- STRUCTURE AND STEREOCHEMISTRY OF GALBANIC ACID
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On the basis of the 1H NMR spectrum at 300 MHz and the results of chemical degradation, the structure of 7-coumarin has been proposed for galbanic acid.
- Bagirov, V. Yu.,Scheichenko, V. I.,Veselovskaya, N. V.,Sklyar, Yu. E.,Savina, A. A.,Kir'yanova, I. A.
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Read Online
- Ru(III) catalysed oxidation of 2-propanol by Cr(VI) in micellar media
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Acetone, the simplest ketone of abundant useful is produced from 2-propanol by oxidation with hexavalent Cr(VI) sluggishly under pseudo 1st order reaction condition. The rate is enhanced considerably using Ru(III) metal salt solution at ppm level as a cat
- Chowdhury,Rakshit,Acharjee, Animesh,Ghosh, Aniruddha,Mahali, Kalachand,Saha, Bidyut
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Read Online
- Is the tungsten(IV) complex (NEt4)2[WO(mnt)2] a functional analogue of acetylene hydratase?
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The tungsten(IV) complex (Et4N)2[W(O)(mnt)2] (1; mnt = maleonitriledithiolate) was proposed (Sarkar et al., J. Am. Chem. Soc. 1997, 119, 4315) to be a functional analogue of the active center of the enzyme acetylene hydratase from Pelobacter acetylenicus, which hydrates acetylene (ethyne; 2) to acetaldehyde (ethanal; 3). In the absence of a satisfactory mechanistic proposal for the hydration reaction, we considered the possibility of a metal-vinylidene type activation mode, as it is well established for rutheniumbased alkyne hydration catalysts with anti-Markovnikov regioselectivity. To validate the hypothesis, the regioselectivity of tungsten- catalyzed alkyne hydration of a terminal, higher alkyne had to be determined. However, complex 1 was not a competent catalyst for the hydration of 1-octyne under the conditions tested. Furthermore, we could not observe the earlier reported hydration activity of complex 1 towards acetylene. A critical assessment of, and a possible explanation for the earlier reported results are offered. The title question is answered with "no".
- Schreyer, Matthias,Hintermann, Lukas
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Read Online
- A re-examination of supra-molecular aggregation in two polymorphs of acetone 2,4-dinitro-phenyl-hydrazone
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The structure of the triclinic polymorph of acetone 2,4- dinitrophenylhydrazone, C9H10N4O4, has been redetermined from diffraction data collected at 120 (2) K; the mol-ecules are linked by C - H...O hydrogen bonds into centrosymmetric R 2 2(10)
- Wardell, James L.,Howie, R. Alan,Low, John N.,Glidewell, Christopher
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Read Online
- Aerobic oxidation of formaldehyde catalyzed by polyvanadotungstates
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Three tetra-n-butylammonium (TBA) salts of polyvanadotungstates, [n-Bu 4N]6[PW9V3O40] (PW 9V3), [n-Bu4N]5H2PW 8V4O40 (PW8V4), and [n-Bu4N]4H5PW6V6O 40·20H2O (PW6V6), have been synthesized and shown to be effective catalysts for the aerobic oxidation of formaldehyde to formic acid under ambient conditions. These complexes, characterized by elemental analysis, Fourier transform infrared spectroscopy, UV-vis spectroscopy, and thermogravimetric analysis, exhibit a catalytic activity for this reaction comparable to those of other polyoxometalates. Importantly, they are more effective in the presence of water than the metal oxide-supported Pt and/or Au nanoparticles traditionally used as catalysts for formaldehyde oxidation in the gas phase. The polyvanadotungstate-catalyzed oxidation reactions are first-order in formaldehyde, parabolic-order (slow, fast, and slow again) in catalyst, and zero-order in O2. Under optimized conditions, a turnover number of ~57 has been obtained. These catalysts can be recycled and reused without a significant loss of catalytic activity.
- Guo, Weiwei,Luo, Zhen,Lv, Hongjin,Hill, Craig L.
