Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects

Abstract

Microwave-assisted (MWA) multicomponent reactions (MCRs) have successfully emerged as one of the useful tools in the synthesis of biologically relevant heterocycles. These reactions are strategically employed for the generation of a variety of heterocycles along with multiple point diversifications. Over the last few decades classical MCRs such as Ugi, Biginelli, etc. have witnessed enhanced yield and efficiency with microwave assistance. The highlights of MWA-MCRs are high yields, reduced reaction time, selectivity, atom economy and simpler purification techniques, such an approach can accelerate the drug discovery process. The present review focuses on the recent advances in MWA-MCRs and their mechanistic insights over the past decade and shed light on its advantage over the conventional approach.

Design of Anti-infectious Agents from Lawsone in a Three-Component Reaction with Aldehydes and Isocyanides

“…Microwave-assisted organic synthesis has attracted great attention in the last decades and has proven to be particularly useful in the construction of important heterocyclic systems such as benzothiazoles and benzoxazoles . Microwave-assisted multicomponent reactions are also part of this progress, having been emerged as useful tools for the elaboration of relevant heterocycles …”

“… 38 Microwave-assisted multicomponent reactions are also part of this progress, having been emerged as useful tools for the elaboration of relevant heterocycles. 39 …”

“…38 Microwaveassisted multicomponent reactions are also part of this progress, having been emerged as useful tools for the elaboration of relevant heterocycles. 39 The reaction was first conducted in the presence of solvents (toluene and 1,2-dichloroethane DCE) and catalysts (Et 3 N and EDDA), favoring the Knoevenagel condensation. All reactions were conducted under reflux for 2 h and monitored by thin-layer chromatography (TLC) every 30 min.…”

Polymer Processing under Microwaves

“…It is therefore possible to heat preferentially some regions or some reactants within the sample, while other regions present lower temperatures. This property can be usefully operated in the case of some reactional systems, fostering regio-, chemio-, and stereo-selectivity [21][22][23] or during the heating of composites [5].…”

Diastereoselective multicomponent synthesis of dihydroisoindolo[2,1-a]quinolin-11-ones mediated by eutectic solvents

“…This synthetic methodology, in combination with the use of heterogeneous and easily recoverable catalysts, alternative solvents and microwave irradiation, has promoted the preparation of interesting compounds with broad applications in medicinal chemistry. [10][11][12] Among the known multicomponent reactions, the inverse electron-demand aza Diels-Alder approach (IEDDA reaction) has been of great interest for synthetic chemists because this synthetic tool allows the obtention of quinoline derivatives highly functionalized considering the wide variety of functional groups that can be attached to the aromatic amine, the aldehyde and the dienophile. Recently, numerous efforts in the IEDDA reaction directed toward the preparation of asymmetric derivatives [13][14][15][16][17] and ring-fused derivatives have been reported.…”