang
-
supporting information
p. 2793 - 2796
(2019/03/06)
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- Denitrogenative Hydrotrifluoromethylation of Benzaldehyde Hydrazones: Synthesis of (2,2,2-Trifluoroethyl)arenes
-
Reacting hydrazones of arylaldehydes with Togni's CF3-benziodoxolone reagent, in the presence of potassium hydroxide and cesium fluoride, induces a denitrogenative hydrotrifluoromethylation event to produce (2,2,2-trifluoroethyl)arenes. This novel reaction was tolerant to many electronically-diverse functional groups and substitution patterns, as well as naphthyl- and heteroaryl-derived substrates. Advantages of this process include the easy access to hydrazone precursors on a large scale, speed and operational simplicity, and being transition metal-free.
- Zhao, Zhensheng,Ma, Kevin C. Y.,Legault, Claude Y.,Murphy, Graham K.
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supporting information
p. 11240 - 11245
(2019/08/20)
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- Umpolung cross-coupling of polyfluoroarenes with hydrazones: Via activation of C-F bonds
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An umpolung strategy for the cross-coupling of polyfluoroarenes with various substituted hydrazones to construct C(sp2)-C(sp3) bonds is developed. In this strategy, the C-F bond of polyfluoroarenes is cleaved and coupled with moisture- and air-stable hydrazones under mild conditions with good to excellent yields. This method provides a useful tool for synthesizing polyfluorinated pharmaceuticals and functional materials.
- Cao, Dawei,Pan, Pan,Zeng, Huiying,Li, Chao-Jun
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supporting information
p. 9323 - 9326
(2019/08/08)
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- Nickel-Catalyzed Regioselective Hydrobenzylation of 1,3-Dienes with Hydrazones
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Hydroalkylation of unsaturated hydrocarbons with unstabilized carbon nucleophiles is difficult and remains a major challenge. The disclosed examples so far have mainly focused on the involvement of heteroatom and/or stabilized carbon nucleophiles as efficient reaction partners. Reported here is an unprecedented regioselective nickel-catalyzed hydrobenzylation of 1,3-dienes with hydrazones, generated in situ from abundant aryl aldehydes and ketones and acting as both the sources of unstabilized carbanion equivalent and hydride. With this strategy, both terminal and sterically hindered internal dienes are hydroalkylated efficiently in a highly selective manner, thus providing a reliable catalytic method to construct challenging C(sp3)-C(sp3) bonds.
- Lv, Leiyang,Zhu, Dianhu,Qiu, Zihang,Li, Jianbin,Li, Chao-Jun
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p. 9199 - 9205
(2019/10/14)
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- Structure-Guided Synthesis and Mechanistic Studies Reveal Sweetspots on Naphthyl Salicyl Hydrazone Scaffold as Non-Nucleosidic Competitive, Reversible Inhibitors of Human Ribonucleotide Reductase
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Ribonucleotide reductase (RR), an established cancer target, is usually inhibited by antimetabolites, which display multiple cross-reactive effects. Recently, we discovered a naphthyl salicyl acyl hydrazone-based inhibitor (NSAH or E-3a) of human RR (hRR) binding at the catalytic site (C-site) and inhibiting hRR reversibly. We herein report the synthesis and biochemical characterization of 25 distinct analogs. We designed each analog through docking to the C-site of hRR based on our 2.7 ? X-ray crystal structure (PDB ID: 5TUS). Broad tolerance to minor structural variations preserving inhibitory potency is observed. E-3f (82% yield) displayed an in vitro IC50 of 5.3 ± 1.8 μM against hRR, making it the most potent in this series. Kinetic assays reveal that E-3a, E-3c, E-3t, and E-3w bind and inhibit hRR through a reversible and competitive mode. Target selectivity toward the R1 subunit of hRR is established, providing a novel way of inhibition of this crucial enzyme.
- Huff, Sarah E.,Mohammed, Faiz Ahmad,Yang, Mu,Agrawal, Prashansa,Pink, John,Harris, Michael E.,Dealwis, Chris G.,Viswanathan, Rajesh
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supporting information
p. 666 - 680
(2018/02/16)
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- Nickel-catalyzed cross-coupling of aldehydes with aryl halides: Via hydrazone intermediates
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Traditional cross-couplings require stoichiometric organometallic reagents. A novel nickel-catalyzed cross-coupling reaction between aldehydes and aryl halides via hydrazone intermediates has been developed, merging the Wolff-Kishner reduction and the classical cross-coupling reactions. Aromatic aldehydes, aryl iodides and aryl bromides are especially effective in this new cross-coupling chemistry.
