- 1,4-DIAMINO-1,4-DIDEOXY-D-GALACTITOL AND 1,5-DIAMINO-1,5-DIDEOXY-L-ALTRITOL
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The mesyloxy group of 1-azido-1-deoxy-4-O-mesyl-D-glucitol could be displaced by azide, in the 2,3:4,5-di-O-isopropylidene derivative 4 or tetraacetate, yielding, after removal of the protecting groups, 1,4-diazido-1,4-dideoxy-D-galactitol (7).The 2,3- (10( and 5,6-O-isopropylidene derivative (13) of 7 gave, on mesylation, the corresponding 5,6- (11) and 2,3-dimesylate (15), respectively.Treatment of 11 with hydrochloric acid yielded 3,6-anhydro-1,4-diazido-1,4-dideoxy-5-O-mesyl-D-galactitol, whereas 15 gave the corresponding 5,6-diol which was converted with base into 2,6-anhydro-1,4-diazido-1,4-dideoxy-3-O-mesyl-D-talitol.Cleavage of the 5,6-O-isopropylidene group of 4 gave 1-azido-1-deoxy-2,3-O-isopropylidene-4-O-mesyl-D-glucitol, which could be converted via the corresponding 4,5-epoxide into 1,5-diazido-1,5-dideoxy-2,3-O-isopropylidene-L-altritol (25).The 6-p-nitrobenzoates of 25 and 13 are derivatives suitable for the synthesis of sorbistin analogues.Reductionof the corresponding deprotected diazides afforded the title compound.
- Kuszmann Janos
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- Studies on a dithiane-protected benzoin photolabile safety catch linker for solid-phase synthesis
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Substituted benzoinyl systems 8a-g, differing either in the substitution pattern, type of resin matrix used, or resin loading capacity, were prepared and the kinetics of their photolytic cleavage of Fmoc-β-alanine examined on resin. The linker systems 6a-g were assembled in near-quantitative yield using Corey-Seebach dithiane addition. The dithiane group that serves as a safety catch against premature photoreaction was removed by either oxidation or alkylation. Analytical methods that include FTIR and 13C gel-phase NMR spectroscopy were used for rapid reaction monitoring and sample characterization on resin. A survey of different substituted systems 8c-f for releasing Fmoc-β-alanine confirmed that the 3-alkoxybenzoin linker photocleaves most rapidly to give the highest yield (τ(1/2) = 6.7 min; 98% yield). Lowering the resin loading from 0.59 mmol/g in 8a to 0.26 mmol/g in 8b improved the cleavage kinetics to τ(1/2) = 2.6 min, 92% yield. Tentagel resin 8g exhibits similar photocleavage kinetics in both organic and aqueous media and when compared to the polystyrene counterpart, 8a. The 3- alkoxybenzoin linker 6a was also loaded with aryl carboxylic acids (12h,i) and hindered Fmoc-protected amino acids (12j-l) with varying degrees of success (57-100%) and dithiane deprotected (70-80%, 13h-1) followed by photocleavage with comparable efficiencies (8993% after 60 min).
- Hong Boon Lee,Balasubramanian
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- Synthesis of 18O-labelled alcohols from unlabelled alcohols
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The synthesis of primary, secondary and tertiary 18O-enriched alcohols from readily available 16O-alcohols via a Mitsunobu esterification and hydrolysis is described. The method is further exemplified in the labelling of the active pharmaceutical ingredient, dropropizine and is shown to be tolerant of modern, separation friendly Mitsunobu reagents. This journal is
- Beddoe, Rhydian H.,Edwards, Daniel C.,Goodman, Louis,Sneddon, Helen F.,Denton, Ross M.
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- 2-(5-Arylterphenyl-4-yl)quinolines from 2-methylquinoline and 1-(het)aryl-3-phenylprop-2-yn-1-ones in just a one step: A miracle of molecular interplay
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2-Methylquinoline reacts with 1-(het)aryl-3-phenylprop-2-yn-1-ones under mild transition metal-free conditions (55–60 °C, 20 mol% KOH, H2O, MeCN) to afford 2-{5’-(het)aryl[1,1’: 3’,1”]terphenyl-4’-yl}quinolines in up to 35% yield. The reaction likely proceeds via the intermediate 1,3-dipole followed by the double nucleophilic vinylation of the methyl group with two molecules of ynone and subsequent elimination of (het)arenecarboxylic acid.
- Trofimov, Boris A.,Belyaeva, Kseniya V.,Nikitina, Lina P.,Afonin, Andrei V.,Vashchenko, Alexander V.
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- Sodium percarbonate: A convenient reagent for the thermal and sonic oxidative cleavage of α-haloketones
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Sodium percarbonate has been found to be a mild and effective reagent for the oxidative cleavage of α-haloketones to carboxylic acids. Furthermore, the reactions are dramatically accelerated in the presence of ultrasound with significant enhancement in yields.
- Yang,Cao,Kabalka
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- Novel rearrangement of 4-aroyloxy-3-bromomethyl-2-isoxazolines to 3-aroyloxymethylisoxazoles and a mechanistic study
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Treatment of 4-aroyloxy-3-bromomethyl- and 4-aroyloxy-3-aroyloxymethyl-2-isoxazolines with NaHCO3 in DMF at 120°C gave 3-aroyloxymethylisoxazoles in moderate to good yields. A concerted mechanism is proposed to explain the formation of the rearrangement products. (C) 2000 Elsevier Science Ltd.
- Chang,Kim
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- Use of ozone for preparing 4-nitrobenzoic acid in a closed process cycle
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The possibility of preparing 4-nitrobenzoic acid in a closed process cycle by oxidation of 4-nitrotoluene with an ozone air mixture was examined. The optimal conditions of oxidation with multiple use of mother liquors were found, and the conditions for crystallization of 4-nitrobenzoic acid from the reaction mixture were determined. The effects of water, acetic anhydride, and catalyst on the oxidation performed in mother liquors after filtration of the target product were examined.
- Galstyan,Tyupalo,Patapenko,Andreev
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- Transformation of Thioacids into Carboxylic Acids via a Visible-Light-Promoted Atomic Substitution Process
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A visible-light-promoted atomic substitution reaction for transforming thiocacids into carboxylic acids with dimethyl sulfoxide (DMSO) as the oxygen source has been developed, affording various alkyl and aryl carboxylic acids in over 90% yields. The atomic substitution process proceeds smoothly through the photochemical reactivity of the formed hydrogen-bonding adduct between thioacids and DMSO. A DMSO-involved proton-coupled electron transfer (PCET) and the simultaneous generation of thiyl and hydroxyl radicals are proposed to be key steps for realizing the transformation.
