Biologically Active Benzoxazolinone in Reaction with Triphenylphosphine, Dialkyl Acetylenedicarboxilates and Theoretical Study on the Kinetic and Mechanism Investigation of the Reactions
S.M. Habibi-Khorassani*, A. Ebrahimi, M. T. Maghsoodlou and M. A. Kazemian

Department of Chemistry, University of Sistan and Baluchestan.

Abstract: The major objectives of the work undertaken were to carry out kinetic studies of the reaction between triphenylphosphine, dialkyl acetylenedicarboxylates in the presence of NH-acid, such as benzoxazoline. To determine the kinetic parameters of the reaction, it was monitored by UV spectrophotometery. The second order fits were automatically drawn and the values of the second order rate constant (k2) were calculated using standard equations within the program. At the temperature range studied the dependence of the second order rate constant (ln k2) on reciprocal temperature was in a good agreement with Arrhenius equation. This provided the relevant plots to calculate the activation energy of all reactions. Furthermore, useful information were obtained from studies of the effect of solvent, structure of reactants (different alkyl groups within the dialkyl acetylenedicarboxylates and NH-acids) and also concentration of reactants on the rate of reactions. Proposed mechanism was confirmed according to the obtained results and steady state approximation and first step (k2) of reaction was recognized as a rate determining step on the basis of experimental data. In addition, assignment of more stabe isomers (Z or E) was investigated using the AIM theory.

Keywords: Triphenylphosphine; UV spectrophotometry; Kinetic parameters; Geometrical isome

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