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1.
Synthesis of 20S-protopanaxadiol 20-O-β-D-glucopyranoside, a metabolite of Panax ginseng glycosides, and compounds related to it 总被引:1,自引:0,他引:1
A preparative semi-synthetic method was developed to prepare 20S-protopanaxadiol 20-O-β-Dglucopyranoside (1), a metabolite of Panax ginseng glycosides. The 20-O-•-D-glucopyranosides of 20S-hydroxydammar-24-en-3,12-dione, 3β,20S-dihydroxydammar-24-en-12-one, and 3β,12α, 20S-trihydroxydammar-24-ene were synthesized for the first time.
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Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 364–369, July–August, 2006. 相似文献
2.
A method for preparative production of 3β,20S-dihydroxydammar-24-en-12-one 3,20-di-O-β-D-glucopyranoside (1), a glycoside from Panax japonicus, chikusetsusaponin-LT8 was developed. Chemical transformation of betulafolientriol, a component of Betula leaves extract, produced the 12-keto-20S-protopanaxadiol (3β,20S-dihydroxydammar-24-en-12-one) (2), exhaustive glycosylation of which by 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosylbromide (3) under Koenigs—Knorr reaction conditions with subsequent removal of protecting groups formed 3β,20S-dihydroxydammar-24-en-12-one
3,20-di-O-β-D-glucopyranoside (1). The principal glycosylation product was 3β,20S-dihydroxydammar-24-en-12-one 3-O-β-D-glucopyranoside if equimolar amounts of (2) and (3) were used.
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Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 44–48, January–February, 2006. 相似文献
3.
Molecular dynamics simulations on the structures and properties of ε-CL-20-based PBXs——Primary theoretical studies on HEDM formulation design 总被引:3,自引:0,他引:3
Five polymer bonded explosives (PBXs) with the base explosiveε-CL-20 (hexanitrohexaazaisowurtzitane), the most important high energy density compound (HEDC), and five polymer binders (Estane 5703, GAP, HTPB, PEG, and F2314) were constructed. Molecular dynamics (MD) method was employed to investigate their binding energies (Ebind), compatibility, safety, mechanical properties, and energetic properties. The information and rules were reported for choosing better binders and guiding formulation design of high energy density material (HEDM). According to the calculated binding energies, the ordering of compatibility and stability of the five PBXs was predicted as ε-CL-20/PEG > ε-CL-20/ Estane5703 ≈ε-CL-20/GAP > ε-CL-20/HTPB > ε-CL-20/F2314. By pair correlation function g(r) analyses, hydrogen bonds and vdw are found to be the main interactions between the two components. The elasticity and isotropy of PBXs based ε-CL-20 can be obviously improved more than pure ε-CL-20 crystal. It is not by changing the molecular structures of ε-CL-20 for each binder to affect the sensitivity. The safety and energetic properties of these PBXs are mainly influenced by the thermal capability (C°p) and density (ρ) of binders, respectively. 相似文献
4.
The 3-O-β-D-galactopyranosyl-20-O-β-D-glucopyranoside and 3-O-β-D-glucopyranosyl-20-O-β-Dgalactopyranoside of 3β,20S-dihydroxydammar-24-en-12-one, which are structural analogs of chikusetsusaponin-LT8 (1), a minor glycoside from Panax japonicus, were synthesized for the first time. 相似文献
5.
Agnieszka Wojtkielewicz Jadwiga Maj Lech Szczepaniak Jacek W. Morzycki 《Monatshefte für Chemie / Chemical Monthly》2011,14(2):59-65
Abstract
The unusual air oxidation of steroidal triols and diols in the presence of sodium hydride in THF is described. The initial oxidation product, ketone or aldehyde, frequently undergoes further transformations in the reaction medium. The course of the reaction depends on the stereochemistry of the substrate. For example, oxidation of (20R)-20-hydroxymethyl-6β-methoxy-3α,5α-cyclopregnane-16β,17α-diol with air/NaH afforded 6β-methoxy-23,24,25,26,27-pentanor-3α,5α-cyclofurostane-16α,17α-diol in 60% yield whereas similar reaction of (20R)-20-hydroxymethyl-6β-methoxy-3α,5α-cyclopregnane-16α,17α-diol gave 6β-methoxy-D-homo-16a-oxa-3α,5α-cycloandrostan-16-one in 30% yield. The objective of this preliminary study was to select alcohols susceptible to air/NaH oxidation and to establish the effect of conditions on the course of the reaction. 相似文献6.
