Alkaloids of Nitraria schoberi. N-Methylnitrarine

Nitrarine, isonitrarine, schoberidine, isoschoberidine, nitramidine, nitraroxine, nitraraine, schoberine, dehydroschoberine, tetramethylenetetrahydro--carboline, dl-vasicinone, deoxypeganine, deoxyvasicinone, dihydronitraraine, nitraramine, nitraramine N-oxide, tetramethylenetetrahydro--carboline N-oxide, tryptamine, and a new alkaloid N-methylnitrarine were isolated from the aerial part ofNitraria schoberiL. Spectral data and chemical transformations were used to establish the structure of the last, which was found in nature for the first time.     

Cumene hydroperoxide decomposition in the presence of metal complex catalysts supported on amorphous SiO2

By the method of molecular deposition, ions of CrO ₂ ²⁺ VO³⁺ and MoO ₂ ²⁺ were supported on a matrix of amorphous SiO₂. Different types of organic ligands were supported subsequently on the surface compounds so formed. The catalytic activity of the samples was studied in the decomposition of comene hydroperoxide.

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SiO₂ CrO ₂ ²⁺ , VO³⁺, MoO ₂ ²⁺ . . .

     

Effect of complexation on electrical conductivity in system consisting of an anion-radical salt and a crown ether

Various experimental methods have been used in a study of the effect of complexation on the electrical conductivity in systems consisting of an anion-radical salt of an alkali metal, a crown ether (CE), and a polar solvent. The electrical conductivity of solutions of M⁺TCQDM (TCQDM = tetracyanoquinodimethane) in the presence of the CE is determined by the ratio () of the radius of the CE cavity to that of the metal ion. The equilibrium constants of the processes taking place in these systems have been determined. It has been established that the electrical conductivity of the systems is determined by the following: a) electrostatic interaction (with = 0–0.8 and > 2); b) formation of complexes {M⁺...CE (with }- 1); c) formation of ternary associates {A...M⁺...CE (with }- 1.4). In the last case, the symmetry of the environment of the M⁺ ion is increased and the potential barrier to the transition of ions between the equilibrium positions is lowered, which is responsible for the observed increase in mobility of the ions in solution.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 22, No. 2, pp. 188–196, March–April, 1986.     

Terpenoids of Artemisia splendens

d-Camphor, -borneol, stearic acid, -sitosterol, austricin, and a new sesquiterpene lactone which has been called splendolide have been isolated from the epigeal part ofArtemisia splendens Willd. The structure of splendolide has been established as 1-hydroxy-6H,7H-eudesma-4,11(13)-dien-6,12-olide.Instiutte of Botany, Academy of Sciences of the Azerbaidzhan SSR, Baku. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 203–206, March–April, 1991.     

Frequencies, anharmonicities, and dissociation energies of OH groups in H-mordenite

Harmonic frequencies, anharmonicities and dissociation energies of surface hydroxy groups in H-mordenite have been determined. The application of the Lippincott-Schroeder potential function for similar problems is proposed.

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, -. - .

     

Meaningful activation energies for complex systems II

The validity of the Friedman method is assessed for systems of overlapping reactions. By means of mathematical analysis and numerical examples it is shown that, in the case of competitive reactions, the method gives the true value of the instantaneous mean activation energy. However, some error may be incurred if this method is applied to systems of independent reactions. The relative accuracy of the Friedman and Ozawa-Flynn-Wall methods is discussed in respect of complex systems of reactions.

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Zusammenfassung Die Gültigkeit der Friedman-Methode wird für Systeme von überlappenden Reaktionen einer Betrachtung unterzogen. Durch mathematische Analyse und numerische Beispiele wird gezeigt, daß im Falle kompetitiver Reaktionen die Methode den richtigen Wert der jeweiligen mittleren Aktivierungsenergie ergibt. Fehler können jedoch auftreten, wenn diese Methode auf Systeme voneinander unabhängiger Reaktionen angewandt wird. Die relative Genauigkeit der Methoden von Friedman und Ozawa-Flynn-Wall wird mit Hinsicht auf komplexe Reaktionssysteme diskutiert.

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. , . , , . -- .

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The author wishes to thank the British Gas Corporation for permission to publish this work.     

