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Two new monobasic tridentate O⁀N⁀N donor ligands, HL1 (I) and HL2 (II) have been obtained in two steps by reacting phenylhydrazine and salicylaldehyde or 3,5-di-tert-butylsalicylaldehyde and then reacting the resulting compounds with 2-chloromethylbenzimidazole in the presence of triethylamine. The reaction of [VIVO(acac)2] with these ligands in a 1:1 molar ratio in dry methanol led to the formation of homogeneous oxidovanadium(IV) complexes [VIVO(acac)L1] (1) and [VIVO(acac)L2] (2). Immobilization of these complexes on chloromethylated polystyrene (PS-Cl) cross-linked with divinyl benzene resulted in corresponding polymer-supported heterogeneous complexes PS-[VIVO(acac)L1] (3) and PS-[VIVO(acac)L2] (4). Ligands (I and II), homogeneous complexes (1 and 2) and heterogeneous complexes (3 and 4) have been characterized using elemental analysis and various spectroscopic techniques. A single crystal X-ray diffraction study of I and 1 further confirms their structures. The oxidation state IV of vanadium in these complexes was assured by recording their EPR spectra while heterogeneous complexes were further characterized using field emission-scanning electron microscopy (FE-SEM) combined with energy dispersive X-ray analysis (EDS) and atomic force microscopy (AFM). All vanadium complexes have been explored for their catalytic potential to one-pot-three-component reactions (reagents: benzil, ammonium acetate and various aromatic aldehydes) for the efficient synthesis of 2,4,5-triphenyl-1H-imidazole derivatives (nine examples). Various reaction conditions have been optimized to obtain a maximum yield (up to 96%) of catalytic products. It has been found that heterogeneous complexes show excellent catalytic activity and are recyclable up to five catalytic cycles. [ABSTRACT FROM AUTHOR]

In the presented synthetic work, a series of novel substituted 1, 4-Dihydropyridine derivatives (DHPs) have been prepared by the reaction of substituted aromatic aldehydes, ethyl acetoacetate, and ammonium acetate in the presence of a heterogeneous catalyst silica sulfuric acid at ambient temperature via expeditious, mild, inexpensive and one pot Hantszch multicomponent synthetic methodology. Various benefits of this approach are simple work-up; short reaction times at ambient reaction temperature, excellent yields, green solvent system, no by-products and purification of products without chromatographic separation. The catalyst was easily recovered by simple filtration and reused up to five times without washing with any solvent and without major loss in its activity. All the synthesized compounds were characterized by IR, 1H NMR, 13C NMR and LC-Mass spectroscopic techniques. Molecular modelling of the synthesized novel compounds with respect to Lipinski rule of five, drug likeness, toxicity profiles, drug score and other physico-chemical properties are described and compared with market available generic drugs. Theoretical screenings data suggested that the reported compounds possessed a broad range of lipophilic character, no toxicity risks and similar bioactivity scores as relative with standard drugs used for comparison.

A novel, eco‐friendly super paramagnetic organo‐nano catalyst was fabricated by encapsulating ferrite@silica (Fe3O4@SiO2) nanoparticles with l‐Glutamine. The prepared catalyst was characterized by various analytical techniques viz., fourier transform infrared spectroscopy (FT‐IR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Energy Dispersive X‐ray analysis (EDX), powder X‐ray diffraction technique (XRD), vibrating sample magnetometer spectroscopy (VSM), Inductively coupled plasma optical emission spectroscopy (ICP‐OES) and its catalytic activity was investigated for the synthesis of spirooxindole derivatives. Utilizing the ferromagnetic nature of Fe3O4 nanoparticles, the prepared catalyst could be easily retrieved from the reaction mixture after completion of the reaction by using an external magnet. The catalyst was reused up to six runs with remarkable catalytic activity. The main advantages of this synthetic approach lie in its operational simplicity, cost effectiveness, higher yields, easy catalyst recyclability and reusability, eco‐friendly procedures and shorter reaction times. Also, the antimicrobial assay of the synthesized spirooxoindoles was evaluated against three bacterial isolates and one fungal isolate, and the results showed profound antimicrobial activities. [ABSTRACT FROM AUTHOR]