- Highly dispersed cobalt oxide nanoparticles on manganese oxide nanotubes for aerobic oxidation of benzyl alcohol
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Hybrid Co3O4/MnO2 nanotube-based catalysts were prepared by a simple hydrothermal synthesis method. The physico-chemical properties of Co3O4/MnO2 catalyst were then studied by different characterization techniques, namely, SEM, TEM and HR-TEM, XRD, BET surface area, XPS and H2-TPR. The hybrid catalyst showed superior catalytic performance toward benzyl alcohol oxidation than pure MnO2 nanotubes and Co3O4 nanoparticles. The uniform dispersion of Co3O4 nanoparticles, good redox behaviour, the variable oxidation states of manganese and cobalt (Mn3+/4+ or Co3+/2+) as well as the abundance of active surface oxygen species were responsible for such a high catalytic activity.
- Reddy, Velma Ganga,Jampaiah, Deshetti,Chalkidis, Anastasios,Sabri, Ylias M.,Mayes, Edwin L.H.,Bhargava, Suresh K.
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- Aerobic oxidation of alcohols catalyzed by rhodium(iii) porphyrin complexes in water: Reactivity and mechanistic studies
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Selective oxidation of alcohol in water using molecular oxygen as the terminal oxidant is mediated by rhodium porphyrin complexes. Addition of methanol to an aqueous solution of (TSPP)Rh(iii) resulted in observation of the key intermediate porphyrin rhodium(iii) methoxide species. The activation parameters for βC-H elimination of Rh-alkoxide were evaluated.
- Liu, Lianghui,Yu, Mengmeng,Wayland, Bradford B.,Fu, Xuefeng
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- Reversible Redox Activity in Multicomponent Metal-Organic Frameworks Constructed from Trinuclear Copper Pyrazolate Building Blocks
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Inorganic functionalization of metal-organic frameworks (MOFs), such as incorporation of multiple inorganic building blocks with distinct metals into one structure and further modulation of the metal charges, endows the porous materials with significant properties toward their applications in catalysis. In this work, by an exploration of the role of 4-pyrazolecarboxylic acid (H2PyC) in the formation of trinuclear copper pyrazolate as a metalloligand in situ, four new MOFs with multiple components in order were constructed through one-pot synthesis. This metalloligand strategy provides multicomponent MOFs with new topologies (tub for FDM-4 and tap for FDM-5) and is also compatible with a second organic linker for cooperative construction of complex MOFs (1,4-benzenedicarboxylic acid for FDM-6 and 2,6-naphthalenedicarboxylic acid for FDM-7). The component multiplicity of these MOFs originates from PyC's ability to separate Cu and Zn on the basis of their differentiated binding affinities toward pyrazolate and carboxylate. These MOFs feature reversible and facile redox transformations between CuI3(PyC)3 and CuII3(μ-OH)(PyC)3(OH)3 without altering the connecting geometries of the units, thus further contributing to the significant catalytic activities in the oxidation of CO and aromatic alcohols and the decomposition of H2O2. This study on programming multiple inorganic components into one framework and modulating their electronic structures is an example of functionalizing the inorganic units of MOFs with a high degree of control.
- Tu, Binbin,Pang, Qingqing,Xu, Huoshu,Li, Xiaomin,Wang, Yulin,Ma, Zhen,Weng, Linhong,Li, Qiaowei
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- Insight into highly selective photocatalytic oxidation of alcohols by a new trinuclear ruthenium complex with visible light
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A new ligand bearing two tpy moieties and one bpy unit (tpy = 2,2′:6′,2′′-terpyridine; bpy = 2,2′-bipyridine) linked by carbon-carbon single bonds and its corresponding trinuclear ruthenium complex were readily synthesized in high yield, and characterized by 1H NMR spectroscopy, high-resolution electrospray ionization mass spectrometry (HR-ESI/MS) and elemental analysis. The ruthenium complex exhibited moderate catalytic activity towards selective oxidation of alcohols in water with visible light under an air atmosphere. Investigations of UV/vis spectra, electrochemistry and ESI/MS suggested that the catalytic cycle involves two processes, RucII-OH2/Ruc III-OH and RucIII-OH/Ruc IVO. The effective electron transfer from the excited state *[Ru(tpy)2]2+ to [Co(NH3) 5Cl]Cl2 is proposed to be responsible for the good activities of this visible-light-driven system under an air atmosphere.
- Chao, Duobin,Fu, Wen-Fu
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- Polyaniline supported vanadium catalyzed aerobic oxidation of alcohols to aldehydes and ketones
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Polyaniline supported vanadium complex 1 catalyzes efficiently the oxidation of alcohols to aldehydes and ketones in high yields under molecular oxygen in toluene at ca. 100°C. The catalyst 1 can be recycled without loss of activity.
- Reddy, Sabbasani Rajasekhara,Das, Subhabrata,Punniyamurthy
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- Controlled reduction of activated primary and secondary amides into aldehydes with diisobutylaluminum hydride
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A practical method is disclosed for the reduction of activated primary and secondary amides into aldehydes using diisobutylaluminum hydride (DIBAL-H) in toluene. A wide range of aryl and alkyl N-Boc, N,N-diBoc and N-tosyl amides were converted into the corresponding aldehydes in good to excellent yields. Reduction susceptible functional groups such as nitro, cyano, alkene and alkyne groups were found to be stable. Broad substrate scope, functional group compatibility and quick conversions are the salient features of this methodology.
- Azeez, Sadaf,Kandasamy, Jeyakumar,Sabiah, Shahulhameed,Sureshbabu, Popuri
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supporting information
p. 2048 - 2053
(2022/03/31)
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- Visible-Light-Induced Selective C-C Bond Cleavage Reactions of Dimeric β-O-4 and β-1 Lignin Model Substrates Utilizing Amine-Functionalized Fullerene
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Finding a selective and efficient fragmentation process under ambient conditions is pivotal for the generation of fuels and chemical feedstocks from lignoceullosic biomass. In the present study, visible-light and amine-functionalized fullerene-based photocatalyst-promoted photodegradation reactions of dimeric β-O-4 and β-1 lignin model compounds, containing varying numbers of methoxy substituents on the arene ring, were explored to find and develop mild, eco-friendly photochemical techniques for efficient delignification. The results showed that, in contrast to well-known organic photoredox catalysts, amine-functionalized fullerene photocatalyst promoted photochemical reactions of lignin model compounds could lead to more efficient lignin fragmentation reactions through a pathway involving a selective Cα-Cβ bond cleavage process, and in addition, Cα-hydroxyl moiety in lignin model compounds played a significant role in the success of the Cα-Cβ bond cleavage reaction of lignin model substrates.
