Reactivity of α-amino acids in the N-acylation with benzoic acid esters in aqueous dioxane

Ishkulova, N. R.; Oparina, L. E.; Kochetova, L. B.; Kustova, T. P.; Калинина, Н. В.; Kuritsin, L. V.

doi:10.1134/s1070363210050178

Cited by 6 publications

(7 citation statements)

References 3 publications

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“…They were 48± 3 kJ mol -1 and -124±9 J mol -1 K -1 respectively. These values agree with the reported data on the activation energies and entropies of the reactions of aliphatic amines and α-amino acids with esters under the analogous conditions [9][10][11][12]15] showing that these reactions proceed according to common mechanisms while performing them in water-organic media.…”

Section: Kuritsyn Et Al 886supporting

confidence: 92%

“…These dependences are characterized by Eqs. (17) Obtained results confirm the assumption on the dependence between the reactivity of the participants of acylation and the orbital characteristics of their molecules [12].…”

Section: Kuritsyn Et Al 886supporting

confidence: 88%

“…(15), (16) are 1.9×10 -4 and 2.8×10 -3 l mol -1 s -1 respectively. These values coincide with the constants of the reaction of glycine with ester VIII in water-2-propanol (2.1×10 -4 l mol -1 s -1 ) [10] and water-dioxane (1.3×10 -3 l mol -1 s -1 ) [12] mixtures. In the reactions with cyclohexylamine as well as in the reactions with glycine these values are significantly lower than the rate constants of aminolysis of nitro-substituted esters showing the determining effect of substituents in the phenoxide species on the reactivity of esters under investigation.…”

Section: Kuritsyn Et Al 886supporting

confidence: 58%

“…We have developed procedures permitting strict accounting for the effect of pH and hydrolysis of acylating agents while calculation of acylation rate constants. Together with these studies quantum-chemical simulation of the reaction mechanisms and state of reagents in solution [12] was carried out. The aim of these studies is the investigation of structure of acylating agents like 2-,3-, and 4-nitrophenyl I-III; 2,4-, 2,5-, and 2,6-dinitrophenyl IV-VI, and 2,4,6-trinitrophenyl VII benzoates on the kinetics of their reaction with cyclohexyl amine.…”

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Kinetics of acylation of cyclohexylamine with substituted phenyl benzoates

et al. 2012

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Kinetics of acylation of cyclohexylamine with nitro-substituted phenyl benzoates is studied in water solutions of 2-propanol and dioxane. By means of RHF/6-31G* method quantum-chemical simulation of ester molecules and of cyclohexylamine solvatocomplexes was carried out. On the basis of correlation of rate constants and LUMO energies of esters and population of 2p z -orbitals of carbon atom of the acyl group a conclusion on the orbital control of the reactions was made.An interest to the products of acylation of amines is caused by their wide use as polymers, dyes, surfactants, biologically active compounds, and drugs of wide spectrum of action. Optimization of conditions of the industrial synthesis of these substances requires performing kinetic studies and establishing quantitative dependences of rate constants of the abovementioned processes on the structure of reagents and the effect of medium. In the series of studies kinetics is explored and the mechanisms are established of the reactions of aromatic and aliphatic amines with different acylating agents, among them with the carboxylic acid esters in the aprotic non-polar media. Kinetic data on the aminolysis of esters in water and some water-organic solvents are also mentioned [1][2][3][4][5][6][7].In the course of years we study the acyl transfer reactions with the participation of different amines (aromatic, aliphatic including α-amino acids, and mixed). Aroyl and sulfonyl chlorides and also phenyl carboxylates were used as acylating agents. Specific feature of aminolysis of esters in water-containing media is the possibility of parallel proceeding of hydrolysis. The most important factor affecting the rate of aminolysis and hydrolysis is the pH of medium [8][9][10][11]. Note that adequate attention to the consideration of these factors rather scarce [6,7]. We have developed procedures permitting strict accounting for the effect of pH and hydrolysis of acylating agents while calculation of acylation rate constants. Together with these studies quantum-chemical simulation of the reaction mechanisms and state of reagents in solution [12] was carried out. The aim of these studies is the investigation of structure of acylating agents like 2-,3-, and 4-nitrophenyl I-III; 2,4-, 2,5-, and 2,6-dinitrophenyl IV-VI, and 2,4,6-trinitrophenyl VII benzoates on the kinetics of their reaction with cyclohexyl amine. Binary mixtures of water (molar fraction 0.73) with 2-propanol (i-PrOH) and dioxane (Diox) were used as solvents.Reaction of cyclohexylamine with esters under the conditions of kinetic experiments (pH 8.8) proceeds according to Eqs. (1)-(4) where R 1 is mono-, di-or trinitrosubstituted phenyl, k ac , k(H 2 O), and k OH -are rate constants of the processes (1)-(3). fast According to the Eqs. (1)-(4) the rate of change in the concentration of ester (c es ) in the kinetic experiment is described by Eqs. (5), (6).-(dc ef )/(dτ) = k ac с а с ef + k(H 2 O)c(H 2 O)c ef + k OH -с OH -с ef = k obs c ef ,k obs = k ac с а + k(H 2 O)c(H 2 O) + k OH -c OH -.

