Steroid compounds from the starfish Lysastrosoma anthosticta collected in the Sea of Japan

Six polyhydroxylated steroids and their derivatives were isolated from the starfish Lysastrosoma anthosticta collected in the Posyet Bay, Sea of Japan. These include a new glycoside of the steroid polyol, lysastroside A (1), which was identified as (25S)-26-O--d-xylopyranosyl-5-cholestane-3,6,8,15,16,26-hexaol, and the previously known pycnopodioside C monoglycoside (2), marthasterone sulfate (3), (25S)-5-cholestane-3,6,8,15,16,26-hexaol (4), (25S)-5-cholestane-3,6,7,8,15,16,26-heptaol (5), and (25S)-5-cholestane-3,6,7,8,15,16,26-heptaol (6). The compounds were tested for the haemolytic activity and the action on the embryogenesis of the sea urchin Strongylocentrotus intermedius.     

Non-Aqueous Capillary Electrophoresis with Indirect Photometric Detection for Direct Analysis of Pb2+, Zn2+ and Cd2+ Ions

A new approach, based on non-aqueous capillary electrophoresis separation and indirect photometric detection, was established for the determination of the transition metal ions Pb²⁺, Zn²⁺ and Cd²⁺. Under optimized conditions, the method produced baseline separation of these three metal ions. The linear range and detection limits were 1050µM, 1.9µM for Cd²⁺; 1050µM, 2.1µM for Zn²⁺; and 20100µM, 3.8µM for Pb²⁺, respectively.     

Triterpene Glycosides of Tetrapanax papyriferum. II. Isolation and Structure Determination of Glycosides St-E2, St-F2, St-J2, and St-K2 from Stem Bark

Stem bark ofTetrapanaxpapyriferum yielded the new triterpene glycosides 3-O-[-D-glucopyranosyl-(13)]--D-galactopyranosyl-(12)-O--L-arabinopyranosides of oleanolic and echinocystic acids and their 28-O--L-rhamnopyranosyl-(14)-O--D-glucopyranosyl-(16)-O--D-glucopyranosyl esters. Their structures were established using chemical and physicochemical methods     

High-temperature reduction of SO2 by methane at various CH4/SO2 ratios

The character of the effect of initial reaction mixture and temperature on the selectivity of catalytic reduction of sulfur dioxide by methane in the presence of oxygen has been studied.

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.

     

ESR studies of T3+ complexes formed in the catalytic system TiCl2(acac)1+Et2AlCl and their interaction with ethylene, carbon monoxide and pyridine

Coordination state of Ti³⁺ions formed in the homogeneous catalytic systems TiCl₂(acac)₂+Et₂AlCl, and its changes upon interaction with ethylene, carbon monoxide and pyridine have been studied by ESR.

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Ti³⁺, TiCl₂(acac)₂=Et₂AlCl, , .

     

Effect of reduction temperature on the dehydrocyclizing activity of pure chromia and chromia containing K2O and CaO

The dehydrocyclization of n-heptane at 520–550°C over pure chromia and chromia with added CaO and K₂O (5 wt.% each) has been investigated. Introduction of an alkaline additive into Cr₂O₃ decreases markedly the yield of toluene. Raising of the reduction temperature of alkali-containing samples from 550 to 700°C results, in contrast to pure Cr₂O₃ and chromia-alumina systems, not in diminished, but in increased yields of toluene, the activity enhancement being particularly pronounced for the CaO-containing catalyst. These increased activities cannot be correlated either with variations in specific surface area or changes in the content of Cr⁶⁺ during subsequent oxidation, and presumably should be ascribed to more extensive catalyst reduction at higher temperatures.

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- 520–550° CaO K₂O ( 5% .). Cr₂O₃ . 550° 700° , Cr₂O₃ , , , CaO. , , .

     

Marked differences between acetonitrile/water and methanol/water mobile phase systems on the thermodynamic behavior of benzodiazepines in reversed phase liquid chromatography

Summary Two different methods were used to determine the separation factor at different temperatures and the Gibbs-Helmholtz parameters ((H), (S)) of two adjacent benzodiazepines on a chromatogram were obtained from plots of ln versus 1/T. We first studied each factor (fraction of water in the ACN/water mixture and column temperatureT), which controls the retention mechanism, and then we examined the simultaneous variation of all these factors. The changes in (H) and (S) in relation to a volume fraction of water in an ACN/water mixture were examined. In the ACN/water system, (H) was fairly constant in the acetonitrile region of 0.52 and appears to be a roughly linear function of for 0.52. In this system (S) is approximately a parabolic function of with an optimum at 0.52. The retention mechanism of ten benzodiazepines was found to be significantly different in the methanol/water and ACN/water mixtures. The separation optimization of these ten benzodiazepines was then considered. A fraction of water of 0.43 in the ACN/water mixture and a column temperature of 44°C gave the most efficient separation conditions in the ACN/water mixture.     

