A Facile and Catalyst-Free Microwave-Promoted Multicomponent Reaction for the Synthesis of Functionalised 1,4-Dihydropyridines With Superb Selectivity and Yields.

Nagaraju Kerru,Sreekantha B Jonnalagadda,Suresh Maddila

doi:10.3389/fchem.2021.638832

Nagaraju Kerru, Sreekantha B Jonnalagadda + Show 1 more

Open Access

https://doi.org/10.3389/fchem.2021.638832

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Abstract

We report a highly efficient green protocol for developing a novel library of 1,2,4-triazole-tagged 1,4-dihydropyridine analogs through the one-pot process from the four-component fusion of the 1H-1,2,4-triazol-3-amine with different chosen aldehydes, diethyl acetylenedicarboxylate, and active methylene compounds in a water medium under microwave irradiation and catalyst-free conditions. Excellent yields (94–97%) of the target products were achieved with high selectivity with a short reaction time (<12 min) at room temperature. The structures of the synthesized pyrimidine analogs were established by NMR and HRMS spectroscopic analysis. Simple workup, impressive yields, no column chromatography, green solvent, rapid reaction, and excellent functional group tolerance are the benefits of this protocol.

Highlights

The green chemistry approach employing non-hazardous chemicals and eco-friendly reaction conditions is most motivating in preparing broadly used and pharmacologically significant organic compounds (Kerru et al, 2019a,b)
We report a highly efficient green protocol for developing a novel library of 1,2,4-triazole-tagged 1,4-dihydropyridine analogs through the one-pot process from the four-component fusion of the 1H-1,2,4-triazol-3-amine with different chosen aldehydes, diethyl acetylenedicarboxylate, and active methylene compounds in a water medium under microwave irradiation and catalyst-free conditions
The microwave irradiation (MW) technique has attracted considerable interest in organic synthesis due to the higher selectivity, improved product yield, and atom economy, which reduce the by-product generation compared to conventional thermal heating techniques (Khumalo et al, 2019)

Summary

Introduction

The green chemistry approach employing non-hazardous chemicals and eco-friendly reaction conditions is most motivating in preparing broadly used and pharmacologically significant organic compounds (Kerru et al, 2019a,b). The microwave irradiation (MW) technique mostly applies environmentally benign green technology in heating to speed up the organic reactions for value-added conversions. The MW-assisted organic synthesis has become a powerful tool and an excellent non-conventional approach in the green synthetic methodologies in modern drug discovery programs (Wathey et al, 2002; Mavandadi and Pilotti, 2006). The MW technique has attracted considerable interest in organic synthesis due to the higher selectivity, improved product yield, and atom economy, which reduce the by-product generation compared to conventional thermal heating techniques (Khumalo et al, 2019). MW-mediated organic synthesis is the preferred green method over unconventional to classical thermal processes for the rapid synthesis of a series

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