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1.
Manassis Mitrakas Roxanne Tzimou-tsitouridou Vissarion Keramidas 《International journal of environmental analytical chemistry》2013,93(3-4):343-351
Abstract The spectrophotometric method of bromate (BrO3 ?) determination by phenothiazines was applied to natural water samples and the interferences due to the presence of inorganic and humic substances were investigated. Common ions present in natural waters did not interfere and only the less abundant NO2 ? and Fe2+ exhibited strong interferences. Interferences of the two latter ions, if they existed, could be controlled and the method proved to be accurate and with a low detection limit. However, it was found that the presence of soluble humic substances resulted in positive interference, rendering the method unsuitable for bromate determination in natural waters and restricted its use in pure bromate solutions. This interference can be attributed to the electron acceptor groups invariably existing in the humic molecules. Since humic substances can remain in the water even after its ozonation, they will also contribute to a positive interference in bromate determination in potable waters. 相似文献
2.
O. Yu. Slabko N. V. Ageenko G. A. Verbitski V. A. Kaminski 《Chemistry of Heterocyclic Compounds》2002,38(2):226-230
Oxidative coupling of 4,9-diaza-1,2,4,9-tetrahydro-9H-fluorenes with o-aminophenol and o-aminothiophenol in the presence of MnO2 gives o-hydroxyphenyl- and o-mercaptophenylquinonediimines, cyclization of which gives derivatives of phenoxazine and phenothiazine. 相似文献
3.
The thermodynamic properties of 135 polychlorinated phenothiazines (PCPTZs) in the standard state are calculated using a combination of quantum mechanical computations performed with the Gaussian 03 program at the B3LYP/6-311G** level, and their octanol-water partition coefficients (logKow) are calculated based on group contributions. The chlorine substitution pattern strongly influenced the thermodynamic properties and hydrophilicity of the compounds. The thermodynamic properties of congeners also depend on the chlorine substitution pattern. The effect of chlorine substitution pattern is quantitatively studied by considering the number and position of Cl atom substitution (NPCS). The results show that the NPCS model may be used to predict the thermodynamic properties and hydrophilicity for all 135 PCPTZ congeners. 相似文献
4.
The structural determination by X-ray crystallography of the titled N-arylamine 4a, as well as AM1 calculations on a series of derivatives (4b–c, 5a–c), are reported. The compound 4a is monoclinic P21/c with a = 7.656(3), b = 23.655(5), c = 7.686(9) Å, = 112.59(6)°, V = 1285.2(2) Å3 and Z = 4. This structure has been used as a template for the building of some others derivatives used for AM1 calculations. The results show that the cyclization position on the aromatic rings, which can lead to two regioisomers, depends on the nature of the benzylic substituants. 相似文献
5.
6.
Mohamed H. Abdel-hay Magda H. Barary Ekram M. Hassan M. Abdel-Hady Elsayed 《光谱学快报》2013,46(8):1025-1044
Abstract Two photometric methods have been described for the assay of three phenothiazine drugs, isothipendyl hydrochloride, dimethothiazine mesylate &; trimeprazine tartarate in their tablets. The first is the differential tartarate in their tablets. The first is the differential spectro-photometric method &; based on the measurement of the absorbance (Δ A-), first derivative (Δ D1?) or second derivative (Δ D2?) values of the sulphoxide product of phenothiazine versus the intact. The second is based on the absorbance measurement of the pink coloured complex formed in a ratio of two drug moles t o one palladium ion. All these values are following Beer's law, which pernits the phenothiazines determination in their tablets with high accuracy. Using t-test &; F-test the results of different methods are of equal accuracy and reproducibility. Both methods complement each ot her during the routine analysis and quality control of the investigated phenothiazine drugs. 相似文献
7.
《Analytical letters》2012,45(16):2893-2911
Abstract Phenothiazines (PT) are an important family of compound from a medical point of view. They are widely used among the tricyclic antidepressants. Their application in therapy requires methods for their determination in pharmaceuticals and body fluids. The extractive-spectrophotometric methods are very useful for these determinations. They are based on the formation of the binary and ternary complexes. Phenothiazines react with some organic substances (e.g., picric acid, alizarin S, bromocresol green, and triphenylmethane dyes) as well as with thiocyanate or halide complexes of metals [e.g., Co(II), Pd(II), Fe(III), Cr(III), Au(III), Ti(IV), Pt(IV), Mo(V), W(V), U(VI)] forming well-defined ion-association compounds. The compounds are sparingly soluble in water but quantitatively extracted from the aqueous phase into organic solvents. The extracts are intensely colored and stable for a few days. These properties are the basis for utilizing the binary and ternary complexes of phenothiazines in chemical and pharmaceutical analysis. This review described the analytical application of these complexes. 相似文献
8.
Deep-lying π- and σ-orbitals of 10-alkylphenothiazines were studied by photoelectron spectroscopy and quantum-chemical AM1
calculations. It was demonstrated that in 10-ethylphenothiazine the lone electron pair of the S atom interacts with the π-system
of the aromatic fragments. The π-MOs, whose energies are a function of the dihedral angle between the planes of the benzene
rings of phenothiazines and are independent of the degree of pyramidality of the N atom, were found. The differences in the
energy of these MOs were used for estimating equilibrium dihedral angles of tricyclic molecules in the gaseous phase. These
values differ only slightly from those observed in the solid phase. The replacement of the hydrogen atom at position 10 by
the methyl group leads to a decrease in the dihedral angle, leaving the orientation of the substituent unchanged. The orbital
energies of phenothiazines, which were calculated by the AM1 method, adequately reflect the order of changes in the ionization
potential. However, contributions of the two highest occupied π-MOs to the total charges on the N and S atoms are inconsistent
with the experimental data.
For Part 10, see Ref. 1.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1542–1548, August, 1998. 相似文献
9.
An efficient cesium carbonate-mediated synthesis of phenothiazine derivatives from S-2-acetamidophenyl ethanethioates and ortho-dihaloarenes has been developed. This protocol affords an efficient approach for the construction of phenothiazine derivatives without the need of transition-metal catalyst or ligand. A plausible mechanism is proposed. 相似文献
10.
Naveen Gautam Neha Ajmera Shikha Gupta Priyadarshi Meena Ashok Kumar D. C. Gautam 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):2409-2417
This article describes the synthesis of 10H-phenothiazines from 2-aminobenzenethiol and o-halonitrobenzenes via Smiles rearrangement. Upon refluxing with hydrogen peroxide in glacial acetic acid, these phenothiazines yield the corresponding 10H-phenothiazine-5,5-dioxides. The phenothiazines have also been used as base to prepare ribofuranosides by the reaction with β-D-ribofuranose-1-acetate-2,3,5-tribenzoate. All the synthesized compounds have been characterized by spectral and elemental analysis and have been examined for antioxidant and antimicrobial activity. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献