100-10-7Relevant articles and documents
Organocatalyzed and uncatalyzed C=C/C=C and C=C/C=N exchange processes between knoevenagel and imine compounds in dynamic covalent chemistry
Kulchat, Sirinan,Meguellati, Kamel,Lehn, Jean-Marie
, p. 1219 - 1236 (2014)
Molecular diversity generation through reversible component exchange has acquired great importance in the last decade with the development of dynamic covalent chemistry. We explore here the recombination of components linked by C=C and C=N bonds through reversible double-bond formation, and cleavage in C=C/C=C and C=C/C=N exchange processes. The reversibility of the Knoevenagel reaction has been explored, and C=C/C=C C/C exchanges have been achieved among different benzylidenes, under organocatalysis by secondary amines such as L-proline. The substituents of these benzylidenes were shown to play a very important role in the kinetics of the exchange reactions. L-Proline is also used to catalyze the reversible C=C/C=C exchange between Knoevenagel derivatives of barbituric acid and malononitrile. Finally, the interconversion between Knoevenagel derivatives of dimethylbarbituric acid and imines (C=C/C=N exchange) has been studied and was found to occur rapidly in the absence of catalyst. The results of this study pave the way for the extension of dynamic combinatorial chemistry based on C=C/C=C and C=C/C=N exchange systems.
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Splitter,J.S.,Calvin,M.
, p. 1445 - 1448 (1968)
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Cobalt-catalysed selective synthesis of aldehydes and alcohols from esters
Pattanaik, Sandip,Gunanathan, Chidambaram
, p. 7345 - 7348 (2020)
Efficient and selective reduction of esters to aldehydes and alcohols is reported in which a simple cobalt pincer catalyst catalyses both transformations using diethylsilane as a reductant. Remarkably, the reaction selectivity is controlled by the stoichiometry of diethylsilane. This journal is
Selective conversion of C=N bonds to their corresponding carbonyl compounds by the tribromoisocyanuric acid/wet SiO2 system as a novel reagent
Habibi, Davood,Zolfigol, Mohammad Ali,Faraji, Ali Reza,Rahmani, Payam
, p. 809 - 814 (2012)
Tribromoisocyanuric acid/wet SiO2 was used for the conversion of C=N bonds to their corresponding carbonyl compounds in oximes, semicarbazones, azines, and Schiff bases. The interesting feature of this system is that in those oximes, semicarbazones, azines, and Schiff bases which have conjugated or unconjugated C=C bonds, the C=N bond will selectively change to the relevant C=O bond while the conjugated or unconjugated C=C bond will remain intact. Springer-Verlag 2011.
Vilsmeier-Haack synthesis of aromatic aldehydes using bis-(trichloromethyl) carbonate and dimethylformamide
Shan,Shi,Su
, p. 337 - 340 (2004)
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Kinetics of Hydrolysis of Some N'-(4-Substituted Benzylidene)salicylohydrazides
Temerk, Yassien M.,Kamal, Mostafa M.,Ahmed, Mohamed E.
, p. 337 - 340 (1984)
The rates of hydrolysis of a series of substituted benzylidenesalicylohydrazide derivatives 40percent (v/v) ethanol-buffer mixture have been investigated by differential pulse polarography.The hydrolysis is catalysed by H+ and its rate follows strictly first-order kinetics.The rate constant decreases with increasing pH up to around pH 3.9, beyond which no measurable reaction was observed; here the protonation of imine begins to be significantly incomplete.The attack of water on the protonated substrate is considered to be the rate-determining step.The effects of pH, molecular structure, and temperature on the reaction rate and the activation energy are reported.Thermodynamic parameters (ΔG(formula), ΔH(formula), and ΔS(fomula)) for the hydrolysis are discussed.
A convenient method for in situ generation of I2 using CuSO 4/NaI and its applications to the deprotection of acetals, etherifications and iodolactonizations
Bailey, Aaron D.,Cherney, Steven M.,Anzalone, Peter W.,Anderson, Erin D.,Ernat, Justin J.,Mohan, Ram S.
, p. 215 - 218 (2006)
A convenient method for the in situ generation of I2 using CuSO4/NaI has been developed. The applications of this method to the deprotection of acetals, etherifications and iodolactonizations have been demonstrated. The use of toxic and corrosive molecular iodine is avoided. Georg Thieme Verlag Stuttgart.