AlPO4?ZrO2 catalysts, IV. Cyclohexene skeletal isomerization activity of systems obtained in ethylene oxide

The use of AlPO₄–ZrO₂ (weight ratio AlPO₄/ZrO₂=3) as catalyst systems obtained with ethylene oxide and subjected to different stages of heat treatments has been studied through their catalytic activity in the skeletal isomerization of cyclohexene to 1- and 3-methylcyclopentenes (1- and 3MCP). The apparent rate constants and selectivity to 1-MCP are used for an evaluation of the presence and amount of strong acid sites, the only ones capable of giving rise to skeletal isomerization. The decrease in catalytic activity as calcination increases is consistent with not only the decrease in the amount of acid sites measured vs. weaker organic bases but also with the decrease in Brönsted acidity, as shown by the decrease in O–H band intensity.

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AlPO₄–ZrO₂ ( AlPO₄/ZrO₂=3), , 1- 3- (1- 3-). 1- , . , , , O–H.

     

Selective hydrogenation of fatty oils on alloyed Ni?Al catalyst. I. Kinetic model

On the basis of literature data concerning the reaction mechanism, a kinetic model for the selective hydrogenation of cotton-seed oil on the S-3 commercial alloyed Ni–Al catalyst is suggested. Its parameters have been identified according to the experimental data obtained in an agitated slurry reactor at T=140–200°C and P=0.2–0.8 MPa.

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, C-3. , , t=140–120°C, P=0.2–0.8 .

     

Phytoecdysteroids of Rhaponticum carthamoides. II. Rhapisterone B

A new ecdysteroid (rhapisterone B) has been isolated from the seeds ofRhaponticum cathamoides (Willd.) Iljin. (familyCompositae). It has been shown that it is 2, 3, 11, 14, 20R, 24-hexahydroxy-5-cholest-7-en-6-one.Institute of the Chemistry of Plant Substances, Uzbek Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 806–808, November–December, 1991.     

Microwave enhancement of evaporation of a polar liquid. I

The evaporation of a polar liquid at low pressure and exposed to microwave radiation has been investigated, as an example of an endothermic reaction. A fixed, high column of liquid was irradiated in a waveguide with 2.45 MHz-CW microwave radiation. The temperatures of the gas and the liquid in contact with the interface and the evaporation rate were measured as functions of the non-equilibrium gas pressure and the microwave field.Empirical equations relating the dynamic non-equilibrium parameters to each other are given. The results show that microwave heating offers the possibility or reversing a temperature difference between the two phases at a gas-liquid interface. Other special features of the action of microwaves are discussed.

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Zusammenfassung Die Verdampfung einer bei niedrigem Druck der Einwirkung von Mikrowellenstrahlung ausgesetzten polaren Flüssigkeit wurde als Beispiel einer endothermen Reaktion untersucht. Eine fixierte, hohe Flüssigkeitskolonne wurde mit 2.450 MHz-CW-Mikrowellen bestrahlt. Die Temperature der mit der Grenzfläche in Kontakt befindlichen Gas- und Flüssigkeitsmenge und die Verdampfungsgeschwindigkeit wurden in Abhängigkeit vom Nichtgleichgewichts-Dampfdruck und Mikrowellenfeld gemessen. Empirische Gleichungen werden angegeben, die die dynamischen Nichtgleichgewichtsparameter miteinander in Beziehung bringen. Die Ergebnisse zeigen, dass Mikrowellenheizung die Möglichkeit bietet, die Temperaturdifferenz zwischen den zwei Phasen einer Gas-Flüssigkeits-Grenzfläche umzukehren. Andere spezielle Züge der Wirkung von Mikrowellen werden diskutiert.

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, , . , 2.450 -. . , . , . .

     

Monolayer vanadia on titania systems from alkoxide precursors. Part III. Activity in secondary alcohol oxidation

The activity of V⁵⁺ ion monolayer supported on anatase, rutile, and anatase-rutile mixed carrier and of bulk V₂O₅ was examined in isopropyl alcohol and cyclohexanol oxidation. Catalysts exhibited remarkable activity in ketone formation. At higher temperatures benzene was the predominant product of cyclohexanol reaction.

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V⁵⁺, , - V₂O₅, . . .

