Efficient synthesis of dihydrochromeno-[4,3-b]chromenone derivatives in aqueous media

Abstract

Dihydrochromeno[4,3-b]chromenone derivatives were synthesized successfully via a pseudo three-component reaction of salicylaldehyde derivatives with 4-hydroxycoumarin in a ratio of 1:2 respectively in aqueous media catalyzed by diammonium hydrogen phosphate (DAHP) or S-proline at room temperature. This later modified by a solvent-free approach without catalyst at 80°C. These are the first reports on the synthesis of dihydrochromeno[4,3-b]chromenones by these procedures. The application of these methods to corresponding products are highlighted that can be adopted for simple operation, easy work-up, high yields, high-speed (specially under solvent-free approach) and environmentally benign procedure.