- Tang, Jianting,Lv, Leiyang,Dai, Xi-Jie,Li, Chen-Chen,Li, Lu,Li, Chao-Jun
-
supporting information
p. 1750 - 1753
(2018/02/21)
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- Cross-Coupling of Phenol Derivatives with Umpolung Aldehydes Catalyzed by Nickel
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A nickel-catalyzed cross-coupling to construct the C(sp2)-C(sp3) bond was developed from two sustainable biomass-based feedstocks: phenol derivatives with umpolung aldehydes. This strategy features the in situ generation of moisture/air-stable hydrazones from naturally abundant aldehydes, which act as alkyl nucleophiles under catalysis to couple with readily available phenol derivatives. The avoidance of using both halides as the electrophiles and organometallic or organoboron reagents (also derived from halides) as the nucleophiles makes this method more sustainable. Water tolerance, great functional group (ketone, ester, free amine, amide, etc.) compatibility, and late-stage elaboration of complex biological molecules exemplified its practicability and unique chemoselectivity over organometallic reagents.
- Lv, Leiyang,Zhu, Dianhu,Tang, Jianting,Qiu, Zihang,Li, Chen-Chen,Gao, Jian,Li, Chao-Jun
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p. 4622 - 4627
(2018/05/22)
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- Iron-Catalyzed Nucleophilic Addition Reaction of Organic Carbanion Equivalents via Hydrazones
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Earth-abundant and well-defined iron complexes are found to be cheap and effective catalysts for a series of "umpolung" nucleophilic additions of hydrazones. The new catalytic system not only maintains the broad substrate scope of an earlier expensive ruthenium system but also attains chemoselectivity of different kinds of carbonyl groups. Furthermore, the iron catalyst enables this reaction at ambient temperature.
- Li, Chen-Chen,Dai, Xi-Jie,Wang, Haining,Zhu, Dianhu,Gao, Jian,Li, Chao-Jun
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supporting information
p. 3801 - 3805
(2018/07/25)
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- Green, Catalyst-Free Reaction of Indoles with β-Fluoro-β-nitrostyrenes in Water
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The reaction of 2-fluoro-2-nitrostyrenes with various indoles was investigated. We found that the reaction proceeds as a Michael addition in a highly regioselective manner to form 3-(1-aryl-2-fluoro-2-nitroethyl)-1H-indoles. Thus, a green and catalyst-free synthesis of these compounds was developed using water as a reaction medium. The high effectiveness of this approach was demonstrated through the preparation of target products in up to 92 % isolated yield. Subsequent reduction of the nitro group was investigated. We found that due to the instability of the intermediate α-fluoro amines, the reduction led to non-fluorinated tryptamine derivatives.
- Aldoshin, Alexander S.,Tabolin, Andrey A.,Ioffe, Sema L.,Nenajdenko, Valentine G.
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p. 3816 - 3825
(2018/07/31)
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- Umpolung of Carbonyl Groups as Alkyl Organometallic Reagent Surrogates for Palladium-Catalyzed Allylic Alkylation
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Palladium-catalyzed allylic alkylation of nonstabilized carbon nucleophiles is difficult and remains a major challenge. Reported here is a highly chemo- and regioselective direct palladium-catalyzed C-allylation of hydrazones, generated from carbonyls, as a source of umpolung unstabilized alkyl carbanions and surrogates of alkyl organometallic reagents. Contrary to classical allylation techniques, this umpolung reaction utilizes hydrazones prepared not only from aryl aldehydes but also from alkyl aldehydes and ketones as renewable feedstocks. This strategy complements the palladium-catalyzed coupling of unstabilized nucleophiles with allylic electrophiles by providing an efficient and selective catalytic alternative to the traditional use of highly reactive alkyl organometallic reagents.
- Zhu, Dianhu,Lv, Leiyang,Li, Chen-Chen,Ung, Sosthene,Gao, Jian,Li, Chao-Jun
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supporting information
p. 16520 - 16524
(2018/11/23)
-
- Solvent-free ring cleavage hydrazinolysis of certain biginelli pyrimidines
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Certain Biginelli pyrimidines with ester substitution in C5 were subjected to unexpected ring opening upon solvent-free reaction with hydrazine hydrate to give three products: pyrazole, arylidenehydrazines, and urea/thiourea, respectively. The nonisolable carbohydrazide intermediates are formed firstly followed by the intermolecular nucleophilic attack of terminal amino group of hydrazide function on sp2 C6 rather than the sp3 C4 to give the ring adduct which was produced as a final product.
