An efficient synthesis of neoflavonoid antioxidants based on Montmorillonite K-10 catalysis

A new approach to synthesis of neoflavonoids, based on a high yielding Montmorillonite K-10 catalyzed lactone ring forming cyclization process, is described. The utility of this methodology is exemplified by its employment in the preparation of the substituted 4-phenylneoflavonoids 1-8. The free radical scavenging properties of these substances were evaluated. The neoflavonoids 1 and 5, which mimic esculetin-type antioxidants, were observed to quench hydrazyl free radicals.