- 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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- Aminomethylation of Aryl Bromides by Nickel-Catalyzed Electrochemical Redox Neutral Cross Coupling
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We develop an electrochemical nickel-catalyzed aminomethylation of aryl bromides under mild conditions. The convergent paired electrolysis makes full use of anode and cathode processes, free of a terminal oxidant, a sacrificial anode, a metal reductant, and a prefunctionalized radical precursor. In addition, this method exhibits wide functional group tolerance (63 examples), including some sensitive substituents and aromatic heterocycles. This redox neutral cross coupling provides a more environmentally friendly and synthetic practical protocol for forging C(sp2)–C(sp3) bonds.
- Ma, Yueyue,Hong, Jufei,Yao, Xiantong,Liu, Chengyu,Zhang, Ling,Fu, Youtian,Sun, Maolin,Cheng, Ruihua,Li, Zhong,Ye, Jinxing
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supporting information
p. 9387 - 9392
(2021/12/17)
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- 1,2-Dibutoxyethane-Promoted Oxidative Cleavage of Olefins into Carboxylic Acids Using O2 under Clean Conditions
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Herein, we report the first example of an effective and green approach for the oxidative cleavage of olefins to carboxylic acids using a 1,2-dibutoxyethane/O2 system under clean conditions. This novel oxidation system also has excellent functional-group tolerance and is applicable for large-scale synthesis. The target products were prepared in good to excellent yields by a one-pot sequential transformation without an external initiator, catalyst, and additive.
- Ou, Jinhua,Tan, Hong,He, Saiyu,Wang, Wei,Hu, Bonian,Yu, Gang,Liu, Kaijian
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p. 14974 - 14982
(2021/10/25)
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- Cleavage of Carboxylic Esters by Aluminum and Iodine
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A one-pot procedure for deprotecting carboxylic esters under nonhydrolytic conditions is described. Typical alkyl carboxylates are readily deblocked to the carboxylic acids by the action of aluminum powder and iodine in anhydrous acetonitrile. Cleavage of lactones affords the corresponding ω-iodoalkylcarboxylic acids. Aryl acetylates undergo deacetylation with the participation of the neighboring group. This method enables the selective cleavage of alkyl carboxylic esters in the presence of aryl esters.
- Sang, Dayong,Yue, Huaxin,Fu, Yang,Tian, Juan
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p. 4254 - 4261
(2021/03/09)
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- Triple-phase Boundary in Anion-Exchange Membrane Reactor Enables Selective Electrosynthesis of Aldehyde from Primary Alcohol
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Oxidation of primary alcohol to the corresponding aldehyde remains a significant challenge, even with the state-of-the-art chemistry. Here, a novel electrochemical system was developed for the exclusive production of aldehyde from primary alcohol using an anion-exchange membrane (AEM) reactor. Oxidation proceeded on a gold catalyst under basic conditions, which largely enhanced the reaction rate. Despite the basic nature around the reaction sites, the oxidation of primary alcohols exclusively yielded the corresponding aldehyde, which was attributed to the unique three-phase interfacial reaction sites in the AEM reactor. In addition to benzyl alcohol, the oxidation of allylic and aliphatic alcohols was also demonstrated. Comparison of constant potential electrolysis with the AEM reactor or a conventional batch-type cell revealed the crucial role of the triple-phase boundary for the selectivity of the oxidation of alcohol.
- Atobe, Mahito,Fukazawa, Atsushi,Furutani, Yuka,Ido, Yuto,Sato, Yasushi,Shida, Naoki
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- PROCESS FOR PREPARING CARBAMOYLOXYMETHYL TRIAZOLE CYCLOHEXYL ACID COMPOUNDS
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Improved methods and intermediates thereof for preparing carbamoyloxy methyl triazole cyclohexyl acid compounds are described. These compounds are useful as LPA antagonists. Formula (I).
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- Boosting multiple photo-assisted and temperature controlled reactions with a single redox-switchable catalyst: Solvents as internal substrates and reducing agent
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An alternative and economically viable process for the synthesis of β-aryl enals, enones and the aryl amines has been developed by partial oxidation of ethanol, isopropanol and N, N-dimethyl formamide (DMF). The formation of β-aryl enals, enones and the aryl amines was catalyzed by a mixed metal oxides layer of cobalt and chromium supported on halloysite nanotubes, designated as CoCr2O4-HNT. The C[sbnd]C and C[sbnd]N bond formation reactions were found to be influenced by temperature and the nature of base. The condensation of aldehyde with in situ generated acetaldehyde by ethanol oxidation forming β-aryl enals occurred selectively at 120 °C. The partial oxidation of isopropanol to acetone and its condensation with aldehydes forming β-aryl enones occurred at room temperature. Increase in temperature caused the liberation of hydrogen gas from isopropanol and allowed the reversible reduction of aldehydes to alcohols. Increase in temperature in isopropanol and increase in base concentration in ethanol causes the selective reduction of aldehydes to alcohols. Besides being active for the Claisen-Schmidt type of reactions and the aryl halides amination process, the synthesized catalyst was also found to be highly active for the photocatalytic oxidation of benzyl alcohols in absence of any external oxidizing agent. The positive holes (h+) generated at the Co(II) site as evident from EPR analysis was considered to be responsible for high photocatalytic activity of the material reducing the recombination rate of holes and electrons (e?). Density Functional Theory calculations were performed to understand the mechanism of ethanol oxidation to acetaldehyde.
