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1.
P. Kh. Yuldashev B. Tashkhodzhaev K. K. Turgunov M. M. Mirzaeva 《Chemistry of Natural Compounds》2011,46(6):924-928
The bisindole compound 2β,16α,2′β,16′β(H)-tetrahydronordihydrotoxiferine consisting of two diastereoisomeric deoxytetrahydronorfluorocurarine moieties was isolated
from the reduction mixture of the alkaloid norfluorocurarine. 16-Deformyl-2,16,17,20-tetrahydro-20,21-dehydronorfluorocurarine
was produced by dehydrogenation of norfluorocurarine; N(β)-methyldihydrodefluorocurarine, by hydrogenation of fluorocurarine. The structures of the synthesized compounds were established
by x-ray structure analyses. The configurations of the asymmetric centers in 2β,16α,2′β,16′β(H)-tetrahydronordihydrotoxiferine were determined as 2S,3S,7R,15S,16R,2′S,3′S,7′R,15′S,16′S. Inversion to the R-configuration at the C15 center was observed in N(β)-methyldihydrodefluorocurarine whereas the configurations 3S and 7R were retained. Atom C2 adopted the S-configuration in 16-deformyl-2,16,17,20-tetrahydro-20,21-dehydronorfluorocurarine. 相似文献
2.
Czeslawa Orlewska Rafat M. Shaker Martin Dees Hans-Hartwig Otto 《Monatshefte für Chemie / Chemical Monthly》2000,6(4):889-893
The reaction between push-pull olefins of the acyloxymethylidene-malononitrile type and α, β-unsaturated hydrazones affords selectively 5-alkyl-2-cyano-6-(N′,N′-dimethylhydrazono)-hexa-2,4-dienenitriles. No [4+2]-cycloaddition products were detected. The structure elucidation of the obtained compounds and possible reaction mechanisms are discussed. 相似文献
3.
V. S. Renzik V. D. Akamsin I. V. Galyametdinova S. G. Fattakhov B. E. Ivanov 《Russian Chemical Bulletin》1999,48(5):979-983
Dialkyl β-(2-aroxyethylamino)ethylphosphonates,N-[β-(2-methoxyphenoxy)ethyl]-N′-[β-(diethoxyphosphoryl)ethyl]-α,ω-diaminoalkanes, and diethyl β-(N-arylpiperazino)ethyl-phosphonates were synthesized by the reactions of dialkyl vinylphosphonates with β-aroxyethylamines,N-[β-(2-methoxyphenoxy)ethyl]-α,ω-diaminoalkanes, andN-aryl-piperazines, respectively. The compounds synthesized exhibit hypotensive and α-adrenolytic activities.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 987–991, May 1999. 相似文献
4.
Czeslawa Orlewska Rafat M. Shaker Martin Dees Hans-Hartwig Otto 《Monatshefte für Chemie / Chemical Monthly》2000,131(8):889-893
Summary. The reaction between push-pull olefins of the acyloxymethylidene-malononitrile type and α, β-unsaturated hydrazones affords
selectively 5-alkyl-2-cyano-6-(N′,N′-dimethylhydrazono)-hexa-2,4-dienenitriles. No [4+2]-cycloaddition products were detected.
The structure elucidation of the obtained compounds and possible reaction mechanisms are discussed.
Received March 9, 2000. Accepted March 20, 2000 相似文献
5.
H. Krajian N. Mofaddel D. Villemin P. L. Desbène 《Analytical and bioanalytical chemistry》2009,394(8):2193-2201
Enantioseparation of 6,6′-dibromo-1,1′-binaphthyl-2,2′-diol (DBBD) by cyclodextrin-modified capillary zone electrophoresis
(CD-CZE) was studied using the three native α, β, and γ cyclodextrins, the three hydroxypropylated cyclodextrins (2-hydroxypropyl-α,
β, and γ), heptakis-2,6-di-O-methyl-β-CD (DM-β-CD), and heptakis-2,3,6-tri-O-methyl-β-cyclodextrin (TM-β-CD). First, the acidity constants of DBBD were determined using capillary electrophoresis, before
performing enantioseparation. The influence of the concentrations of the studied cyclodextrins on the enantioseparation was
explored and the experimental optimal concentrations were determined and compared to the theoretical optimal concentrations.
