TiO2 NP & catalyst for the synthesis of benzopyrano benzopyranone and xanthenol in water

(Bentham Science Publishers) In this research, TiO2-CNTs were used as an efficient recyclable catalyst for the synthesis of [1]benzopyrano[b][1]benzopyran-6-ones and xanthenols by the pseudo three-component reaction of salicylaldehydes with active methylene compounds including 4-hydroxycoumarin (4- hydroxy-2H-1-benzopyran-2-one) or 3,4-methylenedioxyphenol. The introduced method is mild, environmentally benign and effective to give the products in high yields and in short reaction times.