- The reactions of atomic chlorine with acrolein, methacrolein and methyl vinyl ketone
-
The rate constants and the products of the reactions between atomic chlorine and acrolein, methachlorine, and methyl vinyl ketone were determined. Rate coefficients for the reactions of chlorine with acrolein and with methyl vinyl ketone were slightly dependent at 1.6 and 760 torr, although the rate coefficients at 1.6 torr were a factor of only ~ 2 smaller than the values obtained at 1 atm. The reaction between Cl atoms and methacrolein in synthetic air and 1 atm yielded chloroacetone, formaldehyde, CO, and HCl. Between Cl atoms and acrolein, the products of reaction were HCl, chloroacetaldehyde, formaldehyde, and CO. For the reaction between Cl atoms and methyl vinyl ketone, the products were chloroacetaldehyde, formaldehyde, and CO. Branching ratios for abstraction (the fraction of reactions occurring by abstraction relative to the sum of addition and abstraction processes) were 0.22 for acrolein, 0.18 for methacrolein, and 0.03 for methyl vinyl ketone. Vast quantities of isoprene were converted to methacrolein in the atmosphere, and several channels of oxidation following attack by chlorine on methacrolein led to CO formation, with an overall yield of ~ 0.75.
- Wayne,Canosa-Mas,Cotter,Duffy,Thompson
-
-
Read Online
- Oxidation mechanisms for ethyl chloride and ethyl bromide under atmospheric conditions
-
Partially chlorinated and/or brominated alkanes are present in the earth's atmosphere as the result of natural and anthropogenic activities, and their oxidation mechanisms under atmospheric conditions have been the subject of a number of recent studies. The Cl-atom initiated oxidation of ethyl chloride and ethyl bromide was studied as a function of temperature (220-298 K) in an environmental chamber equipped with an FTIR spectrometer. Products resulting from abstraction at the -CH2Cl group included CH3C(O)Cl, CO2, CH3C(O)OOH, CH3C(O)OH, CH2O, CO, HCOOH, and CH3OH. The HCl-elimination reaction possessed an energy barrier of about 6 kcal/mole. As a result of this modest barrier, chemical activation played an important role in the chemistry of internally excited CH3CHClO radicals generated from the exothermic reaction of the CH3CHClO2 radical with NO. BrCH2CH2 radicals, generated via Cl-atom abstraction at the -CH3 group, reacted via Br-atom elimination to form ethylene or via addition of O2 to form a peroxy radical. The generation of an alkene is likely to be general a occurrence in the tropospheric chemistry of alkyl bromides.
- Orlando,Tyndall
-
-
Read Online
- Photooxidation of exhaust pollutants: III. Photooxidation of the chloroethenes: Degradation efficiencies, quantum yields and products
-
The photochemical decomposition and oxidation of the chloroethenes C2H4-XClX (x=1-4) was investigated in the gas phase by irradiation with a low pressure mercury lamp in an oxygen atmosphere. Degradation efficiencies directly depend on the number of chlorine atoms both at 185 and 254 nm. The quantum yields for degradation increase from 2-3 for vinyl chloride to > 100 for tri- and tetrachloroethene at 185 nm in the 10-3 bar concentration range. At 254 nm we measured nearly time independent quantum yields of around 10 for tri- and 40 for tetrachloroethene. The photooxidation products and their mechanism of formation are discussed in detail.
- Guertler,Moeller,Sommer,Mueller,Kleinermanns
-
-
Read Online
- Atmospheric chemistry and environmental assessment of inhalational fluroxene
-
Smog chamber/gas chromatography techniques are used to investigate the atmospheric degradation of fluroxene, an anesthetic, through oxidation with OH and Cl radicals at 298 K and under atmospheric pressure of N2 or air. The measured rate consta
- Bravo, Ivan,Rodriguez, Ana,Rodriguez, Diana,Diaz-De-Mera, Yolanda,Notario, Alberto,Aranda, Alfonso
-
-
Read Online
- One-pot Preparation of 2-Chloromethyldioxolanes and 2-Aminothiazoles from Chloromethyltrioxanes
-
Thermal degradation of chloromethyltrioxanes in the presence of catalytic amount of montmorillonite clay generated α-chloroaldehydes with high purity, which were treated in situ with ethylene glycol or thiourea to afford 2-chloromethyldioxolanes and 2-aminothiazoles, respectively.The clay catalysts used were removed by filtration.
- Wakasugi, Takashi,Miyakawa, Tadashi,Suzuki, Fukuichi,Itsuno, Shinichi,Ito, Koichi
-
-
Read Online
- Kinetics and mechanism of the oxidative regeneration of carbonyl compounds from oximes by pyridinium bromochromate
-
The oxidative deoximination of several aldo- and keto-oximes by pyridinium bromochromate (PBC), in dimethylsulfoxide, exhibited a first-order dependence on both the reductant (oxime) and the oxidant (PBC). The oxidation of ketoximes is slower than that of aldoximes. The rates of oxidation of aldoximes correlated well in terms of the Pavelich-Taft dual substituent-parameter equation. The low positive value of polar reaction constant indicated a nucleophilic attack by a chromate-oxygen on the carbon. The reaction is subject to steric hindrance by the alkyl groups. The reaction of acetaldoxime has been studied in 19 different organic solvents. The solvent effect has been analyzed by Taft's and Swain's multiparametric equations. A mechanism involving the formation of a cyclic intermediate, in the rate-determining step, has been proposed.
- Sharma, Pradeep K.
-
-
Read Online
- Oxidative regeneration of carbonyl compounds from oximes by pyridinium fluorochromate: A kinetic and mechanistic study
-
The oxidative deoximination of several aldoximes and ketoximes by pyridinium fluorochromate, in dimethyl sulphoxide, exhibited a first order dependence on pyridinium fluorochromate. A Michaelis-Menten type kinetics was observed with respect to oximes. The oxidation of ketoximes is slower than that of aldoximes. The rates of oxidation of aldoximes correlated well in terms of Pavelich-Taft dual substituentparameter equation. The low positive value of polar reaction constant indicated a nucleophilic attack by a chromate-oxygen on the carbon. The reaction is subjected to steric hindrance by the alkyl groups. The reaction of acetaldoxime has been studied in 19 different organic solvents. The solvent effect has been analyzed by multiparametric equations. A mechanism involving the formation of a cyclic intermediate, in the rate-determining step is suggested.
