Stereochemical features of diterpene alkaloids in acylation and alkaline hydrolysis reactions

Summary Relative difficulty of saponifying an acetoxy group at C₁ and ease of acylation of a hydroxy group in this position as compared with a hydroxy group C₁₀ has been shown for alkaloids with a lycoctonine skeleton.The anomalously easy saponification of a C₁-acetoxy group in karakolidine acetates is due to the influence of the neighboring C₁₃-hydroxy group.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 381–383, May–June, 1975.     

Structure of iliensine

Summary On the basis of chemical reactions and spectroscopy, it has been shown that the new alkaloid iliensine has the lycoctonine skeleton with -hydroxy groups at C₃ and C₁₀, an -glycol system at C_7–8, -methoxy group at C₆ and C₁₅, a methoxymethyl group at C₄, and an iminoethyl group. A correlation has been made of iliensine with acomonine.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 770–775, November–December, 1975.     

NMR investigation of alkaloids I.13C NMR spectra and stereochemistry of pentacyclic oxindole alkaloids of the heteroyohimbine group of the epiallo and allo series

The¹³C NMR spectra of pentacyclic oxindole alkaloids of the heteroyohimbine group of the allo and epiallo series have been studied and an assignment has been made of the CSs of the carbon atoms. Characteristic differences have been noted in the¹³C CSs of the C₂, C₃, C₇, C₁₄, C₁₅, and C₁₉ carbon atoms that may be useful for solving stereochemical problems in new bases of this series from their¹³C NMR spectra.Communicated at the All-Union Conference on Recent Advances in High-resolution NMR spectroscopy, Tashkent, September, 1979 [1].Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 217–224, March–April, 1980.     

Experimental results relating to the metabolism of the cardiac glycosides

Summary 1. The metabolism of nine cardenolides — convallatoxin, convallatoxol, erychroside, erychrosol, securiside, securisidol, gofruside, frugoside, and erysimin — has been studied at the stage of passage through the liver and in the pathways of excretion by the kidneys.2. It has been found that the aldehyde at the C₁₉ group of the cardiac glycosides studied is reduced to an alcohol group.3. Erysimin differs in its metabolism from the other glycosides studied by the fact that in addition to the production of a form reduced at C₁₉ it undergoes hydrolytic cleavage with the production of the genin. A third metabolite has not been identified and has provisionally been called metabolite M.Khar'kov Scientific-Research Institute of Pharmaceutical Chemistry. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 658–662, September–October, 1973.     

Proof of the position of the methoxy groups in the aromatic nucleus of majdine and isomajdine by means of the intramolecular nuclear overhauser effect

Summary On the basis of measurements of the NOE, the position of the aromatic methoxy groups in majdine and isomajdine at C₁₁ and C₁₂ has been shown unambiguously, and an assignment has been made of the aromatic protons at C₉ and C₁₀.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 70–72, January–February, 1973.     

Partial synthesis of evonoloside

Conclusions The synthesis of evonoloside has been effected from cannogenol and L-rhamnose with a yield of 35%. It has been shown that when a primary alcohol group (at C₁₉) and a secondary axial hydroxy group (at C₃) are present in the aglycone, to introduce the sugar component at C₃ it is desirable first to protect the primary OH group by the partial acetylation of the aglycone.Khimiya Prirodnykh Soedinenii, Vol. 5, No. 1, pp. 20–22, 1969     

Structure of the tetrakis(benzoylacetonate) compound of europium used to obtain the laser effect

The spatial symmetry group of unit cells of diethylammonium and plperidinium europium tetrakis(benzoylactonate) B₄EuHD and B₄EuHP, and also the structure of the B₄Eu^– anion in B₄EuHD, which belongs to the C₂ symmetry group and exists as the cis, cis, cis isomer, have been determined. On the basis of an analysis of the luminescence spectra and structure of the B₄Eu^– anion it has been shown that the splitting of the levels of the ground state of the europium ion formally corresponds to C₂ symmetry, but may be determined by the C₄ symmetry of the immediate oxygen environment of europium EuO₈. Both complexes give a stable laser effect at a wavelength of 613 nm, corresponding to the transition from the ⁵D₀ level to the x- or y-component of the ⁷F₂ level, split by a crystal field with C₂ or C₄ symmetry.     

The structure of karakoline

Summary We have isolated from the tubers ofAconitum karakolicum collected in the Kirghiz SSR, Kungei Alatau range, songorine, napelline, a base with mp 159–160°C, and the new alkaloids karakoline and a base with mp 222–224°C.The results of a study of the chemical reactions and spectral characteristics of karakoline have shown that it consists of a lycoctonine skeleton with N-ethyl and C₄-methyl groups, hydroxyls at C₁, C₈, and C₁₀ and a methoxy group at C₁₅.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 199–205, March–April, 1973.     

