- Use of N-chloro-N-methyl-p-toluenesulfonamide in N-chlorination reactions
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Second-order rate constants (k2) were determined for the addition of ten nitrogenous organic compounds (benzylamine, 2,2,2- trifluoethylamine chlorhidrate, methylamine chlorhidrate, glycine ethyl ester chlorhidrate, glycine, glycylglycine chlorhidrate, morpholine, pyperidine, pyperazine and dimethylamine) to the N-chloro-N-methyl-p-toluenesulfonamide (NCNMPT) in the formation reaction of N-chloramines in aqueous solution at 25 °C and ionic strength 0.5 M. The series of nucleophiles considered is structurally very varied and covers five pKa units. The kinetic behaviour is similar for all compounds, being the elementary step the transfer of chlorine from the NCNMPT molecule to the nitrogen of the free amino group. These reactions were found first order in both reagents. The values of the rate constants indicate that the more basic amines produce N-chloramines more readily. Rate constants for the nucleophilic attack are shown to correlate with literature data for some of these nitrogenous organic compounds in their reaction with N-methyl-N-nitroso-p-toluenesulfonamide. Both reactions involve that the rate determining step is the attack of nitrogenous compounds upon electrophilic centre (Cl or else NO group). NCNMPT is a particularly interesting substrate, for which has not hitherto been published kinetic information, that allows us to assess the efficiency and the competitiveness of this reaction and compare it with other agents with a Cl+ atom. Copyright 2013 John Wiley & Sons, Ltd. N-chloro-N-methyl-p-toluensulfonamide is a particularly chlorinating agent. The kinetic behaviour has been studied in the formation reaction of N-chloramines using ten nitrogenous compounds. Copyright
- Pastoriza, Cristina,Antelo, Juan Manuel,Crugeiras, Juan
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- Infrared and Raman Spectra, Vibrational Assignment, Normal Coordinate Analysis, and Barrier to Internal Rotation of N-Chloro-N-methylmethanamine
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The infrared (3200-80 cm-1) and Raman (3200-10 cm-1) spectra have been recorded of gaseous and solid N-chloro-N-methylmethanamine (dimethylchloroamine), (CH3)2NCl, and the corresponding deuterium molecules, CH3(CD3)NCl and (CD3)2NCl.Additionally, the Raman spectra of the liquids have been recorded and qualitative depolarization values have been obtained.A complete vibrational assignment is proposed, based on the infrared band contours, Raman depolarization values, group frequencies, and isotopic shifts.The assignment is supported by a normal coordinate analysis which was carried out by utilizing a modified valence force field to calculate the frequencies and the potential energy distribution.The A' and A" methyl torsional fundamentals were observed in the infrared spectrum in the gas phase of the d0 molecule at 281 and 261 cm-1, respectively, from which the threefold barrier to internal rotation is calculated to be 1658 cm-1 (4.74 kcal/mol).From the number of lattice modes observed in the Raman spectrum of the solid, it is concluded that there are at least two molecules per permitive cell.All of these results are compared to similar quantities of some corresponding molecules.
- Durig, J. R.,Lindsay, N. E.,Hizer, T. J.
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- Chemistry of Organic Chloramines. Formation of Arenesulfonamides by Derivatization of Organic Chloramines with Sodium Arenesulfinates
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Organic chloramines react rapidly with sodium benzenesulfinate or sodium toluenesulfinate to form arenesulfonamides.Derivatization was carried out by three different methods, one involving derivatization of pure chloramines and two involving derivatization of the chloramines generated in situ by reaction of the amine with sodium hypochlorite.Seventeen arenesulfonamides whose amine precursors included primary and secondary aliphatic amines, aromatic amines, and amino acids were synthesized in poor to excellent yields depending on the method used.Effects of structure,stability, and water solubility of the chloramine precursors are discussed.Benzenesulfonyl chloride can be isolated from the reaction of 10-4 M N-chloropiperidine with sodium benzenesulfinate.Competing hydrolysis of the sulfonyl chloride accounts for low yields of sulfonamide for dilute solutions of chloramine.