- Sharma, Ajay,Vyas, Neha,Choudhary,Prasadrao, Ptsrk,Sharma, Vinita
-
-
Read Online
- Preparation of Chloroacetaldehyde Cyclic Trimer and Its Depolymerization
-
Chlorination of paraldehyde gave chloroacetaldehydes which were treated with concd sulfuric acid to afford cyclic trimer (3) of chloroacetaldehyde (CA).Depolymerization of 3 yielded pure CA satisfactory.
- Wakasugi, Takashi,Tonouchi, Naka,Miyakawa, Tadashi,Ishizuka, Makoto,Yamauchi, Takashi,et al.
-
-
Read Online
- Synthesis, characterisation and theoretical calculations of 2,6-diaminopurine etheno derivatives
-
Four derivatives of 2,6-diaminopurine (1) were synthesised and characterised. When 1 was reacted with chloroacetaldehyde, 5-aminoimidazo[2,1-i] purine (2), 9-aminoimidazo[2,1-b]purine (3), 9-aminoimidazo[1,2-a]purine (4) and diimidazo[2,1-&:2′,1′-i]purine (5) were formed. The purified products (3-5) were fully characterised by MS, complete NMR assignments as well as fluorescence and UV spectroscopy. The purified, isolated yields of these products (3-5) varied from 2.5 to 30%. The relative stability of different tautomers was investigated by theoretical calculations. Fluorescence characteristics are also discussed and compared to the starting material 1 and a reference molecule 2-aminopurine. The Royal Society of Chemistry 2005.
- Virta, Piritta,Koch, Andreas,Roslund, Mattias U.,Mattjus, Peter,Kleinpeter, Erich,Kronberg, Leif,Sjoeholm, Rainer,Klika, Karel D.
-
-
Read Online
- New nucleoside analogs from 2-amino-9-(β-d-ribofuranosyl)purine
-
Four novel derivatives of 2-amino-9-(β-D-ribofuranosyl)purine (1) were synthesised and fully characterised. When 1 was reacted with chloroacetaldehyde (a), 2-chloropropanal (b), bromomalonaldehyde (c) and a mixture of chloroacetaldehyde + malonaldehyde (d), 3-(β-D-ribofuranosyl)-imidazo-[1, 2a]purine (2), 3-(β-D-ribofuranosyl)-5-methylimidazo-[1,2a]purine (3), 3-(β-D-ribofuranosyl)-5-formylimidazo-[1,2a]purine (4) and 9-(β-D-ribofuranosyl) 2-(3,5-diformyl-4-methyl-1,4-dihydro-1-pyridyl)purine (5) were formed, respectively. The products were isolated, purified by chromatography and characterised by MS, complete NMR assignment as well as fluorescence and UV spectroscopy. The yields of these reactions were moderate (14-20%). The fluorescence properties differed from those of the starting compound and the quantum yields were considerably lower.
- Virta, Piritta,Holmstroem, Toni,Roslund, Mattias U.,Mattjus, Peter,Kronberg, Leif,Sjoeholm, Rainer
-
-
Read Online
- Nucleophilic Substitution Reactions at Chloro-Substituted Ozonides and at a Chlorinated Dimeric Peroxide
-
Reactions of substituted 3-chloro- (2a-4a) and 3,5-dichloro-1,2,4-trioxolanes (9a, 10a) with AgBF4 in the presence of LiF gave the corresponding fluoro-substituted ozonides (2b - 4b and 9b and 10b).Substitutions of some of these chlorinated ozonides by the methoxy and by the acetoxy groups, and of 3,6-dichloro-3,6-dimethyl-1,2,4,5-tetroxane (22a) with the acetoxy group have been achieved too.
- Griesbaum, Karl,Schlindwein, Konrad
-
-
Read Online
- A New One-Pot Fluorescence Derivatization Strategy for Highly Sensitive MicroRNA Analysis
-
MicroRNAs (miRNAs) modulate the expression of over 30 % of mammalian genes during development and apoptosis, and abnormal expression of miRNAs may lead to a range of human pathologies. Therefore, analysis of miRNAs is valuable for disease diagnostics. In this work, a novel one-pot fluorescence derivatization strategy was developed for miRNA analysis. The mechanism of the derivatization reaction was explored by using instrumental methods, including liquid chromatography, fluorescence spectroscopy, and mass spectrometry. Highly fluorescent N6-ethenoadenine (?-adenine) was formed and detached from the miRNA sequence through the reaction of adenine in nucleic acids with 2-chloroacetaldehyde (CAA) at 100 °C. This is the first experimental evidence that the cooperation of formed ?-adenine and water-mediated hydrogen-bond interaction between the proton at the 2′- and the oxyanion at 3′-positions stabilized the oxocarbenium significantly, which makes the depurination and derivatization of miRNA highly effective. Based on this derivatization strategy, a facile and sensitive high-performance liquid chromatography method was developed for quantitative assay of miRNAs. In combination with magnetic solid-phase extraction (MSPE), the HPLC method was shown to be useful for the determination of microRNAs at sub-picomolar level in serum samples.
- Pan, Li,Zhang, Huaisheng,Zhao, Jingjin,Ogungbe, Ifedayo Victor,Zhao, Shulin,Liu, Yi-Ming
-
-
Read Online
- On five- vs six-membered diacetal formation from threitol and the intermediacy of unusually stable protonated species
-
The long known, but hitherto poorly understood, thermodynamically controlled diacetalation of rac-threitol with alkylaldehydes provided bicyclic, cis-tetraoxadecalin (TOD) ('66') and bi(dioxolanyl) (BDO) ('55') products, shown to be formed in acid-concentration and temperature-dependent ratio. The configurational and conformational isomeric diacetals obtained in four such reactions of substituted aldehydes (RCHO, R = CH3, CH2Cl, CH2Br, CO2CH3) with rac-threitol were isolated and characterized. A variable acid- concentration analysis of the equilibrium mixture of products in one such case (R = CH2Br) was performed and provided equilibrium constants and, hence, free-energy differences among these products and their relatively stable protonated intermediates. The latter were rationalized by the unusually high proton-affinity calculated for the cis-TOD ('66') form.
- Grabarnik, Mikhail,Lemcoff, N. Gabriel,Madar, Ravit,Abramson, Sarah,Weinman, Sarah,Fuchs, Benzion
-
-
Read Online
- Selective reduction with lithium bis- Or tris(dialkylamino)aluminum hydrides. III. Reduction of primary carboxamides to aldehydes by lithium tris(diethylamino)aluminum hydride
-
Both aliphatic and aromatic primary carboxamides are reduced readily to the corresponding aldehydes by lithium tris(diethylamino)aluminum hydride in THF at room temperature in yields of 50-90%.