- Said, Mohamed A.,Eldehna, Wagdy M.,Ghabbour, Hazem A.,Kabil, Maha M.,Al-shakliah, Nasser S,Abdel-Aziz, Hatem A
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- Aldehydes as alkyl carbanion equivalents for additions to carbonyl compounds
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Nucleophilic addition reactions of organometallic reagents to carbonyl compounds for carbon-carbon bond construction have played a pivotal role in modern chemistry. However, this reaction's reliance on petroleum-derived chemical feedstocks and a stoichiometric quantity of metal have prompted the development of many carbanion equivalents and catalytic metal alternatives. Here, we show that naturally occurring carbonyls can be used as latent alkyl carbanion equivalents for additions to carbonyl compounds, via reductive polarity reversal. Such 'umpolung' reactivity is facilitated by a ruthenium catalyst and diphosphine ligand under mild conditions, delivering synthetically valuable secondary and tertiary alcohols in up to 98% yield. The unique chemoselectivity exhibited by carbonyl-derived carbanion equivalents is demonstrated by their tolerance to protic reaction media and good functional group compatibility. Enantioenriched tertiary alcohols can also be accessed with the aid of chiral ligands, albeit with moderate stereocontrol. Such carbonyl-derived carbanion equivalents are anticipated to find broad utility in chemical bond formation.
- Wang, Haining,Dai, Xi-Jie,Li, Chao-Jun
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p. 374 - 378
(2017/04/03)
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- Carbonyls as Latent Alkyl Carbanions for Conjugate Additions
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Conjugate addition of carbon nucleophiles to electron-deficient olefins is one of the most powerful methods for forming carbon–carbon bonds. Despite great achievements in controlling the selectivity, variation of the carbon nucleophiles remains largely underexplored, with this approach relying mostly on organometallic reagents. Herein, we report that naturally abundant carbonyls can act as latent carbon nucleophiles for conjugate additions through a ruthenium-catalyzed process, with water and nitrogen as innocuous byproducts. The key to our success is homogeneous ruthenium(II) catalysis, combined with phosphines as spectator ligands and hydrazine as the reducing agent. This chemistry allows the incorporation of highly functionalized alkyl fragments into a vast array of electron-deficient olefins under mild reaction conditions in a reaction complementary to the classical organometallic-reagent-based conjugate additions mediated or catalyzed by “soft” transition metals.
- Dai, Xi-Jie,Wang, Haining,Li, Chao-Jun
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supporting information
p. 6302 - 6306
(2017/05/19)
-
- Synthesis of Aryldihalomethanes by Denitrogenative Dihalogenation of Benzaldehyde Hydrazones
-
We report a denitrogenative dihalogenation reaction of phenyldiazomethanes in which the hypervalent iodine reagents PhICl2 and TolIF2 act as surrogates for elemental chlorine and fluorine. Halogen transfer from iodane to aryldiazomethane is described, as is a tandem oxidative dihalogenation reaction between iodane and hydrazone. This is the first use of non-α-stabilized diazo compounds in this reaction, which provided an efficient synthesis of aryldifluoromethane (ArCHF2) and aryldichloromethane (ArCHCl2) derivatives. (Figure presented.).
- Zhao, Zhensheng,Kulkarni, Kaivalya G.,Murphy, Graham K.
-
supporting information
p. 2222 - 2228
(2017/07/07)
-
- The diaza-Nazarov cyclization involving a 2,3-diaza-pentadienyl cation for the synthesis of polysubstituted pyrazoles
-
An unprecedented iodine-mediated diaza-Nazarov (DAN) type cyclization for the construction of substituted pyrazoles from easily available starting materials via an enamine-iminium ion intermediate is described. The oxidative cyclization worked under green conditions with remarkable regioselectivity. This one-pot, efficient and operationally simple three-component intramolecular regioselective DAN cyclization displayed a wide range of substrate scope. The dichotomy of reaction pathways has been explored with density functional theory in the gas phase and solution phase. Of the possible 1,5-, 1,6-, and 1,7-electrocyclizations, the DAN cyclization, i.e., the 1,5-pathway offers the lowest activation energy barrier supporting our experimental observations.
