Straightforward Synthesis of Various 2,3‐Diarylimidazo[1,2‐a]pyridines in PEG₄₀₀ Medium through One‐Pot Condensation and C–H Arylation

Abstract

PEG400 is described herein as a suitable medium for the condensation of various 2‐amino pyridines with α‐bromo ketones. 2‐Arylimidazo[1,2‐a]pyridines were synthetized in a short time through microwave irradiation in moderate to excellent yields. After optimization, a convenient one‐pot process enabled access to 2,3‐diarylimidazo[1,2‐a]pyridines by using a reduced amount of palladium catalyst without ligand for the C–H arylation step in the same environmentally‐sound medium.

New Series of Thiazole Derivatives: Synthesis, Structural Elucidation, Antimicrobial Activity, Molecular Modeling and MOE Docking

“…1 H-NMR of the isolated product showed a remarkable singlet at δ = 8.20 ppm for the imidazole proton. The high value of such a chemical shift indicated that this =CH is adjacent to a sp 3 hybridized nitrogen atom [26,27], which is possible in isomer 6A rather than isomer 6B . As illustrated in Scheme 2, the reaction proceeds via the formation of an iminothiadiazole intermediate I , followed by in-situ dehydrative cyclization to form the desired fused heterocycle 6A [19].…”

Greener Synthesis of Nitrogen-Containing Heterocycles in Water, PEG, and Bio-Based Solvents

“…In 2014, Berteina-Raboin et al generated 2-arylimidazo[1,2-a]pyridines in good yields within 10 minutes from readily available 2-amino pyridines and α-bromo ketones. A one-pot procedure was engineered to achieve 2,3-diarylimidazo[1,2-a]pyridines using a reduced amount of palladium catalyst without ligand for the C-H arylation step in the same environmentally sound medium (Scheme 52) [96]. In 2014, Berteina-Raboin et al, generated 2-arylimidazo[1,2-a]pyridines in good yields within 10 minutes from readily available 2-amino pyridines and α-bromo ketones.…”

Eucalyptol as a Bio-Based Solvent for Buchwald-Hartwig Reaction on O,S,N-Heterocycles

“…Pursuing our objective of the development of new practices in the synthesis of heterocycles containing oxygen, sulfur and nitrogen, [3][4][5][6][7][8] we explored the potentialities of eucalyptol as a solvent in the Buchwald-Hartwig coupling reaction. This work began with a literature review to identify the best conditions for this kind of transformation.…”