- Cha, Jin Soon,Lee, Jae Cheol,Lee, Heung Soo,Lee, Sung Eun,Kim, Jong Mi,Kwon, Oh Oun,Min, Soo Jin
-
-
Read Online
- Kinetics and correlation analysis of reactivity in the oxidation of aliphatic primary alcohols by isoquinolinium dichromate in non-aqueous medium
-
Mild oxidation in dimethyl sulfoxide (DMSO) medium by isoquinolinium dichromate (IQDC) of aliphatic primary alcohols produces corresponding carbonyl compounds. A Michaelis-Menten kind kinetics noticed as for alcohols while unit dependency on rate observed as for IQDC. At non-identical temperatures the formation constants and the rates of decomposition of alcohol-IQDC complexes have been evaluated. Thermodynamic parameters and activation parameters for formation of the complex and break down of the complexes have been determined respectively. The oxidation process accelerates with increase in proton concentration. An α-C-H bond fisson in the rate-controlling step suggested by the deuterium isotope effect. For oxidation of ethanol, kH/kD = 5.82 at 293 K, was observed. The oxidation rates have been evaluated in 19 organic solvents and greater role of solvating power of the cation is observed. Depended on the kinetic parameters, solvent effect analysis and the outcome of thermodynamic parameters, a mechanism in which rate-controlling break down of the complex is suggested, to give the resulting product through hydride-ion transfer with a cyclic transition state.
- Kalal, Reena,Panday, Dinesh
-
-
- Continuous preparation method for 2-aminopyrrolyl-3-ethyl carboxylate
-
The invention provides a continuous preparation method for 2-aminopyrrolyl-3-ethyl carboxylate. The preparation method comprises the steps: continuously feeding a trichloroacetaldehyde solution to a first continuous reactor to carry out continuous acid catalyzed depolymerization on trichloroacetaldehyde, so as to a chloroacetaldehyde solution; and continuously feeding a 3-amino-3-imidoethyl propionate solution, an alkali solution and the chloroacetaldehyde solution to a second continuous reactor for a condensation reaction, thereby obtaining the 2-aminopyrrolyl-3-ethyl carboxylate. According to the continuous process, the restriction to anhydrous chloroacetaldehyde is broken through, the anhydrous chloroacetaldehyde is prepared by a continuous reaction, the reaction speed is higher than that of batches, and the yield is higher; and when the prepared chloroacetaldehyde solution is directly applied to the condensation reaction of next step, the material proportioning ratio is more controllable, the front and rear two steps can be compatible, and thus, the yield of the 2-aminopyrrolyl-3-ethyl carboxylate is globally increased. In addition, due to the continuous process, a scaling effect of the batches is avoided, and high yield during industrial application is also guaranteed.
- -
-
Paragraph 0039-0041; 0048-0050; 0057-0059; 0066-0068; 0075
(2020/01/12)
-
- Carbene-Catalyzed α-Carbon Amination of Chloroaldehydes for Enantioselective Access to Dihydroquinoxaline Derivatives
-
An NHC-catalyzed α-carbon amination of chloroaldehydes was developed. Cyclohexadiene-1,2-diimines are used as amination reagents and four-atom synthons. Our reaction affords optically enriched dihydroquinoxalines that are core structures in natural products and synthetic bioactive molecules.
- Huang, Ruoyan,Chen, Xingkuan,Mou, Chengli,Luo, Guoyong,Li, Yongjia,Li, Xiangyang,Xue, Wei,Jin, Zhichao,Chi, Yonggui Robin
-
supporting information
p. 4340 - 4344
(2019/06/14)
-
- Rearrangement Reaction Based on the Structure of N-Fluoro- N-alkyl Benzenesulfonamide
-
A novel rearrangement reaction based on the structure of N-fluoro-N-alkyl benzenesulfonamide was developed. The reaction proceeded readily at 50 °C in formic acid and generated a variety of benzenesulfonamides and aldehydes or ketones simultaneously. The reaction mechanism is believed to be a concerted mechanism that consist of 1,2-aryl migration with the departure of fluorine anion via an SN2 mechanism. This rearrangement reaction features an interesting reaction mechanism, mild reaction conditions, simple operations, and a broad substrate scope.
- Wang, Han-Ying,Pu, Xiao-Qiu,Yang, Xian-Jin
-
p. 13103 - 13110
(2018/10/20)
-
- A packed tower synthesis chlorine acetaldehyde and its production process
-
The invention discloses packed tower synthesized chloroacetaldehyde and a production process thereof. The production process of the packed tower synthesized chloroacetaldehyde comprises steps of packing, heating, reacting, and decompressing and receiving discharged materials, wherein the content of aldehyde in a chloroacetaldehyde solution is more than 10% and the content of acid in the chloroacetaldehyde solution is 13%; a ceramic material is anticorrosive, retention time of gas in pure water is prolonged through corrugated packing, so that reactants react fully and reaction is more sufficient; the content of impurities in a finished product is reduced, production time is shortened and production yield is improved. According to the production process disclosed by the invention, compared with packing-free production, production time is shortened by 20%, yield is improved by 3.2 times and methyl chloroform content is reduced by 60%.
- -
-
Paragraph 0035-0051
(2016/11/07)
-
- METHOD FOR THE CATALYTIC REDUCTION OF ACID CHLORIDES AND IMIDOYL CHLORIDES
-
The present application relates to methods for the catalytic reduction of acid chlorides and/or imidoyl chlorides. The methods comprise reacting the acid chloride or imidoyl chloride with a silane reducing agent in the presence of a catalyst such as [Cp(Pri3P)Ru(NCMe)2]+[PF6]?.