- Scully, Frank E.,Bowdring, Katherine
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- Oxidation of aliphatic amines by aqueous chlorine
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The oxidation of aliphatic amines by aqueous chlorine has been studied. The kinetic behaviour is similar for primary, secondary and tertiary aliphatic amines the elementary stop being the transfer of chlorine from the hypochlorous acid molecule to the nitrogen of the free amine group. Chlorination of aliphatic primary and secondary amines involves some water molecules in the transition state. Inductive effects are also discussed.
- Abia,Armesto,Canle L.,Garcia,Santaballa
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- Reactions of chlorination with tert-butyl hypochlorite (TBuOCl)
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The chlorination reactions of nitrogenous organic compounds (2,2,2-trifluoroethylamine, benzylamine, glycine, and dimethylamine) by tert-butyl hypochlorite (tBuOCl) were studied at 25°C, ionic strength 0.5 M and under isolation conditions. The kinetic results obtained in the formation processes of the corresponding N-chloramines in acid medium (pH = 5-7) are summarized in this paper. Kinetic studies showed a first order with respect to tBuOCl concentration. The chlorination reactions involving benzylamine, glycine and dimethylamine were all first order with respect to nitrogenous compound concentration and approximately -1 order with respect to proton concentration. The reaction with 2,2,2-trifluoroethylamine was more complex, and the order of reaction with respect to the amine varied with pH.
- Pastoriza, Cristina,Antelo, Juan Manuel,Crugeiras, Juan
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- Two-step continuous flow synthesis of amide via oxidative amidation of methylarene
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A green and efficient method for the synthesis of amides has been developed through oxidative amidation between methylarenes with amines in a two-step continuous flow system. This method integrates methylarene oxidation and amide formation into a single operation which is usually accomplished separately. Oxidation with tert-butyl hydroperoxide (TBHP) as “green” oxidant, the synthesis of amides under mild reaction conditions in continuous flow system and the utilization of methylarenes as starting material make this methodology novel and environment friendly. The practical value of this method is highlighted through the synthesis of high-profile pharmaceutical agents, acetylprocainamide.
- Fang, Zheng,Guo, Kai,He, Wei,Liu, Chengkou,Shi, Tingting,Yang, Yuhang,Yang, Zhao,Zhang, Zhimin
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supporting information
(2020/02/28)
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- Too Short-Lived or Not Existing Species: N-Azidoamines Reinvestigated
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Treatment of N-chlorodimethylamine with sodium azide in dichloromethane does not lead to N-azidodimethylamine, as thought for more than 50 years. Instead, surprisingly, (azidomethyl)dimethylamine is generated with good reproducibility. A plausible reaction mechanism to explain the formation of this product is presented. The reaction of lithium dibenzylhydrazide with tosyl azide does not result in the creation of an N-azidoamine, which can be detected by IR spectroscopy at ambient temperature, as it was claimed previously. Additional experiments with diazo group transfer to lithium hydrazides show that intermediate N-azidoamines are very short-lived or their formation is bypassed by direct generation of 1,1-diazenes via synchronous cleavage of two N-N bonds.
- Banert, Klaus,Pester, Tom
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p. 4033 - 4039
(2019/04/10)
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- Practical and regioselective amination of arenes using alkyl amines
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The formation of carbon–nitrogen bonds for the preparation of aromatic amines is among the top five reactions carried out globally for the production of high-value materials, ranging from from bulk chemicals to pharmaceuticals and polymers. As a result of this ubiquity and diversity, methods for their preparation impact the full spectrum of chemical syntheses in academia and industry. In general, these molecules are assembled through the stepwise introduction of a reactivity handle in place of an aromatic C–H bond (that is, a nitro group, halogen or boronic acid) and a subsequent functionalization or cross-coupling. Here we show that aromatic amines can be constructed by direct reaction of arenes and alkyl amines using photocatalysis, without the need for pre-functionalization. The process enables the easy preparation of advanced building blocks, tolerates a broad range of functionalities, and multigram scale can be achieved via a batch-to-flow protocol. The merit of this strategy as a late-stage functionalization platform has been demonstrated by the modification of several drugs, agrochemicals, peptides, chiral catalysts, polymers and organometallic complexes.