- Cho, Dae Won,Jang, Hannara,Kim, Min-Ji,Kim, Young-Il,Lim, Dong Hyun,Lim, Suk Hyun,Wee, Kyung-Ryang
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p. 2289 - 2300
(2022/02/07)
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- One-Pot Biocatalytic In Vivo Methylation-Hydroamination of Bioderived Lignin Monomers to Generate a Key Precursor to L-DOPA
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Electron-rich phenolic substrates can be derived from the depolymerisation of lignin feedstocks. Direct biotransformations of the hydroxycinnamic acid monomers obtained can be exploited to produce high-value chemicals, such as α-amino acids, however the reaction is often hampered by the chemical autooxidation in alkaline or harsh reaction media. Regioselective O-methyltransferases (OMTs) are ubiquitous enzymes in natural secondary metabolic pathways utilising an expensive co-substrate S-adenosyl-l-methionine (SAM) as the methylating reagent altering the physicochemical properties of the hydroxycinnamic acids. In this study, we engineered an OMT to accept a variety of electron-rich phenolic substrates, modified a commercial E. coli strain BL21 (DE3) to regenerate SAM in vivo, and combined it with an engineered ammonia lyase to partake in a one-pot, two whole cell enzyme cascade to produce the l-DOPA precursor l-veratrylglycine from lignin-derived ferulic acid.
- Birmingham, William R.,Galman, James L.,Parmeggiani, Fabio,Seibt, Lisa,Turner, Nicholas J.
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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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- Catalytic study of the copper-based magnetic nanocatalyst on the aerobic oxidation of alcohols in water
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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.
- Dehkordi, S. Saeid Saei,Albadi, Jalal,Jafari, Abbas Ali,Samimi, Heshmat Allah
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p. 2527 - 2538
(2021/03/24)
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- Hydrothermal self - sacrificing growth of polymorphous MnO2 on magnetic porous - carbon (Fe3O4@Cg/MnO2): A sustainable nanostructured catalyst for activation of molecular oxygen
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Novel core-shell carbon coated-magnetic (Fe3O4@Cg) nanoparticles supported MnO2 nanosheets (with α- and β-type structure) (Fe3O4@Cg/MnO2) are synthesized through a self-sacrificing templet method. The new hybrid material was fully characterized with Fourier transformed infrared spectroscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, X-ray diffraction analysis (XRD), N2 adsorption/desorption analysis, and transmission electron microscopy; XRD and SEM results affirmed that α- and β-MnO2 nanosheets polymorphs onto the Fe3O4@Cg. The catalytic activity of the as-prepared nanostructured catalyst Fe3O4@Cg/MnO2 has been evaluated in O2 activation for the selective oxidation of benzyl alcohol to benzaldehyde with high conversion; it stability being confirmed by the recycling of the nanostructured catalyst with no obvious loss even after six repeated runs.
- Bakhtiarzadeh, Zohreh,Jang, Ho Won,Karimi, Ziba,Kim, Dokyoon,Msagati, Titus A. M.,Ramakrishna, Seeram,Rostamnia, Sadegh,Rouhani, Shamila,Shokouhimehr, Mohammadreza,Varma, Rajender S.
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- Nickel(II)-Catalyzed Selective (E)-Olefination of Methyl Heteroarenes Using Benzyl Alcohols via Acceptorless Dehydrogenative Coupling Reaction
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An efficient catalytic protocol for the synthesis of selective (E)-olefins by the newly synthesized nickel complexes via greener acceptorless dehydrogenative coupling methodology is presented. Two nickel(II) N, S chelating complexes were structurally characterized with the aid of spectral and single crystal X-ray diffraction methods. Olefination of 2-methylheteroarenes with benzyl alcohols via acceptorless dehydrogenative coupling is achieved by inexpensive nickel(II) catalysts. The present olefination protocol is simple and furnishes the desired 2-alkenylheteroarenes in 35 h and yields in the range of 40–93 %. The dehydrogenative coupling reaction proceeds via the generation of an aldehyde intermediate and produces water and hydrogen as sole by-products. The wide substrate scope of this catalytic reaction covered the synthesis of drug intermediates.
- Balamurugan, Gunasekaran,Ramesh, Rengan
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- 4CzIPN catalyzed photochemical oxidation of benzylic alcohols
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A green photoredox oxidation of benzylic primary and secondary alcohols to aldehydes and ketones with air as an oxidant was reported. The oxidation shows broad substrate scope and excellent selectivity over benzylic alcohols to the aliphatic alcohols. Further mechanistic studies revealed a quinuclidine mediated HAT process, and blue LEDs promoted 4CzlPN (1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene) photoredox cycle were involved in our oxidation.
- Zhang, Heng,Guo, Tianyun,Wu, Mingzhong,Huo, Xing,Tang, Shouchu,Wang, Xiaolei,Liu, Jian
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supporting information
(2021/02/20)
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- Visible light mediated selective oxidation of alcohols and oxidative dehydrogenation of N-heterocycles using scalable and reusable La-doped NiWO4nanoparticles
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Visible light-mediated selective and efficient oxidation of various primary/secondary benzyl alcohols to aldehydes/ketones and oxidative dehydrogenation (ODH) of partially saturated heterocycles using a scalable and reusable heterogeneous photoredox catalyst in aqueous medium are described. A systematic study led to a selective synthesis of aldehydes under an argon atmosphere while the ODH of partially saturated heterocycles under an oxygen atmosphere resulted in very good to excellent yields. The methodology is atom economical and exhibits excellent tolerance towards various functional groups, and broad substrate scope. Furthermore, a one-pot procedure was developed for the sequential oxidation of benzyl alcohols and heteroaryl carbinols followed by the Pictet-Spengler cyclization and then aromatization to obtain the β-carbolines in high isolated yields. This methodology was found to be suitable for scale up and reusability. To the best of our knowledge, this is the first report on the oxidation of structurally diverse aryl carbinols and ODH of partially saturated N-heterocycles using a recyclable and heterogeneous photoredox catalyst under environmentally friendly conditions.