- -
-
Paragraph 0104
(2014/08/19)
-
- Chloroethylating and methylating dual function antineoplastic agents display superior cytotoxicity against repair proficient tumor cells
-
Two new agents based upon the structure of the clinically active prodrug laromustine were synthesized. These agents, 2-(2-chloroethyl)-N-methyl-1,2- bis(methylsulfonyl)-N-nitrosohydrazinecarboxamide (1) and N-(2-chloroethyl)-2- methyl-1,2-bis(methylsulfonyl)-N-nitrosohydrazinecarboxamide (2), were designed to retain the potent chloroethylating and DNA cross-linking functions of laromustine, and gain the ability to methylate DNA at the O-6 position of guanine, while lacking the carbamoylating activity of laromustine. The methylating arm was introduced with the intent of depleting the DNA repair protein O6-alkylguanine-DNA alkyltransferase (AGT). Compound 1 is markedly more cytotoxic than laromustine in both AGT minus EMT6 mouse mammary carcinoma cells and high AGT expressing DU145 human prostate carcinoma cells. DNA cross-linking studies indicated that its cross-linking efficiency is nearly identical to its predicted active decomposition product, 1,2-bis(methylsulfonyl) -1-(2-chloroethyl)hydrazine (90CE), which is also produced by laromustine. AGT ablation studies in DU145 cells demonstrated that 1 can efficiently deplete AGT. Studies assaying methanol and 2-chloroethanol production as a consequence of the methylation and chloroethylation of water by 1 and 2 confirmed their ability to function as methylating and chloroethylating agents and provided insights into the superior activity of 1.
- Zhu, Rui,Baumann, Raymond P.,Patridge, Eric,Penketh, Philip G.,Shyam, Krishnamurthy,Ishiguro, Kimiko,Sartorelli, Alan C.
-
p. 1853 - 1859
(2013/04/10)
-
- Activation reactions of 1,1-dialkoxoalkanes and unsaturated O-donors by titanium tetrafluoride
-
The reactivity of TiF4 with a variety of non cyclic 1,1-dialkoxoalkanes [CH2(OR)2, R = Me, Et, Me 2C(OMe)2, MeCH(OEt)2, ClCH2CH(OEt) 2, CH(OMe)3, PhCCCH(OEt)2], 1,3-dioxolane, N2CHCO2Et and 1,2-epoxybutane has been investigated. Activation, including fragmentation and/or rearrangement of the organic moiety, has been observed at room temperature in some cases; it generally occurs unselectively via C-O bond fission and the formation of new C-O, C-H and C-C bonds. Small differences in the structure of the organic substrate may determine significant differences in the reactivity with TiF4.
- Marchetti, Fabio,Pampaloni, Guido,Biancalana, Lorenzo
-
experimental part
p. 135 - 139
(2012/05/20)
-
- Chemoselective ruthenium-catalyzed reduction of acid chlorides to aldehydes with dimethylphenylsilane
-
A variety of aromatic and alkyl acid chlorides can be selectively converted into aldehydes using dimethylphenyl silane (HSiMe2Ph) as the reducing reagent in the presence of the cationic ruthenium catalyst {Cp[(i-Pr)3P]Ru(NCMe)2}+ [PF6] -. The reactions proceed under very mild conditions and are tolerant to many functional groups. Copyright
- Gutsulyak, Dmitry V.,Nikonov, Georgii I.
-
experimental part
p. 607 - 611
(2012/04/23)
-
- Branching ratios for the reaction of selected carbonyl-containing peroxy radicals with hydroperoxy radicals
-
An important chemical sink for organic peroxy radicals (RO2) in the troposphere is reaction with hydroperoxy radicals (HO2). Although this reaction is typically assumed to form hydroperoxides as the major products (R1a), acetyl peroxy radicals and acetonyl peroxy radicals have been shown to undergo other reactions (R1b) and (R1c) with substantial branching ratios: RO2 + HO2 → ROOH + O2 (R1a), RO 2 + HO2 → ROH + O3 (R1b), RO2 + HO2 → RO + OH + O2 (R1c). Theoretical work suggests that reactions (R1b) and (R1c) may be a general feature of acyl peroxy and α-carbonyl peroxy radicals. In this work, branching ratios for R1a-R1c were derived for six carbonyl-containing peroxy radicals: C2H 5C(O)O2, C3H7C(O)O2, CH3C(O)CH2O2, CH3C(O)CH(O 2)CH3, CH2ClCH(O2)C(O)CH 3, and CH2ClC(CH3)(O2)CHO. Branching ratios for reactions of Cl-atoms with butanal, butanone, methacrolein, and methyl vinyl ketone were also measured as a part of this work. Product yields were determined using a combination of long path Fourier transform infrared spectroscopy, high performance liquid chromatography with fluorescence detection, gas chromatography with flame ionization detection, and gas chromatography-mass spectrometry. The following branching ratios were determined: C2H5C(O)O2, YR1a = 0.35 ± 0.1, YR1b = 0.25 ± 0.1, and YR1c = 0.4 ± 0.1; C3H7C(O)O2, YR1a = 0.24 ± 0.15, YR1b = 0.29 ± 0.1, and YR1c = 0.47 ± 0.15; CH3C(O)CH2O2, Y R1a = 0.75 ± 0.13, YR1b = 0, and YR1c = 0.25 ± 0.13; CH3C(O)CH(O2)CH3, Y R1a = 0.42 ± 0.1, YR1b = 0, and YR1c = 0.58 ± 0.1; CH2ClC(CH3)(O2)CHO, Y R1a = 0.2 ± 0.2, YR1b = 0, and YR1c = 0.8 ± 0.2; and CH2ClCH(O2)C(O)CH3, YR1a = 0.2 ± 0.1, YR1b = 0, and YR1c = 0.8 ± 0.2. The results give insights into possible mechanisms for cycling of OH radicals in the atmosphere.
- Hasson, Alam S.,Tyndall, Geoffrey S.,Orlando, John J.,Singh, Sukhdeep,Hernandez, Samuel Q.,Campbell, Sean,Ibarra, Yesenia
-
experimental part
p. 6264 - 6281
(2012/08/28)
-
- Kinetics and mechanism of the oxidation of aliphatic primary alcohols by imidazolium fluorochromate
-
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
-
experimental part
p. 685 - 692
(2012/04/04)
-
- Synthesis and reactivity of 5-methylenehydantoins
-
5-Methylenehydantoin, as well as the N-mono- and N,N-di-protected derivatives, can be obtained by different synthetic routes. These compounds can undergo a large variety of reactions, such as Diels-Alder, epoxidation, methanol addition and conjugate addition reactions of different types of nucleophiles, including carbon (cyanide), nitrogen (piperidine) and sulfur (thiols, thioacetate) nucleophiles. The reactivity with electrophilic reagents, such as m-CPBA or methanol in acidic medium, and the need for Lewis acids to promote the conjugate addition reactions indicate that hydantoin is a poor electron-withdrawing group.