- Aegurla, Balakrishna,Peddinti, Rama Krishna
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p. 9643 - 9652
(2017/11/30)
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- Design and synthesis of novel 3-sulfonylpyrazol-4-amino pyrimidines as potent anaplastic lymphoma kinase (ALK) inhibitors
-
Anaplastic lymphoma kinase (ALK) is a highly attractive therapeutic target for the treatment of some non-small cell lung cancer patients. This Letter describes the further SAR exploration on the novel 3-sulfonylpyrazol-4-amino pyrimidine scaffold. This work identified a compound 53 with very good in vitro/in vivo efficacies, good DMPK properties together with better hERG tolerability and it is currently being profiled for the evaluation as a potential pre-clinical candidate.
- Zhang, Peilong,Dong, Jiaqiang,Zhong, Boyu,Zhang, Deyi,Yuan, Hongbin,Jin, Can,Xu, Xiangyuan,Li, Hailong,Zhou, Yong,Liang, Zhi,Ji, Minghua,Xu, Tao,Song, Guowei,Zhang, Ling,Chen, Gang,Meng, Xuejing,Sun, Desheng,Shih, Joe,Zhang, Ruihao,Hou, Guojun,Wang, Chengcheng,Jin, Ying,Yang, Qiong
-
p. 1910 - 1918
(2016/04/09)
-
- Synthesis of esters by in situ formation and trapping of diazoalkanes
-
A general method has been developed for the in situ formation and trapping of diazoalkanes by carboxylic acids to form esters. The method is applicable to a large variety of carboxylic acids using diazo compounds that are formed from the hydrazones of benzaldehydes and aryl ketones. In situ reaction monitoring with IR spectroscopy (ReactIR) was used to demonstrate that slow addition of the hydrazone to a mixture of oxidant and carboxylic acid avoids the buildup of the diazo compound. This method enables the safe preparation of esters from simple precursors without isolation of diazo compounds.
- Squitieri, Richard A.,Shearn-Nance, Galen P.,Hein, Jason E.,Shaw, Jared T.
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p. 5278 - 5284
(2016/07/14)
-
- Ionic liquids as a reusable media for copper catalysis. Green access to alkenes using catalytic olefination reaction
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It was demonstrated that ionic liquids are superb recyclable media for copper catalyzed reactions using catalytic olefination reaction as an example. As a result a novel green access to the halogenoalkenes was elaborated. Possibility to perform up to five reaction cycles without catalyst leaching and decreasing of the yield was demonstrated. A number of various ionic liquids was screened and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim] [BF4]) was found the solvent with highest efficiency. Mild conditions, high atom economy comparing to other known methods, low amounts of wastes and possibility to recover ionic liquid are the advantages of the proposed method.
- Muzalevskiy, Vasily M.,Shastin, Aleksey V.,Shikhaliev, Namiq G.,Magerramov, Abel M.,Teymurova, Aytekin N.,Nenajdenko, Valentine G.
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p. 7159 - 7163
(2016/10/24)
-
- Facile synthesis of (E)-β-(trifluoromethyl)styrenes from halothane (HCFC-123B1)
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A practical and convenient synthesis of (E)-β-(trifluoromethyl)styrenes has been achieved by the reaction of commercially available halothane (HCFC-123B1) and hydrazones prepared in advance in situ, in the presence of 1,2-ethylenediamine and a catalytic amount of CuCl2·2H2O at room temperature. The products showed acceptable to high yields and high to excellent stereoselectivity. This handy synthetic method provided easy access to a variety of (E)-β-(trifluoromethyl)styrenes.
- Hirotaki, Kensuke,Kawazoe, Genyu,Hanamoto, Takeshi
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p. 169 - 173
(2015/03/04)
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- A novel one pot multi-component strategy for facile synthesis of 5-aryl-[1,2,4]triazolidine-3-thiones
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We have disclosed an efficient, one pot, novel multi-component approach for the synthesis of 5-aryl-[1,2,4]triazolidine-3-thiones from aldehyde, hydrazine hydrate, and trimethylsilyl isothiocyanate (TMSNCS) in the presence of catalytic amount of sulfamic acid. High yields, easy work-up procedure, no chromatographic separation, and novelty in multi-component strategy are the main merits of the present strategy.