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Read Online
- Iron-Catalyzed Reductive Amination of Aldehydes in Isopropyl Alcohol/Water Media as Hydrogen Sources
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Reductive amination can be carried in i-PrOH/H2O as hydrogen sources using commercially available iron carbonyl complexes. Within an aqueous alkaline environment, a hydridocarboferrate is formed and its reducing potential is exploited for hydrogenation of the imine (or iminium ion) obtained in situ from aldehydes or ketones, and primary or secondary amines in almost equimolar ratio. This completely sustainable and hydrogen-free process proceeds at 100 °C using Fe3(CO)12 as catalyst precursor under convectional heating while Fe2(CO)9 gave better results when the reaction was carried out under MW dielectric heating. Both enolizable and non-enolizable aldehydes may be successfully employed in reactions with aliphatic and aromatic amines. (Figure presented.).
- Petricci, Elena,Santillo, Niccolò,Castagnolo, Daniele,Cini, Elena,Taddei, Maurizio
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supporting information
p. 2560 - 2565
(2018/07/29)
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- Burgess Reagent Facilitated Alcohol Oxidations in DMSO
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The Burgess reagent ([methoxycarbonylsulfamoyl]triethylammonium hydroxide) has historically found utility as a dehydrating agent. Herein we show that, in the presence of dimethyl sulfoxide, the Burgess reagent efficiently and rapidly facilitates the oxidation of a broad range of primary and secondary alcohols to their corresponding aldehydes and ketones in excellent yields and under mild conditions, and can be combined with other transformations (e.g., Wittig olefinations). A mechanism similar to those described for the Pfitzner-Moffatt and Swern oxidations is proposed.
- Sultane, Prakash R.,Bielawski, Christopher W.
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p. 1046 - 1052
(2018/06/18)
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- A unique annulation of 7-azaindoles with alkenyl esters to produce π-conjugated 7-azaindole derivatives
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Rhodium(iii)-catalyzed N-directed ortho C-H activation and subsequent roll-over C-H activation represents an important strategy to synthesize fused polycyclic compounds. Herein, the novel methodology broadens the scope of the coupling partner to alkenes, which working smoothly with 7-azaindoles has been proven to be an efficient and atom-economical strategy to access complex π-conjugated 7-azaindole derivatives.
- Li, Shuai-Shuai,Liu, Chen-Fei,Xia, Ying-Qi,Li, Wei-Huan,Zhang, Guo-Tai,Zhang, Xiao-Mei,Dong, Lin
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supporting information
p. 5214 - 5218
(2016/07/06)
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- IMIDAZOLINE RECEPTOR TYPE 1 LIGANDS FOR USE AS THERAPEUTICS
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This disclosure provides compounds and compositions for use as analgesics and for the treatment of various conditions, such as pain, headaches, allodynia, and fibromyalgia. The disclosure also provides compounds that are ligands, and in some embodiments, modulators (e.g., agonists), for the imidazoline receptor type 1.
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Page/Page column 265-266
(2016/07/27)
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- Cross-Dehydrogenative Coupling of Tertiary Amines and Terminal Alkynes Catalyzed by Copper Nanoparticles on Zeolite
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A wide range of catalysts based on supported copper nanoparticles have been prepared and tested in the cross-dehydrogenative coupling of tertiary amines and terminal alkynes. Copper nanoparticles on zeolite Y were found to be the most effective catalyst in the presence of tert-butyl hydroperoxide as the oxidant. Contrary to the previously reported methodologies involving copper catalysts, reactions have been accomplished without the need of an inert atmosphere and in the absence of solvent, using 1.5mol% catalyst. A variety of tertiary amines, including aromatic, benzylic and aliphatic ones, have been coupled with both aromatic and aliphatic alkynes to furnish the corresponding propargylamines in moderate-to-excellent yields. The procedure has been successfully scaled-up to 12mmol with a high conversion (93%). Moreover, the catalyst has been reused in seven cycles maintaining a good performance. Its catalytic activity has been compared with that of an array of commercial copper catalysts, being superior as regards the conversion and minimizing the alkyne homocoupling as a side reaction. The negative filtration test points to a heterogeneous nature of the process. Based on compelling experimental evidence, a novel reaction mechanism has been delineated which outlines the essential role of free radicals and the couple copper(I)/copper(II).
