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981.
982.
M. A. Yurovskaya A. Z. Afanas'ev S. L. Druzina Yu. G. Bundel' 《Chemistry of Heterocyclic Compounds》1989,25(6):667-672
The introduction of bulky alkyl substituents (iso-Pr,tert-Bu) into any positions of the starting 3-nitropyridinium salt only increases the reaction time and decreases the yields of the corresponding alkylindoles somewhat.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 805–810, June, 1989. 相似文献
983.
984.
Z. Varga G. Surányi N. Vajda Z. Stefánka 《Journal of Radioanalytical and Nuclear Chemistry》2007,274(1):87-94
A rapid and simple sample preparation method for plutonium determination in environmental samples by inductively coupled plasma
sector field mass spectrometry (ICP-SFMS) and alpha-spectrometry is described. The developed procedure involves a selective
CaF2 co-precipitation for preconcentration followed by extraction chromatographic separation. The proposed method effectively
eliminates the possible interferences in mass spectrometric analysis and also removes interfering radionuclides that may disturb
alpha-spectrometric measurement. For 239Pu, 240Pu and 241Pu limits of detection of 9.0 fg·g−1 (0.021 mBq), 1.7 fg·g−1 (0.014 mBq) and 3.1 fg·g−1 (11.9 mBq) were achieved by ICP-SFMS, respectively, and 0.02 mBq by alpha-spectrometry. Results of certified reference materials
agreed well with the recommended values. 相似文献
985.
V. I. Terenin E. A. Sumtsova S. Z. Vatsadze E. V. Kabanova I. F. Leshcheva A. P. Pleshkova N. V. Zyk 《Chemistry of Heterocyclic Compounds》2003,39(7):943-952
We have studied the behavior of asymmetrically substituted dipyrrolo[1,2-a;2',1'-c]pyrazines and their 5,6-dihydro analogs under phosphorylation reaction conditions. 相似文献
986.
José Elguero Alain Fruchier El Mostafa Tjiou Sviatoslav Trofimenko 《Chemistry of Heterocyclic Compounds》1995,31(9):1006-1026
The carbon-13 chemical shifts and some selected coupling constants of 183 indazoles are reported. The main conclusions of the original references are briefly summarized.Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1159–1179, September, 1995. 相似文献
987.
988.
Enantiomers and diastereomers of chrysanthemic, permethrinic, and deltamethrinic pyrethroic acids were separated from each other, using positively ionizable permethyl monoamino beta-cyclodextrin (PMMAbetaCD). The highest chiral resolution value was 20.0. The optimum conditions of separation were found to be 16 mM PMMAbetaCD concentration and pH 6.5, where analytes and selector were in oppositely ionized states. Selectivity of PMMAbetaCD proved to be the best among the cyclodextrin derivatives studied. 相似文献
989.
M. Kh. Dzhukharova B. Tashkhodzhaev Z. Saatov N. D. Abdullaev 《Chemistry of Natural Compounds》1994,29(4):484-489
A new ecdysteroid with the composition C27H44O6 which has been called brahuisterone has been isolated from the epigeal part of the plantSilene brahuica Boiss. Its chemical and complete spatial structures have been established by spectral studies and the x-ray structural method (diffractometer, Cu-K radiations, 996 reflections, direct method, R=0.119).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbekistan Republic, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 553–558, July–August, 1993. 相似文献
990.
B. A. Arbuzov Z. G. Isaeva M. G. Belyaeva V. V. Ratner O. N. Kataeva I. A. Litvinov V. A. Naumov 《Russian Chemical Bulletin》1992,41(1):117-119
Oxidation of 2-carene by lead tetraacetate in acetic acid afforded p-menth-1(10),2-dien-7-ol, 2-acetyl-6,6-dimethylbicyclo[3.1.0]hexane, p-menth-2-ene-1,7-diol, p-menth-1-ene-3,7-diol, and 2-(m-tolyl)propanol-2.Deceased.A. M. Butlerov Scientific Research Chemical Institute, V. I. Ul'yanov-Lenin Kazan' State University, 420008 Kazan. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 147–150, January, 1992. 相似文献