Moreover, the apparent complexation constants between each studied cyclodextrin and the two DBBD enantiomers were evaluated
using a non-linear curve fitting method and three linear plotting methods (x-reciprocal, y-reciprocal and double reciprocal). For TM-β-CD, the order of migration of the enantiomers of DBBD reversed as a function
of TM-β-CD concentration. The influence of the nature of methylated cyclodextrin derivatives (methyl-β-CD (M-β-CD) and DM-β-CD)
was then studied. Inversion of the order of migration of the enantiomers of DBBD was observed for DM-β-CD, whereas the S enantiomer of DBBD always migrated first for M-β-CD. 相似文献
6.
A series of new side-chain liquid crystalline polymers containing chenodiol residue derived from 24-[4′-hydroxybiphenyl-4-yl-4-(allyloxy)benzoyloxy]-3α,7α-di{n-[4′-(4-ethoxybenzoyloxy)biphenyl-4-yloxy]-n-oxoalkanoyloxy}-5β-cholane was designed and prepared. The chemical structures of the monomer and polymer were confirmed by Fourier transform
infrared and 1H NMR spectra. The mesomorphic properties of monomer and polymer were investigated by differential scanning calorimetry, thermogravimetric
analysis, polarizing optical microscopy, and X-ray diffraction. The side-chain liquid crystalline polymers revealed wide mesophase
temperature range and high thermal stability, and they showed nematic liquid crystalline phase. The influence of flexible
space group length on thermal properties and specific rotation was examined. 相似文献
7.
K. K. Uteniyazov Z. Saatov N. D. Abdullaev M. G. Levkovich 《Chemistry of Natural Compounds》1998,34(4):469-473
Four compounds of cycloartane nature have been isolated from the roots ofAstragalus globiceps Bunge. Their structures have been established on the basis of spectral characteristics and chemical transformations. Cyclosieversiosides
E and F and astrasieversianin III have been described previously. Cycloglobiceposide A has now been investigated for the first
time and found to be 20R, 24S-epoxycycloartane-3β, 6α, 16β, 25-tetraol 3-0-(2′-O-acetyl-β-D-xylopyranoside) 6′-O-acetyl-β-D-glucopyranoside).
Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (371) 240
64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 509–514, July–August, 1998. 相似文献
8.
I. S. Levina L. E. Kulikova E. V. Shulishov I. P. Klimenko A. V. Kamernitskii Yu. V. Tomilov 《Russian Chemical Bulletin》2006,55(11):2119-2121
4′,4′-Dimethyl[16α,17α]spiropentanopregn-4-ene-3,20-dione was synthesized. The addition of diazo-2,2-dimethylcyclopropane
generated from N-(2,2-dimethylcyclopropyl)-N-nitrosourea to 16,17-didehydropregnenolone acetate occurs regio-and stereospecifically to give 3β-acetoxy-1′,1′-dimethyl-20-oxopregn-5-ene-[16α,17α;7′,6′]-4′,
5′-diazaspiro[2.4]-hept-4′-ene in high yield. Its thermolysis affords a spiropentane-containing steroid, which is transformed
into the target diketone. The anti position of the gem-dimethyl group in the fused spiropentane fragment is evident from the X-ray diffraction study of the final product.
Dedicated to Academician O. M. Nefedov on the occasion of his 75th birthday.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2040–2042, November, 2006. 相似文献
9.
