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Updated: Sep 24, 2025

Microwave-Assisted Preparation of 1-Aryl-1H-pyrazole-5-amines
Published on: June 23, 2019
Facile synthesis of 3-substituted imidazo[1,2-a]pyridines through formimidamide chemistry
Rasapalli Sivappa1, Vamshikrishna Reddy Sammeta1, Yanchang Huang1
1Department of Chemistry and Biochemistry, University of Massachusetts 287 Old Westport Rd, North Dartmouth MA-02747 USA srasapalli@umassd.edu.
Abstract:
A facile entry to 3-aryl/alkenyl/alkynyl substituted imidazo[1,2-a]pyridines (3a-p, 6a-d & 9a-9e) has been developed from readily available benzyl/allyl/propargyl halides and 2-amino pyridines as substrates via formimidamide chemistry that is devoid of caustic or expensive reagents, such as transition metal complexes. Quantum chemical calculations performed to understand the underlying mechanism of the transformation revealed a preference for intramolecular Mannich-type addition over pericyclic 1,5-electrocyclization for the systems reported herein that enable a Baldwin allowed 5-exo-trig cyclization instead of a formally anti-Baldwin 5-endo-trig process.
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