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 359 毫秒
1.
Five new sulfated derivatives of sokotrasterol and halistanol have been obtained: 24-nor-5-cholane-2,3,6,23-tetraol 2,3,6-tri(sodium sulfate); 24-nor-5-cholane-2,3,6,23-tetraol 2,3,6-tri(sodium sulfate) 23-palmitate; 24,25-dimethyl-5-cholestane-2,3,6-triol 3-(sodium sulfate); 24,25-dimethyl-5-cholestane-2,3,6-triol 6-(sodium sulfate); and 24,25-dimethyl-5-cholestane-2,3,6-triol 2,6-di(sodium sulfate). The inhibiting and membranolytic properties of the polysulfated steroids from sponges and their derivatives have been studied. It has been shown that physiological activity in this series of compounds depends on biphilicity.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 441–445, July–August, 1986.  相似文献   

2.
Circulardichroismspectra of 5- and 7-bromo-6-ketosteroidsof the cholestane and stigmastane serieswere studied. A negative Cotton effect corresponding to the n-* -transition of the ketone was observed in the CD spectra of 5-bromo-6-ketosteroids at 300 nm. The analogous Cotton effect was positive in CD spectra of 7-bromo-6-ketosteroids.  相似文献   

3.
The synthesis of the 17(20)-16 analog of natural chiogralactone is described. Attempts to introduce a 6-oxo group directly into the -lactone proved unsuccessful, since the first stage — saponification — took place with the formation of three products: the 3-hydroxy--lactone, the 3-hydroxy-20(22)-lactone, and the 15,17(20)-dienoic acid. The synthesis of the desired compound was effected from the ethyl ester of the 5,16-dienoic acid by the scheme 3-acetate3-tosylate6-hydroxy-3,5-cyclosteroid6-oxo-3,5-cyclosteroid6-oxo-5H--lactone. It has been shown that the cyclopropane ring in the 3,5-cyclosteroid -lactone is extremely stable under the conditions of acid treatments.N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 184–187, March–April, 1981.  相似文献   

4.
A study of the extraction of polonium from aqueous solutions containing -hydroxyisobutyric acid (-HIBA) was performed with four different extractants, di-n-octyl sulphide (DOS), Cyanex 272, Cyanex 301 and Cyanex 302, dissolved in toluene. The extracted complex for DOS at low -HIBA concentrations is most likely PoO(-HIB)2·2DOS, while at higher -HIBA concentrations there seems to be a solvating effect implicating an extracted complex of the type PoO(-HIB)2(-HIBA)2·2DOS. For the extraction of polonium with Cyanex 272 the results are inconclusive. The extracted complex is either PoOA2 or PoO(-HIB)2·2HA. For extraction with Cyanex 301 or Cyanex 302 the major extracted species does not contain any -HIBA molecules. The neutral species in both cases is PoOA2, extracted at low extractant concentrations, while at higher extractant concentrations a complex of the type PoOA2·xHA is extracted. The extraction of polonium increases in the order Cyanex 272 < DOS < Cyanex 302 < Cyanex 301.  相似文献   

5.
Zusammenfassung Aus den entsprechenden -Bromestern werden durch Umsetzung mit Natriumnitrit die -Oximinodicarbonsäuredimethylester C7 und C9 und der , -Dioximinoazelainsäuredimethylester erhalten. -Methyladipinsäure wird zum Gemisch aus -Bromund -Bromester umgesetzt. Mit Natriumnitrit wird -Nitro-und -Oximino--methyladipinsäuredimethylester erhalten.
The -oximino dicarboxylic dimethyl esters of C7 and C9 and the , -dioximino azelaic acid dimethyl ester are received from the corresponding -bromo esters by reaction with sodium nitrite. -Methyladipic acid is reacted with bromine to a mixture of the -bromo and -bromo ester. Reaction with sodium nitrite gives the -nitro ester and the -oximino ester of -methyl adipic acid.


5. Mitt.:H. Reinheckel, Mh. Chem.98, 1217 (1967).  相似文献   

6.
New coumarin glycosides — haploperosides C, D, and E — have been isolated from the epigeal part of theHaplophyllum performatum (MB) Kar et Kir. On the basis of chemical transformations and spectral characteristics, haploperoside D has the structure of 6-methoxy-7-[0--L-rhamnopyranosyl-(1 2)--D-glucopyranosyloxy]-2H-benzopyran-2-one, and haploperoside C that of 6-methoxy-7-[0--L-rhamnopyranosyl-(1 6)-(2-0-acetyl--D-glucopyranosyloxy)]-2H-benzopyran-2-one. The structure of haploperoside E has been established as 7-[0--L-rhamnopyranosyl-(1 2)-0--L-rhamnopyranosyl-(1 6)--D-glucopyranosyloxy]-2H-benzopyran-2-one. The structures of haploperosides A and B have been refined. An assignment has been made of the carbon signals in the13C NMR spectra of haploperosides A, D, C, and E.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 27–35, January–February, 1985.  相似文献   

