One-pot Synthesis of 1,4 Dihydro Pyrano [2, 3-c] Pyrazole using Chitosan-p-toluene Sulfonate as a Biodegradable Catalyst in an Aqueous Medium

A rapid and facile one-pot three-component synthesis of biologically active 6-amino-5- cyano-4-aryl-1,4-dihydro pyrano[2,3-c] pyrazoles was developed using chitosan-p-toluene sulfonate (CS-p-TSA) as a biodegradable catalyst in an aqueous medium. The products synthesized were characterized by FT-IR, 1H-NMR, and 13C NMR. The catalyst was stable and could be used for five cycles without much change in the catalytic activity. The products synthesized were in good yields (90-96%). This method provides several advantages, including the use of a biodegradable catalyst, a simple workup procedure, mild reaction conditions, and lower reaction times.