Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

Kinetic Analysis of the Decomposition of Chelates of Di-alkyldithiocarbamate of Cd(II)

The thermal decomposition kinetics of the solid complexes Cd(S₂ CNR₂ )₂ , where R =C₂ H₅ , n -C₃ H₇ , n -C₄ H₉ or iso -C₄ H₉ , was studied by using isothermal and non-isothermal thermogravimetry. The superimposed TG/DTG/DSC curves revealed that thermal decomposition reactions occur in the liquid phase. The kinetic model that best fitted the experimental isothermal TG data was the one-dimensional phase-boundary reaction-controlled process R₁ . The thermal analysis data suggested the thermal stability sequence Cd(S₂ CNBuⁿ ₂ )₂ >Cd(S₂ CNPrⁿ ₂ )₂ >Cd(S₂ CNBuⁱ ₂ )₂ >Cd(S₂ CNEt₂ )₂ , which accords with the sequence of stability of the apparent activation energies. This revised version was published online in July 2006 with corrections to the Cover Date.     

Relative stability of isomers of polynuclear complexes of molybdenum oxides

Molybdenum(VI) oxide MoO₃ has been studied and the composition of polynuclear molybdenum oxides in the gas phase Mo _x O_{3x ? y} (x = 1–6, y = 0–2) has been determined by laser desorption/ionization time-of-flight mass spectrometry. Quantum-chemical calculations of bond energies, interatomic distances, charge distributions, and molybdenum-molybdenum bond orders for the isomers of neutral polynuclear molecular compounds Mo _x O3 _{x ? y} have been performed with the use of the PBE functional with a relativistically corrected potential implemented as the PRIRODA program package. On the basis of the bond energies, the relative stability of the isomers has been estimated. For the Mo _x O _y isomers (x ≥ 3), cyclic structures have been predicted to be more favorable. For the predicted most stable isomers of each Mo _x O _y composition, the bond energies of their positive and negative ions have been calculated. The positive ionization of Mo _x O _y leads to a considerable decrease in the bond energy of the isomer and the negative ionization, to its increase by about 0.1 au.     

Heats of formation of multi-substituted positive ions of organic species

The difference (ΔΔ_fH°) between heats of formation of many multi-substituted odd- and even-electron positive ions can be described by a linear equation: ΔΔ_fH° = A + Bm, where m is the number of substituents or ligands, relative to the unsubstituted reference ion, and m = 1, 2 or 3; A and B are the intercept and slope, respectively. The correlation quality for 59 types of odd- and 26 types of even-electron ions, which involve C, Si, Sn, H, F, Cl, Br, I, O, S, N and P atoms, was analyzed. Unknown heats of formation of related ions and the proton affinities of some organic molecules were predicted using the linear equation.     

Graphical representation of the state of orientation of polymer systems

The orientation distribution function for noncrystalline structural units in polymer systems cannot be determined completely from any experimental source; only the second and/or fourth moments of the distribution function, i.e., the second and/or fourth orders of the generalized orientation factors F_lm^j, can be evaluated. It is there-fore necessary to estimate the distribution function from F_2m^j and F_4m^j. In this paper, a graphical representation of the state of orientation is first discussed in terms of plots of F₄₀^j against F₂₀^j for several types of distribution functions for uniaxial orientation. These are three types of extreme concentration of the distribution at particular polar angles θ₀ given by θ₀ = 0, 0<θ₀<π/2, and θ₀ = π/2; five types of rather realistic distributions having single maxima at θ_j = 0, θ₀, π/2 and double maxima at θ_j = 0, π/2, and a single minimum at θ_j = θ₀; and four types of more realistic distributions including Kratky's floating rod model in an affine matrix. Second, estimation of the distribution function for uniaxial orientation from F₄₀^j and F₂₀^j is discussed quantitatively in terms of the mean-square error by three approximation methods: (a) expansion of the distribution function in finite series of spherical harmonics through the fourth order, (b) approximation of the distribution function as a composite of two components, random orientation and a particular orientation distribution given by N_a (cos²θ_j)^a, N_a being a constant, and (c) approximation of the distribution function by N_a (cos²θ_j)^a alone. It is concluded that when the orientation distribution is sharp, estimation by the second method of approximation gives a smaller error than the first.     

