Tandem Synthesis of ۲,۳,۴,۵-Tetrasubstituted Pyrroles from Aromatic Aldehydes Using Diethylene Glycol-bis(۳-methylimidazolium) Dihydroxide as an Efficient Catalyst

A sequential process strategy was introduced for the synthesis of ۲,۳,۴,۵-tetrasubstituted pyrroles by the formation of benzoin from the corresponding aromatic aldehyde and followed by condensation reaction with ۱,۳-dicarbonyl compounds and ammonium acetate in the presence of diethylene glycol-bis(۳-methylimidazolium) dihydroxide as catalyst in refluxing ethanol. The recycled catalyst could be reused four times without appreciable loss in the catalytic activity.