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The activity of a V2O5/TiO2–Al2O3 catalyst for oxidative dehydrogenation of ethylbenzene to styrene with various V2O5 loadings in the presence of CO2 and N2 was studied. Among the different loadings of V2O5, the 5 wt% V2O5/TiO2–Al2O3 catalyst exhibited better activity. The incorporation of TiO2 into the Al2O3 support greatly influenced the activity of the catalyst. The maximum conversion of ethylbenzene and styrene selectivity were observed to be 65% and 96%, respectively, at 550 °C and notable stability was observed up to 60 hours with CO2. The conversion directly depends on the availability of active V5+ sites. The facile redox cycle between fully oxidized and reduced V species was effective for the reaction. The catalysts were characterized by X-ray diffraction, Raman spectroscopy, BET surface area and pore size distribution, scanning electron microscopy, and H2–temperature programmed reduction. The results indicate that the surface area, interaction with the support, morphology of the catalyst and surface active sites had a significant influence on the activity. [ABSTRACT FROM AUTHOR]

N-acyliminium ions are that can act as electron-deficient electrophiles toward weak or soft nucleophiles, thereby providing useful methods for both intermolecular- and carbon-carbon and carbon-heteroatom bond formation. to N-acyliminium ions constitute an important method for providing α-functionalized amino compounds and many other nitrogen-containing heterocycles. The development of efficient catalytic is a key objective in modern organic chemistry and is very important for the synthesis of natural products, pharmaceuticals, and agrochemicals. Various methods are available for this purpose and mostly rely on the use of chiral catalysts for . This review deals with one aspect of such , which has emerged only in the past few years, and its applications in of N-acyliminium ions to provide various nitrogen-containing heterocycles. [ABSTRACT FROM AUTHOR]

Abstract: A novel series of 3-chloro-4-[4-(2-oxo-2H-chromen-4-ylmethoxy)-phenyl]-1-phenyl-azetidin-2-one derivatives (5a–j) have been synthesized from 4-aryloxymethylcoumarins (1a–e) and 4-aryliminomethyl-phenols (3a–b). The title compounds were screened for their in vitro anti-bacterial and anti-fungal activities. Results revealed that, compounds (5c), (5f), (5h) and (5j) showed excellent anti-microbial activity against a panel of microorganisms. Brine shrimp bioassay was also carried out to study their in vitro cytotoxic properties among which (5h) and (5j) displayed potent cytotoxic activity against Artemia salina. The DNA cleavage activity of some compounds was studied by agarose gel electrophoresis method. All synthesized compounds were characterized using IR, 1H NMR, 13C NMR, MS and elemental analysis. [Copyright &y& Elsevier]

ABSTRACT A series of sterically varied silver‐based N‐heterocyclic carbene (NHC) complexes (14–17) were synthesized by embroidering biomedically active coumarin and 1,2,4‐triazole core as NHC precursors (10–13). The structure of all the synthesized salts (10–13) and complexes (14–17) were elucidated by FT‐IR and NMR (proton and carbon) spectroscopic techniques. Complex 15 was characterized by single‐crystal x‐ray diffraction. The data obtained from this characterization of the small molecule 15 confirmed the three‐dimensional arrangement of the complex. This also indicated agostic‐type interactions between the Ag atom and the CH modules of one of the NHC ligands. Further, the synthesized complexes (14–17) were studied for the antihaemolytic, anticoagulant and anticancer activities. The complexes 15 and 17 exhibited anticoagulant properties comparable to that of the standard anticoagulant EDTA. Notably, all the complexes evidenced anticancer activity on leukaemic cell lines (K562) with the IC50 values below 100 μM, the concentration at which antihaemolytic property was evidenced. Complex 15 exhibited the lowest IC50 value of 18.44 ± 0.76 μM, which could be attributed by the appropriate steric bulk around the metal atom. The cumulative data of the three analyses validate potential of the complexes 15 and 17 to exhibit antihaemolytic, anticancer and anticoagulant properties. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a severe age-dependent neurodegenerative disorder affecting millions of people, with no cure so far. The current treatments only achieve some temporary amelioration of the cognition symptoms. The main characteristics of the patient brains include the accumulation of amyloid plaques and neurofibrillary tangles (outside and inside the neurons) but also cholinergic deficit, increased oxidative stress and dyshomeostasis of transition metal ions. Considering the multi-factorial nature of AD, we report herein the development of a novel series of potential multi-target directed drugs which, besides the capacity to recover the cholinergic neurons, can also target other AD hallmarks. The novel series of tacrine-hydroxyphenylbenzimidazole (TAC-BIM) hybrid molecules has been designed, synthesized and studied for their multiple biological activities. These agents showed improved AChE inhibitory activity (IC 50 in nanomolar range), as compared with the single drug tacrine (TAC), and also a high inhibition of self-induced- and Cu-induced-Aβ aggregation (up to 75%). They also present moderate radical scavenging activity and metal chelating ability. In addition, neuroprotective studies revealed that all these tested compounds are able to inhibit the neurotoxicity induced by Aβ and Fe/AscH(-) in neuronal cells. Hence, for this set of hybrids, structure-activity relationships are discussed and finally it is highlighted their real promising interest as potential anti-AD drugs. [ABSTRACT FROM AUTHOR]