- Fu, Qiang,Liang, Fu-Shun,Lou, Da-Wei,Pan, Gao-Feng,Wang, Rui,Wu, Min,Xie, Kai-Jun
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supporting information
p. 2020 - 2024
(2022/03/31)
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- Disproportionation of aliphatic and aromatic aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions
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Disproportionation of aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions often requires the application of high temperatures, equimolar or excess quantities of strong bases, and is mostly limited to the aldehydes with no CH2 or CH3 adjacent to the carbonyl group. Herein, we developed an efficient, mild, and multifunctional catalytic system consisting AlCl3/Et3N in CH2Cl2, that can selectively convert a wide range of not only aliphatic, but also aromatic aldehydes to the corresponding alcohols, acids, and dimerized esters at room temperature, and in high yields, without formation of the side products that are generally observed. We have also shown that higher AlCl3 content favors the reaction towards Cannizzaro reaction, yet lower content favors Tishchenko reaction. Moreover, the presence of hydride donor alcohols in the reaction mixture completely directs the reaction towards the Meerwein–Ponndorf–Verley reaction. Graphic abstract: [Figure not available: see fulltext.].
- Sharifi, Sina,Sharifi, Hannah,Koza, Darrell,Aminkhani, Ali
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p. 803 - 808
(2021/07/20)
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- Reactivity of secondary N-alkyl acrylamides in Morita–Baylis–Hillman reactions
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The Morita–Baylis–Hillman (MBH) reaction of secondary N-alkyl acrylamides, discarded up to now from investigations of the scope of activated alkenes, was studied. Optimization of the reaction conditions revealed that a balance must be found between activation of the MBH coupling reaction and that of the undesired competitive aldehyde Cannizzaro reaction. Using 3-Hydroxyquinuclidine (3-HQD) in a 1:1 water-2-MeTHF mixture provides the appropriate conditions that were applicable to a wide range of diversely substituted secondary N-alkyl acrylamides and aromatic aldehydes, giving rise to novel amide-containing MBH adducts under mild and clean conditions.
- Ahmar, Mohammed,Queneau, Yves,Verrier, Charlie,Yue, Xiaoyang
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p. 319 - 330
(2021/10/29)
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- Practical scale up synthesis of carboxylic acids and their bioisosteres 5-substituted-1H-tetrazoles catalyzed by a graphene oxide-based solid acid carbocatalyst
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Herein, catalytic application of a metal-free sulfonic acid functionalized reduced graphene oxide (SA-rGO) material is reported for the synthesis of both carboxylic acids and their bioisosteres, 5-substituted-1H-tetrazoles. SA-rGO as a catalytic material incorporates the intriguing properties of graphene oxide material with additional benefits of highly acidic sites due to sulfonic acid groups. The oxidation of aldehydes to carboxylic acids could be efficiently achieved using H2O2as a green oxidant with high TOF values (9.06-9.89 h?1). The 5-substituted-1H-tetrazoles could also be effectively synthesized with high TOF values (12.08-16.96 h?1). The synthesis of 5-substituted-1H-tetrazoles was corroborated by single crystal X-ray analysis and computational calculations of the proposed reaction mechanism which correlated well with experimental findings. Both of the reactions could be performed efficiently at gram scale (10 g) using the SA-rGO catalyst. SA-rGO displays eminent reusability up to eight runs without significant decrease in its productivity. Thus, these features make SA-rGO riveting from an industrial perspective.
- Mittal, Rupali,Kumar, Amit,Awasthi, Satish Kumar
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p. 11166 - 11176
(2021/03/31)
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- Ni-NiO heterojunctions: a versatile nanocatalyst for regioselective halogenation and oxidative esterification of aromatics
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Herein, we report a facile method for the synthesis of Ni-NiO heterojunction nanoparticles, which we utilized for the nuclear halogenation reaction of phenol and substituted phenols usingN-bromosuccinimide (NBS). A remarkablepara-selectivity was achieved for the halogenated products under semi-aqueous conditions. Interestingly, blocking of thepara-position of phenol offeredortho-selective halogenation. In addition, the Ni-NiO nanoparticles catalyzed the oxidative esterification of carbonyl compounds with alcohol, diol or dithiol in the presence of a catalytic amount of NBS. It was observed that the aromatic carbonyls substituted with an electron-donating group favoured nuclear halogenation, whereas an electron-withdrawing group substitution in carbonyl compounds facilitated the oxidation reaction. In addition, the catalyst was magnetically separated and recycled 10 times. The tuned electronic structure at the Ni-NiO heterojunction controlled selectivity and activity as no suchpara-selectivity was observed with commercially available NiO or Ni nanoparticles.
- Bhardwaj, Nivedita,Goel, Bharat,Indra, Arindam,Jain, Shreyans K.,Singh, Ajit Kumar,Tripathi, Nancy
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p. 14177 - 14183
(2021/08/16)
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- MOF-Zn-NHC as an efficient N-heterocyclic carbene catalyst for aerobic oxidation of aldehydes to their corresponding carboxylic acids: Via a cooperative geminal anomeric based oxidation
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As an efficient heterogenous N-heterocyclic carbene (NHC) catalyst, MOF-Zn-NHC was used in the aerobic oxidation of aryl aldehydes to their corresponding carbocyclic acids via an anomeric based oxidation. Features such as mild reaction conditions and no need for a co-catalyst or oxidative reagent can be considered as the major advantages of the presented method in this study. This journal is
- Babaee, Saeed,Zarei, Mahmoud,Zolfigol, Mohammad Ali
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p. 36230 - 36236
(2021/12/02)
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- Aerobic oxidation of aldehydes to carboxylic acids catalyzed by recyclable ag/c3 n4 catalyst
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The oxidation of aldehydes is an efficient methodology for the synthesis of carboxylic acids. Herein we hope to report a simple, efficient and recyclable protocol for aerobic oxidation of aldehydes to carboxylic acid by using C3N4 supported silver nanoparticles (Ag/C3N4) as a catalyst in aqueous solution under mild conditions. Under standard conditions, the corresponding carboxylic acids can be obtained in good to excellent yields. In addition, Ag/C3N4 is convenient for recovery and could be reused three times with satisfactory yields.
- Wu, Chaolong,Yao, Xiaoquan,Yu, Min,Zhou, Li,Zhu, Li
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p. 167 - 175
(2021/03/19)
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- Continuous production method of benzoic acid derivative
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The invention relates to the technical field of preparation of benzoic acid derivatives. The invention particularly relates to a continuous production method of a benzoic acid derivative. The continuous reaction device is characterized by comprising a small-diameter sleeve, wherein the small-diameter sleeve is sleeved with a large-diameter sleeve, and a small pipeline is arranged between the small-diameter sleeve and the large-diameter sleeve, and a plurality of small holes are arranged on the small pipeline. The small-diameter casing is rotated, the large-diameter casing is fixed, and the reaction liquid composed of the nitric acid and the toluene derivative is between a small-diameter casing pipe and a large-diameter casing pipe.
