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931.
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
932.
933.
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
934.
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
935.
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
936.
M. A. Allakhverdiev A. Z. Khalilova V. M. Farzaliev Yu. M. Sultanov 《Chemistry of Heterocyclic Compounds》1988,24(5):485-488
The reaction of phenyl- and p-tolylmagnesium bromides, as well as di, tri, and tetramethylbenzene, with epichlorohydrin was used to synthesize the corresponding chlorohydrins, which were then converted to various benzyl-substituted oxiranes and thiiranes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 598–602, May, 1988. 相似文献
937.
Sensitive derivative polarographic adsorption waves have been observed for alkaline-earth metal-TP complexes in 0.15M potassium hydroxide containing 3 x 10(-5)M thymolphthalexone (TP). The limit of detection for calcium, strontium and barium was 7.5 x 10(-7)M and for magnesium 4.0 x 10(-6)M. The proposed method has been used successfully for determining trace amounts of calcium in natural waters and hair samples. The composition of the complex has been shown to be 1:1 alkaline-earth metal:TP and various experiments have confirmed that the wave is an adsorption wave. The reaction mechanism has been studied by a number of methods. 相似文献
938.
Z. Gyrgydek K. E. Kvr I. Miskolczi A. Zkny F. Rantal R Luger M. Katona Strumpel 《Journal of heterocyclic chemistry》1996,33(4):1099-1105
The reaction of (4S)-5,5-dimethyl-4-thiazolidine-carboxylic acid 1 with alkyl and aryl isothiocyanates 2 gave bicyclic thiohydantoins 3 . The (2R,4S)- and (2S,4S)-mixtures of 2-substituted 5,5-dimethyl-4-thiazolidine-carboxylic acids 4 and 8 containing two centers of chirality in the analogous reaction afforded thiohydantoins 7 and 10 , respectively, with (1R)-configuration. In some cases we managed to isolate the thioureido acid intermediates 6 and 9 or their triethylamine salts which afforded the corresponding bicycles 7 and 10 under thermal cyclization or acidification. The stereochemistry has been elucidated by high resolution ram studies, optical rotation measurements and X-ray crystallography. 相似文献
939.
Oxidation of the corresponding 3, 6-diacetylcarbazoles gives 9-n-butyl- and 9-isoamylcarbazole-3, 6-dicarboxylic acids. 9-Alkylcarbazole-3, 6-dicarboxylic acids are converted to acid chlorides, which are esterified with allyl alcohol without being isolated pure. Allyl 9-ethyl-, 9-n-butyl- and 9-isoamylcarbazole-3, 6-dicarboxylates are synthesized. The ability of these esters to polymerize and to undergo copolymerization with methyl mercaptan is demonstrated with the example of diallyl 9-ethylcarbazole-3, 6-dicarboxylate.For Part XII see [8]. 相似文献
940.
Z. Hölgye 《Journal of Radioanalytical and Nuclear Chemistry》1994,187(6):451-457
A procedure for separation of plutonium from some biological and environmental materials has been tested in model and real conditions. The procedure involves a commonly used way of conversion of plutonium to oxidation state (IV) in nitric acid medium and sorption of Pu(IV) on a strongly basic anion exchanger from hydrochloric acid medium thus eliminating interference of228Th with the238Pu analysis. 相似文献