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991.
Sameh El Sayed Lluís Pascual Alessandro Agostini Ramón Martínez-Má?ez Félix Sancenón Ana M Costero Margarita Parra Salvador Gil 《ChemistryOpen》2014,3(4):142-145
The synthesis, characterization and sensing features of a novel probe 1 for the selective chromogenic recognition of diisopropylfluorophosphate (DFP), a sarin and soman mimic, in 99:1 (v/v) water/acetonitrile and in the gas phase is reported. Colour modulation is based on the combined reaction of phosphorylation of 1 and fluoride-induced hydrolysis of a silyl ether moiety. As fluoride is a specific reaction product of the reaction between DFP and the −OH group, the probe shows a selective colour modulation in the presence of this chemical. Other nerve agent simulants, certain anions, oxidant species and other organophosphorous compounds were unable to induce colour changes in 1. This is one of the very few examples of a selective detection, in solution and in the gas phase, of a sarin and soman simulant versus other reactive derivatives such as the tabun mimic diethylcyanophosphate (DCNP). 相似文献
992.
A number of novel, thiazole 5 , oxadiazole 6 , thiadiazole 7 , triazole 8 , 9 , and fused triazole derivatives 10 , 11 , 12 were obtained from a valuable and inexpensive fatty acids (stearic acid). Propoxylation of these compounds using 5 moles of propylene oxide produced nonionic surface active agents ( 13 , 14,15 16 , 17,18,19,20 ). The surface properties and the biodegradability of the latter compounds were evaluated. Some of the synthesized compounds were investigated for their antimicrobial activities. 相似文献
993.
Ahmed Badr Eldin Abdallah Shalaby Mahmoud Samy Abdallah Moataz Ahmed Shaldam Mohamed Adel Abdallah 《Arabian Journal of Chemistry》2019,12(7):1212-1218
Clonazepam contains one benzodiazepine ring in its chemical structure which makes it vulnerable to degradation. In this study, green analytical chemistry approach was applied in attempts for the development of validated stability indicating RP-HPLC method for determining clonazepam and its related substances in pharmaceutical formulation. Validation has been performed according to ICH guidelines. Assay was capable of simultaneous monitoring of the intact drug in the presence of its related substances within the same run. HPLC assay involved an ODS column and a mobile phase composed of 2% sodium dodecyl sulfate, 0.05 M sodium acetate buffer pH 3.5 and isopropanol in ratio (25:55:20) at a flow rate of 1.5 mL/min and detection was carried out at 254 nm. HPLC method allowed good resolution between the peaks that corresponded to the active pharmaceutical ingredients and its degradation products with good linearity, precision, accuracy, specificity, LOD and LOQ. The expanded uncertainty (0.33%) of the method was also estimated from method validation data. This analytical technique is not only ecofriendly but also faster than the conventional liquid chromatographic system official in the USP-36. 相似文献
994.
Summary A series of dioxouranium(VI) complexes with 7-carboxaldehyde-8hydroxyquinoline (oxine) and with some of its Schiff bases, LH, have been prepared and characterized by elemental analyses, electronic and vibrational spectral studies. All complexes except those of the oxine have the [UO2L2] · EtOH, stoichiometry (n=0, 1, 2 or 4). The uranyl complexes of the oxine have the formula [UO2L2(LH)]. The i.r. spectra reveal all ligands to be monobasic bidentate chelating agents coordinated to the uranium(VI)via the enolized phenolic OH and aldehydic oxygen or azomethine nitrogen atom. The force constant fU-o (mdyn Å) and the bond length rU-o (Å) of the U-O bond are also calculated and related to the electronic properties of thep-substituents. 相似文献
995.
Zofia Komsta Benjamin Mayes Adel Moussa Montserrat Shelbourne Alistair Stewart Andrew J. Tyrrell Laura L. Wallis Alexander C. Weymouth-Wilson Alexander Yurek-George 《Tetrahedron letters》2014
Synthesis of a novel 1′,2′-oxetane-uridine bearing a 2′-C-methyl substituent, [1-(1′,3′-O-anhydro-3′-C-methyl-β-d-psicofuranosyl)uracil], is described. Key to its construction was the use of 6-O-(p-toluoyl)-1,2:3,4-di-O-isopropylidene-3-C-methyl-d-psicofuranose as a nucleosidation substrate, which itself was derived from d-fructose. Anti-HCV activity was examined for the corresponding triphosphate which was not found to be an inhibitor of HCV NS5B 1b wild type polymerase in vitro. The 1′,2′-oxetane uridine triphosphate without 2′-C-methyl substitution was similarly inactive, however, the guanosine analog displayed modest inhibition (IC50 = 10 μM). 相似文献
996.
Najmeh Bashiri Sayed Javid Royaee Morteza Sohrabi 《Research on Chemical Intermediates》2018,44(1):217-229
Global warming, fossil fuel depletion and fuel price increases have motivated scientists to search for methods for the storage and reduction of the amount of greenhouse gases, especially CO2. The hydrogenation process has been introduced as an emerging method of CO2 capture and convertion into value-added products. In this study, new types of catalysts are introduced for CO2 hydrogenation and are compared based on catalytic activity and product selectivity. The physical properties of the samples are specified using BET. Iron catalysts supported on γ-Al2O3 with different metal promoters (X = Ni, K, Mn, Cu) are prepared through the impregnation method. Moreover, Fe–Ni catalysts supported on HZSM5-Al2O3 and Ce–Al2O3 are synthesized. Samples are reduced by pure H2 and involved in hydrogenation reaction in a fixed bed reactor (H2/CO2 = 3, total pressure = 10 MPa, temperature = 523 K, GHSV = 2000, 1250 nml/min). All catalysts provide high conversion in hydrogenation reactions and the results illustrate that the selectivity of light hydrocarbons is higher than that of methane and CO. It is found that Ni has a promoting effect on the conversion fluctuations throughout the reaction with 66.13% conversion. Using combined supported catalysts leads to enhancing catalytic performance. When Fe–Ni/γ–Al2O3—HZSM5 is utilized, CO2 conversion is 81.66% and the stability of the Fe–Ni catalyst supported on Al2O3 and Ce–Al2O3 furthey improves. 相似文献
997.
