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991.
When heated with carbon disulfide in pyridine 2-hydrazinonaphth[1, 2-d]imidazole yields S-triazolo[4, 3-b]-naphth[1, 2-d]imidazole-3-thione. Kinetic and not steric factors determine the formation of this compound. Its trans-angular structure is demonstrated by the agreement between its UV spectrum and that of 11-methyl-S-triazolo[4, 3-b]naphth[1, 2-d]imidazole-3-thione, prepared from 1-methyl-2-hydrazinonaphth[1, 2-d]imidazole and carbon disulfide, as well as by the identity of their methylation products. Methyl iodide methylation, in the presence of sodium methoxide, of S-triazolo[4, 3-b]naphth[1, 2-d]imidazole-3-thione, like that of S-triazolo[4, 3-a]benzimidazole-3-thione, takes place stepwise. First the methyl group adds to the nitrogen atom of the imidazole ring, and only then to the thiol group of the triazole ring.For Part VII see [3].  相似文献   
992.
There has been synthesized a series of 1,4-dihydropyridines having an N-alkylpyridinium substituent at position 4 with a varying length of hydrocarbon chain. Their affinity to model (liposomal) membranes has been studied. It was found that this affinity increased with lengthening of the hydrocarbon chain on the Npyridinium substituent at the 4-position of the 1,4-dihydropyridine ring. However, lengthening of the hydrocarbon chain in the 3,5-ester groups of the 1, 4-dihydropyridine ring led to a decrease in the binding to the liposome when a 4-(N-hexadecylpyridinium) substituent was present.Latvian Institute of Organic Synthesis, Riga LV-1006. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1112–1117, August, 1995. Original article submitted June 6, 1995.  相似文献   
993.
The use of topological indices to reveal the relationship between molecular structure and mesomorphous properties is discussed. Mathematical models for classification of mesophase types are proposed. The effect of molecular structure and attractive ability on phase transition temperatures is described. Examples of using correlation equations to predict the properties of 2,5-disubstituted 1,3-dioxanes are given. A. V. Bogatskii Physicochemical Institute, Ukrainian Academy of Sciences. Translated fromZhurnal Struktumoi Khimii, Vol. 35, No. 4, pp. 53–60, July–August, 1994. Translated by L. Smolina  相似文献   
994.
3-Ethoxycarbonylquinuclidine obtained by the Grob method is a mixture of 3-ethoxycarbonyl-1-azabicylo-[2.2.2]- and, according to 13C NMR data, 5-ethoxycarbonyl-5-azatricyclo[3.2.1.02,7]octanes (1621). 3-Ethoxy-carbonylquinuclidine was purified by recrystallization of the hydrochloride, hydrolyzed by water to 3-quinuclidinecarboxylic acid, and reduced by LiAlH4 to 3-quinuclidinylmethanol.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, 1509–1512, November, 1992.  相似文献   
995.
Condensation of bis-(2-chloroethyl)phosphoramidic dichloride with 3′-amino-3′-deoxy-N,N-dimethyladenosine afforded the 2′,3′-cyclicphosphorodiamidate (III). By an improved synthesis, methyl 3-amino-3-deoxy-β-D-ribofuranoside was obtained as a model compound for conversion to the analogous 2,3-cyclicphosphorodiamidate (XII). Existence of the latter as two diastereomers due to phosphorus asymmetry was shown by nmr analysis, using comparison with the 5-(O-p-nitrobenzoate) (XIII) as a basis for assignments.  相似文献   
996.
Sol-gel process of hydrolytic polycondensation of tetramethoxysilane with trimethoxysilyl derivatives of lanthanide phosphoramide complexes was studied in order to obtain photoluminescent organic-inorganic hybrid materials. Original Russian Text N.N. Khimich, Yu.L. Zub, L.A. Koptelova, T.S. Mashchenko, E.P. Troshina, M.G. Voronkov, 2006, published in Zhurnal Prikladnoi Khimii, 2006, Vol. 79, No. 11, pp. 1789–1794.  相似文献   
997.
Reactions of 4-fluoro-5-polyfluoroalkyl-1,2-dithiol-3-thiones with hydroxylamine and hydrazines occur with replacement of the thiocarbonyl by imino group affording oximes and hydrazones respectively. N-Alkyl-and N-aryl-3-imino-1,2-dithiolenes formed in reactions of 3-chlorothio-1,2-dithiolium salts with primary alkyl-or arylamines. 3-Chlorothio-1,2-dithiolium salts react with compounds possessing an active methylene group yielding 3-ylideno derivatives of 1,2-dithiolenes.  相似文献   
998.
Reaction of derivatives of 1-methyl-2,2-dichlorocyclopropanecarboxylic acid with three- and four-coordinate phosphorus acids was studied. It was established that the nucleophilic substitution on the carbonyl carbon atom proceeds without cleavage of the three-membered ring and leads to new types of phosphorus-containing cyclopropanes. The products were found to enhance the germination energy and laboratory germination of cereal, legume, and vegetable seeds.  相似文献   
999.
Silicon carbonitride films were synthesized from new volatile precursors by plasma-enhanced chemical vapor deposition. Based on a detailed study of the morphology of film surfaces, it was found that the layer material was an amorphous matrix with inclusions of nanosized crystals. Calculation of the structure of the crystalline phase from synchrotron X-ray diffraction patterns demonstrated that the entire set of the diffraction peaks detected is indexed by a tetragonal structure with the lattice parameters a = 9.6 Å and c = 6.4 Å. This is consistent with the fact that the carbon 1s and nitrogen 1s core level X-ray photoelectron spectra exhibited only sp 3 bonding, which was expected for superhard carbon nitride phases.  相似文献   
1000.
The composition and content of polysaccharides obtained from different samples of rice husk by successive treatment with water, ammonium oxalate (or oxalic acid), and alkali were studied. The chemical composition of the rice husk residues after the extraction was examined, and the possibility of their use for preparing amorphous silica or cellulose-containing products, depending on the hydrolysis conditions, was assessed.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 11, 2004, pp. 1901–1904.Original Russian Text Copyright © 2004 by Zemnukhova, Tomshich, Mamontova, Komandrova, Fedorishcheva, Sergienko.  相似文献   
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