首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到10条相似文献,搜索用时 56 毫秒
1.
    
The isomerization of 5-vinyl-2-norbornene (1) has been studied in the presence of Co (R1-COCHCOR2)x–Et6–yAl2Cly (x=2, 3; y=2–4) catalytic systems. Co(acac)2–AlEt3 and Co(acac)3–AlEt3 systems isomerize1 to 5-ethylidene-2-norbornene (2), whereas the Co(PhCOCHCOPh)2–AlEt3 system selectively forms 3-vinylnortricyclene (3).2 is always accompanied by formation of ethylidene norbornane (4). A possible mechanism for formation of products is proposed.  相似文献   

2.
    
A new alkaloid — leuconine — has been isolated from the epigeal parts ofAconitum leucostomum andA. septentrionale, and its structure has been established on the basis of spectral characteristics.Institute of Chemistry of Plant Substances, Uzbekistan Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 538–540, September–October, 1992.  相似文献   

3.
Summary Structure (I) is proposed for arnifolin — a sesquiterpene lactone fromArnica foliosa Nutt. andArnica montana L.All-Union Scientific-Research Institute for Medicinal Plants. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 270–272, May–June, 1971.  相似文献   

4.
    
Summary From the hydrocarbon fractions of the oleoresins ofPicea obovata Ledb andPinus koraensis Sieb. Zucc. a new monocyclic diterpene hydrocarbon — neocembrene — has been isolated, and a structure has been proposed for it.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 694–698, November–December, 1970.  相似文献   

5.
A new approach is proposed to the synthesis of 11-oxododeca-3,6-diynoic acid — the acyclic precursor of a macrolide component of pheromones ofOryzaephilus mercator andO. surinamensis — from the readily available tetrahydropyran or allylacetone via the intermediate 5-bromo-2,2-ethylenedioxypentane.Institute of Organic Chemistry, Urals Division, Russian Academy of Sciences, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 288–292, March–April, 1993.  相似文献   

6.
    
Ulocladols A and B — new exometabolites having a mixed sesquiterpenoid-polyketide nature that are structurally close to the host-specific toxins ofAlternaria citri — have been isolated from the deuteromyceteUlocladium chartarum. Both substances inhibit the growth of cotton seeds.All-Union Scientific Research Institute of Phytopathology, Moscow Province, Golitsyno. M. V. Lomonosov Moscow State University. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 642–648, September–October, 1991.  相似文献   

7.
Summary 1. The content of total alkaloids in the hypogeal parts ofAndrachne rotundifolia C. A. Mey. (family Euphorbicease) is 0.2–0.3% and in the epigeal parts 0.06–0.08%.The total alkaloids in both the hypogeal and the epigeal parts ofAndrachne rotundifolia consist of five or six non-phenolic bases.2. Three individual substances have been isolated: andrachnine C11H17NO2, which is a new alkaloid; base (II), giving a perchlorate with mp 139°–140° C; and base (III) with mp 135°–136° C.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 4, pp. 257–260, 1966  相似文献   

8.
Summary From the neutral fraction of an acetone extract of the roots of plants of the genusFerula,F. gummosa Boiss.,F. pseudoreoselinum Rgl. et Schmalh. (K-Pol.) andF. Samarkandica Eug. Kor., we have isolated a coumarin gummosin with the composition C24H30O4, mp 176–177°C, [a]D –54°C. The structure of gummosin corresponds to formula (III).With respect to structure, gummosin is a spatial isomer of farnesiferol A; it differs from the latter by the fact that the secondary OH group in gummosin is axial.Khimiya Prirodynkh Soedinenii, Vol. 2, No. 6, pp. 383–387, 1966  相似文献   

9.
We have studied the uptake of237Np in marine plants and animals belonging to several phyla, and collected samples from the end of January 1986 to March 1986, in a sampling station situated near the outlet of the irradiated fuel reprocessing plant at La Hague.We determined the237Np by neutron activation analysis. This method is very sensitive, with a limit of detection of 5×10–10 mg, 1.3×10–2 mBq. The method consists of the following steps:Reduction of the neptunium to the tetravalent state by treatment with a mixture of hydrazine sulfate and ferrous iron-chromatographic separations on Dowex 1×10 resin in a nitric medium, then in a hydrochloric medium-neutron irradiation in a nuclear reactor-purification of the neptunium by chromatography on Dowex 1×10 resin in a nitric then hydrochloric medium-measurement of the isotope238Np by gamma ray spectrometry using a Ge(Li) detector. The species were collected at Goury, at the northwest extremity of the Cotentin Peninsula, 5 km from the outlet of the reprocessing plant at La Hague. The levels of237Np were as follows: red algaeCorallina officinalis 64 mBq kg–1 wet weight; andChondrus crispus 18 mBq kg–1 wet weight; the spongeHalichondria panicea 14 mBq kg–1 wet weight; the ascidianDendrodoa grossularia 12 mBq kg–1 wet weight. The bivaive molluscsPatella vulgata andGibbula umbilicalis (the flesh ofP. vulgata andG. umbilicalis: 4 and 7 mBq kg–1 wet weight respectively) also prove to be interesting biological indicatorsThe transfer modes of237Np to the various species as a function of their trophic levels are discussed as well as the distribution among the organs in the species consumed and the radiological impact of human consumption.  相似文献   

10.
(E)-Dodec-3-en-l-yl acetate — the main component of the sex pheromones ofScrobipalpa ocellatella andScrobipalpopsis solanivora — has been obtained by a three-stage synthesis from decanal and malonic acid. The overall yield of pheromone was 33% calculated on the initial aldehyde.A. S. Sadykov Institute of Bioorganic Chemistry, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 682–683, September–October, 1988.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号