- Synthesis, characterization, crystal structures, Hirshfeld surface analysis, DFT computational studies and catalytic activity of novel oxovanadium and dioxomolybdenum complexes with ONO tridentate Schiff base ligand
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For the first time, two new oxovanadium and dioxomolybdenum Schiff base complexes, VOL(OMe) and MoO2L, were synthesized through the reaction of a ONO tridentate Schiff base ligand (H2L) derived from the condensation of 5-bromosalicyl
- Kargar, Hadi,Bazrafshan, Maryam,Fallah-Mehrjardi, Mehdi,Behjatmanesh-Ardakani, Reza,Rudbari, Hadi Amiri,Munawar, Khurram Shahzad,Ashfaq, Muhammad,Tahir, Muhammad Nawaz
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- Silica functionalized Cu(II) catalysed selective oxidation of benzyl alcohols using TEMPO and molecular oxygen as an oxidant
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A general scheme for the oxidation of benzyl alcohols catalyzed by silica functionalized copper (II) has been designed. TEMPO, a free radical, assists this oxidation that was initiated by molecular oxygen which converts it to a primary oxidant. This catalytic combination i.e. SiO2-Cu(II) in presence of TEMPO and oxygen provides excellent results in terms of yields and reaction time. SiO2-Cu(II) was very well characterized by different spectroscopic techniques such as FTIR, XRD, TGA, XPS, EDAX, SEM, TEM and AAS and is recyclable upto five times which makes it economically beneficial. [Figure not available: see fulltext.]
- Sharma, Pankaj,Gupta, Monika,Gupta, Rajive,Gupta, Manjulla
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- Oxidation of Benzylic and Allylic Alcohols with Cobalt(III) Acetate in Acetic Acid in the Presence and Absence of Sodium Bromide
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Benzyl alcohol and its o-, m-, and p-substituted derivatives afforded fairly good yields of the corresponding benzaldehydes through a reaction with a Co(III)-NaBr system.With allylic alcohols, this system failed in a selective formation of unsaturated carbonyl compounds.In the latter cases, the products were effectively obtained by using a higher concentration of cobalt(III)acetate in the absence of NaBr.
- Hirano, Masao,Morimoto, Takashi,Itoh, Keiko
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- Acid catalyzed synthesis of 2-(2-aminophenyl)quinazoline-4-amine and reaction with aromatic aldehydes
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The hydrochloride salt of 2-(2-aminophenyl)quinazoline-4-amine, prepared from a quinazolino[3,4-a]quinazoline, was reacted with aromatic aldehydes under conventional heating or microwave irradiation, leading to high yields of tetracyclic dihydroquinazolines.
- Marinho, Elina,Proen?a, M. Fernanda
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- Synthesis, spectral characterization, SC-XRD, HSA, DFT and catalytic activity of a dioxidomolybdenum complex with aminosalicyl-hydrazone Schiff base ligand: An experimental and theoretical approach
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A new dioxidomolybdenum(VI) complex has been successfully prepared by the reaction of an ONO donor Schiff base, derived by condensing 4-amino-2-hydroxybenzohydrazide and 3-methoxysalicylaldehyde, with MoO2(acac)2. The structures of s
- Kargar, Hadi,Fallah-Mehrjardi, Mehdi,Behjatmanesh-Ardakani, Reza,Munawar, Khurram Shahzad,Ashfaq, Muhammad,Tahir, Muhammad Nawaz
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- Oxidation of benzyl alcohols to benzaldehydes in water catalyzed by a Cu(II) complex with a zwitterionic calix[4]arene ligand
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Abstract A water-soluble cationic mononuclear copper(II) complex [Cu(II)L(H2O)]I2 (1, H4L = 5,11,17,23-tetrakis(trimethylammonium)-25,26,27,28-tetrahydroxycalix[4]arene) was employed as a catalyst in the oxidation of benzyl alcohols to benzaldehydes in water. In the presence of TEMPO and H2O2, complex 1 exhibited good catalytic activity towards primary benzyl alcohols with a less catalyst loading (0.25 mol%) and a lower temperature (60 °C). The isolated yields of the aldehydes achieved 63-98% within 12 h.
- Gao, Jun,Ren, Zhi-Gang,Lang, Jian-Ping
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- Synthesis, Structure, Biological Evaluation, and Catalysis of Two Pyrazole-Functionalized NHC–RuIIComplexes
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Two ruthenium complexes, 3a and 3b, bearing pyrazole-functionalized N-heterocyclic carbenes (NHCs) were prepared, and their structures were characterized by X-ray diffraction analysis. Given their promising anticancer potential, we evaluated the cytotoxic
- Chen, Chao,Ni, Shengliang,Zheng, Qing,Yu, Meifang,Wang, Hangxiang
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- Novel oxovanadium and dioxomolybdenum complexes of tridentate ONO-donor Schiff base ligand: Synthesis, characterization, crystal structures, Hirshfeld surface analysis, DFT computational studies and catalytic activity for the selective oxidation of benzyl
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Two new oxovanadium and dioxomolybdenum Schiff base complexes, [VvO(L)(OCH3)(CH3OH)] and [MoVIO2(L)(CH2CH3OH)], were synthesized by treating an ONO-donor type Schiff base ligand
- Amiri Rudbari, Hadi,Ashfaq, Muhammad,Behjatmanesh-Ardakani, Reza,Fallah-Mehrjardi, Mehdi,Forootan, Pooran,Kargar, Hadi,Nawaz Tahir, Muhammad,Shahzad Munawar, Khurram
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- A frank synthesis of alkyl-aryl ethers from 2-halobenzaldehydes and aromatic olefins without transition metal co-catalyst and ligand
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An efficient synthesis of alkyl ethers has been developed for o-deactivated aryl halides and 1-halotetralenes. The method shows good regioselectivity towards ortho substituted halides. Alkali metal carbonates (Li2CO3/Na2CO3/K2CO3/Cs2CO3) have been used without a transition metal co-catalyst and ligand. The method is simple, straight-forward and proceeds to afford products in good isolated yields. The method holds potential for future applications in organic synthesis.
- Kumar, Balagani Sathish,Negi, Arvind S.
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- Synthesis, characterization and application of γ-MnO2/graphene oxide for the selective aerobic oxidation of benzyl alcohols to corresponding carbonyl compounds
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A facile low temperature approach was used to synthesize γ-MnO2 on the surface of graphene oxide (GO) through a simple wet precipitation method using MnSO4 as a precursor. X-ray diffraction analysis and Raman spectroscopy confirmed the formation of γ-phase MnO2 in the MnO2/GO nanocomposites. Transmission electron microscopy studies showed that γ-MnO2 exists as flower and needle structures in GO with an average size of approximately 15 nm. Inductively coupled plasma atomic emission spectroscopy studies confirmed a 62.5 wt% loading of γ-MnO2 in the GO nanocomposites. The γ-MnO2/GO catalyst shows good activity for the selective aerobic oxidation of benzyl alcohols to corresponding carbonyl compounds even when present in sub-stoichiometric amounts giving 91% yield over 3 h under mild reaction conditions. The catalyst showed high activity even after three cycles indicating good recyclability.