- Abinaya, R.,Balasubramaniam, K. K.,Baskar, B.,Divya, P.,Mani Rahulan, K.,Rahman, Abdul,Sridhar, R.,Srinath, S.
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p. 5990 - 6007
(2021/08/24)
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- Three-Dimensional Radical Covalent Organic Frameworks as Highly Efficient and Stable Catalysts for Selective Oxidation of Alcohols
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With excellent designability, large accessible inner surface, and high chemical stability, covalent organic frameworks (COFs) are promising candidates as metal-free heterogeneous catalysts. Here, we report two 3D radical-based COFs (JUC-565 and JUC-566) in which radical moieties (TEMPO) are uniformly decorated on the channel walls via a bottom-up approach. Based on grafted functional groups and suitable regular channels, these materials open up the application of COFs as highly efficient and selective metal-free redox catalysts in aerobic oxidation of alcohols to relevant aldehydes or ketones with outstanding turn over frequency (TOF) up to 132 h?1, which has exceeded other TEMPO-modified catalytic materials tested under similar conditions. These stable COF-based catalysts could be easily recovered and reused for multiple runs. This study promotes potential applications of 3D functional COFs anchored with stable radicals in organic synthesis and material science.
- Chen, Fengqian,Ding, Jiehua,Fang, Qianrong,Guan, Xinyu,Li, Hui,Qiu, Shilun,Tang, Bin,Valtchev, Valentin,Yan, Yushan,Zhu, Liangkui
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supporting information
p. 22230 - 22235
(2021/09/03)
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- Exploring the Electronic Properties of Extended Benzofuran-Cyanovinyl Derivatives Obtained from Lignocellulosic and Carbohydrate Platforms Raw Materials
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Two series of linear extended benzofuran derivatives associating cyanovinyl unit and phenyl or furan moieties obtained from benzaldehyde-lignocellulosic (Be series) or furaldehyde –saccharide (Fu series) platforms were prepared in order to investigate their emission and electrochemical properties. For the fluorescence in solution and solid states, contrasting results between the two series were demonstrated. For Be series a net aggregation induced emission effect was observed with high fluorescence quantum yield for the solid state. A [2+2] cycloaddition under irradiation at 350 nm was also revealed for one derivative of Be series. In contrast, for Fu series the fluorescence in solution is higher than in the solid state. The X-ray crystallography studies for the compounds reveal the formation of strong π-π stacking for the derivatives without emissive property in the solid state and the presence of essentially lateral contacts for emissive compounds. Taking advantage of the propensity to develop 2D π-stacking mode for the more extended derivative with a central furan cycle, organic field effect transistors presenting hole mobility have been made.
- Ibrahim, Nagham,Moussallem, Chady,Allain, Magali,Segut, Olivier,Gohier, Frédéric,Frère, Pierre
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p. 475 - 482
(2021/03/31)
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- First synthesis of tabamides A–C and their derivatives: In vitro nitric oxide inhibitory activity
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The first synthesis of natural phenolic amides, tabamides A–C (1–3), and their derivatives (4–12) was accomplished using Stobbe condensation and amide coupling reactions as key steps. The in vitro nitric oxide (NO) inhibitory effects of these compounds in LPS-induced RAW-264.7 macrophages were evaluated as an indicator of anti-inflammatory activity. All compounds tested had a concentration-dependent inhibitory effect on NO production by RAW-264.7 macrophages without significant cytotoxicity. Compound 6, a tabamide A derivative (IC50 = 82.6 μM), followed by tabamide A (1, IC50 = 100.7 μM), was the most potent from the series. The present study revealed that tabamide A (1) could be considered as a lead structure to develop NO production-targeted anti-inflammatory agents.
- Damodar, Kongara,Jeon, Sung Ho,Lee, Jeong Tae,Shin, Sooyong
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supporting information
(2021/11/10)
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- Green process synthesis method of 3, 4, 5-trimethoxybenzaldehyde
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The invention discloses a green process synthesis method of 3, 4, 5-trimethoxybenzaldehyde, and relates to the technical field of organic synthesis. The method comprises the following steps: adding syringaldehyde sodium salt into a reaction kettle, adding a solvent and alkali, then starting stirring, then heating to 80-160 DEG C, then adding dimethyl sulfate, carrying out heat preservation stirring reaction for 1-6 hours, then detecting the pH value, if the pH value is less than 10, continuously supplementing alkali and then measuring the pH value until the pH value is more than 10, if the pH value is more than 10, ending the reaction, and filtering to remove sodium sulfate salt, carrying out reduced pressure distillation on the organic layer mother liquor, and recovering the solvent for recycling in the next batch. According to the invention, the yield of the product can be increased to 96.7%-98.2%, and the cost is reduced; reaction conditions are mild, operation is convenient, and the method is suitable for industrial production; the environment-friendly treatment cost is reduced; the generation of a byproduct methanol is reduced, and the safety of industrial production is improved.
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Paragraph 0005; 0015-0022
(2021/09/26)
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- Atomically Dispersed Pt-N3C1Sites Enabling Efficient and Selective Electrocatalytic C-C Bond Cleavage in Lignin Models under Ambient Conditions
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Selective cleavage of C-C linkages is the key and a challenge for lignin degradation to harvest value-added aromatic compounds. To this end, electrocatalytic oxidation presents a promising technique by virtue of mild reaction conditions and strong sustainability. However, the existing electrocatalysts (traditional bulk metal and metal oxides) for C-C bond oxidative cleavage suffer from poor selectivity and low product yields. We show for the first time that atomically dispersed Pt-N3C1sites planted on nitrogen-doped carbon nanotubes (Pt1/N-CNTs), constructed via a stepwise polymerization-carbonization-electrostatic adsorption strategy, are highly active and selective toward Cα-Cβbond cleavage in β-O-4 model compounds under ambient conditions. Pt1/N-CNTs exhibits 99% substrate conversion with 81% yield of benzaldehyde, which is exceptional and unprecedented compared with previously reported electrocatalysts. Moreover, Pt1/N-CNTs using only 0.41 wt % Pt achieved a much higher benzaldehyde yield than those of the state-of-the-art bulk Pt electrode (100 wt % Pt) and commercial Pt/C catalyst (20 wt % Pt). Systematic experimental investigation together with density functional theory (DFT) calculation suggests that the superior performance of Pt1/N-CNTs arises from the atomically dispersed Pt-N3C1sites facilitating the formation of a key Cβradical intermediate, further inducing a radical/radical cross-coupling path to break the Cα-Cβbond. This work opens up opportunities in lignin valorization via a green and sustainable electrochemical route with ultralow noble metal usage.