7.
The effect of representing dielectric properties in terms of the complex polarizability c = – i is examined. Loss curves ( and tan ) are shifted towards higher frequencies, revealing the existence of new relaxations and allowing the clarifications of ones already known. We have calculated the shift ratios (at maximum or tan )/ (at maximum or tan ) from the more conventional empirical equations representing the dielectric behavior. Some examples are given.  相似文献   

8.
On electrolysis mono- and bicyclic furfuryl-substituted alcohols undergo intramolecular alkoxylation, giving polycyclic spirans. Spiro[perhydrobenzofuran-2, 2-(5-methoxy, 5H)furan] and spiro[4H, 5H, 6H, 11H-naphtho-(,)-furan-2(3H)] [2-(5-methoxy, 5H)furan], hitherto not described, are prepared in this way. On catalytic hydrogenation they give the previously unknown spiro[perhydrobenzofuran-2, 2-tetrahydrofuran] and spiro[4H, 5H, 6H, 11H-naphtho-(,)-furan-2(3H)][2-tetrahydrofuran].For Part XXIX see [1].  相似文献   

9.
A study is made of the reaction of the sodium and ammonium salts of 1 -alkyl- and 1, 2-dialkyl-4-nitro-5 mercaptoimidazoles with -halogenoketones, -halogenoalcohols, and — and -halogeno acids, to give a number of 1 -alkyl- and 1, 2-dialkyl-4-nitro-5- [-ketoalkyl (aralkyl)-, -hydroxyethyl-, and -and -carboxyalkyl] mercaptoimidazoles.For Part XXIV see [6].  相似文献   

10.
Conclusions Two independent methods were found for the preparation of pregn-5-en-3,21-diol-[16,-17-d]-2'-methyloxazoline: 1) by cis-opening of the aziridine ring of the 3;16,17;21-triacetate of 16,17-epiminopregn-5-en-3,21-diol-20-one and 2) by the 21-hydroxylation of pregn-5-en-3-o1-20-one-[16,17-d]-2'-methyloxazoline using iodosobenzoyl diacetate.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2138–2141, September, 1984.  相似文献   

11.
The selectivity of competitive hydrogenation of 2-methyl-3-butene-2-ol and 1-hexene on 5% Pt on silica gel catalyst at 20°C and atmospheric pressure was investigated, and the effect of changes in the composition of the solvent on the selectivity of hydrogenation was examined. Three solvent systems have been used: methanol-water, 1-heptanol-cyclohexane and ethanol-cyclohexane mixtures. The causes underlying changes in the selectivity of hydrogenation with changing composition of the solvent are discussed.
2--3--2- 1- 5% Pt 20°C . . 1- . .
  相似文献   

12.
Triterpene glycosides from Pulsatilla chinensis   总被引:1,自引:0,他引:1  
Four triterpene glycosides were isolated from the roots of Pulsatilla chinensis (Bunge) Regel (Ranunculaceae). Two new glycosides, chinensiosides A (1a) and B (2), were identified as 3-O-[-L-rhamnopyranosyl-(12)--L-arabinopyranosyl]-28-O-[-L-rhamnopyranosyl-(14)--D-glucopyranosyl-(16)--D-glucopyranosyl]-3,23-dihydroxylup-20(29)-en-28-oic acid and 3-O-{-L-rhamnopyranosyl-(12)-[-D-glucopyranosyl-(14)]--L-arabinopyranosyl}-28-O-[-L-rhamnopyranosyl-(14)--D-glucopyranosyl-(16)--D-glucopyranosyl]-3,23-dihydroxylup-20(29)-en-28-oic acid. The other two glycosides were identified as previously known hederasaponin C (3) from Hedera helix and glycoside III (4) from Pulsatilla cernua.  相似文献   

13.
Steroids     
Summary 1. A new type of steroido[17, 16-d]-3-(methyl, phenyl)isoxazoles has been synthesized by the cyclization of the syn-oximes of acylated 3-hydroxy-16, 17-oxidopregn-5-en-20-ones or their 5-saturated derivatives and acylated 17-benzoyl-3-hydroxy-16, 17-oxidoandrost-5-ones.2. It has been established that the Beckmann rearrangement of the anti-oximes of acylated 17-benzoyl-3-hydroxy-16, 17-androst-5-enes leads to a mixture of anilides and steroidoisoxazoles, which shows the inversion of the configuration of the oximes (from the anti to the syn form) during the rearrangement.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 5, pp. 325–333, 1966  相似文献   

14.
Zusammenfassung Auf übliche Art wurden folgende Verbindungen hergestellt: -Naphtylhydrazono-cyanacetylcarbamidsäureäthylester (1 a), 1-(-Naphthyl)-5-cyano-6-azauracil (2 a), 1-(-Naphthyl)-6-azauracil-5-carbonsäure (3 a), 1-(-Naphthyl)-6-azauracil (4 a), Amidoxim der 1-(-Naphthyl)-6-azauracil-5-carbonsäure (5 a), 1-(-Naphthyl)-5-[5-methyl-1,2,4-oxdiazolyl(3)]-6-azauracil (6 a) und die entsprechenden -Isomere aller dieser Verbindungen (1 b–6 b).5. Mitt.:J. Slouka, Mh. Chem.97, 448 (1966).  相似文献   