- Fraile, José M.,Lafuente, Gustavo,Mayoral, José A.,Pallarés, Antonio
-
experimental part
p. 8639 - 8647
(2011/11/30)
-
- Oxidation of aliphatic primary alcohols by morpholinium chlorochromate: A kinetic and mechanistic approach
-
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
-
experimental part
p. 1061 - 1066
(2011/05/05)
-
- Discovery of imidazo[1,2-a]pyrazine-based Aurora kinase inhibitors
-
The synthesis and structure-activity relationships (SAR) of novel, potent imidazo[1,2-a]pyrazine-based Aurora kinase inhibitors are described. The X-ray crystal structure of imidazo[1,2-a]pyrazine Aurora inhibitor 1j is disclosed. Compound 10i was identified as lead compound with a promising overall profile.
- Belanger, David B.,Curran, Patrick J.,Hruza, Alan,Voigt, Johannes,Meng, Zhaoyang,Mandal, Amit K.,Siddiqui, M. Arshad,Basso, Andrea D.,Gray, Kimberly
-
scheme or table
p. 5170 - 5174
(2010/10/02)
-
- Kinetics and mechanism of chlorine-atom-initiated oxidation of allyl alcohol, 3-buten-2-ol, and 2-methyl-3-buten-2-ol
-
The gas-phase reactions of Cl atoms with allyl alcohol (k1), 3-buten-2-ol (k2), and 2-methyl-3-buten-2-ol (k3) at 296 ± 2 K have been investigated using absolute and relative rate methods in 1-700 Torr OfN2 diluent. Absolute rate studies were performed using pulsed laser photolysis/vacuum ultraviolet laser-induced fluorescence spectroscopy techniques. Relative rate studies were performed using smog chamber/Fourier transform infrared spectroscopy techniques. The absolute and relative rate studies gave consistent results. The kinetics of the reactions are dependent on pressure over the range studied. Molar yields for HCl production in 700 Torr of N2 for reactions of chlorine atoms with allyl alcohol, 3-buten-2-ol, and 2-methyl-3-buten-2-ol were measured to be 0.26 ± 0.03, 0.23 ± 0.03, and 0.12 ± 0.02, respectively. The chlorine-atom-initiated oxidation of 2-methyl-3-buten-2-ol in 700 Torr of air gave the following products (molar yields): acetone (47 ± 4%), chloroacetaldehyde (47 ± 5%), and HCHO (7.2 ± 0.6%). The observation of substantial and indistinguishable yields of acetone and chloroacetaldehyde products indicates that a major fraction of the reaction proceeds via addition of chlorine atoms to the terminal carbon atom. The results are discussed with respect to the literature data.
- Takahashi, Kenshi,Xing, Jia-Hua,Hurley, Michael D.,Wallington, Timothy J.
-
experimental part
p. 4224 - 4231
(2010/09/04)
-
- Oxidative regeneration of carbonyl compounds from oximes by morpholinium chlorochromate: A kinetic and mechanistic study
-
The oxidative deoximination of several aldo- and keto-oximes by morpholinium chlorochromate in dimethyl sulphoxide, exhibits a first order dependence on both the oxime and MCC. The oxidation of ketoximes is slower than that of aldoximes. The rate of oxidation of aldoximes correlate . well in terms of Pavelich- Taft dual substituent-parameter equation. The low positive value of polar reaction constant indicates a nucleophilic attack by a chromate oxygen on the carbon. The reaction is subject to steric hindrance by the alkyl groups. The reaction of acetaldoxime has been studied in nineteen different organic solvents. The solvent effect has been analysed by multiparametric equations. A mechanism involving the formation of a cyclic intermediate in the rate-determining step has been proposed.
- Choudhary, Anurag,Agarwal,Sharma, Vinita
-
experimental part
p. 362 - 366
(2010/01/16)
-
- Kinetics and mechanism of the oxidative regeneration of carbonyl compounds from oximes by benzyltrimethylammonium chlorobromate
-
The oxidative deoximination of several aldo- and keto-oximes by benzyltrimethylammonium chlorobromate (BTMACB) in 1:1 (v/v) acetic acid-water is found to be first order with respect to both oximes and BTMACB. The oxidation of ketoximes is slower than that of aldoximes. The rates of oxidation of aldoximes correlated well in terms of Pavelich-Taft dual substituent-parameter equation. The low positive value of polar reaction constant indicated a nucleophilic attack by a chlorobromate ion on the carbonyl carbon. The reaction is subjected to steric hindrance by the alkyl groups. The effect of solvent composition indicated that the rate increases with an increase in the polarity of the solvent. A mechanism involving the formation of a cyclic activated complex, in the rate-determining step, has been proposed.
- Tiwari, Vandana,Barthora, Sonu,Sharma, Monica,Sharma, Vinita
-
experimental part
p. 87 - 91
(2010/05/19)
-
- Terminal aziridines by addition of Grignard reagents or organoceriums to an (α-chloro)sulfinylimine
-
Reaction of N-(2-chloroethylidene)-tert-butylsulfinamide with Grignard reagents or organoceriums gives terminal N-tert-butylsulfinyl aziridines in good yields and (mainly with organoceriums) good diastereomeric ratios. Oxidation of terminal N-tert-butylsu
- Hodgson, David M.,Kloesges, Johannes,Evans, Brian
-
experimental part
p. 1923 - 1932
(2010/01/19)
-
- Kinetics and mechanism of oxidation of aliphatic alcohols by [bis(trifluoroacetoxy)iodo]benzene
-
The oxidation of some aliphatic alcohols by [bis(trifluoroacetoxy)iodo] benzene (TFAIB) in aqueous acetic acid solution leads to the formation of the corresponding carbonyl compounds. The reaction is first order in TFAIB and a Michaelis-Menten kinetics is obtained with respect to the alcohols. The reaction shows a first order dependence on hydrogen ions. The oxidation of [1,1- 2H2]ethanol and [2-2H]propan-2-ol exhibits the presence of a substantial primary kinetic isotope effect at 298 K (k H/kD = 3.64 and 3.89 respectively). The rate of disproportionation of the intermediate is susceptible to both polar and steric effects of the substituents. A suitable mechanism has also been proposed.
- Banerji, Jayshree,Sharma, Pradeep K.,Banerji, Kalyan K.