N. V. Ivanchina T. V. Malyarenko A. A. Kicha A. I. Kalinovskii P. S. Dmitrenok 《Russian Chemical Bulletin》2008,57(1):204-208
Nine steroidal compounds including three new steroidal glycosides, viz., sodium (24S)-3,24-di-O-(β-D-xylopyranosyl)-5α-cholestane-3β,6β,8,15α,24-pentol 15-sulfate (fuscaside A), (24S)-3,24-di-O-(β-D-xylopyranosyl)-5α-cholestane-3β,6β,8,15α,24-pentol (fuscaside B), and (22E,24R)-24-O-(β-D-xylopyranosyl)-5α-cholest-22-ene-3β,6α,8,15β,24-pentol (desulfated minutoside A); three previously known glycosides, viz., distolasterosides D1 and D2 and pycno-podioside A; two previously known polyhydroxysteroids, viz., 5α-cholestane-3β,6α,8,15β,16β,26-hexaol and 5α-cholestan-3β,4β,6α,7⇇8,15β,16β,26-octol; and the known sodium 24,25-dihydro-marthasterone
3-sulfate were isolated from the Far-Eastern starfish Lethasterias fusca. The structures of these compounds were elucidated by NMR spectroscopy and mass spectrometry.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 196–200, January, 2008. 相似文献
10.
The mechanism was established for annelation ([2+4] cyclocondensation) of Schiff bases or azomethines by β-dicarbonyl and
β,β′-tricarbonyl compounds in amphiprotic media. The condensation was found to be a self-catalyzed pericyclic process achieved
through six-membered transition states. The key reaction intermediates are dipoles of quaternized azomethine ions and enol-anions
of the β-dicarbonyl and β,β′-tricarbonyl compounds, which display 1,4-dipolarophilicity.
Dedicated to Academician A. A. Akhrem of the Belarus Academy of Sciences on the Occasion of His Ninety-Fifth Birthday
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 335–346, March, 2008. 相似文献
11.
O. A. Luk'yanov G. A. Smirnov S. V. Nikitin A. Z. Lisitsin 《Russian Chemical Bulletin》1999,48(1):124-130
Some characteristic features of reactions ofN-(β-hydroxyalkyl)-N′-hydroxydiazeneN-oxide salts with various α- and β-functionalized alkyl halides were established. Some α-and β-functionalizedN-(β-hydroxyalkyl)-N′-alkoxydiazeneN-oxides and e ethylenebis[N-(β-hydroxyalkyl)-N′-oxydiazeneN-oxides] were synthesized for the first time.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 123–129, January, 1999. 相似文献
12.
Ellagic acid derivatives from the stem bark of <Emphasis Type="Italic">Dipentodon sinicus</Emphasis>
Ellagic acid derivatives were isolated from Dipentodon sinicus and their structures were identified as 3,3′,4′-tri-O-methylellagic acid (1), 3,3′-di-O-methylellagic acid (2), 4,4′-di-O-methylellagic acid (3), 3,3′-di-O-methylellagic acid-4′-O-α-L-rhamnopyranoside (4), 3,3′,4′-tri-O-methylellagic acid-4′-O-β-D-glucopyranoside (5), 3,3′-di-O-methylellagic acid-4′-O-β-D-glucopyranoside (6), and ellagic acid (7). All the compounds were isolated for the first time from the title plant.
Published in Khimiya Prirodnykh Soedinenii, No. 2, pp. 106–107, March–April, 2007. 相似文献
13.
Five ellagic acid glycosides were isolated from Aphananthe aspera and their structures were identified as 3-O-methylellagic acid-4′-O-α-L-rhamnopyranoside (1), 3-O-methylellagic acid-4′-O-β-D-xylopyranoside (2), 3,3′-di-O-methylellagic acid-4′-O-β-D-xylopyranoside (3), 3,3′, 4-tri-O-methylellagic acid-4′-O-β-D-glucopyranoside (4), and 3,3′-di-O-methylellagic acid-4′-O-α-L-rhamnopyranoside (5) on the basis of spectroscopic analysis. Compound 1 is new, and all the compounds were isolated for the first time from the title plant.