Deprotection of oximes, imines, and azines to the corresponding carbonyls using Cu-nanoparticles on cellulose template as green reusable catalyst
Baruah, Diganta,Saikia, Ujwal Pratim,Pahari, Pallab,Dutta, Dipak Kumar,Konwar, Dilip
, p. 59338 - 59343 (2014)
The deprotection of wide varieties of oximes, imines, and azines to their corresponding carbonyls has been achieved using Cu-nanoparticles on a cellulose template as a reusable catalyst. The reactions were carried out at 80-100 °C using microwave irradiation in water under neutral condition. The catalyst can be reused for several cycles with good to excellent yield.
Gold nanoparticles supported on ionic liquid-modified cellulose as an efficient and recyclable catalyst for the oxidation of alcohols to aldehydes/ketones and reduction of nitroarenes
Pourjavadi, Ali,Habibi, Zahra
, (2017)
A novel catalyst of gold nanoparticles supported on cellulose fibres with the ionic liquid framework (Au NPs@CL-IL) has been shown to be a highly active and recyclable catalyst for the oxidation of primary and secondary alcohols and reduction of nitroaren
Nanorods of FeVO4: An efficient heterogeneous catalyst for chemoselective oxidation of benzylic alcohols
Heydari, Akbar,Sheykhan, Mehdi,Sadeghi, Masoud,Radfar, Iman
, p. 248 - 255 (2017)
Controllable fabrication of iron vanadate (FeVO4) was achieved by the hydrothermal approach. The excellent catalytic activity of the prepared nanorods of iron vanadate for the oxidation of benzylic alcohols as well as its potential for oxidation of the benzylic sp3 C-Hs in the presence of urea hydrogen peroxide (UHP) as oxidant was reported. The prepared nanorods and nanospheres were fully characterized by FT-IR, XRD, EDAX, ICP-AES, SEM, and TEM. In the presence of the catalyst, alcohols chemoselectively (100%) convert to the corresponding aldehydes/ketones, giving a total turnover number about 380 for 10 consecutive runs.
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Fleet,Little
, p. 3749 (1977)
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Cobalt tungsten oxide hydroxide hydrate (CTOHH) on DNA scaffold: An excellent bi-functional catalyst for oxygen evolution reaction (OER) and aromatic alcohol oxidation
Kumaravel, Sangeetha,Thiruvengetam, Prabaharan,Ede, Sivasankara Rao,Karthick,Anantharaj,Sam Sankar, Selvasundarasekar,Kundu, Subrata
, p. 17117 - 17131 (2019)
A material with interdisciplinary properties is of wide interest for use in environmental applications. Currently, hydrogen generation by electrolysis and formation of carbonyl derivatives from alcohols are two different fields that focus on energy and environmental applications. In this work, a new material, Cobalt Tungsten Oxide Hydroxide Hydrate (CTOHH) on deoxyribonucleic acid (DNA) scaffold having chain-like morphology has been prepared for the first time by a facile microwave heating method. The same CTOHH was also prepared without the DNA scaffold and resulted in irregular aggregated molecular structures. Further, both CTOHH-DNA and CTOHH were converted into CoWO4-DNA and CoWO4, respectively by annealing them at a temperature of 600 °C. All the four catalysts were used for electrocatalytic oxygen evolution reaction (OER) and for oxidation of aromatic alcohols. In OER, CTOHH-DNA delivered fruitful results compared to all other electrocatalysts. For attaining a current density of 10 mA cm-2, it just required an overpotential of 355 mV with a Tafel slope value of 47.5 mV dec-1. Similarly, all four catalysts were also analyzed for selective and controlled oxidation of aromatic alcohols to their respective aldehydes and ketones using molecular oxygen as a green oxidant where CTOHH-DNA showed better results. Chemo-selectivity has been observed for CTOHH-DNA in the co-presence of hydroxyl and cyano functional groups. The durability of CTOHH-DNA was analyzed and it showed excellent catalytic activity retention up to five cycles.
Catalytic oxidation of primary aromatic alcohols using half sandwich Ir(III), Rh(III) and Ru(II) complexes: A practical and theoretical study
Thangavel, Saravanan,Boopathi, Subramaniam,Mahadevaiah,Kolandaivel, Ponmalai,Pansuriya, Pramod B.,Friedrich, Holger B.
