Ultrasound-mediated, uranyl nitrate hexahydrate-catalyzed synthesis of 1,4-dihydropyridines under mild conditions

SBA-15 obtained from rice husk ashes wet-impregnated with metals (Al, Co, Ni) as efficient catalysts for 1,4-dihydropyridine three-component reaction

A fully characterized mesoporous silica prepared from industrial waste was impregnated with metals and applied as a green heterogeneous catalyst.

Antimicrobial, anticoagulant, and cytotoxic evaluation of multidrug resistance of new 1,4-dihydropyridine derivatives

A new series of 1,4-dihydropyridine derivatives (2a–h, 3a–e, and 4a–e) were systematically designed and synthesized via ultrasound irradiation methods with easy work-up and good yields. Compounds structures were confirmed by IR, ¹H NMR, ¹³C NMR, and mass spectra. The synthesized compounds were screened for both antimicrobial and anticoagulant activities. Compound 2e (MIC: 0.25 μg/mL) was highly active against Escherichia coli and compound 2c (MIC: 0.5 μg/mL) was also highly active against Pseudomonas aeruginosa compared with ciprofloxacin. (MIC: 1 μg/mL) The antifungal activity of 2c (MIC: 0.5 μg/mL) against Candida albicans was high relative to that of clotrimazole (MIC: 1 μg/mL). Anticoagulant activity was determined by activated partial thromboplastin time (APTT) and prothrombin time (PT) coagulation assays. Compound 4-(4-hydroxyphenyl)-2,6-dimethyl-N³,N⁵-bis(5-phenyl-1,3,4-thiadiazol-2-yl)-1,4-dihydropyridine-3,5-dicarboxamide 3d (>1000 s in APTT assays) was highly active in anticoagulant screening compared with the reference of heparin.

Cytotoxicity was evaluated using HepG2 (liver), HeLa (cervical), and MCF-7 (breast) cancer cell lines, with high toxicities observed for 2c (GI₅₀ = 0.02 μm) against HeLa cell line and 2e (GI₅₀ = 0.03 μm) equipotant against MCF-7 cell line. Therefore, the compounds 2e, 2c and 3d can serve as lead molecules for the development of new classes of antimicrobial and anticoagulant agent.