- Sequential [3+2] annulation reaction of prop-2-ynylsulfonium salts and hydrazonyl chlorides: Synthesis of pyrazoles containing functional motifs
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A novel sequential [3+2] annulation reaction has been developed using prop-2-ynylsulfonium salts and hydrazonyl chlorides, affording a series of pyrazoles with functional motifs that can be post modified in the preparation of various drugs or drug candidates. Further transformation and gram-scale operations could also be achieved efficiently. This journal is
- Jia, Tingting,Liu, Shourong,Shao, Jiaan,Shi, Tao,Wu, Zhaoxiao,Zeng, Linghui,Zhang, Chong,Zhang, Jiankang,Zhu, Huajian,Zhuang, Rangxiao
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p. 8460 - 8463
(2021/09/08)
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- 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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p. 2359 - 2363
(2021/04/05)
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- Palladium-Catalyzed cascade carbonylative synthesis of 1,2,4-triazol-3-ones from hydrazonoyl chlorides and NaN3
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A palladium-catalyzed three-component carbonylative reaction for the synthesis of 3H-1,2,4-triazol-3-ones from hydrazonoyl chlorides and NaN3 has been achieved. The reaction presumably proceeds through a cascade carbonylation, acyl azide format
- Du, Shiying,Wang, Wei-Feng,Song, Yufei,Chen, Zhengkai,Wu, Xiao-Feng
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supporting information
p. 974 - 978
(2021/02/01)
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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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- 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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p. 2939 - 2943
(2018/05/28)
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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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p. 4714 - 4717
(2017/09/23)
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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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p. 564 - 567
(2016/02/18)
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- Regiospecific Synthesis of N 2-Aryl 1,2,3-Triazoles from 2,5-Disubstituted Tetrazoles via Photochemically Generated Nitrile Imine Intermediates
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The synthesis of N2-aryl 1,2,3-triazoles from 2,5-disubstituted tetrazoles was achieved under photochemical conditions. This simple and mild one-step reaction provides regiospecific access to 2,4,5-substituted 1,2,3-triazoles via a nitrile imine intermediate. Syntheses of alkyl and heterocylic derivatives were also investigated.
- Stewart, Sam,Harris, Robert,Jamieson, Craig
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p. 2480 - 2484
(2015/07/27)
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- Asymmetric catalytic 1,3-dipolar cycloaddition reaction of nitrile imines for the synthesis of chiral spiro-pyrazoline-oxindoles
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A new 1,3-dipolar cycloaddition of nitrile imines with 3-alkenyl-oxindoles was catalyzed by a new chiral Mg(ClO4)2 complex of an N,N'-dioxide ligand. The reaction is so far the sole catalytic synthesis of spiro-pyrazoline-oxindole derivatives. A wide variety of substrates were explored to obtain good yields (up to 98%) and excellent enantioselectivities (up to 99%). This cycloaddition expands the scope of propargyl anion type 1,3-dipole in the construction of 2-pyrazoline subunit.
- Wang, Gang,Liu, Xiaohua,Huang, Tianyu,Kuang, Yulong,Lin, Lili,Feng, Xiaoming
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supporting information
p. 76 - 79
(2013/04/10)
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- Effect of metal ions in organic synthesis. Part XV. Reaction of (arylazo) alkenes and copper(II) chloride in dienophiles or acetone. Synthesis of some N-(α-chlorobenzylidene)-N'-arylhydrazines
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The reaction of (phenylazo) stilbene and copper(II) chloride with some dienophiles produced benzaldehyde and N-(α-chlorobenzylidene)-N'-phenylhydrazine, instead of the expected (4+2)-cycloaddition products.By reaction of some (arylazo) alkenes and copper(
- Attanasi, Orazio,Battistoni, Paolo,Fava, Gabriele
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p. 2665 - 2668
(2007/10/02)
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