An Efficient Phosphotungstic Acid Catalysed Synthesis of 4,5‐Dioxopyrrolidines and Study of the Mechanistic Effect of the Solvent on the Reaction

Abstract

An efficient protocol for the synthesis of dioxopyrrolidine scaffolds has been established using phosphotungstic acid as an effective catalyst in a multicomponent reaction of aromatic primary amines, dialkyl acetylene dicarboxylates and formaldehyde at room temperature in alcohol as a green solvent. In this methodology, the reactant solvent has an important part and is involved in the reaction mechanism to increase the versatility of the product. This protocol involves environment friendly, cost effective methodology with a comparatively simple reaction mechanism.

Solvent Screening Is Not Solvent Effect: A Review on the Most Neglected Aspect of Multicomponent Reactions

“…This can be advantageous to modify the properties of the final adduct, but equally the reactivity of the solvent must be considered, should it alter the obtained product from the one that is desired. A similar outcome was also described for an acid‐catalyzed MCR applied for the synthesis of 4,5‐dioxopyrrolidine derivatives [77] . In this example, the nucleophilic character of alcohol solvents was necessary as the reaction does not occur in aprotic solvents.…”

“…A similar outcome was also described for an acid-catalyzed MCR applied for the synthesis of 4,5-dioxopyrrolidine derivatives. [77] In this example, the nucleophilic character of alcohol solvents was necessary as the reaction does not occur in aprotic solvents.…”

HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines

“…An example of HPA is phosphotungstic acid, H 3 PW 12 O 40 (HPW), an inexpensive, non-toxic, and green catalyst with greater chemical and thermal stability in comparison to other heteropolyacids [ 43 ]. HPW has been shown to catalyze MCRs in the synthesis of heterocyclic compounds with high efficiency and chemoselectivity ( Figure 2 ), including functionalized benzo[ c ]chromeno[2,3- a ]phenazine [ 44 ], pyrazolo-fused benzophenazines [ 45 ], 4,5-dioxopyrrolidines [ 46 ], 1,2-dihydropyridine (1,2-DHPs) [ 47 ], pyrimido[4,5- b ]quinoline-tetraones [ 48 ], tetrahydrobenzo[ b ]pyrans and indazolo[2,1- b ]phthalazinetriones [ 49 ]. Herein, we report the synthesis of imidazo[1,2- a ]pyridines via the GBB-3CR using HPW as catalyst in ethanol under microwave (μw) heating.…”

Ultrasound‐promoted novel route to triazabenzo[b]cyclopenta[lm]fluorenes: An efficient NiFe2O4@SiO2–SO3H nanocatalyst‐assisted green synthesis

“…[ 10 ] Acid‐functionalized NPs as solid catalysts have been used a lot nowadays with outstanding catalytic activity for many organic transformations. [ 11 ] The first report on sulfonic acid‐functionalized magnetic NPs used in organic synthesis was done by Gill et al [ 12 ] These modifications result in a better performance in some other chemical transformations. [ 13 ] Moreover, it is a graceful path to bridge between homogeneous and heterogeneous catalysis.…”