Copper Immobilized on Modified LDHs as a Novel Efficient Catalytic System for Three-Component Synthesis of Pyrano[2,3-]pyrimidine and pyrazolo[4',3':5,6]pyrano[2,3-]pyrimidine Derivatives.

A novel catalyst based on layered double hydroxides coated with copper nitrate [LDH@(3-chloropropyl)trimethoxysilane@N1,N4-(4,6-diamino-1,3,5-triazin-2-yl)benzene-1,4-disulfonamide@Cu] was successfully synthesized. The structure of the new synthesized catalyst was investigated and confirmed using different analytical techniques, such as Fourier-transform infrared spectroscopy (FTIR), energy-scattered X-ray spectroscopy (EDX) mapping, X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and heat gravity/heat derivatization (TGA/DSC). The skilled catalyst proved its efficiency for one-pot three-component synthesis of pyrano[2,3-]pyrimidine and new dihydropyrazolo[4',3':5,6]pyrano[2,3-]pyrimidine-dione derivatives. Using this efficient catalyst, products were synthesized with a high yield, in a short time, and under soft and solvent-free conditions. The catalyst can be recovered and reused four times without a significant loss of efficiency.