Zr(HSO_4)_4-catalyzed one-pot three-component synthesis of 7-alkyl-6H,7H-naphtho[1′,2′:5,6]pyrano[3,2-c]chromen-6-ones

摘要

A new, one-pot, simple thermally efficient and solvent-free method for the preparation of 7-alkyl-6H,7H-naphtho[1′,2′:5,6]pyrano[3,2-c]chromen- 6-ones by condensation of β-naphthol, aromatic aldehydes, and 4-hydroxycoumarin using Zr(HSO_4)_4 as a safe and efficient catalyst is described. This method has the advantages of high yields, a cleaner reaction, simple methodology, short reaction times, easy workup, and greener conditions.