Anti-cancer,anti-oxidant and molecular docking studies of thiosemicarbazone indole-based derivatives

Based on the structural elements of bioactive 3-substituted indoles, a new series of indole–thiosemicarbazone hybrid derivatives were designed, synthesized, and well-characterized using different spectral techniques. The intended scaffolds were screened for their in vitro anti-proliferative activities against breast cancer (MCF-7), lung cancer (A-549), and liver cancer (Hep-G2) cell lines, as well as their anti-oxidant properties. Cytotoxicity studies revealed that compound 6n was the most potent, at least threefold more potent than the commercially available reference drug etoposide, against A-549. In addition, morphological analysis by the acridine orange/ethidium bromide double staining test and flow cytometry analysis confirmed induction of apoptosis in the A-549 cells by compound 6n. In order to validate the experimental results, molecular studies were performed to achieve the possible binding interactions of the most potent compound (6n) and colchicine with tubulin as well as ANP with ATPase domain of topoisomerase IIα active sites. Moreover, the radical scavenging potential of the final derivatives was found to be excellent with the range of 0.015–0.630 µM, comparable to the standard ascorbic acid (0.655 µM).

     

Solvent‐free synthesis of propargylamines catalyzed by an efficient recyclable ZnO‐supported CuO/Al2O3 nanocatalyst

An efficient nanocatalyst of ZnO‐supported CuO/Al₂O₃ (CuO/ZnO/Al₂O₃ nanocatalyst) was prepared by the co‐precipitation method and characterized by scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, X‐ray powder diffraction and Brunauer–Emmett–Teller surface area analysis. CuO/ZnO/Al₂O₃ nanocatalyst proved to be a very efficient catalyst on the synthesis of propargylamines under solvent‐free conditions in high yields. Moreover, the catalyst can be recyclable without reducing catalytic activity up to five times.     

Synthesis of gem-Dihydroperoxides from Ketones and Aldehydes Using Silica Sulfuric Acid as Heterogeneous Reusable Catalyst

Silica sulfuric acid (SSA) was found to efficiently catalyze the conversion of aldehydes and ketones directly into the corresponding gem-dihydroperoxides (DHPs) on treatment with aqueous 30% H₂O₂ at room temperature. Mild reaction conditions, good to excellent yields, short reaction times, low environmental impact, and recyclability of the catalyst are the main advantages of this synthetic method.     

One‐pot multicomponent synthesis of novel 2‐(piperazin‐1‐yl) quinoxaline and benzimidazole derivatives,using a novel sulfamic acid functionalized Fe3O4 MNPs as highly effective nanocatalyst

The immobilization of sulfonic acid on the surface of Fe₃O₄ magnetic nanoparticles (MNPs) as a novel acid nanocatalyst has been successfully reported. The morphological features, thermal stability, magnetic properties, and other physicochemical properties of the prepared superparamagnetic core–shell (Fe₃O₄@PFBA–Metformin@SO₃H) were thoroughly characterized using Fourier transform infrared (FTIR), X‐ray diffraction (XRD), energy‐dispersive X‐ray spectroscopy (EDS), field‐emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis–differential thermal analysis (TGA‐DTA), atomic force microscopy (AFM), dynamic light scattering (DLS), Brunauer–Emmett–Teller (BET), and vibrating sample magnetometer (VSM) techniques. It was applied as an efficient and reusable catalyst for the synthesis of 2‐(piperazin‐1‐yl) quinoxaline and benzimidazole derivatives via a one‐pot multiple‐component cascade reaction under green conditions. The results displayed the excellent catalytic activity of Fe₃O₄@PFBA–metformin@SO₃H as an organic–inorganic hybrid nanocatalyst in condensation and multicomponent Mannich‐type reactions. The easy separation, simple workup, excellent stability, and reusability of the nanocatalyst and quantitative yields of products and short reaction time are some outstanding advantages of this protocol.     

Optimal standby activation in m-out-of-n systems: A preventive approach

This article investigates an optimal preventive standby activation policy for an $m$-out-of-$n$ redundant system. We assume that for such a system, which starts operating at time $t=0$, a standby component will be activated at either the failure time of the system or at a predetermined time $\tau$, whichever occurs first. We first obtain the system reliability function under this switching policy as a function of $\tau$. Then, we investigate the optimal switching time $\tau$ so that the mean time to failure of the system is maximized. The results indicate that the existence of an optimal value of $\tau$ depends on the lifetime of the standby redundancy and its virtual age in the standby state. Some illustrative examples are presented to examine the theoretical outcomes.