Brønsted acid-catalyzed regioselective ring opening of 2H-azirines by 2-mercaptopyridines and related heterocycles; one pot access to imidazo[1,2-a]pyridines and imidazo[2,1-b]thiazoles

• Published in: Organic & biomolecular chemistry Vol. 22; no. 23; pp. 4697 - 4703
• Main Authors: Biswas, Subrata, Roy, Arnab, Duari, Surajit, Maity, Srabani, Elsharif, Asma M., Biswas, Srijit
• Format: Journal Article
• Language: English
• Published: CAMBRIDGE Royal Soc Chemistry 2024; Royal Society of Chemistry
• Subjects: Catalysis; Chemical synthesis; Chemistry; Chemistry, Organic; Physical Sciences; Pyridines; Regioselectivity; Ring opening; Science & Technology; Thiazoles; Thiols; FORMAL 3+2 CYCLOADDITION; ANTITUMOR EVALUATION; CELLS; IN-VITRO; NUCLEOPHILIC-SUBSTITUTION; AZACYCLOPROPENE; PYRROLE SYNTHESIS; GUANYLHYDRAZONES; BOND-CLEAVAGE; DERIVATIVES
• ISSN: 1477-0520; 1477-0539
• DOI: 10.1039/d4ob00410h

A catalytic and versatile synthetic method for the synthesis of imidazo[1,2-a]pyridines has been developed. Br & oslash;nsted acid-catalysis plays a major role in the regioselective ring opening of 2H-azirines. Nucleophilic attack via the N-centre of mercaptopyridines and their analogues, followed by cyclisation by cleaving the C-S bond, allowed a library of imidazo[1,2-a]pyridines and related heterocycles to be built. The reaction protocol has been applied to various 2H-azirines, 2-mercaptopyridines, and thiazole-2-thiols, illustrating the generality of reaction conditions. The practical applications include the synthesis of pharmaceuticals, such as anti-tumor agents. This study introduces a novel approach to the synthesis of functional molecules with extensive potential.