Ecofriendly synthesis of pyrano[2,3-d]pyrimidine derivatives and related heterocycles with anti-inflammatory activities.

A versatile, efficient, clean, and facile method was used for the synthesis of pyrano[2,3-d]pyrimidine derivatives by the one-pot three-component condensation reaction of thiobarbituric acid and malononitrile with p-chlorobenzaldehyde, using Fe O or ZnO or Mn O as nanostructure catalysts. The catalyst could be easily recovered using an external magnet and reused for six cycles with almost a consistent activity. A series of polyheterocyclic compounds containing five and/or six rings fused with each other was designed.