Synthesis of anthrathiopyrantriones by heterocyclization of alkynoyl derivatives of chloroanthraquinones

A procedure was developed for the synthesis of 2-substituted, including 2-alkenyl-substituted, 4H-anthra[1,2-b]thiopyran-4,7,12-triones and 4H-anthra[2,3-b]thiopyran-4,6,11-triones by cyclocondensation of vic-alkynoylchloroanthraquinones with Na₂S.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2205–2209, October, 2004.     

Enthalpy of formation of triphenylphosphine sulfide

The first measurements of the enthalpies of combustion, sublimation, and fusion of an organo-phosphorus sulfide, triphenylphosphine sulfide, are reported: _c H _m ^o (C₁₈H₁₅PS, cr)=–(10752.58 ±2.90), _sub H _m ^o (C₁₈H₁₅PS, 403 K)=(136.80±6.09), and _fus H _m ^o (C₁₈H₁₅PS, T_m=435.92 K) =(30.53±0.21) kJ·mol^–1. Correction of the phase change enthalpies toT=298.15K and p^o =0.1 MPa results in the standard phase change enthalpy values of _sub H _m ^o (298.15 K)=(142.8 ±6.8) and _fus H _m ^o (298.15 K)=(19.28±0.21) kj·mol^–1. Accordingly, the enthalpies of formation of solid, liquid, and gaseous triphenylphosphine sulfide are derived: _f H _m ^o (C₁₈H₁₅PS, cr) =(63.20±2.56), _fH _m ^o (C₁₈H₁₅PS, l)=(82.48±2.57), and _fH _m ^o (C₁₈H₁₅PS, g)=(206.0±7.3) kJ·mol^–1. From these ancillary data, the P=S double-bond enthalpy is 394 kJ-mol^–1 and in good agreement with earlier reaction calorimetry results. These phosphorus sulfide values are compared with those for the arsenic sulfides. Plausibility arguments are given for our results.     

Application of the theory of design of experiments in examination and elimination of the matrix effect

Summary A method of experimental optimization of an analytical procedure aimed at elimination of the matrix effect is proposed which is based on the theory of design of experiments. The criterion functions Q are formulated, which are expressed by regression coefficients in the empirical mathematical model approximating the relationship between a quantity R and the concentrations of sample components. R denotes, for example, the measured signal (e.g. absorbance, emission intensity), the concentration of a component being determined read from the calibration graph, or the error of determination. The quantities Q depend, in general, on the conditions of analysis which can be expressed by the factors z ₁..., z _M (e.g., in AAS — observation height, gas flux, concentrations of the auxiliary substances in a sample, etc.). It is assumed that the extreme of a function Q corresponds to the optimum conditions of analysis. In this paper the relationship between a quantity Q and the factors z is approximated by the polynomial model. The regression coefficients in this model are estimated on the basis of the results of an experiment carried out according to the composite rotatable design. The extreme of the model is found mathematically. Various criterion functions Q are discussed. An example concerning determination of Mg and Ca in AlCl₃ reagent by AAS is presented.

