RESUMEN

This work is focused on designing an innovative, efficient, and reusable heterogeneous ZnO/CuI/PPy nanocomposite via the self-assembly approach where pyrrole is oxidized into polypyrrole (PPy) and pyrrole also behaves as a reductant in the presence of KI. This so-obtained material was characterized by XRD, FTIR, FESEM, EDX, TEM, XPS, and ICP. TEM clearly shows a spherical morphology with the particle size ranging between 18 and 42 nm. The fabricated nanomaterial was tested for one-pot catalytic synthesis of biologically active 2,4,5-trisubstituted imidazoles under solvent-free conditions. The present work includes the benefits of an easy work-up procedure, higher product yield, shorter reaction duration, and no additional additive requirement under green and sustainable conditions. Moreover, the catalyst exhibited reusability for six runs with no considerable reduction in the respective yields and reactivity (confirmed by XRD, SEM, and TEM of the recycled catalyst). The ICP study shows very low leaching of copper (2.08 ppm) and zinc (0.12 ppm) metals. The approach also presented better values of green metrics like the E-factor, process mass intensity, carbon efficiency and reaction mass efficiency.

RESUMEN

2,3-Dihydroquinazolinone derivatives are known for antiviral, antimicrobial, analgesic, anti-inflammatory, and anticancer activities. However, recent approaches used for their synthesis suffer from various drawbacks. Therefore, we have fabricated a highly efficient magnetic EDTA-coated catalyst, Fe3O4@EDTA/CuI via a simple approach. The ethylenediamine tetraacetic acid (EDTA) plays a crucial role by strongly trapping the catalytic sites of CuI nanoparticles on the surface of the Fe3O4 core. The designed nanocatalyst demonstrates its potential for the catalytic synthesis of 2,3-dihydroquinazolinones using 2-aminobenzamide with aldehydes as the reaction partners. The nanocatalyst was thoroughly characterized through X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma analysis (ICP). The physiochemically characterized nanocatalyst was tested for synthesis of 2,3-dihydroquinazolinones and higher yields of derivatives were obtained with less time duration. Moreover, the catalytic synthesis is easy to operate without the use of any kind of additives/bases. Furthermore, the catalyst was magnetically recoverable after the completion of the reaction and displayed reusability for six successive rounds without any loss in its catalytic efficiency (confirmed by XRD, SEM, and TEM of the recycled material) along with very low leaching of copper (2.12 ppm) and iron (0.06 ppm) ions. Also, the green metrics were found in correlation with the ideal values (such as E factor (0.10), process mass intensity (1.10), carbon efficiency (96%) and reaction mass efficiency (90.62%)).

RESUMEN

This work is generally focused on the synthesis of an efficient, reusable and novel heterogeneous Al2O3/CuI/PANI nanocatalyst, which has been well synthesized by a simple self-assembly approach where aniline is oxidized into PANI and aniline in the presence of KI also acts as a reductant. The nanocatalyst was well characterized by XRD, FTIR, SEM, EDX, TEM, BET and XPS techniques. In this study, the fabricated material was employed for the catalytic one-pot synthesis of 2-substituted benzimidazoles via condensation between o-phenylenediamine and aldehydes in ethanol as a green solvent. The present method is facile and offers several advantages such as high % yield, less reaction time, and no use of additive/bases. Also, the catalyst showed better values of green metrics including low E-factor: 0.17, high reaction mass efficiency: 85.34%, high carbon efficiency: 94%, and high process mass intensity: 1.17.

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RESUMEN

This work is mainly focused on the synthesis of an efficient and reusable heterogeneous Au/NiAlTi layered double hydroxide (LDH) nanocatalyst and its applications in the preparation of biologically important xanthene, 1,4-dihydropyridine, polyhydroquinoline, and 4H-pyran derivatives. NiAlTi LDH was designed hydrothermally and then gold was supported over the surface of LDH by using ion-exchange and NaBH4 reduction methods. The synthesized nanocatalyst was physicochemically characterized by X-ray diffractrometry, Fourier-transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and transmission electron microscopy (TEM). The TEM images confirmed the support of gold nanoparticles over the surface of LDH with a size distribution of 7-9 nm. The well-characterized nanocatalyst was tested for the synthesis of biologically important xanthene, 1,4-dihydropyridine, polyhydroquinoline, and 4H-pyran derivatives. The advantages obtained were excellent yields in a lesser reaction time. Stability and reusability were also accessed; the catalyst was stable even after five cycles. High catalytic efficiency, easy fabrication, and recycling ability of Au/NiAlTi LDH make it a potential catalyst for the synthesis of xanthene, 1,4-dihydropyridine, polyhydroquinoline, and 4H-pyran derivatives.

