An experimental investigation of substituent effects on the formation of 2,3-dihydroquinazolin-4(1H)-ones: a kinetic study

Abstract

The effect of different substituents on the kinetics of the reactions between 2‐amino‐benzamide and some of benzaldehyde derivatives have been spectrally investigated in the presence of formic acid. The proposed mechanism were challenged due to the determination of rate‐determining step (RDS) and also, to obtain the general rate law of the reaction. For all substituents, the reactions followed the second‐order kinetics and the partial orders of reactions were recognized with respect to each reactant. Electron withdrawing substituents on benzaldehyde ring increased the rate of reaction. Kinetic values (k and Ea) and associated activation parameters (ΔH‡, ΔG‡ and ΔS‡) of the reactions were determined. Both the Arrhenius and the Eyring equations were used to calculate activation energy. Comparison of magnitude of and T showed that the reactions were enthalpy controlled. Isokinetic plots for the reactions were plotted and linear relationship between and recognized that relative contribution of enthalpy and entropy to the overall free energy was the same in the reactions.

A Water/Toluene Biphasic Medium Improves Yields and Deuterium Incorporation into Alcohols in the Transfer Hydrogenation of Aldehydes

“…In the same work, it was observed that the o ‐MeO benzaldehyde (II‐OMe ) was reduced faster than its para ‐substituted counterpart. Similar effects of electron‐withdrawing groups on nucleophilic reactions involving benzaldehydes have been previously described [64] . By contrast, Ogo et al [65,66] .…”

“…Similar effects of electron-withdrawing groups on nucleophilic reactions involving benzalde-hydes have been previously described. [64] By contrast, Ogo et al [65,66] concluded that steric and electronic effects exert a negligible influence in TH of ketones catalyzed by [(η 6 -C 6 Me 6 ) Ru(bpy)(H)] + and [Cp*Ir(bpy)(H)] + at pH 4.0 and 2.0, respectively.…”

Synthesis and evaluation of the antioxidant activity of 3-pyrroline-2-ones: experimental and theoretical insights

“…63 Consequently, the rate of imine formation reaction between 4-nitrobenzaldehyde ( 1c ) and aniline ( 2a ) is faster than that between 4-methylbenzaldehyde ( 1b ) and aniline ( 2a ). 64 The easier the imine formation, the higher the yield of desired product polysubstituted 3-hydroxy-1,5-dihydro-2 H -pyrrol-2-one. Moreover, the formation of the –CHN– double bond will decrease when using aliphatic amines as compared to aromatic amines.…”

Kinetics and related studies of the formation of 2,3‐dihydroquinazolin‐4(1H)‐ones in the presence of different benzaldehyde derivatives

“…These unique biological properties have made quinazolinone synthetic studies over the years very attractive . It is notable that the kinetics and synthesis studies have been reported for these reactions . Herein, we investigate the validity of the isokinetic relationship and compensation effect in addition to the kinetic studies.…”

“…In order to study the nature of the reaction mechanism, it is important to study the effect of different factors on the rate of the reaction and determine the various kinetic and activation parameters. The isokinetic relationship is helpful in determining whether a series of reactions are following same mechanism . A number of methods have been developed to obtain experimental kinetic data and analyze them to arrive at a true explanation of the reaction mechanism.…”