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1.
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   

2.
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   

3.
The thermal behavior of Cu—Al alloys with 17, 19 and 21 at.%Al was examined by differential thermal analysis (DTA), differential scanning calorimetry (DSC), X-ray diffractometry (XRD), optical microscopy (OM) and scanning electron microscopy (SEM). The presence of the gamma phase (Al4Cu9)was clearly detected for the Cu—19 at.%Al alloy and caused the 2 phase disordering process in two stages. The tendency to increase the 2 dissolution precipitates with the increase in the Al content seems to be reverted for compositions at about 21 at.%Al and the heating/cooling ratio seems to influence the thermal response of this process. The presence of the endothermic peak corresponding to the 1 transformation depends on an incomplete decomposition reaction. The variation of the heating rate showed that the 1(+1) decomposition is the dominant reaction for alloys containing 19 and 21 at.%Al.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

4.
The structures of the products of the polyformylation of Cu, Ni, and Co complexes of etioporphyrin (EP) as monoformyl-, ,-diformyl-, ,-diformyl-, and ,,-triformyl-EP were established by electronic, IR, and PMR spectroscopy and mass spectrometry. -Formyl--(N-methylformaldimine)-EP and porphyrins that contain a cyclopentane ring can be formed by alkaline treatment of the Vilsmeier formylation products.See [1] for communication 8.See [2] for our preliminary communication.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 767–775, June, 1979.  相似文献   

5.
Summary The reduction of mesobiliverdin XIII propan-1,3-diyl diester with NaBH4 affords mesobilirubin XIII propan-1,3-diyl diester. The same reduction of mesobiliverdin XIII methylen diester. The same reduction of mesobiliverdin XIII methylen diester affords 8-(2-carboxyethyl)-3,17-diethyl-12-(3-hydroxypropyl)-2,7,13,17-tetramethylbiladien-ac-1,19-(21H, 24H)-dione (MBR-mc). The UV/Vis and1H NMR spectra ofMBR-mc show that its structure in solution is similar to that of the natural bilirubins of the series.
Zur Herstellung von Bilirubinen der natürlichen -Reihe mit Propionsäure- und Hydroxypropylsubstituenten
Zusammenfassung Reduktion von Mesobiliverdin-XIII-propan-1,3-diyl-diester mit NaBH4 liefert Mesobilirubin-XIII-propan-1,4-diyl-diester. Die analoge Reaktion des Mesobiliverdin-XIII-methylen-diesters führt zu 8-(2-Carboxyäthyl)-3,17-diäthyl-12-(3-hydroxypropyl)-2,7,13,17-tetramethylbiladien-ac-1,19-(21H,24H)-dion (MBR-mc).MBR-mc weist in Lösung (UV/Vis und 1H-NMR Spektren) eine ähnliche Struktur auf wie die der natürlichen Bilirubine der -Serie.
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6.
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   

7.
The Vilsmeier formylation of butyrolactam and of N-phenylbutyrolactam has given their -dimethylaminomethylene derivatives. The reaction of the latter with -substituted arylhydrazines leads to the formation of 1-oxo-1,2,3,4-tetrahydro--carbolines. When unsubstituted phenylhydrazine is used, the occurrence of a competing reaction leading to -aminoethyl derivatives of 5-pyrazolone is also possible. It has been established that the direction of the reaction and the ratio of the products are affected by the substituent at the lactam nitrogen atom.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 56–60, January 1984.  相似文献   

8.
The analysis of odour components in East Indian Sandalwood Oil (Santalum album L.) and in Patchouli Oil (Pogostemon cablin Benth.) based on GC-, GC-FTIR- and GC-MS-data resulted in the identification of-santalene,-santalal,-santalal, epi--santalal,-santalol,-santalol, (E)--santalol,-bergamotol and spirosantalol in Sandalwood Oil and of (–)-patchoulol,-guaiene,-patchoulene, seychellene,-bulnesene, norpatchoulenol and pogostol in Patchouli Oil as the most intense aroma compounds of these oils.  相似文献   

