s Cyclization of 2-Aminopyridines as Binucleophile and Mucobromic Acid as C3 Synthon: A New Access to Imidazo[1,2-a]Pyridines

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.