15.
Zusammenfassung Es wird die quantitative Bestimmung der 5 Amine rac-N,N-Dibutyl-,-diphenyläthylendiamin (A), meso-N,N-Dibutyl-,-diphenyläthylendiamin (B), 1-Phenyl-1-butylamino-2-methyl-propan (C), N-Butyl-benzylamin (D) und Butylamin (E) in Reaktionsgemischen durch 54- und 95 stufige Craig-Nach-fraktionierungsprozesse in einer Verteilungsbatterie mit 35 Elementen nach Hecker [1] beschrieben. Durch graphische Auswertung der überlappenden Verteilungskurven wird eine quantitative Bestimmung auch bei 54 stufigen Prozessen, d.h. bei unvollständiger Trennung möglich.
Quantitative determination of amine mixtures by multiplicative distributionOn the separation of organic bases by Craig distribution. IX
The quantitative evaluation of the 5 amines, rac-N,N-dibutyl-,-diphenylethylenediamine (A), meso-N,N-dibutyl-,-diphenylethylenediamine (B), 1-phenyl-1-butylamino-2-methyl-propane (C), N-butyl-benzylamine (D) and butylamine (E) in reaction mixtures by Craig after-fractionation processes of 54 and 95 steps in a distribution machine with 35 elements by Hecker [1] is described. By graphic evaluation of the overlapping distribution curves a quantitative determination is achieved, even with processes of 54 steps, i. e. incomplete separation.


8.Mitteilung: Sohönenberger, H., Eder, M.: diese Z. 249, 117–120 (1970).

Wir danken der Deutschen Forschungsgemeinschaft und dem Fonds der Chemischen Industrie für die Förderung unserer Untersuchungen.  相似文献   

16.
A new method was developed for the synthesis of -alkyl- and ,-dialkyl--phenyltryptamines based on alkylation of nitroalkanes with -phenyl-nor-gramine.  相似文献   

17.
summary The reaction of telomerization of ethylene with carbon tetrachloride or chloroform is initiated by hexacarbonyls of chromium, molybdenum, and tungsten at 115–120, forming ,,,-tetrachloroalkanes and ,,-trichloroalkanes. respectively.  相似文献   

18.
To improve the activity and the cell specificity of gene transferof polyamidoamine starburst dendrimer, we prepared -CyD conjugates with mannosylateddendrimers (generation 2 (G2), man--CDE conjugates) having various degrees of substitution(DS) of mannose residue. The man--CDE conjugates (DS 1, 3 and 5) formed complexeswith plasmid DNA (pDNA), but man--CDE conjugate (DS 8) did not. The gene transferactivity of man--CDE conjugates (DS 1, 3 and 5) and -CDE conjugate was augmented with an increasein the charge ratio of vector/pDNA, without showing cytotoxicity. Man--CDE conjugates(DS 3 and 5) showed higher gene transfer activity than -CDE conjugate in A549 cells, whichrecognize mannose, but man--CDE conjugates (DS 1 and 8) showed almost comparable gene transfer activityto -CDE conjugate (G2). On the other hand, no appreciable enhancing effect of man--CDEconjugates (DS 3 and 5) on the transfer activity was observed in NIH3T3 cells, which do not recognizemannose. These findings suggest that man--CDE conjugates (DS 3 and 5) can be new preferablecell-specific non-viral vectors of pDNA to cells which recognize the mannose moiety.  相似文献   

19.
Two new glycosides, gomphotin (1) and gomphotoxin (13), and also the known gomphoside (9) have been isolated from the leaves ofGomophocarpus fruticosus. Compounds (1) and (9) contain a 4,6-dideoxyhexosulose residue as the sugar component, and (13) a 6-deoxyhexosulose, which are attached to glycolic OH groups of the aglycons by 3-O-1,2-O-2 (9, 13) and 3-O-1,4-O-2 (1) acetal-ketal bonds. The structures of the new compounds are represented by the names (3-O-1,4-O-2)-(2,3-dihydroxy-4, 6dideoxyhexulosido)-14-hydroxy-5-card-20(22)-enolide* (1) and (3-O-1,2-O-2)-(2,3,4-trihydroxy-6-deoxyhexulosido)-14-hydroxy-5-card-20(22)-enolide* (13).State Scientific Center for Drugs of the Ministry of Health and the National Academy of Sciences of the Ukraine, Kharkov, fax 441118. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 824–832, November–December, 1995. Original article submitted May 22, 1995.  相似文献   

20.
In a continuation of the research on use of 20-keto-16,17-epoxysteroid 20-hydrazones for synthesis of 17-thio analogs of 20-ketosteroid 16,17-acetonides [2, 3], we synthesized 5-H-pregnane-3,16,21-trihydroxy-17-thiol-20-one 16,17-acetonide and found methods for its microbiological dehydrogenation and hydroxylation into 4-3-keto-and 9-hydroxy-4-3-keto derivatives.See [1] for Communication 188.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 5, pp. 1182–1186, May, 1992.  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