9.
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   

10.
Conclusions When heated in the presence of a catalytic amount of BF3 etherate,-trifluoromethyl--diethylamino--fluoroacrylic acid N, N-dimethylamide is reversibly isomerized to-trifluoromethyl--dimethylamino--fluoroacrylic acid N, N-diethylamide. The methyl esters of-trifluoromethyl--diethylammo--fluoroacrylic acid and-trifluoromethyl--phenoxy--fluoroacrylic acid N,N-dimethylamide are not isomerized under the same conditions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No.1, pp.137–141, January, 1976.  相似文献   

11.
From the far-eastern starfishHenricia sp. we have isolated and characterized the new polyhydroxysteroid (24S)-5-cholestane-3,4,6,8,15,24-hexaol and three new glycosides: (24S)-5-cholestane-3,4,6,8,15,24-hexaol 3-O-(2,4-di-O-methyl--D-xylopyranoside) (henricioside H1), 24-methyl-5-cholesta-4,22E-diene-3,6,8,15,16,26-hexaol 3-O-(2,3-di-O-methyl--D-xylopyranoside) (henricioside H2), and the 22,23-dihydro derivative of henricioside H2 (henricioside H3).Pacific Ocean Institute of Bioorganic Chemistry, Far-Eastern Scientific Center, Russian Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 249–253, March–April, 1993.  相似文献   

12.
Cyclosiversigenin 6-O--L-rhamnopyranoside and 6-O--D-glucopyranoside were isolated fromAstragalus coluteocarpusBoiss. (Leguminosae) andAstragalus dissectusB. Fedtsch. et N. Ivanova, respectively. Cyclosiversigenin 5-O--L-rhamnopyranoside was shown to be an artifact forAstragalus coluteocarpus.Thus, the cyclosiversigenin 6-O--D-glucopyranoside that was isolated from certainAstragalusspecies is hypothesized also to be an artifact. Glycosylation of the 6 -hydroxyl group of cycloartanes by D-glucose and D-xylose, in contrast with other substituents, does not change the low-field position of the PMR signal of the 4-CH 3 group (1.65 2.01 ppm) that is caused by the influence of deuteropyridine directly on the 6 -hydroxyl. Obviously one of the hydroxyls of the -D-glucopyranoside or -D-xylopyranoside residues has the same effect in this instance.  相似文献   

13.
The interaction of the cobalt phosphine complexes Co(N2)(PPh3)3, HCo(N2)(PPh3)3 and H3Co(PPh3)3 with styrene yields mono and dinuclear complexes identified by the ESR method. A paramagnetic complex, Co(PPh3) (styrene)2, is one of the intermediates in the catalytic hydrogenation of styrene.
Co(N2)(PPh3)3, HCo(N2)(PPh3)3 H3Co(PPh3)3 . , Co(PPh3) ()2.
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14.
Conclusions A study has been made of the gas-phase decomposition of eight-polynitroalkyl Sulfides and-polynitroalkyl sulfones. Decomposition parameters have been estimated and a mechanism involving rupture of the C-NO2 bond has been established. Substitution of a S atom in the position to the NO2 group lowers the C-NO2 bond energy by R10 kcal/mole.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 310–312, February, 1977.  相似文献   

