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

Abstract

Sodium acetate was applied as an efficient catalyst for the one-pot, three-component condensation reactions consisting of 4-nitrobenzaldehyde 2, malononitrile 3, and thiobarbituric acid 1. Use of nontoxic reaction components, short reaction times, environmental, easy work-up, and high yields are some remarkable advantages of this method. Kinetics and mechanism of the reaction were spectrally studied and the second order rate constant (k ovr = k 1 ) was automatically calculated by the standard equations contained within the program. The second order rate constant [Ln(k ovr = k 1 ), Ln(k ovr = k 1 )/T] that depended on reciprocal temperature was in good agreement with the Arrhenius and Eyring equations, respectively. This data provided the suitable plots for calculating the activation energy and parameters (Ea, ΔG ‡ , ΔS ‡ , and ΔH ‡ ) of the reaction. Furthermore, from studying the effects of solvent, concentration, and catalyst on the reaction rate, useful information was obtained regarding the mechanism. The results showed that the first step of the reaction mechanism is a rate determining step (RDS). The proposed mechanism was confirmed in accordance with the experimental data and also the steady state approximation.

Importance of Hybrid Catalysts toward the Synthesis of 5H-Pyrano[2,3-d]pyrimidine-2-ones/2,4-diones (Thiones)

“…The same reaction conditions was utilized by Habibi-Khorassani et al 132 This group of co-workers reported kinetic and mechanistic studies on the one-pot synthesis of 7-amino-5-(4-nitrophenyl)-4-oxo-2-thioxo-1,3,4,5-tetrahydro-2 H -pyrano[2,3- d ]-pyrimidine-6-carbonitrile 91 ( Scheme 66 ). They used equimolar (1 mmol) reaction of 1 with 12 and 11 in sodium acetate with aqueous ethanol at 50 °C.…”

Effect of Reactivity on Kinetics and a Mechanistic Investigation of the Reaction between Dimethyl Acetylenedicarboxylate and 1,3-Dicarbonyl Compounds in the Presence of a Catalyst: A Spectrophotometric Approach

“…Thus, arsonium ylides react frequently in the form of ylide B ( Figure 2) faster than phosphonium ylides. Although the kinetics and mechanistic investigations of some reactions with TPP have been reported previously [6][7][8][29][30][31][32][33], no attempts for similar reactions with TPA have been reported. www.prkm.co.uk…”

A Study on the Kinetics and Mechanism of the One-Pot Formation of 3,4,5-Substituted Furan-2(5H)-Ones in the Presence of Lactic Acid: Effect of Different Substituents

“…Lactic acid (HL) is considered as a top 12 biobased platform molecule and may serve as a useful precursor chemical for producing green solvents and polymers [36,37] with wide usage in pharmaceuticals, cosmetics and food packaging [38,39]. In continuation of our ongoing programme in the kinetics of multi-component reactions [40][41][42][43][44][45][46][47][48][49][50], here we investigated the kinetics and mechanism of the reactions between para-substituted anilines 1 and dimethyl acetylenedicarboxylate (DMAD) (2) with benzaldehyde derivatives 3 for the formation of 3,4,5-substituted furan-2(5H)-ones using HL as an efficient catalyst in ethanol at ambient temperature, with good yields. Synthetic details of this reaction have been published earlier by Maghsoodlou and co-workers [51] (see Figure 1).…”