- Bania, Kusum K.,Baruah, Manash J.,Bhattacharyya, Pradip K.,Das, Biraj,Karunakar, Galla V.,Roy, Subhasish,Saikia, Lakshi,Saikia, Pinku,Sharma, Mukesh
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p. 104 - 121
(2020/06/01)
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- Cobalt-Catalyzed Reductive Carboxylation of Aryl Bromides with Carbon Dioxide
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Cobalt-catalyzed reductive carboxylation of aryl bromides with carbon dioxide has been developed. The reaction proceeded under one atm pressure of CO2 at 40 °C in the presence of cobalt iodide/2,2′-bipyridine catalysts and zinc dust as a reducing reagent. Various aryl bromides could be converted to the corresponding carboxylic acids in good to high yields. Preliminary mechanistic experiments ruled out intervention of intermediate organozinc species for carboxylation with CO2, thus suggesting a direct CO2 insertion into the corresponding ArCoBr species. (Figure presented.).
- Hang, Wei,Yi, Yaping,Xi, Chanjuan
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supporting information
p. 2337 - 2341
(2020/04/30)
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- Acceptorless dehydrogenative oxidation of primary alcohols to carboxylic acids and reduction of nitroarenes via hydrogen borrowing catalyzed by a novel nanomagnetic silver catalyst
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A novel silver nano magnetic catalyst was devised for dehydrogenative oxidation of aromatic and aliphatic alcohols to the corresponding acid with water as the sole oxygen source and hydrogen gas as the only by-product. The designed catalytic system advantages from easy recovery of magnetic materials i.e. magnetic decantation, being economically viable and environmentally friendly. Furthermore, the catalytic reaction is able to reduce aryl nitro compounds in the absence of any reducing agent.
- Yazdani, Elahe,Heydari, Akbar
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supporting information
(2020/08/14)
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- Cr(VI) oxidation using cetylpicolinium dichromate: Kinetics of oxidation of benzaldehydes with a green protocol
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Oxidation kinetics of benzaldehyde and some of its ortho- and para-monosubstituted derivatives have been studied using cetylpicolinium dichromates, a class of novel phase transfer oxidants, in dichloromethane medium. The rate of reaction is first order with respect to oxidant and fractional order with respect to the substrates. The Michaelis–Menten type oxidation was observed with respect to the substrates. Benzaldehydes are found to be oxidized to their corresponding acids. The mechanism of oxidation reaction has been suggested based on the solvent isotope effect, Hammett plot, and thermodynamic study. The solvent isotope effect (kCHCl3/kCDCl3=?1.57) indicates the involvement of hydrogen exchange with the medium during oxidation reactions. A strong influence of specific solute–solvent interactions on the rate of the reaction is observed. Both the electron-withdrawing and electron-releasing substituents on the substrates accelerate the rate of reaction.
- Priyadarshini, Supriya,Dash, Sukalyan
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p. 105 - 111
(2018/11/27)
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- Method for copper-catalyzed carboxylation reaction of arylboronic acid and carbon dioxide
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The invention discloses a method for a copper-catalyzed carboxylation reaction of arylboronic acid and carbon dioxide. According to the method, carbon dioxide is used as a C1 source, copper catalysisis adopted, alkoxide serves as alkali, and a reaction is carried out in an organic solvent; the method is simple in process and easy to implement, and shows wide functional group compatibility; the method allows various arylboronic acids such as monosubstituted or polysubstituted phenylboronic acid, polycyclic aromatic hydrocarbon boronic acid and benzoheterocyclic boronic acid to be converted into corresponding arylcarboxylic acids with considerable yield under mild conditions; and the produced carboxylic acids have important application value, and can be used for deriving a great number of other common chemical substances, such as acyl halide, acid anhydride, ester and amide.
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Paragraph 0057; 0058
(2019/12/29)
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- UiO-type metal-organic frameworks with NHC or metal-NHC functionalities for: N-methylation using CO2 as the carbon source
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We demonstrate the first metal-organic framework (MOF) that catalyzes N-methylation of amines using 1 atm CO2 and phenylsilane under ambient conditions. Compared with its homogeneous analog, the incorporation of N-heterocyclic carbene (NHC) into the MOF provides more efficient catalysis with improved reaction kinetics, turnover numbers and recyclability. Moreover, the metalated NHC functionalized MOF achieves direct N-methylation of amines bearing carboxylate moieties, which are common building blocks in pharmaceutical chemistry.
