Synthesis of flavanones, azaflavanones, and thioflavanones catalyzed by PMA-SiO 2 as a mild, efficient, and reusable catalyst

Abstract

Cyclization of a variety of chalcones to flavanones catalyzed by 1 mol% phosphomolybdic acid (PMA) supported on silica as a mild, efficient, and reusable catalyst was carried out in high yields. PMA-SiO 2 is an efficient, inexpensive, and green catalyst which gave high conversion yields and could be recycled up to three times without significant loss in activity. © Springer-Verlag 2011.