Abstract
Piperazine supported on amorphous silica (KG-60-piperazine) as a basic catalyst acts in the Gewald three-component reaction of some aldehydes and ketones with malononitrile as well as ethyl cyanoacetate. The catalyst shows general utility with a variety of starting carbonyl compounds. Moreover, the catalyst can be reused for four additional cycles without significant loss of the activity.
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GRAPHICAL ABSTRACT
Notes
a Reaction conditions: time = 4 h, temperature = 80 °C, catalyst = 10 mol%, compound 2 = 20 mmol, compound 3 = 20 mmol.
b Isolated yields. All the products gave satisfactory 1H NMR and IR spectra.