, p. 160 - 171 (2016)
The complexes [Cp*IrCl(N-(pyridin-2-ylmethylene)aniline)]PF6 (1), [Cp*RhCl(N-(pyridin-2-ylmethylene)aniline)]PF6 (2), (where Cp*?=?1,2,3,4,5-pentamethylcyclopentadiene) and [η6-areneRuCl(N-(pyridin-2-ylmethylene)aniline)]PF6 (3) have been synthesized and the structure and purity of these were confirmed by single crystal XRD and elemental analyses. Iridium and rhodium complexes exhibit the P21/n space group, the ruthenium complex the P21/c space group and all three complexes show the expected pseudo octahedral “piano-stool” geometry. The catalytic performance of these complexes for the dehydrogenation of primary alcohols to their respective aldehydes with different bases and solvents was investigated. The complexes of iridium and ruthenium give good conversions in different alkaline solutions. Density functional theory was applied to determine the respective MO energy levels, bond lengths, bond angles and binding energies of all the metal complexes. It was also used to study the activity, stability and intermediates of the complexes. A Gibbs free energy (ΔG) DFT calculation was carried out to help understand the reaction mechanism/catalytic cycle of the Rh complex (2). The energy barrier for oxidation of aromatic alcohols by the rhodium hydride complex is much lower (10.32?kcal/mol) than the barrier for hydride transfer of the corresponding Rh benzyloxo species (15.19?kcal/mol), in agreement with mechanisms proposed for related systems.
A Magnetically Recyclable Palladium-Catalyzed Formylation of Aryl Iodides with Formic Acid as CO Source: A Practical Access to Aromatic Aldehydes
You, Shengyong,Zhang, Rongli,Cai, Mingzhong
, p. 1962 - 1970 (2021)
A magnetically recyclable palladium-catalyzed formylation of aryl iodides under CO gas-free conditions has been developed by using a bidentate phosphine ligand-modified magnetic nanoparticles-anchored- palladium(II) complex [2P-Fe 3O 4@SiO 2-Pd(OAc) 2] as catalyst, yielding a wide variety of aromatic aldehydes in moderate to excellent yields. Here, formic acid was employed as both the CO source and the hydrogen donor with iodine and PPh 3as the activators. This immobilized palladium catalyst can be obtained via a simple preparative procedure and can be facilely recovered simply by using an external magnetic field, and reused at least 9 times without any apparent loss of catalytic activity.
Organocatalysis of c?￡/c?￡N and C?￡C/ C?￡N exchange in dynamic covalent chemistry
Wilhelms, Nadine,Kulchat, Sirinan,Lehn, Jean-Marie
, p. 2635 - 2651 (2012)
The reversibly formed C?￡N bond plays a very important role in dynamic covalent chemistry and the C?￡N/C?￡N exchange of components between different imine constituents to create dynamic covalent libraries has been extensively used. To facilitate diversity generation, we have investigated an organocatalyzed approach, using L-proline as catalyst, to accelerate the formation of dynamic libraries of [n×n] imine components. The organocatalysis methodology has also been extended, under somewhat modified conditions, to reversible C?￡C/C?￡N exchange processes between Knoevenagel derivatives of barbituric acid and imines, allowing for the generation of increased diversity. Copyright
A transition metal free expedient approach for the C[dbnd]C bond cleavage of arylidene Meldrum's acid and malononitrile derivatives
Suresh, Muthiah,Kumari, Anusueya,Singh, Raj Bahadur
, (2019)
A transition metal free expedient approach for the C[dbnd]C bond cleavage of electron deficient alkenes such as arylidene Meldrum's acid and malononitrile derivatives are discussed. The C[dbnd]C bond of these compound were cleaved to benzoic acid in good yield at high temperature. Most importantly, with oxone in CH3CN/H2O at 45 °C or m-CPBA in DCM or NaClO2 in THF/H2O or PIDA in THF at room temperature furnished benzaldehyde derivatives selectively in excellent yields.
Monolithic and flexible polyimide film microreactors for organic microchemical applications fabricated by laser ablation
Min, Kyoung-Ik,Lee, Tae-Ho,Park, Chan Pil,Wu, Zhi-Yong,Girault, Hubert H.,Ryu, Ilhyong,Fukuyama, Takahide,Mukai, Yu,Kim, Dong-Pyo
, p. 7063 - 7067 (2010)
Keeping limber: A monolithic and flexible polyimide film microreactor is introduced for organic reactions and syntheses. Unlike glass microreactors, it is easy to fabricate, yet it is inert to solvents and acids under harsh conditions, unlike other polymer microreactors.
Controlled Aerobic Oxidation of Primary Benzylic Alcohols to Aldehydes Catalyzed by Polymer-Supported Triazine-Based Dendrimer-Copper Composites
Pan, Shiguang,Yan, Shuo,Osako, Takao,Uozumi, Yasuhiro
, p. 1152 - 1156 (2018)
A controlled aerobic oxidation of primary benzylic alcohols to the corresponding benzaldehydes by using polystyrene-poly(ethylene glycol) (PS-PEG) resin-supported triazine-based polyethyleneamine dendrimer-copper complexes [PS-PEG-TD2-Cu(II)] was developed. In particular, PS-PEG-TD2-Cu(OAc) 2 efficiently catalyzed the aerobic oxidation of benzylic alcohols in the presence of a catalytic amount of TEMPO under atmospheric conditions to give the corresponding aldehydes in up to quantitative yield. The catalyst was readily recovered by simple filtration and reused four times without significant loss of its catalytic activity.
