Greener synthetic approach for the preparation of substituted flexible dimeric pyridinium salts and its importance

We have prepared substituted flexible dimeric pyridinium bromide using conventional and greener approach. Solvent-free solid phase (greener) approach is superior than the conventional owing to nontoxic, easy workup procedure, and 20 times lesser reaction time. Toxic organic solvents and column chromatography are avoided. Aldol condensation reaction is studied with various substituted aromatic aldehyde and compared with available recent literatures. Synthesized substituted flexible dimeric pyridinium salts acted as potential catalysts because of their better performance even in low concentration, recyclability, and activation of two molecules of aldehydes at the same time for aldol condensation reaction.