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Paragraph 0027; 0030-0031
(2021/11/14)
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- An efficient chromium(iii)-catalyzed aerobic oxidation of methylarenes in water for the green preparation of corresponding acids
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A highly efficient method to oxidize methylarenes to their corresponding acids with a reusable Cr catalyst was developed. The reaction can be carried out in water with 1 atm oxygen and K2S2O8as cooxidants, proceeds under green and mild conditions, and is suitable for the oxidation of both electron-deficient and electron-rich methylarenes, including heteroaryl methylarenes, even at the gram level. The excellent result, together with its simplicity of operation and the ability to continuously reuse the catalyst, makes this new methodology environmentally benign and cost-effective. The generality of this methodology gives it the potential for use on an industrial scale. Differing from the accepted oxidation mechanism of toluene, GC-MS studies and DFT calculations have revealed that the key benzyl alcohol intermediate is formed under the synergetic effect of the chromium and molybdenum in the Cr catalyst, which can be further oxidized to afford benzaldehyde and finally benzoic acid.
- Jiang, Feng,Liu, Shanshan,Wei, Yongge,Yan, Likai,Yu, Han,Zhao, Wenshu
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supporting information
p. 12413 - 12418
(2021/09/28)
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- Photo-induced deep aerobic oxidation of alkyl aromatics
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Oxidation is a major chemical process to produce oxygenated chemicals in both nature and the chemical industry. Presently, the industrial manufacture of benzoic acids and benzene polycarboxylic acids (BPCAs) is mainly based on the deep oxidation of polyalkyl benzene, which is somewhat suffering from environmental and economical disadvantage due to the formation of ozone-depleting MeBr and corrosion hazards of production equipment. In this report, photo-induced deep aerobic oxidation of (poly)alkyl benzene to benzene (poly)carboxylic acids was developed. CeCl3 was proved to be an efficient HAT (hydrogen atom transfer) catalyst in the presence of alcohol as both hydrogen and electron shuttle. Dioxygen (O2) was found as a sole terminal oxidant. In most cases, pure products were easily isolated by simple filtration, implying large-scale implementation advantages. The reaction provides an ideal protocol to produce valuable fine chemicals from naturally abundant petroleum feedstocks. [Figure not available: see fulltext.].
- Wang, Chang-Cheng,Zhang, Guo-Xiang,Zuo, Zhi-Wei,Zeng, Rong,Zhai, Dan-Dan,Liu, Feng,Shi, Zhang-Jie
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p. 1487 - 1492
(2021/07/10)
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- Bimetallic oxide nanoparticles confined in ZIF-67-derived carbon for highly selective oxidation of saturated C–H bond in alkyl arenes
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Zeolite imidazolate frameworks (ZIFs) have recently emerged as an ideal type of carbon precursors with abundant tailorability. In this work, a series of ZIF-derived porous carbon catalysts have been prepared with encapsulation of bimetallic oxide nanoparticles via simple thermal treatment. The composition and structure of these catalysts were confirmed in detail by different characterization methods. The bimetallic oxide (Mn/Co, Fe/Co, and Cu/Co) nanoparticles were encapsulated in the nitrogen-doped graphitized carbon matrix. Moreover, the hierarchically porous structure and carbon defects were successfully constructed in the carbon catalysts. Additionally, in the selective oxidation of saturated C–H bonds in alkyl arenes, the carbon catalysts demonstrate outstanding performance for the oxidation of C–H bonds to corresponding carboxyl groups. This was due to their unique structure can greatly promote mass transfer and molecular oxygen activation, resulting in high conversion and high selectivity. Remarkably, this work here could also provide a novel strategy to the controllable synthesis of metal–organic frameworks (MOFs)-derived carbon catalysts for enhanced performance in heterogeneous catalysis.
- Huang, Cheng,Su, Xiaoyan,Gu, Xiangyu,Liu, Rui,Zhu, Hongjun
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- Rapid gram-scale synthesis of Au/chitosan nanoparticles catalysts using solid mortar grinding
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Owing to the abundant functional groups present in the chitosan polymer, high density catalytic tiny gold particles with greater dispersion can be anchored on the chitosan powder using simple mortar and pestle. Chitosan-supported gold nanoparticles (NPs) with excellent control of size and shape were rapidly synthesized in gram-scale by solid-grinding without the need of any toxic solvents. The structure of catalysts and products was established by advanced instrumental and spectroscopic methods. The supported gold NPs functions as a heterogeneous catalyst for the homocoupling of phenylboronic acid and the aerobic oxidation of benzyl alcohol in water. The catalytic behaviour and activity of supported gold NPs was tuned/modulated by varying the ratio of chitosan polymer and gold precursor. Comparative studies showed that the solid chitosan supported gold catalyst exhibits superior catalytic activity and selectivity than the well known hydrophilic polymer-stabilized gold NPs catalysts prepared by the conventional solution-based methods.
- Reddy, K. Paul,Meerakrishna,Shanmugam,Satpati, Biswarup,Murugadoss
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p. 438 - 446
(2021/01/11)
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- Cu(II)-Based Ionic Liquid Supported on SBA-15 Nanoparticles Catalyst for the Oxidation of Various Alcohols into Carboxylic Acids in the Presence of CO2
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In this paper, we have produced carboxylic acids by the oxidation of various alcohols in the presence of CO2 using SBA-15/IL supported Cu(II) (SBA-15/IL/Cu(II)) as nanocatalyst. The obtained products showed to have excellent yields by taking into account of SBA-15/IL/Cu(II) nanocatalyst. In addition, the analysis of EDX, SEM, TGA, TEM, XPS, and FT-IR showed the heterogeneous structure of SBA-15/IL/Cu (II) catalyst. It is determined that, after using SBA-15 excess, the catalytic stability of the system was enhanced. Moreover, hot filtration provided a full vision in the heterogeneous catalyst nature. The recycling as well as reuse of the catalyst were studied in cases of coupling reactions many times. Moreover, we have studied the mechanism of the coupling reactions. Graphic Abstract: [Figure not available: see fulltext.]
- Chen, Yanwu,Hou, Dejian,Lin, Litian,Peng, Qi,Sadeghzadeh, Seyed Mohsen
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- Combining photoredox catalysis and oxoammonium cations for the oxidation of aromatic alcohols to carboxylic acids
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A methodology is reported for converting alcohols to the corresponding carboxylic acids. A dual catalytic system involving a merger of photoredox catalysis and 4-acetamido-TEMPO is employed to carry out this oxidation process.
- Nandi, Jyoti,Hutcheson, Ellen L.,Leadbeater, Nicholas E.
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supporting information
(2020/12/25)
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- Oxidation of Primary Alcohols and Aldehydes to Carboxylic Acids via Hydrogen Atom Transfer
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The oxidation of primary alcohols and aldehydes to the corresponding carboxylic acids is a fundamental reaction in organic synthesis. In this paper, we report a new chemoselective process for the oxidation of primary alcohols and aldehydes. This metal-free reaction features a new oxidant, an easy to handle procedure, high isolated yields, and good to excellent functional group tolerance even in the presence of vulnerable secondary alcohols and tert-butanesulfinamides.