- Zhang, Xu,Jiang, Yilin,Fei, Honghan
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supporting information
p. 11928 - 11931
(2019/10/11)
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- Palladium complex containing diphosphine m-carborane ligand as well as preparation and application of palladium complex
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The invention relates to a palladium complex containing a diphosphine m-carborane ligand as well as a preparation and an application of the palladium complex. The preparation method of the palladium complex comprises the following steps of 1) adding an n-BuLi solution into a m-carborane solution, and then reacting for 30-60 minutes at a room temperature; 2) adding diphenyl phosphorus chloride, andreacting for 3-6 h at the room temperature; and 3) adding PdCl2, reacting at the room temperature for 3-5 hours, and carrying out post-treatment to obtain the palladium complex. The palladium complexis used for catalyzing the reaction of halohydrocarbon with carbon dioxide to synthesize carboxylic acid. Compared with the prior art, the synthesis process is simple and green, and has the excellentselectivity and high yield; the palladium complex has the stable physicochemical properties and is used as the catalyst, the halogenated hydrocarbon is used as a substrate, the palladium complex andthe halogenated hydrocarbon are jointly dissolved in toluene, and the carbon dioxide is introduced at the normal pressure for reaction, so that the corresponding carboxylic acid can be synthesized athigh yield.
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Paragraph 0047-0050
(2019/12/02)
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- Fe3O4@SiO2@Im[Cl]Mn(III)-complex as a highly efficient magnetically recoverable nanocatalyst for selective oxidation of alcohol to imine and oxime
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An efficient and environmentally friendly oxidation process for the one-pot preparation of oxime, imine and carbonyl compounds through alcohol oxidation in the presence of H2O2 and/or O2 have been developed by a melamine-Mn(III) Schiff base complex supported on Fe3O4@SiO2–Cl nanoparticles, named as Fe3O4@SiO2@Im[Cl]Mn(III)-complex nanocomposite, at room temperature. Direct oxidation of alcohol to carboxylic acid was performed using the catalyst in the presence of molecular O2 at room temperature in a different approach. The oxidation products were obtained with excellent yields and high TOFs. The properties of the catalyst were characterized by Fourier transform infrared spectroscopy (FTIR), elemental analysis (C, H, N), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS), energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), inductive coupled plasma (ICP), cyclic voltammetry (CV), nuclear magnetic resonance (1H & 13C NMR), vibration sample magnetometer (VSM), Brunauer– Emmett–Teller (BET) and differential pulse voltammetry (DPV) analyses. The mechanism of the oxidation processes was investigated for the both H2O2 and O2 oxidants. The role of the imidazolium moiety in the catalyst as a secondary functionality was investigated. Chemoselectivity behavior of the catalyst was studied by some combinations. The catalyst could be recycled from the reaction mixture by a simple external magnet and reused for several times without any considerable reactivity loss.
- Kazemnejadi, Milad,Alavi, Seyyedeh Ameneh,Rezazadeh, Zinat,Nasseri, Mohammad Ali,Allahresani, Ali,Esmaeilpour, Mohsen
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p. 230 - 249
(2019/03/28)
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- Application of metallide/palladium compound catalytic reduction system in reaction of removing allyl groups and deuteration reaction
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The invention discloses application of a metallide/palladium compound catalytic reduction system in reaction of removing allyl groups of a compound containing the allyl groups and deuteration reaction. The reaction comprises the following steps: under protection of nitrogen gas, suspending a palladium compound and a metallide in a solvent, stirring for 5 minutes, adding the compound containing theallyl groups, reacting for 0.5-36 hours at the temperature of minus 50-120 DEG C, adding ice water to stop reaction, regulating a pH value to 3.5 by using diluted hydrochloric acid, and carrying outsolvent extraction, drying by steaming and column-chromatography purification on reaction liquid to finish the reaction.
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Paragraph 0042
(2018/07/30)
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- Pd-Catalyzed debenzylation and deallylation of ethers and esters with sodium hydride
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Herein we demonstrate simply that the addition of Pd(OAc)2 as a promotor switches the reactivity of a commonly used base NaH to a nucleophilic reductant. The reactivity is engineered into a palladium-catalyzed reductive debenzylation and deallylation of aryl ethers and esters. This operationally simple, mild protocol displays a broad substrate scope and a broad spectrum of functional group tolerance (>50 examples) and high chemoselectivity toward aryl ethers over aliphatic structures. Moreover, the dual reactivity of NaH as a base and a reductant is demonstrated in efficient synthetic elaboration.
- Mao, Yujian,Liu, Ye,Hu, Yanwei,Wang, Liang,Zhang, Shilei,Wang, Wei
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p. 3016 - 3020
(2018/04/14)
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- Palladium-catalyzed oxidative coupling of arylboronic acid with isocyanide to form aromatic carboxylic acids
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A valuable palladium-catalyzed oxidative coupling of aryl- and alkenyl borides with isocyanide for the synthesis of corresponding carboxylic acids has been developed. With wide substrate scopes and good functional group tolerance, this reaction offers corresponding carboxylic acids in moderate to excellent yields.
- Chen, Zhen-Bang,Liu, Kui,Zhang, Fang-Ling,Yuan, Qing,Zhu, Yong-Ming
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p. 8078 - 8083
(2017/10/10)
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- Copper (II)-catalysed direct conversion of aldehydes into nitriles in acetonitrile
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A mild one-pot method for the direct conversion of aryl, heteroaryl and alkyl aldehydes into nitriles was achieved by forming the corresponding oximes in situ with NH2OH and allowing them to react with CuO and acetonitrile. Yields of the 13 nitriles prepared were moderate to very good (62–91%).