- Cui, Tingting,Ma, Lina,Wang, Shibin,Ye, Chenliang,Liang, Xiao,Zhang, Zedong,Meng, Ge,Zheng, Lirong,Hu, Han-Shi,Zhang, Jiangwei,Duan, Haohong,Wang, Dingsheng,Li, Yadong
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supporting information
p. 9429 - 9439
(2021/07/19)
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- Merging N-Hydroxyphthalimide into Metal-Organic Frameworks for Highly Efficient and Environmentally Benign Aerobic Oxidation
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Two highly efficient metal-organic framework catalysts TJU-68-NHPI and TJU-68-NDHPI have been successfully synthesized through solvothermal reactions of which the frameworks are merged with N-hydroxyphthalimide (NHPI) units, resulting in the decoration of pore surfaces with highly active nitroxyl catalytic sites. When t-butyl nitrite (TBN) is used as co-catalyst, the as-synthesized MOFs are demonstrated to be highly efficient and recyclable catalysts for a novel three-phase heterogeneous oxidation of activated C?H bond of primary and secondary alcohols, and benzyl compounds under mild conditions. Based on the high efficiency and selectivity, an environmentally benign system with good sustainability, mild conditions, simple work-up procedure has been established for practical oxidation of a wide range of substrates.
- Wang, Man,Liang, Gan,Wang, Yunhao,Fan, Tao,Yuan, Baoling,Liu, Mingxian,Yin, Ying,Li, Liangchun
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supporting information
p. 9674 - 9685
(2021/06/09)
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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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- Nitrosoarene-Catalyzed HFIP-Assisted Transformation of Arylmethyl Halides to Aromatic Carbonyls under Aerobic Conditions
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A rare metal-free nucleophilic nitrosoarene catalysis accompanied by highly hydrogen-bond-donor (HBD) solvent, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), organocatalytically converts arylmethyl halides to aromatic carbonyls. This protocol offers an effective means to access a diverse array of aromatic carbonyls with good chemoselectivity under mild reaction conditions. The activation of arylmethyl halides by HFIP to generate stable carbocation and autoxidation of in situ generated hydroxylamine to nitrosoarene in the presence of atmospheric O2 are the keys to success.
- Pradhan, Suman,Sharma, Vishali,Chatterjee, Indranil
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supporting information
p. 6148 - 6152
(2021/08/03)
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- Hydrogenation of plant polyalkoxybenzene derivatives: convenient access to coenzyme Q0 analogues
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A technologically advanced protocol has been developed for converting plant allyl(polyalkoxy)benzenes to methyl- and propyl(polyalkoxy)benzenes being intermediates in the syntheses of coenzyme Q0 analogues. The key stage of allyl and benzaldehyde moieties hydrogenation was carried out in a periodical autoclave mode on highly porous ceramic block Pd-catalysts. These catalysts possess large surface area, low hydraulic resistance, significant thermal and mechanical stabililty, multiple cycling and easy regeneration, which can dramatically reduce Pd consumption.
- Khrustalev, Victor N.,Muravsky, Egor A.,Semenov, Victor V.,Shinkarev, Ilia Yu.,Varakutin, Alexander E.
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p. 599 - 601
(2020/10/18)
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- Solvent-free, microwave assisted oxidation of alcohols with 4-hydroxypyridinium chlorochromate functionalized silica gel
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4-Hydroxypyridinium chlorochromate functionalized silica gel was found to be an efficient and reusable oxidant for the very fast oxidation of primary and secondary alcohols to the corresponding carbonyl compounds under solventfree conditions and microwave irradiation in excellent yields.
- AHMADI, Sayed Ali,GHALEHBANDI, Shermineh Sadat,GHAZANFARI, Dadkhoda,SHEIKHHOSSEINI, Enayatollah
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p. 283 - 289
(2020/10/06)
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- Fluorinated benzylidene indanone exhibits antiproliferative activity through modulation of microtubule dynamics and antiangiogenic activity
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The application of fluorine in drug design has been understood significantly by the medicinal chemists in recent years. Modulation of tubulin-microtubule dynamics is one of the most effective targets for cancer chemotherapeutics. A logically designed and identified lead compound, fluorinated benzylidene indanone 1 has been extensively evaluated for cancer pharmacology. It occupied colchicine binding pocket acting as microtubule destabilizer and induced a G2/M phase arrest in MCF-7 cells. Compound 1 exerted an antiangiogenic effect in MCF-7 cells by down-regulating Vascular Endothelial Growth Factor (VEGF) and Hypoxia Inducible Factor-α (HIF-α). In in-vivo efficacy in C3H/Jax mice mammary carcinoma model, benzylidene indanone 1 reduced tumour volumes by 48.2%. Further in acute oral toxicity studies compound 1 was well tolerated and safe up to 1000 mg/kg dose in Swiss albino mice. The fluorinated benzylidene indanone 1, a new chemical entity (NCE) can further be optimized for better efficacy against breast adenocarcinoma.1
- Chanda, Debabrata,Fatima, Eram,Fatima, Kaneez,Khan, Feroz,Luqman, Suaib,Negi, Arvind S.,Shanker, Karuna,Shukla, Aparna,Singh, Aastha,Singh, Arjun,Srivastava, Ankita
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- Mechanistic insight into concerted proton-electron transfer of a Ru(IV)-oxo complex: A possible oxidative asynchronicity
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We have thoroughly investigated the oxidation of benzyl alcohol (BA) derivatives by a RuIV(O) complex (RuIV(O)) in the absence or presence of Br?nsted acids in order to elucidate the proton-coupled electron-transfer (PCET) mechanisms in C-H oxidation on the basis of a kinetic analysis. Oxidation of BA derivatives by RuIV(O) without acids proceeded through concerted proton-electron transfer (CPET) with a large kinetic isotope effect (KIE). In contrast, the oxidation of 3,4,5-trimethoxy- BA ((MeO)3-BA) by RuIV(O) was accelerated by the addition of acids, in which the KIE value reached 1.1 with TFA (550 mM), indicating an alteration of the PCET mechanism from CPET to stepwise electron transfer (ET) followed by proton transfer (PT). Although the oxidized products of BA derivatives were confirmed to be the corresponding benzaldehydes in the range of acid concentrations (0-550 mM), a one-electron-reduction potential of RuIV(O) was positively shifted with increases in the concentrations of acids. The elevated reduction potential of RuIV(O) strongly influenced the PCET mechanisms in the oxidation of (MeO)3-BA, changing the mechanism from CPET to ET/PT, as evidenced by the driving-force dependence of logarithms of reaction rate constants in light of the Marcus theory of ET. In addition, dependence of activation parameters on acid concentrations suggested that an oxidative asynchronous CPET, which is not an admixture of the CPET and ET/PT mechanisms, is probably operative in the boundary region (0 mM [TFA] 50 mM) involving a one-protoninteracted RuIV(O) H+ as a dominant reactive species.
