- [3+2] cycloadditions: Part XXXV. Selective cycloadditions of C-(4-chlorophenyl)-N-methyl nitrone to cinnamic acid anilides
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[3+2] Cycloadditions of nitrones as three-atom components to alkenes yield isoxazolidine cycloadducts, which on chemical transformations can be converted to bioactive compounds. The [3+2] cycloadditions route thus provides conversion of simple natural pro
- Sengupta, Sumana,Banerji, Avijit,Prangé, Thierry,Neuman, Alain,Hazra, Jayram
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- Regio- and Enantioselective (3+3) Cycloaddition of Nitrones with 2-Indolylmethanols Enabled by Cooperative Organocatalysis
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The regio- and enantioselective (3+3) cycloaddition of nitrones with 2-indolylmethanols was accomplished by the cooperative catalysis of hexafluoroisopropanol (HFIP) and chiral phosphoric acid (CPA). Using this approach, a series of indole-fused six-membered heterocycles were synthesized in high yields (up to 98 %), with excellent enantioselectivities (up to 96 % ee) and exclusive regiospecificity. This approach enabled not only the first organocatalytic asymmetric (3+3) cycloaddition of nitrones but also the first C3-nucleophilic asymmetric (3+3) cycloaddition of 2-indolylmethanols. More importantly, theoretical calculations elucidated the role of the cocatalyst HFIP in helping CPA control the reactivity and enantioselectivity of the reaction, demonstrating a new mode of cooperative catalysis.
- Li, Tian-Zhen,Liu, Si-Jia,Sun, Yu-Wen,Deng, Shuang,Tan, Wei,Jiao, Yinchun,Zhang, Yu-Chen,Shi, Feng
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supporting information
p. 2355 - 2363
(2020/12/09)
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- Carbamoylation of Azomethine Imines via Visible-Light Photoredox Catalysis
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A versatile and robust photocatalytic methodology to install the amide functional group into azomethine imine ions is described. This protocol is distinguished by its broad scope and mild reaction conditions, which are well suited for the preparation of s
- Correia, José Tiago M.,Matsuo, Bianca T.,Oliveira, Pedro H. R.,Paix?o, Márcio W.
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supporting information
p. 6775 - 6779
(2021/09/13)
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- A green synthesis of nitrones in glycerol
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Abstract: An eco-friendly and efficient synthesis of nitrones is presented by condensation of an equimolar amount of aldehydes and N-substituted hydroxylamine hydrochlorides in glycerol as a recyclable solvent-catalyst. This novel protocol provides rapid and mild access to a series of nitrone derivatives in good to excellent yields in the absence of catalyst and base. Graphic abstract: SYNOPSIS In this study, a base-free protocol by using glycerol as the solvent-catalyst was applied for an eco-friendly synthesis of nitrones from the condensation of aldehydes and N-substituted hydroxylaminehydrochlorides.[Figure not available: see fulltext.].
- Shariatipour, Monire,Jadidinejad, Masoumeh,Heydari, Akbar
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- A highly diastereoselective [3+3] annulation reaction of aza-oxyallyl cations and nitrones
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An efficient synthesis of 1,2,4-oxadiazinan-5-ones via [3+3] cycloaddition of in situ generated aza-oxyallyl cations with nitrones has been developed. The protocol features easy operation, excellent yields, excellent diastereo-control, broad substrate sco
- Chen, Rongxing,Sun, Shaofa,Wang, Gangqiang,Guo, Haibin
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supporting information
p. 1916 - 1920
(2018/04/19)
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- One-Pot Sequential [3 + 3] Dipolar Cycloaddition of Aldehyde or Ketone and Hydroxylamine with Spirocyclopropyl Oxindole
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A Sc(OTf)3-catalyzed highly diastereoselective one-pot sequential [3 + 3] dipolar cycloaddition reaction of aldehyde or ketone, N-alkyl hydroxylamine, and spirocyclopropyl oxindole is developed, allowing facile construction of spirocyclic oxind
- Xu, Peng-Wei,Chen, Chen,Liu, Jia-Kuan,Song, Yu-Ting,Zhou, Feng,Yan, Jun,Zhou, Jian
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p. 12763 - 12774
(2018/10/20)
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- Crystal and molecular structure studies of (Z)-N-methyl-C-4-substituted phenyl nitrones by XRD, DFT, FTIR and NMR methods
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(Z)-N-methyl-C-4-substituted phenyl nitrones –O+N(Me)=C(H)R (Z-2a R = 4-ClC6H4, Z-2b R = 4-NO2C6H4, Z-2c R = 4-CH3OC6H4) were synthesized and cha
- Lasri, Jamal,Eltayeb, Naser Eltaher,Haukka, Matti,Alghamdi, Yousef
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- Cooperative Multifunctional Catalysts for Nitrone Synthesis: Platinum Nanoclusters in Amine-Functionalized Metal–Organic Frameworks
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Nitrones are key intermediates in organic synthesis and the pharmaceutical industry. The heterogeneous synthesis of nitrones with multifunctional catalysts is extremely attractive but rarely explored. Herein, we report ultrasmall platinum nanoclusters (PtNCs) encapsulated in amine-functionalized Zr metal–organic framework (MOF), UiO-66-NH2 (Pt@UiO-66-NH2) as a multifunctional catalyst in the one-pot tandem synthesis of nitrones. By virtue of the cooperative interplay among the selective hydrogenation activity provided by the ultrasmall PtNCs and Lewis acidity/basicity/nanoconfinement endowed by UiO-66-NH2, Pt@UiO-66-NH2 exhibits remarkable activity and selectivity, in comparison to Pt/carbon, Pt@UiO-66, and Pd@UiO-66-NH2. Pt@UiO-66-NH2 also outperforms Pt nanoparticles supported on the external surface of the same MOF (Pt/UiO-66-NH2). To our knowledge, this work demonstrates the first examples of one-pot synthesis of nitrones using recyclable multifunctional heterogeneous catalysts.
