Aim and Objective: The xanthene (dibenzopyran) framework constitutes the core
structure of many biologically active compounds, that they have been of interest because of their
pharmacological activities like antiviral, antibacterial, anti-inflammatory, and CCR1 antagonist. As
heterogeneous catalysts offer several advantages over homogeneous catalysts, the performance of
reactions on the surface of nanosized heterogeneous salts has received a great deal of interest in
recent years. In the area of nanosized heterogeneous catalysts there is a noticeable range of reactions
that are catalyzed efficiently by TiO2 NPs. Moreover, carbon nanotubes (CNTs) as a support can be
used to obtain nanoparticles with modified morphology, structural, chemical, electrical, and optical
properties. The catalytic activity of titanium dioxide supported on carbon nanotubes has been greatly
Materials and Methods: The present methodology focus on the synthesis of 7,7-dimethyl-10-aryl-
6,7,8,10-tetrahydro-9H-[1,3]dioxolo[4,5-b]xanthen-9-ones, through a condensation reaction of
dimedone, aromatic aldehydes and 3,4-methylenedioxyphenol, using a catalytic amount of TiO2-
CNTs nanocomposite (15 mol%) at 80 ˚C in aqueous media, within 60-90 min. The TiO2-CNTs
nanocomposite was also prepared by a known simple sonochemical method.
Results: A series of 7,7-dimethyl-10-aryl-6,7,8,10-tetrahydro-9H-[1,3]dioxolo[4,5-b]xanthen-9-ones
were successfully synthesized in high yields (92-98%). All synthesized compounds were well
characterized by their satisfactory elemental analyses, IR, 1H and 13C NMR spectroscopy. The
synthesized catalyst was fully characterized by SEM, TEM, XRD, and EDX techniques.
Conclusion: In summary, this investigation constitutes a novel and efficient route for the synthesis
of 7,7-dimethyl-10-aryl-6,7,8,10-tetrahydro-9H-[1,3]dioxolo[4,5-b]xanthen-9-ones in high yields, by
a three-component reaction of dimedone, aromatic aldehydes and 3,4-methylenedioxyphenol in
water and in the presence of the TiO2-CNTs nanocomposite as a green, effective and recyclable
catalyst. This novel method has the advantages of high yields, mild reaction conditions, short
reaction time, easy work-up, inexpensive reagents and environmentally friendly procedure.