Phase diagram for the Tl2Te-Bi2Te3 system

The phase equilibria in the Tl₂Te-Bi₂Te₃ system were studied by means of cooling curve determination, differential thermal analysis and X-ray diffraction methods; the results obtained with the former two methods were compared. The phase diagram established for the system differed considerably from three others published previously.

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Zusammenfassung Mittels Differentialthermoanalyse, der Bestimmung der Abkühlungskurven und röntgendiffraktionsaufnahmen wurde das Phasengleichgewicht des Systemes Tl₂Te-Bi₂Te₃ untersucht. Die Ergebnisse ersterer beider Methoden wurden miteinander verglichen. Das für das System entwickelte Phasendiagramm weicht erheblich von drei vorangehend veröffentlichten Phasendiagrammen ab.

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, l₂T-³ ₂₃. . .

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The present work was financed by the Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wrocaw, from grant CPBP 01.12.     

Kinetics and mechanism of thermal decomposition of cadmium(II) complexes with substituted thioureas

From the thermal decomposition curves of cadmium(II) complexes with substituted thioureas (methyl-, dimethyl-, ethyl-, diethyl-, butyl-, dibutyl-, phenyl-, diphenyl-, acetyl- and benzoylphenylthiourea), the kinetic parameters of the thermal decompositions of these complexes were determined and a decomposition mechanism was suggested. The following thermal stability sequence is given for the Cd(II) complexes: complexes with alkylthioureas < complexes with phenylthioureas < complexes with acylthioureas.

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Zusammenfassung Die kinetischen Parameter der thermischen Zersetzung von Verbindungen der Formeln Cd(MeTM)₄(ClO₄)₂, Cd(DMeTM)₄(ClO₄)₂, Cd(EtTM)₄(ClO₄)₂, Cd(DEtTM)₄(ClO₄)₂, Cd(BuTM)₄(CtO₄)₂, Cd(DBuTM)₄(ClO₄)₂, Cd(AcTM)₃(ClO₄)₄, Cd(FTM)₄(ClO₄)₂ und Cd(DFTM)₄(ClO₄)₂ wurden mittels TG and DTG untersucht. Die Reaktionsordnung (n) und die Aktivierungsenergie (E _a) wurden nach der graphischen Methode ermittelt.

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(- , - , - , - , - -l- ), . : < < .

     

XPS studies of γ-Al2O3-supported sulfide catalysts

A marked (0.4–0.8 eV) increase in binding energy (BE) of M 2p_3/2 has been found for (M, Mo)/Al₂O₃ (M=Ni, Co) sulfide catalysts prepared by anchoring metal complex precursors and using an impregnation technique, compared to highly dispersed M/Al₂O₃ sulfides. This effect is ascribed to the decrease in the electron density on M atoms due to the formation of a sulfide bimetallic species (SBMS).

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(M, Mo)/Al₂O₃ (M=Ni, Co), , , (0,4–0,8 ) E_CB M 2p_3/2 M/Al₂O₃. ().

     

Kinetic regularities for the interaction of anion-radicals O2? with benzene and toluene on Mo?Mg oxide systems

Interaction of anion-radicals O ₂ ^– with adsorbed forms of benzene and toluene at 293–473 K is shown to be described by an equation corresponding to exponential activation energy distribution of O ₂ ^– . It has been established that under the same conditions the decay rate of O ₂ ^– is higher in the presence of toluene than with benzene.

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, - O ₂ ^– 293–473 , O ₂ ^– . , O ₂ ^– , .

     

Kristalldaten und thermische Zersetzung der Modifikationen des Kaliumhydrogenjodats,KH(IO3)2

Zusammenfassung Die Kristalldaten der- und der-Modifikation des KH(JO₃)₂ wurden bestimmt; die von früheren Autoren angegebene rhombische-Modifikation konnte nicht aufgefunden werden. Bei der thermischen Zersetzung ergeben beide Kristallarten zunächst Wasser, dann I₂O₅ und O₂; es bleibt KI zurück. Als Zwischenstufe entsteht K₂I₄O₁₁. Die Temperaturen der DTA- und DTG-Spitzen zeigen bei der- und der-Modifikation sicher nachweisbare Unterschiede.