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Anwendung der Theorie der Versuchsplanung zur Untersuchung und Eliminierung des MatrixeffektsBestimmung von Mg and Ca in AlCl₃ mit Hilfe der AAS

Zusammenfassung Ein auf der Theorie der Versuchsplanung beruhendes Verfahren zur experimentellen Optimierung einer analytischen Methode mit dem Ziel der Eliminierung des Matrixeffekts wird beschrieben. Die Kriteriumfunktionen Q werden formuliert, die durch Regressionskoeffizienten in einem mathematischen Modell ausgedrückt werden, das der Beziehung zwischen einem Wert R und den Konzentrationen der Bestandteile angenähert ist. Hierbei bedeutet R z. B. das gemessene Signal (Extinktion, Emissionsintensität), den von der Eichkurve abgelesenen Konzentrationswert oder den Fehler der Bestimmung. Der Wert Q hängt im allgemeinen von den Analysenbedingungen ab, die durch die Faktoren z ₁... z _M (bei der AAS zum Beispiel die Beobachtungshöhe, der Gasstrom, die Konzentration von Hilfssubstanzen usw.) ausgedrückt werden können. Es wird angenommen, daß der Extremwert einer Funktion Q den optimalen Analysenbedingungen entspricht. Die Beziehung zwischen Q und den Faktoren z wird durch ein Polynommodell angenähert. Die Regressionskoeffizienten in diesem Modell werden aufgrund von Versuchsergebnissen bestimmt. Der Extremwert des Modells wird mathematisch berechnet. Verschiedene Kriteriumfunktionen Q werden diskutiert. Als Beispiel wird die Bestimmung von Mg und Ca in AlCl₃ mit Hilfe der AAS beschrieben.

     

Effect of the degree of sulfoethylation of polyethylenimine on the selectivity of sorption of palladium(ii) from binary solutions

Poly(N-2-sulfoethylethylenimine) (SEPEI) with a degree of modification equal to 0.30, 0.58, and 0.74, cross-linked with diethylene glycol diglycidyl ether, demonstrates efficient sorption properties with respect to Pt^IV, Pd^II, and Au^III ions. The selectivity coefficient K_Pd/Au in a HCl solution with pH 0.8 decreases from 90 to 61, and the selectivity coefficient K_Pd/Pt in a HCl solution with pH 3.9 increases from 0.94 to 480 with an increasing degree of modification. A thiourea hydrochloric acid solution effectively removes metal ions; the desorption of Pt^IV, Pd^II, and Au^III from the SEPEI surface reaches 100, 96.9, and 83.8%, respectively.

     

A study of the alkaloids of plants of the genusStephania

Summary Four alkaloids have been isolated from the tubers ofStephania glabra (Roxb.) Miers. (synonymSt. rotunda Lour.) collected in the Democratic Republic of Vietnam:l-tetrahydropalmatine and three previously undescribed bases (A -C₁₉H₁₈O₂N, C - C₂₀H₂₅O₄N, and D -C₂₁H₂₅O₄N).Khimiya Prirodnykh Soedinenii, Vol. 1, No. 6, pp. 392–394, 1965.The substances in this paper are denoted by letters. The novelty of these substances has not been established, which contradicts the rules of this journal. The paper is printed as an exception (Editiorial Board).     

Mechanism of thermal decomposition of hydrogenphosphities

Evolution of hydrogen during thermal decomposition of some M^IIHPO₃ (M= Mg, Ca, Zn, Sr, Cd, Ba) phosphities under nitrogen atmosphere was investigated. Step mechanism of thermal decomposition has been proposed.

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Zusammenfassung Es wurde die Wasserstoffentwicklung während der thermischen Zersetzung einiger Phosphite M^II)HPO₃ (mitM=Mg, Ca, Zn, Sr, Cd, Ba) in einer Stickstoffatmosphäre untersucht. Es wurde ein schematischer Mechanismus für die thermische Zersetzungsreaktion gegeben.