-
body text
p. 1213 - 1217
(2009/03/11)
-
- Synthesis and in vitro evaluation of imidazopyridazines as novel inhibitors of the malarial kinase PfPK7
-
A high-throughput screening campaign identified a number of imidazopyridazines as novel inhibitors of the malarial kinase PfPK7. Further synthetic chemistry efforts enabled the preparation of a number of analogues with promising in vitro potencies. Although these compounds show likely broad spectrum inhibitory activity, they represent a useful starting point for further chemical optimisation.
- Bouloc, Nathalie,Large, Jonathan M.,Smiljanic, Ela,Whalley, David,Ansell, Keith H.,Edlin, Christopher D.,Bryans, Justin S.
-
scheme or table
p. 5294 - 5298
(2009/05/08)
-
- Total synthesis of (-)-dysithiazolamide
-
(Chemical Equation Presented) The tetrachlorinated natural product (-)-dysithiazolamide was synthesized from L-glutamic acid in a convergent way, confirming the previously proposed (2S,4S,6S,8S) absolute stereochemistry.
- Arda, Ana,Soengas, Raquel G.,Nieto, M. Isabel,Jimenez, Carlos,Rodriguez, Jaime
-
body text
p. 2175 - 2178
(2009/05/26)
-
- Asymmetric synthesis of terminal N-tert-butylsulfinyl aziridines from organoceriums and an α-chloroimine
-
(Chemical Equation Presented) Addition of N-(2-chloroethylidene)-tert- butylsulfinamide to organocerium reagents in DMPU/THF (1:10) at -78°C followed by warming to 25°C provides terminal N-tert-butylsulfinyl aziridines in good yields (63-92%, nine examples) and diastereomeric ratios (85:15->99:1).
- Hodgson, David M.,Kloesges, Johannes,Evans, Brian
-
supporting information; experimental part
p. 2781 - 2783
(2009/05/30)
-
- Synthesis of γ-halogenated and long-chain β-hydroxy-α-amino acids and 2-amino-1,3-diols using threonine aldolases
-
The l- and d-threonine aldolase catalyzed formation of γ-halogenated and long-chain l- and d-3-alkylserine-derivatives 1-12, respectively, was shown starting from glycine and halogenated C2- or C4-C12 aldehydes. lTA from Pseudomonas putida accepted all tested aldehydes with strongly varying diastereoselectivity (de up to 93%). Only aldehydes smaller than decanal were converted by dTA from Alcaligenes xylosoxidans with good selectivities (de up to 73%). Utilizing isobutanal enantio- and diastereopure d-syn-2-amino-3-hydroxy-4-methylpentanoic acid was obtained (ee>99%, de>95%), which was converted to the corresponding 2-amino-1,3-diol.
- Steinreiber, Johannes,Fesko, Kateryna,Mayer, Clemens,Reisinger, Christoph,Schürmann, Martin,Griengl, Herfried
-
p. 8088 - 8093
(2008/02/08)
-
- Kinetics and mechanism of the oxidative regeneration of carbonyl compounds from oximes by quinolinium bromochromate
-
The oxidative deoximination of several aldo- and keto-oximes by quinolinium bromochromate (QBC), in dimethylsulphoxide (DMSO), exhibited a first order dependence on both the oxime and QBC. The oxidation of ketoximes is slower than that of aldoximes. The rates of oxidation of aldoximes correlated well in terms of Pavelich-Taft dual substituent-parameter equation. The low positive value of polar reaction constant indicated a nucleophilic attack by a chromate-oxygen on the carbon. The reaction is subject to steric hindrance by the alkyl groups. The reaction of acetaldoxime has been studied in nineteen different organic solvents. The solvent effect has been analysed by multiparametric equations. A mechanism involving the formation of a cyclic intermediate, in the rate-determining step, has been proposed.
- Bishnoi, Geeta,Sindal,Mishra, Pallavi,Sharma, Pradeep K.
-
p. 458 - 461
(2008/09/21)
-
- Kinetics and mechanism of the oxidation of aliphatic primary alcohols by benzyltriethylammonium chlorochromate
-
The oxidation of nine aliphatic primary alcohols by benzyltriethylammonium chlorochromate (BTEACC) in dimethylsulfoxide (DMSO) leads to the formation of corresponding aldehydes. The reaction is first order with respect to both BTEACC and the alcohol. The reaction is catalysed 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. 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.
- Mishra,Sharma, Monica,Sharma, Vinita
-
p. 364 - 368
(2007/10/03)
-
- Kinetics and mechanism of the oxidative regeneration of carbonyl compounds from oximes by benzyltriethylammonium chlorochromate
-
The oxidative de-oximination of several aldo- and keto-oximes by benzyltriethylammonium chlorochromate (BTEACC), in dimethylsulphoxide (DMSO), exhibited a first-order dependence on both the oxime and BTEACC. The oxidation of keto-oximes is slower than that of aldoximes. The rates of oxidation of aldoximes correlated well in terms of Pavelich-Taft dual substituent-parameter equation. The low positive value of polar reaction constant indicated a nucleophilic attack by a chromate-oxygen on the carbon. The reaction is subject to steric hindrance by the alkyl groups. The reaction of acetaldoxime has been studied in nineteen different organic solvents. The solvent effect has been analysed by multiparametric equations. A mechanism involving the formation of a cyclic intermediate, in the rate-determining step, has been proposed.
- Kaur, Ravdeep,Tiwari, Vandana,Sharma, Vinita
-
p. 1171 - 1174
(2008/02/07)
-
- PROCESS FOR PRODUCING VINYLENE CARBONATE
-
The present invention relates to the industrial production of vinylene carbonate (VC) by elimination of hydrogen chloride from chloroethylene glycol carbonate (CGC) over solid catalysts in the gas phase, the reaction being carried out over a catalyst bed which is agitated by mixing.
- -
-
Page/Page column 6-7; 8-9
(2008/06/13)
-
- Oxidation of ethers with dimethyldioxirane
-
Oxidation of a series of tert-butyl ethers ButOR (R = Me, Et, CH2CH2Cl, Pri, Bui), diethyl ether, diisopropyl ether, 1,2-dimethoxyethane, diisobutoxymethane, 1,4-dioxane, and tetrahydrofuran with dimethyldioxirane (DMDO) was studied. The reaction kinetics obeys the second-order equation w = k[DMDO][ether]. The rate constants in a range of 5-50°C and the activation parameters of the reaction were determined. The solvent effect on the oxidation rate was studied. The oxidation products are the corresponding alcohols and carbonyl compounds. The competition between the nonradical (oxygen insertion) and radical mechanisms of the reaction is discussed. The reactions of the parent dioxirane and DMDO with a series of methyl ethers MeOR′ (R′ = Me, Et, CH2CH2F, Pri) were studied by the density functional theory (DFT). The (U)B3LYP-6-311G(d,p) method was employed to calculate the geometry and energies of the reactants and transition states. The data obtained indicate a possible increase in the probability of oxidation via the radical route and an increase in the activation barrier for the substrates containing electron-withdrawing substituents.