- Kadam, Mahesh M.,Dhopte, Kiran B.,Jha, Neetu,Gaikar, Vilas G.,Nemade, Parag R.
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- Selective oxidation of benzyl alcohols to benzaldehydes catalyzed by dioxomolybdenum Schiff base complex: synthesis, spectral characterization, crystal structure, theoretical and computational studies
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A novel dioxomolybdenum Schiff base complex, MoO2L·DMF, was synthesized by treating MoO2(acac)2 with an ONO donor Schiff base ligand (H2L) derived by the condensation of 4-aminobenzohydrazide and 3-methoxysalicy
- Kargar, Hadi,Fallah-Mehrjardi, Mehdi,Behjatmanesh-Ardakani, Reza,Munawar, Khurram Shahzad,Ashfaq, Muhammad,Tahir, Muhammad Nawaz
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- α-MnO2 modified exfoliated porous g-C3N4 nanosheet (2D) for enhanced photocatalytic oxidation efficiency of aromatic alcohols
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Porous graphitic carbon nitride (g-C3N4) was synthesized by taking melamine and ammonium bicarbonate through single-step calcination method followed by ultrasonication to obtain exfoliated porous g-C3N4 (2D) nanosheets. Further enhancement of photocatalytic performance, g-C3N4 nanosheet (2D) was further modified with different weight percentage of (1, 3, 5, and 7) of MnO2. The introduction of α-MnO2 onto the g-C3N4 nanosheet establishes an interlayer channels to promote the migration of charge carriers through the valence band and conduction band of the prepared composite MnO2@g-C3N4. The transformation of photo induced charge carriers adopt the Z-scheme mechanism rather band-transfer mechanism. The accumulated photo generated electrons in conduction band of g-C3N4 is more electro negative than the potential of (O2/O2–.) and able to reduce oxygen to superoxide (O2–.) radical. At the same time, the holes in valence band of α-MnO2 are more electro positive than the potential of (OH–/OH.) and help in oxidate OH– to hydroxyl (OH.) radical. Among all the composites, 3 wt% MnO2 modified g-C3N4 shows the best photocatalytic oxidation efficiency towards all the aromatic alcohols. In presence of visible light, heterojuction formation, and formation of active charged species (OH. and O2–.) were mostly responsible for photocatalytic oxidation of aromatic alcohols through free radical mechanism.
- Nanda, Binita,Nanda, Braja B.,Pradhan, Manas Ranjan,Rath, Dharitri,Sethi, Ratikanta
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- Synthesis of new Zn (II) complexes for photo decomposition of organic dye pollutants, industrial wastewater and photo-oxidation of methyl arenes under visible-light
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Synthesis of new Schiff's base Zn-complexes for photo-oxidation of methyl arenes and xylenes are reported under visible light irradiation conditions. All the synthesized new ligands and Zn-complexes are thoroughly characterized with various spectral analyses and confirmed as 1:1 ratio of Zn and ligand with distorted octahedral structure. The bandgap energies of the ligands are higher than its Zn-complexes. These synthesized new Zn(II) complexes are used for the photo-fragmentation of organic dye pollutants, photodegradation of food industrial wastewater and oxidation of methyl arenes which are converted into its respective aldehydes with moderate yields under visible light irradiation. The photooxidation reaction dependency on the intensity of the visible light was also studied. With the increase in the dosage of photocatalyst, the methyl groups are oxidized to get aldehydes and mono acid products, which are also identified from LC-MS data. Finally, [Zn(PPMHT)Cl] is with better efficiency than [Zn(PTHMT)Cl] and [Zn(MIMHPT)Cl] for oxidation of methyl arenes is reported under visible-light-driven conditions.
- Ahemed, Jakeer,Bhongiri, Yadagiri,Chetti, Prabhakar,Gade, Ramesh,Kore, Ranjith,Pasha, Jakeer,Pola, Someshwar,Rao D, Venkateshwar
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- Selective Electrochemical Oxygenation of Alkylarenes to Carbonyls
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An efficient electrochemical method for benzylic C(sp3)-H bond oxidation has been developed. A variety of methylarenes, methylheteroarenes, and benzylic (hetero)methylenes could be converted into the desired aryl aldehydes and aryl ketones in moderate to excellent yields in an undivided cell, using O2 as the oxygen source and lutidinium perchlorate as an electrolyte. On the basis of cyclic voltammetry studies, 18O labeling experiments, and radical trapping experiments, a possible single-electron transfer mechanism has been proposed for the electrooxidation reaction.
- Li, Xue,Bai, Fang,Liu, Chaogan,Ma, Xiaowei,Gu, Chengzhi,Dai, Bin
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supporting information
p. 7445 - 7449
(2021/10/02)
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- SBA-15 Supported Silver Catalyst for the Efficient Aerobic Oxidation of Toluene Under Solvent-Free Conditions
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The efficient SBA-15 supported silver catalysts(Ag/SBA-15) were prepared and characterized by ICP-OES, XRD, TEM, SEM, XPS and N2 adsorption–desorption techniques. The catalysts exhibited an excellent catalytic activity for the aerobic oxidation of toluene to benzaldehyde under solvent-free conditions. Conversion of toluene and selectivity of benzaldehyde were 50% and 89% respectively over catalyst with 9.1 wt% Ag loading (10Ag/SBA-15). A wide range of substrates were tolerated under the selected reaction conditions. The kinetic study shows that the oxidation of toluene over 10Ag/SBA-15 is pseudo-first-order reaction and the activation energy Ea is 45.1?kJ/mol. A plausible mechanism involving oxygen free radicals was proposed for the aerobic oxidation reaction. Compared with the traditional method, the newly designed heterogeneous catalytic system shows better economic applicability, environmental friendliness and broader application prospects. Graphical abstract: [Figure not available: see fulltext.]
- Chen, Lei,Chen, Yanjiao,Dai, Xuan,Guo, Jiaming,Peng, Xinhua
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- C70Fullerene Catalyzed Photoinduced Aerobic Oxidation of Benzylamines to Imines and Aldehydes
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C70 fullerene catalyzed photoinduced oxidation of benzylic amines at ambient conditions has been explored here. The developed strategy's main feature includes the additive/oxidant-free conversion of benzylic amine to corresponding imine and aldehydes. The reaction manifests broad substrate scope with excellent function group leniency and is applicable up to the gram scale. Further, symmetrical secondary amines can also be synthesized from benzylic amine in a one-pot two-step process. Various experiments and density functional theory studies revealed that the current reaction involves the generation of reactive oxygen species, single electron transfer reaction, and benzyl radical formation as key steps under photocatalytic conditions.
