Kinetics of the reaction of N-2, 6-tri-chlorobenzoquinonimine with sodium thiosulphate in methanol-water mixtures

The kinetics of the reaction of N-2,6-trichlorobenzoquinonimine with sodium thiosulfate has been studied in methanol-water mixtures over the temperature range 25-40C. The rates were found to increase with increasing dielectric constant. The reaction was found to obey the Arrhenius equation. The energy of activation and the thermodynamic parameters of activation were calculated and discussed as evidence of solvation effects

Kinetics of addition of aromatic amines on trans-3- [P-Substituted phenyl] -1- Phenyl-Prop-2-En-1-Ones

The reactions of a series of trans-3-[p-substituted phenyl]-1-phenyl- prop-2-en-1-ones Ia-e with p-anisidine and p-nitroaniline IIa,b were studied in methanol, and their reaction rates were measured. The reaction followed a second order kinetics. In addition, the activation parameters delta H* and delta S* for the reactions of both amines were calculated and led to the conclusion of a cyclic multistep mechanism for that amine. Michael addition reaction involving one molecule from each of olefin and amine used. The nucleophilic attack of the aromatic amines IIa,b on olefines Ia-e obeyed Hamett equation

Kinetics of epoxidering opening

The rates of the reactions of some trans -epoxy-p-substituted benzalacetophenones with morpholine in acetonitrile have been measured at different temperatures. The reactions are second order and proceed via S[N2]-like mechanism to give the corresponding alpha-hydroxy-beta -morpholino- beta- [p-substituted phenyl] propiophenones. Effect of substituents has in terms of Hammett linear free energy relationship

Kinetics of addition of aromatic amines on trans-3- [p-substituted phenyl] -1-phenyl prop-2-en-1-ones

The reaction kinetics of a series of traps-3-[p-substituted phenyl]-1-phenyl-prop-2-en-l-ones, 1[a-e], with p-anisidine and p-nitroaniline, were studied in methanol, the reaction rates were measured at 25,30, 35, 40, 45 and 50°C. The reaction has satisfied the second order rate. The calculated activation parameters delta H number sign and delta-s the reactions have led to the suggestion that a multistep mechanism may proceed via amine- Michael addition reaction in which one molecule from each of olefin, and amine may be consumed. Moreover, the obtained results was found to obey Hammett equation

Mass spectrometric studies of some Michael adducts

The reaction products from l-phenyl-3- [p-substituted phenyl]- 2-propenones and ethyl cyanoacetate in slightly or strong basic media have been isolated. Their structures were established as ethyl 2-cyano -5-oxo-5-phenyl-3-[p-substituted phenyl] pentanoates and 2-benzoyl-4-cyano-4-carboethoxy-l -phenyl-3,5 -di[p-substituted phenyl] cyclohexanols, respectively from their mass spectra. The proposed fragmentation patterns are interpreted

Rearrangement of benzylideneacetophenone oxide with sodium phonate in aprotic solvents

Treatment of benzylideneacetophenone oxide [1] with sodium phenoxide in acetonitrile or dioxan gave 2-benzoyl-3, 4 acid type rearrangement. The reaction of III with halogeno acids gave 2, 3, 4, 6-tetraphenyl 1-2 H-pyran-2-carboxylic acid [VI]. The structure of the products was assigned by chemical and spectroscopic methods

Kinetics of aminolysis of some antibacterial vinylic ketones Besicity effect of anilines on aminolysis of trans-1,3-diphenyl prop-2-en-1-one

The addition of para-substituted anilines on 1, 3-diphenyl prop-2-en-1-one in methanol is of the first order in the amine and of the second order in the amine for the reaction in benzene. The reaction in both solvents involves both general-acid and general-base catalysis. The rates of addition in benzene satisfy a similar rate equation for general-base catalysis, where aniline itself acts as a catalyzing base. Pyridine showed catalysis much more strongly than some aromatic amines. Good Hammett correlations with negative beta values of 0.739-1.715 and of 0.599-0.894 for the reactions in methanol and benzene, respectively, were obtained which suggested a cationic character of the transition state. An catalysis-addition reaction of aromatic amine on vinylic ketone [I] proceeding via a multistep mechanism

New aspect of epoxide ring opening

The rates of reactions of some trans-P-substituted epoxy benzalacetophenones with morpholine in acetonitrile have been measured at different temperatures. The reactions are second order and proceeds via SN2 like mechanism to give the corresponding alpha- hydroxy-beta-morpholino-beta-[P-substituted phenyl propiophenones. Effect of substituents has been analyzed in terms of Hammett linear free energy relationship

Kinetics of aminolysis of some antibacterial vinylic ketones II Effect of solvents on aminolysis of trans -3- [p-substituted phenyl] -1- phenyl- prop -2-en -1-one

The reactions of a series of trans-3-[p-substituted phenyl]-1-phenyl- prop-2-en-1-ones Ia-e with p-toluidine and p-nitroaniline IIa, b have been studied in benzene, and their reaction rates were measured. In addition, activation parameters delta H* and delta S* were evaluated, and good Hammett correlation with positive P values of 1.2-1.9, were obtained which suggest the anionic character of the transition state

Additivity of the polar substituent effects in kinetics of aminolysis reaction of some trans-3- [p-substituted phenyl] -1-phenyl-prop-2-En-1-ones

The reaction kinetics of nucleophilic addition of aromatic amines to trans-3-[P-substituted phenyl]-1-phenyl prop-2-en-1-ones were studied as a function of the structural variation in both reactants. The four-parameter of the equation log kg=log ko + pe sigma + r sigma sigma + were used for dual variation which is characterized by the structural constants sigma and sigma +. This equation indicates that the resonance stabilization of the ground and transition state is the main factor that governs the relative reactivities of the nucleophiles

Kinetic studies on Michael Addition Reactions

The kinetic of Michael addition reactions of ethyl cyanoacetate and diethyl malonate to some 1,3-diarly propenones in the presence of sodium ethoxide have been studied in ethanol. The reaction follows third order kinetics and shows a Hammett correlation with positive p values, suggesting a carbanionic character for the transition state. A stepwise rather than a synchronous mechanism could be suggested for this reaction