- Tan, Wen-Yun,Lu, Yi,Zhao, Jing-Feng,Chen, Wen,Zhang, Hongbin
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supporting information
p. 6648 - 6653
(2021/09/08)
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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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- Green synthesis of a vanadium(V) Schiff base complex by grinding method: study on its catalytic and anti-bacterial activity
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A facile protocol was developed for the green synthesis of a Schiff base and its vanadium(V) complex. The compounds were derived from salicylaldehyde, diethylenetriamine and vanadyl sulfate by applying grinding method to overcome environmental issues with solvents. The reactions took place rapidly and products were isolated pure. The compounds were characterized with elemental, EDX, mass spectrometry, magnetic susceptibility, molar conductance, UV-vis, FTIR and NMR analysis. The synthesized vanadium(V) complex was an efficient and selective catalyst towards oxidation of organic sulfides and alcohols. The oxidation reactions were conducted under microwave irradiation as well as conventional heating. A reaction mechanism has been proposed for the catalytic oxidation reactions. The mechanism was further established by using GAUSSIAN16 suite. The complex also showed good anti-bacterial activity against Gram-positive and Gram-negative bacteria.
- Boruah, Jeena Jyoti,Bhatt, Zankhana S.,Nathani, Chirag R.,Bambhaniya, Vaishali J.,Guha, Ankur Kanti,Das, Siva Prased
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p. 2055 - 2068
(2021/06/27)
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- Hydrolysis of amides to carboxylic acids catalyzed by Nb2O5
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Hydrolysis of amides to carboxylic acids is an industrially important reaction but is challenging due to the difficulty of cleaving the resonance stabilized amidic C-N bond. Twenty-three heterogeneous and homogenous catalysts were examined in the hydrolysis of acetamide. Results showed that Nb2O5was the most effective heterogeneous catalyst with the greatest yield of acetic acid. A series of Nb2O5catalysts calcined at various temperatures were characterized and tested in the hydrolysis of acetamide to determine the effects of crystal phase and surface properties of Nb2O5on catalytic performance. The high catalytic performance observed was attributed mainly to the facile activation of the carbonyl bond by Lewis acid sites that function even in the presence of basic inhibitors (NH3and H2O). The catalytic studies showed the synthetic advantages of the present method, such as simple operation, catalyst recyclability, additive free, solvent free, and wide substrate scope (>40 examples; up to 95% isolated yield).
- Siddiki,Rashed, Md. Nurnobi,Touchy, Abeda Sultana,Jamil, Md. A. R.,Jing, Yuan,Toyao, Takashi,Maeno, Zen,Shimizu, Ken-Ichi
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p. 1949 - 1960
(2021/03/26)
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- Nitration of deactivated aromatic compounds via mechanochemical reaction
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A variety of deactivated arenes were nitrated to their corresponding nitro derivatives in excellent yields under high-speed ball milling condition using Fe(NO3)3·9H2O/P2O5 as nitrating reagent. A radical involved mechanism was proposed for this facial, eco-friendly, safe, and effective nitration reaction.
- Wu, Jian-Wei,Zhang, Pu,Guo, Zhi-Xin
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supporting information
(2021/05/05)
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- Acetyl nitrate mediated conversion of methyl ketones to diverse carboxylic acid derivatives
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The development of a novel acetyl nitrate mediated oxidative conversion of methyl ketones to carboxylic acid derivatives is described. By analogy to the haloform reaction and supported by experimental and computational investigation we propose a mechanism for this transformation.
- Bernard, Josephine,Capilato, Joseph N.,Hoy, Erik P.,Mattiucci, Joseph,Pellegrinelli, Peter J.,Perez, Lark J.,Philippi, Shane,Schnorbus, Logan
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p. 5298 - 5302
(2021/06/30)
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- Efficiency of lithium cations in hydrolysis reactions of esters in aqueous tetrahydrofuran
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Lithium cations were observed to accelerate the hydrolysis of esters with hydroxides (KOH, NaOH, LiOH) in a water/tetrahydrofuran (THF) two-phase system. Yields in the hydrolysis of substituted benzoates and aliphatic esters using the various hydroxides were compared, and the effects of the addition of lithium salt were examined. Moreover, it was presumed that a certain amount of LiOH was dissolved in THF by the coordination of THF with lithium cation and hydrolyzed esters even in the THF layer, as in the reaction by a phase-transfer catalyst.
- Harada, Yumi,Hayashi, Kazuhiko,Ichimaru, Yoshimi,Imai, Masanori,Kojima, Yuki,Maeda, Azusa,Nakayama, Kanae,Sugiura, Kirara
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p. 581 - 594
(2021/06/06)
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- Light-induced carboxylation of aryl derivatives with cooperative COF as an active photocatalyst and Ni(ii) co-catalyst
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The photocatalytic carboxylation of aryl derivatives was demonstrated under CO2at atmospheric pressure using a mesoporous covalent organic framework (COF) as the active photocatalyst with triethylamine (TEA) as a sacrificial electron source under visible light. A yield of greater than 91% of the isolated product was achieved with 5 mg of catalyst. The reaction cycle is dependent on the use of the Ni(dmg)2co-catalyst and the sacrificial electron donor (TEA). The reaction does not occur in the absence of light (445 nm) even at elevated reaction temperature. We have also demonstrated that a yield of 32% of the isolated product could be obtained with the use of sunlight in the catalytic cycle. Additionally, this heterogeneous catalytic system was recyclable and reusable for several cycles.
- Chakrabortty, Pekham,Das, Anjan,Chowdhury, Arpita Hazra,Ghosh, Swarbhanu,Khan, Aslam,Islam, Sk. Manirul
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p. 4738 - 4745
(2021/03/22)
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- Ipso Nitration of Aryl Boronic Acids Using Fuming Nitric Acid
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The ipso nitration of aryl boronic acid derivatives has been developed using fuming nitric acid as the nitrating agent. This facile procedure provides efficient and chemoselective access to a variety of aromatic nitro compounds. While several activating agents and nitro sources have been reported in the literature for this synthetically useful transformation, this report demonstrates that these processes likely generate a common active reagent, anhydrous HNO3. Kinetic and mechanistic studies have revealed that the reaction order in HNO3 is >2 and indicate that the ?NO2 radical is the active species.
- Baucom, Kyle D.,Brown, Derek B.,Caille, Seb,Murray, James I.,Quasdorf, Kyle,Silva Elipe, Maria V.
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supporting information
(2021/06/30)
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- Cobalt-Catalyzed Deprotection of Allyl Carboxylic Esters Induced by Hydrogen Atom Transfer
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A brief, efficient method has been developed for the removal of the allyl protecting group from allyl carboxylic esters using a Co(II)/TBHP/(Me2SiH)2O catalytic system. This facile strategy displays excellent chemoselectivity, functional group tolerance, and high yields. This transformation probably occurs through the hydrogen atom transfer process, and a Co(III)-six-membered cyclic intermediate is recommended.