- Grabovskiy,Timerghazin,Kabal'nova
-
p. 2384 - 2393
(2007/10/03)
-
- Kinetics and mechanism of oxidation of alcohols by butyltriphenylphosphonium dichromate
-
Butyltriphenylphosphonium dichromate (BTPPD) oxidizes aliphatic alcohols to the corresponding carbonyl compounds. The reaction is first order in BTPPD. The reaction exhibits a second order dependence each on the alcohol and hydrogen ions. The oxidation of deuteriated ethanol and 2-propanol indicates the presence of a substantial primary kinetic isotope effect. The reaction has been studied in nineteen organic solvents and the solvent effect was analyzed using multiparametric equations. It is observed that the cation-solvating power plays a major role in the reaction. The rate of oxidation shows excellent correlation with the polar and steric substituent constants. Suitable mechanisms have been proposed.
- Kothari, Anita,Kothari, Seema,Banerji, Kalyan K.
-
p. 2039 - 2043
(2007/10/03)
-
- Regioselective alkene carbon-carbon bond cleavage to aldehydes and chemoselective alcohol oxidation of allylic alcohols with hydrogen peroxide catalyzed by [cis-Ru(II)(dmp)2(H2O)2] 2+ (dmp = 2,9-dimethylphenanthroline)
-
(Chemical Equation Presented) [cis-Ru(II)(dmp)2(H 2O)2]2+ (dmp = 2,9-dimethylphenanthroline) was found to be a selective oxidation catalyst using hydrogen peroxide as oxidant. Thus, primary alkenes were very efficiently oxidized via direct carbon-carbon bond cleavage to the corresponding aldehydes as an alternative to ozonolysis. Secondary alkenes were much less reactive, leading to regioselective oxidation of substrates such as 4-vinylcyclohexene and 7-methyl-1,6-octadiene at the terminal position. Primary allylic alcohols were chemoselectively oxidized to the corresponding allylic aldehydes, e.g., geraniol to citral.
- Kogan, Vladimir,Quintal, Miriam M.,Neumann, Ronny
-
p. 5039 - 5042
(2007/10/03)
-
- Kinetics and mechanism of the oxidative regeneration of carbonyl compounds from phenylhydrazones by [bis(trifluoroacetoxy)iodo]benzene
-
The oxidation of several aldo- and keto-phenylhydrazones by [bis(trifluoroacetoxy)iodo]benzene (TFAIB), in aqueous acetic acid leads to the regeneration of the parent carbonyl compounds. The reaction exhibits a first order dependence on both the phenylhydrazone and TFIAB. The oxidation of ketoximes is slower than that of aldoximes. The oxidation of aliphatic phenylhydrazones correlates well in terms of Pavelich-Taft dual substituent-parameter equation. The low positive value of the polar reaction constant indicates a nucleophilic attack by TFIAB on the carbonyl carbon. The reaction is subject to steric hindrance by the alkyl group. A mechanism involving the formation of a cyclic activated complex in the rate-determining step is proposed.
- Kansara, Alpna,Sharma, Pradeep K.,Banerji, Kalyan K.
-
p. 315 - 317
(2007/10/03)
-
- Kinetics and mechanism of the oxidative regeneration of carbonyl compounds from oximes by [bis(trifluoroacetoxy)iodo]benzene
-
The oxidation of several aldo- and keto-oximes by [bis(trifluoroacetoxy) iodo] benzene (TFAIB), in aqueous acetic acid exhibits first order dependence on both the oxime and TFIAB. The oxidation of ketoximes is slower than that of aldoximes. The oxidation of aliphatic oximes correlates well in terms of Pavelich-Taft dual substituent-parameter equation. The reaction constants have positive values. The low positive value of the polar reaction constant indicates a nucleophilic attack by TFIAB on the carbonyl carbon. The reaction is subject to steric hindrance by the alkyl group. A mechanism involving the formation of a cyclic activated complex in the rate-determining step has been proposed.
- Kansara, Alpna,Sharma, Pradeep K.,Banerji, Kalyan K.
-
p. 1056 - 1059
(2007/10/03)
-
- Comparative Effects of Conjugated and Deconjugated Isomeric Enones on the Transannular Diels-Alder Reaction
-
(Equation Presented) Two isomeric cyclic trienones 2 and 3 (with four methyl esters at positions 3 and 10) underwent transannular Diels-Alder (TADA) reaction at very different temperatures. This drastic difference could be traced to the capacity of the en
- Caussanel, Franck,Deslongchamps, Pierre,Dory, Yves L.
-
p. 4799 - 4802
(2007/10/03)
-
- Rate coefficients and mechanisms of the reaction of Cl-atoms with a series of unsaturated hydrocarbons under atmospheric conditions
-
The rate coefficients and mechanisms of the reaction of Cl-atoms with a series of unsaturated hydrocarbons under atmospheric conditions were studied. It was observed the product yielded from both trans-2-butene and 1-butene were found to be oxygen dependent. The results showed that the variation of the product yielded with O2 in the case of 1-butene resulted from competitive reaction pathways for the two β-chlorobutoxy radicals involved in the oxidation.
- Orlando, John J.,Tyndall, Geoffrey S.,Apel, Eric C.,Riemer, Daniel D.,Paulson, Suzanne E.
-
p. 334 - 353
(2007/10/03)
-
- Kinetics and mechanism of the oxidative regeneration of carbonyl compounds from phenylhydrazones by tetraaminecopper(II) bis(permanganate)
-
The oxidation of several aldo- and keto-phenylhydrazones by tetraaminecopper(II) bis(permanganate) (TACP), in aqueous acetic acid, exhibited a first order dependence on both the phenylhydrazone and TACP. Successive scanning of the mixture reaction showed the presence of an excellent isosbestic point. The oxidation of ketophenylhydrazones is slower that than of aldophenylhydrazones. The rates of oxidation of aldophenylhydrazones correlated well in terms of Pavelich-Taft dual substituent-parameter equation. The low positive value of the polar reaction constant indicated a nucleophilic attack by a permanganate-oxygen on the carbon. The reaction is subject to steric hindrance by the alkyl groups. A mechanism involving formation of a cyclic activated complex, in the ratedetermining step, has been proposed.
