Synthesis of Zwitterionic Salts of Pyridinium-Meldrum Acid and Barbiturate through Unique Four-component Reactions

摘要

An efficient synthetic procedure for the preparation of the unusual charge-separated pyridinium-Meldrum acid and N,N-dimethylbarbiturate acid zwitterionic salts was developed though a unique one-pot four-component reaction involving pyridine, aromatic aldehyde, Meldrum acid or N,N-dimethylbarbituric acid, and p-nitrobenzyl bromide in acetonitrile. By varying combinations of four components involving nitrogen-containing heterocycles, we conveniently established reactive a-halomethylene compounds, aldehydes and β-dicarbonyl compounds a library of zwitterionic salts.