- Kojima, Takahiko,Kotani, Hiroaki,Shimomura, Hinatsu,Ikeda, Kei,Ishizuka, Tomoya,Shiota, Yoshihito,Yoshizawa, Kazunari
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p. 16982 - 16989
(2020/11/09)
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- Design and development of natural and biocompatible raffinose-Cu2O magnetic nanoparticles as a heterogeneous nanocatalyst for the selective oxidation of alcohols
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Natural polymers are recently playing a vital role as a support for the noble metals. In the present study, raffinose from the classes of oligosaccharide polymer with a high capacity of magnetization was used as active support for the copper metal. The copper immobilized on the raffinose-based magnetic nanoparticles (MNPs) which can be used as a recyclable heterogeneous nanocatalyst for the selective oxidation of primary benzyl alcohols (PBA) to benzaldehyde (BAD) derivatives. The morphology and structure of the recoverable magnetic nanocatalyst were characterized using different microscopic and spectroscopic techniques including FT-IR, GC, VSM, XRD, TEM, TGA, FESEM and EDS analyses. Also, the optimum conditions of co-reactant, reaction time, oxidant, temperature and amount of the nanocatalyst for oxidation reaction were investigated. Moreover, the Fe3O4?raffinose-Cu2O NPs had a significant effect to enhance yield and reduce the reaction time.
- Eivazzadeh-Keihan, Reza,Esmaeili, Mir Saeed,Ghafuri, Hossein,Maleki, Ali,Varzi, Zahra
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- Visible-light-induced C-C bond cleavage of lignin model compounds with cyanobenziodoxolone
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The catalytic degradation of lignin to value-added chemicals has received considerable attention over the past decade. Photocatalysis provides promising approaches to enable previously inaccessible transformations. However, examples of the visible-light promoted degradation of lignin are still limited. In this work, the visible-light-induced selective C-C bond cleavage of β-O-4 lignin model compounds has been disclosed via β-scission of in situ generated alkoxy radical intermediates. With cyanobenziodoxolone as the oxidant, a variety of substrates could be transformed into aldehydes in moderate to good yields. In addition, unexpected acetal esters which could conveniently furnish formaldehyde and phenols by alcoholysis were observed.
- Zheng, Ming,Huang, Yan,Zhan, Le-Wu,Hou, Jing,Li, Bin-Dong
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- Copper-Mediated Conversion of Complex Ethers to Esters: Enabling Biopolymer Depolymerisation under Mild Conditions
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Selective processing of the β-O-4 unit in lignin is essential for the efficient depolymerisation of this biopolymer and therefore its successful integration into a biorefinery set-up. An approach is described in which this unit is modified to incorporate a carboxylic ester with the goal of enabling the use of mild depolymerisation conditions. Inspired by preliminary results using a Cu/TEMPO/O2 system, a protocol was developed that gave the desired β-O-4-containing ester in high yield using certain dimeric model compounds. The optimised reaction conditions were then applied to an oligomeric lignin model system. Extensive 2D NMR analysis demonstrated that analogous chemistry could be achieved with the oligomeric substrate. Mild depolymerisation of the ester-containing oligomer delivered the expected aryl acid monomer.
- Xiao, Ganyuan,Montgomery, James R. D.,Lancefield, Christopher S.,Panovic, Isabella,Westwood, Nicholas J.
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p. 12397 - 12402
(2020/09/07)
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- Method for preparing aldehyde compounds through photocatalytic oxidation cracking β - hydroxyl compound C-C bond
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The invention provides a method for preparing aldehydes from C-C bonds of beta-hydroxy compounds by photocatalytic oxidative cracking. According to the method, the beta-hydroxy compounds are taken asa substrate, oxygen-containing gas is taken as an oxygen source, and C-C bond cracked products, namely, corresponding aldehydes can be generated under illumination in presence of a catalyst. The conditions are mild, the oxidation efficiency and the product yield are high, and the oxygen-containing gas is taken as the oxygen source under the illumination condition, so that the method is economical,environmentally friendly and green, meets the strategy of sustainable developed energy and has broad application prospect.
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Paragraph 0058-0061; 0064-0067; 0070-0077
(2020/07/29)
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- Differences in the Mechanisms of MnO2Oxidation between Lignin Model Compounds with the p-Hydroxyphenyl, Guaiacyl, and Syringyl Nuclei
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The purpose of this study was to examine how the rate and mechanism of MnO2 oxidation differ between the p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) types of simple nonphenolic lignin model compounds as well as the p-ethylphenyl (E) type compounds. The oxidation was conducted using an excess amount of MnO2 in a sulfate buffer solution at a pH value of 1.5 at room temperature. MnO2 oxidized at least the G and S nuclei, although it commonly oxidizes alcohols present at the benzyl position. The oxidation rates of the benzyl alcohol derivatives were in the order of G- > S- ? H- > E-type, which suggests that the rates are determined by the electronic effects of their methoxy and ethyl functional groups on not only their benzyl positions but also their aromatic π-electron systems. The kinetic isotope effect was observed in the MnO2 oxidations of the same derivatives deuterated at their benzyl hydroxymethyl groups. The observed magnitudes were in the order of E- ? H- > G- ? S-type, suggesting that the contribution of oxidation of their aromatic nuclei, which is another reaction mode of the oxidation of their benzyl positions, increases in the reverse order.