A new fluorous/organic amphiphilic ether solvent, F-626: Execution of fluorous and high temperature classical reactions with convenient biphase workup to separate product from high boiling solvent
Matsubara, Hiroshi,Yasuda, Shinji,Sugiyama, Hiroyuki,Ryu, Ilhyong,Fujii, Yasuyuki,Kita, Katsumi
, p. 4071 - 4076 (2002)
A new fluorous/organic amphiphilic ether solvent, 1H,1H,2H,2H-perfluorooctyl 1,3-dimethylbutyl ether (F-626), is introduced. The basic properties of F-626, especially the partition coefficients with organic solvents/FC-72 (perfluorohexane), were investigated. F-626 was easy to remove by fluorous biphase treatment. Using F-626 as a solvent, LAH reduction, catalytic hydrogenation, and fluorous reductive radical reactions were successful. Classical high temperature reactions up to 200°C, such as the Vilsmeier formylation, the Wolff-Kishner reduction, and the Diels-Alder reaction, were also examined in F-626. The yields of the products in F-626 were almost comparable with those conducted in common organic solvents, which prove that F-626 has the potential to be an easily recyclable high boiling solvent.
Hypophosphorous acid-iodine: A novel reducing system. Part 2: Reduction of benzhydrols to diarylmethylene derivatives
Gordon, Paul E.,Fry, Albert J.
, p. 831 - 833 (2001)
A mixture of hypophosphorous acid (H3PO2) and iodine in acetic acid reduces a variety of substituted benzhydrols to the corresponding methylene derivatives in very high yields. The active reducing agent is hydrogen iodide generated by reaction between iodine and hypophosphorous acid.
Environmentally friendly organic synthesis using bismuth compounds: bismuth(III) iodide catalyzed deprotection of acetals in water
Bailey, Aaron D.,Baru, Ashvin R.,Tasche, Kendall K.,Mohan, Ram S.
, p. 691 - 694 (2008)
The chemoselective deprotection of a wide range of acetals and ketals in water is catalyzed by bismuth(III) iodide. Bismuth(III) compounds are remarkably nontoxic and hence are attractive as environmentally friendly catalysts.
Oxidative deprotection of oximes using pyridinium fluorochromate and hydrogen peroxide
Ganguly,Sukai,De,De
, p. 1607 - 1612 (2001)
A simple convenient procedure of oxidative deoximation has been developed using pyridinium fluorochromate (PFC), in combination with 30% hydrogen peroxide. The method has been found to be effective for a wide range of aliphatic and aromatic oximes, and may be used for selective cleavage of aldoximes in the presence of ketoximes.
Supramolecular Catalysis of the oxa-Pictet–Spengler Reaction with an Endohedrally Functionalized Self-Assembled Cage Complex
Harman, W. Hill,Hooley, Richard J.,Ngai, Courtney,Sanchez-Marsetti, Colomba M.
, p. 23505 - 23509 (2020)
An endohedrally functionalized self-assembled Fe4L6 cage complex can catalyze oxa-Pictet—Spengler cyclizations of tryptophols and various aldehyde derivatives, showing strong rate accelerations and size-selectivity. Selective molecular recognition of substrates controls the reactivity, and the cage is capable of binding and activating multiple different species along the multistep reaction pathway. The combination of a functionalized active site, size-selective reactivity, and multistep activation, all from a single host molecule, illustrates the biomimetic nature of the catalysis.
Discovery of indanone derivatives as multi-target-directed ligands against Alzheimer's disease
Huang, Ling,Miao, Hui,Sun, Yang,Meng, Fanchao,Li, Xingshu
, p. 429 - 439 (2014)
A series of indanone derivatives were designed, synthesized, and tested using a variety of assays to assess their potential as anti-Alzheimer's disease (AD) agents. The investigations assessed the activities of the agents for the inhibition of cholinesterases (AChE and BuChE), the inhibition of amyloid beta (Aβ) self-assembly, and the catalysis of the disassembly of preformed Aβ oligomers and measured their antioxidant activities. Our results demonstrate that most of the synthesized compounds demonstrated good inhibitory activity against AChE with IC50 values in the nanomolar range. In particular, compounds 9 (IC50 Combining double low line 14.8 nM) and 14 (IC50 Combining double low line 18.6 nM) exhibited markedly higher inhibitory activities than tacrine and similar activities to donepezil. In addition, 9 and 14 significantly inhibited Aβ aggregation (inhibition rates of 85.5% and 83.8%, respectively), catalysed the disaggregation of Aβ fibrils generated by self-induced Aβ aggregation, and exhibited antioxidant activity. Furthermore, these two compounds can cross the blood-brain barrier (BBB) in vitro. These properties highlight the potential of these new compounds to be developed as multi-functional drugs for the treatment of Alzheimer's disease.