- Alonso, Francisco,Arroyo, Adrián,Martín-García, Iris,Moglie, Yanina
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p. 3549 - 3561
(2016/01/25)
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- Effect of CHAPS and CPC micelles on Ir(III) catalyzed Ce(IV) oxidation of aliphatic alcohols at room temperature and pressure
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Kinetics of cerium(IV) oxidation of aliphatic alcohols: ethanol, propanol, propan-2-ol, 1-butanol and 2-butanol were studied at 30 °C in the presence and absence of surfactants in acidic medium. The reaction was studied under pseudo-first-order conditions
- Ghosh, Aniruddha,Saha, Rumpa,Saha, Bidyut
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p. 223 - 237
(2014/05/06)
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- Kinetics and mechanism of oxidation of aliphatic secondary alcohols by benzyltrimethylammonium chlorobromate
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Oxidation of several secondary alcohols by benzyltrimethylammonium chlorobromate (BTMACB) in aqueous acetic acid leads to the formation of corresponding ketones. The reaction is first order with respect to BTMACB and the alcohols. The reaction failed to induce the polymerization of acrylonitrile. There is no effect of tetrabutylammonium chloride on the reaction rate. The proposed reactive oxidizing species is chlorobromate ion. The oxidation of benzhydrol-α-d (PhCDOHPh) exhibited a substantial primary kinetic isotope effect (kH/kD = 5.61 at 298 K). The effect of solvent composition indicated that the rate increases with an increase in the polarity of the solvent. The reaction is susceptible to both the polar and steric effects of the substituents. A mechanism involving transfer of a hydride ion in the ratedetermining step has been proposed.
- Sharma, Pradeep K.
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p. 2702 - 2706
(2014/06/09)
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- Kinetics and mechanism of oxidation of alcohols
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This paper describes the kinetics and mechanism of oxidation of several monohydric alcohols to the corresponding aldehydes and ketones by bis(quinuclidine)bromine(I) bromide in the presence of pyridinium trifluoroacetate. All evidence from the thermodynamic parameters, deuterium kinetic isotope effect, and Hammett reaction constants supports a two-step mechanism and suggests that the transfer of hydride ion from the substrate to the oxidant is the rate-determining step.
- Laila, Abdulhameed
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p. 307 - 312
(2013/05/23)
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- Detecting a peroxide-based explosive via molecular gelation
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A convenient and portable triacetone triperoxide (TATP) sensor was developed utilizing a thiol-to-disulfide oxidation to trigger a solution-to-gel phase transition. Using this method, TATP can be detected visually without any instrumentation.
- Chen, Jing,Wu, Weiwei,McNeil, Anne J.
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supporting information; experimental part
p. 7310 - 7312
(2012/07/31)
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- Revisiting the reaction of hydroxyl radicals with vicinal diols in water
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The carbonyl products of the reactions of hydroxyl radicals with three vicinal diols (ethane-1,2-diol, propane-1,2-diol and butane-2,3-diol) have been identified and quantified. Hydroxyl radicals were produced by γ-radiolysis of N2O-saturated aqueous solutions. The reactions result in the formation of alkoxyl radicals (~15%) followed by β-fragmentation, and α-hydroxyl alkyl radicals that undergo H2O elimination. The latter process is part of a radical chain reaction at higher diol concentrations.
- Jiang, Dong,Barata-Vallejo, Sebastian,Golding, Bernard T.,Ferreri, Carla,Chatgilialoglu, Chryssostomos
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supporting information; experimental part
p. 1102 - 1107
(2012/04/04)
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- Utility of phthalimidoacyl isothiocyanate in synthesis of quinazolines, benzoxazoles, benzimidazoles, 1,2,4-triazoles, and oxatriazepines
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Phthalimidoacyl isothiocyanates 1a,b participated in a wide range of addition-cyclization reactions. Simultaneous or subsequent cyclization of the obtained adducts gave derivatives of quinazoline, benzoxazole, benzimidazole, 1,2,4-triazole, and oxatriazepine. The structures of all the products were confirmed by microanalytical and spectroscopic data.