- Ruffoni, Alessandro,Juliá, Fabio,Svejstrup, Thomas D.,McMillan, Alastair J.,Douglas, James J.,Leonori, Daniele
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p. 426 - 433
(2019/05/01)
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- Copper-catalyzed one-pot oxidative amidation of alcohol to amide via C-H activation
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A one-pot oxidative amidation of both aliphatic and aromatic alcohols with N-chloramines, prepared in situ from many types of primary and secondary amines, was developed. This cross-coupling reaction integrates alcohol oxidation and amide bond formation, which are usually accomplished separately, into a single operation. And it was green, simple and convenient, which has a wide substrate scope and makes use of cheap, abundant, and easily available reagents. The practical value of this method is highlighted through the synthesis of a high-profile pharmaceutical agent, acetylprocainamide.
- Gu, Jiajia,Fang, Zheng,Yang, Yuhang,Yang, Zhao,Wan, Li,Li, Xin,Wei, Ping,Guo, Kai
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p. 89413 - 89416
(2016/10/03)
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- Reactions of chlorination with tert-butyl hypochlorite (TBuOCl)
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The chlorination reactions of nitrogenous organic compounds (2,2,2-trifluoroethylamine, benzylamine, glycine, and dimethylamine) by tert-butyl hypochlorite (tBuOCl) were studied at 25°C, ionic strength 0.5 M and under isolation conditions. The kinetic results obtained in the formation processes of the corresponding N-chloramines in acid medium (pH = 5-7) are summarized in this paper. Kinetic studies showed a first order with respect to tBuOCl concentration. The chlorination reactions involving benzylamine, glycine and dimethylamine were all first order with respect to nitrogenous compound concentration and approximately -1 order with respect to proton concentration. The reaction with 2,2,2-trifluoroethylamine was more complex, and the order of reaction with respect to the amine varied with pH.
- Pastoriza, Cristina,Antelo, Juan Manuel,Crugeiras, Juan
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supporting information
p. 952 - 959
(2015/08/25)
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- Acid-catalysed chlorine transfer from N-chloramines to iodide ion: Experimental evidence for a predicted change in mechanism
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Rate constants for acid catalysis of the reactions of N-chlorodimethylamine (1), N-chloro-2,2,2-trifluoroethylamine (2) and N,N-dichlorotaurine (3) with iodide ion were determined in H2O at 25°C and I = 0.5 (NaClO 4). The failure to detect significant catalysis by general acids of chlorine transfer from 1 to the nucleophile, together with the observed inverse solvent deuterium isotope effect on the hydronium ion-catalysed reaction (k H/kD = 0.37), indicates that this process occurs by protonation of 1 in a fast equilibrium step, followed by rate determining chlorine transfer to iodide ion. The appearance of general acid catalysis for the reactions of 2 and 3 shows that increasing the leaving group ability leads to a change to a concerted mechanism, which is suggested to be enforced by the absence of a significant lifetime of the protonated chloramine intermediate in the presence of iodide ion.
- Calvo, Paula,Crugeiras, Juan,Rios, Ana
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experimental part
p. 4137 - 4142
(2010/10/19)
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- Kinetic and thermodynamic barriers to chlorine transfer between amines in aqueous solution
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(Chemical Equation Presented) Third-order rate constants for the acid-catalyzed reversible reaction of N-chlorotaurine with benzylamine and dimethylamine were determined in water at 25°C and I = 0.5 (NaClO 4). The reaction with benzylamine shows inverse solvent deuterium isotope effects of kH/kD = 0.57 and 0.47 in the forward and reverse directions, respectively. These isotope effects, together with the absence of detectable general acid catalysis for this reaction, provide evidence for a stepwise mechanism involving fast equilibrium protonation of N-chlorotaurine followed by rate-determining chlorine transfer from the protonated chloramine to benzylamine. The observation of strong catalysis by general acids of the reaction of dimethylamine with N-chlorotaurine suggests a change to a concerted mechanism with proton and chlorine transfer occurring in a single step. This change in mechanism is enforced by the absence of a significant lifetime for protonated chlorotaurine in contact with this strongly nucleophilic amine. The kinetic and thermodynamic parameters for the reaction between protonated chlorotaurine and benzylamine are used to estimate a Marcus intrinsic reaction barrier of ΔG0? = 4.1 kcal/mol for chlorine transfer between amines. Comparison of this intrinsic barrier with those reported previously for bromine transfer between carbanions points to the existence of certain similarities between halogen and proton transfer reactions.