- Li, Nan,Gui, Yizhen,Chu, Mengqi,You, Mengdi,Qiu, Xiaohan,Liu, Hejia,Wang, Shiang,Deng, Meng,Ji, Baoming
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supporting information
p. 8460 - 8464
(2021/11/13)
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- Fluorine-containing aromatic diamine compound and preparation method thereof, and fluorine-containing polyimide compound and preparation method thereof
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The invention provides a fluorine-containing aromatic diamine compound and a preparation method thereof, and a fluorine-containing polyimide compound and a preparation method thereof. The fluorine-containing aromatic diamine compound has a structural general formula shown in the specification. The preparation method of the fluorine-containing aromatic diamine compound comprises the following stepsof: mixing materials including a compound A and a compound B, carrying out a first reaction to obtain a compound C, and carrying out a hydrogenation reaction on the compound C to obtain the fluorine-containing aromatic diamine compound. Raw materials of the fluorine-containing polyimide compound comprise the fluorine-containing aromatic diamine compound. The preparation method of the fluorine-containing polyimide compound comprises the following steps of: mixing materials including the fluorine-containing aromatic diamine compound and a dianhydride compound to obtain a mixture, and then carrying out a sixth reaction to obtain a precursor; and carrying out dehydration cyclization reaction on the pre-polymer, and carrying out post-treatment to obtain the fluorine-containing polyimide compound. The polyimide compound prepared from the fluorine-containing aromatic diamine compound provided by the invention is good in solubility, relatively high in transmittance and good in mechanical property.
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Paragraph 0129; 0134-0137
(2021/01/29)
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- Antiaggregant effects of (1,2,5-oxadiazolyl)azasydnone ring assemblies as novel antiplatelet agents
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A series of biheterocyclic assemblies comprising of 1,2,5-oxadiazole and azasydnone scaffolds were synthesized and biologically evaluated as novel nitric oxide (NO)-donor and antiplatelet agents. Depending on functional substituents at the biheterocyclic core, all studied compounds demonstrated good NO-donor profiles releasing NO in a wide range of concentrations (19.2%–195.1%) according to a Griess assay. (1,2,5-Oxadiazolyl)azasydnones showed excellent antiplatelet activity in the case of ADP and adrenaline used as inducers completely suppressing the aggregate formation even at the lowest test concentration of 0.0375?μmol/ml, which is a rather unique feature. Moreover, studied biheterocycles possess a selective mechanism of inhibition of platelet aggregation mediated only by ADP and adrenaline, which are considered to be the main inducers causing thrombus formation. In addition, (1,2,5-oxadiazolyl)azasydnones were found to be completely non-toxic to hybrid endothelial cells EaHy 926. Studies of hydrolytic degradation of the synthesized compounds afforded benzoic acid as a sole detectable decomposition product, which is considered advantageous in drug design. Therefore, (1,2,5-oxadiazolyl)azasydnones represent a novel class of promising drug candidates with improved antiplatelet profile and reduced toxicity enabling their huge potential in medicinal chemistry and drug design.
- Fershtat, Leonid L.,Makhova, Nina N.,Nifantiev, Nikolay E.,Ustyuzhanina, Nadezhda E.,Zhilin, Egor S.
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- Catalytic production of anilines by nitro-compounds hydrogenation over highly recyclable platinum nanoparticles supported on halloysite nanotubes
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Pt-nanoparticles supported on halloysite-nanotubes (HNTs) were selectively deposited onto the inner (Pt(IN)/HNT) or outer (Pt(OUT)/HNT) surface of the support to evaluate their operational stability on the cleaner and efficient hydrogenation of nitro compounds to produce their corresponding anilines. The formation of Pt0-aggregates on the inner or outer surfaces was observed, with mean particles sizes of 2.4–2.9 nm. The catalysts were evaluated using ethanol as solvent and nitrobenzene as a model substrate at a temperature of 298 K, under 1 bar of H2 pressure. The Pt(IN)/HNT catalyst showed better catalytic performance than Pt(OUT)/HNT, which was mainly attributed to the confinement effect of the Pt-nanoparticles inside the HNTs. However, the operational stability showed that Pt(OUT)/HNT retained its catalytic performance after 15 cycles, while the Pt(IN)/HNT catalyst suffered deactivation after the 5th cycle. The best catalytic system showed a moderate-to-high efficiency in the efficient hydrogenation of 7 nitro compounds used to produce their corresponding anilines, which are important pharmaceutical building blocks.
- Aepuru, Radhamanohar,Bustamante, Tatiana M.,Campos, Cristian H.,Leal-Villarroel, Edgardo,Mangalaraja, Ramalinga Viswanathan,Shanmugaraj, Krishnamoorthy,Torres, Cecilia C.,Vinoth, Victor
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- Alkali-modified heterogeneous Pd-catalyzed synthesis of acids, amides and esters from aryl halides using formic acid as the CO precursor
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To establish an environmentally friendly green chemical process, we minimized and resolved a significant proportion of waste and hazards associated with conventional organic acids and molecular gases, such as carbon monoxide (CO). Herein, we report a facile and milder reaction procedure, using low temperatures/pressures and shorter reaction time for the carboxyl- and carbonylation of diverse arrays of aryl halides over a newly developed cationic Lewis-acid promoted Pd/Co3O4catalyst. Furthermore, the reaction proceeded in the absence of acid co-catalysts, and anhydrides for CO release. Catalyst reusability was achievedviascalable, safer, and practical reactions that provided moderate to high yields, paving the way for developing a novel environmentally benign method for synthesizing carboxylic acids, amides, and esters.
- Fapojuwo, Dele Peter,Maqunga, Nomathamsanqa Prudence,Meijboom, Reinout,Mogudi, Batsile M.,Molokoane, Pule Petrus,Onisuru, Oluwatayo Racheal,Oseghale, Charles O.
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p. 26937 - 26948
(2021/08/17)
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- Pd(II) porphyrins: Synthesis, singlet oxygen generation and photoassisted oxidation of aldehydes to carboxilic acids
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The synthesis and spectral studies of A3B and A2B2 type porphyrins and their Pd(II) complexes are reported. The meso-positions on porphyrin macrocycle are substituted with pentafluorophenyl and N-butylcarbazole or triphenylamine groups. Pd(II) porphyrins displayed decent phosphorescence ～670 nm and are able to produce singlet oxygen by type II pathway, after photoirradiation. The calculated singlet oxygen quantum yields for Pd(II) porphyrins are (ΦΔ = 30%–63%). The catalytic application of Pd(II) porphyrins towards photoassisted aerobic oxidation of aromatic aldehydes to carboxylic acids is demonstrated.
- Pandey, Vijayalakshmi,Jain, Drishti,Pareek, Nitesh,Gupta, Iti
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- Photoinduced Carbon Tetrabromide Initiated Aerobic Oxidation of Substituted Toluenes to Carboxylic Acids
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A mild and metal-free procedure is reported for the aerobic oxidation of substituted toluenes to carboxylic acids by using CBr 4 as initiator under irradiation from a 400 nm blue light-emitting diode.
