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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.
The isomerization of the hetaryl analogs of unsymmetrical benzoins on heating in basic media is a convenient preparative method for the production of -hydroxyacyl derivatives of -excessive heterocycles. The motivating force here for the isomerization is the formation of a thermodynamically more stable product. It was established that isomerization is promoted by increase in the difference between the electron-donating characteristics of the (het)aryl residues  相似文献   

3.
Conclusions Some,-bisdialkylphosphonoisopropylnitroxyl radicals were obtained by the thermolysis of dialkyl -nitrosoisopropylphosphonates and isolated in the pure state.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1867–1868, August, 1979.  相似文献   

4.
A general differential method is developed and described which determines the Arrhenius parameters, energy of activation and the preexponential factor, as functions of degree of conversion from sets of two or more experiments with differing thermal programs. (These experiments may be performed at any combination of isothermal, constant heating rate or other temperature programs.) The method tests to see whether or not the kinetics follow the equation,f()=(1–)n, and calculates the correct reaction order, n, when such an equation is applicable. The correct energy of activation,E, is determined as a function of both temperature and conversion. The correct preexponential term,A, is calculated for all cases described by equation, d()/dt=f () A exp(–E/RT), except for the autocatalytic case in whichf()=0)=0. Calculation of parameters for equations involving other functions forf() will be described in a subsequent paper.
Zusammenfassung Es wurde ein allgemeines Differentialverfahren entwickelt und beschrieben, das die Arrheniusschen Parameter, namentlich die Aktivierungsenergie und den präexponentiellen Faktor, als Funktion des Umsetzungsgrades aus Angaben über zwei oder mehrere Experimente mit verschiedenen Temperaturprogrammen beschreibt. (Diese Experimente können mit beliebigen Kombinationen aus isothermen Temperaturprogrammen, solchen mit konstanter Aufheizgeschwindigkeit oder anderen Temperaturprogrammen durchgeführt werden.) Das Verfahren überprüft, ob die Kinetik durch die Gleichungf()=(1–)n beschrieben werden kann und berechnet die richtige Reaktionsordnungn, wenn eine solche Gleichung anwendbar ist. Die richtige Aktivierungsenergie E wird als Funktion von Temperatur und Umsatz bestimmt. Der richtige präexponentielle Ausdruck wird für alle beschriebenen Fälle mittels der Gleichung d()/dt=f()A exp (-E/RT) berechnet. Eine Ausnahme bildet der Fall Autokatalyse, wobeif(=0)=0 gilt. Die Berechnung der Parameter für Gleichungen mit anderen Funktionen fürf() wird in einem späteren Manuskript beschrieben.
  相似文献   

5.
New -amino phosphonates containing different alkyl and aryl substituents at the -carbon atom were synthesized in high yields by the Kabachnik—Fields and Pudovik reactions. These compounds were studied as carriers of several -hydroxy carboxylic and dicarboxylic acids through liquid impregnated membranes. These -amino phosphonates studied are capable of molecular recognition of oxalic acid among structurally similar -hydroxy carboxylic and dicarboxylic acids. The efficiency and selectivity of mass transfer of oxalic acid increase with an increase in the lipophilicity of the -amino phosphonate.  相似文献   

6.
Summary 1. The synthesis of L-(+)--oleoyl--linoleoyl--glycerylphosphorylethanolamine has been effected.2. During the investigations the following substances were isolated and characterized: L--oleoyl--glycerylphosphoryl-N-phthaloylethanolamine and L---linoleoyl--glycerylphosphoryl-N-phthanoylethanolamine.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 2, pp. 80–83, 1966  相似文献   

7.
Summary Various methanol-based, binary and ternary solvent systems were compared with respect to resolution of cis isomers of and -carotene by reversed-phase HPLC. A ternary system: acetonitrile-methanol-methylene chloride (751510), or a binary system: acetonitrilemethanol (9010 or 595) provided the best separation of -carotene and its four cis isomers, 9-cis, 13-cis, 15-cis and 13,15-di-cis--carotene. The elution order of 9-cis and 13-cis--carotene was dependent on the methanol concentration. Methanol-methylene chloride (991) resolved -carotene and its three cis isomers, 9-cis, 13-cis, and 15-cis--carotene. It also proved the best for simultaneous separation of cis isomers of and -carotene. Sample solvent can affect the separation efficiency of each isomer. The presence of cis isomers of and -carotene in fresh and cooked carrots was also determined.  相似文献   

