- 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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Read Online
- 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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- 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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- 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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- Defluorination of 4-fluorothreonine by threonine deaminase
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4-Fluorothreonine (4-FT) is the only naturally occurring fluorinated amino acid antibiotic. Although two conserved proteins in the 4-FT pathway have been found to be involved in self-detoxification mechanisms, the 4-FT-producing strains may also require an alternative pathway to degrade the intracellular 4-FT. In this study, we examined the possible degradation role of three enzymes involved in threonine metabolite pathways toward 4-FT as a possible degradation route to avoid in vivo 4-FT accumulation. Among these three enzymes, threonine deaminase was found to catalyse a defluorination reaction to generate 4-hydroxy-α-ketobutyrate, which is supposed to be further metabolised by an aldolase that likely is a unique occurrence in the 4-FT-producing strains. Our finding may constitute a 4-FT degradation pathway as a complementary resistance mechanism.
- Deng, Hai,Wu, Linrui
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supporting information
p. 6236 - 6240
(2020/09/07)
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- Synthesis of N-Sulfonylformamidines by tert-butyl Hydroperoxide–Promoted, metal-free, direct oxidative dehydrogenation of aliphatic amines
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A direct and convenient metal-free method to prepare sulfonyl amidines in the presence of aqueous tert-butyl hydroperoxide (T-HYDRO) has been developed. Different tertiary and secondary amines were tested for compatibility with the oxidative conditions and could be coupled with sulfonyl azides to form the corresponding amidines in moderate to good yields.
- Rouzi, Ayijiamali,Hudabaierdi, Ruzeahong,Wusiman, Abudureheman
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supporting information
p. 2475 - 2481
(2018/04/14)
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- Kinetics and mechanism of oxidation of glycine and alanine by Oxone? catalyzed by bromide ion
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Oxidation of glycine and alanine by Oxone? catalysed by bromide ions has been studied in acidic medium. The reaction is initiated by the oxidation of bromide to bromine, which then reacts with the amino acid. The formation of bromine is supported by the spectrophotometric examination of the reaction mixture. The proposed intermediate involves a complex formation between bromine and the anion of the amino acid. The rate of the reaction is inhibited by an increase in the hydrogen ion concentration due to the protonation equilibria of the amino acids. A mechanism is proposed and the derived rate law was verified graphically. Effect of relative permittivity, ionic strength and temperature was also carried out and these effects are also in support of the mechanism proposed.
- Thombare, Malharrao R.,Gokavi, Gavisiddappa S.
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p. 1545 - 1551
(2015/02/18)
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- Oxidized single-walled carbon nanotubes (swcns-cooh) as a new catalyst for the protection of carbonyl groups as hydrazones
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Nano-materials are considered as suitable heterogeneous catalysts for many organic reactions. Herein oxidized carbon nanotube (SWCNTs-COOH) has been reported as a heterogeneous catalyst, for protection of carbonyl groups as hydrazones in EtOH at 80 C. The reactions proceed smoothly with good to excellent yields, and the SWCNTs-COOH used can be recycled.
- Borazjani, Maryam Kiani,Safaei, Hamid Reza,Panahandeh, Majid,Kiani, Ali Reza,Kiani, Masoumeh,Mofarahi, Masoud
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p. 279 - 281
(2013/12/04)
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- Selective reduction of carboxylic acids to aldehydes through manganese catalysed hydrosilylation
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The direct reduction of carboxylic acids to disilylacetals was achieved through a manganese catalyzed hydrosilylation reaction in the presence of triethylsilane under mild conditions, at r.t. and under UV irradiation (350 nm). The aldehydes were obtained in good to excellent yields after acidic hydrolysis.
- Zheng, Jianxia,Chevance, Soizic,Darcel, Christophe,Sortais, Jean-Baptiste
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supporting information
p. 10010 - 10012
(2013/10/22)
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- Selective reduction of esters to aldehydes under the catalysis of well-defined NHC-iron complexes
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On a direct course to the aldehyde: Hydrosilylation catalyzed by a well-defined N-heterocyclic-carbene-iron complex under UV irradiation enabled the selective reduction of esters to aldehydes (see scheme; Bn=benzyl, Mes=mesityl). The low catalyst loading and very mild reaction conditions make this chemoselective transformation a promising alternative to the reduction of esters with diisobutylaluminum hydride. Copyright
- Li, Haoquan,Misal Castro, Luis C.,Zheng, Jianxia,Roisnel, Thierry,Dorcet, Vincent,Sortais, Jean-Baptiste,Darcel, Christophe
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supporting information
p. 8045 - 8049
(2013/08/23)
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- Kinetics and mechanism of the oxidation of aliphatic primary alcohols by imidazolium fluorochromate
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The oxidation of nine aliphatic primary alcohols by imidazolium fluorochromate (IFC) in dimethylsulphoxide leads to the formation of corresponding aldehydes. The reaction is first order with respect to IFC. A Michaelis-Menten type kinetics is observed with respect to alcohols. The reaction is promoted by hydrogen ions; the hydrogen-ion dependence has the form : kobs = a + b [H+]. The oxidation of [1,1- 2H2]ethanol (MeCD2OH) exhibits a substantial primary kinetic isotope effect (kH/kD = 5.87 at 298 K). The reaction has been studied in nineteen different organic solvents. The solvent effect was analysed using Taft's and Swain's multiparametric equations. The rate of oxidation is susceptible to both polar and steric effects of the substituents. A suitable mechanism has been proposed.
