Magnetically reusable nanocatalysts in biginelli synthesis of dihydropyrimidinones (DHPMs)

Promising photocatalytic and antimicrobial activity of novel capsaicin coated cobalt ferrite nanocatalyst

In this study, CoFe₂O₄ nanoparticles were prepared by the co-precipitation method then surface modified with Capsaicin (Capsicum annuum ssp.). The virgin CoFe₂O₄ NPs and Capsaicin-coated CoFe₂O₄ NPs (CPCF NPs) were characterized by XRD, FTIR, SEM, and TEM. The antimicrobial potential and photocatalytic degradation efficiencies of the prepared samples via Fuchsine basic (FB) were investigated. The results revealed that CoFe₂O₄ NPs have spherical shapes and their diameter varied from 18.0 to 30.0 nm with an average particle size of 25.0 nm. Antimicrobial activity was tested on Gram-positive (S. aureusATCC 52923) and Gram-negative (E. coli ATCC 52922) by disk diffusion and broth dilution methods to determine the zone of inhibition (ZOI) and minimum inhibitory concentration (MIC), respectively. UV-assisted photocatalytic degradation of FB was examined. Various parameters affecting the photocatalytic efficiency such as pH, initial concentration of FB, and dose of nanocatalyst were studied. The in-vitro ZOI and MIC results verified that CPCF NPs were more active upon Gram-Positive S. aureus ATCC 52923 (23.0 mm ZOI and 0.625 μg/ml MIC) than Gram-Negative E. coli ATCC 52922 (17.0 mm ZOI and 1.250 μg/ml MIC). Results obtained from the photocatalytic activity indicated that the maximum FB removal achieving 94.6% in equilibrium was observed using 20.0 mg of CPCF NPS at pH 9.0. The synthesized CPCF NPs were effective in the removal of FB and also as potent antimicrobial agent against both Gram-positive and Gram-negative bacteria with potential medical and environmental applications.

Sulfonated carbons from agro-industrial residues: simple and efficient catalysts for the Biginelli reaction

An eco-friendly catalyst prepared from rice husk was used to synthesize dihydropyrimidinones (DHPMs) and achieved a yield of 92%.

Synthesis, crystal structure and antibacterial studies of dihydropyrimidines and their regioselectively oxidized products

The syntheses and investigations of new biologically active derivatives of dihydropyrimidines by Biginelli reaction in the presence of copper triflate are reported. Due to the fact that salicylaldehyde and its derivatives under Biginelli reaction conditions can lead to the formation of 2 types of dihydropyrimidines, the influence of copper triflate on product formation was also investigated. In addition to this, regioselective oxidation of dihydropyrimidines was performed in the presence of cerium ammonium nitrate and novel oxidized dihydropyrimidines were obtained. Single crystals of some of them were obtained and as a result, the structures of them were investigated by X-ray diffraction method, which allows determining the presence of hydrogen bonds in their structures. In addition to this, the presence of hydrogen bonds in their structures affects the formation of the corresponding tautomer during oxidizing of dihydropyrimidines. Since dihydropyrimidines are claimed to be biologically active compounds, activities of the synthesized compounds were studied against Acinetobacter baumanii, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus bacteria.

Known methods of synthesis of dihydropyrimidines and their oxidized products were modified, the impact of hydrogen bonds on stabilization of preferred tautomer and biological activities were studied.

Pharmacophore modeling, design, and synthesis of potent antihypertensives, oxazolo/thiazolo-[3,2-a]-pyrimidin-3(2H)-one, and 1,5-dihydroimidazo-[1,2-a]-pyrimidin-3(2H)-one derivatives: A pilot trial

An improved pharmacophore model, molecular properties, geometric analyses, and SAR led to synthesize oxazolo/thiazolo-[3,2-a]-pyrimidin-3(2H)-one, and 1,5-dihydroimidazo-[1,2-a]-pyrimidin-3(2H)-one derivatives exhibiting potent anti-hypertensive activity. The 6-ethoxycarbonyl-2,7-dimethyl-5-phenyl-1,5-dihydroimidazo[3,2-a]pyrimidin-3(2H)-one (4g), and 6-ethoxycarbonyl-2,7-dimethyl-5-(3-methyl-phenyl)-1,5-dihydroimidazo[3,2-a]pyrimidin-3(2H)-one (4h) showed significant reduction in mean arterial blood pressure (MABP, mm/Hg) of 79.78%, and 92.95% in 6 and 12 h durations, respectively, at 1.5 mg/kg body-weight dose, while at 3.0 mg/kg body-weight dose, the MABP reduction was achieved at 95.46%, and 92.02%, respectively, in 6 and 12 h durations, as compared to the standard drug, nifedipine.