Mohamed Alchihab Jacqueline Destain Mario Aguedo Jean-Paul Wathelet Philippe Thonart 《Applied biochemistry and biotechnology》2010,162(1):233-241
The production of γ-decalactone and 4-hydroxydecanoic acid by the psychrophilic yeast R. aurantiaca was studied. The effect of both compounds on the growth of R. aurantiaca was also investigated and our results show that γ-decalactone must be one of the limiting factors for its production. The
addition of gum tragacanth to the medium at concentrations of 3 and 4 g/l seems to be an adequate strategy to enhance γ-decalactone
production and to reduce its toxicity towards the cell. The production of γ-decalactone and 4-hydroxydecanoic acid was significantly
higher in 20-l bioreactor than in 100-l bioreactor. By using 20 g/l of castor oil, 6.5 and 4.5 g/l of γ-decalactone were extracted
after acidification at pH 2.0 and distillation at 100 °C for 45 min in 20- and 100-l bioreactors, respectively. We propose
a process at industrial scale using a psychrophilic yeast to produce naturally γ-decalactone from castor oil which acts also
as a detoxifying agent; moreover the process was improved by adding a natural gum. 相似文献
7.
M. I. Sikharulidze N. Sh. Nadaraia M. L. Kakhabrishvili 《Chemistry of Natural Compounds》2012,48(3):423-425
The semicarbazone and isonicotinoylhydrazone of 5α-pregn-2-en-20-one, which was prepared from 3β-acetoxy-5α-pregn-16-en-20-one, were synthesized for the first time. The antituberculosis activity of these and semicarbazones and isonicotinoylhydrazones of saturated, unsaturated, and adamantane-modified ketosteroids synthesized by us earlier was studied in vitro experiments. 相似文献
8.
The alterations of organic acids citrate, α-ketoglutarate, succinate, fumarate, malate production together with isocitrate
lyase activity as a glyoxalate shunt enzyme, and antibiotic production of Streptomyces sp M4018 were investigated in relation to changes in the glucose, glycerol and starch concentrations (5–20 g/L) after identification
as a strain of Streptomyces hiroshimensis based on phenotypic and genotypic characteristics. The highest intracellular citrate and α-ketoglutarate levels in 20 g/l
of glucose, glycerol, and starch mediums were 399.47 ± 4.78, 426.93 ± 6.40, 355.84 ± 5.38 ppm and 444.81 ± 5.12, 192.96 ± 2.26,
115.20 ± 2.87 ppm, respectively. The highest succinate, malate, and fumarate levels were also determined in 20 g/l of glucose
medium as 548.9 ± 11.21, 596.15 ± 8.26, and 406.42 ± 6.59 ppm and the levels were significantly higher than the levels in
glycerol and starch. Extracellular organic acid levels measured also showed significant correlation with carbon source concentrations
by showing negative correlation with pH levels of the growth medium. The antibiotic production of Streptomyces sp. M4018 was also higher in glucose medium as was the case also for organic acids when compared with glycerol. On the other
hand, there is no production in starch. 相似文献
9.
Evaluation of a novel ELISA for serotonin: urinary serotonin as a potential biomarker for depression
Nichkova MI Huisman H Wynveen PM Marc DT Olson KL Kellermann GH 《Analytical and bioanalytical chemistry》2012,402(4):1593-1600
Depression is a common disorder with physical and psychological manifestations often associated with low serotonin. Since
noninvasive diagnostic tools for depression are sparse, we evaluated the clinical utility of a novel ELISA for the measurement
of serotonin in urine from depressed subjects and from subjects under antidepressant therapy. We developed a competitive ELISA
for direct measurement of serotonin in derivatized urine samples. Assay performance was evaluated and applied to clinical
samples. The analytical range of the assay was from 6.7 to 425 μg serotonin/g creatinine (Cr). The limit of quantification
was 4.7 μg/g Cr. The average recovery for spiked urine samples was 104.4%. Average intra-assay variation was 4.4%, and inter-assay
variation was <20%. The serotonin analysis was very specific. No significant interferences were observed for 44 structurally
and nonstructurally related urinary substances. Very good correlation was observed between urinary serotonin levels measured
by ELISA and liquid chromatography tandem mass spectrometry (LC-MS/MS; ELISA = 1.16 × LC-MS/MS − 53.8; r = 0.965; mean % bias = 11%; n = 18). Serotonin was stable in acidified urine for 30 days at room temperature and at −20 °C. The established reference range
for serotonin was 54–366 μg/g Cr (n = 64). Serotonin levels detected in depressed patients (87.53 ± 4.89 μg/g Cr; n = 60) were significantly lower (p < 0.001) than in nondepressed subjects (153.38 ± 7.99 μg/g Cr). Urinary excretion of serotonin in depressed individuals significantly
increased after antidepressant treatment by 5-hydroxy-tryptophane and/or selective serotonin re-uptake inhibitor (p < 0.01). The present ELISA provides a convenient and robust method for monitoring urinary serotonin. It is suitable to monitor
serotonin imbalances and may be particularly helpful in evaluating antidepressant therapies. 相似文献
10.