- Hemdan,Fahmy,Aly,Hegazi,El-Sayed
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experimental part
p. 181 - 189
(2012/02/16)
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- Synthesis of 1-aryl(hetaryl)pyrazol-5-ols and azopyrazoles on their basis
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Treatment of 3,5-dichloropyrid-2-ylhydrazine, and of mono- and dinitrophenylhydrazines with acetoacetic ester gave hydrazones and the products of their cyclization, namely pyrazolols. It was shown that acetoacetic ester 2,4-dinitrophenylhydrazone cyclizes
- Kuznetsov,Ruchkina,Kobrakov
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scheme or table
p. 441 - 447
(2012/01/19)
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- Analysis of carbonyl compounds in sea buckthorn for the evaluation of triglyceride oxidation, by enzymatic hydrolysis and derivatisation methodology
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Carbonyl compounds formed in sea buckthorn berry (Hippophae rhamnoides) and oil samples as a result of lipid oxidation were determined by enzymatic hydrolysis followed by derivatisation with 2,4-dinitrophenylhydrazine and analysed by LC-UV and electrospra
- Mathew, Sindhu,Grey, Carl,Rumpunen, Kimmo,Adlercreutz, Patrick
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experimental part
p. 1399 - 1405
(2012/02/03)
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- Preparation and antitubercular activities in vitro and in vivo of novel Schiff bases of isoniazid
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Structural modification of the frontline antitubercular isonicotinic acid hydrazide (INH) provides lipophilic adaptations (3-46) of the drug in which the hydrazine moiety of the parent compound has been chemically blocked from the deactivating process of N2-acetylation by N-arylaminoacetyl transferases. As a class, these compounds show high levels of activity against Mycobacterium tuberculosis in vitro and in tuberculosis-infected macrophages. They provide strong protection in tuberculosis-infected mice and have low toxicity. With some representatives of this class achieving early peak plasma concentrations approximately three orders of magnitude above minimum inhibitory concentration, they may serve as tools for improving our understanding of INH-based treatment modalities, particularly for those patients chronically underdosed in conventional INH therapy.
- Hearn, Michael J.,Cynamon, Michael H.,Chen, Michaeline F.,Coppins, Rebecca,Davis, Jessica,Joo-On Kang, Helen,Noble, Abigail,Tu-Sekine, Becky,Terrot, Marianne S.,Trombino, Daniella,Thai, Minh,Webster, Eleanor R.,Wilson, Rebecca
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experimental part
p. 4169 - 4178
(2009/12/04)
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- Oxidation of some unsaturated acids by tetrakis (pyridine) silver dichromate: A kinetic and mechanistic study
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The oxidation of a few unsaturated acids viz. maleic, fumaric, crotonic and cinnamic acids by tetrakis (pyridine) silver dichromate (TPSD) in dimethylsulphoxide (DMSO) leads to the formation of corresponding epoxide. The reaction is of first order with respect to TPSD and the acid. The reaction is catalysed by hydrogen ions. The hydrogen-ion dependence has the form : k obs = a + b [H+]. The oxidation of these acids was studied in nineteen different organic solvents. The solvent effect was analyzed by Kamlet's and Swain's multiparametric equations. Solvent effect indicated the importance of the cation-solvating power of the solvent. A mechanism involving a three-centre transition state has been postulated.
- Choudhary,Yajurvedi,Kumbhani,Shastri,Sharma, Vinita
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experimental part
p. 832 - 836
(2010/06/12)
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- Dowex polymer-mediated protection of carbonyl groups
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Dowex (strongly acidic cationic exchange resin) polymer is employed as solid acid catalyst for the clean and less hazardous protection of carbonyl compounds as phenylhydrazones and 2,4-dintrophenylhydrazones in ethanol under reflux conditions. The reactions proceed very smoothly and the yields of the derivatives are excellent. Copyright Taylor & Francis, Inc.