- Kumar, Inder,Kumar, Rakesh,Gupta, Shiv Shankar,Sharma, Upendra
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supporting information
p. 6449 - 6457
(2021/05/29)
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- Method for synthesizing 2 -methoxycinnamaldehyde
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The invention provides a synthetic method of 2 -methoxycinnamaldehyde, and belongs to the technical field of organic synthesis. The synthesis method provided by the invention comprises the following steps: (1) methylation reaction of 2 - hydroxybenzaldehyde and a methylation reagent under the action of a quaternary ammonium salt catalyst to obtain 2 - methoxybenzaldehyde. (2) Under alkaline conditions, 2 - methoxybenzaldehyde is subjected to a condensation reaction with acetaldehyde to obtain 2 -methoxycinnamaldehyde. 2 - Hydroxybenzaldehyde is used as a starting material, and the method has the advantages of wide sources and low cost. The method has the advantages of short synthetic route and less side reaction, and the obtained 2 -methoxycinnamaldehyde has high yield and purity and is suitable for industrial popularization and application. The results show that the yield 2 - and the purity ≥ 90% of ≥ 95% -methoxycinnamaldehyde obtained by the synthesis method provided by the invention are high.
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Paragraph 0076-0079; 0083-0086
(2021/11/19)
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- Homogeneous CuCl2/TMEDA/TEMPO-Catalyzed chemoselective base- and halogen- free aerobic oxidation of primary alcohols in mild conditions
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This article describes the developing of a base- and halogen- free homogeneous system aiming to chemoselectively oxidize allyl, furyl, aryl and heteroaryl primary alcohols. The current easy-to-handle aerobic system uses few amounts of CuCl2/TMEDA/TEMPO system under mild reaction conditions to produce aldehydes in high yields. Moreover, the CuCl2/TMEDA cyclic voltammetry was measured for the first time, disclosing that TMEDA as ligand substantially affects the redox potential (E1/2) of the couple E1/2Cu2+/Cu+ to E1/2Cu2+/Cu+-TMEDA by 454 mV in the redox system.
- Alves, Otávio A. L.,Chagas, Rafael C. R.,Princival, Jefferson L.,Ribeiro, RogérioT.,Silva, Emmanuel D.,Villar, José A. F. P.
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- Fe(III) superoxide radicals in halloysite nanotubes for visible-light-assisted benzyl alcohol oxidation and oxidative C[sbnd]C coupling of 2-naphthol
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Selective oxidation of benzyl alcohols to aldehydes and 2-naphthol to BINOL was achieved by activation of molecular oxygen (O2) and hydrogen peroxide (H2O2) over an iron-oxide catalyst embedded in halloysite nanotube. Electron spin resonance spectroscopy (ESR), Raman and in situ FTIR spectroscopic analysis provided direct evidence for the involvement of superoxide radical bound FeIII species in the oxidation reaction. Both the analysis suggested the end-on binding of superoxide radical with FeIII-centre. The stability of such radical bound FeIII-species in halloysite nanotube was analyzed through density functional theory (DFT) calculations. Results suggested that end-on (η1) binding was favourable by 13.5 kcal/ mol than the side-on (η2) binding mode. The formation of such reactive species was believed to play the crucial role in bringing the high selectivity in the catalytic oxidation of benzyl alcohol and oxidative C[sbnd]C coupling of 2-naphthol. UV–Vis spectroscopic studies on the oxidation of benzyl alcohol suggested for the initial adsorption of substrate molecule on the catalyst surface followed by its interaction with FeIII -superoxide/hydroperoxide species generated upon photoirradiation with visible light in presence of O2. The presence of a suitable band gap ~2.14 eV enabled the catalyst to catalyze the reaction under visible light irradiation. Both the reactions (benzyl alcohol and 2-naphthol oxidation) were tested in presence of both O2 and H2O2 as oxidants at ambient temperature. The influence of different parameters like rate of oxygen flow, amount of peroxide, nature of solvent, and catalyst amount on the conversion and selectivity of the reactions were studied to understand their role in the catalytic reactions. Successful oxidation of 2-naphthol with H2O2 as oxidant was a real success to overcome the limitations associated with this reaction using H2O2 as oxidant.
- Bania, Kusum K.,Baruah, Manash J.,Bora, Tonmoy J.,Dutta, Rupjyoti,Guha, Ankur Kanti,Roy, Subhasish
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- Synthesis, characterization, reactivity, and catalytic studies of heterobimetallic vanadium(V) complexes containing hydrazone ligands
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Six heterobimetallic alkali metal dioxidovanadium(V) coordination polymer complexes {[M6{VO(μ-O)}2(μ-OH)4(μ4-slox/nph)].n DMF}∞ where M = Na, K, and Cs; n = 1 for (1), 0 for (2)-(6) of two dihydrazone ligands, disalicylaldehydeoxaloyldihydrazone (H4slox) and bis(2-hydroxy-1-naphthaldehyde)oxaloyldihydrazone (H4nph) are reported. All the complexes have been characterized by various physicochemical techniques such as elemental analyses, molar conductance, IR, NMR, UV–vis, and cyclic voltammetry. The IR, 1HNMR, and 13CNMR spectral data suggest that the dihydrazones are coordinated through phenolate/naphtholate oxygen, enolate oxygen, and azine nitrogen atoms to the metal centres. The structure of complex {[Na6{VO(μ-O)}2(μ-OH)4(μ4-slox)].DMF}∞ (1) is also determined by single-crystal X-ray data, which revealed that the H4slox coordinated via all possible dative sites to metal centres as tetrabasic octadentate ligand. The vanadium metal centres adopted distorted square-pyramidal coordination geometries, and the sodium atoms are also in five coordination atmospheres. The electronic spectra of the complexes showed LMCT bands in addition to intra-ligand π → π* and n → π* transitions. As evident from the cyclic voltammetry, the complexes showed two metal-centred electron transfer reactions {[(VVVV(slox)2?/VVVIV(slox)3?] and [(VVVIV(slox)3?/VVVIV(slox)4?]}, in addition to the ligand centred electron transfer reactions. Further, bovine serum albumin (BSA interaction studies of the complexes {[Na6{VO(μ-O)}2(μ-OH)4(μ4-slox)].DMF}∞ (1) and [Na6{VO(μ-O)}2(μ-OH)4(μ4-nph)]∞ (4) revealed strong binding affinity. Moreover, the catalytic studies of the complexes (1) and (4) were found to be effective for the oxidation of alcohols into their corresponding aldehydes and ketones and bromination of some organic substrates in the presence of H2O2 as an oxidizing agent.
- Borthakur, Rosmita,Dhanpat, Shobha A.,Kumar, Arvind,Kurbah, Sunshine D.,Lal, Ram A.,Syiemlieh, Ibanphylla
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- Efficient synthesis of acrylates bearing an aryl or heteroaryl moiety: One-pot method from aromatics and heteroaromatics using formylation and the horner-wadsworth-emmons reaction
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Acrylates bearing an aryl or heteroaryl moiety were efficiently prepared by a one-pot process employing a sequence of lithiation, formylation and the Horner-Wadsworth-Emmons reaction starting from aromatic and heteroaromatic compounds. This method can efficiently introduce an acrylate moiety into aromatic and heteroaromatic compounds.