8.
By chromatography on Polikhrom-1, silica gel, and Florisil, an ethanolic extract of the digestive organs of the starfishPatiria pectinifera has yielded the steroid polyols 5-cholestan-3,6,8,15,16,26-hexaol and 5-cholestan-3,4,6,7,8,15,16,26-octaol 6-(sodium sulfate). The structures of the compounds have been shown by spectral characteristics and chemical transformations.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 738–741, November–December, 1984.  相似文献   

9.
Summary A comparative discussion of the signals in the13C NMR spectra of acetylated methyl - and -D-xylopyranosides, - and -D-glucopyranosides, - and -D-galactopyranosides, - and -L-arabinopyranosides, - and -L-fucopyranosides, and - and -L-rhamnopyranosides and of the corresponding free glycosides has shown a similarity of the effects of substitution at C5 with a longer-range nature of these effects in the case of the acetylated glycosides.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center of the Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 6–8, January–February, 1979.  相似文献   

10.
The calcium salts of -sulfonated fatty acid methyl esters were prepared, and the physico-chemical properties such as solubility, critical micelle concentration, aggregation number, and precipitation phase boundary were studied to clarify the reasons for the good hardness tolerance manifested by -sulfonated fatty acid methyl esters.The Krafft point of the calcium salts of -sulfonated fatty acid methyl esters were not necessarily lower than room temperature, but the rate of crystallization in hard water was extremely slow compared with the calcium salt of dodecyl sulfate, which has been known as an insufficient surfactant in terms of hardness tolerance.  相似文献   

11.
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   

12.
Crystal structure refinement was performed of the metastable modification of glycine (space gr. P21, a = 5.092(2) , b = 6.273(3) , c = 5.384(3), = 113.17(4)°, Z = 2, R = 0.0274). The crystals were obtained by a new method (not described in the literature): they were precipitated from a water solution with the addition of glacial acetic acid. The crystal structure of the glycine modification [space gr. P21/n, a =5.106(1) , b = 11.979(5) , c = 5.463(2) , = 111.75(2)°:, Z =4] was refined for comparison. Transition from the to the modification in a damp atmosphere was revealed, resulting in the formation of a strongly strained crystal of a mosaic structure. The orientation of the crystallographic axes in the newly formed crystal of the modification relative to the axes in the initial crystal of the modification was determined. It is shown that as in glycine, the lengths of the intramolecular C—O bonds in the modification are fairly similar [1.248(2) and 1.253(2) ] and the previously found significant difference between them is most likely due to the errors of the photomethod. A comparative analysis of the crystal structures of the and glycine modifications (glycine zwitterion packings and structure of intermolecular hydrogen bond networks) was performed. Data of the analysis are used to discuss the properties of the glycine modifications, the possible reasons for the stability of the modification in dry air, the difficulties of crystal growth from solutions, and the ease of crystallization of the modification under various conditions.  相似文献   

13.
We have determined the spectroscopic characteristics, the dipole moments, and the Kerr constants of the stereoisomers of the secondary-tertiary diols of the cyclohexane and bicyclo [4.1.0]pentane series: 3,4-dihydroxy-3-carane (I), 3,4-dihydroxy-3-methylnorcarane (II), 3,4-dihydroxy-3-methylnorcarane (III), 4, 5-dihydroxy-3-methylcyclohexene (IV), 3,4-dihydroxy-3-carane (V), 3,4-dihydroxy-3-methylnorcarane (VI), 3, 4-dihydroxy-3-carane (VII), and 3,4-dihydroxy-4-methyl-3-carane (VIII). It was found that the cis diols are more polar than their trans isomers. It was shown by electrical and electrooptical methods that rotamers with a gauche orientation with respect to the tertiary C-O are stable relative to those containing the diol at the ordinary C-C bond of the ring.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 619–625, March, 1991.  相似文献   