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The crystal data of the- and-modifications of KH(IO₃)₂ were determined. The rhombic-modification which has been described by earlier authors could not be obtained. In the course of thermal decomposition both crystal types release water, then I₂O₅ and O₂, leaving a residue of KI. As an intermediate, K₂I₄O₁₁ is formed. The temperatures of the DTA and DTG peaks of the- and-modifications, were found to be different.

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Résumé On a déterminé les données cristallographiques des modifications et de KH(IO₃)₂. On n'a pas pu retrouver la modification mentionnée par d'autres auteurs dans des travaux plus anciens. Lors de la décomposition thermique, les deux modifications cristallographiques perdent d'abord de l'eau, puis I₂O₅ et O₂; le résidu est constitué par KI. On décèle K₂I₄O₁₁ comme intermédiaire. Les températures des pics ATD et TGD des deux modifications montrent des différences marquées.

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- (IO₃)₂.- , . , I_{25 2}, KI. ₂I₄₁₁. - , , .

     

The Effect of cis-trans Isomerism on the Electronic-vibrational Structure of the Ground and Excited States and Reactivity of 2-(2-Furyl)- and 2-(2-Thienyl)oxazole

The fluorescent properties, structure, and electronic structure of the ground and excited singlet and triplet electronic states of the cis and trans forms of 4,5-dihydro-2-(2-furyl)oxazole, 4,4-dihydro-2-(2-thienyl)oxazole, 2-(2-furyl)oxazole (FO), and 2-(2-thienyl)oxazole (TO) have been studied. The orbital nature of the lower excited singlet and triplet states has been studied by the semiempirical INDO/S (valence approximation) and PPP/S ( approximation) methods. It was shown that for FO and TO molecules the lower triplet state is of the * type, for which delocalization of the electronic excitation on atoms is characteristic. In the singlet excitation state inversion was observed of the energy levels of the delocalized * states and n* states localized over several bonds (for the free TO and FO molecules the lower excited singlet states S₁* were assigned to * and n* types respectively). Owing to the low position of the T * and T _n* levels relative to the singlet level of * type, the rate constant for intercombination conversion is greater than the rate constant for radiative decay. Consequently an efficient population of the triplet states of the molecules occurs under conditions of electronic-vibrational excitation. The direction of reactions during synthesis was compared with the localization indices in the ground state for electrophilic, nucleophilic, and radical substitution, and also with the excitation localization numbers L for a wide selection of electronically excited states. It was concluded that the change in the structure of the azole molecule on replacing an O atom by an S atom, or on changing from a partially hydrogenated to a heteroaromatic system, was the main reason for the change of all the spectral parameters characterizing the electronic-vibrational or the spin-orbital interaction of the most reactive groups of atoms in the molecular structure.     

Thermodynamics of dissolution of non-electrolytes and electrolytes in non-aqueous solvents

Experimental results on the H _soln of noble gases, polar non-electrolyte molecules, porphyrins, their metallocomplexes and organic electrolytes in individual and mixed solvents are discussed. Xe was shown to indicate changes in solvent mixtures and also to exert a noticeable influence on the character of intermolecular interactions in solutions. The thermodynamic characteristics of the solvation of a series of non-polar and polar molecules are given and their dependence on the solvent nature, composition, isotopy and temperature is shown. For the first time the thermodynamic characteristics of porphyrins and metalloporphyrins in different non-aqueous solvents have been found by direct calorimetry. The possibility of axial coordination of porphyrin metallocomplexes is treated and a method is proposed for estimation of the influence of the functional substituents and the metal atom on the electronic effects in them. Compared to simple inorganic electrolyte solutions, the dependence of H _soln on various factors reveals a specific character.

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Zusammenfassung Experimentelle Daten zur Lösungswärme H _soln von Edelgasen, polaren Nichtelektrolyten, Porphyrinen und ihren Metallkomplexen und organischen Eletrolyten in einfachen und gemischten Lösungsmitteln werden diskutiert.Es wird gezeigt, dass Xe nicht nur auf Veränderungen in der Zusammensetzung von Lösungsmittelmischungen anspricht, sondern selbst einen merklichen Einfluss auf den Charakter der intermolekularen Wechselwirkungen ausübt. Thermodynamische Charakteristika der Solvatation einer Reihe unpolarer und polarer Moleküle werden aufgeführt und die Abhängigkeit von der Natur, Zusammensetzung (auch isotopisch) und Temperatur des Lösungsmittels wird gezeigt. Erstmalig werden die thermodynamischen Charakteristika von Porphyrinen und Metallporphyrinen in verschiedenen Lösungsmitteln direkt kalorimetrisch bestimmt. Die Möglichkeit einer axialen Koordination an Metall-Porphyrin-Komplexen wird gezeigt und eine Methode zum Abschätzen des dabei wirkenden Einflusses der funktioneilen Substituenten und des Metallatoms auf die elektronischen Effekte vorgeschlagen. Verglichen mit einfachen anorganischen Elektrolyt-Lösungen ist' die Abhängigkeit von H _soln von verschiedenen Faktoren sehr substanzspezifisch.

