Research on Chemical Intermediates最新文献

This study aimed to explore the extracts of Castanea mollissima Blume, 1851 as rich sources of enzyme inhibitors targeting type 2 diabetic (T2D) drugs. It was proved that the enzyme inhibitor with moderate effect against α-amylase and high inhibition against α-glucosidase may be a potential candidate for T2D management. Among the parts used of C. mollissima, the trunk bark extract demonstrated moderate pancreatic α-amylase inhibitory activity and a high inhibitory effect against α-glucosidase from rat with the IC₅₀ inhibition values of 371.23 and 212.79 μg/mL, respectively. Acarbose—a commercial antidiabetic compound with testing IC₅₀ of 24.01 and 192.35 μg/mL against α-amylase and α-glucosidase, respectively. Notably, the potent mammalian α-glucosidase inhibitory effect of the C. mollissima trunk bark extract collected in Vietnam was reported for the first time. Nineteen compounds (named 1–19) were detected and identified from the C. mollissima trunk bark extract using GCMS and HPLC analyses. Based on GCMS analysis, 9 volatiles were identified (1–9), of these, compounds 1, 4, and 9 were found as major volatiles with areas of 11.44, 13.5 and 45.27%, respectively. The utilization of HPLC techniques resulted in the detection and identification of 3 phenolic (10, 12, 15) and 7 flavonoid compounds (11, 1 3, 14, 16, 17, 18, 19). Of these, compounds 11, 12, 13, 14, 15, and 17 were found to contain in the C. mollissima trunk bark extract with high contents of 120.734, 40.373, 79.826, 43.845, 57.933, and 19.145 μg/mg of dried extract, respectively. The docking result indicated that most major compounds (1, 4, 9, 11, 12, 14, and 17) showed effective binding to α-glucosidase with good binding energy and acceptable RMSD values. In addition, almost all the identified compounds possessed drug properties and showed non-toxic for human use via Lipinski’s rule of five and ADMET analyses.

Herein, we have synthesized copper oxide nanoparticles (CuONPs) using an aqueous pod extract of Acacia concinna (A. concinna) and analyzed their catalytic activities. The phytochemicals in the pod extract of A. concinna were used as a reducing and stabilizing agent and CuSO₄·7H₂O as a precursor for forming CuONPs. The biosynthesized CuONPs were characterized using UV–visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FT-IR), field emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscope (HR-TEM) for structural and morphological analysis. The synthesis of CuONPs was confirmed by the UV absorption peak at 330 nm and XRD analysis. TEM analysis has been representing the CuO nanospheres with an average size of 29 nm. The newly synthesized CuONPs exhibit greater antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The highest efficacy of biosynthesized CuONPs (200 µg/mL) was observed against S. aureus with a 36.5 mm zone of inhibition. Biosynthesized CuONPs are a basic, highly efficient, heterogeneous, and green recyclable catalyst for the multicomponent synthesis of 4H-benzo[b]pyran derivatives. Tetra-hydrobenzo[b]pyran derivatives can be synthesized through a three-component reaction involving an aldehyde, malononitrile, and either 1,3-cyclohexanedione or 5,5-dimethyl-1,3-cyclohexanedione, conducted at room temperature. This synthetic method provides several advantages such as simple work-up procedures, short reaction time, minimal byproducts, and high yields of products.

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This study includes the synthesis of 11 different calixarene derivatives, the preparation of thin film sensors on quartz crystal microbalance (QCM) crystals, and the specification of sensor-analyte pairs by examining the sensing properties of these sensors against different phenolic compounds such as p-nitrophenol (PNP), phenol (PHE), p-chlorophenol (PCP), and m-nitrophenol (MNP) in the aqueous medium. For this purpose, calixarene derivatives with different structures were first synthesized and characterized using spectroscopic methods such as Proton nuclear magnetic resonance (¹H-NMR) and Fourier-transform infrared spectroscopy (FTIR). Detection studies were carried out for proposed phenolic compounds with calixarene-based QCM sensors obtained by electrospinning. At the beginning of the experiments, sensor-analyte pairs were determined according to the values at which the highest sensor frequencies were observed. Therefore, according to the highest sensor responses towards 5 × 10^–5 M analytes, the sensor-analyte pairs were determined as QCM-5 for PNP (17.8 Hz) and MNP (3.8 Hz). Also, for PHE and PCP, the highest responses were observed as 4.1 Hz and 4.0 Hz in the QCM-11 and QCM-1 sensors, respectively. In further experiments, determined sensor-analyte pairs were tested at different analyte concentrations. In addition, the limits of detection (LOD) of the sensors were calculated from different analyte concentration studies such as 0.580 (QCM-5), 0.659 (QCM-11), 0.490 (QCM-1), and 0.466 (QCM-5) mM against PNP, PHE, PCP, and MNP, respectively. Interactions between sensor-analyte pairs were evaluated in terms of adsorption kinetics. It was observed that the relationships between the sensor responses and the analyte concentration were highly consistent with the Freundlich isotherm. In addition, repeatability and stability tests of the sensors were performed, and it was observed that they exhibited good repeatability and stability properties. Finally, selectivity between analytes was assessed, and the highest selectivity was observed as with the QCM-4 sensor versus p-nitrophenol. It was found that the selectivity of the sensor to PNP was 21.1 times compared to PHE and PCP and 74 times compared to MNP.