- Yasukata, Tatsuro,Matsuura, Takaharu
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p. 527 - 533
(2021/03/22)
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- Acceptorless Dehydrogenative Cross-Coupling of Primary Alcohols Catalyzed by an N-Heterocyclic Carbene-Nitrogen-Phosphine Chelated Ruthenium(II) Complex
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The acceptorless dehydrogenative cross-coupling of primary alcohols to form cross-esters with the liberation of H2 gas was enabled using a [RuCl(η6-C6H6)(κ2-CNP)][PF6]Cl complex as the catalyst. This sustainable protocol is applicable to a broad range of primary alcohols, particularly for the sterically demanding ones, featuring good functional group tolerance and high selectivity. The good catalytic performance can be attributed to the nitrogen-phosphine-functionalized N-heterocyclic carbene (CNP) ligand, which adopts a facial coordination mode as well as the facile dissociation of coordinated benzene.
- Chen, Hua,Cui, Tianhua,Fu, Haiyan,He, Xiaochun,Jiang, Weidong,Li, Ruixiang,Nie, Xufeng,Xu, Jiaqi,Yuan, Maolin,Zhao, Ling,Zheng, Xueli
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- CO2-Mediated Non-Destructive Cyanide Wastewater Treatment
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The facile removal of cyanide anions from cyanide-containing water was achieved using CO2 in conjunction with aldehydes which can be recycled from the process. The conversion of the cyanide ion into an insoluble cyanohydrin in water allowed the removal of cyanide and could be used as a method for treating cyanide contaminated wastewater and for recovering cyanide or cyanohydrins for further applications.
- Juhl, Martin,Lee, Ji-Woong,Petersen, Allan R.,Petrovic, Aleksa
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p. 5003 - 5007
(2021/09/30)
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- Photoredox-Catalyzed Simultaneous Olefin Hydrogenation and Alcohol Oxidation over Crystalline Porous Polymeric Carbon Nitride
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Booming of photocatalytic water splitting technology (PWST) opens a new avenue for the sustainable synthesis of high-value-added hydrogenated and oxidized fine chemicals, in which the design of efficient semiconductors for the in-situ and synergistic utilization of photogenerated redox centers are key roles. Herein, a porous polymeric carbon nitride (PPCN) with a crystalline backbone was constructed for visible light-induced photocatalytic hydrogen generation by photoexcited electrons, followed by in-situ utilization for olefin hydrogenation. Simultaneously, various alcohols were selectively transformed to valuable aldehydes or ketones by photoexcited holes. The porosity of PPCN provided it with a large surface area and a short transfer path for photogenerated carriers from the bulk to the surface, and the crystalline structure facilitated photogenerated charge transfer and separation, thus enhancing the overall photocatalytic performance. High reactivity and selectivity, good functionality tolerance, and broad reaction scope were achieved by this concerted photocatalysis system. The results contribute to the development of highly efficient semiconductor photocatalysts and synergistic redox reaction systems based on PWST for high-value-added fine chemical production.
- Qiu, Chuntian,Sun, Yangyang,Xu, Yangsen,Zhang, Bing,Zhang, Xu,Yu, Lei,Su, Chenliang
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p. 3344 - 3350
(2021/07/26)
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- A Magnetically Recyclable Palladium-Catalyzed Formylation of Aryl Iodides with Formic Acid as CO Source: A Practical Access to Aromatic Aldehydes
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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.
- You, Shengyong,Zhang, Rongli,Cai, Mingzhong
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p. 1962 - 1970
(2021/01/25)
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- Nickel catalyzed hydrosilane reduction of (het)arenecarboxylic acids into aldehydes
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Nickel-catalyzed reduction of (het)arenecarboxylic acids with hydrosilanes in the presence of dimethyl dicarbonate as the activator affords the corresponding aldehydes. The role of the activator is the conversion of the acids into their anhydrides undergoing C–O cleavage. The good yields were achieved in case of substrates bearing electron-donating and electron-neutral groups.
- Wang, Liang,Wang, Yaoyao,Tao, Yu,Zhang, Nana,Li, Shubai
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p. 271 - 273
(2021/05/04)
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- Method for preparing aldehyde compounds by oxidative cleavage of carbon-carbon bonds of terminal alkene compounds
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The invention discloses a method for preparing aldehyde compounds by oxidizing and breaking carbon-carbon bonds of terminal alkene compounds. The method comprises the following steps: adding an alkene-terminated compound, an additive and a nitrogen-doped mesoporous carbon-loaded monatomic catalyst into a fatty primary alcohol solvent, putting into a pressure container, sealing, introducing oxygen source gas with a certain pressure, controlling the pressure of the oxygen source gas to be 0.1-1MPa and the reaction temperature to be 80-150 DEG C, and obtaining a reaction product, namely the aldehyde compound. The nitrogen-doped mesoporous carbon-loaded monatomic catalyst adopted by the invention is high in activity, the highest separation yield of the aldehyde compound as a reaction product reaches 99%, the method is wide in application range, the reaction conditions are easy to control, the catalyst can be recycled, the post-treatment is simple, and the method is suitable for industrial production.
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Paragraph 0043-0044; 0089-0090
(2021/06/06)
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- Aqueous extract of Shikakai; a green solvent for deoximation reaction: Mechanistic approach from experimental to theoretical
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This article describes a green method for regeneration of carbonyl compounds from various types of oxime compounds under microwave radiation using I2 and aqueous saponin solution isolated from Shikakai. Effect of saponin concentration on yield percentage of regenerated different types of carbonyl compounds has been discussed. A correlation has been established between saponin concentration and yield percentage of carbonyl compounds. Mechanism of interaction between oxime and saponin is established on the basis of density functional theory. In addition, the quantum chemical parameters for saponin have been determined. Furthermore, electrostatic surface analysis of the saponin is carried out to confirm the mechanism of interaction between saponin and oximes.
- Das, Debadutta,Kudrat-E-Zahan, Md.,Mahal, Ahmed,Mohapatra, Ranjan K.,Parhi, Pankaj K.,Sahu, Raghaba,Sarangi, Ashish K.
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- Rhodium-catalyzed reductive carbonylation of aryl iodides to arylaldehydes with syngas
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The reductive carbonylation of aryl iodides to aryl aldehydes possesses broad application prospects. We present an efficient and facile Rh-based catalytic system composed of the commercially available Rh salt RhCl3·3H2O, PPh3 as phosphine ligand, and Et3N as the base, for the synthesis of arylaldehydes via the reductive carbonylation of aryl iodides with CO and H2 under relatively mild conditions with a broad substrate range affording the products in good to excellent yields. Systematic investigations were carried out to study the experimental parameters. We explored the optimal ratio of Rh salt and PPh3 ligand, substrate scope, carbonyl source and hydrogen source, and the reaction mechanism. Particularly, a scaled-up experiment indicated that the catalytic method could find valuable applications in industrial productions. The low gas pressure, cheap ligand and low metal dosage could significantly improve the practicability in both chemical researches and industrial applications.