     

Studies on catalytically active surface compounds, IX. Formation of O2? radicals on VCl4/SiO2 catalysts

The conditions for the formation of O ₂ ^– on VCl₄/SiO₂ catalysts have been investigated. It is shown that thermal vacuum treatment (TVT) of unhydrolyzed catalysts leads to partial hydrolysis of the surface vanadium complex caused by the silanol groups of the support. The ability of the catalysts to generate O ₂ ^– radicals was found to depend on the degree of hydrolysis caused by thermal vacuum treatment.

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O ₂ ^– VCl₄/SiO₂. , , . , O ₂ ^– , .

     

Reactivity of allyl (o-halophenyl) ethers with organonickel (0) complexes

The reactivity of allyl (o-halophenyl) ethers with zerovalent nickel complexes, with triphenylphosphine and pyridine as ligands, leading to benzo[b]furan derivatives has been checked. Cyclization products were not isolated, but deallylation, substitution, reduction and rearrangement products were obtained in low to moderate yields. Mechanisms are proposed to explain the formation of these side products.

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-(o-) , , [b] . , , , , . .

     

Alkali hexamolybdochromates

Li, Na, K, Rb, Cs and NH₄ hexamolybdochromates have been prepared, characterized by X-ray and IR spectra, and their thermal behaviour was studied. We observed that the anion decomposition occurs only when the last 3 H₂O are eliminated. TheH values for this elimination decrease from the Li to the Cs salt in the same manner as the lattice energies found in other alkali salts with a common anion. The exothermic reactions in the decomposition of the complexes are interpreted by inspection of the compounds obtained.

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Zusammenfassung Die dargestellten Hexamolybdochromate von Li, Na, K, Rb, Cs und NH₄ wurden durch ihre Röntgen- und Infrarotspektren charakterisiert und ihr thermisches Verhalten studiert. Die Zersetzung des Anions begann erst nach Entweichen der letzten 3 H₂O. DieH-Werte dieses Vorganges sinken in derselben Weise vom Li zum Cs wie die Gitterenergien anderer Alkalisalze mit gleichem Anion. Die auf die Zersetzung folgenden exothermischen Reaktionen wurden durch Untersuchung der erhaltenen Verbindungen gedeutet.

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Résumé Examen du comportement thermique des hexamolybdochromates de Li, Na, K, Rb, Cs et NH₄ caraetérisés par leurs spectres de rayons X et infrarouges. La décomposition de l'anion ne commence qu'après l'élimination des 3 dernières molécules d'eau. Les valeursH de ce processus décroissent du sel de lithium à celui de césium de la même manière que les valeurs des énergies de réseau d'autres sels alcalins contenant le même anion. Interprétation des réactions exothermiques relatives à la décomposition des complexes par examen des composés obtenus.

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Li, Na, K, Rb, Cs NH₄, - , . , 3 H₂O. H Li- Cs- , , . , , .

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This work was supported by Consiglio Nazionale delle Ricerche.     

Thermal behaviour of transition metal complexes of dithiocarbazic esters. II

A thermal study (simultaneous TG and DTA measurements) was carried out on the dithiocarbazic ester complexes M[N³CH₂R₁N²C¹(S)SCH₃]₂, where M=Ni, Pt; R₁=C₆H₅. The following disproportionation reaction occurs in the solid state: II is formed through deprotonation of the CH₂ group bound to N³, whereas III is formed through protonation of N³.The influence of inductive and/or steric effects on the mechanism of this reaction is discussed, taking into account the electrochemical and X-ray data on the complexes Pt[NRNC(S)SR']₂ with differentR substituents: R=H, Ph, CH₂Ph, CH₂C₅H₁₁, CH(CH₃)₂, C(CH₃)₃; R=CH₃, CH₂Ph.These results accord with the behaviour of the same complexes in solution.

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Zusammenfassung Dithiokarbamidsäureesterkomplexe M[N³CH₂R₁N²C¹(S)SCH₃]₂ mit M=Ni, Pt und R₁=C₆H₅ wurden thermisch untersucht. Im festen Zustand spielt sich folgende Disproportionierungsreaktion ab: II wird durch Deprotonierung der an N³ gebundenen CH₂ Gruppe und III durch Protonierung des Atoms N² gebildet. Unter Zuhilfenahme der elektrochemischen und Röntgendaten der Komplexe Pt[NRNC(S)SR']₂ mit verschiedenen Substituenten R: R=H, Ph, CH₂Ph, CH₂C₅H₁₁, CH(CH₃)₂, C(CH₃)₃ und R=CH₃ bzw. CH₂Ph wurde der Einfluß von induktiven und/or sterischen Effekten auf den Reaktionsmechanismus diskutiert. Diese Ergebnisse stehen in Übereinstimmung mit dem Verhalten der Komplexe in Lösung.

