Efficient Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones Catalyzed by a Cd-Based Covalent Organic Framework Under Solvent-Free Conditions

A porous covalent organic framework (COF) was synthesized through the condensation reaction of melamine and phthalic acid and Cadmium acetate was then incorporated into the COF through a straightforward post-treatment. Cd-COF as a catalyst was assessed in the one-pot three-component Biginelli-type reaction, involving aldehydes, beta-diketones, and urea. It demonstrated exceptional activity and selectivity, promoting the environmentally friendly synthesis of various 3,4-dihydropyrimidin-2(1H)-ones without organic solvents. Characterization using FT-IR, SEM, EDS, PXRD, TGA, and(1)H-NMR analysis provided valuable insights into the catalyst's structure and properties. This method is categorized by its effective catalyst, straightforward workup process, uncomplicated separation that does not require chromatography, and the ability to reuse Cd-COF up to four times. These key aspects underscore the significance of this approach, which is expected to be extensively applied in both academic and industrial research