- Sun, Shirong,Akiyama, Takuya,Yokoyama, Tomoya,Matsumoto, Yuji
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p. 6819 - 6825
(2020/07/02)
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- Aerobic oxidation of alcohols with air catalyzed by decacarbonyldimanganese
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The oxidation of alcohols to carbonyl compounds using air as the terminal oxidant is highly desirable. As described in previous reports, the abstraction of α-H of the alcohol is the most important step, and it typically requires not only a metal catalyst but also complex ligands, co-catalysts and bases. Herein, we report a practical and efficient method for the oxidation of primary alcohols, secondary alcohols, 1,2-diols, 1,2-amino alcohols, and other α-functionalized alcohols using a commercially available catalyst, Mn2(CO)10, and no additives. Preliminary mechanistic studies indicated that an alkoxyl radical intermediate existed in our system, and a plausible mechanism consistent with the experimental results and literature was proposed.
- Meng, Shan-Shui,Lin, Li-Rong,Luo, Xiang,Lv, Hao-Jun,Zhao, Jun-Ling,Chan, Albert S. C.
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supporting information
p. 6187 - 6193
(2019/11/20)
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- Reactivity and Catalytic Activity of Homobimetallic Vanadium(V) Complex Derived from Bis(5-chlorosalicylaldehyde)oxaloyldihydrazone Ligand
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Homobimetallic vanadium(V) complex of the composition [(CH3)2NH2+]2[(VO2)2(sloxCl)].4H2O was synthesized from the reaction of V2O5 with bis(5-chlorosalicylaldehyde)oxaloyldihydrazone ligand in a 1:1 molar ratio in methanol. The structure of the complex was established by X-ray crystallography. Reactivity of the complex with H2O2 leads to bis (monooxidoperoxidovanadate(V)) [{VO(O2)}2(sloxCl)]2? formation and with HCl, oxidohydroxido complex of composition [(VO (OH)(sloxCl)]2? was formed. Binding interaction of the complex was also investigated toward protein (BSA) and it was found to be 2.21 x 108?M?1. The catalytic activity of the complex in the oxidation of alcohols and oxidative bromination of some organic substrates was also studied, and it showed a great potent as a catalyst.
- Syiemlieh, Ibanphylla,Asthana, Mrityunjaya,Lal, Ram A.
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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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- Rationally designed molecules for resurgence of cyanide mitigated cytochrome c oxidase activity
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Cytochrome c oxidase (CcOX) containing binuclear heme a3-Cu B centre (BNC) mechanises the process of electron transfer in the last phase of cellular respiration. The molecular modelling based structural analysis of CcOX – heme a3-Cu B complex was performed and the disturbance to this complex under cyanide poisoning conditions was investigated. Taking into consideration the results of molecular docking studies, new chemical entities were developed for clipping cyanide from the enzyme and restoring its normal function. It was found that the molecules obtained by combining syringaldehyde, oxindole and chrysin moieties bearing propyl/butyl spacing groups occupy the BNC region and effectively remove cyanide bound to the enzyme. The binding constant of compound 2 with CN– was 2.3 × 105 M?1 and its ED50 for restoring the cyanide bound CcOX activity in 10 min was 16 μM. The compound interacted with CN– over the pH range 5–10. The comparison of the loss of enzymatic activity in the presence of CN– and resumption of enzymatic activity by compound 2 mediated removal of CN– indicated the efficacy of the compound as antidote of cyanide.
- Kaur, Harpreet,Singh, Palwinder
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p. 229 - 240
(2018/11/06)
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- Organosuperbase dendron manganese complex grafted on magnetic nanoparticles; heterogeneous catalyst for green and selective oxidation of ethylbenzene, cyclohexene and oximes by molecular oxygen
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Magnetic Fe3O4 nanoparticles as a support were modified with an amino-terminated organosilicon and cyanoric choloride ligands. The novel manganese complex was grafted on modified magnetic support (Mn(II)-Met@MMNPs). The nanocatalyst structure, particle size, morphology and surface properties was well characterized by elemental analysis, ICP-AES, AAS, EDS, FT-IR, SEM, TEM, DLS, VSM, TGA, XRD and XPS. In order to develop an effective heterogeneous nanocatalyst for eco-friendly aerobic, highly active and selective catalytic reactions, synthesized nanocatalyst was applied in oxidation of various organic compounds. The catalytic performance of the manganese nanocatalyst in the aerobic oxidation of ethylbenzene (EB), cyclohexene (CYHE) and various aldoximes and ketoxime were studied. Selective aerobic oxidation of EB and CYHE and various oximes were catalyzed by the Mn-nanocatalyst using N-hydroxyphthalimide (NHPI) with molecular oxygen as the green oxidant without the need of any reducing agent, and respectively the acetophenone (AcPO) as a benzylic product, 2-cyclohexene-1-one (CYHE[dbnd]O) as an allylic product and corresponding carbonyl compounds were obtained. The oxidation process has been optimized for Mn-nanocatalyst by considering the effect of different parameters such as the ratio and amount of Mn-nanocatalyst/NHPI, reaction time and solvent for achieving maximum conversion and selectivity to products. Due to their significant low cost, informal preparation, easy magnetically separation from reaction mixture, excellent catalytic performance, simple recovery and reusability without any metal leaching, the Mn-nanocatalyst has huge application prospect in selective and green oxidation process.
