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991.
Conclusions Polychlorinated hydrocarbons containing the CCl3 group can be used as telogens in the telomerization of olefins in the presence of iron pentacarbonyl and i-C3H7OH. The formation of the telomer homologs in high yield obeys the general rules that were established for the given initiating system.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2837–2839, December, 1971.  相似文献   
992.
The extent of energetic stabilization by alkyl groups with -electron systems via hyperconjugation is investigated theoretically by MINDO molecular orbital calculations. In neutral hydrocarbons, this stabilization represents about 4 % of the effective C-C bond energy, and is additive in the number of alkyl groups present. Calculations for conjugated, polar, and ionic molecules are also discussed.
Zusammenfassung Das Ausma\ der energetischen Stabilisierung von -Elektronen-Systemen mit Alkylgruppen durch Hyperkonjugation wird theoretisch durch MINDO-MO-Berechnungen untersucht. In neutralen Kohlenwasserstoffen betrÄgt diese Stabilisierung etwa 4% der effektiven C-C Bindungsenergie und ist additiv entsprechend der Zahl der vorhandenen Alkylgruppen. Berechnungen für konjugierte, polare und ionische Moleküle werden ebenfalls diskutiert.

Résumé La méthode des orbitales moléculaires MINDO est utilisée pour calculer le degré de stabilisation par hyperconjugaison entre des groupements alkyles et des systèmes d'électrons . Dans des hydrocarbures neutres cette stabilisation représente environ 4% de l'énergie effective de la liason C-C; elle est additive par rapport au nombre de groupements alkyles. On discute aussi des calculs effectués pour des molécules conjuguées polaires ou ioniques.
  相似文献   
993.
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   
994.
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   
995.
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   
996.
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   
997.
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   
998.
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   
999.
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   
1000.
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   
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