- Li, Xiaoqing,Xu, Xiangsheng,Yan, Xiaoyu,Yan, Xinhuan,Zhang, Guofu,Zheng, Kun
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p. 272 - 274
(2020/02/18)
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- Catalytic C-H aerobic and oxidant-induced oxidation of alkylbenzenes (including toluene derivatives) over VO2+immobilized on core-shell Fe3O4?SiO2at room temperature in water
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Direct C-H bond oxidation of organic materials, and producing the necessary oxygenated compounds under mild conditions, has attracted increasing interest. The selective oxidation of various alkylbenzenes was carried out by means of a new catalyst containing VO2+ species supported on silica-coated Fe3O4 nanoparticles using t-butyl hydroperoxide as an oxidant at room temperature in H2O or solvent-free media. The chemical and structural characterization of the catalyst using several methods such as FTIR spectroscopy, XRD, FETEM, FESEM, SAED, EDX and XPS showed that VO2+ is covalently bonded to the silica surface. High selectivity and excellent conversion of various toluene derivatives, with less reactive aliphatic (sp3) C-H bonds, to related benzoic acids were quite noticeable. The aerobic oxygenation reaction of these alkylbenzenes was studied under the same conditions. All the results accompanied by sustainability of the inexpensive and simple magnetically separable heterogeneous catalyst proved the important criteria for commercial applications. This journal is
- Mohammadpour, Pegah,Safaei, Elham
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p. 23543 - 23553
(2020/07/14)
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- N-Hydroxy-1,6-methano[10]annulene-3,4-dicarboximide/Co(OAc)2: A novel catalytic system for the aerobic oxidation of alkylarenes
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Alkylbenzenes were aerobically oxidized to their oxygenated products via a novel catalytic system using N-hydroxy-1,6-methano[10]annulene-3,4-dicarboximide (2) and cobalt(II) acetate under mild conditions. A radical mechanism has been proposed to account for the aerobic oxidation of these hydrocarbons. The 2/Co(OAc)2 catalytic system was optimized and the reaction scope was explored.
- Zuo, Shengli,Liu, Jianjun,Zuo, Ang
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p. 2634 - 2639
(2020/04/15)
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- 9,10-Dihydroanthracene auto-photooxidation efficiently triggered photo-catalytic oxidation of organic compounds by molecular oxygen under visible light
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The development of mild and efficient process for the selective oxidation of organic compounds by molecular oxygen (O2) can be one of the key technologies for synthesizing oxygenates. This paper discloses an efficient and mild synthesis protocol for the O2-involved ethylbenzene (EB) photooxidation triggered by 910-dihydroanthracene (DHA) auto- photooxidation in acetone under visible light illumination, which can achieve 87.7 percent EB conversion and 99.5 percent acetylacetone (ACP) selectivity under ambient conditions. Also, 62.9 percent EB conversion and 96.3 percent ACP selectivity is obtained in air atmosphere. Furthermore, this protocol has a good adaptability for the photooxidation of other organic substrates such as tetrahydronaphthalene, diphenylmethane, toluene, cyclohexane, cyclohexene, alcohol, methylfuran and thioether to their corresponding oxygenates. A series of control and quenching tests, combined with EPR spectra, suggest that the photo-excited DHA can transfer its photo-electron to O2 to yield a superoxide radical anion (O2??), then DHA is preferentially oxidized to anthraquinone (AQ) by the active O2?? owing to its high reactivity. Finally, the in situ generated AQ as an active photo-catalyst can achieve the photooxidation of EB and other organic compounds by O2. The present photo-autoxidation protocol gives a good example for the O2-based selective oxidation of inert hydrocarbons under mild conditions.
- Chen, Mengke,Deng, Youer,Fu, Zaihui,Hu, Wenwei,Jiang, Dabo,Liu, Yachun,Mao, Feng,Su, Anqun,Yang, Bo,Zhang, Chao
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- A tunable synthesis of either benzaldehyde or benzoic acid through blue-violet LED irradiation using TBATB
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In this paper, a highly efficient, metal-free, and homogeneous method for the selective aerobic photooxidation of alcohols and photooxidative-desilylation of tert-butyldimethylsilyl ethers (TBDMS) in the presence of tetrabutylammonium tribromide (TBATB) under irradiation of visible light was reported. The light source: blue (460 nm) and violet (400 nm) LED, can control selective oxidation to aldehyde or carboxylic acid.
- Mardani, Atefeh,Heshami, Marouf,Shariati, Yadollah,Kazemi, Foad,Abdollahi Kakroudi, Mazaher,Kaboudin, Babak
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- Palladium supported on a novel ordered mesoporous polypyrrole/carbon nanocomposite as a powerful heterogeneous catalyst for the aerobic oxidation of alcohols to carboxylic acids and ketones on water
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Preparation of an ordered mesoporous polypyrrole/carbon (PPy/OMC) composite has been described through a two-step nanocasting process using KIT-6 as a template. Characterization of the PPy/OMC nanocomposite by various analysis methods such as TEM, XRD, TGA, SEM and N2 sorption confirmed the preparation of a material with ordered mesoporous structure, uniform pore size distribution, high surface area and high stability. This nanocomposite was then used for the immobilization of palladium nanoparticles. The nanoparticles were almost uniformly distributed on the support with a narrow particle size of 20-25 nm, confirmed by various analysis methods. Performance of the Pd?PPy/OMC catalyst was evaluated in the aerobic oxidation of various primary and secondary alcohols on water as a green solvent, giving the corresponding carboxylic acids and ketones in high yields and excellent selectivity. The catalyst could also be reused for at least 10 reaction runs without losing its catalytic activity and selectivity. High catalytic efficiency of the catalyst can be attributed to a strong synergism between the PPy/OMC and that of supported Pd nanoparticles.
- Ganji, Nasim,Karimi, Babak,Najafvand-Derikvandi, Sepideh,Vali, Hojatollah
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p. 13616 - 13631
(2020/04/24)
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- A sodium trifluoromethanesulfinate-mediated photocatalytic strategy for aerobic oxidation of alcohols
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A sodium trifluoromethanesulfinate-mediated photocatalytic strategy for the aerobic oxidation of alcohols has been developed for the first time, and the photoredox aerobic oxidation of secondary and primary alcohols provided the corresponding ketones and carboxylic acids, respectively, in high to excellent yields.
- Zhu, Xianjin,Liu, Can,Liu, Yong,Yang, Haijun,Fu, Hua
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p. 12443 - 12446
(2020/10/30)
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- Highly efficient oxidation of alcohols to carboxylic acids using a polyoxometalate-supported chromium(iii) catalyst and CO2
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Direct catalytic oxidation of alcohols to carboxylic acids is very attractive, but economical catalysis systems have not yet been well established. Here, we show that a pure inorganic ligand-supported chromium compound, (NH4)3[CrMo6O18(OH)6] (simplified as CrMo6), could be used to effectively promote this type of reaction in the presence of CO2. In almost all cases, oxidation of various alcohols (aromatic and aliphatic) could be achieved under mild conditions, and the corresponding carboxylic acids can be achieved in high yield. The chromium catalyst 1 can be reused several times with little loss of activity. Mechanism study and control reactions demonstrate that the acidification proceeds via the key oxidative immediate of aldehydes.