- Calvo, Paula,Crugeiras, Juan,Rios, Ana
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experimental part
p. 5381 - 5389
(2009/12/03)
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- Ammonia-dimethylchloramine system: Kinetic approach in an aqueous medium and comparison with the mechanism involving liquid ammonia
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After an exhaustive study of the system ammonia-dimethylchloramine in liquid ammonia, it was interesting to compare the reactivity of this system in liquid ammonia with the same system in an aqueous medium. Dimethylchloramine prepared in a pure state undergoes dehydrohalogenation in an alkaline medium: the principal products formed are N-methylmethanimine, 1,3,5- trimethylhexahydrotriazine, formaldehyde, and methylamine. The kinetics of this reaction was studied by UV, GC, and HPLC as a function of temperature, initial concentrations of sodium hydroxide, and chlorinated derivative. The reaction is of the second order and obeys an E2 mechanism (k1 =4.2 × 10-5 M-1 s-1, ΔH# = 82 kJ mol-1, ΔS# = -59 J mol-1 K-1) The oxidation of unsymmetrical dimethylhydrazine by dimethylchloramine involves two consecutive processes. The first step follows a first-order law with respect to haloamine and hydrazine, leading to the formation of an aminonitrene intermediate (k2 = 150 × 10-5 M-1 s -1). The second step corresponds to the conversion of aminonitrene into formaldehyde dimethylhydrazone at pH 13). This reaction follows a first-order law (k3 = 23.5 × 10-5 s-1) The dimethylchloramine-ammonia interaction corresponds to a SN2 bimoiecular mechanism (k4 = 0.9 × 10-5 M-1 s -1, pH 13, and T =25°C). The kinetic model formulated on the basis of the above reactions shows that the formation of the hydrazine in an aqueous medium comes under strong competition from the dehydrohalogenation of dimethylchloramine and the oxidation of the hydrazine formed by the original chlorinated derivative. A global model that explains the mechanisms both in an anhydrous and in an aqueous medium was elaborated.
- Stephan,Pasquet,Elkhatib,Goutelle,Delalu
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p. 340 - 351
(2008/09/21)
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- Interaction between substituted chloramines and liquid ammonia using the indirect Raschig process
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In this paper, different hydrazines are synthesised by the indirect Raschig process. This consists of introducing a substituted chloramine (R 1R2NCl) into liquid ammonia under pressure to obtain the corresponding hydrazine (R1R2NNH2). The experimental results, in disagreement with those reported in the literature, lead us to propose a new mechanistic scheme involving a chlorine transfer reaction. Thus, the formation of chloramine (NH2Cl) and the amine (R1R2NH) occurs first. Chloramine reacts immediately with the substituted amine, in agreement with the direct Raschig process, to produce the hydrazine. Under these conditions, the nature of the hydrazine is kinetically controlled by the excess amine. It is then possible to synthesise different hydrazines from the same substituted chloramine. This mechanism is validated by the following syntheses: unsymmetric dimethylhydrazine (UDMH), N-aminopiperidine (NAPP) and N-amino 3-azabicyclo[3.3.0]octane (NAZA).
- Stephan, Juliette,Berthet, Jacques,Goutelle, Veronique,Pasquet, Veronique,Delalu, Henri
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p. 808 - 812
(2007/10/03)
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- Kinetics and mechanism of chlorine exchange between chloramine-T and secondary amines
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The kinetics and mechanisms of chlorine transfer from chloramine-T (CAT) to several amines are second order and independent of p-toluenesulfonamide concentration; thus, the reaction does not involve disproportionation of CAT to dichloramine-T. From the profile of pH versus rate, the following mechanisms were proposed: (1) reaction of the ionized species of CAT with the ionized amine (ionic mechanism) and (2) reaction of the un-ionized species of CAT with the un-ionized amine (nonionic mechanism). The second-order, pH- independent rate constants calculated for the ionic and nonionic mechanisms were 1.6 and 5 x 106 M-1 s-1, respectively. Although these two mechanisms are kinetically indistinguishable, the rate constant for the nonionic mechanism is of the same order of magnitude as those calculated for similar chlorination reactions involving nonionizable chloramines, such as N- chlorosuccinimide, N-chloroquinuclidine, and N-chloro-N- methylbenzenesulfonamide. The proposed mechanism for the chlorine exchange involves a molecule of water in a cyclic, six-membered transition state.