- Ma, Xiaoyun,Ao, Jun,Chen, Zhengjian,Liu, Yi
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p. 465 - 468
(2017/08/18)
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- Preparation method of amboryl ester type sugar marker with permanent charges and application
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The invention provides a preparation method of an amboryl ester type sugar marker with permanent charges and belongs to the technical field of organic synthesis and bioinformation. The amboryl ester type sugar marker with permanent charges is prepared from benzocaine through a series of synthesis, has the advantages that the reaction conditions (45 DEG C for 40 min) are mild, detection sensitivity can be improved and deviation yield is high, the deviation yield reaches 98%, the product can be detected with HPLC (high-performance liquid chromatography and MS (mass spectrometry) (ESI-MS and MALDI-ToF-MS), and the sensitivity is high.
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Paragraph 0019
(2017/12/27)
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- Development of an indirect spectrophotometric method for determination of methamidophos insecticide in soil, water and vegetable samples
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A simple and rapid indirect spectrophotometric method for determination of methamidophos in water, soil and vegetable samples has been described. Methamidophos reacts with acid produced from p-dimethylaminobenzaldehyde (p-DMAB) as a result of Cannizaro's reaction. The resultant adduct undergoes condensation reaction in acidic medium forming a yellow colored product. Absorbance of the colored product was measured at 405 nm and pH 3 against a reagent blank. The Beer's law range is obeyed in the range 1-30 μg mL-1 with molar absorptivity of 2.8 ×103 L mol-1 cm-1. The limit of detection and quantification were found to be 0.20±0.03 and 0.60±0.04 μg mL-1 respectively. The proposed method was effectively applied for determination of methamidophos in various samples with percent recoveries in the range of 96±0.08 to 102±0.06%.
- Shah, Jasmin,Jan, M. Rasul,Muhammad, Mian,Ara, Behisht,Ur Rehman, Ibadat
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p. 311 - 318
(2015/07/27)
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- Efficient and convenient oxidation of aldehydes and ketones to carboxylic acids and esters with H2O2 catalyzed by Co4HP2Mo15V3O62 in ionic liquid [TEBSA][BF4]
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A simple, efficient, and eco-friendly procedure for the oxidation of aldehydes and ketones to carboxylic acids and esters with H2O2 catalyzed by Co4HP2Mo15V3O62 in ionic liquid [TEBSA][BF4] has been developed. This atom-economical protocol affords the target products in good to high yields. The products can be separated by a simple extraction with organic solvent, and the catalytic system can be recycled and reused without loss of catalytic activity. Additionally, the possible mechanism of oxidation in the catalytic system is proposed. This journal is
- Hu, Yu-Lin,Li, De-Jiang,Li, Dong-Sheng
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p. 24936 - 24943
(2015/03/30)
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- A high-throughput screening method for determining the substrate scope of nitrilases
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Nitrile compounds are intermediates in the synthesis of pharmaceuticals such as atorvastatin. We have developed a chromogenic reagent to screen for nitrilase activity as an alternative to Nessler's reagent. It produces a semi-quantifiable blue colour and hydrolysis of 38 nitrile substrates by 23 nitrilases as cell-free extracts has been shown. This journal is
- Black, Gary W.,Brown, Nicola L.,Perry, Justin J. B.,Randall, P. David,Turnbull, Graeme,Zhang, Meng
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supporting information
p. 2660 - 2662
(2015/03/05)
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- Electrophilicity and nucleophilicity of commonly used aldehydes
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The present approach for determining the electrophilicity (E) and nucleophilicity (N) of aldehydes includes a kinetic study of KMNO4 oxidation and NaBH4 reduction of aldehydes. A transition state analysis of the KMNO4 promoted aldehyde oxidation reaction has been performed, which shows a very good correlation with experimental results. The validity of the experimental method has been tested using the experimental activation parameters of the two reactions. The utility of the present approach is further demonstrated by the theoretical versus experimental relationship, which provides easy access to E and N values for various aldehydes and offers an at-a-glance assessment of the chemical reactivity of aldehydes in various reactions. the Partner Organisations 2014.
- Pratihar, Sanjay
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supporting information
p. 5781 - 5788
(2014/07/22)
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- Direct carboxylation of simple arenes with CO2 through a rhodium-catalyzed C-H bond activation
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Direct carboxylation of simple arenes under atmospheric pressure of CO2 is achieved through a rhodium-catalyzed C-H bond activation without the assistance of a directing group. Various arenes such as benzene, toluene, xylene, electron-rich or electron-deficient benzene derivatives, and heteroaromatics are directly carboxylated with high TONs. This journal is
- Suga, Takuya,Mizuno, Hajime,Takaya, Jun,Iwasawa, Nobuharu
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supporting information
p. 14360 - 14363
(2015/02/19)
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- Nickel-catalysed carboxylation of organoboronates
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A nickel/N-heterocyclic carbene (NHC) catalysed carboxylation of aryl-, heteroaryl- and alkenylboronates, affording the corresponding carboxylic acids, has been developed. This transformation proceeds under one atmosphere of CO 2 with a broad range of substrates and exhibits good functional group compatibility. the Partner Organisations 2014.
- Makida, Yusuke,Marelli, Enrico,Slawin, Alexandra M. Z.,Nolan, Steven P.