Published in Khimiya Prirodnykh Soedinenii, No. 5, pp. 458–459, September–October, 2007. 相似文献
14.
Galesio M Mazzarino M de la Torre X Botrè F Capelo JL 《Analytical and bioanalytical chemistry》2011,399(2):861-875
A comparison between ultrasonication and microwave irradiation as tools to achieve a rapid sample treatment for the analysis
of banned doping substances in human urine by means of gas chromatography–mass spectrometry (GC–MS) was performed. The following
variables were studied and optimised: (i) time of treatment, (ii) temperature, (iii) microwave power and (iv) ultrasonic amplitude.
The results were evaluated and compared with those achieved by the routine method used in the World Anti-Doping Agency (WADA)
accredited Antidoping Laboratory of Rome. Only under the effect of the ultrasonic field was it possible to enhance the enzymatic
hydrolysis reaction rate of conjugated compounds. Similar reaction yield to the routine method was achieved after 10 min for
most compounds. Under microwave irradiation, denaturation of the enzyme occurs for high microwave power. The use of both ultrasonic
or microwave energy to improve the reaction rate of the derivatisation of the target compounds with trimethyliodosilane/methyl-N-trimethylsilyltrifluoroacetamide (TMSI/MSTFA/NH4I/2-mercaptoethanol) was also evaluated. To test the use of the two systems in the acceleration of the reaction with TMSI,
a pool of 55 banned substances and/or their metabolites were used. After 3 min of ultrasonication, 34 of the 55 compounds
had recoveries similar to those obtained with the classic procedure that lasts for 30 min (Student’s t test, n = 5), 18 increased to higher silylation yields, and for the compounds 13β,17α-diethyl-3α,17β-dihydroxy-5α-gonane (norboletone
metabolite 1), metoprolol and metipranolol the same results were obtained increasing the ultrasonication time to 5 min. Similar
results were obtained after 3 min of microwave irradiation at 1,200 W. In this case, 30 of the 55 compounds had recoveries
similar to the classic procedure (Student’s t test, n = 5) whilst 18 had higher silylation yields. For the compounds 3α-hydroxy-1α-methyl-5α-androstan-17-one (mesterolone metabolite
1), 17α-ethyl-5β-estrane-3α,17β,21-triol (norethandrolone metabolite 1), epioxandrolone, 4-chloro-6β,17β-dihydroxy-17α-methyl-1,4-androstadien-3-one
(chlormetandienone metabolite 1), carphedon, esmolol and bambuterol the same results were obtained after 5 min under microwave
irradiation. 相似文献
15.
J. E. Algie 《Colloid and polymer science》1969,234(2):1069-1078
Summary This paper contains data on the dielectric properties of wool with a range of water contents up to 30%, at temperatures of
0.5°, 21°, 32°, 48°, 70°, and 90 °C and for frequencies from 80 c/sec to 1.6 Mc/sec.
The dielectric loss data can be analysed into three absorption bands α, α′ andβ. Theα absorption is probably due to the motion of main chains, the α′ band is due to adsorbed water and theβ band is probably associated with the motion of side chains.
Water acts as a plasticiser and it is shown that a plot of the dielectric dispersion against water content does not show a
discontinuity indicating that there is no abrupt change in the nature of the absorbed water. 相似文献
16.
Levoglucosenone reacts with α-aminoazoles to yield azolo[1,5-a]pyrimidine systems fused with a carbohydrate fragment. The reaction oocurs much more smoothly than in the case of other α,β-unsaturated
ketones. The reactions of levoglucosenone with β-dicarbonyl compounds (dimedone, barbituric acid) in the presence of a base
results in the pyran ring closure, which has never been observed earlier in reactions of β-dicarbonyl compounds with α,β-unsaturated
ketones under the conditions of basic catalysis. The structures of products were established by IR and NMR spectroscopy.
For Part 3, see Ref. 1.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 553–558, March, 1997. 相似文献
17.