- Chen, Suqing,Liu, Zhenghui,Mu, Tiancheng,Wang, Peng,Yan, Zhenzhong,Yu, Dongkun,Zhao, Xinhui
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p. 645 - 656
(2020/05/14)
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- Magnetic nanoparticle supported ionic liquid phase catalyst for oxidation of alcohols
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Anew magnetic nanoparticle supported ionic liquid phase (SILP) catalyst containing perruthenate anions was prepared by a multistep procedure. The various analytical techniques such as FT-IR spectroscopy, X-ray photoelectron spectroscopy, transmission elec
- Naikwade, Altafhusen,Jagadale, Megha,Kale, Dolly,Rashinkar, Gajanan
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p. 1088 - 1097
(2020/10/20)
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- Amine-functionalized metal-organic framework-based Pd nanoparticles: Highly efficient multifunctional catalysts for base-free aerobic oxidation of different alcohols
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A palladium (Pd) nanoparticle containing a metal organic framework (MOF) is described as a highly efficient multifunctional catalyst for the aerobic oxidation of different aliphatic, aromatic and heteroaromatic alcohols in toluene. The catalytic efficienc
- Taher, Abu,Susan, Md. Abu Bin Hasan,Begum, Noorjahan,Lee, Ik-Mo
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p. 19113 - 19121
(2020/11/23)
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- AN EFFICIENT AND ENVIRONMENT FRIENDLY PROCESS FOR CHLOROMETHYLATION OF SUBSTITUTED BENZENES
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Disclosed herein is an efficient, environment friendly and commercially viable process for preparation of chloromethylated compound of formula I in substantially pure form and high yield, from the compound of formula II. The process includes contacting the compound of formula II with a chloromethylating agent generated in-situ by reaction of a formaldehyde precursor and hydrogen chloride, in a suitable solvent/contacting medium and in the presence of a catalytic amount of a short chain/low molecular weight carboxylic acid of formula III. I II III wherein, R1, R2, R3 and R4 are as defined in the description.
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Paragraph 0078
(2020/12/30)
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- Synthetic method of aryl aldehyde compound (by machine translation)
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The method is simple to operate, the reaction conditions are mild, raw materials and the catalyst are cheap and easily available . the reaction yield is higher, and the method is environment-friendly and green in synthesis method, is an environment-friendly synthesis method of the aromatic aldehyde compound, at room temperature, through an oxidation decarboxylation reaction, of the arylamine compounds. (by machine translation)
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Paragraph 0057-0062
(2020/04/17)
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- Visible-light-promoted oxidative decarboxylation of arylacetic acids in air: Metal-free synthesis of aldehydes and ketones at room temperature
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A metal-free photocatalytic oxidative decarboxylation reaction at room temperature was developed for the synthesis of aromatic aldehydes and ketones from the corresponding arylacetic acids. The reaction was realized under blue-light irradiation by adding 1 molpercent of 4CzIPN as photocatalyst and air as oxidant. This reaction represents a novel decarboxylation of a sp3-hybridized carboxylic acids without traditional heating, additional oxidants, and metal reagents under mild conditions.
- He, Shuaiqi,Chen, Xiaolan,Zeng, Fanlin,Lu, Peipei,Peng, Yuyu,Qu, Lingbo,Yu, Bing
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supporting information
p. 1863 - 1867
(2020/01/03)
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- Selective photoredox decarboxylation of α-ketoacids to allylic ketones and 1,4-dicarbonyl compounds dependent on cobaloxime catalysis
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A photoredox/cobaloxime co-catalyzed coupling reaction of α-ketoacids and methacrylates to obtain allylic ketones is described. Without the cobaloxime catalyst, 1,4-dicarbonyl compounds are generated. The cobaloxime catalyst enables dehydrogenation to generate the formation of new olefins. The generality, good substrate scope and mild conditions are good features in the photoredox/cobaloxime catalysis protocol, and this method will provide new opportunities for the functionalization of more olefins.
- Zhang, Hong,Xiao, Qian,Qi, Xu-Kuan,Gao, Xue-Wang,Tong, Qing-Xiao,Zhong, Jian-Ji
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supporting information
p. 12530 - 12533
(2020/11/02)
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- Cerium(IV) Carboxylate Photocatalyst for Catalytic Radical Formation from Carboxylic Acids: Decarboxylative Oxygenation of Aliphatic Carboxylic Acids and Lactonization of Aromatic Carboxylic Acids
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We found that in situ generated cerium(IV) carboxylate generated by mixing the precursor Ce(OtBu)4 with the corresponding carboxylic acids served as efficient photocatalysts for the direct formation of carboxyl radicals from carboxylic acids under blue light-emitting diodes (blue LEDs) irradiation and air, resulting in catalytic decarboxylative oxygenation of aliphatic carboxylic acids to give C-O bond-forming products such as aldehydes and ketones. Control experiments revealed that hexanuclear Ce(IV) carboxylate clusters initially formed in the reaction mixture and the ligand-to-metal charge transfer nature of the Ce(IV) carboxylate clusters was responsible for the high catalytic performance to transform the carboxylate ligands to the carboxyl radical. In addition, the Ce(IV) carboxylate cluster catalyzed direct lactonization of 2-isopropylbenzoic acid to produce the corresponding peroxy lactone and ?3-lactone via intramolecular 1,5-hydrogen atom transfer (1,5-HAT).
- Hirosawa, Keishi,Mashima, Kazushi,Satoh, Tetsuya,Shinohara, Koichi,Shirase, Satoru,Tamaki, Sota,Tsurugi, Hayato
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supporting information
(2020/03/25)
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- Aerobic alcohol oxidation catalyzed by CuO-rectorite/TEMPO in water
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An environmentally benign CuO-rectorite was prepared by calcining the co-precipitation product of Cu2+ with an acid-activated rectorite at pH 6. It could be well dispersed in water and used as a co-catalyst with TEMPO to selectively aerobically oxidize alcohols to aldehydes. The conversion of most primary benzylic alcohols was very high under optimized conditions. Interestingly, the oxidation protocol also allowed highly selective transformation of benzylic alcohols containing a phenolic hydroxyl group into the corresponding aldehydes. Additionally, very little copper was leached from the catalyst during the catalytic reaction. CuO-rectorite could be reused by centrifugation and washed with acetonitrile and water. At the same time, its catalytic activity remained high.