15.
Summary In preparations of biliverdin-IX-dimethyl ester (2 b) from bilirubin-IX (1) the ratio of the XIII- and III-isomers3 b and4 b, formed via intermolecular scrambling, should be unity. However, irrespective of the synthetic variant considered, the amount of4 b obtained usually is exceptionally low. This is partly ascribed to a consecutive reaction of4 b in acidic methanol affording the chiral diastereomeric bridged biliverdins5 (a undb) and6 (a andb), respectively.
Zum Verbleib des durch Scrambling gebildeten Biliverdin-III-dimethylethers bei Synthesen des IX-Isomeren aus Bilirubin
Zusammenfassung Bei der Darstellung von Biliverdin-IX-dimethylester (2 b) aus Bilirubin-IX (1) sollte das Verhältnis der durch intermolekulares Scrambling gebildeten XIII- und III-Isomeren3 b bzw.4 b eins betragen. Tatsächlich aber ist die Ausbeute an4 b, unabhängig von der verwendeten synthetischen Variante, immer sehr klein. Dieser Umstand läßt sich zumindest teilweise auf eine spezifische Reaktion von4 b in saurem Methanol zurückführen, in deren Verlauf die chiralen diastereoisomeren überbrückten Biliverdine5 (a undb) sowie6 (a undb) gebildet werden.
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16.
The nucleation mechanism, kinetics and induction periods in strontium tungstate crystallization from sodium tungstate melt in platinum crucibles were investigated by differential thermal analysis. Heterogeneous nuclei first formed on the metal platinate particles within the solution during the induction periods (¯t); the main crystal growth started only after ¯t and few new nuclei were then formed. At any crystallization temperature, ¯t varied inversely with the cooling rate (R T), and with the rate (RC) of development of excess solute concentration according to the relation ¯t = 1/(k 1 R c ), wherek 1 and are constants. The critical temperature (¯T), critical supersaturation(¯ S), k 1 and were evaluated.
Zusammenfassung Der Keimbildungsmechanismus, sowie die Kinetik und die Induktionsperioden wurden bei der Kristallisation von Strontiumwolframat aus Natriumwolframatschmelzen in Platintiegeln durch Differentialthermoanalyse untersucht. Die heterogenen Kristallkeime wurden zuerst während der Induktionsperiode () an den Metallplatinat-Teilchen in der Lösung gebildet: das Hauptkristallwachstum begann erst nach und nachfolgend wurden einige neue Keime gebildet. Bei jeder Kristallisationstemperatur änderte sich umgekehrt proportional zu den Abkühlungsgeschwindigkeiten (R T) und den Geschwindigkeiten (R c) der Bildung überschüssig gelösten Materials, entsprechend der Gleichung = 1/(k 1 R c , wobeik 1 und Konstanten sind. Die kritische Temperatur (¯T), die kritische Übersättigung (¯S),k 1 und wurden bewertet.

Résumé On a étudié par analyse thermique différentielle le mécanisme de nucléation ainsi que la cinétique et les périodes d'induction de la cristallisation du tungstate de strontium, à partir des bains fondus de tungstate de sodium, dans des creusets de platine. Des noyaux hétérogènes se forment d'abord sur les particules de platinate métallique dans la solution, au cours des périodes d'induction (): la croissance principale des cristaux ne commence qu'après et il se forme alors quelques noyaux nouveaux. A une température quelconque de cristallisation, varie de façon inverse avec les vitesses de refroidissement (R T) et les vitesses de développement (R c ) de concentrations de sursaturation de la substance en solution, selon la relation = 1/(k 1 R c , oùk 1 et sont des constantes. On a évalué la température critique (¯T), la sursaturation critiques (¯S),k 1 et.

, . - (¯ t). ¯t . - ,¯t (R T), (R c) ¯t=1/(K1 R c ), 1 — . (¯), (_-S), K1 .
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17.
An unusual electrophilic cyclization of fluorine-containing carbonyl compounds and -oxides was discovered. Upon the action of SbF5, perfluorinated ketones, diketones, and -oxides isomerize to oxolanes. This reaction proceeds with the obligatory participation of the terminal CF3 group.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2611–2618, November, 1991.  相似文献   

18.
The reaction of alkoxy bromides with N1-(-tetrahydrofuryl) derivatives of pyrimidine bases has given a series of 6-alkoxy-5-bromo-1-(-tetrahydrofuryl)-5, 6-dihydrouracils. The hydrogenation of the 1-(-tetrahydrofuryl) derivatives of uracil and of 5-fluorouracil has been studied. It has been shown that in both cases 1-(-tetrahydrofuryl)-5, 6-dihydrouracil is formed.  相似文献   

19.
Zusammenfassung Die Synthese von 3, 16-Diacetoxy-5 -pregnan-20-on (VI) aus 3-Acetoxy-5 -pregn-16-en-20-on und eine verbesserte Darstellung von 3, 16-Diacetoxy-5 -pregnan-20-on (III) aus 3-Acetoxy-pregna-5, 16-dien-20-on werden beschrieben.  相似文献   

20.
A study has been made of temperature programmed desorption (TPD) of NH3 and H2O from samples of NH4X and CoNH4X zeolites of various degree of exchange. NH3 TPD peaks could be explained by interaction of NH3 with different Brönsted and Lewis acidic centers. Moreover a water peak at high temperatures allowed interpretations of the dehydroxylation, and by reason of the characteristic desorption temperatures a particular state of the Co2+ ions in the CoNH4X zeolites is postulated.
- () NH3 H2O NH4X CoNH4X . NH3 NH3 =qs . . Co2+ CoNH4X.
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