     

Thermochemical studies for determination of the molar enthalpy of formation of aniline derivatives

The standard (p ^o=0.1 MPa) molar enthalpies of combustion atT=298.15 K were measured by static bomb combustion calorimetry for liquidN,N-diethylaniline,N,N-dimethyl-m-toluidine,N,N-dimethyl-p-toluidine, andN-ethyl-m-toluidine. Vaporization enthalpies forN,N-dimethyl-m-toluidine andN-ethyl-m-toluidine were determined by correlation gas chromatography. Derived standard molar values of _f H _m ^o (g) at 298.15 K forN,N-diethylaniline (62.1±7.6);N,N-dimethyl-m-toluidine (72.6±7.3),N,N-dimentyl-p-toluidine (68.9±7.4),N-ethyl-m-toluidine (30.5±3.8 kJ· mol^–1) were obtained.     

Kinetics of Formation of Peroxyacetic Acid

The kinetics of the reaction of acetic acid with hydrogen peroxide, leading to peroxyacetic acid, were studied at various molar reactant ratios (AcOH-H₂O₂ from 6 : 1 to 1 : 6) at 20, 40, and 60°C and sulfuric acid (catalyst) concentrations of 0 to 9 wt %. The reaction is reversible, and the equilibrium constant decreases as the temperature rises: K = 2.10 (20°C), 1.46 (40°C), 1.07 (60°C); Δ_r H ⁰ = − 13.7±0.1 kJ mol⁻¹, Δ_r S = −40.5±0.4 J mol⁻¹ K⁻¹. The maximal equilibrium concentration of peroxyacetic acid (2.3 M) is attained at 20°C and a molar AcOH-to-H₂O₂ ratio of 2.5 : 1. The rate constants of both forward and reverse reactions increase with increase in sulfuric acid concentration from 0 to 5 wt %. Further raising the catalyst concentration does not affect the reaction rate. The reaction mechanism is discussed.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 7, 2005, pp. 1187–1193.Original Russian Text Copyright © 2005 by Dul’neva, Moskvin.     

Flavonoids of inflorescences of Calendula officinalis

By column chromatography on polyamide sorbent, the inflorescences of pot marigold calendula have yielded eight substances of flavonoid nature: two aglycons — quercetin (C₁₅H₁₀O₇, mp 309–311°C) and isorhamnetin (C₁₆H₁₂O₇, mp 314–316°C); six glycosides, of which three have been identified as isoquercetin (C₂₁H₂₀O₁₂, [] _D ²⁰ –36° in methanol, mp 218–220°C), isorhamnetin 3-O--D-glucoside (C₂₂H₂₂O₁₂, [] _D ²⁰ –59° in dimethylformamide, mp 193–195°C), narcissin (C₂₈H₃₂O₁₆, [] _D ²¹ –28° in dimethylformamide, mp 180–182°C), and three substances that have proved to be new and have been called calendoflaside (C₂₈H₃₂O₁₅, [] _D ²¹ –85° in methanol, mp 192–195°C; calendoflavoside (C₂₈H₃₂O₁₆, [] _D ²⁰ –106° in methanol, mp 189–192°C), and calendoflavobioside (c₂₇H₃₀O₁₆, [] _D ²⁰ –105° in methanol, mp 194–197°C).All-Union Scientific-Research Institute of Drug Chemistry, Khar'kov. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 795–801, November–December, 1988.     

Synthesis of N-glycoconjugates of glycyrrhetic acid

New N-glycoconjugates that are analogs of glycyrrhizic acid were synthesized by condensation of α-L-rhamnopyranosylamine and β-D-lactosylamine with acid succinate and phthalate of glycyrrhetic acid methyl ester using N,N′-dicyclohexylcarbodiimide (DCC) or DCC-N-hydroxybenzotriazole. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 54–56, January–February, 2006.     

