DABCO catalyzed rapid one-pot synthesis of 1,4-dihydropyrano [2,3-c] pyrazole derivatives in aqueous media

A simple and efficient protocol is developed for the synthesis of dihydropyrano[2,3-c]pyrazole derivatives by a one pot, four component reaction of ethylacetoacetate, hydrazine hydrate, malanonitrile and various aldehydes in the presence of a catalytic amount of DABCO in aqueous medium. This method provides several advantages such as high yield, shorter reaction time, mild reaction condition, operational simplicity, easy work-up procedure with environment friendly nature and purification of products by non-chromatographic methods has been developed.