Abstract

For the first time, we have developed a strategy that provides an access to imidazo[ 1,2-a] pyridines via the cyclization of 2-aminopyridine with mucobromic acid as C₃ synthon. In the combination with theoretical calculation, the reaction mechanism is proposed.

Background: 2-Aminopyridines are the typical pyridine α-site derivatives, which have received growing interest in using as a kind of synthons in organic synthesis and drug synthesis because of their special binucleophilic framework.

Methods: All these obtained compounds were characterized by NMR. Among them, 3a was characterized by single-crystal X-ray analysis. All the theoretical calculation works were performed by Gaussian software.

Results: A series of the desired compounds can be synthesized at room temperature via a mild procedure under the promotion of simple inorganic base K₂CO₃.

Conclusion: This mild strategy fits the concept of green chemistry, providing a novel idea for the construction of nitrogen-containing polyheterocyclic compounds.

Keywords: Imidazo[1, 2-a]pyridines, 2-aminopyridines, mucobromic acid, cyclization, binucleophile, green synthesis.