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961.
N. T. Ul'chenko E. I. Gigienova U. A. Abdullaev K. L. Seitanidi A. U. Umarov 《Chemistry of Natural Compounds》1981,17(1):33-38
The composition of the seed oil ofCousinia severzovii has been studied; about 20 types and classes of compounds were isolated from the oil, including 6% of triterpenes with a molecular weight of 426 in the free state, as the acetylated derivatives, and as derivatives acylated with higher fatty acids of the 34:0–13:0 group in a ratio of 1:1:2, respectively; and 3.8% of oxidized acylglycerols (seven types). The classes of lipids were represented by no individual compound but only by a series of homologs or isomers.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 38–44, January–February, 1981. 相似文献
962.
Summary 1. The physical and chemical properties and the fatty-acid and glyceride compositions of the oils of four plants of the family Malvaceae have been studied. They all belong to the palmito-oleo-linoleic group.2. Their glyceride structure does not correspond to the principle of statistical distribution, since almost all the unsaturated-acid radicals are concentrated in the position.Order of the Red Banner of Labor Institute of the Chemistry of Plant Substances of the Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 252–255, May–June, 1971 相似文献
963.
A potassium electrode utilizing a solution of valinomycin in diphenylether and a porous membrane is compared with selectrodes in which the diphenylether has been replaced by a suitable plasticizer and the porous membrane support by a polymer net-work. The development of the polymer membrane allows the use of simplified selectrode construction with a “solid-state” calomel reference system; Rules for a successful choice of a suitable solvent-polymer combination are suggested and used for development of new Polyvinylchloride- and polyurethane-based membranes. 相似文献
964.
Reaction of dienamine 4a with substituted phenacyl bromides gave steroidal[3,4-b] furans 5a–g. The same principle reaction was utilized for the total synthesis of (±) 2 - (p - chlorophenyl) - 3 - oxa - A - nor - estra - 1,5(10), 9(11) - triene - 17 - acetate 12a. Treatment of 4a, b with benzenediazonium salts, in DMF, followed by a Fischer-indole cyclization yielded steroidal[6, 7-b] indoles 8a–k. Dienamine 4b could be annelated to benz[4, 5, 6] steroids 9a and 9b by reaction with methyl vinyl ketone and crotonaldehyde, respectively. 相似文献
965.
The luminescence of solid xenon at 20 K has been excited optically in the wavelength range 1550Åto 1150Å. The 1760Å emission band due to a transition of the molecule is found in agreement with α? or e?-excitation. The excitation spectrum yields a relatively high quantum efficiency of the Γ(3/2) exciton series indicating efficient self-trapping. The Γ(1/2) exciton series and conduction band states have a low quantum efficiency. 相似文献
966.
E. Ya. Misochko V. A. Benderskii A. U. Goldshleger A. V. Akimov A. V. Benderskii C. A. Wight 《Russian Chemical Bulletin》1997,46(4):678-686
The products of UV photolysis of ternary Ar?CH4(CD4)?F2 mixtures (1:c:c 0,c, c 0=0.001–0.01) at 13–16 K were identified by ESR and FTIR spectroscopy. These products are?CH3 (?CD3) radicals of typesI andII and molecular CH3F?HF complexes. The latter were characterized by the IR bands of the stretching C?F (1003 cm?1) and H?F (3774 cm?1) vibrations. The ESR spectra of radicalsI are asymmetric. The anisotropy of theg-factor (Δg~10?3) of radicalI indicates that the structure of the radicals is nonplanar. The ESR spectrum of the typeII radical is identical to that of matrix-isolated?CH3 (?CD3) radicals with the planar structure (Δg<5·10?5). Under the experimental conditions, the amount of complexes formed in the photolysis is equal to 0.022·c. When the photolysis is ceased, radicalI disappears after ≈103 s and radicalII is stabilized. The limiting concentrations of the stabilized?CH3 and?CD3 radicals are equal to 2·10?2·c and 2·10?3·c, respectively. A mechanism of the formation of the products is suggested. It is based on the assumption that both matrix-isolated CH4 and F2 and their heterodimers CH4?F2 are present in the samples and it takes into account the long-range migration of translationally excited flourine atoms. The CH3F?HF complexes and radicalsI are generated by the photolysis of the CH4?F2 heterodimers. The decay of radicalsI is caused by geminate recombination of proximate F...CH3 pairs. RadicalsII are formed in the reaction of translationally excited fluorine atoms with isolated CH4 (CD4) molecules. 相似文献
967.
