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91.
M. A. Salem M. H. Helal M. A. Gouda Y. A. Ammar M. S. A. El-Gaby S. Y. Abbas 《合成通讯》2018,48(13):1534-1550
Coumarins units have recently emerged as a hot topic of research due to their diverse applications. Their synthesis is partly based on classical methodologies such as Pechmann reaction or Knoevenagel condensation, but it also sparked the discovery of completely new pathways. In very recent years so-called vertically expanded coumarins were synthesized, effectively expanding the portfolio of existing architectures. This review serves as a guide through synthesis strategies to coumarins. 相似文献
92.
[reaction: see text]. Commercially available cyanoethyl phosphoramidites derived from T, d(C), d(A), and d(G) were hydrolyzed (1H-tetrazole, MeCN/H2O) to give the corresponding H-phosphonates in excellent yields. Palladium(0)-catalyzed cross-coupling of each of these with the thymidine-derived vinylbromide 2 afforded the corresponding vinylphosphonate-linked dimers TT, d(C)T, d(A)T, and d(G)T in modest to good yields. The TT dimer was further elaborated to give a 5'-DMT-TT-3'-CEP building block, and this was used in the automated synthesis of the TpTTpT tetramer. 相似文献
93.
Zeinab Ansari-Asl Tahereh Sedaghat Abbas Tarassoli Hossein Motamedi Elham Hoveizi 《Phosphorus, sulfur, and silicon and the related elements》2017,192(5):538-543
Three new water-soluble organotin complexes R2Sn(5-BrSalGT)Cl [R = Ph, Me] and Ph2Sn(2-OHNaphGT)Cl have been synthesized by the reaction of R2SnCl2 (R = Ph or Me) with Schiff bases derived from condensation of Girard-T reagent with 5-bromosalicylaldehyde and 2-naphthaldehyde, (5-BrH2SalGT)Cl (1) and (2-OHH2NaphGT)Cl (2). The synthesized compounds have been investigated by elemental analysis, conductometric measurements, IR, 1H NMR, and 119Sn NMR spectroscopy. These data show that the deporotonated ligand is coordinated to Sn(IV) via ONO atoms and six-coordinate zwitterionic complexes are formed. The ligands and their complexes were investigated for their in vitro toxicity against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. The results show remarkable antibacterial activity against the studied bacteria. All complexes exhibit more inhibitory effects than the parent ligand. The anticancer activity of all compounds were also performed on HN5 cell line and (2-OHH2NaphGT)Cl with concentration of 1 mg mL?1 was found to show higher anticancer activity than other compounds. 相似文献
94.
95.
Niyaz Ahmad Rizwan Ahmad Atta Abbas Naqvi Md Aftab Alam Mohammad Ashafaq Zeenat Iqbal 《液相色谱法及相关技术杂志》2017,40(3):133-146
The study reports a rapid and short analytical technique for separation, characterization, and quantitation along with comparative pharmacological effect of curcuminoids in cerebral ischemia. Flash chromatography, using silica and diol columns along with gradient mobile phase, was utilized to separate three curcuminoids, i.e., curcumin (Cur), demethoxycurcumin (DMC), and bisdemethoxycurcumin (BDMC) for the first time. The separated peaks were monitored at 200–360?nm, whereas the purity of compounds (96.2–97.6%) was determined through qualitative analysis such as infrared and 1H and 13C-nuclear magnetic resonance spectroscopy, mass spectrometry (MS), and differential scanning calorimetry. Furthermore, chitosan nanoparticles (CS-NPs) for curcuminoids were prepared and characterized through zeta sizer, zeta potential, scanning electron microscopy, and transmission electron microscopy. The developed ultra performance of liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry/mass spectrometry (UPLC-ESI-Q-TOF-MS/MS) method showed simplified automation and shorter run time for Combi flash over conventional separation techniques. The CS-NPs for all the three curcuminoids and combined-curcuminoids (CCr) (combined and administered together for a synergistic effect), following intranasal administration in middle cerebral artery–occluded rats were evaluated for grip strength, locomotor activity, and histopathological examination where the anti-ischemic activity was observed, in terms of potency, for all three CS-NPs and CCr as CCr>Cur>DMC>>BDMC. Cur-CS-NPs exhibited more potency among Cur, DMC, and BDMC, whereas CCr was the more potent anti-ischemic drug compared to Cur, DMC, and BDMC. For Cur the characteristic activity is proposed because of the presence of methoxy group on the phenyl ring whereas for CCr it is synergistic effect of curcuminoids. 相似文献
96.