- Mane,Pore
-
supporting information
p. 6601 - 6604
(2015/01/09)
-
- Synthesis of 2-aryl-5-oxo-4-[2-(phenylmethylidene)hydrazino]-2,5-dihydro- 1H-pyrrole-3-carboxylates by the reaction between hydrazones, acetylenedicarboxylates, and 1-aryl-N,N′-bis(arylmethylidene) methanediamines
-
An efficient approach for the preparation of functionalized 2-aryl-2,5-dihydro-5-oxo-4-[2-(phenylmethylidene)hydrazino]-1H-pyrroles is described. The four-component reaction between aldehydes, NH2NH 2×H2O, dialkyl acetylenedicarboxylates, and 1-aryl-N,N′-bis(arylmethylidene)methanediamines proceeds in EtOH under reflux in good-to-excellent yields (Scheme 1). The structures of 4 were corroborated spectroscopically (IR, 1H- and 13C-NMR, and EI-MS, and, in the case of 4f, by X-ray crystallography). A plausible mechanism for this type of reaction is proposed (Scheme 2). Copyright
- Alizadeh, Abdolali,Saberi, Vahid,Mokhtari, Javad
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p. 1991 - 1996
(2013/11/06)
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- Proteolytic studies in liver homogenate in presence of substituted aryl hydrazones
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Hydrazones of different arylaldehydes were synthesized and their effect on endogenous proteolysis in liver was studied. It was observed that different functional groups on the benzene moiety altered the enzymatic activity and para-nitrobenzaldehyde hydrazone exhibited maximum inhibitory effect.
- Raghav,Singh, Mamta,Kaur, Ravinder,Suman,Priyanka
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experimental part
p. 1409 - 1410
(2012/01/03)
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- Facile method for the conversion of semicarbazones/thiosemicarbazones into azines (Under Microwave Irradiation) and oxadiazoles (By Grinding)
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In an effective transformation, semicarbazones/thiosemicarbazones are smoothly converted into azines under microwave irradition. Oxadiazoles are also obtained from semicarbazones by reaction with bromine generated in situ via a grinding reaction in the solid phase. Taylor &Francis Group, LLC.
- Chattopadhyay, Gautam,Ray, Partha Sinha
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experimental part
p. 2607 - 2614
(2011/08/07)
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- Novel efficient synthesis of β-fluoro-β-(trifluoromethyl)styrenes
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CF3CFBr2 was employed in catalytic olefination reactions of aromatic aldehydes. In situ prepared hydrazones of aldehydes were transformed to β-fluoro-β-(trifluoromethyl)styrenes by reaction with CF3CFBr2 under CuCl catalysis. Based on this reaction, a novel stereoselective approach towards β-fluoro-β-(trifluoromethyl)styrenes was elaborated. Nucleophilic vinylic substitution of fluorine by secondary amines, thiolates and alkoxides in β-fluoro-β-(trifluoromethyl)styrenes was also tested.
- Goldberg, Aleksey A.,Muzalevskiy, Vasiliy M.,Shastin, Aleksey V.,Balenkova, Elisabeth S.,Nenajdenko, Valentine G.
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experimental part
p. 384 - 388
(2010/04/24)
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- Generation of 2′-deoxyadenosine N6-aminyl radicals from the photolysis of phenylhydrazone derivatives
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Nitrogen-centered radicals are major species generated by the addition of hydroxyl radicals and the one-electron oxidation of adenine derivatives. Aminyl radicals are also generated in the decomposition of adenine chloramines upon reaction of hypochlorite. Here, we report the photochemistry of modified 2′-deoxyadenosine (dAdo) containing photoactive hydrazone substituents as a model to investigate the chemistry of dAdo N6-aminyl radicals. Derivatives of dAdo containing a phenylhydrazone moiety at N6 displayed UV absorption between 300 and 400 nm. Upon UV photolysis in the presence of a H-donor, that is, glutathione, two major products were formed, dAdo and benzaldehyde, indicating efficient homolytic cleavage to dAdo N 6-aminyl radicals and benzylidene iminyl radicals. dAdo N 6-phenylhydrazone was photolyzed in the presence of a molar excess of nonmodified dAdo to mimic the reactions taking place in DNA, and the major photoproducts were identified by high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance. The formation of 2-(benzylideneamino)-2′-deoxyadenosine as well as a more extensive oxidation product may be explained by the recombination of initial dAdo N 6-aminyl and benzylidene iminyl radicals. The formation of 2′-deoxyinosine may be explained by hydrolytic deamination of dAdo N 6-aminyl radicals. Interestingly, a dimeric product containing two dAdo moieties was identified in the photolysis mixture. The present studies demonstrate the ability of dAdo N6-aminyl radicals to undergo H-abstraction to give dAdo, deamination to give 2′-deoxyinosine, and addition to the adenine moiety to give dimers.