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p. 8010 - 8013
(2014/07/08)
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- Continuous flow synthesis of ketones from carbon dioxide and organolithium or grignard reagents
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We describe an efficient continuous flow synthesis of ketones from CO 2 and organolithium or Grignard reagents that exhibits significant advantages over conventional batch conditions in suppressing undesired symmetric ketone and tertiary alcohol byproducts. We observed an unprecedented solvent-dependence of the organolithium reactivity, the key factor in governing selectivity during the flow process. A facile, telescoped three-step-one-flow process for the preparation of ketones in a modular fashion through the in-line generation of organometallic reagents is also established.
- Wu, Jie,Yang, Xiaoqing,He, Zhi,Mao, Xianwen,Hatton, T. Alan,Jamison, Timothy F.
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supporting information
p. 8416 - 8420
(2014/08/18)
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- Oxidation of aromatic aldehydes with potassium bromate-bromide reagent and an acidic catalyst
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We report herein an easy oxidation procedure for converting aromatic aldehydes to aromatic carboxylic acids by use of a combination of commercially and readily available potassium bromate with potassium bromide in the presence of hydrochloric acid catalyst.
- Sharma,Robert, Alice R.
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p. 3251 - 3254
(2013/09/23)
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- Kinetics and mechanism of the oxidation of substituted benzaldehydes with bis(pyridine)silver permanganate
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The oxidation of thirty-six ortho-, meta- and para-substituted benzaldehydes by bis(pyridine)silver permanganate (BPSP) resulted in the formation of the corresponding benzoic acids. The reaction is first order with respect to both BPSP and aldehydes. The reaction is catalyzed by hydrogen ions. The rate of reaction increases with an increase in the amount of acetic acid in the solvent. The correlation analyses of the rate of oxidation of thirty-six aldehydes were performed in terms of Charton's LDR and LDRS equations. The rate of oxidation of meta- and para-substituted benzaldehydes showed excellent correlation with Charton's LDR equation. The rates of ortho-compounds showed excellent correlation with LDRS equation. The oxidation para-compounds is more susceptible to the delocalization effect. The oxidation of ortho- and meta-compounds exhibited a greater dependence on the field effect. The polar reaction constants are negative indicating an electron-deficient centre in the rate-determining step. A mechanism involving a nucleophilic attack on the carbonyl group by a permanganate-oxygen and a subsequent hydride transfer has been proposed.
- Purohit, Trupti,Banerji, Jayshree,Kotai, Laszlo,Sajo,Banerji,Sharma, Pradeep K.
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p. 1045 - 1052
(2013/01/14)
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- Cu(II) bromide catalyzed oxidation of aldehydes and alcohols
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A variety of aromatic, aliphatic and conjugated aldehydes and alcohols were transformed to the corresponding carboxylic acids and ketones with a quantitative conversion in high yields with 70% t-BuOOH solution in water in the presence of catalytic (5 mol%) amounts of CuBr2 under room temperature conditions. The conversion of 4-methoxybenzaldehyde to 4-methoxybenzoic acid is extremely facile in MeCN at ambient temperature in the presence of 5 mol% CuBr2 and 2 equiv. 70% t-BuOOH (water) as the oxidant. Oxidation with t-BuOOH (water) alone in MeCN was found to be negligible. The scope of our catalytic system is applicable for a wide range of aromatic, conjugated and aliphatic substrates. These aldehydes were converted to the corresponding carboxylic acids in good isolated yields in reasonable times. It is pertinent to mention here that mild halogenic oxidants like hypochlorites, chlorites and NBS are not suitable for substrates with electron-rich aromatic rings, olefinic bonds and secondary hydroxyl groups. Substitutions at different positions on the phenyl ring do not hinder the reaction, although the reaction time is affected. Oxidation of α,β unsaturated derivatives resulted in the formation of the expected acid in good yield. In addition, the transformation of secondary alcohols to ketones is extremely facile. No recemization was observed for menthone. This method possesses a wide range of capabilities since it can be used with other functional groups which may not tolerate oxidative conditions, involves fairly simple method for work-up, exhibits chemoselectivity and proceeds under ambient conditions. The resulting products are obtained in good yields within reasonable time.
- Das, Rima,Chakraborty, Debashis
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experimental part
p. 437 - 442
(2012/01/30)
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- Mohr's salt catalyzed oxidation of aldehydes with t-BuOOH
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Various aromatic, aliphatic and conjugated aldehydes were transformed to the corresponding carboxylic acids with 70% t-BuOOH solution (water) in the presence of catalytic amounts (10 mol%) of Mohr's salt. This method possesses functional group compatibility, does not involve cumbersome work-up, exhibits chemoselectivity since other functional groups remain intact and proceeds under mild conditions. The resulting products are obtained in good yields within reasonable times. Copyright
- Chakraborty, Debashis,Majumder, Chandrima,Malik, Payal
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experimental part
p. 487 - 490
(2012/04/04)
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- Ceric ammonium nitrate catalyzed oxidation of aldehydes and alcohols
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A variety of aromatic, aliphatic and conjugated aldehydes and alcohols were transformed to the corresponding carboxylic acids and ketones with a quantitative conversion in high yields with 70% t-BuOOH solution in water in the presence of catalytic amounts of ceric ammonium nitrate [Ce(NH 4)2(NO3)6] (CAN) under room temperature conditions. The scope of our catalytic system is applicable for a wide range of aromatic, conjugated and aliphatic substrates. These aldehydes were converted to the corresponding carboxylic acids in good isolated yields in reasonable times. This method possesses a wide range of capabilities since it can be used with other functional groups which may not tolerate oxidative conditions, involves fairly simple method for work-up, exhibits chemoselectivity and proceeds under ambient conditions. The resulting products are obtained in good yields within reasonable time.
