Synthesis of Arylidene (thio)barbituric Acid Derivatives using Bentonite as a Natural and Reusable Catalyst in Green Media

Known as a Lewis acid which acts as a natural catalyst, bentonite can be used to produce several arylidene  (thio) barbituric  acid  derivatives  through  conducting  a  Knoevenagel  reaction  between aromatic aldehydes and (thio) barbituric acid. Water is considered as the medium for this reaction and the results are at arange of good to excellent over a reasonable reaction time. This method is natural and economic as well as convenient to work with, while the reaction time is also short. In addition  to excellent  results,  this  method  is  also environment-friendly  due  to  the  use  of  water  as solvent that broadens the domain of organic synthesis in aqueous medium.