TiO2–SiO2 Catalyzed Eco‐friendly Synthesis and Antioxidant Activity of Benzopyrano[2,3‐d]pyrimidine Derivatives

A cost‐effective and eco‐friendly synthesis of benzopyrano2,3‐d ]pyrimidine derivatives has been developed via three component one‐pot tandem approach by condensing different salicylaldehydes and secondary amines with malononitrile in the presence of TiO₂–SiO₂ catalyst at 80°C under solvent‐free conditions. Mild experimental conditions, reusability of the catalyst, and cost effectiveness are the merits of this procedure. Compounds 4g , 4h , and 4i bearing 2‐OMe group on the hydroxyphenyl group linked to the central carbon present in between the two nitrogen atoms of the pyrimidine ring were found to exhibit good antioxidant activity while other compounds have moderate antioxidant activity.