thiourea and naphthalene

A thiourea-based fluorescent chemosensor NADA, (E)-2-(4-(diethylamino)-2-hydroxybenzylidene)-N-(naphthalen-1-yl)hydrazine-1-carbothioamide, has been designed and synthesized. NADA could detect Ga

Topics: Density Functional Theory; Fluorescent Dyes; Gallium; Limit of Detection; Models, Molecular; Molecular Conformation; Naphthalenes; Spectrometry, Fluorescence; Thiourea

Two series of novel naphthalin-containing pyrazoline derivatives C1-C14 and D1-D14 have been synthesized and evaluated for their EGFR/HER-2 inhibitory and anti-proliferation activities. Compound D14 displayed the most potent activity against EGFR and A549 cell line (IC(50)=0.05 μM and GI(50)=0.11 μM), being comparable with the positive control Erlotinib (IC(50)=0.03 μM and GI(50)=0.03 μM) and more potent than our previous compounds C0-A (IC(50)=5.31 μM and GI(50)=33.47 μM) and C0-B (IC(50)=0.09 μM and GI(50)=0.34 μM). Meanwhile, compound C14 displayed the most potent activity against HER-2 and MCF-7 cell line (IC(50)=0.88 μM and GI(50)=0.35 μM), being a little less potent than Erlotinib (IC(50)=0.16 μM and GI(50)=0.08 μM) but far more potent than C0-A (IC(50)=6.58 μM and GI(50)=27.62 μM) and C0-B (IC(50)=2.77 μM and GI(50)=3.79 μM). The docking simulation was performed to analyze the probable binding models and the QSAR models were built for reasonable design of EGFR/HER-2 inhibitors at present and in future. The structural modification of introducing naphthalin moiety reinforced the combination of our compounds and the receptor, resulting in progress of bioactivity. Moreover, the replacement of thiourea skeleton by using benzene ring resulted in the slight diversity of the two series towards specific targets.

Topics: Antineoplastic Agents; Binding Sites; Cell Line, Tumor; Cell Survival; Crystallography, X-Ray; Drug Design; ErbB Receptors; Erlotinib Hydrochloride; Humans; MCF-7 Cells; Molecular Conformation; Molecular Docking Simulation; Naphthalenes; Protein Structure, Tertiary; Pyrazoles; Quantitative Structure-Activity Relationship; Quinazolines; Receptor, ErbB-2; Thiourea

The thiourea based receptor containing naphthalene groups (1), has been successfully designed and synthesized for application as an oxalate receptor. A density functional theory at B3LYP/6-31G(d,p) level of theory has been applied to predict the binding ability between 1 and selected anions, i.e., oxalate, malonate, succinate, glutarate, dihydrogen phosphate, and hydrogen sulphate. Calculation results point out that receptor 1 shows the strongest interaction to oxalate ion with the binding free energy of 172.48 kcal mol(-1). The recognition ability of 1 to the selected anions has been also investigated by means of the absorption and emission techniques. Experimental results are in excellent agreement with the calculation data in which receptor 1 shows highly selective for oxalate ion over the other anions with logbeta of 3.82 (0.02) M(-1) by means of the size of binding cavity.

Topics: Biosensing Techniques; Fluorescence; Molecular Structure; Naphthalenes; Oxalates; Thiourea

Fabrication of porous frits to retain stationary phases is a critical issue in column preparation for capillary electrochromatography (CEC). In this work, porous frits were prepared by applying an external magnetic field to magnetically responsive particles placed inside a fused-silica capillary. Three batches of uniform magnetite spheres with particle diameters of 0.3, 0.4, and 0.6 microm and saturation magnetization values of 73.03, 74.41, and 77.83 emu/g, respectively, were used as frit particles and octadecyl- and phenyl-bonded silica gels were packed successfully into frit-containing capillaries. The performance of the resulting magnetically immobilized frits and packed columns was evaluated. The electroosmotic mobilities in capillaries containing outlet frit only were found to be reduced by 2-4% whereas the plate heights of an unretained marker increased by 30-50% as compared to those in open capillaries. These variations are believed to be associated with the inhomogeneities of the packed structure of the frits. The magnetically immobilized frits showed adequate mechanical strength to withstand the flow drag force, allowing separation in capillaries packed with 5-mum stationary phases up to 10-15 cm, thus rendering column efficiency and reproducibility comparable with those obtained with sintered frits. Taken together, retaining frits made of uniform magnetite particles serves as a viable alternative to sintered frits for column preparation, which offers several distinct advantages such as ease of preparation, improved durability as compared to sintered frits where the removal of the polyimide coating makes the packed column susceptible to breakage, and use of large-bore capillaries for semipreparative separations.