- Dannan,Crooks,Dittert,Hussain
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p. 652 - 656
(2007/10/02)
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- ELECTROCHEMICAL CHLORINATION OF AMINES
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We have studied the laws governing the electrochemical chlorination of primary and secondary amines in aqueous solution on a ruthenium-titanium anode under conditions of diaphragm electrolysis.It was found that in order to ensure the most complete conversion of the amines into the corresponding chloramines it is necessary to add NaHCO3 to the electrolyte .Under the conditions of electrolysis primary amines are converted almost quantitatively into dichloramines.High yields of the N-chloro-derivatives of secondary amines can be obtained with high current densities and concentrations of NaCl.
- Petrosyan, V. A.,Lyalin, B. V.,Smetanin, A. V.
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p. 542 - 546
(2007/10/02)
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- MODELISATION GENERALE DES PROCESSUS REACTIONNELS INTERVENANT AU COURS DE LA SYNTHESE DE LA DIMETHYLHYDRAZINE ASYMETRIQUE PAR LE PROCEDE RASCHIG. QUANTIFICATION DES PRODUITS DE DEGRADATION (HYDRAZONE). I. FORMULATION DU MODELE. VALIDITE EN MILIEU DILUE. INTERPRETATION
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A kinetic model of Unsymetrical dimethylhydrazine (UDMH) formation by Raschig process has been established.Its application range runs from pH = 8 to 14.64 (4 mol.l-1 NaOH).The synthesis is controlled by the acid-base dissociation equilibria : (NH2Cl NHCl- + H+; (CH3)2NH2(+) (CH3)2NH + H+; (CH3)2NHNH2+ (CH3)2NNH2 + H+) and by the following elementary reactions : -Dimethylhydrazine elaboration molecular (NH2Cl / (CH3)2NH) and ionic (NHCl- / (CH3)2NH) processes -Dimethylchloramine formation from NH2Cl and (CH3)2NH2+ -UDMH catalytic oxidation by NH2Cl and dimethyldiazene (CH3)2N+=N- intermediate formation -Diazene decomposition to yield formaldehyde dimethylhydrazone (FDMH) -Degradation of (CH3)2N+=N- by NH2Cl -Alkaline hydrolysis of chloramine.The synthesis can be expressed by a differential system of which the integration allows to foresee the evolution of mixtures in terms of concentration, pH and temperature.In particular, it allows a numeric evaluation of FDMH, troublesome by-product of the UDMH manufacture.Significant examples selected in different pH ranges and concentration have permitted to test the coherence between experimental and calculated curves.
- Delalu, H.,Marchand, A.
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p. 2149 - 2162
(2007/10/02)
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- INFLUENCE D'UNE IONISATION DES REACTIFS SUR L'ASPECT MECANISTIQUE DE L'INTERACTION CHLORAMINE-DIMETHYLAMINE. FORMATION PARALLELE DE DIMETHYL-HYDRAZINE ET DE DIMETHYLCHLORAMINE
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The effect of acidification on the chloramine-dimethylamine reactivity has been investigated as a function of pH (13-8) and temperature (292-305 K).Kinetics results show the existence of two competitives reactions involving chloramine with neutral and ionic form of the amine.They lead respectively, according to a second order process, to the formation of dimethylhydrazine (k1 = 68. 1E-3 1. mol-1. s-1; T = 298 K) and dimethylchloramine (k2 = 210. 1E-3 1. mol-1. s-1; T = 298 K).The rate bimolecular constant calculated form the total concentration of reactives may be expressed by an equation of the from kobs = k1αΛ + k2βΑ, where αΛ and βΛ are coefficients which depend on pH and the protonation constant of dimethylamine.The enthalpy and entropy of activation for the ionic process have been determinated at 298 K.Another mechanism involving NH3Cl+ and (CH3)2NH has been discussed and a correlation between the two models established.
- Delalu, H.,Marchand, A.