- Gowda, Ravikumar R.,Chakraborty, Debashis
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experimental part
p. 2379 - 2384
(2012/02/15)
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- Structure-Reactivity correlation in the oxidation of substituted benzaldehydes by tetraethylammonium chlorochromate
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Oxidation of 36 monosubstituted benzaldehydes by tetraethylammonium chlorochromate in dimethyl sulphoxide, leads to the formation of corresponding benzoic acids. The reaction is of first order with respect to chlorochromate and aldehydes. The reaction is promoted by H+; the H+ dependence has the form kobs = a + b[H+]. The oxidation of duteriated benzaldehyde exhibits substantial primary kinetic isotope effect. The reaction was studied in 19 different organic solvents and the effect of solvent was analyzed using Taft's and Swain's multiparametric equations. The rates of the oxidation of para- and meta-substituted benzaldehydes showed excellent correlation in terms of Charton's triparametric LDR equation, whereas the oxidation of ortho-substituted benzaldehydes were correlated well with tetraperametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalized effect than is the oxidation of ortho- and meta- substituted compounds, which display a greater dependence on the field effect. The positive value of h suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the orthosubstituents. A suitable mechanism has been proposed.
- Gehlot,Prasadrao,Sharma
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experimental part
p. 1173 - 1178
(2012/01/05)
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- Hydrolysis of 1-(X-substituted-benzoyl)-4-aminopyridinium ions: Effect of substituent X on reactivity and reaction mechanism
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A kinetic study is reported for hydrolysis of 1-(X-substituted-benzoyl)-4- aminopyridinium ions 2a-i, which were generated in situ from the nucleophilic substitution reaction of 2,4-dinitrophenyl X-substituted-benzoates 1a-i with 4-aminopyridine in 80 mol% H2O/20 mol% DMSO at 25.0 ± 0.1 °C. The plots of pseudo-first-order rate constants kobsdvs. pyridine concentration are linear with a large positive intercept, indicating that the hydrolysis of 2a-i proceeds through pyridine-catalyzed and uncatalyzed pathways with the rate constant kcat and ko, respectively. The Hammett plots for kcat and ko consist of two intersecting straight lines, which might be taken as evidence for a change in the rate-determining step (RDS). However, it has been proposed that the nonlinear Hammett plots are not due to a change in the RDS but are caused by stabilization of 2a-i in the ground state through a resonance interaction between the π-electron-donor substituent X and the carbonyl functionality. This is because the corresponding Yukawa-Tsuno plots exhibit excellent linear correlations with ρX = 1.45 and r = 0.76 for kcat while ρX = 1.39 and r = 0.72 for ko. A possibility that the hydrolysis of 2a-i proceeds through a concerted mechanism has been ruled out on the basis of the large ρX values. Thus, the reaction has been concluded to proceed through a stepwise mechanism in which the leaving group departs after the RDS since OH- is more basic and a poorer nucleofuge than 4-aminopyridine. The Royal Society of Chemistry 2011.
- Um, Ik-Hwan,Kim, Eun-Hee,Kang, Ji-Sun
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p. 8062 - 8067
(2012/01/04)
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- Process for the carboxylation of aryl halides with palladium catalysts
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A process for the carboxylation of an aryl halide to yield an aryl carboxylic acid, in which the aryl halide and CO2 are contacted in an organic solvent under inert atmosphere and in the presence of a reducing agent and an adequate catalyst system.
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Page/Page column 8
(2011/05/04)
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- An efficient FeCl3-promoted O-alkyl cleavage of esters to carboxylic acids
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A reliable and practical procedure for FeCl3-promoted ester cleavage has been developed. Lewis acids including TiCl4, ZnO and FeCl3 etc. were investigated as promoters for O-alkyl cleavage of carboxylic acid ester. Under optimal reaction conditions, FeCl3 (1.5 equiv.) was found to possess the highest activity and efficiently enhanced dealkylation of aryl esters, alkyl esters and aromatic heterocyclic esters to give their corresponding carboxylic acids in 54-98% yield, the method provides a complementary access to dealkylation of ester under neutral condition.
- Lian, Xiaoyan,Fu, Shaomin,Ma, Tongmei,Li, Shunbin,Zeng, Wei
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experimental part
p. 443 - 447
(2012/02/03)
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- Bi2O3-catalyzed oxidation of aldehydes with t-BuOOH
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A variety of aromatic, aliphatic and conjugated aldehydes were transformed to the corresponding carboxylic acids with 70% t-BuOOH solution (water) in the presence of catalytic amounts of Bi2O3. This method possesses a wide range of capabilities, does not involve cumbersome work-up, exhibits chemoselectivity and proceeds under mild conditions. The resulting products are obtained in good yields within reasonable time. The overall method is green.