- Han, Sheng,Wang, Ying,Wei, Yongge,Wu, Zhikang,Yu, Han
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p. 3150 - 3154
(2020/06/19)
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- Metal-Organic Framework Based on Heptanuclear Cu-O Clusters and Its Application as a Recyclable Photocatalyst for Stepwise Selective Catalysis
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Visible-light driven photoreactions using metal-organic frameworks (MOFs) as catalysts are promising with regard to their environmental friendly features such as the use of renewable and sustainable energy of visible light and potential catalyst recyclability. To develop potential heterogeneous photocatalysts, a family of three copper(II) coordination polymers bearing different Cu-O assemblies have been synthesized with the ligand 4,4-disulfo-[1,1-biphenyl]-2,2-dicarboxylate acid (H4DSDC), namely, {[Cu7(DSDC)2(OH)6(H2O)10]·xH2O}n (1), {[Cu4(DSDC)(4,4-bpy)2(OH)4]·2H2O}n (2), and {Cu2(DSDC)(phen)2(H2O)2}n (3) (4,4-bpy = 4,4-bipyridine and phen = 1,10-phenanthroline). Complex 1 represents a metal-organic framework featuring a NbO type topology constructed from the infinite linkage of heptanuclear [Cu7(μ3-OH)6(H2O)10]8+ clusters by deprotonated DSDC4- ligands, comprising one-dimensional hexagonal channels of a diameter around 11 ? that are filled with water molecules. The infinite waving {[Cu2(OH)2]2+}n ladderlike chains in complex 2 are bridged by DSDC4- and 4,4-bpy ligands into a three-dimensional framework. A two-dimensional layered structure is formed in complex 3 due to the existence of terminal phenanthroline ligands. All of the coordination polymers 1-3 are able to catalyze the visible-light driven oxidation of alcohols at mild conditions using hydrogen peroxide as an oxidant, in which complex 1 demonstrates satisfactory efficiency. Significantly for this photoreaction catalyzed by 1, the extent of oxidation over aryl primary alcohols is fully controllable with time-resolved product selectivity, giving either corresponding aldehydes or carboxylate acids in good yields. It is also remarkable that the photocatalyst could be recovered almost quantitatively on completion of the catalytic cycle without any structure change, and could be recycled for catalytic use for at least five cycles with constant efficiency. This photocatalyst with time-resolved selectivity for different products may provide new insight into the design and development of novel catalytic systems.
- Zhou, Jie,Huang-Fu, Xu,Huang, Yang-Ying,Cao, Chu-Ning,Han, Jie,Zhao, Xiao-Li,Chen, Xu-Dong
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p. 254 - 263
(2019/12/04)
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- Copper (II) immobilized on magnetically separable L-arginine-β-cyclodextrin ligand system as a robust and green catalyst for direct oxidation of primary alcohols and benzyl halides to acids in neat conditions
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Copper (II) immobilized on L-arginine-β-cyclodextrin-functionalized magnetite nanoparticles (nano-Fe3O4@L-arginine-CD-Cu(II)) were successfully synthesized and fully characterized using FT-IR, XRD, SEM, EDX, ICP, TGA and VSM techniques. The catalytic activity of these magnetically retrievable nanoparticles was evaluated in the direct oxidation of primary alcohols and benzyl halides to acids in neat conditions that was observed to proceed well and products were obtained in good yields. In addition to showing good catalytic activity, the magnetic catalyst is easy to synthesize and can be recycled at least five times with little loss in activity.
- Nejad, Masoumeh Jadidi,Salamatmanesh, Arefe,Heydari, Akbar
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- Cobalt-Catalyzed Acceptorless Dehydrogenation of Alcohols to Carboxylate Salts and Hydrogen
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The facile oxidation of alcohols to carboxylate salts and H2 is achieved using a simple and readily accessible cobalt pincer catalyst (NNNHtBuCoBr2). The reaction follows an acceptorless dehydrogenation pathway and displays good functional group tolerance. The amine-amide metal-ligand cooperation in cobalt catalyst is suggested to facilitate this transformation. The mechanistic studies indicate that in-situ-formed aldehydes react with a base through a Cannizzaro-type pathway, resulting in potassium hemiacetolate, which further undergoes catalytic dehydrogenation to provide the carboxylate salts and H2
- Gunanathan, Chidambaram,Kishore, Jugal,Pattanaik, Sandip,Pradhan, Deepak Ranjan
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supporting information
(2020/03/03)
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- A cyclometalated Ir(iii)-NHC complex as a recyclable catalyst for acceptorless dehydrogenation of alcohols to carboxylic acids
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In this work, we have synthesized two new [C, C] cyclometalated Ir(iii)-NHC complexes, [IrCp?(C∧C:NHC)Br](1a,b), [Cp? = pentamethylcyclopentadienyl; NHC = (2-flurobenzyl)-1-(4-methoxyphenyl)-1H-imidazoline-2-ylidene (a); (2-flurobenzyl)-1-(4-formylphenyl)-1H-imidazoline-2-ylidene (b)] via intramolecular C-H bond activation. The molecular structure of complex 1a was determined by X-ray single crystal analysis. The catalytic potentials of the complexes were explored for acceptorless dehydrogenation of alcohols to carboxylic acids with concomitant hydrogen gas evolution. Under similar experimental conditions, complex 1a was found to be slightly more efficient than complex 1b. Using 0.1 mol% of complex 1a, good-to-excellent yields of carboxylic acids/carboxylates have been obtained for a wide range of alcohols, both aliphatic and aromatic, including those involving heterocycles, in a short reaction time with a low loading of catalyst. Remarkably, our method can produce benzoic acid from benzyl alcohol on a gram scale with a catalyst-to-substrate ratio as low as 1?:?5000 and exhibit a TON of 4550. Furthermore, the catalyst could be recycled at least three times without losing its activity. A mechanism has been proposed based on controlled experiments and in situ NMR study.