- Niknam, Khodabakhsh,Kiasat, Ali Reza,Karimi, Sadegh
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p. 2231 - 2236
(2007/10/03)
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- N-dealkylation of an N-cyclopropylamine by horseradish peroxidase. Fate of the cyclopropyl group
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Cyclopropylamines inactivate cytochrome P450 enzymes which catalyze their oxidative N-dealkylation. A key intermediate in both processes is postulated to be a highly reactive aminium cation radical formed by single electron transfer (SET) oxidation of the nitrogen center, but direct evidence for this has remained elusive. To address this deficiency and identify the fate of the cyclopropyl group lost upon N-dealkylation, we have investigated the oxidation of N-cyclopropyl-N-methylaniline (3) by horseradish peroxidase, a well-known SET enzyme. For comparison, similar studies were carried out in parallel with N-isopropyl-N-methylaniline (9) and N,N-dimethylaniline (8). Under standard peroxidatic conditions (HRP, H2O2, air), HRP oxidizes 8 completely to N-methylaniline (4) plus formaldehyde within 15-30 min, whereas 9 is oxidized more slowly (14C]-3, [1′-13C]-3, and [2′,3′-13C]-3 as substrates, radiochemical and NMR analyses of incubation mixtures revealed that the complete oxidation of 3 by HRP yields 4 (0.2 mol), β-hydroxypropionic acid (17, 0.2 mol), and N-methylquinolinium (16, 0.8 mol). In buffer purged with pure O2, the complete oxidation of 3 yields 4 (0.7 mol), 17 (0.7 mol), and 16 (0.3 mol), while under anaerobic conditions, 16 is formed quantitatively from 3. These results indicate that the aminium ion formed by SET oxidation of 3 undergoes cyclopropyl ring fragmentation exclusively to generate a distonic cation radical (14+?) which then partitions between unimolecular cyclization (leading, after further oxidation, to 16) and bimolecular reaction with dissolved oxygen (leading to 4 and 17 in a 1:1 ratio). Neither β-hydroxypropionaldehyde, acrolein, nor cyclopropanone hydrate are formed as SET metabolites of 3. The synthetic and analytical methods developed in the course of these studies should facilitate the application of cyclopropylamine-containing probes to reactions catalyzed by cytochrome P450 enzymes.
- Shaffer,Morton,Hanzlik
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p. 8502 - 8508
(2007/10/03)
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- 4-Dialkylamino-1,2-anthraquinone-1/2-arylhydrazones
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4-Dialkylamino-1,2-anthraquinones 3 condense in hydrochloric DMSO with arylhydrazines 4 to give the red 4-dialkylamino-1,2-anthraquinone-1- arylhydrazones 5 and the blue 4-dialkylamino-1,2-anthraquinone-2- arylhydrazones 6. The colours of these are discussed with regard to the similar coloured 4-dialkylamino-1,2-naphthoquinone- 1/2 -arylhydrazones.
- Kallmayer,Bock
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p. 166 - 170
(2007/10/03)
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- Reactions of regioisomeric fluoroalkyl-containing β-aminovinyl ketones with hydrazines
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Fluoroalkyl β-alkyl-β-aminovinyl ketones react with hydrazine hydrate to give the respective pyrazoles, and with phenylhydrazine they form a mixture of pyrazoles and 5-hydroxy-Δ2-pyrazolines. Alkyl(aryl) β-fluoroalkyl-β-aminovinylketones do not react with the hydrazines mentioned above. With 2,4-dinitrophenylhydrazine, both types of fluoroalkyl-containing β-aminovinyl ketones give only hydrazones of the corresponding methyl alkyl(aryl) ketones.
- Pashkevich,Filyakova,Kuznetsova
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p. 2868 - 2870
(2007/10/03)
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- Oxidative behaviours and relative reactivities of some α-hydroxy acids towards bromate ion in hydrochloric acid medium
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The oxidation kinetics of some α-hydroxy acids by potassium bromate in dilute hydrochloric acid medium have been studied. The reactions are first order with respect to bromate ion. α-hydroxy acid and hydrogen ion concentrations. The reaction rate is governed by two factors : (i) the ease with which the protonated hydroxy acid is produced and (ii) the stability of the intermediate (1:1) bromate ester. The activation parameters of the reactions have been compared. The plausible mechanism of the oxidation process has been suggested. The reactivity of the α-hydroxy acids towards bromate ion are as follows: 9-hydroxy-9-carboxy fluorene> atrolactic acid> mandelic acid> benzilic acid> α-hydroxyisobutyric acid> lactic acid> glycolic acid.