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p. 1941 - 1954
(2007/10/02)
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- Etude cinetique de la N-chloration de la dimethylamine et de la diethylamine en phase aqueuse
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A complete kinetic study of the N-chlorination, in aqueous medium, of dimethylamine and diethylamine by a stopflow spectrophotometric method is presented.In neutral or basic medium our experimental results can be interpreted by two kinetically indistinguishable mechanisms; the reactin between protonated amine (R2NH2+) and hypochlorite ion (ClO-) and the reaction between R2NH and hypochlorous acid (ClOH) are equivalent because of the fast equilibrium of proton exchange existing between the two groups of possible reactants (R2NH + ClOH = ClO- + R2NH2+).In acid medium, in the presence of chloride ions, we observed a reaction by aqueous chlorine (Cl2) on the amine (Cl2 + R2NH = chloramine). Key words: kinetics, N-chlorination, amines, aqueous medium.
- Matte, Denise,Solastiouk, Bernard,Merlin, Andre,Deglise, Xavier
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p. 786 - 791
(2007/10/02)
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- INTERACTION ENTRE LE CHLORE DE LA MONOCHLORAMINE ET L'AZOTE DES COMPOSES AMINES. FORMATION DE CHLORAMINES SUBSTITUEES
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At 25 deg C and in the pH range from 8 to 13, the kinetics and the equilibrium constant for the chlorine transfer reaction between monochloramine NH2Cl and the amines: CH3NH2, C2H5NH2, (CH3)2CHNH2, (CH3)2NH and (C2H5)2NH are investigated by spectrophotometry in aqueous medium with an ionic strength practically constant and equal to 1.03+/-0.05 M and for a concentration of total ammonia equal to 1 M.The reaction is first order with respect to each reactant and the observed rate constant, practically pH independent below 8 and above 12.8, reaches a maximum located between the pKa's of NH4+ and RR'NH2+ and depending on the nature and the concentration of the constituents used to fix pH.The reaction proceeds through two pathways involving interactions between NH2Cl and RR'NH or RR'NH2+ for which the proper rate constants are modelized according to the pKa and the substituents of each amine.
- Ferriol, Michel,Gazet, Josette,Saugier-Cohen Adad, Marie-Therese
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p. 1955 - 1978
(2007/10/02)
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- SYNTHESE D'IMINES LINEAIRES NON-STABILISEES PAR REACTIONS GAZ-SOLIDE SOUS VIDE(1).
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Unstabilized imines are synthetized in gram-scale by vacuum dehydrochlorination of N-chloroalkylamines and by vacuum dehydrocyanation of α-aminonitriles on solid base.All the new compounds are characterized at low temperature by 1H, 13C NMR and IR spectroscopy.
- Guillemin, Jean-Claude,Denis, Jean-Marc
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p. 4431 - 4446
(2007/10/02)
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- Process for preparing hydrazines
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Substantially anhydrous hydrocarbyl-substituted chloramine is efficiently prepared by reacting a primary or secondary amine with a chlorinating agent selected from hypochlorous acid or chlorine monoxide in a non-aqueous reaction medium, without co-production of an amine hydrochloride salt.
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- Gasphase Reactions, 60. - Methanimines RR'C=NR'': Preparation and Photoelectron Spectra
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Methanimines RR'C=NR'' (R, R', R'' = H, CH3) are prepared by pyrolysis of alkyl azides, or by consecutive chlorination of gaseous alkylamines at solid N-chlorosuccinimide and dehydrochlorination of the resulting N-chloroamines by passage over potassium tert-butylate in flow reactors; the reaction conditions are advantageously optimized applying PE spectroscopic realtime analysis.Their ionization patterns are assigned based on geometry-optimized MNDO calculations, radical cation state comparison, and the vibrational fine structures of individual bands.Despite their tendency to polymerize, the compounds may be condensed as monomers at low temperature and characterized by NMR.Reevaporated methanimine decomposes into H2 and HCN only above 1300 K, i.e. relative to its formation as "chemically activated" product in the methyl azide pyrolysis at a temperature higher by over 500 K.The chlorination of cyclopropylamine followed by dehydrochlorination yields a reaction mixture containing large amounts of hitherto unknown cyclopropanimine (H2C)2C=NH.
