Structural effects on kinetics and a mechanistic investigation of the reaction between DMAD and N–H heterocyclic compound in the presence of triphenylarsine: spectrophotometry approach

Abstract

Kinetics and a mechanistic investigation of the reaction between dimethyl acetylenedicarboxcylate (DMAD) and saccharin (N–H heterocyclic compound) has been spectrally studied in methanol environment in the presence of triphenylarsine (TPA) as a catalyst. Previously, in a similar reaction, triphenylphosphine (TTP) (instead of triphenylarsine) has been employed as a third reactant (not catalyst) for the generation of an ylide (final product) while, in the present work the titled reaction in the presence of TPA leaded to the especial N-vinyl heterocyclic compound with different kinetics and mechanism. The reaction followed second order kinetics. In the kinetic study, activation energy and parameters (Ea, ΔH‡, ΔS‡ and ΔG‡) were determined. Also, the structural effect of the N–H heterocyclic compound was investigated on the reaction rate. The result showed that reaction rate increases in the presence of isatin (N–H compound) that participates in the second step (step2), compared to saccharin (another N–H compound). This was a good demonstration for the second step (step2) of the reaction that could be considered as the rate- determining step (RDS). As a significant result, not only a change in the structure of the reactant (TPA instead of TPP) creates a different product, but also kinetics and the reaction mechanism have been changed.

Copper(II) Prevents the Saccarine-Dialkylcyanamide Coupling by Forming Mononuclear (Saccharinate)(Dialkylcyanamide)copper(II) Complexes

“…Our recent finding in the saccharin chemistry was the observation of unusual metalfree "two saccharin-one cyanamide" coupling between sacH and NCNR 2 to grant guanidinated saccharin derivatives [8]. The distinctive feature of this transformation is its formal three-component character, while other known examples of reactivity of sacH toward multiple bond substrates includes the additions to amino alkynes [9,10], isocyanide [11], isocyanates [12], and carbodiimides [12,13]; all these examples include two-component 1:1 additions.…”

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).…”