Novel spiro[fluorene-9,4′-(1′,2′,3′,4′-tetrahydropyridine)]-5′-carbonitriles 6a-c have been obtained from the reaction of N1,N2-diarylacetamidines 1a-c with (2,4,7-trinitro-9H-fluoren-9-ylidene)propanedinitrile ( 2 ) in ethyl acetate solutions at ambient temperature for 6a,b or under reflux for 6c , respectively. 相似文献
A new simple and sensitive spectrophotometric procedure for the determination of sulfacetamide sodium (I), sulfadiazine (II), sulfadimidine (III) and sulfathiazole (IV) is based on the reaction of the drug with acetylacetone-formaldehyde reagent to give a yellow product having max at 400 nm. Optimization of the reaction conditions has been investigated. A linear correlation was obtained between absorbance at max and the concentration. The Beer's law limits of I, II, III and IV are 4–80, 4–72, 4–60 and 4–80 g/ml, respectively. For more accurate results, Ringbom optimum concentration ranges were evaluated to be 6–76, 8–66, 6–56 and 8–75 g/ml for I, II, III and IV, respectively. The molar absorptivities and Sandell sensitivities for all sulfa drugs under consideration were evaluated. Relative standard deviations of 0.98, 1.07, 0.86 and 0.79% were obtained for I, II, III and IV, respectively. The method has been compared to the official method and found to be simple, accurate (t-test) and reproducible (F-test). The developed procedures were applied for bulk sulfa drugs and some of their dosage forms without interferences from additive and common prescribed drugs. 相似文献
The method of perturbed angular distributions was used to measure the temperature dependence of the electric field gradient in Er single crystal for 98 KT156 K. The I=11– isomer in Er154) was used as a probe. 0 increases monotonically for 98 KT259 K and then decreases. A possible cause for this effect may be short range interactions between the f electrons above the Neel point.Visitor from the Weizmann Institute, Rehovoth, Israel. 相似文献
New substituted 3-amino-5,7,8-trihalo-6-hydroxycinnoline-4-carbonitriles 7 and 8 and the 3-amino-5-chloro-6-hydroxy-benzo[h]cinnoline-4-carbonitrile 9 were synthesized in two-steps starting from tetrahalo-1,4-benzoquinones or dichloro-1,4-naphthoquinones, malononitrile and hydrazine. 相似文献
5‐(2‐Aminothiazol‐4‐yl)‐8‐hydroxyquinoline 2 has been synthesized by treating thiourea with 5‐chloroacetyl‐8‐hydroxyquinoline 1 . The amine 2 was treated with aromatic aldehydes to furnish schiff bases 6a‐c which on treatment with phenyl isothiocyanate gave the corresponding thiazolo‐s‐triazines 7a‐c . Reaction of 2 with phenyl isothiocyanate gave the corresponding aminocarbothiamide derivative 8 which on reaction with malonic acid in acetyl chloride afforded thiobarbituric acid derivative 9 . Coupling of 9 with diazonium salt gave the phenyl hydrazono derivative 10 . However, reaction of 2 with carbon disulphide and methyl iodide afforded dithiocarbamidate 12 which on treatment with ethylenediamine, o‐aminophenol and/or phenylenediamine gave the aminoazolo derivatives 13–15 , respectively. Other substituted fused thiazolopyrimidines 16–20 have been also prepared by the reaction of 2 with some selected dicarbonyl reagents. The characterisation of synthesized compounds has been done on the basis of elemental analysis, IR, 1H‐NMR and mass spectral data. All the newly synthesized compounds have been screened for their antimicrobial activities. 相似文献
The structure of polymers obtained by polymerization of methoxyallene and ethoxyallene with transition-metal catalysts depends on the catalyst employed. Rapid polymerization at 0°C through the unsubstituted double bond occurred with π-allylnickel halides, NiCl2/AlEt3 and CoCl2/AlEt3, yielding polymers with the structure Typical Ziegler–Natta catalysts (TiCl4, VOCl3 or FeCl3 with AIEt3) gave polymers mainly with the structure although some of the structural units were probably present as well. Polymers having conjugated double bonds were prepared with PdCl2, [(π-allyl)PdCl]2, and PdCl2(C6H5CN)2 as catalysts. Palladium iodide produced polymers with all three of the above structural units present. Polymerization occurred more slowly with these palladium catalysts. A preliminary examination of the effect of variation of solvent, ligand, co-catalyst, and temperature on the rate and structure of the polymers obtained with the palladium catalysts is reported. 相似文献
Here, iron, sulfur and poly(ethylene glycol) doping to TiO2 nanoparticles toward the effect on photodegradation of the methylene blue (MB) and Evans blue (EB) was investigated. The present nanostructured photocatalysts displayed notable catalytic activity for the decomposition of colorants in water under visible light irradiation. The photocatalytic reaction constants of different samples were determined for EB and MB to be 0.007, 0.008, 0.009 and 0.01, 0.026, 0.021 1/min, respectively. The values of optical band gap for pure TiO2, Fe–S/TiO2, and Fe–S/TiO2@PEG were estimated to be 3.21, 2.75, and 2.81, respectively. X-ray analysis was performed and correlated with BET, Fe–SEM, and TEM results. The lattice structure was studied by W–H (Williamson–Hall) and H–W (Halder–Wagner) methods with a different assumption in the isotropic and homogenous nature. The results revealed that the SSP model shows the most accuracy and adaption to determine the lattice structure.
Three regularities have been introduced for liquids (T < TC and ρ > ρC) based on average potential energy. The experimental data have been used to show the validity of the regularities. First, there exists near-linearity relation between and ρ for all isotherms of a liquid, where Pi and ρ are internal pressure and density, respectively. Second, changes linearly with ρ for each isotherm of any liquid, where Z and Vm are compressibility factor and molar volume, respectively. Third, a new regularity using the definition of bulk modulus and our new equation of state between reduced bulk modulus and density has been introduced, that is versus ρ must be linear for all isotherms of a liquid where Br is the reduced bulk modulus.
A new equation of state has been also derived. The density of some liquids in the extensive ranges of temperature and pressure has been calculated using the new equation of state. The densities calculated from this equation agree with experiment to better than 0.3%. The new equation of state can predict internal pressure, thermal expansion coefficient, and isothermal compressibility of liquids within experimental error. 相似文献
For a Noetherian local domain R let R+ be the absolute integral closure of R and let R∞ be the perfect closure of R, when R has prime characteristic. In this paper we investigate the projective dimension of residue rings of certain ideals of R+ and R∞. In particular, we show that any prime ideal of R∞ has a bounded free resolution of countably generated free R∞-modules. Also, we show that the analogue of this result is true for the maximal ideals of R+, when R has residue prime characteristic. We compute global dimensions of R+ and R∞ in some cases. Some applications of these results are given. 相似文献
A simple and efficient catalytic oxidation of urazoles and a bis-urazole to the corresponding triazolinediones by treatment
with Al(NO3)3.9H2O in the presence of a catalytic amount of silica sulfuric acid is described. A good range of urazole derivatives was selectively
oxidized in CH2Cl2 at room temperature in good to excellent yields. 相似文献