RESUMEN

This work is generally focused on the synthesis of NiFeTi-layered double hydroxides (LDHs) using a hydrothermal route, which were calcined at various temperatures (varying from 200 to 600 °C). The synthesized materials were physicochemically characterized. X-ray diffraction results revealed the loss of the layered structure on calcination resulting in the formation of layered double oxides (LDOs) or mixed metal oxides, which was also supported by Fourier transform infrared studies. Scanning electron microscopy results also show loss of the layered structure and the creation of LDOs on increasing the temperature. These LDOs were tested as the catalysts for the synthesis of biologically significant xanthene, 1,4-dihydropyridine, and polyhydroquinoline derivatives. Among all, NiFeTi LDH calcined at 600 °C proved to be the best catalyst for the synthesis of these derivative compounds under optimized conditions. The advantages obtained were excellent yields in a lesser reaction time. Stability and reusability were also assessed; the catalyst was stable even after five cycles. Furthermore, the memory effect of the obtained NiFeTi CLDH calcined at 600 °C confirms that the material so formed is a calcined state of LDH itself. High catalytic efficiency, easy fabrication, and recycling ability of NiFeTi CLDH calcined at 600 °C make it a potential catalyst for the synthesis of xanthene, 1,4-dihydropyridine, and polyhydroquinoline derivatives.

RESUMEN

The enormous increase of heavy metal pollution has led to a rise in demand for synthesizing efficient and stable adsorbents for its treatment. Therefore, we have designed a novel adsorbent by introducing (MoS4)2- moieties within the layers of NiFeTi LDH-NO3, via an ion exchange mechanism, as a stable and efficient adsorbent to deal with the increasing water pollution due to heavy metals. Characterization techniques such as XRD, FTIR, TGA, SEM, TEM, and Raman spectroscopy were used to confirm the formation of (MoS4)2- intercalated NiFeTi LDH and structural changes after the adsorption process. The efficiency of the material was tested with six heavy metal ions, among which it was found to be effective for toxic Pb2+ and Ag+ ions. When selectivity was studied with all six of the metal ions copresent in one solution, the material showed greater selectivity for Pb2+ and Ag+ ions with the selectivity order of Ni2+ < Cu2+ < Zn2+ < Fe3+ < Pb2+ < Ag+, with great adsorption capacities of 653 mg g-1 for Pb2+ and 856 mg g-1 for Ag+ metal ions. Further, the kinetics adsorption study for both the metal ions had a great correlation with the pseudo-second-order model and supported the chemisorption process via the formation of M-S bonding. The adsorption process obeyed the Langmuir model. Therefore, the MoS4-LDH material could be a promising adsorbent for the removal of heavy metals.

RESUMEN

OBJECTIVES: To determine the proportion of refractory status epilepticus (RSE) and super-RSE (SRSE) among patients with status epilepticus (SE) and to analyze RSE and non-RSE (NRSE) in terms of etiology and predictors for RSE. MATERIALS AND METHODS: Patients were identified from discharge summaries database with keywords of SE and records of the portable electroencephalogram (EEG) machine from January 2011 to March 2016. RESULTS: Two hundred and eighteen events were included in the study with 114 (52.3%) males, bimodal age preponderance age <5 years 30%, and second peak in age 15-65 years 52.8%, preexisting seizures were present in 34.4% (n = 75). Nearly 77.1% had NRSE (n = 168) and 22.9% had RSE (n = 50). This included 17 patients with SRSE (n = 17, 7.8% of all SE). Central nervous system (CNS) infection was a single largest etiological group in SE (69/218, 31.7%). In RSE, autoimmune encephalitis (17/50) and CNS infection (13/50) were the largest groups. De novo seizures (P = 0.007), low sensorium at admission (P = 0.001), low albumin at admission (P = 0.002), and first EEG being abnormal (P = 0.001) were risk factors on bivariate analysis. An unfavorable status epilepticus severity score (STESS) was predictive for RSE (P = 0.001). On multivariate analysis, de novo seizures (P = 0.009) and abnormal EEG at admission (P = 0.03) were predictive for RSE. CONCLUSIONS: Fifty patients had RSE (22.9%), of which 17 went on to become SRSE (7.8%). Unfavorable STESS score was predictive for RSE on bivariate analysis. On multivariate analysis, de novo seizures and abnormal initial EEG were predictors of RSE.