- Liu, Wanghui,Yang, Jianhong,Cai, Jun
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p. 549 - 561
(2018/10/15)
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- A molybdenum based metallomicellar catalyst for controlled and chemoselective oxidation of activated alcohols in aqueous medium
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A surfactant based oxodiperoxo molybdenum complex, which could activate molecular oxygen, has been employed as a catalyst for controlled oxidation of benzylic alcohols to corresponding carbonyls. The oxidation reactions were carried out under aqueous environment, however, in the absence of any extraneous base or co-catalyst. Sensitive/oxidizable functional groups like cyano, sulfide, hydroxyl, aryl-hydroxyl, alkene (internal/terminal), alkyne (internal/terminal), and acetal were tolerated during the transformations. Such selectivity is attributed to the mild nature of the catalyst. The methodology could also be scaled-up for multi-gram synthesis and the protocol is likely to find practical use since it requires an inexpensive recyclable-catalyst and easily available oxidant (under green conditions). A plausible mechanism is proposed with the help of preliminary computational study.
- Thiruvengetam, Prabaharan,Chakravarthy, Rajan Deepan,Chand, Dillip Kumar
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p. 123 - 133
(2019/07/19)
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- Synthesis, crystal structure and reactivity of homobimetallic vanadium(V) complexes derived from oxaloyldihydrazone ligands
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Treatment of V2O5 with dihydrazone ligands (H4L) (disalicylaldehydeoxaloyldihydrazone (H4L1 = H4slox), bis(2-hydroxy-1-naphthaldehyde)oxaloyldihydrazone (H4L2 = H4nph) and bis(5-bromosalicylaldehyde)oxaloyldihydrazone (H4L3 = H4sloxBr)) in methanol leads to the formation of homobimetallic vanadium(V) complexes of the composition [(CH3)2NH2]2[(VO2)2(L)]·nH2O, where n = 2 (1, 2) and n = 4 (3). The reaction of complexes 1–3 with H2O2 results in the formation of bis(monooxidoperoxidovanadate(V)) complexes[{VO(O2)}2(L)]2? and the reaction with HCl leads to the formation of oxidohydroxido species of the composition [(VO(OH)(L)]2?. The complexes show great potential for the oxidation of alcohols and the oxidative bromination of some organic substrates.
- Syiemlieh, Ibanphylla,Asthana, Mrityunjaya,Kurbah, Sunshine D.,Lal, Ram A.
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p. 202 - 216
(2019/06/19)
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- Stepwise degradation of hydroxyl compounds to aldehydes: Via successive C-C bond cleavage
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Stepwise degradation of hydroxyl compounds to aldehydes via successive cleavage of C-C bonds was achieved by using a bimetallic catalytic system (PdCl2 + CuCl) without any ligands and additives. The broad applicability is expanded to a diverse range of aromatic, aliphatic, primary and secondary alcohols, as well as lignin model compounds.
- Liu, Mingyang,Zhang, Zhanrong,Shen, Xiaojun,Liu, Huizhen,Zhang, Pei,Chen, Bingfeng,Han, Buxing
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supporting information
p. 925 - 928
(2019/01/24)
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- Iron-catalyzed oxidative C-C(vinyl) σ-bond cleavage of allylarenes to aryl aldehydes at room temperature with ambient air
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A general and selective iron-catalyzed allylic C-C(vinyl) σ-bond cleavage of allylarenes without the assistance of heteroatoms to give aryl aldehydes is reported. The unstrained carbon-carbon single bond cleavage reaction uses ambient air as the sole oxidant, proceeds efficiently at room temperature, and allows for exceptional functional-group tolerance, which addresses the long-standing challenges of current C-C bond cleavage/functionalization. Notably, the method enables rapid late-stage oxidation of complex bioactive molecules and can be used to expedite syntheses of natural products (vanillin and glucovanillin) from readily available chemical feedstocks.
- Liu, Binbin,Cheng, Lu,Hu, Penghui,Xu, Fangning,Li, Dan,Gu, Wei-Jin,Han, Wei
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p. 4817 - 4820
(2019/05/02)
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- Nitrogen Dioxide Catalyzed Aerobic Oxidative Cleavage of C(OH)–C Bonds of Secondary Alcohols to Produce Acids
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Stable organic nitroxyl radicals are an important class of catalysts for oxidation reactions, but their wide applications are hindered by their steric hinderance, high cost, complex operation, and separation procedures. Herein, NO2 in DMSO is shown to effectively catalyze the aerobic oxidative cleavage of C(OH)?C bonds to form a carboxylic group, and NO2 was generated in situ by decomposition of nitrates. A diverse range of secondary alcohols were selectively converted into acids in excellent yields in this transition-metal-free system without any additives. Preliminary results also indicate its applicability to depolymerize recalcitrant macromolecular lignin. Detail studies revealed that NO2 from nitrates promoted the reaction, and NO2 served as hydrogen acceptor and radical initiator for the tandem oxidative reaction.
- Liu, Mingyang,Zhang, Zhanrong,Song, Jinliang,Liu, Shuaishuai,Liu, Huizhen,Han, Buxing
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supporting information
p. 17393 - 17398
(2019/11/11)
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- o-methoxybenzaldehyde preparation method
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The invention provides an o-methoxybenzaldehyde preparation method, which comprises: 1) mixing a benzaldehyde-based derivative, anhydrous methanol, palladium acetate, an oxidizing agent and an aniline ligand in a solvent, and carrying out a methoxylation reaction under a certain temperature condition to obtain a reaction liquid A; 2) filtering the reaction liquid A, and extracting the obtained filtrate B with an extractant to obtain a lower layer extracting liquid C; 3) drying the extracting liquid C with a drying agent to remove water, filtering, adding silica gel powder to the obtained filtrate D, and carrying out rotary evaporation to remove dichloromethane to obtain a mixture E; and 4) separating and purifying the mixture E through chromatography to obtain o-methoxybenzaldehyde. According to the present invention, the prepared o-methoxybenzaldehyde has high yield and high purity, wherein the yield can reach 67%; and the method has characteristics of simple preparation process, easy operation, short reaction time and substantially increased production efficiency.
- -
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Paragraph 0036-0072
(2019/10/04)
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- A transition metal free expedient approach for the C[dbnd]C bond cleavage of arylidene Meldrum's acid and malononitrile derivatives
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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.
- Suresh, Muthiah,Kumari, Anusueya,Singh, Raj Bahadur
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- Ligand-free Cu(ii)-catalyzed aerobic etherification of aryl halides with silanes: An experimental and theoretical approach
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Owing to their wide occurrence in nature and immense applications in various fields, the synthesis of aryl alkyl ethers has remained a focus of interest. In contrast to the conventional/traditional methods of etherification, herein, we have reported a more efficient method, which is better yielding and more general in application. The etherification of aryl halides by alkoxy/phenoxy silanes was catalyzed by copper acetate in the presence of cesium carbonate and oxygen in DMF at 145 °C. All the as-synthesized compounds were characterized via the 1H-NMR and 13C-NMR spectroscopic techniques. Density functional theory calculations using the B3LYP functional were performed to elucidate the reaction mechanism. The C-O coupling reaction between 2-nitroiodobenzene and tetramethoxysilane was used as a model reaction. The activation energy barriers for the generation of catalytic species (31.6 kcal mol-1) and the σ-bond metathesis (16.0 kcal mol-1), oxidative addition/reductive elimination (20.3 kcal mol-1), halogen atom transfer (19.2 kcal mol-1) and single electron transfer (SET) (29.5 kcal mol-1) mechanisms for the C-O coupling reaction were calculated. Calculations for the key reaction steps were repeated with the B3PW91, PBEH1PBE, wB97XD, CAM-B3LYP and mPW1LYP functionals. The formation of catalytic species via a single electron transfer reaction between tetramethoxysilane and copper acetate, formation of methoxy radicals and methoxylation of copper showed an overall energy barrier of 31.6 kcal mol-1, and therefore is the rate determining step.