A highly efficient heterogeneous aerobic alcohol oxidation catalyzed by immobilization of bipyridine copper(I) complex in MCM-41
Zhao, Hong,Chen, Qiurong,Wei, Li,Jiang, Yuanyuan,Cai, Mingzhong
, p. 8725 - 8731 (2015)
A heterogeneous copper(I)-catalyzed aerobic oxidation of primary benzylic and allylic alcohols to aldehydes was achieved under air in EtOH at 50°C in the presence of 5 mol % of MCM-41-immobilized bipyridine copper(I) complex [MCM-41-bpy-CuI] and 5 mol % of 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) using aqueous ammonia as base, yielding a variety of aromatic and α,β-unsaturated aldehydes in good to excellent yields. This heterogeneous copper catalyst can be easily recovered by a simple filtration of reaction solution and reused for at least 10 consecutive trials without any decreases in activity. The use of recyclable heterogeneous copper catalyst and green reagents, such as air as oxidant and ethanol as solvent, made the system attractive for environmentally sustainable processes.
A DFT and experimental study of the spectroscopic and hydrolytic degradation behaviour of some benzylideneanilines
Nelson, Peter N.,Robertson, Tahjna I.
, (2021/10/12)
The spectroscopic and hydrolytic degradation behaviour of some N-benzylideneanilines are investigated experimentally and theoretically via high quality density function theoretical (DFT) modelling techniques. Their absorption and vibrational spectra, accurately predicted by DFT calculations, are highly dependent on the nature of the substituents on the aromatic rings, hence, though some of their spectroscopic features are similar, energetic differences exist due to differences in their electronic structures. Whereas the o-hydroxy aniline derived adducts undergo hydrolysis via two pathways, the most energetically economical of which is initiated by a fast enthalpy driven hydration, over a conservative free energy (ΔG?) barrier of 53 kJ mol?1, prior to the rate limiting entropy controlled lysis step which occurs via a conservative barrier of ca.132 kJ mol?1, all other compounds hydrolyse via a slower two-step pathway, limited by the hydration step. Barriers heights for both pathways are controlled primarily by the structure and hence, stability of the transition states, all of which are cyclic for both pathways.
Catalytic study of the copper-based magnetic nanocatalyst on the aerobic oxidation of alcohols in water
Dehkordi, S. Saeid Saei,Albadi, Jalal,Jafari, Abbas Ali,Samimi, Heshmat Allah
, p. 2527 - 2538 (2021/03/24)
A copper-based magnetic nanocatalyst has been prepared by co-precipitation method and characterized by FESEM, EDS, TEM, XRD, XRF, ICP–OES, FTIR, and BET analysis. This new nanocatalyst displays a good activity toward the aerobic oxidation of a wide range of alcohols in water. Moreover, it is recyclable up to five following runs by simple filtration without any significant loss of its catalytic activity.
Zwitterion-induced organic-metal hybrid catalysis in aerobic oxidation
Hu, Rong-Bin,Lam, Ying-Pong,Ng, Wing-Hin,Wong, Chun-Yuen,Yeung, Ying-Yeung
, p. 3498 - 3506 (2021/04/07)
In many metal catalyses, the traditional strategy of removing chloride ions is to add silver salts via anion exchange to obtain highly active catalysts. Herein, we reported an alternative strategy of removing chloride anions from ruthenium trichloride using an organic [P+-N-] zwitterionic compound via multiple hydrogen bond interactions. The resultant organic-metal hybrid catalytic system has successfully been applied to the aerobic oxidation of alcohols, tetrahydroquinolines, and indolines under mild conditions. The performance of zwitterion is far superior to that of many other common Lewis bases or Br?nsted bases. Mechanistic studies revealed that the zwitterion triggers the dissociation of chloride from ruthenium trichloride via nonclassical hydrogen bond interaction. Preliminary studies show that the zwitterion is applicable to catalytic transfer semi-hydrogenation.