- Li, Xinle,Zhang, Biying,Tang, Linlin,Goh, Tian Wei,Qi, Shuyan,Volkov, Alexander,Pei, Yuchen,Qi, Zhiyuan,Tsung, Chia-Kuang,Stanley, Levi,Huang, Wenyu
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supporting information
p. 16371 - 16375
(2017/11/28)
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- Synthesis and application of phenyl Nitrone derivatives as acidic and microbial corrosion inhibitors
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Nitrone has drawn great attention due to its wide applications as a 1,3-dipole in heterocyclic compounds synthesis and the bioactivities. With the special structure, nitrone can also be used as ligand in inorganic chemistry. Based on the current research,
- Chen, Shijun,Zhao, Kang,Chen, Gang
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- A magnetoclick imidazolidinone nanocatalyst for asymmetric 1,3-dipolar cycloadditions
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A 1,3-dipolar azide-alkyne cycloaddition has been used to prepare a magnetic nanoparticle immobilized MacMillan catalyst that catalyzes the enantioselective 1,3-dipolar cycloaddition between nitrones and α,β-unsaturated aldehydes. The catalyst can be recovered and recycled for five consecutive runs without any significant loss in yields and diastereo- and enantioselectivities of the isoxazolidines. Copyright
- Pagoti, Sreenivasarao,Dutta, Debasish,Dash, Jyotirmayee
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supporting information
p. 3532 - 3538
(2014/01/06)
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- Methyltrioxorhenium-catalysed oxidation of secondary amines to nitrones in ionic liquids
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Nitrones serve as starting materials for the synthesis of many heterocycles. Oxidation of secondary amines using hydrogen peroxide and the catalytic amount of methyltrioxorhenium in ionic liquids is a useful method for the preparation of nitrones. Ultrasonic irradiation and ionic liquids have a positive influence on the reaction. The nitrones required were isolated in good yields. Corresponding hydroxylamines, which can be easily oxidised to nitrones, often accompanied the main products. Methyltrioxorhenium in ionic liquids was re-used in several reaction cycles without any deteriorating effect on the course of the reaction.
- Meciarova, Maria,Mojzesova, Melinda,Sebesta, Radovan
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p. 51 - 58,8
(2020/08/20)
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- DFT study of 1,3-dipolar cycloadditions of C,N-disubstituted aldonitrones to chalcones evidenced by NMR and X-ray analysis
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A DFT/B3LYP/6-31G*study was carried out to predict the regio- and stereoselectivities of 1,3-dipolar cycloadditions of C,N-disubstituted aldonitrones to chalcones in terms of FMO theory, DFT-based reactivity indices, and activation energy calculations. Th
- Acharjee, Nivedita,Banerji, Avijit,Prange, Thierry
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body text
p. 1213 - 1221
(2011/09/12)
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- FUNGICIDAL ISOXAZOLIDINES
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Disclosed are compounds of Formula 1, including all geometric and stereoisomers, N-oxides, and salts thereof, wherein A, B, D, R1, R2, R3, X and m are as defined in the disclosure. Also disclosed are compositions containin
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Page/Page column 17
(2009/10/31)
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- 1,3-Dipolar cycloadditions. Part-XV: Systematic spectroscopic investigations of C-aryl-N-methylnitrones
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Several C-aryl-N-methylnitrones have been synthesised during the course of our work on 1,3-dipolar cycloadditions. Detailed systematic spectroscopic investigations of all these nitrones have been undertaken. These are reported along with some generalisati
- Banerji, Avijit,Acharjee, Nivedita,Biswas, Pizush Kanti
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scheme or table
p. 63 - 67
(2010/05/02)
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- N-tert-Butyl and N-methyl nitrones derived from aromatic aldehydes inhibit macromolecular permeability increase induced by ischemia/reperfusion in hamsters
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N-Alquil nitrones 1c and 3-6 were prepared from aromatic aldehydes and N-tert-butylhydroxylamine or N-methylhydroxylamine in good yields and soft conditions. Their protective effect against microvascular damages caused by ischemia/reperfusion in 'hamster
- Dias, Ayres G.,Santos, Carlos E.V.,Cyrino, Fatima Z.G.A.,Bouskela, Eliete,Costa, Paulo R.R.