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H _pactb. , , , . , . , . . . , H _pactb. .

     

Synthesis and thermal decomposition of (NH4)2[MIIIF5(H2O) (M=Al,Fe and Cr)

Ammonium pentafluorometallate monohydrates were prepared by different methods and characterized by chemical analysis, IR spectrometry and X-ray diffraction. Unit cell parameters were determined for the Fe and Cr compounds, which were found to be isostructural with the known Al compound. The IR spectra, X-ray diffraction patterns and lattice data on the compounds are very similar, and point to the existence of isolated [M^IIIF₅(H₂O)]^2– octahedra. The water is coordinated to theM ^III cation.Dehydration and thermal decomposition were investigated by thermal analysis (TG, DTG, DTA) on the Q-derivatograph and by high-temperature X-ray diffraction. Different dehydration temperatures and products were found, depending on the nature of theM ^III cation. NH₄F is liberated in several steps (Al or Fe) or continuously (Cr), leading to the formation ofM ^III fluorides.

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Zusammenfassung Ammoniumpentafluormetallat-monohydrate (NH₄)₂MeF₅ · H₂O (M=Fe, Al, Cr) wurden nach verschiedenen Methoden präpariert und durch chemische Analyse, IR-Spektren und Röntgenbeugung charakterisiert. Die Elementarzellen-Parameter der mit der Al-Verbindung isostrukturellen Fe- und Cr-Verbindung wurden ermittelt. IR-Spektren, Röntgenbeugungsdiagramme und Gitterdaten aller drei Verbindungen sind einander sehr ähnlich und beweisen das Vorliegen isolierter [M^IIIF₅(H₂O)]^2– -Oktaeder, in denen Wasser mit dem Kation koordiniert ist. Entwässerung und thermische Zersetzung wurden durch simultane TG-DTG-DTA und durch Hochtemperatur-Röntgenbeugung untersucht. Abhängig vom KationM ^III werden unterschiedliche Reaktionsprodukte und -temperaturen gefunden. Unter kontinuierlicher (M=Cr) oder schrittweiser Freisetzung von NH₄F (Fe, Al) wird das jeweilige Fluorid M^IIIF₃3 gebildet.

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, . , , . , . [M^IIIF₅(H₂O)]^2–, ^III. Q- , , . , M^III. , , — , .

     

The solid-state structure of (+)-(i)-menthyl 2-formamido-4, 4,4-trifluorobutanoate and the hydrogenation of the 2-butenoate precursor

Hydrogenation ofZ-(–)-(1R, 3R, 4S)-menthyl 2-formamido-4,4,4-trifluoro-2-butenoate catalyzed by Pd/C was performed at atmospheric pressure to yield a mixture of (2R, 1R, 3R, 4S)- and (2S, 1R, 3R, 4S)-menthyl 2-formamido-4,4,4-trifluorobutanoate diastereomers in a 5545 ratio, respectively. Repeated fractional crystallization from ethyl acetate and vapor diffusion of petroleum ether afforded (+)–(2S, 1R, 3R, 4S)-menthyl 2-formamido-4,4,4-trifluorobutanoate as clear colorless, crystalline prisms which were subjected to single-crystal X-ray diffraction analysis. The crystals belong to the orthorhombic system P2₁2₁2₁, and at 213 K:a=5.054(1),b= 10.000(2),c=32.707(1) Å,V=1652.9(4) ų,Z=4,R(F)=0.040, andR _w (F)=0.037. The finding of the (2S)-configuration for the formamido-acid portion of the (+)-ester enabled the configurational assignment of the asymmetric hydrogenation products ofZ-methyl 2-formamido-4, 4,4-trifluoro-2-butenoate catalyzed by chiral diphosphine/rhodium(I) complexes.     

