A [Et3NH][HSO4]-CATALYZED EFFICIENT, GREEN, AND SOLVENT-FREE SYNTHESIS OF 2,4,6-TRIARYLPYRIDINES

Аннотация

In the present study, we have successfully developed a simple and efficient method for the synthesis of 2,4,6-triarylpyridine derivatives via one-pot three-component condensation reaction of acetophenones, substituted aryl aldehydes, and ammonium acetate, catalyzed by [Et₃NH][HSO₄] as an ionic liquid under solvent-free conditions. The current synthetic route is a green protocol that offers a number of benefits, including a high product yield, mild reaction conditions, reduced chemical waste, shorter reaction time, easy-to-follow operational process, simple catalyst preparation procedure, and the ability to recycle the catalyst up to four times without experiencing a discernible decrease in catalytic activity, as well as a wide range of functional group tolerance and column-free methodology. This ionic liquid is stable toward air and water and is easy to prepare from cheap amine and acid. The protocol works with a wider range of substrates. The current optimization conditions showed that the optimal reaction parameters for the synthesis of 2,4,6-triarylpyridine derivatives in excellent yields are 20 mol % of ionic liquid at 60°C without the use of a solvent.