- Gupta, Kalyan Kali Sen,Banerjee, Amalendu,Chatterjee, Hrishikesh
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p. 5323 - 5330
(2007/10/02)
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- Generation of hydroxyl radicals from 1-hydroxypyridine-2(1H)-thione and their application to organic synthesis
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Upon irradiation with visible light N-hydroxypyridine-2-thione 1 gives rise to hydroxyl radicals which can be used in radical chain reactions involving selective hydrogen abstraction as the key-step. Key Words: N-hydroxypyridine-2-thione / hydroxyl radicals
- Boivin, J.,Crepon, E.,Zard, S. Z.
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p. 145 - 150
(2007/10/02)
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- Septanose Carbohydrates. III Oxidation-Reduction Products from 1,2:3,4-Di-O-isopropylidene-α-D-gluco-septanose: Preparation of L-Idose Derivatives
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Oxidation of 1,2:3,4-di-O-isopropylidene-α-D-glucoseptanose (1a) with dimethyl sulfoxide and acetic anhydride has yielded methylthiomethyl ether (1b), ketone (2), and a novel product (3).Reduction of (2) gave (1a) and its L-ido isomer (4a) which yielded t
- Driver, Graham E.,Stevens, John D.
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p. 2063 - 2081
(2007/10/02)
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- Microbial Transformation of α-Santonin by Pseudomonas cichorii S: Identification of Products
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4α, 5α-Dihydroxysantonin (4) and ethyl 3-oxoeudesma-4, 6-diene-12-oate (2, 4-DNP derivative 3) have been characterised as microbial transformation products of α-santonin (1) by Pseudomonas cichorii S.The assigned structures have been confirmed by their pa
- Naik, U. P.,Mavinkurve, S.,Naik, U. S.,Paknikar, S. K.
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p. 381 - 382
(2007/10/02)
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- Functionalisation of Saturated Hydrocarbons. Part IX. Oxidation of Cedrol, β- and γ-Eudesmol, Sclareol, Manoyl Oxide, 1,9-Dideoxyforskolin, Methyl trans-Dihydrojasmonate, and Tetrahydrolinalool by the 'Gif System'
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The oxidation of cedrol (1), β- and γ-eudesmol (6 and 7, resp.), sclareol (14), manoyl oxide (15), 1,9-dideoxyforskolin (22) (+/-)-methyl trans-dihydrojasmonate (28), and tetrahydrolinalool (32), nearly all of natural terpenoid origin, by the 'Gif system' has afforded a number of novel products (3, 11, and 12, 16/17, 18/19, 26, 29-31, and ketones corresponding to 34-35, resp.).The structures of these compounds were established by spectroscopic techniques including 2D-NMR and, where appropriate, by comparison with authentic samples.
- Barton, Derek H. R.,Beloeil, Jean-Claude,Billion, Annick,Boivin, Jean,Lallemand, Jean-Yves,et al.
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p. 2187 - 2200
(2007/10/02)
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- The Synthesis of Ketones via α-Silyl Sulphides
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α-Phenylthiosilanes (2) have been prepared by alkylation of the anion (4) derived from the 1-phenylthio-1-trimethylsilylalkane (1).These anions (4) have benn prepared by a variety of methods including, direct deprotonation of (1), displacement of a phenylthio group by lithium naphthalenide addition of an alkyl-lithium to 1-phenylthio-1-trimethylsilylethene (7), and transmetallation of a tributylstannyl moiety.The formation of an alkyl-lithium by reaction of lithium naphthalenide with a phenyl sulphide provided an additional route to (2) from bis(phenylthio)acetals (8).An alternative path to the α-phenylthiosilanes (2) was to reduce the corresponding α-phenylsulphonylsilane (15); these, in turn, being readily available from alkylation or silylation of α-sulphonyl anions.The α-phenylthiosilanes (2) were converted into the O-trimethylsilylphenylthioacetal (18) by the sila-Pummerer rearrangement, although this was complicated by vinyl sulphide (20) formation in certain cases.Subsequent hydrolysis of (18) and (20) gave the ketone (3).
- Ager, David J.