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Three pyrrolo[3, 2-b]pyrrole compounds (Py–CF₃–H, Py–CF₃–CH₃ and Py–CF₃–OCH₃) were prepared as radical photoinitiators for visible light radical photopolymerization. Radical photopolymerization using the Py–CF₃–H initiator-induced TMPTA system achieved a peak conversion rate of 72% for C=C double bonds. The effect of changes in the electronic structure on the photoinitiation ability of the three photoinitiators was studied using spectroscopic measurements and theoretical calculations. The generated free radicals were detected using electron paramagnetic resonance (EPR). The synthesized photoinitiators matched the 405 nm LED. Under steady photolysis at 405 nm, the maximum absorption peaks decreased rapidly after exposure to light, and a new blue-shifted peak appeared. The end groups on the phenyl at 1,4 positions of the pyrrolo[3,2-b]pyrrole core considerably influenced the charge surrounding the central core, according to the electrostatic potential (ESP) results. The –H on 1,4-phenyl provides a less negative charge on the fused pyrrole core compared to the –CH₃ and –OCH₃. Thus, this work provides an experimental foundation for investigating pyrrole-based photoinitiators in polymer curing.

A copper coordinated L-ascorbic acid (Cu@AACP) metal–organic framework was synthesized and characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), atomic absorption spectroscopy (AAS), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), wavelength dispersive X-ray spectroscopy (WDX), X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS). The BET method was used to investigate the textural characteristics of Cu@AACP, including surface area, pore diameter and total pore volume. The SEM analysis was used to investigate the morphology and size of Cu@AACP particles. AAS, WDX and EDS techniques were used to investigate the elemental content of Cu@AACP. The TGA analysis was used to investigate the presence of solvents or moisture, thermal stability and organic–inorganic content of catalyst. The FT-IR spectroscopy was used to the characterization of functional groups in the structure of the materials. The XRD pattern was used to investigate the crystalline phase of the catalyst. The results of the analyses confirmed the successful synthesis of copper MOF of L-ascorbic acid (Cu@AACP). The catalytic performance of Cu@AACP was examined in synthesizing of 2, 3-dihydroquinazolin-4(1H)-ones (through condensation of aldehydes and anthranilamide in ethanol at 80 °C) and polyhydroquinolines (through condensation of aldehydes, dimedone, ammonium acetate and ethyl acetoacetate in ethanol at 80 °C). The reaction conditions for the synthesis of 2, 3-dihydroquinazolin-4(1H)-ones and polyhydroquinolines were optimized, where the best results were obtained in ethanol solvent at 80 °C in the presence of 6 mg of Cu@AACP as catalyst. The results show that an improved product yield is obtained between 84 and 95%. Recycle test of the catalyst confirmed that the heterogeneous catalyst exhibited good catalytic stability, efficiency and very high activity in successive runs because of its unique pore network. To show the stability of Cu@AACP nanocatalyst after recycling, the recovered catalyst was characterized by AAS, FE-SEM, EDS and FT-IR techniques.