- Bock, Hans,Dammel, Ralph
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p. 1961 - 1970
(2007/10/02)
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- ASYMMETRICAL NITROGEN-40; GEMINAL SYSTEM-26. N-CHLOROHYDRAZINES
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The factors determining the kinetic and thermodynamic stabilities of N-chlorohydrazines are discussed.Acyclic N-chlorohydrazines exist only as trialkyldiazenium chlorides 3a,b.Chlorination of 2-acyl-1,1-dimethylhydrazines 6a,b gave 1,4-diacyl-2,3-dimethylhexahydro-1,2,4,5-tetrazines 7a,b via hydrazyl radical intermediates, and chlorination of a 1-phenylpyrazolidin-5-one 8 gave phenylazoisovaleric esters 9a,b.Stable N-chlorohydrazines were obtained from bicyclic hydrazines; viz. the 2-chloro-1.2-diazabicyclo(2.2.2.)octan-3-one 12 and 7-chloro-1,7-diazabicyclo(2.2.1)heptane 16.The restricted inversion of N(7) in 16 and its 1-methyl quate rnary salt 21 were observed in the 13C-NMR spectra.The acyclic N-chlorohydrazinium salt 25 was isolated.
- Shustov, G. V.,Tavakalyan, N. B.,Kostyanovsky, R. G.
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p. 575 - 584
(2007/10/02)
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- Vacuum Gas/Solid N-Chlorination: Preparative Scale Synthesis of Volatile N-Chloramines
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A simple method for the preparative scale synthesis of volatile chloramines free from impurities starting from the corresponding primary or secondary amine using N-chlorosuccinimide as chlorinating agent is described.
- Guillemin, J. C.,Denis, J. M.
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p. 1131 - 1133
(2007/10/02)
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- POLAR RADICALS XVIII. ON THE MECHANISM OF CHLORINATION BY N-CHLOROAMINES: INTERMOLECULAR AND INTRAMOLECULAR ABSTRACTION.
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The photochlorinations of the n-butyl, n-pentyl, and n-hexyltrimethylammonium chlorides, using molecular chlorine in hexachloroacetone or 15percent CD3CO2D/85percent H2SO4, or using N-chlorodimethylamine in the acid solvent are described.The ammonium group exerted a strong polar directing effect upon the site of substitution.This effect was found to be more pronounced in the more polar protic solvent.The reagent, N-chlorodimethylamine, generated the dimethylamminium radical, whose reaction showed a polar sensitivity toward hydrogen abstraction similar to that of the chlorine atom, but exhibiting a much greater secondary/primary selectivity.Comparison of the isomer distributions obtained from the self photochlorination reactions of N-chloro-n-hexylmethylamine and N-chloro-n-pentylmethylamine in the acid solvent, with the distribution pattern obtained for the chlorinations of the ammonium salts with N-chlorodimethylamine, suggested that the self chlorinations of the N-chloroamines proceed by the intramolecular hydrogen abstraction mechanism suggested previously.
- Tanner, Dennis D.,Arhart, Richard,Meintzer, Christian P.
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p. 4261 - 4278
(2007/10/02)
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- Etude par resonance magnetique multinucleaire d'intermediaires reactionnels electrophiles. Partie 8. Action des acides de Lewis chlores COCl2, POCl3, (CH3)2N=CHCl+Cl- et Cl2 sur l'hexamethylphosphotriamide (HMPT)
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The structural study of the electrophilic intermediates obtained from carboxamides and chlorinated Lewis acids is extended to the phosphoric amides.The action of COCl2 and POCl3 on hexamethylphosphotriamide (HMPT) can lead to a chlorophosphonium salt (3a) the structure of which is proved by nmr spectroscopy (1H, 13C, 31P, 15N).The mechanism of formation is comparable to that of the chloroiminium chloride (Vilsmeyer reagent) from the corresponding amides.The action of chlorine on HMPT does not lead to a stable salt of the same kind but essentially to the substitution product(2).A new biphosphorylated compound (6) has been identified when an excess of chlorine is reacted with HMPT.
- Poignant, S.,Gauvreau, J.R.,Martin, G.J.
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p. 946 - 952
(2007/10/02)
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- Alkyltin cyclopropylcarbinylsulfonate
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Pesticidal and anti-inflammatory cyclopropyl compounds, cyclopropyl intermediates for the preparation of pesticidal compounds, especially chrysanthemic acid-like intermediates, and a process for preparing same.
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