- Malik, Payal,Chakraborty, Debashis
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supporting information; experimental part
p. 3521 - 3523
(2010/08/22)
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- Pd/C and NaBH4 in basic aqueous alcohol: An efficient system for an environmentally benign oxidation of alcohols
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We report the oxidation of a wide range of alcohols using an environmentally benign and economical process. The use of Pd/C heterogeneous catalysts along with NaBH4in aqueous ethanol or methanol and either K2CO3 or KOH as base at room temperature under molecular oxygen or air give the corresponding oxidation products. This protocol is versatile since it is capable of oxidizing alcohols to its desired carbonyl or carboxyl counterpart. Room temperature reaction in aqueous system and recyclability of the catalyst are among the advantages of this manipulation. These advantages make the process safe and cheaper rendering it favorable from both economic and environmental viewpoints. Georg Thieme Verlag Stuttgart New York.
- An, Gwangil,Ahn, Hyunseok,De Castro, Kathlia A.,Rhee, Hakjune
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experimental part
p. 477 - 485
(2010/06/13)
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- Bismuth(III) oxide catalyzed oxidation of alcohols with tert-butyl hydroperoxide
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A variety of aromatic, aliphatic and conjugated alcohols were transformed into the corresponding carboxylic acids and ketones with aq 70% t-BuOOH in the presence of catalytic amounts of bismuth(III) oxide. This method possesses a wide range of capabilities, does not involve cumbersome work-up, exhibits chemoselectivity and proceeds under ambient conditions. The resulting products are obtained in good yields within reasonable time. The overall method is green.
- Malik, Payal,Chakraborty, Debashis
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experimental part
p. 3736 - 3740
(2011/01/03)
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- Silver nitrate-catalyzed oxidation of aldehydes to carboxylic acids by H2O2
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A variety of aromatic, aliphatic and conjugated aldehydes were converted to the corresponding carboxylic acid derivatives with 30% H2O 2 as the oxidant in the presence of catalytic amounts of AgNO 3. The method described has wide range of applicabilities, does not involve cumbersome work-up, exhibits chemoselectivity and proceeds under mild reaction conditions, and the resulting products are obtained in good yields within reasonable time.
- Chakraborty, Debashis,Gowda, Ravikumar R.,Malik, Payal
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experimental part
p. 6553 - 6556
(2011/02/21)
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- Correlation analysis of reactivity in the oxidation of substituted benzaldehydes by morpholinium chlorochromate
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Oxidation of thirty six monosubstituted benzaldehydes by morpholinium chlorochromate (MCC) in dimethylsulphoxide (DMSO), leads to the formation of corresponding benzoic acids. The reaction is of first order with respect to MCC. A Michaelis-Menten type kinetics is observed with respect to benzaldehydes. The reaction is promoted by hydrogen ions; the hydrogen-ion dependence has the form kobs = a + b [H+]. The oxidation of [2H] benzaidehyde (PhCDO) exhibited a substantial primary kinetic isotope effect. The reaction was studied in nineteen organic solvents and the effect of solvent was analysed using Taft's and Swain's multi-parametric equations. The rates of the oxidation of para- and meta-substituted benzaldehydes showed excellent correlation in terms of Charton's triparametric LDR equation, whereas the oxidation of ortho-substituted benzaldehydes were correlated well with tetraparametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalized effect than is the oxidation of ortho- and meta-substituted compounds, which display a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the ortho-substituents. A suitable mechanism has been proposed.
- Choudhary, Anurag,Malani,Agarwal,Sharma,Sharma, Vinita
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experimental part
p. 927 - 935
(2010/07/16)
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- Palladium-catalyzed direct carboxylation of aryl bromides with carbon dioxide
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(Chemical Equation Presented) A novel protocol for the direct carbon dioxide insertion (CO2) into aryl halides in a catalytic manner is presented herein. Unlike other carboxylation methods using CO2, there is no need for the synthesis of the corresponding organometallic intermediates. Additionally, and in contrast to the well-established carbonylation processes, our protocol does not use highly toxic CO for the preparation of benzoic acids. Furthermore, this method is distinguished by its mild conditions, allowing the tolerance of a wide range of functional groups and substitution patterns. The crucial step of the process involves a challenging catalytic CO2 insertion into Pd-C bonds. Copyright
- Correa, Arkaitz,Martin, Ruben
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supporting information; experimental part
p. 15974 - 15975
(2010/02/15)
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- An intramolecular charge transfer fluorescent probe: Synthesis and selective fluorescent sensing of Ag+
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An intramolecular charge transfer (ICT) fluorescent probe, in which the thiourea derivative moiety is linked to the fluorescent 4-(dimethylamino) benzamide, has been designed and synthesized. The ions-selective signaling behaviors of the probe were investigated. Upon the addition of Ag+, an overall emission enhancement of 14-fold was observed. Compound 1 displayed highly selective chelation enhanced fluorescence (CHEF) effect with Ag+ over alkali, alkali earth metal ions and some transition metal ions in aqueous methanol solutions. The prominent selective and efficient fluorescent enhancing behavior could be utilized as a new chemosensing probe for the analysis of Ag+ ion in aqueous environment.