The activity of a V2O5/TiO2–Al2O3 catalyst for oxidative dehydrogenation of ethylbenzene to styrene with various V2O5 loadings in the presence of CO2 and N2 was studied. Among the different loadings of V2O5, the 5 wt% V2O5/TiO2–Al2O3 catalyst exhibited better activity. The incorporation of TiO2 into the Al2O3 support greatly influenced the activity of the catalyst. The maximum conversion of ethylbenzene and styrene selectivity were observed to be 65% and 96%, respectively, at 550 °C and notable stability was observed up to 60 hours with CO2. The conversion directly depends on the availability of active V5+ sites. The facile redox cycle between fully oxidized and reduced V species was effective for the reaction. The catalysts were characterized by X-ray diffraction, Raman spectroscopy, BET surface area and pore size distribution, scanning electron microscopy, and H2–temperature programmed reduction. The results indicate that the surface area, interaction with the support, morphology of the catalyst and surface active sites had a significant influence on the activity. [ABSTRACT FROM AUTHOR]

Heterocyclic compounds are of great interest in our daily lives. They are widely distributed in nature and are synthesized in laboratories. Heterocycles play an important role in the metabolism of all living cells, including vitamins and coenzyme precursors like thiamine and riboflavin. Furthermore, heterocyclic systems are essential building blocks for creating innovative materials with intriguing electrical, mechanical, and biological properties. Also, more than 85% of all biologically active chemical entities comprise a heterocycle. As a result, heterocycle synthesis piqued researchers' curiosity, and in recent decades, chemists have concentrated more on nitrogen-containing cyclic nuclei in structures. Quinoline and its derivatives exhibit several biological functions, including antimicrobial, anticancer, antimalarial, anti-inflammatory, antihypertensive, and antiasthmatic effects. In addition, over a hundred quinoline-based drugs are available to treat a variety of disorders. Because of its biological importance, researchers developed one-pot synthetic methods employing effective acid/base catalysts (Lewis acids, Brønsted acids, and ionic liquids), reagents, and transition-metal-based catalysts. These methods have some downsides, including longer reaction times, harsher reaction conditions, creation of byproducts, costly catalysts, use of hazardous solvents, an unacceptable economic yield, and catalyst recovery. Researchers' focus has switched to creating environmentally friendly and effective methods for the synthesis of quinoline derivatives as a result of these methodologic shortcomings. Because of its special qualities, the use of nanocatalysts or nanocomposites offers an option for the effective synthesis of quinolines. This review focuses on the published research articles on nanocatalysts to synthesize substituted quinoline derivatives. This review covers all contributions until May 2024, focusing on quinoline ring building and mechanistic issues. With the aid of this review, we anticipate that synthetic chemists will be able to develop more effective methods of synthesizing quinolines., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Use of biomaterial scaffolds as drug carriers for infected wounds treatment is of wide scope. A series of curcumin/TiO 2 complex loaded chitosan scaffolds are fabricated for the same. Synthesized wound dressing material is screened for their morphology, water absorption capacity; in vitro drug release patterns, in vitro antibacterial studies against gram +ve and a gram -ve bacteria, cell viability for 3T3-L1 cell lines as well as in vivo MRSA infected wound healing capability. Formation of curcumin/TiO 2 complex was confirmed by X-ray diffraction studies, the anchoring pattern of them on the chitosan scaffold was analyzed by FESEM and EDS mapping. All membranes showed a better performance towards in vitro antibacterial and in vivo wound healing properties than the control ones in 14 days. The bacterial count on wound for a regular time period was measured and the scaffold with higher amount of curcumin in its complex is found to give the better performance, along with skin regeneration due to synergistic effect of curcumin and TiO 2 ., Competing Interests: Declaration of competing interest Authors declare no conflict of interest., (Copyright © 2019. Published by Elsevier B.V.)

N-acyliminium ions are reactive intermediates that can act as electron-deficient electrophiles toward weak or soft nucleophiles, thereby providing useful methods for both intermolecular- and intramolecular carbon-carbon and carbon-heteroatom bond formation. Nucleophilic additions to N-acyliminium ions constitute an important method for providing α-functionalized amino compounds and many other biologically active nitrogen-containing heterocycles. The development of efficient catalytic asymmetric reactions is a key objective in modern organic chemistry and is very important for the synthesis of natural products, pharmaceuticals, and agrochemicals. Various methods are available for this purpose and mostly rely on the use of chiral catalysts for enantioselective synthesis. This review deals with one aspect of such catalysis, which has emerged only in the past few years, and its applications in enantioselective reactions of N-acyliminium ions to provide various nitrogen-containing heterocycles., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)