Theoretical, Kinetic and Mechanistic Studies of the Reaction between Dialkyl Acetylenedicarboxylates, Triphenylphosphine and Pyrrole in Organic Solvents

Abstract

The kinetics of the reaction between triphenylphosphine, dialkyl acetylenedicarboxylates and pyrrole in dry organic solvents at different temperatures have been studied spectrophotometrically. The observed overall second rate constant (k 2 ) for reaction decreases with decreasing solvent dielectric constant and media temperature; k 2 follows the Arrhenius equation, and the overall reaction is first order in both the dialkyl acetylenedicarboxylate and triphenylphosphine concentrations. The proposed mechanism has been evaluated, and the activation parameters DG 6 ¼ , DS 6 ¼ and DH 6 ¼ for the first, rate-determining step, as an elementary reaction have been determined on the basis of Eyring equation. In addition, the Z-and E-isomers have been optimized at HF and B3LYP levels with the 6-311þþG** basis set; the more stable is the E-isomer, in agreement with experimental data. Furthermore, to better understand the intramolecular interactions, atoms in molecules (AIM) calculations and natural population analysis (NPA) methods have been carried out. The 1 H, 13 C, and 31 P NMR data of these ylides are consistent with results obtained from theoretical calculations.

A Mechanistic Investigation of Stable Phosphonate Ester Derived from 3, 4 dichloro Aniline: A Kinetics Study and Theoretical Calculations

“…In fact, in recent works triphenyl phosphite has been used instead of triphenylphosphine in the previous work. [33][34][35][36][37][38][39][40][41] In addition, the product is phosphonate esters 4 not phosphorus ylides. Synthesis of compounds 4, shown in Figure 1, has been reported earlier.…”

Kinetic and Mechanistic Investigation of Pyrano[2,3-d]pyrimidine Formation in the Presence of Catalyst under Novel One-Pot Three-Component Reaction

“…Moreover, the overall reaction order followed second-order kinetics. The rate of all reactions was increased in solvents with upper dielectric constant value that could be related to the differences in stabilization of the reactants and the zwitterionic intermediate by the solvents [29][30][31][32][33][34][35][36]. In present work, we describe kinetic results together with detailed mechanistic studies for the one-pot, three-component condensation reactions consisting of 4-nitrobenzaldehyde 2, malononitrile 3, and thiobarbituric acid 1 in the presence of sodium acetate as a catalystin methanol and environmental friendless solvents (mixture of ethanol and H 2 O 50/50) based on a global kinetic analysis methodology using the UV-vis spectrophotometry apparatus.…”

“…Step 5 Utilizing the above results, the simplified scheme of the proposed reaction mechanism (Scheme 2, [29][30][31]) as a possible explanation is shown in Figure 6 [14,18,37].…”

“…Kinetics and mechanism of numerous reactions have been previously studied using the UV-vis technique [24][25][26][27][28]. In recent years, we have endeavored to expand the synthesis of phosphorous ylides along with developing experimental and theoretical studies on the kinetics and mechanisms of these reactions [29][30][31][32][33][34][35][36]. In these studies, reactions occurred by at least three steps.…”

Insights into the Reaction Mechanism of the Tetrahydrobenzo [b] pyran by means of Kinetic Studies in the Presence of Fructose as a Green Catalyst

“…As part of our ongoing pursuit for the kinetics and mechanistic investigations of various reactions [46][47][48][49][50][51][52][53][54][55][56][57][58] , we herein investigated the kinetic and mechanism of multicomponent reaction between 4-methoxybenzaldehyde (1), malononitrile (2), and dimedone (3) in the presence of fructose as a catalyst in a mixture of water and ethanol. Synthesis of substituted tetrahydropyridines has been previously reported by N. Hazeri and et al 59 .…”