Optical supermicrosensor responses for simple recognition and sensitive removal of Cu (II) Ion target 总被引:1,自引:0,他引:1
The field of optical chemosensor technology demands a simple yet general design for fast, sensitive, selective, inexpensive, and specific recognition of a broad range of toxic metal ions. The suitable accommodation of chromogenic receptors onto ordered porous carriers have led to selective and sensitive chemosensors of target species. In this study, we offer real evidence on the potential use of two- and three-dimensional (2D and 3D) ordered supermicroporous monoliths as selective shape and size carriers for immobilizing the chromogenic probe. Among all the chemosensors, 3D supermicropore has exhibited easy accessibility of target ions, such as ion transports and high affinity responses of receptor-metal analyte binding events. This leads to an optical color signal that is easily generated and transduced even at trace levels of Cu(II) target ions. The supermicrosensors have shown the ability to create Cu(II) ion-sensing responses up to nanomolar concentrations (∼10−9 mol/dm3) with rapid response time (in the order of seconds). Supermicrosensors have the ability to create easily modified sensing systems with multiple regeneration/reuse cycles of sensing systems of Cu(II) analytes. The simple treatment using ClO4− anion as a stripping agent has removed effectively the Cu(II) ions and formed a “metal-free” probe surface. The supermicrosensors have exhibited the specificity behavior permitting Cu(II) ion-selective determination in real-life samples, such as in wastewater, despite the presence of active component species. Extensive analytical results indicate that the use of the supermicrosensor as Cu(II) ion strips for field screening can be a time- and cost-alternative tool to current effective laboratory assays. 相似文献
998.
A series of new functionalized 2-benzoylamino-5-hetaryl-1,3,4-oxadiazoles were efficiently synthesized via the reaction of the versatile key intermediates, 2-benzoylamino-5-cyanomethyl-1,3,4-oxadiazole (1) and N-(5-(5-amino-3-phenylamino)-1H-pyrazol-4-yl)-1,3,4-oxadiazol-2-yl)-benzamide (13), with some appropriate electrophilic reagents. The structures of the newly synthesized compounds were established on the basis of elemental analyses, spectral data, and by alternative synthesis wherever possible. The mechanisms of the studied reactions are discussed. Also, we evaluate the antioxidant activity of some representative examples of the newly prepared compounds. Among the synthesized compounds, 2-benzoylamino-5-cyanomethyl-1,3,4-oxadiazole (1) and N-(5-(7-methyl-5-oxo-2-(phenylamino)-4,5-dihydropyrazolo[1,5-a]pyrimidin-3-yl)-1,3,4-oxadiazol-2-yl)benzamide (17) showed excellent antioxidant activity and exhibited high protection against DNA damage induced by the Bleomycin iron complex. 相似文献
999.
Fatima Al‐Omran Adel Abou El‐Khair Rafat M. Mohareb 《Journal of heterocyclic chemistry》2002,39(5):877-883
Derivatives of 2‐aminothiophene‐3‐carbonitrile, 2‐thioxopyridine‐3‐carbonitrile, 1,8‐naphthyridine‐2‐one, thieno[2,3‐b]pyridine‐5‐carbonitrile and thieno[2,3‐d]pyrimidine incorporating with a 1H‐benzo‐triazole moiety or 1,3,4‐thiadiazole derivatives incorporating with a benzotriazol‐1‐ylmethyl group have been synthesized and tested for antimicrobial and antifungal activities. The structures of the newly synthesized compounds have been established on the basis of their analytical and spectral data. 相似文献
1000.
Essam Ezzeldin Muzaffar Iqbal Yousif A. Asiri Ahmed Y. A. Sayed Rashad Alsalahi 《Molecules (Basel, Switzerland)》2021,26(15)
Fostamatinib is a prodrug of the active metabolite tamatinib, which is a spleen tyrosine kinase (Syk) inhibitor used in the treatment of primary chronic adult immune thrombocytopenia and rheumatoid arthritis. A highly sensitive, rapid, reliable, and green method was developed and validated using ultra-performance liquid chromatography and tandem mass spectrometry (UPLC–MS/MS) for quantification of tamatinib in rat plasma. Ibrutinib was used as internal standard and liquid–liquid extraction was applied using tert-butyl methyl ether. The analyte was separated on an AcquityTM CSH C18 (2.1 mm × 100 mm, 1.7 µm) column using mobile phase consisting of 10 mM ammonium acetate and acetonitrile (10:90) and the flow rate was 0.25 mL/min. Electrospray ionization (ESI) was carried out in positive mode. Quantitation of tamatinib and the IS was performed using multiple reaction monitoring mode with precursor-to-product transitions of m/z 471.1 > 122.0 and m/z 441.1 > 84.0, respectively. The calibration range was 0.1–1000.0 ng/mL and the linearity of the method was ≥0.997. The developed method greenness was investigated. All principal parameters for the method, including linearity, accuracy, precision, recovery, and stability, were within acceptable ranges. Tamatinib pharmacokinetic study in rats was successfully carried out using the developed method. 相似文献