Nafise Modanlou Juibari Abbas Eslami 《Journal of Thermal Analysis and Calorimetry》2017,128(3):1327-1334
This work aimed the evaluation of pH influence in the obtainment of composites from palygorskite (PAL) and chitosan (CS). The materials PAL/CS-1 and PAL/CS-2 were obtained by similar methodology with modified pHs: 5.0 ± 0.5 and 11.0 ± 0.5, respectively. Both materials were evaluated for specific surface area analysis, elemental analysis, XRD, FTIR, thermal analysis, MEV and interaction drug composite, using 5-aminosalicylic acid (5-ASA) as model. The surface area analysis data showed the reduction in PAL/CS-2 related to CS presence on surface in contrast with PAL/CS-1, which corroborate with elemental analysis present nine times more of CS in PAL/CS-2 composition. Regarding to XRD data, the interaction of CS with PAL did not cause modification in clay structure in PAL/CS-2. These results were confirmed by FTIR data with the N–H deformation vibration in PAL/CS-2 while PAL/CS-1 was invariable to PAL. In thermal analysis, results were observed 60.2% residual mass to PAL/CS-2, which it was lower than PAL (87.2%) and PAL/CS-1 (86.7%), due to CS decomposition which had enthalpy energy of 62.1 J g?1 K?1, confirming the data previously cited. PAL/CS-2 presented 5-ASA adsorption of 7.9 mg g?1, which was inferior to others probably caused by scarcity of active sites of PAL already occupied by CS. These results showed that pH control was fundamental to enhance efficiency of obtainment of composite in basic pH because the decrease in CS protonation degree increasing interaction between this one and PAL, although it contributed to decrease in 5-ASA adsorption due to low availability of interaction sites. 相似文献
97.
Shabbir Hussain Saira Shahzadi Muhammad Shahid Asif Ali Tahir Syed Mustansar Abbas 《Journal of Coordination Chemistry》2017,70(24):4070-4092
Bimetallic chlorodi-/triorganotin(IV) derivatives of general formulas R2(H2O)SnLCSSSn(Cl)R2 (R=Me: 1; Ph: 2) and R3Sn(Na)LCSSSnR3·H2O (R=Bu: 3; Ph: 4) were prepared by reaction of iminodiacetic acid disodium salt hydrate (Na2LH) with CS2 and R2SnCl2/R3SnCl in methanol. The reaction between Na2LH, CS2, and PdCl2 produced [Na2LCSS]2Pd·2H2O (5) which was treated with R3SnCl to synthesize the heterobimetallic derivatives [R3Sn(Na)LCSS]2Pd·2H2O (R=Me: 6; Ph: 7). The complexes were characterized by microanalysis, spectroscopic, and thermogravimetric analyses. Elemental analysis data, mass fragmentation, and thermal degradation patterns supported the molecular composition of the complexes. FT-IR data indicated monodentate binding of carboxylate while a chelating coordination mode of the dithiocarboxylate was verified in the solid state. A five-coordinate tin(IV) was demonstrated in the solid state. In solution, a tetrahedral/trigonal bipyramidal configuration around Sn(IV) and a square planar geometry of Pd(II) was indicated by multinuclear NMR (1H and 13C) and UV-visible studies. The Pd(II) derivatives showed interaction with salmon sperm-DNA and caused an inhibition of alkaline phosphatase (ALPs). The antibacterial/antifungal potential of the coordination products varied with the nature of incorporated metal and a substitution pattern at tin(IV); the palladium metallation decreased the antimicrobial activities. The triorganotin(IV) products exhibited more powerful action against bacteria/fungi as compared to their diorganotin(IV) counterparts. The complexes displayed sufficiently lower hemolytic effects in vitro as compared to triton X-100 and slightly higher than PBS. 相似文献
98.
A series of alkyl triazole glycoside surfactants, ATGs, differing in the length of the alkyl linker between the sugar and the triazole, was synthesized and investigated on their surfactant properties and phase behavior in water. The results indicate no significant impact of the linker on surface and interphase properties, whereas the phase behavior is affected. Higher affinity for the bicontinuous cubic phase potentially favors methylene-linked ATGs over higher homologs for drug-delivery applications. A comparison of glucose and xylose reveals a tendency for high Krafft points for propargyl xyloside based ATGs. This disfavors these surfactants with respect to both glucose analogs and higher homologs. 相似文献
99.
Elham Masoudipour Soheila Kashanian Abbas Hemati Azandaryani Kobra Omidfar Elham Bazyar 《Cellulose (London, England)》2017,24(10):4217-4234
Storage conditions seem to be important in the long-term stability of nanoparticles (NPs). This work studies the effects of surfactants and storage container on particle size distribution and zeta potential during long-term storage of acid hydrolyzed potato starch NPs. The NPs were prepared from potato starch using acid hydrolysis and high-intensity ultrasonication. During the ultrasonic treatment, the surfactants were added dropwise to the solutions to reduce the size and stabilize the formed NPs. Particle size distribution, zeta potential, and FE-SEM were used to characterize the ensuing NPs. Additionally, a 5-month stability study was performed to evaluate the maintenance of potato starch NPs over time at different storage conditions. Then, NPs from corn starch were produced by the same procedure and were used for preparing pH-responsive nanocarriers containing NaHCO3 for delivery of an anti-cancer drug, FTY720. These NPs were able to release the drug at pH 5.0 because of CO2 generated from NaHCO3 in acidic pH and released from the NPs by the production of pores, which accelerate drug release. 相似文献
100.