14.
Conclusions A synthesis of 6-methyl-16.17-cyclobutanopregn-4-ene-3,20-dione was carried out by opening the 5,6-oxide ring with a Grignard reagent, with preliminary protection of the 20-keto group.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2151–2154, September, 1982.  相似文献   

15.
Zusammenfassung Für die Elemente Neon, Natrium, Magnesium, Aluminium und Silizium werden mit einem quantenmechanischen Variationsverfahren unter Verwendung einer minimalen STF-Funktionenbasis Röntgenübergänge vom Typ K 1L1L2 berechnet und den K -Satellit-Linien , , 3, 3 and 4 zugeordnet.
Relation between K -Satellits and X-ray-transitions of the type K 1 L 1L 2 for Ne, Na, Mg, Al and Si
STF-Calculations are reported for X-ray-transitions of the type K 1L1L2 for Ne, Na, Mg, Al and Si. It is shown that these transitions are correlated with the K -satellits , , 3, 3 and 4.


Die Wellenfunktionen können auf Anfrage zur Verfügung gestellt werden.  相似文献   

16.
The action of N-methylpiperazine and , -dimethylpyrrolidine on chloroacetyl derivatives of phenylhydrazides of diaryl- and dialkylglycolic acids has given the previously unknown N-methylpiperazinoacetyl and , -dimethylpyrrolidnoacetyl derivatives of these phenylhydrazides.For part XL, see [1].  相似文献   

17.
Summary Depsipeptides containing -hydroxy -amino acid residues as hydroxy-acid component were synthesized.Communication 11 of the series -Substituted -Amino Acids.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 1987–1992, November 1965  相似文献   

18.
    
The previously unreported N, N-diformyl-, -bipiperidyl has been synthesized by the reaction of ,-bipiperidyl with carbon monoxide under pressure.  相似文献   

19.
Summary We have previously described a normal-phase HPLC method for the simultaneous determination of , , and tocopherol, thecis andtrans isomers of retinol, and total carotenes in different Italian cheeses and milk. In this paper we describe a reversed-phase HPLC method using solely methanol as the mobile phase for the determination of -tocopherol, -+-tocopherols, total retinols, cholesterol, -sitosterol, campesterol and stigmasterol, and - and -carotene. The method developed has been applied to some new dairy products such as natural Quark, with olive, basil or banana and to processed cheese with tomato and the results have been compared with the corresponding results obtained by the normal-phase method. The conclusion is that more complete evaluation of the tocopherol, retinol, carotene and sterol content of dairy products, especially when vegetables and fruits are present, is necessary and can be obtained using both the normal- and reversed-phase HPLC methodologies.  相似文献   

20.
Zusammenfassung Beim Versuch zur Darstellung von 4-Vinyltriarylmethylradikalen durch Umsetzung von 4-Vinyltriarylmethylchloriden mit Metallen entstehen intermediär Radikale, die jedoch sofort in einer mesomeren Form weiterreagieren, wobei Polymere mit Chinodimethan-Strukturen entstehen. Als Modell hierfür dient das gelbe 1,4-,-Diphenylchinodimethan, das aus 4-Methyltriphenylmethylchlorid und Pyridin in Lösung erhalten werden kann; es ist nicht in fester Form isolierbar und polymerisiert sich leicht zu Poly-1,4-,-diphenylxylylen, das durch IR- und NMR-Spektren identifiziert wird.
The attempted preparation of 4- vinyltriarylmethyl radicals
The attempted preparation of 4-vinyltriarylmethyl radicals by interaction of 4-vinyltriarylmethylchlorides with metals yielded unstable radical intermediates immediately undergoing further reaction to give polymers of a quinodimethane structuretype. 1,4-,-Diphenylquinodimethane, obtained from 4-methyltriphenylmethyl chloride and pyridine in solution, was used as a model compound. It cannot be isolated and readily polymerizes to give poly-1,4-,-diphenylxylylene identified by IR and NMR spectra.


Mit 2 Abbildungen  相似文献   

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