The micellar catalysis is well-known for its hydrophobic effect that is the tendency of nonpolar
groups to cluster within the lipophilic core so as to shield them from contact with an aqueous environment
formed upon the dissolution of a surfactant in water. This provides a unique opportunity to
establish organic transformations in greener solvents, such as water leading to organic waste control
and easy product isolation protocols. Considering the significant interaction of thiobarbituric acid moieties
in a biological macromolecule core, herein, a highly efficient procedure for the synthesis of biological
and medicinal important 5-(arylmethylene)dihydro-2-thioxo-4,6(1H,5H)-pyrimidinediones via
Knoevenagel condensation of thiobarbituric acids and aldehydes catalyzed by a surfactant, sodium dodecyl
sulfate, is developed. The synthetic procedure shows the excellent activity of the micellar catalysts
towards the aldehyde activation leading to a facile condensation. The application of the method
is demonstrated by further synthesis of 5,5'-(4-arylmethylene)bis[dihydro-2-thioxo-4,6(1H,5H)-
pyrimidinediones]. Theoretical studies of the reaction were also carried out to investigate the effect of
electron releasing and electron-withdrawing group in benzaldehyde on the reaction.
Keywords: Green catalysis, Knoevenagel condensation, pseudo-domino reaction, recyclability, surfactant catalyst.
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