- Synthesis of 3 H-1,2,4-Triazol-3-ones via NiCl2-Promoted Cascade Annulation of Hydrazonoyl Chlorides and Sodium Cyanate
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A nickel-promoted cascade annulation reaction for the facile synthesis of 3H-1,2,4-triazol-3-ones from readily available hydrazonoyl chlorides and sodium cyanate has been developed. The transformation occurs through a cascade nickel-promoted intermolecular nucleophilic addition-elimination process, intramolecular nucleophilic addition, and a hydrogen-transfer sequence. The method has been successfully applied for the construction of the core skeleton of the angiotensin II antagonist.
- Du, Shiying,Yang, Zuguang,Tang, Jianhua,Chen, Zhengkai,Wu, Xiao-Feng
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supporting information
p. 2359 - 2363
(2021/04/05)
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- An Efficient Catalytic Amidation of Esters Promoted by N-Heterocyclic Carbenes
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An efficient NHC-catalyzed amidation between esters and amines or hydrazines is described. This strategy was tolerant for a wide scope of substrates, affording a series of amides (or hydrazides) in good to excellent yields (60-96%) under simple conditions. The approach was also used to synthesize the pharmaceutically relevant antidepressant moclobemide in 85% yield.
- Chen, Ling-Yan,Wu, Mei-Fang
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p. 1595 - 1602
(2019/03/26)
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- A [4 + 3] Annulation Reaction of aza- o-Quinone Methides with Arylcarbohydrazonoyl Chlorides for Synthesis of 2,3-Dihydro-1 H-benzo[ e][1,2,4]triazepines
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An unprecedented [4 + 3] annulation reaction of aza-ortho-quinone methides with arylcarbohydrazonoyl chlorides has been achieved under mild conditions. The annulation underwent a sequential conjugate addition/intramolecular annulation/rearrangement, providing a useful method for the synthesis of biologically interesting 2,3-dihydro-1H-benzo[e][1,2,4]triazepine.
- Guo, Zhenyan,Jia, Hao,Liu, Honglei,Wang, Qijun,Huang, Jiaxing,Guo, Hongchao
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supporting information
p. 2939 - 2943
(2018/05/28)
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- [3+2]-cycloaddition of in situ generated nitrile imines and acetylene for assembling of 1,3-disubstituted pyrazoles with quantitative deuterium labeling
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A novel synthetic methodology for the preparation of 1,3-disubstituted pyrazoles from in situ generated nitrile imines and acetylene is reported. The reactions are performed in a simple two-chamber reactor. One part of the reactor is loaded with hydrazonoyl chloride precursors of active nitrile imine species and a base. The other part is used to generate acetylene from CaC2 and water. Partitioning of the reactants improves the yields of desired pyrazoles up to 99% and simplifies their isolation to a simple procedure of solvent evaporation. The approach requires no complex equipment and utilizes inexpensive, safe, and easy to handle calcium carbide as a starting material. A model deuterium incorporation is carried out according to the developed methodology, producing a series of novel 4,5-dideuteropyrazoles with excellent deuterium enrichment. Theoretical calculations on reaction mechanism and characterization of possible intermediate structures were performed.
- Voronin, Vladimir V.,Ledovskaya, Maria S.,Gordeev, Evgeniy G.,Rodygin, Konstantin S.,Ananikov, Valentine P.
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p. 3819 - 3828
(2018/04/14)
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- Synthesis of Spirobidihydropyrazole through Double 1,3-Dipolar Cycloaddition of Nitrilimines with Allenoates
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The double 1,3-dipolar cycloaddition of allenoates with nitrilimines has been achieved under mild reaction conditions, affording a variety of spirobidihydropyrazoles in moderate to excellent yields with excellent diastereoselectivities. The reaction diastereoselectively constructs double dihydropyrazole moieties and two chiral centers including a spiro carbon center.
- Liu, Honglei,Jia, Hao,Wang, Bo,Xiao, Yumei,Guo, Hongchao
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supporting information
p. 4714 - 4717
(2017/09/23)
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- Easy and rapid preparation of benzoylhydrazides and their diazene derivatives as inhibitors of 15-lipoxygenase
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Two series of diaza derivatives were prepared by solvent-free condensation of benzoic acid and 4-substituted phenylhydrazines in order to obtain phenylhydrazides (HYD series) and, by oxidation of these compounds, the corresponding benzoyldiazenes (DIA series). Both sets were evaluated as inhibitors of soybean 15-lipoxygenase activity and antioxidant capability in the FRAP and CUPRAC assays. The most potent inhibitors of both series exhibited IC50 values in the low micromolar range. Kinetic studies showed that at least the more active compounds were competitive inhibitors. Docking results indicated that the most potent inhibitor interacts strongly with Ile-839 and iron in the active site.
