Saman Dahi-Azar, Shahrzad Abdolmohammadi* and Javad Mokhtari Pages 1 - 9 ( 9 )
Aim and Objective: In the last decades, it has been extensively verified that nanostructured transition metal oxides emerge as inexpensive, available and extremely efficient heterogeneous catalysts in chemical transformations. The high electrical conductivity, high carrier concentration, and improved reactivity in cadmium oxide nanoparticles (CdO NPs) make it as a potential candidate for applications in the fields of nanocatalysis. Benzopyran and pyridopyrimidine derivatives compose major classes of heterocyclic compounds, which have a wide spectrum of biologically activities.
Materials and Methods: In the present work we report a facile and highly effective synthesis of 8-aryl-8H-[1,3]dioxolo[4,5- g]benzopyran-6-carboxylic acids and 1,3-dimethyl-2,4-dioxo-5-phenyl-1,2,3,4,5,8-hexahydropyrido[2,3-d]pyrimidine-7- carboxylic acids via CdO NPs catalyzed cyclocondensation reaction of 4-substituted phenylmethylidenepyruvic acids with 3,4- methylenedioxyphenol or 1,3-dimethylbarbituric acid which was accomplished under ethanol-drop grinding at room temperature. The described catalyst was prepared successfully by a simple precipitation method and characterized by the Fourier transformed infrared absorption (FT-IR) spectroscopy, X-Ray diffraction (XRD) analytical technique, and scanning electron microscopy (SEM).
Results: A number of [1,3]dioxolo[g]benzopyran-6-carboxylic acids and pyrido[d]pyrimidine-7-carboxylic acids were effectively synthesized in high yields (96-98%) within short reaction times (10-15 min). All synthesized compounds were well characterized by IR, 1H and 13C NMR spectroscopy, and also by elemental analyses.
Conclusion: In summary, we have developed a very simple and impressive procedure for the synthesis of 8-aryl-8H- [1,3]dioxolo[4,5-g]benzopyran-6-carboxylic acids and 1,3-dimethyl-2,4-dioxo-5-phenyl-1,2,3,4,5,8-hexahydropyrido[2,3- d]pyrimidine-7-carboxylic acids as biologically interesting structures in the presence of CdO NPs as an efficient recyclable heterogeneous catalyst. The remarkable advantages for the offered protocol compared with traditional methods are short reaction time, good yields of the products, and the ease of operation with simple work-up procedure.
Benzopyrans, cadmium oxide nanoparticles (CdO NPs), ethanol-drop grinding, pyridopyrimidines, reusability of catalyst, 4-substituted phenylmethylidenepyruvic acids.
Department of Chemistry, Science and Research Branch, Islamic Azad University, P.O. Box 14515-775, Tehran, Department of Chemistry, East Tehran Branch, Islamic Azad University, P.O. Box 18735-138, Tehran, Department of Chemistry, Science and Research Branch, Islamic Azad University, P.O. Box 14515-775, Tehran