- Mu, Honglei,Gong, Rui,Ren, Lin,Zhong, Cheng,Sun, Yimin,Fu, Enqin
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experimental part
p. 923 - 928
(2009/01/31)
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- CuCl catalyzed oxidation of aldehydes to carboxylic acids with aqueous tert-butyl hydroperoxide under mild conditions
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Oxidation of aldehydes to the corresponding carboxylic acids can be performed highly efficiently at room temperature with 70% tert-butyl hydroperoxide (in water) in the presence of a catalytic amount of easily available ligand free CuCl in acetonitrile as solvent under very mild conditions. This oxidation protocol works well for various aldehydes including aliphatic aldehydes and aliphatic dialdehydes.
- Mannam, Sreedevi,Sekar
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p. 1083 - 1086
(2008/09/18)
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- Structure-reactivity correlation in the oxidation of substituted benzaldehydes by 2,2-bipyridinium chlorochromate
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Oxidation of thirty six monosubstituted benzaldchydes by 2,2′-bipyridiniuin chlorochromate (BPCC) in diniethylsulphoxide (DMSO), leads to the formation of corresponding benzoic acids. The reaction is of first order with respect to both BPCC and aldehydes. The reaction is promoted by hydrogen ions; the hydrogen ion dependence has the form kobs= a + b[H+]. The oxidation of [2H]benzaldehyde (PhCDO) exhibited a substantial primary kinetic isotope effect. The reaction was studied in nineteen different organic solvents and the effect of solvent was analysed using Taft's and Swain's multi-parametric equations. The rates of the oxidation of para- and mete-substituted benzaldehydes showed excellent correlation in terms of Charton's triparametric LDR equation, whereas the oxidation of orfAo-substituted benzaldehydes were correlated well with tetraparametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalized effect than is the oxidation of ortho- and mem-substituted compounds, which display a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the ortho-substituents. A suitable mechanism has been proposed.
- Sharma, Pradeep K.
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experimental part
p. 1281 - 1288
(2009/12/31)
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- Carboxylation of organoboronic esters catalyzed by N-heterocyclic carbene copper(I) complexes
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Copper complexes with a CO2 fixation: Copper(I) complexes serve as excellent catalysts for the carboxylation of aryl- and alkenylboronic esters with CO2, affording a variety of functionalized carboxylic acid derivatives (see scheme). Important active intermediates such as the copper(I) aryl and carboxylate complexes, [(IPr)CuR] and [(IPr)CuOCOR] (R = 4-MeOC 6H4, IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2- ylidene), are isolated and structurally characterized. (Chemical Equation Presented).
- Ohishi, Takeshi,Nishiura, Masayoshi,Hou, Zhaomin
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supporting information; experimental part
p. 5792 - 5795
(2009/03/11)
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- Environmentally benign oxidation reaction of aldehydes to their corresponding carboxylic acids using Pd/C with NaBH4 and KOH
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Pd/C catalyst in aqueous methanol with sodium borohydride and potassium hydroxide under the air efficiently oxidized aldehydes to their corresponding carboxylic acids at room temperature. The utilization of room temperature reaction, aqueous methanol solvent, and the open-air conditions make this manipulation very interesting for economic and environmental perspectives.
- Lim, Minkyung,Yoon, Cheol Min,An, Gwangil,Rhee, Hakjune
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p. 3835 - 3839
(2008/02/07)
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- Kinetics and mechanism of the oxidation of substituted benzaldehydes by tetrabutylammonium tribromide
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The oxidation of thirty-six monosubstituted benzaldehydes by tetrabutylammonium tribromide (TBATB), in aqueous acetic acid solution, leads to the formation of the corresponding benzoic acids. The reaction is first order with respect to both TBATB and aldehydes. The reaction failed to induce the polymerization of acrylonitrile. There is no effect of tetrabutylammonium chloride ions on the reaction rate. The oxidation of [2H]benzaldehyde (PhCDO) indicated the presence of a substantial kinetic isotope effect. The effect of solvent composition indicated that the reaction rate increases with an increase in the polarity of the medium. The rates of oxidation of meta- and para-substituted benzaldehydes showed excellent correlations in terms of Charton's triparametric LDR equation whereas the oxidation of ortho-substituted benzaldehydes correlated well with tetraparametric LDS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalization effect but the oxidation of ortho- and meta-substituted compounds displayed a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction center in the rate-determining step. The reaction is subjected to steric acceleration when ortho-substituents are present.
- Chouhan,Sharma, Monica,Sharma, Vinita
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p. 582 - 587
(2008/09/21)
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- N-Alkyl-N-alkyloxycarbonylaminomethyl (NANAOCAM) prodrugs of carboxylic acid containing drugs
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Synthesis and hydrolysis in aqueous buffers of novel N-alkyl-N-alkyloxycarbonylaminomethyl (NANAOCAM) and N-aryl-N-alkyloxycarbonylaminomethyl (NArNAOCAM) derivatives of carboxylic acid containing drugs were carried out. The hydrolysis follows a SN1 type mechanism and is dependent on the nucleofugacity of the leaving group. Topical delivery of the NANAOCAM derivative of naproxen from IPM across hairless mice skin was examined in in vitro diffusion cell experiments. The prodrug was 4.5-fold less lipid soluble, 2.4-fold less water soluble and 3.6-fold less permeable than the parent drug.
- Majumdar, Susruta,Sloan, Kenneth B.
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p. 1447 - 1450
(2008/09/21)
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