Tandem Protocol for the Synthesis of Pyrano[3,2-c]quinolone Derivatives Using Taurine as a Green Bio-Organic Catalyst in Aqueous Medium

A series of pyrano[3,2-c]quinolone derivatives has been synthesized in the presence of taurine (2-aminoethanesulfonic acid) as a green bio-organic catalyst and water as the solvent. The target compounds were synthesized through the three-component reaction between aldehydes, malononitrile/ethylcyanoacetate, and 4-hydroxy-1-methyl-2(1H)-quinolone. The advantages of this protocol are excellent yields of products, short reaction times, cost efficiency, atom economy, and a simple workup procedure with no need for extra purification techniques. Moreover, the catalyst can be easily recovered and reused for up to three cycles without losing any significant activity.

Automated summary

A series of pyrano[3,2-c]quinolone derivatives were successfully synthesized using taurine as a green bio-organic catalyst and water as the solvent. The protocol offers excellent yields, short reaction times, cost efficiency, atom economy, and easy catalyst recovery and reuse.