Topics: Anthracenes; Capillary Electrochromatography; Ferrosoferric Oxide; Fluorenes; Magnetics; Microspheres; Naphthalenes; Reproducibility of Results; Thiourea; Toluene

A series of bicyclic analogues having indan and tetrahydronaphthalene templates in the A-region were designed as conformationally constrained analogues of our previously reported potent TRPV1 antagonists (1, 3). The activities for rat TRPV1 of the conformationally restricted analogues were moderately or markedly diminished, particularly in the case of the tetrahydronaphthalene analogues. The analysis indicated that steric constraints at the benzylic position in the bicyclic analogues may be an important factor for their unfavorable interaction with the receptor.

Topics: Animals; Bridged Bicyclo Compounds, Heterocyclic; Indans; Molecular Conformation; Naphthalenes; Rats; Structure-Activity Relationship; Thiourea; TRPV Cation Channels

Octadecylamine-capped gold nanoparticles (ODA-Au-NPs) were prepared and characterized by using UV-Vis adsorption spectrum, transmission electron chromatography (TEM), SEM, and FT-IR. A simple but robust hydrophobic coating was easily developed by flushing a capillary with a solution of ODA-Au-NPs, because the positive charges were carried by the nanoparticles which strongly adsorb to the negatively charged inner surface of a fused-silica capillary via electrostatic and hydrophobic interactions. The chromatographic characteristics of the coated capillary was investigated by varying the experimental parameters such as buffer pH, buffer concentration, and percentage of organic modifier in the mobile phase. The results show that (i) resolution between thiourea and naphthalene is almost the same when comparing the electrochromatograms obtained using pH 7 buffer as mobile phase after and before the capillary column was operated using pH 11 and 3 mobile phase; (ii) no significant changes in retention time and deterioration in peak efficiency were found after 60 runs of test aromatic mixtures; and (iii) column efficiency up to 189 000 theoretical plates/meter for testosterone was obtained. All of the results indicated that the coating could act as a stable stationary phase for open tubular CEC as well as for bioanalysis.

Topics: Amines; Capillary Electrochromatography; Gold; Hydrophobic and Hydrophilic Interactions; Metal Nanoparticles; Nanotechnology; Naphthalenes; Static Electricity; Thiourea

Butyl-methacrylate-based porous monoliths were prepared inside fused-silica capillaries as reversed-phase separation media for liquid chromatography (LC) and capillary electrochromatography (CEC). During our previous research on methacrylate-based monoliths for reversed-phase separations, we noticed that a separation efficiency of up to 300,000 plates/m can easily be obtained in the CEC mode for unretained compounds. However, the efficiencies for retained compounds were much lower in reversed-phase systems, especially in pressure-driven LC. In this work methacrylate-based columns were prepared and characterized in terms of efficiency and retention in reversed-phase (pressure-driven) LC and in CEC. Much attention has been paid to the mass-transfer mechanism in the stationary phase. Factors that affect the plate heights for specific compounds have been investigated. A possible explanation for the relatively low separation efficiency of retained compounds and suggestions to improve molecular mass transfer are provided.

Topics: Benzene; Capillary Electrochromatography; Chromatography, Liquid; Methacrylates; Naphthalenes; Permeability; Polymers; Temperature; Thiourea; Viscosity

Nonporous silica spheres (1 microm) were synthesized and bonded with octadecylsilane functionality. These stationary phase particles were packed electrokinetically into fused-silica capillaries with 100 microm id for a length of 20 cm, which was evaluated by using pressurized CEC (pCEC). The efficiency of the C18 RP column was characterized through the theoretical plates of thiourea, benzyl alcohol, toluene, styrene, and naphthalene. The effects of experimental parameters such as the applied voltage, sample size, pump flow rate, pH value and the concentration of the buffer solution, and the content of methanol in the mobile phase, on-column efficiency were evaluated. Column efficiency as high as 200 000 theoretical plates per meter for naphthalene was obtained with the optimal condition of 70% v/v methanol and 30% v/v of 10 mmol/L phosphate buffer (pH 7.8) at an applied voltage of 10 kV and a supplementary pressure of 500 psi.