- Gehlot,Gilla,Mishra,Sharma, Vinita
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experimental part
p. 685 - 692
(2012/04/04)
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- One-pot oxidation of alanine and its ethyl ester with a mild oxidant 4′-methylazobenzene-2-sulfenyl bromide
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One-pot oxidation of alanine and its ethyl ester with a mild oxidant 4′-methylazobenzene-2-sulfenyl bromide is described. Using a nonreactively water-soluble electrophilic species, 4′-methylazobenzene-2-sulfenyl bromide, with L-alanine and its ethyl ester (in 3:1 molar proportions) in aqueous solution at room temperature, the corresponding sulfenimines are prepared. On hydrolysis in acidic medium at room temperature, these sulfenimines give ethanal and pyruvic acid respectively. Taylor & Francis Group, LLC.
- Barman, Pranjit,Bhattacharjee, Saibal Kanti,Bhattacharjee, Tirtha
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experimental part
p. 2870 - 2875
(2011/08/22)
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- Oxidation of aliphatic primary alcohols by morpholinium chlorochromate: A kinetic and mechanistic approach
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The oxidation of nine aliphatic primary alcohols by morpholinium chlorochromate (MCC) in dimethylsulfoxide leads to the transformation of alcohols to the corresponding aldehydes. The reaction is first order with respect to both MCC and the alcohol both. The reaction is catalysed by hydrogen ions. The hydrogen-ion dependence has the form: kobs = a + A[H +]. The oxidation of [1,1-2H2]ethanol (MeCD2OH) exhibits a substantial primary kinetic isotope effect. The reaction has been studied in nineteen different organic solvents. The solvent effect was analysed using Taft's and Swain's multiparametric equations. The rate of oxidation is susceptible to both polar and steric effects of the substituents. A suitable mechanism has been proposed.
- Choudhary,Yajurvedi,Soni,Agarwa,Sharma, Vinita
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experimental part
p. 1061 - 1066
(2011/05/05)
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- CuCI/CCI4-Promoted Convenient Synthesis of Sulfonyl Amidines from Tertiary Amines and Sulfonyl Azides
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Chemical Equation Presentation Promoted by CuCI/CCI4, a variety of sulfonyl azides and tertiary amines were successfully coupled to give sulfonyl amidine derivatives in good to excellent yields. A possible mechanism for this reaction Is discussed
- Xu, Xiaoliang,Ge, Zhichuang,Cheng, Dongping,Lei, Ma.,Lu, Chunshan,Zhang, Qunfeng,Yao, Nan,Li, Xiaonian
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supporting information; experimental part
p. 897 - 899
(2010/06/13)
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- Nitration of fullerene derivatives under mild conditions
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A new family of N-(2,4-dinitrophenyl)-2-pyrazolino[60]fullerene derivatives has been synthesized by electrophilic nitration using nitronium triflate. As evidenced by CV and OSWV experiments, these species show enhanced electron-accepting properties (up to
- Oswald, Frederic,De La Cruz, Pilar,Langa, Fernando
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p. 1051 - 1054
(2008/02/13)
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- 5-Methyl-2-furylglyoxal, 5-methyl-4-nitro-2-furylglyoxal, and their derivatives. Nitration of 2-(5-methyl-2-furyl)quinoxaline
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The oxidation of 2-acetyl-5-methyl-4-R-furans (R = H, NO2) by selenious acid was studied. Derivatives substituted at the C=O groups of the corresponding glyoxals were obtained. The nitration of 2-(5-methyl-2-firyl)quinoxaline was carried out at C(4). Oxidative splitting of the β-nitrofuryl group occurs at the C(4)-C(5) and C(5)-O bonds.
- Saldabol,Popelis,Slavinska
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p. 783 - 788
(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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- AUTOOXIDATION OF ACETYLENES AND THEIR DERIVATIVES. XXV. 1-PHENYL-4-PENTEN-1-YN-3-0L AND 1-PHENYL-4-HEXEN-1-YN-3-OL
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During the autooxidation of secondary enynyl alcohols attack by oxygen takes place at the C-H bonds at the α position to the triple and double bonds and the hydroxyl group.The initially formed unstable hydroxyhydroperoxides dissociate under the oxidation conditions into the corresponding enynyl ketones, acetylenic keto epoxydes, and products from degradation of the carbon skeleton.
- Stepin, S. G.,Tishchenko, I. G.
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p. 1771 - 1774
(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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- Determination of Nanogram Amounts of Carbonyls as 2,4-Dinitrophenylhydrazones by High-Performance Liguid Chromatography
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A simple method has been developed for the separation and quantitation of nanogram amounts of carbonyl compounds including aliphatic, unsaturated, and aromatic carbonyls as well as dicarbonyls and other difunctional carbonyls.This method entails the separ
- Fung, Kochy,Grosjean, Daniel
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p. 168 - 171
(2007/10/02)
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