- Shukla, Raghvendra,Kot, Laszlo,Sharma, Pradeep K.,Banerji, Kalyan K.
-
p. 434 - 444
(2007/10/03)
-
- Kinetics and mechanism of the oxidative regeneration of carbonyl compounds from oximes by tetraamminecopper (II) permanganate
-
The oxidative deoximination of several aldo- and keto-oximes by tetraamminecopper (II) permanganate (TACP), in aqueous acetic acid, exhibits a first order dependence each on both the oxime and TACP. Successive scanning of the reaction mixture has shown the presence of an excellent isosbestic point. The oxidation of ketoximes is slower than that of aldoximes. The rates of oxidation of aldoximes correlate well in terms of Pavelich-Taft dual substituent-parameter equation. The low positive value of polar reaction constant indicates a nucleophilic attack by a permanganate-oxygen on the carbon. The reaction is subject to steric hindrance by the alkyl groups. A mechanism involving the formation of a cyclic intermediate, in the rate-determining step, has been proposed.
- Kumar, Ashok,Mishra, Pallavi,Kontai, Laszlo,Banerji, Kalyan K.
-
-
- Generation of alkyl hypochlorites in oxidation of alcohols with carbon tetrachloride catalyzed by vanadium and manganese compounds
-
Primary alcohols and diols with various structures were subjected to transformations into esters, aldehydes, ketones, and lactones under the action of carbon tetrachloride in the presence of manganese compounds (MnCl 2, MnO2, Mn(OAc)2, Mn(acac)3) and vanadium compounds (VCl5, V2O5, VO(acac) 2) as catalysts. These transformation proceeded with the involvement of alkyl hypochlorites, which were generated in the course of oxidation of alcohols with carbon tetrachloride catalyzed by manganese or vanadium compounds. The optimum molar ratios between the catalyst and reagents were determined, and the reaction conditions for the highly selective synthesis of esters, aldehydes, ketones, and lactones from alcohols were found.
- Khusnutdinov,Shchadneva,Baiguzina,Lavrentieva,Dzhemilev
-
p. 2074 - 2079
(2007/10/03)
-
- Kinetics and mechanism of the oxidative regeneration of carbonyl compounds from oximes by quinolinium fluorochromate
-
The oxidative deoximination of several aldo- and keto-oximes by quinolinium fluorochromate (QFC) in dimethylsulfoxide, exhibited a first order dependence on both the oxime and QFC. The oxidation of ketoximes is slower than that of aldoximes. The rates of oxidation of aldoximes correlated well in terms of Pavelich-Taft dual substituent-parameter equation. The low positive value of polar reaction constant indicated a nucleophilic attack by a chromate-oxygen on the carbon. The reaction is subject to steric hindrance by the alkyl groups. The reaction of acetaldoxime has been studied in nineteen different organic solvents. The solvent effect has been analyzed by multiparametric equations. A mechanism involving the formation of a cyclic intermediate, in the ratedetermining step, has been proposed.
- Dave, Itishri,Sharma, Vinita,Banerji, Kalyan K.
-
p. 347 - 350
(2007/10/03)
-
- Water-soluble derivatives of camptothecin/homocamptothecin
-
Camptothecin and homocamptothecin analogs and derivatives are provided incorporating alkylamine and polyalkylamine moieties.
- -
-
-
- Kinetics and mechanism of the oxidation of aliphatic alcohols by benzyltrimethylammonium dichloroiodate
-
The oxidation of a series of aliphatic alcohols by benzyltrimethylammonium dichloroiodate (BTMACI), in glacial acetic acid in the presence of zinc chloride, leads to the formation of the corresponding carbonyl compounds. The reaction is first order each with respect to the alcohol, zinc chloride and BTMACI. Addition of the benzyltrimethylammonium chloride enhances the rate slightly. The oxidation of deuteriated ethanol indicates the presence of a substantial kinetic isotope effect. [PhCH2Me3N]+[IZn2Cl 6]- is postulated to be the reactive oxidizing species. The reaction is susceptible to both polar and steric effects of the substituents. A mechanism involving transfer of a hydride ion from the alcohol to the oxidant has been proposed.
- Gupta, Poonam,Kothari, Seema
-
p. 474 - 478
(2007/10/03)
-
- Kinetics and Mechanism of the Oxidative Regeneration of Carbonyl Compounds from Oximes by Cetyltrimethylammonium Permanganate
-
The oxidative deoximination of several aldo- and keto-oximes by cetyltrimethylammonium permanganate (CTAP), in dichloromethane, exhibited a first order dependence on both the oxime and CTAP. Successive scanning of the mixture reaction showed the presence of an excellent isosbestic point. The oxidation of ketoximes is slower than that of aldoximes. The rates of oxidation of aldoximes correlated well in terms of Pavelich-Taft dual substituents-parameter equation. The low positive value of polar reaction constant indicated a nucleophilic attack by a permanganate-oxygen on the carbon. The reaction is subject to steric hindrance by the alkyl groups. A mechanism involving the formation of a cyclic intermediate, in the rate-determining step, has been proposed.
- Sankhla, Rekha,Kothari, Seema,Kotai, Laszlo,Banerji, Kalyan K.
-
p. 428 - 439
(2007/10/03)
-
- Kinetics and mechanism of the oxidative regeneration of carbonyl compounds from oximes by pyridinium chlorochromate
-
The oxidative deoximination of several aldo- and keto-oximes by pyridinium chlorochromate (PCC), in dimethyl sulphoxide exhibits a first order dependence on both the oxime and PCC. The oxidation of ketoximes is slower than that of aldoximes. The rates of oxidation of aldoximes correlate well in terms of Pavelich-Taft dual substituent-parameter equation. The low positive value of polar reaction constant indicates a nucleophilic attack by a chromate-oxygen on the carbon. The reaction is subject to steric hindrance by the alkyl groups. The reaction of acetaldoxime has been studied in nineteen different organic solvents. The solvent effect has been analysed by multiparametric equations. A mechanism involving the formation of a cyclic intermediate, in the rate-determining step, has been proposed.
- Bhandari, Abhinav,Sharma, Pradeep K.,Banerji, Kalyan K.
-
p. 470 - 473
(2007/10/03)
-