- Kuttappan-Nair, Vandana,Samson-Thibault, Francois,Wagner, J. Richard
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experimental part
p. 48 - 54
(2011/01/12)
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- Synthesis and Diels-Alder reactions of α-fluoro- and α-trifluoromethylacrylonitriles
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A novel synthetic method for the preparation of α-fluoro- and the still unknown α-trifluoromethylacrylonitriles is elaborated. The reaction of α-fluorovinylbromides and α-trifluoromethylvinylbromides with CuCN leads to the title compounds in good to high yields. While the α-fluoroacrylonitriles were isolated as mixture of Z/E-isomers, the α-trifluoromethylacrylonitriles were obtained as pure Z-isomers. The α-trifluoromethylacrylonitriles are shown to be excellent dienophiles for Diels-Alder reactions.
- Nenajdenko, Valentine G.,Muzalevskiy, Vasiliy M.,Shastin, Aleksey V.,Balenkova, Elizabeth S.,Haufe, Günter
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p. 818 - 826
(2008/03/14)
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- Reductive deoximation of aryloximes into hydrocarbons by hydrazine/KOH: A novel application of the wolff-kishner reduction
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We report the reductive deoximation of different substituted aryl, diaryl, and aralkyloximes into the respective methyl or methylene derivatives by hydrazine hydrate/KOH at reflux in satisfactory yields. Copyright Taylor & Francis Group, LLC.
- Nanjundaswamy,Pasha
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p. 2183 - 2187
(2007/10/03)
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- A new synthetic approach to α-chlorocinnamaldehydes
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A new simple and efficient transformation of aromatic aldehydes into α-chlorocinnamaldehydes is described. Catalytic olefination reaction of hydrazones of aromatic aldehydes with 2-trichloromethyl-1,3-dioxolane gives ethylene acetals of target alkenes in moderate to good yields. The reaction proceeds stereoselectively to form preferably Z-isomers.
- Nenajdenko, Valentine G.,Reznichenko, Alexander L.,Lenkova, Olesya N.,Shastin, Alexey V.,Balenkova, Elizabeth S.
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p. 605 - 609
(2007/10/03)
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- A new method for the synthesis of cinnamonitriles by catalytic olefination
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Catalytic olefination of hydrazones of aromatic aldehydes with dibromoacetonitrile affords cinnamonitriles.
- Nenajdenko,Golubinskii,Lenkova,Shastin,Balenkova
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p. 252 - 254
(2007/10/03)
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- The catalytic olefination reaction of aldehydes and ketones with CBr 3CF3
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The new approach of catalytic olefination reaction (COR) has been used to convert aromatic and aliphatic aldehydes and ketones to 2-bromo-3,3,3- trifluoroprop-1-enes by the treatment of corresponding hydrazones with CBr 3CF3 under copper(I) catalysis conditions. The reaction proceeds stereoselectively, the target alkenes were obtained in good yields.
- Nenajdenko, Valentine G.,Varseev, Georgy N.,Shastin, Alexey V.,Balenkova, Elisabeth S.
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p. 907 - 913
(2007/10/03)
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- Reaction of CBrF2-CBrF2 with hydrazones of aromatic aldehydes. Novel efficient synthesis of fluorocontaining alkanes, alkenes and alkynes
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An olefination of hydrazones of aromatic aldehydes by CBrF2-CBrF2 under copper catalysis was investigated. In situ prepared aldehydes hydrazones were converted to (3-bromo-2,2,3,3-tetrafluoropropyl)arenes by reaction with CBrF2-CBrF2 in the presence of CuCl. Subsequent elimination of HF by sodium hydroxide resulted in stereospecific formation of fluorocontaining alkenes. Elimination proceeds stereoselectively, only Z -isomers of alkenes are formed. Elimination of two molecules of HF from (3-bromo-2,2,3,3-tetrafluoropropyl)arenes by treatment with potassium tert -butoxide leads to formation of (bromodifluoromethyl)alkynes. As a result a simple and efficient transformation of aromatic aldehydes to range of various fluorinated alkanes, alkenes and alkynes was elaborated.
