One-Pot Eco-Safe Saccharin-Catalyzed Procedure for Expedient and Convenient Synthesis of Dihydropyrano[2,3-<i>c</i>]pyrazole, Tetrahydrobenzo[<i>b</i>]pyran and Pyrano[2,3-<i>d</i>]pyrimidinone Scaffolds as a Green and Versatile Catalyst

Abstract

A green and facile saccharin-catalyzed procedure is developed for the one-pot convenient synthesis of dihydropyrano[2,3-c]pyrazole, tetrahydrobenzo[b]pyran and pyrano[2,3-d]pyrimidinone scaffolds via multi-component tandem Knoevenagel cyclocondensation reaction. This procedure has the chief advantages of green, inexpensive and readily available catalyst, high atom-economy, high to quantitative yields and the reaction procedure is mild and involves facile workup procedure to obtain the desired products in short reaction times.

Keywords

• green procedures
• saccharin
• dihydropyrano[2,3-c]pyrazoles
• tetrahydrobenzo[b]pyrans
• pyrano[2,3-d]pyrimidinones