首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The quinic acid caffeates of the flowers ofHelichrysum italicum and the herbage ofAchillea cartilaginea have been studied with the use of HPLC,13H NMR spectroscopy, and chemical transformations.All-Union Research Institute of Medicinal Plants Scientific-Production Association, Moscow. Translated from Bioorganicheskaya Khimiya, No. 1, pp. 50–55, January–February, 1992.  相似文献   

2.
Summary Using the optical densitometry of thin-layer chromatograms, the amounts of triterpenoids of the dammarane series have been determined in the unsaponifiable fractions of ethereal extracts from the leaves of Far Eastern species of birch:Betula costata, B. mandshurica, B. dahurica, B. platyfolia, andB. kamtschatica. Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, USSR, Vladivostok Academy of Sciences. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 349–353, May–June, 1977.  相似文献   

3.
29Si NMR peaks due to species with the double four-membered ring siloxane backbone composed of both Si(O)4/2 and CH3Si(O)3/2 units, (CH3) n Si8O 20 – n /(8 – n) – (n=1–3), formed by co-hydrolysis of tetraethoxysilane and methyltriethoxysilane in the presence of tetramethylammonium ions in methanol have been assigned. It has been found that 29Si NMR peaks due to Si(OSi)3(O) units shift to lower frequencies by replacement of the adjacent Si(O)4/2 units by CH3Si(O)3/2 units, in other words, with increasing m value in Si[OSi(O)3]3 – m [OSi(CH3) (O)2] m (O) (m=0–2). Peaks from CH3 Si(OSi)3 units in the species have also appeared as separated due to the kind of neighbor structural units. On the basis of the assignments, positions of CH3Si(O)3/2 units in the cubic octameric siloxane framework of (CH3) n Si8O 20 – n /(8 – n) – (n=2, 3), for both of which three isomers are present, have been estimated.  相似文献   

4.
The uptake and release kinetics of137Cs from water by the tropical fishBrachydanio rerio has been studied under controlled laboratory condition. The accumulation of this radionuclide from food was avoided by feeding the fishes separately in an inactive environment. A steep inverse dependence of bioconcentration factor (BCF) with potassium concentration has been observed. This can formally be described by the equation BCF=5.2 · [K+]–0.44. The elimination rate constant K in fresh water conditions has been found to have a magnitude of 0.014±0.03 d–1 which corresponds to a biological half-life of 51±10 days. The uptake and release kinetics ofBrachydanio rerio has been compared with earlier studies of fresh water fishes.  相似文献   

5.
Summary 1. The polarographic behavior of haploperine, haplopine, haplophyllidine, and perforine in Britton-Robinson buffer solutions and in (C2H5)4NOH solutions has been studied. Optimum conditions for their quantitative determination in solutions within the range of concentrations from 5×10–4 to 1×10–2 M have been found.2. A method for the separate quantitative determination of the alkaloids in the seeds ofH. perforatum has been developed.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 5, pp. 333–337, 1966  相似文献   

6.
    
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   

7.
Summary Di-2-ethylhexyl phthalate has been isolated from the neutral lipids fraction of the culture liquid of the fungusVerticillium dahliae Kleb. Its1H and13C magnetic resonance spectra have been obtained, and an assignment of the signals has been made.On the basis of their UV, IR, and ESR spectra, the chromogenic components of the neutral lipid fractions have been assigned to the melanins.V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 689–693, November–December, 1975.  相似文献   

8.
The known cembrenolide sarcophin and its new acetoxy derivative — 13-acetoxy-7,8-epoxycembra-1(15),3,11-trien-2,16-olide — have been isolated from the soft coralLobophytum sp.. The compounds isolated are inhibitors of the activity of Na+K+-ATPase and are membranotropic agents. The structures of the compounds have been shown on the basis of the results of NMR spectroscopy.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 762–765, November–December, 1990.  相似文献   

9.
Squalene, 35-methoxyho-6-ene-32R,33R,34S-triol, hop-22(29)-ene, and hopan-22-ol have been isolated fromAcetobacter sp. VSB 917. The structures of the substances isolated and of the 35-methoxyhop-6-ene-32R,33R,34S-triol triacetate obtained have been established by IR, mass, and1H and13C NMR spectroscopies.Vitaminy Scientific-Production Association, Moscow. Translated from Khimiya Prirodnykh Soedinenii, Nos. 3,4, pp. 367–372, May–August, 1992.  相似文献   