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M[N³CH₂R₁N²C¹(S)SCH₃]₂, M= Ni, Pt,R ₁=C₆H₅. : II CH₂ , N³, III N². () , Pt[NRNC(S)SR]₂, R= , aR= . .

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We thank prof. A. La Ginestra for many helpful discussions on the various aspects of this work.     

Thermal decompositions of silver carboxylates

The thermal decompositions of the even silver dicarboxylates from silver oxalate to silver sebacate were studied. In vacuum, the dicarboxylates decomposed to give metallic silver, CO₂ and organic diradicals as primary products, and polymers as secondary products. The higher silver dicarboxylates were much more stable to thermal treatment than silver oxalate, probably due to the initiation of decomposition of all carboxylates except silver oxalate by the rupture of a Ag-O and not a C-C bond.

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Zusammenfassung Die thermische Zersetzung der geradzahligen Silberdicarboxylate Silberoxalat bis-sebacinat wurde untersucht. Unter Vakuum zersetzen sich die Dicarboxylate zu metallischem Silber, CO₂ und organischen Diradikalen als Primärprodukt und Polymeren als Sekundärprodukt. Die höheren Silberdicarboxylate sind wesentlich stabiler als das Oxalat, wahrscheinlich weil bei ihnen die Zersetzung von der Spaltung einer Ag-O-Bindung und nicht einer C-C-Bindung wie beim Oxalat ihren Anfang nimmt.

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, . , — . , . , , , Ag-O, -.

     

IR spectroscopic studies of surface acrolein and acrylic acid compounds in conditions of catalytic oxidation of acrolein on V?Mo?Si?O catalyst

Three surface complexes of acrolein have been identified by high-temperature IR spectroscopic method. Their extinction coefficients have been decermined. - .     

Radioimmunoassay of somatotropin using second antibody polyethylene glycol combination separation system

We describe a radioimmunoassay procedure for human somatotropin using second antibody — polyethylene glycol (PEG) combination for the separation of antibody bound and free antigen. The assay is done by a single incubation of 18 hours or with one hour pre-incubation and 3 hours post-incubation at room temperature (25 °C) and uses 0.1 m of serum sample. The assay covers a range of 0–40 g/ and has a sensitivity of 0.6 g/ of somatotropin. The assay is validated by inter-assay and intra-assay variations, recovery and parallelism tests.     

Invariant sets for kinetic equations

Some sets in the space of compositions possessing an invariance property are considered for a closed system, where a complex chemical reaction of a known mechanism proceeds. If the vector of concentrations belongs to such a set at a certain moment of time, it will remain within it at any succeeding moment. Some possible applications are discussed.

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, , , : , . .

     

Interpretation of TA-data for drugs: Ageing,reactions etc.

The drug systems bacampicillin (S and R epimers) and Alfa-water were investigated by TG-DSC, X-ray diffraction, microscopy, and density measurements. Both systems are mixtures of crystalline and amorphous materials; the interpretation of their effects and properties indicates that the solid samples in the mixture react with each other, even at room temperature. Consequently these results indicate that complex mixtures are present and that ageing is going on.

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Zusammenfassung Die Wirkstoff-Systeme Bacampillicin (S- und R-Epimer) und Alfa-Wasser wurden mittels TG und DSC, Röntgenbeugung, Mikroskopie und Dichtemessungen untersucht. Beide Systeme stellen Mischungen kristalliner und amorpher Stoffe dar; eine Deutung ihrer Effekte und Eigenschaften zeigt, dass die festen Stoffe in der Mischung miteinander reagieren, sogar bei Raumtemperatur. Die Ergebnisse beweisen das Vorliegen komplexer Mischungen und das Ablaufen von Alterungsvorgängen.

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(S R — ) - - , , . . , , , .