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Spirodienones bearing the 1-azaspiro[4.5]decane ring system have been synthesized from N-methoxy-(4-halogenophenyl)amides by the intramolecular ipso attack of a nitrenium ion generated with [hydroxy(tosyloxy)iodo]benzene in trifluoroethanol. 相似文献
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Riki Seki Etsuko Kimura Toshiyuki Takahashi Nagao Ikeda 《Journal of Radioanalytical and Nuclear Chemistry》1990,138(1):17-31
The concentration of129I in soil in Japan was determined by neutron activation analysis. For the activation analysis, pre-irradiation chemical separation of the iodine was carried out by acid decomposition and distillation and post-irradiation treatment was performed by ion exchange and solvent extraction. The concentration of stable iodine and137Cs were also determined and compared with the behavior of129I in soil.Soil samples from Ibaraki, Fukui, Fukushima, and Nagasaki Prefectures were analyzed and129I was detected in amounts ranging from 10–7 to 10–5 Bq/g soil in uncultivated surface soil. There are apparently small variations in the129I concentrations in each of the regions analyzed.From depth profile studies in sandy soil, the iodide form of129I was found to migrate downward at a relatively rapid rate while other species remain longer in the surface soil. 相似文献
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In an effort to develop an efficient synthetic method of highly diastereoselective (2′R)- and (2′S)-2′-deoxy[2′-2H]guanosines, chemoenzymatic conversion was investigated. The synthesis of (2′R > 98% de)-2′-deoxy[2′-2H]guanosine was achieved by biological transdeoxyribosylation using (2′R > 98% de)-2′-deoxy[2′-2H]uridine, 2,6-diaminopurine, and Enterobacter aerogenes AJ-11125, followed by treatment with adenosine deaminase. (2′S > 98% de)-2′-Deoxy[2′-2H]guanosine was synthesized from (2′S > 98% de)-2′-deoxy[2′-2H]uridine and 2,6-diaminopurine using thymidine phosphorylase and purine nucleoside phosphorylase instead of E. aerogenes AJ-11125. 相似文献
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The present efficient synthesis of [5'-13C]ribonucleosides and 2'-deoxy[5'-13C]ribonucleosides is characterized by the synthesis of the D-[5-13C]ribose derivative as an intermediate via the Wittig reaction of 4-aldehydo-D-erythrose dialkyl acetals with Ph3P13CH3I-BuLi to introduce the 13C label at the 5-position of a pentose. This was followed by the highly diastereoselective osmium dihydroxylation for the preparation of 2,3-di-O-benzyl-D-[5-13C]ribose dialkyl acetal and the cyclization from D-[5-13C]ribose dialkyl acetal derivatives to the alkyl D-[5-13C]ribofuranoside derivative by the use of LiBF(4). The obtained D-[5-13C]ribose derivative was converted into [5'-13C]ribonucleosides and subsequently into the corresponding 2'-deoxynucleosides. 相似文献
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T. Tanaka A. Hazato K. Bannai N. Okamura S. Sugiura K. Manabe S. Kurozumi M. Suzuki R. Noyori 《Tetrahedron letters》1984,25(43):4947-4950
6-Oxoprostaglandin E1 methyl ester was synthesized in a single pot from ()-4--butyldimethylsiloxy-2-cyclopentenone by organocopper conjugate addition with an ω side-chain unit, trapping of the resulting enolate with 6-methoxycarbonyl-2-nitrohex-1-ene, and treatment with aqueous titanium(III) trichloride. Hydrolysis of the methyl ester was accomplished by porcine liver esterase. 6-Oxoprostaglandin F1α, was obtained from 6-nitroprostaglandin E1 methyl ester in four steps. 相似文献
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Tetsuji Kametani Hiroko Kasai Etsuko Sato Toshio Suzuki 《Journal of Chemical Sciences》1988,100(2-3):91-111
For the purpose of organic syntheses of some corynanthe-type indole alkaloids, sesquiterpenes, and steroids, optically active
intermediates cyclopentanone 3-allylalcohol, α-methylene-γ-butylo lactones andtrans-hydrindanone-propionic acid, were synthesized from (R)- and (S)-isopropylideneglyceraldehyde derived fromD-mannitol andLascorbic acid, respectively, utilizing Claisen rearrangement as a key reaction. Actually total syntheses of natural alkaloids,
(-)-antirhine, (+)-dihydroantirhine and (-) dihydrocorynantheol were accomplished. 相似文献