Topics: Benzyl Alcohol; Buffers; Capillary Electrochromatography; Hydrogen-Ion Concentration; Naphthalenes; Reproducibility of Results; Silanes; Silicon Dioxide; Styrene; Thiourea; Toluene

In this study, the sorption behavior of a wide variety of N-, S-, and O-heterocyclic compounds (NSOs) to reference soils (Eurosoils 1-5) was characterized by a soil column chromatography (SCC) approach. The major goal was to identify the compound specific and environmental factors influencing sorption processes. The sorption of S- and O-heterocyclic compounds (thiophene, benzothiophene, 5-methylbenzo[b]thiophene, benzofuran, 2-methylbenzofuran, and 2,3-dimethylbenzofuran) was generally controlled by nonspecific interactions with soil organic carbon (OC). With regard to non-ionizable N-heterocyclic compounds, pyrrole, 1-methylpyrrole, and pyrimidine were hardly retarded in any soil. The sorption of indole, 2-hydroxyquinoline, and benzotriazole was dominated by specific interaction (e.g., complexation of surface-bound cations) rather than partition to soil OC. The sorption of ionizable N-heterocyclic compounds (quinoline, isoquinoline, quinaldine, 2-methylpyridine, and pyridine) can be described by a conceptual model including partitioning to soil OC, cation exchange, and an additional sorption process (probably surface complexation of the neutral species). Cation exchange was usually the dominant mechanism in the sorption of ionizable compounds if the protonated fraction of the compound exceeded 5%. Otherwise, surface complexation became dominant. Soil pH was the most important factor influencing the sorption of ionizable NSOs. Our study suggests that a fairly precise assessment of sorption in most soils can be expected for N-, S-, and O-heterocyclic compounds if the three sorption mechanisms are taken into accountwhere appropriate. Deviations from this behavior indicated special cases where additional soil specific properties (e.g., accessible surface, CEC, charge density) need to be considered such as for 2-methylpyridine and pyridine sorption to Eurosoil 1.

Topics: Adsorption; Benzene; Chromatography, High Pressure Liquid; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds, 2-Ring; Hydrogen-Ion Concentration; Naphthalenes; Phenol; Soil Pollutants; Thiourea; Toluene

We describe the novel use of water-in-oil (W/O) microemulsions to achieve unique separations in microemulsion electrokinetic chromatography (MEEKC). The choice and concentration of the buffer type, surfactant and co-surfactant were all examined and optimized. Separations of a range of neutral and acidic analytes was shown to be markedly different to that obtained by (oil-in-water) O/W MEEKC. Neutral solutes are separated by virtue of their solubility (log P) values in O/W MEEKC with the more water-insoluble solutes migrating last. This separation process does not occur in W/O, as neutral solutes are not separated in order of log P.

Topics: Acetophenones; Buffers; Caffeine; Chromatography, Micellar Electrokinetic Capillary; Emulsions; Hydrogen-Ion Concentration; Naphthalenes; Oils; Pharmaceutical Preparations; Solubility; Sorbic Acid; Surface-Active Agents; Temperature; Thiourea; Water

The separation mechanism for neutral solutes on a cyano column in capillary electrochromatography (CEC) was investigated and the effects of components of mobile phases and the kinds of buffers on retention of samples were studied. In comparing the separation behavior of samples on CN column with reversed-phase ODS column and normal phase SI column, the peak order was different on CN column under different experimental conditions, and the characteristics of CN column having both reversed and normal phase mechanisms were obvious. The migration velocities for neutral solutes of different polarity on CN column were very different by the effects of two mechanisms under different operating conditions. It is easy to change peak order and to adjust selectivity.

Topics: Benzyl Alcohol; Cyanides; Electrochemistry; Electrophoresis, Capillary; Mechanics; Naphthalenes; Solutions; Thiourea

Reversed-phase nonporous silica (RP-NPS) of 1.5 microm dp is employed to demonstrate rapid and efficient separations in packed capillary electrochromatography (CEC). Two methods for packing capillaries and two techniques to manufacture frits used to hold the packing in place are evaluated for their effect upon separation performance using polyaromatic hydrocarbons (PAHs) and polar neutral pharmaceutical compounds. Attention is given to conditioning of the packed capillaries for high efficiency separations without necessity for sodium dodecyl sulfate (SDS). Separation conditions for the nonporous materials were modified from those previously determined on porous reversed-phase silica. Feasibility for method development and validation of a parent pharmaceutical compound and related impurities in the range of 0.1-120% of a 5 mg/mL concentration was assessed and reported. An approach to improving detection sensitivity through use of large-bore capillaries is briefly discussed.

Topics: Anthracenes; Biphenyl Compounds; Chromatography, High Pressure Liquid; Electrophoresis, Capillary; Evaluation Studies as Topic; Feasibility Studies; Fluorenes; Magnetics; Naphthalenes; Pressure; Sensitivity and Specificity; Silicon Dioxide; Thiourea

Topics: Animals; Heavy Metal Poisoning; Metals, Heavy; Naphthalenes; Poisoning; Poisons; Rats; Strychnine; Thallium; Thiourea

Topics: Animals; Anti-Bacterial Agents; Dogs; Humans; Hydrocarbons, Aromatic; Naphthalenes; Poisoning; Thiourea