The methanol-to-olefins (MTO) process is a promising method for producing light olefins, which are essential intermediates in petrochemical processes. SAPO-34, a crucial catalyst for the MTO process, often suffers from compromised quality when synthesized using low-cost precursors. This study presents a novel and efficient gel preparation method to enhance the performance of amine-templated SAPO-34. Comprehensive characterization through XRD, SEM, EDX, XRF, N₂ physisorption, and FTIR analyses provided insights into the catalyst structure and composition. The results exhibit promoting nucleation, crystal growth, and silica incorporation while suppressing impurities. Notably, increased silica incorporation led to the formation of crystal cracks, significantly boosting the specific surface area. The optimized SAPO-34 catalyst exhibited improved catalytic performance, characterized by a short induction period and a sustained high light olefin selectivity of 84% for over 6 h, showcasing the potential of this approach for producing cost-effective, high-performance MTO catalysts.Kindly check and confirm the corresponding author of the article and the first/last name of the authors are correctly identifiedYes. The corresponding author of the article and the first/last name of all authors are correct.

Developing high-performance catalysts for NO_x reduction was a significant challenge. CWK catalysts modified with iron sources were synthesized using co-precipitation and impregnation methods. The CWK-F₃C and CWK-F₃S catalysts exhibited the superior catalytic activity at 250–350 ℃ and the excellent N₂ selectivity. The key reasons for the enhanced catalytic activity of CWK-F₃C and CWK-F₃S catalysts could be attributed to the higher Fe³⁺ concentration, more surface chemisorbed oxygen species and bigger relative fraction of Ce³⁺. More significantly, the adsorption of NH₃ and redox capability were both strengthened by the Fe³⁺ doping. The DRIFTS experiment results showed that the E-R and L–H mechanism were followed by CWK-F₃C and CWK-F₂C catalysts. Furthermore, the introduction of Fe³⁺ generated more surface acidic sites, which could facilitate the formation of key intermediates (-NH₂) (NH_3(ads) + O_(ads)/O²⁻(ads) → -NH_2(ads) + -OH_(ads)). The presence of Fe³⁺ was conducive to NO₃⁻ formation (NO₃⁻ + NO_(ads) → NO_2(ads)), resulting in the presence of fast reaction, causing the excellent low temperature catalytic performance. Hence, the production of -NH₂ and NO₃⁻ species was responsible for the outstanding catalytic activity of CWK-F₃C.

In this study, tetradecyl methacrylate-maleic anhydride-benzylidene acetone (C₁₄MC-MA-MCA) terpolymers were synthesized via free radical polymerization and evaluated as pour point depressants (PPDs) for coal-based diesel. The findings indicate that the C₁₄MC-MA-MCA (3:1:1) terpolymer exhibited the most effective inhibition of the solid point (SP) at 1500 ppm concentration. Specifically, it reduced the SP of coal-based diesel from − 4 to − 42 °C, marking a significant decrease of 38 °C. Furthermore, the crystallization behavior and SP reduction mechanism of C₁₄MC-MA-MCA in coal-based diesel were investigated using viscosity analysis and polarized optical microscopy (POM).

Mesoporous silicas of MCM-41 and MCM-48 types were synthesized and modified with copper by template ion-exchange (TIE) technique. A high dispersion of deposited copper species was managed by subsequent treatment of the samples with ammonia, urea, or acetonitrile solution. Copper-modified silicas were analysed in terms of their chemical composition (ICP-OES), ordering of porous structure (XRD), textural parameters (low-temperature N₂ sorption), dispersion and form of introduced copper species (UV–vis-DR, XRD, H₂-TPR, NH₃-TPD). Mesoporous silicas modified with copper exhibited promising catalytic efficiency in selective catalytic reduction of NO with ammonia (NH₃-SCR). The samples containing dispersed copper species (predominantly monomeric copper cations) presented enhanced catalytic activity compared to catalysts containing CuO aggregates. On the other hand, CuO aggregates showed greater catalytic activity in the side process of direct ammonia oxidation by oxygen present in the reaction mixture. It was demonstrated that TIE post-treatment of the samples with urea resulted in most effective improving dispersion of deposited copper and is less destructive for ordered porous structures of mesoporous silica comparing to treatment with ammonia solution.

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We report a novel magnetic ionic liquid (MIL) based on pyridine successfully prepared by a two-step reaction pathway. The prepared MIL was recognized by means of Fourier transform infrared spectroscopy (FT-IR), UV–visible and Raman spectroscopies, thermal analysis (TGA and DTG), magnetic susceptibility measurement, mass spectra (MS), proton NMR ((^{1}hbox {H},hbox {NMR})), carbon NMR ((^{13}hbox {C},hbox {NMR})), Hammett acidity, and CHN elemental analysis. The MIL was shown to be efficient in the synthesis of xanthenediones under solvent-free conditions. In addition, the antibacterial and antifungal activity of the MIL was investigated.