A new high-performance liquid chromatography assay was developed for the determination of minocycline in plasma and brain.
A solid–liquid extraction procedure was coupled with a reversed-phase HPLC system. The system requires a mobile phase consisting
of acetonitrile:water:perchloric acid (26:74:0.25, v/v/v) adjusted to pH 2.5 with 5 M sodium hydroxide for elution through a RP8 column (250 × 3.0 mm, i.d.) with UV detection set
at 350 nm. The method proved to be accurate, precise (RSD < 20%) and linear between 0.15–20 μg mL−1 in plasma and 1–20 μg mg−1 in brain. The method was successfully applied to a blood-brain barrier minocycline transport study. 相似文献
11.
M. G. Voronkov A. V. Vlasov N. N. Vlasova 《Russian Journal of Organic Chemistry》2010,46(12):1838-1842
Reactions of acetyl iodide with pyridine at room temperature and with quinoline both at 20–25°C and on cooling to −50°C involve
dehydrohalogenation of acetyl iodide with formation of ketene and pyridinium or quinolinium iodides. The reaction of acetyl
iodide with pyridine at −5 to −50°C led to the formation of N-acetylpyridinium iodide. Benzoyl iodide reacted with both pyridine and quinoline at both −50°C and at 20–25°C to form stable
N-benzoylpyridinium and N-benzoylquinolinium iodides. The reaction of pyrrole with acetyl iodide under analogous conditions was accompanied by polymerization. 相似文献
12.
20S-Protopanaxadiol (3β,12β,20S-trihydroxydammar-24-ene) 3-, 12-, and 20-O-β-D-galactopyranosides were synthesized for the first time. Condensation of 12β-acetoxy-3β,20S-dihydroxydammar-24-ene (1) and 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosylbromide (α-acetobromogalactose) (2) under Koenigs–Knorr conditions with subsequent removal of the protecting groups resulted in regio- and stereoselective formation
of 20S-protopanaxadiol 3-O-β-D-galactopyranoside, an analog of the natural ginsenoside Rh2. Glycosylation of 12β,20S-dihydroxydammar-24-en-3-one (5) by 2 with subsequent treatment of the reaction products with NaBH4 in isopropanol and deacetylation with NaOMe gave 20S-protopanaxadiol 12- and 20-O-β-Dgalactopyranosides. 相似文献
13.
Thomas Kavc Wolfgang Kern Christian Zenz Guünther Leising Gerald Kranzelbinder Eric Toussaere 《Monatshefte für Chemie / Chemical Monthly》2001,20(2):531-540
Poly-(4-vinylbenzyl-thiocyanate) (PVBT) was investigated as a photoreactive polymer which changes its refractive index upon UV irradiation as is required for the
production of phase gratings. After UV irradiation, the refractive index of PVBT films increased from nD
20 = 1.629 to nD
20 = 1.660 (Δn = +0.031). The change in the refractive index resulted mainly from the photoinduced isomerization of thiocyanate
(SCN) to isothiocyanate (NCS) groups. It was possible to modify irradiated PVBT with 1-naphthylmethyl amine which lead to a further increase of the refractive index. Both the isomerization and the modification
were followed with FTIR spectroscopy. This modification of the irradiated zones also yields an advantageous stabilization
of phase gratings enscribed in PVBT. The investigations were carried out in the realm of novel organic distributed feedback (DFB) lasers. 相似文献
14.
A kind of erbium hexacyanoferrate (ErHCF)-modified carbon ceramic electrodes (CCEs) fabricated by mechanically attaching ErHCF
samples to the surface of CCEs derived from sol–gel technique was proposed. The resulting modified electrodes exhibit well-defined
redox responses with the formal potential of +0.215 V [vs saturated calomel electrode (SCE)] at a scan rate of 20 mV s−1 in 0.5 M KCl (pH 7) solution. The voltammetric characteristics of the ErHCF-modified CCEs were investigated by voltammetry.
Attractively, the ErHCF-modified CCEs presented good electrocatalytic activity with a marked decrease in the overvoltage about
400 mV for l-cysteine oxidation. The calibration plot for l-cysteine determination was linear at 5.0 × 10−6–1.3 × 10−4 M with a linear regression equation of I(A) = 0.558 + 0.148c (μM) (R
2 = 0.9989, n = 20), and the detection limit was 2 × 10−6 M (S/N = 3). At last, the ErHCF-modified CCEs were used for amperometric detection of l-cysteine in real samples. 相似文献
15.