Properties of solution-grown crystals of fractions of isotactic polypropylene with different degrees of stereoregularity

Solution-grown crystals of fractions of isotactic polypropylene (IPP) with different degrees of stereoregularity have been obtained by isothermal crystallization from α-chloronaphthalene, using a self-seeding technique. Electron micrographs of samples, crystallized under the same undercooling, show that, with decreasing fraction of isotactic pentads, the perfect rectangular shape of the single crystal is lost and the presence of more complex morphologies is increasingly observed. The equilibrium dissolution temperature T_d of IPP fractions, from polymers prepared with a titanium based catalyst, decreases linearly with decreasing percentage of isotactic pentads. An extrapolated value of 171°C is obtained for the equilibrium dissolution temperature of a crystal of IPP with 100% isotactic pentads, i.e., an IPP crystal free of configurational defects. The melting temperature T′_m and the apparent enthalpy of fusion ΔH of crystallized and annealed crystal aggregates have been determined by differential calorimetry. The equilibrium melting temperature T_m also depends greatly upon the isotactic pentad concentration. For 100% concentration the extrapolated value of T_m is 181°C. T_m decreases about 1°C per 1% decrease in the isotactic pentad population. The observed equilibrium melting and dissolution temperature depression does not follow the predictions of the Flory equation for copolymer crystallization. In fact, the effect of decreasing probability of isotactic sequence propagation is to depress T_d and T_m much more rapidly. The apparent enthalpy of fusion of both solution-grown crystals and melt-recrystallized samples decreases with an increase in the number of configurational impurities along the chain. For the most stereoregular fraction the average length of isotactic stereoblocks has been compared with the lamellar thickness of solution-grown lath-shaped single crystals.     

Thermodynamic functions of buthylderivatives of ferrocene

The heat capacity of isobuthanoylferrocene, C₅H₅FeC₅H₄-COCH(CH₃)₂, was measured by low-temperature adiabatic calorimetry. The purity, temperature, and enthalpy of fusion were obtained. The ideal gas thermodynamic functions were derived at T = 298.15 K. The purity and thermodynamic functions of fusion of isobuthylferrocene, C₅H₅FeC₅H₄-CH₂CH(CH₃)₂, were obtained by differential scanning calorimetry. The sample was synthesized by the reduction of isobuthanoylferrocene obtained by the direct acylation of ferrocene.     

Thermobarometric analysis of physico-chemical transformations of coacervates and gels of polyphosphates

By thermobarometric analysis, we have investigated gels and coacervates of polyphosphates systems (x MO-y P₂O₅-z CaO-n H₂O, whereM=Na or Mg) and studied their physico-chemical transformations until 1000 bars. In every case, the same general shape is obtained for the thermobarograms. A strong pressure increment is first observed bounded to the expansion of the sample under temperature effect. Then, between 100 and 110C, a free water release is detected by an important and progressive decrement of pressure issue from a strong volume decrement. At higher temperature, the hydrolysis of the systems is turned into pressure increments. Such experiments are the first showing that, by thermobarometric analysis, physico-chemical transformations can be easily studied. Moreover, for the first time, a negative volume change at a transformation obtained by increasing the temperature has been able to be observed by thermobarometric analysis.

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Zusammenfassung Mittels thermobarometrischer Analyse wurden Gele and Coacervate von Polyphosphat-Systemen (xMO-y P₂O₅-z CaO-n H₂O, mitM-Na oder Mg) untersucht und auf physikochemische Umwandlungen bis 1000 bar geprüft. Die generelle Form der Thermobarogramme ist in allen FÄllen dieselbe. Zuerst wird ein starkes Druckinkrement beobachtet, das auf die Probenexpansion unter Temperatureinfluss zurückgeht. Dann, zwischen 100 und 110C, wird die Abgabe von freiem Wasser durch eine ausgeprÄgte und progressive Abnahme der Druckwirkung infolge starker Volumabnahme angezeigt. Bei höherer Temperatur wirkt sich die Hydrolyse des Systems in Form von Druckinkrementen aus. Diese Experimente belegen erstmals, dass durch thermobarometrische Analyse physikochemische Umwandlungen leicht zu untersuchen sind. Darüber hinaus ist es zum ersten Mal gelungen, eine mit zunehmender Temperatur bei einer Umwandlung eintretende negative VolumÄnderung thermobarometrisch zu beobachten.