E. Ya. Misochko V. A. Benderskii A. U. Goldshleger A. V. Akimov A. V. Benderskii C. A. Wight 《Russian Chemical Bulletin》1997,46(4):687-692
The products of reactions of dopant CH4 molecules with F atoms diffusing in solid argon at 20–30 K were identified by ESR and FTIR spectroscopy. The F atoms stabilized in the matrix were generated by UV photolysis of Ar?CH4(CD4)?F (1000∶1∶1) samples at 13 K. Subsequent heating above 20 K results in thawing off diffusion of the F atoms and formation of products of their reaction with CH4: radical-molecular complexes·CH3?HF (·CD3?DF) and radicals·CH3 (·CD3). The ESR spectra of the radicala are similar to those observed for matrix-isolated·CH3. The·CH3?HF complexes are characterized by the IR band of HF stetching vibration at 3764 cm?1. Two additional splittings on the H (a H·=2 G) and F(a F=16G) nuclei of the HF molecule appeal in the ESR spectrum of the complex. The latter splitting is retained in the·CD3?DF complex, whereA D· <0.3G The rate constant of the reaction CH4+F→·CH3+HF is equal to ?10?25 cm3s?1 at 20 K. Its activation energy (1.7±0.2 kcal mol?1) is ?0.5 kcal mol?1 greater than that in the gas phase. The collinear C3v-configuration of the·CH3?HF complex, which is similar to the configuration of the reagents in the transition state of the reaction considered, was established by the comparison of the exprrimental constants of hyperfine coupling with the results of the quantum-chemical calculation. 相似文献
968.
The interfacial tension of hybrids composed of a tin-based phosphate glass (Pglass) and thermoplastic polymers, low-density polyethylene (LDPE), polystyrene (PS), and polypropylene (PP) was investigated using pendant drop and droplet deformation methods. High surface tension values were determined for the pure Pglass and subsequently used to obtain interfacial tension values that were found to be greater than that of most polymer blends reported in the literature. Small amplitude oscillatory shear data were fitted to the Choi-Schowalter and Palierne emulsion models in order to estimate the interfacial tension and to validate the accuracy (or lack thereof) of using a polymer emulsion model on the special Pglass-polymer systems. Although some of the hybrids showed satisfactory agreement with the emulsion models, wide ranges of interfacial tensions were obtained, suggesting that a more complicated theory that explicitly takes the Pglass-polymer interactions, shape factor, and size distributions of the dispersed Pglass phase into account may be necessary for more accurate modeling of these special hybrid systems with enhanced benefits. 相似文献
969.
W Haasnoot R Schilt A R Hamers F A Huf A Farjam R W Frei U A Brinkman 《Journal of chromatography. A》1989,489(1):157-171
An immunoaffinity precolumn (immuno precolumn) packed with Sepharose-immobilized polyclonal antibodies against the anabolic hormone 17 beta-19-nortestosterone (beta-19-NT) was used for the selective on-line pretreatment of raw extracts of urine, bile and tissue samples by high-performance liquid chromatography. Using UV detection (247 nm), beta-19-NT and its metabolite 17 alpha-19-nortestosterone (alpha-19-NT) can be determined in biological samples with a detection limit of 0.05 microgram/kg. Owing to the high clean-up efficiency of the immuno precolumn and the large sample volumes used, confirmation by gas chromatography-mass spectrometry is possible at this level. In urine samples from a calf treated with 19-nortestosterone 17 beta-laurate, the maximum concentrations of beta-19-NT (1.3 micrograms/l) and alpha-19-NT (3.1 micrograms/l) were found seven days after intramuscular administration. In a bile sample from this calf only alpha-19-NT (55 microgram/l) was detected. In meat samples from three treated calves, the concentration of beta-19-NT varied from 0.1 to 1.6 micrograms/kg and no alpha-19-NT could be detected. In liver samples from these calves, the concentrations of beta-19-NT and alpha-19-NT were less than 0.05-0.1 and 0.5-0.9 micrograms/kg, respectively. In the corresponding kidney samples, the concentrations of beta-19-NT and alpha-19-NT were 0.4-0.5 and 0.5-1.6 micrograms/kg, respectively. The application of the same immuno precolumn to the determination of 17 beta- and 17 alpha-trenbolone, two structurally related steroids, is also demonstrated. 相似文献
970.
The seeds of Stapelia gigantea are very rich in ester glycosides (ca. 5,9%). Mild acid hydrolysis gave a mixture of sugars which, after paper chromatography and electrophoresis, was found to be probably composed of cymarose, oleandrose, digitoxose, arabino-2,6-dideoxyhexose (= canarose) and pachybiose. The mixture of the raw genins gave after alkaline hydrolysis a mixture of about nine deacyl genins (C, D, E, F1, F2, F3, G, H, J); the acids split off during hydrolysis were not identified. The nine deacyl genins are probably closely related pregnane derivatives. The main component (E), C21H30O4, was obtained in crystalline state, and was named stapelogenin. Its probable structure is reported in the following publication. 相似文献