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experimental part
p. 3995 - 3998
(2009/10/17)
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- 1,3-Dipolar cycloadditions. Part XVII: Experimental and theoretical spectroscopic investigations of C-aryl-N-methyl nitrones
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Detailed experimental and theoretical spectroscopic studies of C-aryl-N-methyl nitrones have been reported. The optimized geometries have been calculated by DFT/B3LYP level of theory with 6-31+G(d,p) basis set. The theoretically computed frontier orbital
- Acharjee, Nivedita,Banerji, Avijit,Banerjee, Manas,Das, Tapas K.
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body text
p. 1627 - 1637
(2010/06/17)
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- Exploiting microwave-assisted neat procedures: synthesis of N-aryl and N-alkylnitrones and their cycloaddition en route for isoxazolidines
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Microwave irradiation allows increasing the speed of several reactions and also offers the possibility of eliminating poisoning organic solvents. In this work we report the microwave-assisted neat synthesis of α-phenyl-tert-butylnitrone (PBN) and other alkyl and aryl nitrones and also the rapid synthesis of isoxazolidines resulting from 1,3-dipolar cycloaddition of nitrones to ethyl trans-crotonate.
- Andrade, Marta M.,Barros, Maria Teresa,Pinto, Rui C.
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p. 10521 - 10530
(2008/12/23)
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- 1,3-Dipolar cycloadditions: Part VIII1-Microwave irradiation assisted synthesis of N-methyl-C-aryl nitrones
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N-Methyl-C-arylnitrones have been synthesized in very high yields within a few minutes from N-methyl-hydroxylamine hydrochloride and aryl aldehydes in presence of sodium hydrogen carbonate in methylene chloride using the microwave irradiation technique.
- Banerji, Avijit,Biswas, Pizush Kanti,Sengupta, Piyali,Dasgupta, Saugandha,Gupta, Maya
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p. 880 - 881
(2007/10/03)
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- A facile and new method for the synthesis of α-aryl-N-methylnitrones in solvent-free media using silica gel-NaOH
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Substituted α-aryl-N-methylnitrones are prepared by the condensation reaction of N-methylhydroxylamine hydrochloride and benzaldehydes in solvent-free media using silica-gel-NaOH catalyst system. The yields are excellent regardless of the electron-donatin
- Alavi Nikje,Bigdeli,Imanieh
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p. 1465 - 1468
(2007/10/03)
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- Oxidation of secondary amines by molecular oxygen and cyclohexanone monooxygenase
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Cyclohexanone monooxygenase from Acinetobacter calcoaceticus catalyzed the oxidation of tertiary and secondary amines to N-oxides and nitrones, respectively. The formation of a hydroxylamine intermediate was involved with secondary amines as starting substrates.
- Colonna, Stefano,Pironti, Vincenza,Carrea, Giacomo,Pasta, Piero,Zambianchi, Francesca
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p. 569 - 575
(2007/10/03)
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- An efficient and rapid chemoselective synthesis of α-Aryl-N-methylnitrones in dry media
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A simple, efficient, and eco-friendly procedure was developed for the condensation of N-methylhydroxylamine hydrochloride with benzaldehydes bearing electron-donating or electron-withdrawing substituents in the presence of powdered molecular sieves (3 A)
- Bigdeli,Nikje
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p. 1547 - 1549
(2007/10/03)
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- Oxidation of N-benzyl-N-methylhydroxylamines to nitrones. A mechanistic study
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Oxidation of various N-(o-, m-, p- substituted benzyl)- N-methylhydroxylamines has been carried out using mercury(II) oxide and p-benzoquinone (p-BQ) as oxidants. Hammett plots have been obtained with negative ρ values, showing the development of a positive centre in the transition state. The unstable E nitrones, which readily isomerize to the more stable Z nitrones, are obtained in appreciable quantities and in some cases as the major product. A considerable deuterium isotope effect is observed in the oxidation process. The overall picture of the mechanistic pathway involves electron transfer from nitrogen to the oxidant followed by hydrogen abstraction.
- Hassan, Azfar,Wazeer, Mohammed I. M.,Ali, Sk. Asrof
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p. 393 - 399
(2007/10/03)
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- Chromium and Tungsten Pentacarbonyl Groups as Reactivity and Selectivity Auxiliaries in Cycloaddition of Alkynyl Fischer Carbene Complexes with N-Alkyl Nitrones
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Alkynyl Fischer carbene complexes were found to undergo chemoselective, regioselective, and rate-enhanced 1,3-dipolar cycloaddition with nitrones to give 2,3-dihydroisoxazole carbene complexes in excellent yields.These alkynyl complexes can serve as synth
- Chan, Kin Shing,Yeung, Ming Lok,Chan, Wai-kin,Wang, Ru-Ji,Mak, Thomas C. W.
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p. 1741 - 1747
(2007/10/02)
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