- Tirapegui, Cristian,Acevedo-Fuentes, Williams,Dahech, Pablo,Torrent, Claudia,Barrias, Pablo,Rojas-Poblete, Macarena,Mascayano, Carolina
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supporting information
p. 1649 - 1653
(2017/04/04)
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- [3+3]-cycloaddition of donor-acceptor cyclopropanes with nitrile imines generated in situ: Access to tetrahydropyridazines
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Donor-acceptor cyclopropanes are reacted under the influence of a Lewis acid with hydrazonyl chlorides to afford tetrahydropyridazines. Formally, this transformation can be regarded as a [3 + 3]-cycloaddition of three-membered rings and nitrile imines generated in situ. This efficient method provides fast access to a variety of structurally diverse pyridazine derivatives. The structure of a typical product was confirmed by X-ray crystallography.
- Garve, Lennart K. B.,Petzold, Martin,Jones, Peter G.,Werz, Daniel B.
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supporting information
p. 564 - 567
(2016/02/18)
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- Copper(ii)-catalyzed coupling reaction: An efficient and regioselective approach to N′,N′-diaryl acylhydrazines
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Using N′-aryl acylhydrazines as aryl donors, a novel copper(ii)-catalyzed homo-coupling reaction of N′-aryl acylhydrazines has been developed for the synthesis of N′,N′-diaryl acylhydrazines. We also provided a complementary procedure for the preparation of unsymmetrical diaryl acylhydrazines via cross-coupling reaction. These protocols featured mild reaction conditions, wide functional group tolerance and highly regioselective products. Control experiments indicated that this kind of coupling reaction might undergo a transient acyl diazene intermediate. This journal is
- Zhang, Ji-Quan,Huang, Gong-Bin,Weng, Jiang,Lu, Gui,Chan, Albert S. C.
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supporting information
p. 2055 - 2063
(2015/03/05)
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- KOt-Bu promoted homocoupling and decomposition of N'-aryl acylhydrazines: synthesis of unsymmetric N',N'-diaryl acylhydrazines
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The KOt-Bu promoted homocoupling and decomposition of N'-aryl acylhydrazines has been achieved. The method allows for a novel and efficient synthesis of unsymmetric N',N'-diaryl acylhydrazines under mild reaction conditions. The reaction probably proceeds via the generation of N'-centered acylhydrazine radicals and the subsequent homolytic aromatic substitution.
- Wang, Wei-Juan,Zhang, Ting,Duan, Li-Jun,Zhang, Xue-Jing,Yan, Ming
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p. 9073 - 9080
(2015/11/09)
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- 1,3-Diarylcycloalkanopyrazoles and diphenyl hydrazides as selective inhibitors of cyclooxygenase-2
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Novel 1,3-diarylcycloalkanopyrazoles 1, and diphenyl hydrazides 2 were identified as selective inhibitors of cyclooxygenase-2. The 1,3-diaryl substitution pattern of the pyrazole ring in 1 differentiates these compounds from most of the known selective COX-2 inhibitors that contain two aryl rings at the adjacent positions on a heterocyclic or a phenyl ring. Similarly, the two phenyl rings in 2 are also separated by three atoms. SAR of both phenyl rings in 1 and 2, and the aliphatic ring in 1 will be discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.
- Sui, Zhihua,Guan, Jihua,Ferro, Michael P.,McCoy, Kathy,Wachter, Michael P.,Murray, William V.,Singer, Monica,Steber, Michele,Ritchie, Dave M.,Argentieri, Dennis C.
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p. 601 - 604
(2007/10/03)
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- Addition of Semidione Radicals to Arenediazonium Ions: Synthesis of 1,1-Diacyl-2-arylhydrazines
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The α-dicarbonyl compounds 1 are selectively reduced to semidione radicals 2 by aqueous Ti3+, via inner-sphere electron transfer (ET).When an equimolar amount of an arenediazonium salt (3) is present, 2 adds to the nitrogen-nitrogen triple bond of 3 to afford the intermediate azo radical cation C, which, depending on the nature of the para substituent of the N-phenyl ring, undergoes rearrangement to a 1,1-diacyl-2-arylhydrazine (4) or preferentially reduction to a hydrazone (5).A mechanism that accounts for both the rearrangement and the substituent effects that are observed is proposed.
- Clerici, Angelo,Porta, Ombretta
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p. 6813 - 6818
(2007/10/02)
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- Acylation Reactions of Phenylhydrazines. Preparation and Properties of New Diacylphenylhydrazines
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Anhydride acylation reactions of a variety of substituted arylhydrazines under mild conditions led to controlled formation of the acid phenylhydrazides I (Table I).The procedures were tallored to the particular state of the starting arylhydrazine.Second-s
- Hearn, Michael J.,Magee, Debra J.,Alhart, Randi,Gleva, Marye,Goldstein, Susan,et al.
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p. 129 - 131
(2007/10/02)
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