Organocatalytic Green Approach Towards the Fabrication of Fused Benzo N,N‐containing Heterocycles Facilitated by Ultrasonic Irradiation

Abstract

The development of a metal‐free protocol for transformations in organic synthesis offers a significant potential environmental benefit. This article reports the exploration of meglumine, a nontoxic and biodegradable amino sugar, as an organocatalyst for the synthesis of biologically active 1H‐dibenzo[b,e][1,4]diazepin‐1‐ones, highly regioselective benzimidazole derivatives and derivatives of quinoxalines. Operational simplicity, mild reaction conditions, shorter reaction times, and use of green solvents are the highlights of this protocol. The advantage of ultrasonic irradiation has been significantly explored for the synthesis of the aforesaid compounds. Furthermore, the multifaceted use of o‐phenylenediamine has also been accentuated in the study.

A redox active organodiselenide as an efficacious catalyst for the synthesis of oxygen-containing heterocyclic compounds

“…As a continuation of our previous research 37–42 on the development of green synthetic methodologies for multicomponent reactions, we report herein a synthetic approach towards a three-component reaction comprising of aryl aldehydes, malononitrile and dimedone/1,3-cyclohexanedione that is carried out in a water–ethanol (3 : 1) medium. The reaction was facilitated by ultrasound in the presence of DSePA as a catalyst (Scheme 1).…”

Synthesis of Imidazole-Based Molecules under Ultrasonic Irradiation Approaches

“…In 2019, Nongrum and her co-workers, with ultrasonic assistance, brought about a green approach toward the fabrication of benzimidazole scaffolds 56 ( Scheme 40 ) [ 83 ]. These researchers used meglumine as the green and harmless catalyst for the Phillips–Ladenburg reaction.…”

Ultrasound-assisted transition-metal-free catalysis: a sustainable route towards the synthesis of bioactive heterocycles

“…Nongkhlaw et al in 2019 pioneered the use of meglumine as a biodegradable organocatalyst in association with the application of sonochemical activation for the production of various quinoxaline derivatives 123 ( Scheme 34 ). 164 Initial optimization of the appropriate amount of the catalytic system and reaction medium for the reaction of 1,2-diamine 121 with 1,2-diketone 122 revealed that only 8 mol% of the catalyst was sufficient for catalyzing this reaction and aqueous ethanol was found to be the best solvent under sonication as well as under conventional heating conditions. However, the reaction requires much more time under traditional heating conditions, and the desired quinoxaline products have been achieved in low yield in contrast to the reaction executed under ultrasound irradiation.…”