- Faraji, Ali Reza,Ashouri, Fatemeh,Hekmatian, Zahra,Heydari, Somayyeh,Mosazadeh, Sima
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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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- Method for depolymerizing lignin into aromatic compound through photocatalysis (by machine translation)
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The invention relates to a method, for depolymerizing lignin into an aromatic compound by photocatalysis. Belong to application chemistry technical field. The method uses lignin as a reaction substrate, and under the excitation of a light source, under the catalysis of a light source, the C-C bond is selectively cracked under the assistance of a base and a hydrogen donor, and the molar ratio of the reaction substrate, photocatalyst, base, and hydrogen donor is 100: (0.5~10) 1~20: (1~20), and the reaction temperature is room temperature, and the reaction substrate is a reaction substrate. The reaction time was 6~24 hours. The method has the advantages, such as simple reaction steps, mild reaction conditions, high bond breaking selectivity 100%, high yield, atom efficiency, environmental protection and the like, has the functions, is high in selectivity, and efficiently degrades the lignin, and is beneficial to large-scale industrial production and application of lignin degradation and the like. (by machine translation)
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Paragraph 0047-0052
(2019/07/29)
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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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- Production of (S)-β-Nitro Alcohols by Enantioselective C?C Bond Cleavage with an R-Selective Hydroxynitrile Lyase
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Hydroxynitrile lyase (HNL)-catalysed stereoselective synthesis of β-nitro alcohols from aldehydes and nitroalkanes is considered an efficient biocatalytic approach. However, only one S-selective HNL—Hevea brasiliensis (HbHNL)—exists that is appropriate for the synthesis of (S)-β-nitro alcohols from the corresponding aldehydes. Further, synthesis catalysed by HbHNL is limited by low specific activity and moderate yields. We have prepared a number of (S)-β-nitro alcohols, by kinetic resolution with the aid of an R-selective HNL from Arabidopsis thaliana (AtHNL). Optimization of the reaction conditions for AtHNL-catalysed stereoselective C?C bond cleavage of racemic 2-nitro-1-phenylethanol (NPE) produced (S)-NPE (together with benzaldehyde and nitromethane, largely from the R enantiomer) in up to 99 % ee and with 47 % conversion. This is the fastest HNL-catalysed route known so far for the synthesis of a series of (S)-β-nitro alcohols. This approach widens the application of AtHNL for the synthesis not only of (R)- but also of (S)-β-nitro alcohols from the appropriate substrates. Without the need for the discovery of a new enzyme, but rather by use of a retro-Henry approach, it was used to generate a number of (S)-β-nitro alcohols by taking advantage of the substrate selectivity of AtHNL.
- Rao, D. H. Sreenivasa,Padhi, Santosh Kumar
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p. 371 - 378
(2019/01/08)
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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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- Fe(NO3)3/2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ): An efficient catalyst system for selective oxidation of alcohols under aerobic conditions
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A practical and efficient catalyst system for the oxidation of alcohols to carbonyl compounds using catalytic amounts of DDQ and Fe(NO3)3 with air as the environmentally benign oxidant has been developed. A variety of benzylic, heterocyclic, allylic and propargylic alcohols were smoothly converted into aldehydes or ketones in good to excellent yields. In case of large-scale reaction for the oxidation of benzyl alcohol, benzaldehyde was obtained in 93% isolated yield. Moreover, a possible reaction mechanism was proposed.
- Hu, Yongke,Chen, Lei,Li, Bindong
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- Water soluble new bimetallic catalyst [CuZn(bz)3(bpy)2]PF6 in hydrogen peroxide mediated oxidation of alcohols to aldehydes/ketones and C-N functional groups
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A new heterobimetallic [CuZn(bz)3(bpy)2]PF6 has been synthesized from commercially available starting materials. Its structure has been established by molar conductance, magnetic moment, IR, electronic, ESR and X-ray crystallography. Its catalysis has been established in hydrogen peroxide mediated oxidation of alcohols to aldehydes and ketones and direct formation of oximes.
- Syiemlieh, Ibanphylla,Asthana, Mrityunjaya,Asthana, Sharad K.,Kurbah, Sunshine D.,Koch, Angira,Lal, Ram A.
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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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- Photocatalytic oxidation of arylalcohols to aromatic aldehydes promoted by hydroxyl radicals over a CoP/CdS photocatalyst in water with hydrogen evolution
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Cobalt phosphide (CoP) combined with CdS was employed as a photocatalyst to oxidize arylalcohols into aromatic aldehydes or ketones in water. This was accompanied by the reduction of water, and the quantitative yield of hydrogen evolution was much higher than the chemical equivalent of hydrogen gas. Electron spin resonance spectroscopy and quenching experiments demonstrated that hydroxyl free radicals, originating from water splitting, promoted the oxidation of arylalcohols, while the holes in the valence band of the photocatalyst were reduced by the -OH and organic substrates. The overall reaction generates high-value-added organics. This photocatalytic reaction is atom-economical, in accordance with the concept of sustainable development.
- Xu, Yong,Zeng, Ling-Zhen,Fu, Zi-Cheng,Li, Cong,Yang, Zhi,Chen, Yong,Fu, Wen-Fu
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p. 2540 - 2545
(2018/05/30)
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- CO2-Catalyzed oxidation of benzylic and allylic alcohols with DMSO
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CO2-catalyzed transition-metal-free oxidation of alcohols has been achieved. Earlier, several methodologies have been explored for alcohol oxidations based on transition-metal catalysts. However, owing to the cheaper price, easy separation and nontoxicity, transition-metal-free systems are in high demand to the pharmaceutical industries. For this reason, various primary and secondary alcohols have been selectively oxidized to the corresponding carbonyl compounds using CO2 as a catalyst in the presence of different functional groups such as nitrile, nitro, aldehyde, ester, halogen, ether, and so on. At the end, transition-metal-free syntheses of pharmaceuticals have also been achieved. Finally, the role of CO2 has been investigated in detail, and the mechanism is proposed on the basis of experiments and DFT calculations.
- Riemer, Daniel,Mandaviya, Bhavdip,Schilling, Waldemar,G?tz, Anne Charlotte,Kühl, Torben,Finger, Markus,Das, Shoubhik
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p. 3030 - 3034
(2018/04/14)
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- Metal-Free catalyst for visible-light-induced oxidation of unactivated alcohols using Air/Oxygen as an oxidant
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9-Fluorenone acts as a metal-free and additive-free photocatalyst for the selective oxidation of primary and secondary alcohols under visible light. With this photocatalyst, a plethora of alcohols such as aliphatic, heteroaromatic, aromatic, and alicyclic compounds has been converted to the corresponding carbonyl compounds using air/oxygen as an oxidant. In addition to these, several steroids have been oxidized to the corresponding carbonyl compounds. Detailed mechanistic studies have also been achieved to determine the role of the oxidant and the photocatalyst for this oxidation.