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p. 195 - 204
(2007/10/02)
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- SYNTHESIS OF DIISOPROPYLIDENETHIIRANE (THIIRANORADIALENE) AND ITS REACTIONS
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The first stable 2,3-methylenethiirane, 2,3-diisopropylidenethiirane 6, was prepared by pyrolysis of lithium salt of tosylhydrazone of 2,2-dimethyl-4-isopropylidene-3-thietanone.The desulfurization of 6 by phosphines and carbenes gave 2,5-dimethyl-2,3,4-h
- Ando, Wataru,Hanyu, Yukio,Kumamoto, Yorio,Takata, Toshikazu
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p. 1989 - 1994
(2007/10/02)
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- Kinetics and Mechanism of Oxidation of Alcohols by Ceric Ammonium Nitrate
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The main product of the oxidation of secondary alcohol by ceric ammonium nitrate is the corresponding ketone.The reaction is of first-order with respect to the oxidant but exhibit a Michaelis-Menten type kinetics with respect to the alcohol.The formation constants of the alcohol-CeIV complex and its thermodynamic parameters have been calculated.The rate of decomposition of the complex and the activation parameters have also been evaluated.The rates of decomposition of the complex correlate with Taft's ?* values with a low negative reaction constant.The oxidation induced polymerisation of acrylonitrile.The retardation of rate with increasing acidity has been explained on the formation of kinetically inactive protonated alcohol.The protonated constants for the various alcohol have been calculated.The presence of a small primary kinetic isotope effect, kH/kD = 2.3, confirms that the rate-determining step involves a C-H bond rupture in a non-symmetrical transition state.
- Mathur, Dwarka, L.,Agarwal, Anupma,Banerji, Kalyan K.
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p. 519 - 522
(2007/10/02)
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- RING CLEVEAGE REACTIONS OF SUBSTITUTED 2-ISOXAZOLINES BY PENTACARBONYLIRON UNDER ULTRAVIOLET IRRADIATION
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The photoirradiation of 3,5-disubstituted 2-isoxazolines and Fe(CO)5 in MeOH causes the N-O and C4-C5 bond cleveage to give two fragments of aldehydes and ketones, while that of 2-isoxazolines having no substituent at 5-position gives additional β-hydroxy- and β-methoxyketones.
- Nitta, Makoto,Kobayashi, Tomoshige
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- Hydrogen Peroxide Oxidation of α-(N,N-Dialkyl)aminoketones
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α-(N,N-Dialkyl)aminoketones are fragmented oxidatively by hydrogen peroxide, leading to carboxylic acids and products derived from iminium intermediates.
- Wenkert, David,Eliasson, K. Margareta,Rudisill, Duane
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p. 392 - 393
(2007/10/02)
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- KINETICS OF THE FORMATION OF 2,4-DINITROPHENYLHYDRAZONES IN HYDROCARBONS
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The kinetics of the formation of 2,4-dinitrophenylhydrazones in a hydrocarbon medium were studied.By an integral method it was found that the reaction of carbonyl compounds with 2,4-dinitrophenylhydrazine is reversible, and the forward and reverse reactio
- Kuznetsova, E. V.,Mil'kina, T. N.,Morzhakova, T. M.,Taranenko, S. A.,Kudinova, L. M.,Batalin, O. E.
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p. 1914 - 1918
(2007/10/02)
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- Synthesis, spectral and structural studies, and an evaluation of the hydrogen bonding of some phenylhydrazones
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A series of 46 phenylhydrazones, some novel, containing a variety of structural types has been synthesised. These have been studied by 1H n.m.r. and i.r. spectroscopy with respect to potential inter- and intra-molecular hydrogen bonding. ortho-Nitro or -carbonyl groups form strong hydrogen bonds to the imino-group which are readily observed by 1H n.m.r. but not by i.r. spectroscopy. 'Terminal' carbonyl groups also form strong hydrogen bonds to the imino-group and these can be detected by both i.r. and 1H n.m.r. spectroscopy. When both ortho-nitro- or -carbonyl groups and 'terminal' carbonyl groups are present the imino hydrogen atom is doubly hydrogen bonded and this is apparent in the 1H n.m.r. spectrum. The formation of an intramolecular hydrogen bond in the phenylhydrazone prevents the formation of an intermolecular hydrogen bond between the phenylhydrazone and a polar solvent.
- Kaberia, Festus,Vickery, Brian,Willey, Gerald R.,Drew, Michael G. B.
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p. 1622 - 1626
(2007/10/02)
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