10.
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   

11.
The influence of a number of bivalent metals on the activity ofStreptomyces atratus glucose isomerase has been studied. Mg2+ ions are activators and Co2+ ions are stabilizers of the glucose isomerase activity. The effective kinetic parameters for the action of the enzyme have been determined.Institute of Microbiology, Uzbek Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 838–842, November–December, 1991.  相似文献   

12.
Two trail attractants for the termiteR. lucifugus have been isolated from the plantZizyphus jujuba: - and -bisabolenes. The threshold concentrations of the actions of these substances amounts to 10–9 g/liter. -Bisabolene in the range of concentrations of 1–10–6 g/liter is a powerful repellant for termites.Institute of Physiologically Active Substances, Academy of Sciences of the USSR, Chernogolovka. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 416–419, May–June, 1989.  相似文献   

13.
Coumaris ofHaplophyllum obtusifolium Ledeb. — obtusinin, capensin, and fraxetin 7-O--D-glucopyranoside — have been investigated by13C NMR spectroscopy. Several distinctive features of their NMR spectra have been observed. A complete assignment of the13C NMR spectra of these coumarins has been made and their structures have been confirmed.Institute of the Chemistry of Plant Substances, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 796–799, November–December, 1987.  相似文献   

14.
    
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   

15.
    
Berberine, palmatine, jatrorrhizine, oxyacanthine, berbamine, reticuline, obaberine, isocorydine, thalicmidine, and the new base berberal (I) have been isolated from leaves and young shoots ofBerberis heterobotrys Wolf. The structure of berberal has been established by a study of its1H and13C NMR spectra and measurement of intramolecular NOEs, and also by mass-spectrometric analysis.Institute of the Chemistry of Plant Substances, Uzbekistan Academy of Sciences, Tashkent. Andizhan State Medical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 869–873, November–December, 1993.  相似文献   

16.
Summary The oil of the seeds ofRindera oblongifolia, family Boraginaceae, growing in Central Asia, has been studied for the first time. Among the acids of the triglycerides of the oil five types of monoenoic acid differing by the length of the carbon chain but having the same length of the terminal carbon chain — 18:19, 20:111, 22:113, 24:115, and 26:117 — have been detected for the first time. This is the first time that the last of these acids has been found in a seed oil of this family.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 26–29, January–February, 1976.  相似文献   

17.
Four new triterpene glycosides of the holostane series have been isolated from an alcoholic extract of the economically important Pacific Ocean holothurianCucumaria japonica: cucumariosides A1-2 (I), A2-3 (II), A2-4 (III), and A4-2 (IV). The structures of these substances have been established by the methods of carbohydrate chemistry and13C NMR spectroscopy.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 787–793, November–December, 1990.  相似文献   

18.
    
The structure of the new germacranolide shoanchalin C (C15H22O4, mp 203–205°C) isolated fromArtemisia fragans has been established on the basis of spectroscopic (IR,1H and13C NMR) results.V. L. Komarov Institute of Botany, Academy of Sciences of the Azerbaidzhan SSSR, Baku. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 787–790, November–December, 1985.  相似文献   

19.
Summary The biosynthesis of the alkaloids ofAmmodendron karelinii Fisch. et Mey has been studied by feeding the plant with labelled [1,5-14C]cadaverine. It has been shown that cadaverine is a precursor of anagyrine, pachycarpine, ammodendrine, N-methylcytisine, and cytisine. Possible routes of interconversions have been considered by feeding the plant with the tritium-labelled [3H]pachycarpine, [3H]lupanine, [3H]anagyrine, and [3H]ammodendrine.V. I. Lenin Tashkent State University. Institute of Plant Biochemistry, Academy of Sciences of the GDR, Halle. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 247–250, March–April, 1977.  相似文献   

20.
Reserpine, ajmaline, serpentine, ajmalicine, isoreserpiline, and other alkaloids have been isolated from the roots ofRauwolfia cambodiana Pierre ex Pitard,R. verticillata Baill. andR. serpentina Benth.R. vomitoria Afz. was the richest in alkaloids.Leningrad Institute of Pharmaceutical Chemistry. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 813–816, November–December, 1991.  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