- Ahmed, Muhammad Naeem,Ahmad, Khalil,Yasin, Khawaja Ansar,Farooq, Tayyaba,Khan, Bilal Ahmad,Roy, Soumendra K.
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p. 11316 - 11333
(2019/07/31)
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- Enzymatic One-Step Reduction of Carboxylates to Aldehydes with Cell-Free Regeneration of ATP and NADPH
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The direct generation of aldehydes from carboxylic acids is often a challenging synthetic task but undoubtedly attractive in view of abundant supply of such feedstocks from nature. Though long known, biocatalytic carboxylate reductions are at an early stage of development, presumably because of their co-factor requirement. To establish an alternative to whole-cell-based carboxylate reductions which are limited by side reactions, we developed an in vitro multi-enzyme system that allows for quantitative reductions of various carboxylic acids with full recycling of all cofactors and prevention of undesired over-reductions. Regeneration of adenosine 5′-triphosphate is achieved through the simultaneous action of polyphosphate kinases from Meiothermus ruber and Sinorhizobium meliloti and β-nicotinamide adenine dinucleotide 2′-phosphate is reduced by a glucose dehydrogenase. Under these conditions and in the presence of the carboxylate reductases from Neurospora crassa or Nocardia iowensis, various aromatic, heterocyclic and aliphatic carboxylic acids were quantitatively reduced to the respective aldehydes.
- Strohmeier, Gernot A.,Eitelj?rg, Inge C.,Schwarz, Anna,Winkler, Margit
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p. 6119 - 6123
(2019/04/13)
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- Random Mutagenesis-Driven Improvement of Carboxylate Reductase Activity using an Amino Benzamidoxime-Mediated High-Throughput Assay
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Carboxylic acid reductases (CARs) catalyze the direct adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH) dependent reduction of carboxylic acids to their corresponding aldehydes. The identification and improvement of CARs by protein engineering is, however, severely limited by the lack of fast and generic methods to quantify aldehydes. Within this study, we applied a convenient high-throughput assay (HTA) based on amino benzamidoxime (ABAO) that allows the substrate-independent and chemoselective quantification of aldehydes. Random mutagenesis of the well-known CAR from Nocardia iowensis (CARNi) to improve its activity for sterically demanding 2-substituted benzoic acid derivatives was conducted in a KM-dependent fashion, and the HTA applied in the presence of microbial cells. The study identified a hot spot in the active site of CARNi that increased the affinity to 2-methoxybenzoic acid 9-fold upon mutation from glutamine to proline (Q283P). The catalytic performance of CARNiQ283P appeared to be significantly improved also for other substrates such as 2-substituted (2-Cl, 2-Br) as well as 3- and 4-substituted benzoic acids (3-OMe, 4-OMe), and even aliphatic octanoic acid. (Figure presented.).
- Schwendenwein, Daniel,Ressmann, Anna K.,Doerr, Mark,H?hne, Matthias,Bornscheuer, Uwe T.,Mihovilovic, Marko D.,Rudroff, Florian,Winkler, Margit
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supporting information
p. 2544 - 2549
(2019/04/26)
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- Efficient Oxidation of Benzylic and Aliphatic Alcohols Using a Bioinspired Cross-Bridged Cyclam Manganese Complex with H2O2
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The cross-bridged cyclam manganese complex Mn(Me2EBC)Cl2 efficiently catalyzes the oxidation of benzylic and aliphatic alcohols at pH 3 in a mixture of acetonitrile and water at room temperature. The environmentally benign and high oxygen content oxidant H2O2 was adopted. Conversions of the alcohols to the corresponding carbonyl compounds reached 98 % with good to excellent selectivity. In addition, several lignin model compounds were also catalytically oxidized under these conditions, with excellent conversion (up to 96 %) and selectivity (up to 99 %).
- Zhang, Zhan,Khrouz, Lhoussain,Yin, Guochuan,Andrioletti, Bruno
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supporting information
p. 323 - 327
(2018/11/27)
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- Dichlorophenobarbital: An efficient and selective reagent for deoximation of oximes to the carbonyl compounds
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A simple, fast and efficient procedure for the cleavage of a wide of range ketoximes and al-doximes to the corresponding compounds using a safe and low-cost reagent, N,N′-dichlorophenobarbital, under mild reaction conditions at room temperature is described.
- Shiri, Azam,Khoramabadi-Zad, Ahmad,Esmaili-Nezhad, Fateme
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p. 833 - 837
(2018/11/06)
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- Rapid and reversible hydrazone bioconjugation in cells without the use of extraneous catalysts
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The amenability of hydrazone linkages to disassemble via either hydrolysis in mildly acidic aqueous solutions or transimination upon treatment with amine nucleophiles renders them extremely attractive for applications in chemical biology, drug delivery and materials science. Unfortunately, however, the use of hydrazones is hampered by the extremely slow intrinsic rates of their formation from their hydrazine and carbonyl precursors. Consequently, hydrazone formation is typically performed in the presence of a large excess of cytotoxic aniline-based nucleophilic catalysts, rendering hydrazones unsuitable for biological applications that entail their formation in cells. Herein, we report a hydrazine scaffold - o-amino benzyl hydrazine - that rapidly forms hydrazones via intramolecular nucleophilic catalysis, thereby obviating the use of extraneous catalysts. We demonstrate the use of this scaffold for rapid and reversible peptide and protein hydrazone bioconjugation and also for reversible fluorescent labeling of sialylated glycoproteins and choline lipids in mammalian cells.
- Nisal, Rahul,Jose, Gregor,Shanbhag, Chitra,Kalia, Jeet
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supporting information
p. 4304 - 4310
(2018/06/22)
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- Design, synthesis and evaluation of curcumin-based fluorescent probes to detect Aβ fibrils
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Amyloid β fibrillation is an early event in Alzheimer's disease, so its detection is important to understand its roles in Alzheimer's disease. Curcumin, which has poor water solubility, has been reported to have many pharmacological activities including potent anti-amyloid β fibril activity in Alzheimer's disease. In this study, we found that curcumin analogues with the fluorescence property instead of non-inhibition of amyloid β fibrils. The development of new curcumin analogue, Me-CUR (9), as fluorescent switchable probe to detect amyloid β fibrils is described. Me-CUR (9) shows excellent fluorescence, especially higher than ThT (4), in the presence of amyloid β fibrils. These results suggest that Me-CUR (9) can become a useful in vitro amyloid fluorescence sensor for diagnosis of Alzheimer's disease.
