An economical and efficient green chemical method is developed for the synthesis of multi-functionalized benzene derivatives through a natural biopolymer Cellulose Sulfuric Acid (CSA) as a heterogeneous catalytic sequence of Knoevenagal/Michael/Cyclization under solvent-free conditions at 70 o C. The metal-free catalytic system under solvent-free condition processes the reactions with a good efficiency. This protocol should be amenable advantages such as simple workup and recoverability of the biopolymer catalyst and reusing several times without significant decrease in catalytic activity.
Sulfated tin oxide (STO) was established as an admirable heterogeneous catalyst for the single‐step synthesis of dihydropyridine derivatives via Hantzsch reaction. The synthetic method was mainly used in the presence of STO as a heterogeneous solid catalyst. STO‐catalyzed Hantzsch reaction afforded good yields (90–94%) in acetonitrile at 80°C. The synthesized titled compounds were characterized and confirmed by High Resolution Mass Spectroscopy (HRMS), Fourier Tranform‐Infrared (FTIR), 1H and 13C‐NMR, and spectral data.
An efficient and promising synthetic approach to assemble skeletons of multifunctionalized pyridine derivatives in presence of recyclable heterogeneous sulfated tin oxide (STO) catalyst has been evolved. The STO catalyst was used as a promoter for the cyclocondensation process in ethanol at 70°C. Overall performance of this catalyst was attributed to the cooperative contribution of its Lewis and Brønsted-Lowry acidic sites. Nanosized STO catalyst was synthesized by using sol-gel process and characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), 1 H-NMR, and scanning electron microscopy (SEM). This catalyst tolerates most of the substrates, and protocol shows precious capabilities consist of high yields, operational simplicity, less reaction time, and eco-friendly conditions. The newly synthesized heterogeneous catalyst was easily separated and reused. All the reactions are carried out for subsequent cycles without significant loss of catalytic activity and with good proficiency.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.