A simple synthesis of trifluoromethylated pyridinium azomethine ylides by three-component reaction between pyridines, phenacyl bromides, and N-aryltrifluoroacetimidoyl chlorides

Abstract

A novel synthesis of trifluoromethylated pyridinium azomethine ylides by three-component reaction between pyridines, phenacyl bromides, and trifluoromethylated imidoyl chlorides in acetonitrile as solvent at room temperature without any catalyst is described. The FT-IR, 1H, 13C, 19F NMR spectral and elemental analysis confirm the structures of products. The synthesized azomethine ylides are easily purified by washing with diethyl ether and are stable even at high temperature. Heating of these ylides in refluxing acetonitrile, ethanol, or DMSO did not result in the intramolecular cyclization to imidazopyridine derivatives and only starting ylides were isolated.