Background: Nanoscale metal oxide catalysts have been extensively employed in organic reactions
because they have been found to influence the chemical and physical properties of bulk material. The
chromene (benzopyran) nucleus constitutes the core structure in a major class of many biologically active
compounds, and interest in their chemistry consequently continues because of their numerous biological activities.
The xanthene (dibenzopyran) derivatives are classified as highly significant compounds which display
a number of various bioactive properties. Pyrimidinones have also gained interest due to their remarkable
biological utilization, such as antiviral, antibacterial, antihypertensive, antitumor, and calcium blockers
Objective: The aim of this work presented herein was to prepare activated carbon/MoO3 nanocomposite and
explore its role as a green and recyclable catalyst for the synthesis of chromeno[d]pyrimidinediones and xanthenones
under ethanol-drop grinding at room temperature.
Methods: The activated carbon/MoO3 nanocomposite was prepared successfully via a simple route in which
the carbonization of gums as new natural precursors was used for the synthesis of activated carbon. This
nanocomposite was then effectively used in a reaction of 3,4-methylenedioxyphenol, aromatic aldehydes,
and active methylene compounds, including 1,3-dimethylbarbituric acid and dimedone, to synthesize a series
of chromeno[d]pyrimidinediones and xanthenones in high yields. The synthesized catalyst was characterized
by Fourier transform infrared spectroscopy (FT-IR), Powder x-ray diffractometry (XRD), Scanning electron
microscope (SEM), Raman spectroscopy, and also by TGA analysis. Confirmation of the structures of
compounds 5(a-g) and 6(a-g) were also established with IR, 1H NMR, and 13C NMR spectroscopic data and
also by elemental analyses.
Results: A number of 6,8-dimethyl-10-phenyl-6,10-dihydro-7H-[1,3]dioxolo[4´,5´:6,7]chromeno[2,3-
d]pyrimidine-7,9(8H)-diones and 7,7-dimethyl-10-(4-methylphenyl)-6,7,8,10-tetrahydro-9H-[1,3]dioxolo[
4,5-b]xanthen-9-ones were effectively synthesized using activated carbon/MoO3 nanocomposite (0.05
gr) as a catalyst under ethanol-drop grinding at room temperature. The desired products were obtained in
high yields (93-97%) within short reaction times (15-20 min).
Conclusion: This paper investigates the catalytic potential of the synthesized activated carbon/MoO3 nanocomposite
for the preparation of chromeno[d]pyrimidinediones and xanthenones under the ethanol-drop
grinding procedure. The mildness of the reaction conditions, high yields of products, short reaction times, experimental
simplicity, and avoiding the use of harmful solvents or reagents makes this procedure preferable
for the synthesis of these compounds.