Sol and Gel state properties of aqueous gelatin solutions of concentrations 4%, 6%, 8% and 10% (w/v) have been investigated
through dielectric relaxation studies done at various temperatures in the range T=20–60 °C carried out over a frequency range f=20 Hz–10 MHz and no relaxation of any nature was observed. The sharp transition observed at the gelation temperature T
gel provided an excellent matching with the same measured through differential scanning calorimetry (DSC). The capacitance (C
p) values above f=100 kHz became increasingly negative as the gel was melted to the sol state. However, in the gel state C
p was found to be almost independent of temperature for frequencies above 100 kHz. At frequencies lower than 10 kHz, C
p measured was ∼105 F, implying pronounced interfacial polarization either due to electro-chemical reaction or because of ions getting trapped
at some interface within the bulk.
Received: 10 February 1997 Accepted: 2 September 1997 相似文献
16.
V. N. Odinokov I. V. Galyautdinov A. A. Fatykhov L. M. Khalilov 《Russian Chemical Bulletin》2000,49(11):1923-1924
A new phytoecdysteroid,viz, 2-deoxy-3-epi-4β, 20-dihydroxycedysone ((20R,22R)-3α,4β 14α,20,22,25-hexahydroxy-5β-cholest-7-en-6-one), named coronatasteronc, was isolated fromSerratula coronata and identified by NMR spectroscopy.
Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1954–1955, November, 2000. 相似文献
17.
A novel calix[4]arene-based fluorescent chemosensor bearing a 2-aminopyridine moiety and a naphthalenic fluorophore was synthesized
The chemical structure of the product was elucidated by FT-IR, MS-FAB, NMR and elemental analyses. Then, the properties and
identification mechanism of the synthesized chemosensor were investigated. The results show that the chemosensor exhibits
selective fluorescent quenching in the presence of aromatic organic acid in acetonitrile solution, and that the binding ability
of the chemosensor with organic acid is in the order of p-cyanic-benzyl acid > p-chloric-benzyl acid > p-methoxyl-benzyl acid > benzyl acid.
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Translated from Journal of South China University of Technology (Natural Science Edition), 2007, 35(4): 20–24 [译自: 华南理工大学学报(自然科学版)] 相似文献
18.
A. A. Kicha N. V. Ivanchina T. T. T. Huong A. I. Kalinovsky P. S. Dmitrenok P. Q. Long 《Russian Chemical Bulletin》2010,59(11):2133-2136
A new minor asterosaponin (20S)-6-O-{β-d-fucopyranosyl-(1→2)-[β-d-fucopyranosyl-(1→4)-β-d-quinovopyranosyl-(1→2)]-β-d-quinovopyranosyl-(1→3)-β-d-quinovopyranosyl}-3β,6α,20-trihydroxycholest-9(11)-en-23-one 3-sulfate (archasteroside C) was isolated from the starfish
Archaster typicus collected in shallow coastal waters of Vietnam. The structure of archasteroside C was determined by 2D NMR spectroscopy and
electrospray ionization (ESI) tandem mass spectrometry. 相似文献
19.
Y. Ghasemi M. Tabatabaei Yazdi A. Dehshahri H. Niknahad S. Shokravi M. Amini A. Ghasemian M. A. Faramarzi 《Chemistry of Natural Compounds》2006,42(6):702-705
The potential of Nostoc ellipsosporum for biotransformation of hydrocortisone was studied. The microorganism was isolated during a screening program from soil
samples collected from the paddy fields in the north of Iran and had not been previously examined for this purpose. The biotransformation
yielded 11β,17α,20β, 21-tetrahydroxypregn-4-en-3-one and 11β-hydroxyandrost-4-ene-3,17-dione. Both of the metabolites were purified chromatographically and characterized using instrumental
analyses.
Published in Khimiya Prirodnykh Soedinenii, No. 6, pp. 572–574, November–December, 2006. 相似文献
20.
I. A. Sukhina R. P. Mamedova M. A. Agzamova M. I. Isaev 《Chemistry of Natural Compounds》2007,43(2):159-161
The two trisdesmoside cycloartane glycosides astragaloside VII and cyclotrisectoside were isolated from Astragalus dissectus (Leguminosae) and identified. The latter was 20R,25-epoxy-24S-cycloartan-3β,6α,16β,24-tetraol 3-O-β-D-xylopyranoside-6,24-di-O-β-D-glucopyranoside and was a new natural compound.
Presented at the Sixth International Symposium on the Chemistry of Natural Compounds (SCNC, Turkey, Ankara, 28–29 June 2005).
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Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 132–134, March–April, 2007. 相似文献