- Schilling, Waldemar,Riemer, Daniel,Zhang, Yu,Hatami, Nareh,Das, Shoubhik
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p. 5425 - 5430
(2018/05/15)
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- Activation of Molecular Oxygen Using Durable Cobalt Encapsulated with Nitrogen-Doped Graphitic Carbon Shells for Aerobic Oxidation of Lignin-Derived Alcohols
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It has long been a challenge for activating O2 by transition-metal nanocatalysts, which might lose activity due to strong tendency for oxidation. Herein, O2 could be activated by durable encapsulated cobalt nanoparticles (NPs) with N-doped graphitic carbon shells (Co@N-C), but not by encapsulated cobalt NPs with graphitic carbon, exposed cobalt NPs supported on activated carbon, or N-doped carbon. Electron paramagnetic resonance, real-time in situ FTIR spectroscopy, and mass spectrometry measurements demonstrated the generation of the highly active superoxide radical, O2.?. This unique ability enables Co@N-C to afford an excellent catalytic performance in model aerobic oxidation of monomeric lignin-derived alcohols. Further analysis elucidated that encapsulated cobalt and nitrogen-doped graphitic carbon might contribute to the capacity through influencing the electronic properties of outer layers. Moreover, through isolation by N-doped graphitic carbon shells, the inner metallic cobalt NPs are inaccessible in term of either alcohols or oxygenated products, and a distinctive resistance to leaching and agglomeration has been achieved.
- Sun, Yuxia,Ma, Hong,Luo, Yang,Zhang, Shujing,Gao, Jin,Xu, Jie
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p. 4653 - 4661
(2018/03/01)
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- Photoredox-Catalyzed Decarboxylative Oxidation of Arylacetic Acids
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A photoredox-catalyzed decarboxylative oxidation of arylacetic acids, which are privileged scaffolds in pharmaceuticals, is reported herein. The established method is operationally simple and a variety of substrates are applicable, providing rapid access to dehomologated bioisosteres of common pharmaceuticals.
- Sakakibara, Yota,Cooper, Phillippa,Murakami, Kei,Itami, Kenichiro
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supporting information
p. 2410 - 2413
(2018/06/04)
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- Synthetic method for drug intermediate 3,4,5-trimethoxybenzaldehyde
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The invention discloses a synthetic method for the drug intermediate 3,4,5-trimethoxybenzaldehyde. The synthetic method comprises the following steps: adding 2,6-dibromo-3,4,5-trimethoxy-benzyl alcohol and a hexane solution into a reaction vessel, controlling a solution temperature, adding an aqueous solution and potassium peroxydisulfate, and continuing a reaction; and then adding a sodium nitrate solution and chloro-iridic acid powder, raising the temperature, continuing the reaction, adding a sodium chloride solution, lowering the temperature, carrying out standing to realize layering of the obtained solution, carrying out washing with biphenyl solution, carrying out recrystallization in an o-dinitrobenzene solution, and then carrying out dehydration with a dehydrating agent to obtain the finished 3,4,5-trimethoxybenzaldehyde.
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Paragraph 0012; 0015-0026
(2018/07/30)
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- Three-dimensional composite of Co3O4 nanoparticles and nitrogen-doped reduced graphene oxide for lignin model compound oxidation
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A three-dimensional composite of Co3O4 nanoparticles and nitrogen-doped reduced graphene oxide (3D Co3O4/N-rGO) with a unique 3D porous structure was prepared, and its catalytic activity in lignin model compound oxidation was explored. The 3D Co3O4/N-rGO composite exhibits improved catalytic performance as compared to Co3O4 nanoparticles or 3D N-rGO in the oxidation of lignin model compounds. The higher catalytic activity of the 3D Co3O4/N-rGO composite is attributed to the combination of its porous structural features, large surface area that is provided by the 3D N-rGO matrix, and active Co3O4 nanoparticles doped on the N-rGO surface. The structural features of the 3D Co3O4/N-rGO are beneficial to reactant and product diffusion and transportation, and also are helpful in preventing aggregation of Co3O4 nanoparticles. In addition, the introduction of N atoms in rGO is also favorable for the formation of active oxygen species for the oxidation of model compounds. Given the high activity and the easy recovery from the reaction system, the 3D Co3O4/N-rGO composite should be applicable to non-noble metal catalytic systems for lignin model compounds.
- Zhang, Jiali,Zhang, Fangwei,Guo, Shouwu,Zhang, Jingyan
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p. 11117 - 11123
(2018/07/05)
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- Method for preparing aldehyde by oxidizing primary alcohol
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The invention discloses a method for preparing aldehyde by catalytic oxidation of primary alcohol. The method comprises the steps that the primary alcohol as shown in a formula (I) or (III) is taken as a raw material, copper salt is taken as a catalyst, air is taken as an oxidizing agent, TEMPO (2,2,6,6-tetramethyl-1-piperidine-N-oxyl compound) is taken as a pro-oxygenic agent, ammonium hydroxide is taken as a co-catalyst and solvent, the primary alcohol, the copper salt, the air, the TEMPO and the ammonium hydroxide are mixed uniformly and react for 9 to 24 hours at the temperature of 60 to 120 DEG C; after the reaction, reaction liquid is subjected to aftertreatment to obtain aldehyde as shown in a formula (II) or (IV). The method has the advantages of high reaction rate and yield, low cost, convenience in operation and safety in reaction. The whole process is environmental friendly and free of pollution.
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Paragraph 0026; 0027; 0028; 0029; 0030; 0111; 0112-0115
(2017/07/21)
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- Synthesis of smart bimetallic nano-Cu/Ag@SiO2 for clean oxidation of alcohols
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Here, we have demonstrated the synthesis and characterization of silica supported bimetallic copper/silver nanoparticles (Cu/Ag@SiO2 NPs) and their application in the clean oxidation of benzoins/benzyl alcohols in the presence of tert-butyl hydroperoxide as a mild oxidant. All the reactions were very fast (4 h) and high yielding (95-99%), and the Cu/Ag@SiO2 NPs were very stable under the reaction conditions. The catalyst was recovered simply by filtration and reused eight times without loss of its catalytic performance.
- Saha, Arijit,Payra, Soumen,Banerjee, Subhash
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supporting information
p. 13377 - 13381
(2017/11/27)
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- Nanorods of FeVO4: An efficient heterogeneous catalyst for chemoselective oxidation of benzylic alcohols
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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.
- Heydari, Akbar,Sheykhan, Mehdi,Sadeghi, Masoud,Radfar, Iman
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p. 248 - 255
(2017/08/10)
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