Chusaksri S Sutthivaiyakit S Sutthivaiyakit P 《Analytical and bioanalytical chemistry》2006,384(5):1236-1245
A confirmatory method for the determination of organochlorine pesticides (OCPs) and their metabolites (endrin, α-endosulfan,
β-endosulfan, endosulfan sulfate, heptachlor, heptachlor epoxide, 2,4′-DDD, 4,4′-DDD, 2,4′-DDE 4,4′-DDE, 2,4′-DDT, and 4,4′-DDT)
in surface waters using liquid chromatography /APCI/tandem mass spectrometry has been developed. Chromatographic separation
was carried out on a ChromSpher 5 Pesticide column using a gradient elution with mobile phase 1mM ammonium acetate-acetonitrile.
Endrin, α-endosulfan, β-endosulfan , endosulfan sulfate, heptachlor and heptachlor epoxide were determined in the negative
ionization mode, while the rest compounds in positive ionization mode. For the identification of the analytes, two multireaction
monitoring transitions were selected per compounds except for the heptachlor which selected ion monitoring was used. The linearity
of the optimized method ranges after SPE concentration, from 0.009 to 30.60 μgL−1 with correlation coefficients greater than 0.99. The method recovery values varied from 72 to 119 % for the different fortification
levels . The developed method was successfully applied to determine OCPs and their metabolites in surface water samples collected
near paddy fields in growing season of rice, at year 2005 in Pathumthani province, Thailand. Endosulfan sulfate was detected
in five out of seven samples and three of them could be quantitated in the range of 0.31to 0.50 μgL−1. 相似文献
18.
A. S. Tatikolov V. A. Kuz'min Zh. A. Krasnaya Yu. V. Smirnova 《Russian Chemical Bulletin》1999,48(7):1281-1286
The spectral and fluorescent properties of a number of cross-conjugated ketones with one or two terminalN-methylpyrrole residues and those of polyene bis-ω, ω′-dimethylamino ketones with methyl substituents in the polyene chain
and of some related compounds were studied. The photophysical properties of cross-conjugated ketones with terminalN-methylpyrrole residues are similar to those of the corresponding polyene bis-ω, ω′-dimethylamino ketones studied in detail
previously. In both series of compounds, the absorption and fluorescence spectra undergo a bathochromic shift following an
increase in the length of the polyene chains or introduction of α,α′-trimethylene or α,α′-dimethylene bridges into these chains;
the same trend is observed on passing from less polar solvents to more polar solvents (positive solvatochromism). Thermochromism
(long-wavelength shift of the absorption spectra upon cooling the solutions) is observed in both series of compounds. The
introduction of methyl substituents into the polyene chains of bis-ω,ω′-dimethylamino ketones results in a decrease in the
fluorescence quantum yield.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1293–1298, July, 1999. 相似文献
19.
A synthesis of 15-benzoyloxybutyl-20-hydroxymethylpregn-16-enes, the intermediates in the synthesis of brassino- and ecdysteroids
modified in the D ring was performed starting with 2α,3α-isopropylidenedioxy-6,6-ethylenedyoxy-5α-androst-15-ene-17-one and
its 2β,3β-isomer through a sequence of reactions involving Michael addition, Wittig reaction and ene reaction. Structures
of the compounds were proved by the methods of two-dimensional NMR spectroscopy. 相似文献
20.
Sergii Rudiuk Zoia Voitenko Sergii Riabov Alexander Roshal 《Journal of inclusion phenomena and macrocyclic chemistry》2007,57(1-4):415-417
The solubilization of 4,10-dihydrothieno[3′,2′:5,6]pyrimido[2,1-a]isoindol-4-ones by β-cyclo-dextrin by two routes––solvatofluorochromic
and extraction methods was studied. The solvatofluorochromic investigations showed that the changes occurred in the medium’s
polarity do not influence onto the fluorescent characteristics of these compounds. However, using extraction method their
solubilization by β-cyclodextrin was observed. 相似文献