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Section: Kuritsyn Et Al 886supporting

confidence: 92%

Section: Kuritsyn Et Al 886supporting

confidence: 88%

Section: Kuritsyn Et Al 886supporting

confidence: 58%

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Kinetics of acylation of cyclohexylamine with substituted phenyl benzoates

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“…2), which is indicative of an important role of specific solvation of amines and transition states of the reaction of acylation. The solvation of the acylation reagents in the reaction of the acyl group transfer, according to the available data [7,[10][11][12][13], plays a subordinate role. Table 3 presents the results of the kinetic study of the reactions of piperidine and morpholine with compounds I and II in the system water (40 wt %)dioxane.…”

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Acylation of piperidine and morpholine with phenyl benzoates in the mixtures water-2-propanol and water-dioxane

et al. 2015

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Kinetics of acylation of piperidine and morpholine with 4-nitro-and 2,6-dinitrophenyl benzoates was studied in binary systems water-2-propanol and water-dioxane. Structural and energy characteristics of solvate complexes of morpholine and piperidine with the components of the mixed solvents were calculated. Kinetic regularities of acylation are considered from the viewpoint of specific solvation of amines.

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Towards mechanisms of bimolecular nucleophilic reactions in solution—probing the variation of the activation parameters in the reactions of aromatic compounds

Vlasov

2011

J of Physical Organic Chem

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Variation of the activation parameters in the SN2, acyl‐transfer, SNAr, SNV, and AdN reactions offers a uniquely useful probe for the mechanistic features of these reactions in solution. New approach uses the substituent effects on the aromatic ring to the variation of the activation parameters, ΔH≠ and ΔS≠, in the above reactions in the frameworks of the Hammett‐like equations in order to evaluate the resultant δΔH≠ and δΔS≠ reaction constants. Compensation relationships of δΔH≠ versus δΔS≠ allow one to estimate the contribution of changes of the internal enthalpy, δΔH≠int, to the enthalpy reaction constant, δΔH≠, that is inherent to bimolecular nucleophilic reactions and gives a single linear dependence on the Hammett ρ reaction constants for these reactions. The deviations from dependence of δΔH≠int versus ρ serve as useful points of interpretation of changes of the transition state structure or reaction mechanism. The results obtained show that the substituent effects in the substrates, nucleophiles, and leaving groups on the mechanistic features in bimolecular nucleophilic reactions are governed by the magnitude of δΔH≠int. Copyright © 2011 John Wiley & Sons, Ltd.

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Reactivity of α-amino acids in the N-acylation with benzoic acid esters in aqueous dioxane

Cited by 6 publications

References 3 publications

Kinetics of acylation of cyclohexylamine with substituted phenyl benzoates

Kinetics of acylation of cyclohexylamine with substituted phenyl benzoates

Acylation of piperidine and morpholine with phenyl benzoates in the mixtures water-2-propanol and water-dioxane

Towards mechanisms of bimolecular nucleophilic reactions in solution—probing the variation of the activation parameters in the reactions of aromatic compounds

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