- Nenajdenko, Valentine G.,Varseev, Georgy N.,Korotchenko, Vasily N.,Shastin, Alexey V.,Balenkova, Elisabeth S.
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p. 1339 - 1345
(2007/10/03)
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- New synthetic approach to α-chlorocinnamates: First example of synthesis of functionally substituted alkenes using catalytic olefination reaction
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A new simple and efficient transformation of carbonyl compounds to α-chlorocinnamates is described. Catalytic olefination reaction with ethyl trichloroacetate gives target alkenes in moderate to good yields. The reaction with aromatic aldehydes proceeds stereoselectively to form preferably Z-isomers.
- Nenajdenko, Valentine G.,Lenkova, Olesya N.,Shastin, Alexey V.,Balenkova, Elizabeth S.
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p. 573 - 577
(2007/10/03)
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- A novel transformation of oximes into hydrazones by hydrazine hydrate
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We report a novel transformation of different substituted aryl, diaryl, and aralkyloximes into the respective hydrazones using hydrazine hydrate in ethanol at reflux in excellent yields.
- Pasha,Nanjundaswamy
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p. 3827 - 3831
(2007/10/03)
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- A novel direct synthesis of (2,2-difluorovinyl)benzenes from aromatic aldehydes
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A novel catalytic approach to (2,2-difluorovinyl)benzenes has been developed. It was found that hydrazones of aromatic aldehydes generated in situ could be converted to the corresponding (2,2-difluorovinyl)benzenes by catalytic olefination reaction (COR) with dibromodifluoromethane in the presence of CuCl.
- Nenajdenko, Valentine G.,Varseev, Georgy N.,Korotchenko, Vasily N.,Shastin, Alexey V.,Balenkova, Elisabeth S.
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p. 115 - 118
(2007/10/03)
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- The Huang-Minlon modification of Wolff-Kishner reduction in rapid and simple way using microwave technology
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A high yielding, simple and fast method for the reduction of various aldehydes and ketones to the respective hydrocarbons following Huang-Minlon modification tender microwave irradiation is described.
- Chattopadhyay, Sarmishtha,Banerjee, Sajal Kumar,Mitra, Alok Kumar
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p. 906 - 907
(2007/10/03)
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- A novel approach to fluoro-containing alkenes
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A new and general one-pot transformation of aromatic aldehydes to fluorinated olefins containing -CH=C(Cl)CF3 or -CH=C(F)CClF2 moieties is described. Freons CCl3CF3 and CCl2FCClF2 were used as trifluoromethyl and difluoromethyl C2-building blocks respectively. A proposed mechanism for the reaction is discussed.
- Korotchenko, Vasily N,Shastin, Alexey V,Nenajdenko, Valentine G,Balenkova, Elisabeth S
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p. 7519 - 7527
(2007/10/03)
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- A novel synthetic approach to dichlorostyrenes
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We found that N-unsubstituted hydrazones of aromatic aldehydes can be easily converted to the corresponding 1,1-dichlorostyrenes in the reaction with carbon tetrachloride using copper (I) chloride as catalyst. Factors affecting the route of the reaction and yields of the products were investigated. A proposed mechanism for the reaction is discussed. (C) 2000 Published by Elsevier Science Ltd.
- Shastin,Korotchenko,Nenajdenko,Balenkova
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p. 6557 - 6563
(2007/10/03)
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- Pyrolysis and Photolysis of 1-Aroylamino-4,5-diaryl-1,2,3-triazoles: Generation and Thermal Transformations of 4,5-Diaryl-1,2,3-triazolyl Radicals
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The pyrolysis of 1-aroylamino-4,5-diphenyl-1,2,3-triazoles 1 yields, pressumably via the 4,5-diphenyl-1,2,3-triazolyl radical (2a), 2,3-diphenyl-2H-azirine (11a) and 2-aryl-4,5-diphenylimidazoles 14 as the major products. Upon irradiation 1-benzoylamino-4,5-diphenyl-1,2,3-triazole (1a) gives 4,5-diphenyl-1(2)H-1,2,3-triazole (4a) via the 1,2,3-triazolyI radical 2a, together with benzamide (5a) and 1,2-bisbenzoylhydrazine (6a). Products 5a and 6a result from the benzoylamino radical 3a by hydrogen atom abstraction and dimerization respectively.
- Hadjiantoniou-Maroulis,Charalambopoulos,Maroulis
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p. 891 - 894
(2007/10/03)
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