Dehydrations of Ca(H2PO4)2·H2O and Mg(H2PO4)2·2H2O and their reactions with KCl,examined with simultaneous TG,DTG, DTA and EGA

The dehydrations of Ca(H₂PO₄)₂·H₂O and Mg(H₂PO₄)₂ H₂O were examined with a simultaneous TG, DTG, DTA and EGA method, partly under conventional, and partly under quasi-isothermal and quasi-isobaric conditions. It was found among others that the dehydrations of the examined compounds took place gradually between 100 and 500°, a series of intermediates being formed. The end-products were [Ca(PO₃)₂]₃ and Mg(PO₃)₂. The reactions of these hydrates with KCl were also examined. The many subsequent part reactions could be described by the following overall equation: 3 Ca(H₂PO₄)₂ + 2 KCl=Ca₂P₂O₇ + Ca(PO₃)₂ + 2 KPO₃ + 2 HCl + 5 H₂O It is noteworthy that the reactions do not lead to the formation of orthophosphates, but stop after the liberation of 2 moles of HCl.

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Zusammenfassung Die Autoren untersuchten die Dehydratisierung von Ca(H₂PO₄)₂·H₂O und Mg(H₂PO₄)₂·2H₂O. Zu den Untersuchungen wurde die simultane Methode von TG, DTG, DTA und EGA teils unter konventionellen, teils unter quasi isothermen und quasi isobaren Bedingungen eingesetzt. Die Autoren fanden u.a., daß die Dehydratisierung der untersuchten Verbindungen zwischen 100 und 500 °C stufenweise verlief, während eine Reihe von Zwischenprodukten gebildet wurde. Die Endprodukte waren [Ca(PO₃)₂]₃ bzw. Mg(PO₃)₂. Die Autoren prüften auch die Reaktion der erwähnten Hydrate mit KCl. Sie fanden, daß die zahlreichen aufeinanderfolgenden Teilreaktionen durch folgende Bruttoreaktion beschrieben werden können: 3Ca(H₂PO₄)₂ + 2KCl=Ca₂P₂O₂ + Ca(PO₃)₂ + 2KPO₃ + 2HCl + 5H₂O. Es ist bemerkenswert, daß die Reaktionen nicht zur Bildung von Orthophosphaten führen, sondern daß sie nach Freisetzung zweier Moleküle von HCl zum Stillstand kommen.

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Résumé Les auteurs ont étudié la déshydratation de Ca(H₂PO₄)₂·H₂O et Mg(H₂PO₄)₂·2 H₂O. Les méthodes de TG, TGD, ATD et AGE on été utilisées simultanément en partie dans les conditions conventionelles et en partie dans les conditions quasi isothermes et quasi isobares. Les auteurs ont trouvé, entre autres, que la déshydratation de ces composés a eu lieu de façon graduelle entre 100 et 500 °C, avec formation d'une série de produits intermédiaires. Les produits finaux sont respectivement [Ca(PO₃)₂]₃ et Mg(PO₃)₂. Les auteurs ont également examiné la réaction des hydrates mentionnés avec KCl. Ils ont trouvé qu'un grand nombre de réactions partielles consécutives peut être décrit par la réaction brute suivante: 3 Ca(H₂PO₄)₂ + 2 KCl=Ca₂P₂O₇ + Ca(PO₃)₂ + 2 KPO₃ + 2 HCl + 5 H₂O. Il est remarquable que les réactions n'entraînent pas la formation d'orthophosphates mais qu'elles s'arrêtent après l'élimination de 2 moles de HCl.

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(₂₄)₂ ·₂ Mg(H₂PO₄)₂ 2H₂O. , , . , 100–500° . , , [(₃)₂]₃ Mg(PO₃)₂. l. , : 3(₂₄)₂ + 2KCl=₂₂₇ + (₃)₂ + 2₃ + 2l + 5₂ , , l.

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The authors wish to thank Prof. E. Pungor for his interest in this work.     

Triterpene Glycosides of Tetrapanax papyriferum. I. Isolation and Structure of Glycosides St-H2 and St-I2 from Stem Bark

Stem bark ofTetrapanax papyriferumC. Koch., Araliaceae, yielded new triterpene glycosides 28-O--L-rhamnopyranosyl-(14)-O-(6-O-acetyl--D-glucopyranosyl)-(16)-O--D-glucopyranosyl esters of the 3-O-[-D-glucopyranosyl-(13)-[-D-galactopyranosyl-(12)]-O--L-arabinopyranosides of oleanolic and echinocystic acids. The structures of these substances were established using chemical and physicochemical methods     

Effect of adsorbed water on the activity of MoO3 catalysts in the double bond isomerization of olefins

Adsorbed water on molybdena catalysts calcined at different temperatures, may both increase or decrease the catalytic activity, depending upon the mode of adsorption and the number of adsorbed molecules. Our results prove that Brönsted acidic hydroxy groups are principal parts of the active sites, and Lewis acidic and/or basic centers are also required for catalytic activity in the double bond isomerization of olefins.

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, , , , . , , / .