- Sato, Taki,Hotsumi, Mayumi,Makabe, Koki,Konno, Hiroyuki
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supporting information
p. 3520 - 3525
(2018/10/15)
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- 5′-Chloro-2,2′-dihydroxychalcone and related flavanoids as treatments for prostate cancer
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Several flavonoids and their biosynthetic precursor chalcones were designed and synthesized to improve the biological effects of the lead compound 2′-hydroxyflavonone against androgen receptor (AR)-dependent transcriptional stimulation. Newly synthesized chalcones 19 and 26 suppressed AR-dependent transcription as well as DHT-dependent growth stimulation at a low micromolar level. These compounds were also effective against ligand-independent constitutively active mutant AR derived from castration-resistant PCa (CRPC). Compounds 19 and 26 showed broad spectrum antiproliferative activity at 5–10 μM against multiple tumor cell lines including androgen-independent and taxane-resistant prostate cancer as well as a multidrug-resistant subline. Mode of action studies suggested that 19 induced sub-G1 accumulation in PC-3 cells by disrupting the microtubule network without affecting cell cycle progression. Furthermore, the in vivo effectiveness of chalcone 19 was confirmed in a xenograft model antitumor assay. Thus, chalcone 19 has the potential to be a bifunctional lead for treatment of AR-dependent PCa at lower doses as well as AR-independent PCa, including CRPC, at higher doses.
- Saito, Yohei,Mizokami, Atsushi,Tsurimoto, Hiroyuki,Izumi, Kouji,Goto, Masuo,Nakagawa-Goto, Kyoko
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supporting information
p. 1143 - 1152
(2018/09/10)
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- NH3?H2O: The Simplest Nitrogen-Containing Ligand for Selective Aerobic Alcohol Oxidation to Aldehydes or Nitriles in Neat Water
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Aqueous ammonia (NH3?H2O) has been shown to serve as the simplest nitrogen-containing ligand to effectively promote copper-catalyzed selective alcohol oxidation under air in water. A series of alcohols with varying electronic and steric properties were selectively oxidized to aldehydes with up to 95 % yield. Notably, by increasing the amount of aqueous ammonia in neat water, the exclusive formation of aryl nitriles was also accomplished with good-to-excellent yields. Additionally, the catalytic system exhibits a high level of functional group tolerance with ?OH, ?NO2, esters, and heteroaryl groups all being amenable to the reaction conditions. This one-pot and green oxidation protocol provides an important synthetic route for the selective preparation of either aldehydes or nitriles from commercially available alcohols.
- Zhang, Guofu,Ma, Danting,Zhao, Yiyong,Zhang, Guihua,Mei, Guangyao,Lyu, Jinghui,Ding, Chengrong,Shan, Shang
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p. 885 - 889
(2018/12/10)
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- Effects of Ancillary Ligands on Redox and Chemical Properties of Ruthenium Coordinated Azoaromatic Pincer
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In this work, the effect of the electronically different ancillary ligands on the overall properties of the RuIIL moiety (L = 2,6-bis(phenylazo)pyridine) in heteroleptic complexes of general formula [RuLQCl]0/+ was investigated. Four different ancillary ligands (Q) with different electronic effects were used to prepare the heteroleptic compounds from the precursor complex, [RuL(CH3CN)Cl2] (1); Q = pcp: 2-(4-chloro-phenylazo)pyridine (strong π-acceptor), [2]+ bpy: 2,2′-bipyridyl (moderate π-acceptor), [3]+ acac-: acetylacetonate (strong σ-donor), 4; and DTBCat2-: 3,5-di-tert-butyl catecholate (strong π-donor), 5. The complexes [2]+, [3]+, 4, and 5 were fully characterized and structurally identified. The electronic structures of these complexes along with their redox partners were elucidated by using a host of physical measurements: nuclear magnetic resonance, cyclic voltammetry, electronic paramagnetic resonance, UV-vis-NIR spectroscopy, and density functional theory. The studies revealed significant effects of the coligands on azo bond lengths of the RuL moiety and their redox behavior. Aerobic alcohol oxidation reactions using these Ru complexes as catalysts were scrutinized. It was found that the catalytic efficiency is primarily controlled by the electronic effect of the coligand. Accordingly, the complex [2]+ (containing a strong π-acceptor coligand, pcp) brings about oxidation efficiently, producing 86% of benzaldehyde. In comparison, however, the complexes 4 and 5 (containing electron donating coligand) furnished only 15-20% of benzaldehyde under identical reaction conditions. Investigations of the reaction mechanism suggest that an unstable Ru-H species is formed, which is transformed to a Ru-hydrazo intermediate by H-walking as reported by Hall et al. (J. Am. Chem. Soc., 2015, 137, 12330). Aerial O2 regenerates the catalyst via oxidation of the hydrazo intermediate.
- Rath, Santi Prasad,Sengupta, Debabrata,Ghosh, Pradip,Bhattacharjee, Rameswar,Chakraborty, Mou,Samanta, Subhas,Datta, Ayan,Goswami, Sreebrata
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p. 11995 - 12009
(2018/09/25)
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- Palladium-Catalyzed Reductive Conversion of Acyl Fluorides via Ligand-Controlled Decarbonylation
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Ligand-controlled non-decarbonylative and decarbonylative conversions of acyl fluorides were developed using a Pd(OAc)2/Et3SiH combination. When tricyclohexylphosphine (PCy3) was used as the ligand, aldehydes were obtained as simple reductive conversion products. The use of 1,2-bis(dicyclohexylphosphino)ethane (Cy2P(CH2)2PCy2, DCPE) as the ligand, however, favored the formation of hydrocarbons, which are decarbonylative reduction products.
- Ogiwara, Yohei,Sakurai, Yuka,Hattori, Hiroyuki,Sakai, Norio
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supporting information
p. 4204 - 4208
(2018/07/29)
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- Reduction of N,N-Dimethylcarboxamides to Aldehydes by Sodium Hydride–Iodide Composite
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A new and concise protocol for selective reduction of N,N-dimethylamides into aldehydes was established using sodium hydride (NaH) in the presence of sodium iodide (NaI) under mild reaction conditions. The present protocol with the NaH-NaI composite allows for reduction of not only aromatic and heteroaromatic but also aliphatic N,N-dimethylamides with wide substituent compatibility. Retention of α-chirality in the reduction of α-enantioriched amides was accomplished. Use of sodium deuteride (NaD) offers a new step-economical alternative to prepare deuterated aldehydes with high deuterium incorporation rate. The NaH-NaI composite exhibits unique chemoselectivity for reduction of N,N-dimethylamides over ketones.
- Chan, Guo Hao,Ong, Derek Yiren,Yen, Zhihao,Chiba, Shunsuke
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