- Borah, Dhrubajit,Das, Pankaj,Saha, Biswajit,Sarma, Bipul
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p. 16866 - 16876
(2020/12/18)
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- KMnO4-catalyzed chemoselective deprotection of acetate and controllable deacetylation-oxidation in one pot
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A novel and efficient protocol for chemoselective deacetylation under ambient conditions was developed using catalytic KMnO4. The stoichiometric use of KMnO4 highlighted the dual role of a heterogeneous oxidant enabling direct access to aromatic aldehydes in one-pot sequential deacetylation-oxidation. The reaction employed an alternative solvent system and allowed the clean transformation of benzyl acetate to sensitive aldehyde in a single step while preventing over-oxidation to acids. Use of inexpensive and readily accessible KMnO4 as an environmentally benign reagent and the ease of the reaction operation were particularly attractive, and enabled the controlled oxidation and facile cleavage of acetate in a preceding step. This journal is
- Gurawa, Aakanksha,Kumar, Manoj,Rao, Dodla S.,Kashyap, Sudhir
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p. 16702 - 16707
(2020/10/27)
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- Catalytic Selective Oxidation of Primary and Secondary Alcohols Using Nonheme [Iron(III)(Pyridine-Containing Ligand)] Complexes
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The selective oxidation of different primary and secondary alcohols to carbonyl compounds by hydrogen peroxide was found to be catalyzed in conversion ranging from good to excellent by an iron(III) complex of a pyridine-containing macrocyclic ligand (Pc-L), without the need of any additive. The choice of the counteranion (Cl, Br, OTf) appeared to be of fundamental importance and the best results in terms of selectivity (up to 99 %) and conversion (up to 98 %) were obtained using the well-characterized [Fe(III)(Br)2(Pc-L)]Br complex, 4c. Magnetic moments in solid-state, also confirmed in solution ([D6]DMSO) by Evans NMR method, were calculated and point out to an iron metal center in the high spin state of 5/2. The crystal structure shows that the iron(III) center is coordinated by the four nitrogen atoms of the macrocycle and two bromide anions to form a distorted octahedral coordination environment. The catalytic oxidation of benzyl alcohol in acetonitrile was found occurring with better conversions and selectivities than in other solvents. The reaction proved to be quite general, tolerating aromatic and aliphatic alcohols, although very low yields were obtained for terminal aliphatic alcohols. Preliminary mechanistic studies are in agreement with a catalytic cycle promoted by a high-spin iron complex.
- Caselli, Alessandro,Gallo, Emma,Panza, Nicola,Rizzato, Silvia,Tseberlidis, Giorgio,di Biase, Armando
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supporting information
p. 6635 - 6644
(2020/10/30)
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- Clean and Selective Oxidation of Alcohols with Oxone and Phase-Transfer Catalysts in Water
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Abstract: A new, simple, metal-free, and eco-friendly procedure has been proposed forthe oxidation of alcohols with Oxone (potassium peroxymonosulfate) in water inthe presence of six phase-transfer catalysts (PTC). Phase-transfer catalystswere found to display high catalytic activity in water solution. Furthermore,the oxidation of alcohols was also carried out with relatively good conversionand selectivity in water without any catalyst.
- An, X. Q.,Kang, M.,Ma, H. C.,Yang, Y. X.,Yang, Z. W.,Zeng, W.
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p. 1790 - 1794
(2020/12/01)
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- Carbon dots as photocatalysts for organic synthesis: Metal-free methylene-oxygen-bond photocleavage
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We report for the first time that irradiation of four different citric acid-derived carbon dots (CDs), in the absence of any other redox mediators, promotes an organic reaction. In this proof-of-concept study methylene-oxygen bond reductive photocleavage in N-methyl-4-picolinium esters is demonstrated. Cyclic voltammetry and UV-Vis spectra of the CDs and of the esters indicate that photocleavage reactivity correlates with the redox properties and the relative energies expressed in the Fermi scale. A photo-fragmentation mechanism is proposed. This study offers a new possibility to employ inexpensive and readily available CDs to promote photo-organic reactions.
- Cailotto, Simone,Negrato, Matteo,Daniele, Salvatore,Luque, Rafael,Selva, Maurizio,Amadio, Emanuele,Perosa, Alvise
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p. 1145 - 1149
(2020/03/11)
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- Platinum on carbon–catalyzed and chemoselective aqueous oxygen oxidation of aromatic acetals to benzoic acids
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Novel chemoselective transformations can diversify the synthetic pathways of the target molecules. The chemoselective oxidation of aromatic acetals to benzoic acid derivatives under platinum on carbon (Pt/C)–catalyzed oxygen oxidation conditions has been newly developed with a tolerance of aliphatic acetals and ketals. The present oxidation was clean and useful from the viewpoint of the easy removal of Pt/C and the use of molecular oxygen as a green oxidant in water as an abundant, non-toxic and environmentally friendly solvent.
- Yasukawa, Naoki,Matsuda, Takumi,Shimizu, Eisho,Sajiki, Hironao,Sawama, Yoshinari
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p. 145 - 152
(2020/01/28)
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- Deep eutectic solvent-catalyzed Meyer-Schuster rearrangement of propargylic alcohols under mild and bench reaction conditions
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The Meyer-Schuster rearrangement of propargylic alcohols into α,β-unsaturated carbonyl compounds has been revisited by setting up an atom-economic process catalyzed by a deep eutectic solvent FeCl3·6H2O/glycerol. Isomerizations take place smoothly, at room temperature, under air and with short reaction times. The unique solubilizing properties of the eutectic mixture enabled the use of a substrate concentration up to 1.0 M with the medium being recycled up to ten runs without any loss of catalytic activity. This journal is
- Ríos-Lombardía, Nicolás,Cicco, Luciana,Yamamoto, Kota,Hernández-Fernández, José A.,Morís, Francisco,Capriati, Vito,García-álvarez, Joaquín,González-Sabín, Javier
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supporting information
p. 15165 - 15168
(2020/12/21)
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- Method for preparing organic acid by oxidative cleavage of aromatic secondary alcohol
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The invention relates to a method for preparing organic acids by oxidation of aromatic secondary alcohols. With air or oxygen as an oxygen source, a copper salt and an organic ligand as catalysts, aninorganic alkali is added, and aromatic secondary alcohols are subjected to carbon-carbon bond oxidative cracking to obtain the organic acids. The method has the advantages of high oxidation efficiency and high product yield; with the use of air or oxygen as the oxygen source, the method is economical and environmentally friendly and has good application prospects.
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Paragraph 0043-0046; 0051
(2020/09/16)
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- Exploration of New Biomass-Derived Solvents: Application to Carboxylation Reactions
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A range of hitherto unexplored biomass-derived chemicals have been evaluated as new sustainable solvents for a large variety of CO2-based carboxylation reactions. Known biomass-derived solvents (biosolvents) are also included in the study and the results are compared with commonly used solvents for the reactions. Biosolvents can be efficiently applied in a variety of carboxylation reactions, such as Cu-catalyzed carboxylation of organoboranes and organoboronates, metal-catalyzed hydrocarboxylation, borocarboxylation, and other related reactions. For many of these reactions, the use of biosolvents provides comparable or better yields than the commonly used solvents. The best biosolvents identified are the so far unexplored candidates isosorbide dimethyl ether, acetaldehyde diethyl acetal, rose oxide, and eucalyptol, alongside the known biosolvent 2-methyltetrahydrofuran. This strategy was used for the synthesis of the commercial drugs Fenoprofen and Flurbiprofen.
- Gevorgyan, Ashot,Hopmann, Kathrin H.,Bayer, Annette
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p. 2080 - 2088
(2020/02/20)
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