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871.
S. A. Shevelev V. M. Vinogradov I. L. Dalinger T. I. Cherkasova 《Russian Chemical Bulletin》1993,42(11):1857-1861
A method for the synthesis of bi-, ter-, and quaterpyrazoles by cyclization ofC-(diformylmethyl)nitropyrazoles with hydrazine has been elaborated. Some of theirC- andN-derivatives have been obtained. The compounds prepared have been characterized by1H,13C,14N, and15N NMR spectra.For communication 6, see Ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1941–1945, November, 1993. 相似文献
872.
Desialylated fetuin (asialofetuin) was adopted as a carrier for introducing drugs in parenchymal liver cells. Mitomycin C, as a model guest-compound, was covalently attached to asialofetuin through a spacer of the succinyl group. The asialofetuin-mitomycin C conjugate contained 4.4 w/w% of mitomycin C and liberated it gradually at physiological conditions (t1/2 = 37 h). The survival time of the conjugate in rat blood circulation was significantly smaller than that of the non-desialylated fetuin conjugate; the elimination half-life was 7.3 min after intravenous injection. At 30 min after injection of the conjugate in rats, 40% of the dose was present in the liver. Parenchymal cells in the liver selectively took up the conjugate, which was highly distributed to the lysosomal fraction in the cell. The greater uptake of the conjugate by hepatocytes reflected the increased excretion in the bile; totally 10.4% of the dose was recovered. 相似文献
873.
Polenova TV Borzenko AG Marutsenko IV Revelsky IA 《Journal of chromatographic science》2001,39(7):293-296
The monitoring of the physiological and functional state of personnel from dangerous industries is very important for the ensuring of ecological security. Usually, this involves testing for the consumption of alcohol and drugs of abuse. During the last several years the use of legal psychotropic drugs has increased and the control over these drugs has became an actual problem. As is well known, the long-term history of drugs present in the body is accessible through hair analysis. This is why the aim of our research is to create a screening procedure based on coupling high-performance thin-layer chromatography with microliquid extraction as a psychotropic drug testing method for hair. Some widely distributed antidepressants, neuroleptics, and sedative drugs are chosen for research. The optimal experimental conditions for all of the consequent steps for the screening detection of the model samples are determined. The visual and densitometric detection limits allow for the employment of the proposed technique for a fast and cost-effective analysis of the drugs of abuse. 相似文献
874.
M. O. Manukyan A. V. Babakhanyan G. A. Panosyan A. Kh. Gyul’nazaryan S. T. Kocharyan 《Russian Journal of General Chemistry》2007,77(8):1370-1372
Ammonium salts containing phenacyl group in combination with 4-allyloxy(phehoxy)-2-butynyl group, when treated with a suspension of potassium hydroxide in benzene, undergo the 3,2-Stevens rearrangement with the formation of allenic amino ketones which under the reaction conditions give the furan derivatives. 相似文献
875.
Progressive reaction networks as frequently arise in chemistry are naturally identifiable as "partially ordered sets" (or posets). Here the direction of the reaction identifies the partial ordering of the set of molecular species. The possibility that different properties are similarly ordered is a further natural consideration and is here investigated for a suite of over 30 properties for (methyl and chloro) substituted benzenes. Such a posetic correlation is favorably demonstrated for these substituted benzenes, and it is illustrated how suitable properties may be simply predicted in an interpolative parameter-free (albeit not model-free) fashion through the use of the reaction poset. Some numerical model-quality indicators are identified, and the simple approach is deemed quite reasonable. 相似文献
876.
New polymethine dyes with an indolo[3,2-d]thiazole residue are described, and their spectral properties are discussed. Replacement of the vinylene group in the naphtho[1,2-d]thiazole residue by an NH group leads to a considerably greater bathochromic shift of the absorption maximum of carbo- and merocyanines as compared with replacement by a sulfur atom. The basicity of the indolo[3,2-d]thiazole residue is higher than the basicity of the naphtho[1,2-d]-thiazole and thionaphtheno[3,2-d]thiazole residues.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1606–1610, December, 1972. 相似文献
877.
Abstract— Near-ultraviolet (near-UV; 320–405 nm) irradiation of Escherichia coli B/r induces the formation in vivo of 4Srd-Cyd adducts in transfer RNA, as evidenced by (1) fluorescence spectrum changes of tRNA extracted from irradiated cells and reduced with NaBH4, (2) thin-layer chromatography on cellulose of hydrolysates of trichloroacetic acid-precipitable extracts of irradiated cells, and (3) comparison of these findings with adduct formation induced by near-UV irradiation of purified mixed tRNA from E. coli. The kinetics of induction of the 4Srd-Cyd adduct in vivo, and the near-UV fluences required, provide strong support for our earlier hypothesis that formation of these adducts is responsible for near-UV-induced growth delay in E. coli. 相似文献
878.
A nondestructive photon activation procedure with 30 MeV bremsstrahlung followed by high-resolution gamma-spectrometry has
been applied to the multielement determination in tobacco leaves and commercial cigarettes. The elements determined by this
method included essential minor elements such as Ca, Cl, K and Mg, essential trace elements such as Fe, Mn and Zn, and possibly
toxic elements such As and Sb. The NBS Orchard Leaves could successfully be used as a comparative standard. The method is
quite simple and gives good reproducible results for at least 12 elements. 相似文献
879.
A non-empirical molecular orbital method, particularly suitable for calculations on cage-like molecules, is described. The method uses as basis functions the set of free-electron functions which are the solutions of Schrödinger's equation for an electron confined between two concentric, spherical potential energy barriers. Application of the theory to the SCF calculation of the energies of the delocalized electrons in benzene and tetrasulphur tetranitride shows that the model is capable of interpreting the properties of such systems. However, it does highlight a difficulty in the calculation of excited state energies with one-centre models which appears to be largely unrecognized.Extension of the method to a consideration of all the valence electrons, using P4 as an example, reveals problems the origin of which is an inadequate treatment of the core electrons. It is suggested that these problems may best be dealt with by use of a suitable pseudo potential. 相似文献
880.
Relativistic symmetry orbitals are given for the double group D3h. For atomic orbitals at the symmetry center a general expression is presented. The atomic orbitals of the s, p½, and p3/2 variety outside the center are also considered. The representation matrices are given in explicit form. 相似文献