Structure of acoseptine—A representative of a new type of norditerpenoid alkaloids

A new diterpenoid alkaloid, which has been called acoseptine, has been isolated from the plantAcontium septentrionale Koelle. This is the first alkaloid of the anhydrolycoctonine type with a C₈–C₁₇ bond and a carbonyl group at C₇. The structure of acoseptine has been established on the basis of IR, mass, and¹H and¹³C NMR spectra.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (371) 120 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 113–115. January–February, 1999.     

Alkaloids of Aconitum monticola structure of acomonine

Summary The roots ofAconitum monticola have yielded songorine, songaramine, norsongorine, an amorphous base with the composition C₂₂H₃₅NO₆, a base C₂₂H₃₃NO₆ with mp 166–167°C, a base C₂₂H₃₃NO₅ with mp 161–164°C, and the new alkaloid acomonine. The structure of acomonine has been established on the basis of chemical transformations and spectral properties: It consists of a lycoctonine nucleus with an -hydroxy group at C₃, an -methoxy group at C₁₀,-methoxy groups at C₆ and C₁₅, an -glycol system at C₇ and C₈, and a methoxy group at C₁₉.Institute of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 389–395, May–June, 1975.     

Oxygenated acids of the reserve lipids of Rumex paulsenianus

The composition of the fatty mono- and dihydroxy acids of the fruit ofRumex paulsenianus Rech. fil. (familyPolygonaceae) has been determined by a combination of IRS, UVS, GLC, and mass-spectrometric methods. (22) Monohydroxy acids of the C₁₄–C₂₀ series, including isomers and isologues, and four dihydroxy acids from C₁₈ to C₂₀, including a new isomeric 9-OH-10, 12–17:2 acid have been detected.Institute of the Chemistry of Plant Substances, Uzbek Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 762–765, November–December, 1991.     

Monte Carlo Studies of the Structural and Thermodynamic Properties of Some Smectic and Ferroelectric Liquid Crystals

Monte Carlo simulation based on the Gaussian overlap model was used to study the thermodynamic properties of smectic C: C₅H₁₁O–(OH)C₆H₃–CH=N–C₆H₄–C₅H₁₁ (A), C₁₀H₂₁O–C₆H₄–CH=CH–C₆H₄–OC₁₀H₂₁ (B), ferroelectric smectic C* liquid crystals (LC): C₇H₁₅O–C₆H₄–C₆H₄–COO–CH₂C*H(CH₃)C₂H₅ (C), C₈H₁₇O–C₆H₄–C₆H₄–C₂H₄C*H(CH₃)C₂H₅ (D), and an equimolar mixture of {A+C} and {A+D}. A system of N = 125 pairwise interacting ellipsoids of revolution placed in a volume V at a temperature T (that is, a system described by a canonical NVT-ensemble) is considered. These interactions were calculated using a specially devised Lennard-Jones potential, allowing for both mild anisotropic repulsion of particles (ellipsoids) and their dispersion attraction. Dipole–dipole interactions were also taken into account, since the molecules have highly polar groups: –O–, OH, CH=N, and COO and hence a high dipole moment (4.2-5.3 D). Calculations were carried out for a rectangular parallelepiped with periodic boundary conditions imposed on its faces. An elementary object of the NVT-ensemble was a two-molecule microcluster (dimer) but not a single molecule from the group under study. Smectic A ordering in the system has been unambiguously proven for different temperatures and fixed densities (0.32 0.44, where is the close packing coefficient). The ordering is attributed to the large (transverse) dipole moment inherent in molecules {A}-{D}. Temperature dependences of free energy, configuration energy, heat capacity C_v, and orientational order parameter were obtained. The curves agree well with the experimental data on variation of the properties of smectic LC.     

Limitations of low resolution mass spectrometry in the electron capture negative ionization mode for the analysis of short- and medium-chain chlorinated paraffins

The analysis of complex mixtures of chlorinated paraffins (CPs) with short (SCCPs, C₁₀–C₁₃) and medium (MCCPs, C₁₄–C₁₇) chain lengths can be disturbed by mass overlap, if low resolution mass spectrometry (LRMS) in the electron capture negative ionization mode is employed. This is caused by CP congeners with the same nominal mass, but with five carbon atoms more and two chlorine atoms less; for example C₁₁H₁₇³⁷Cl³⁵Cl₆ (m/z 395.9) and C₁₆H₂₉³⁵Cl₅ (m/z 396.1). This can lead to an overestimation of congener group quantity and/or of total CP concentration. The magnitude of this interference was studied by evaluating the change after mixing a SCCP standard and a MCCP standard 1+1 (S+MCCP mixture) and comparing it to the single standards. A quantification of the less abundant C₁₆ and C₁₇ congeners present in the MCCP standard was not possible due to interference from the major C₁₁ and C₁₂ congeners in the SCCPs. Also, signals for SCCPs (C₁₀–C₁₂) with nine and ten chlorine atoms were mimicked by MCCPs (C₁₅–C₁₇) with seven and eight chlorine atoms (for instance C₁₀H₁₂Cl₁₀ by C₁₅H₂₄Cl₈). A similar observation was made for signals from C₁₅–C₁₇ CPs with four and five chlorine atoms resulting from SCCPs (C₁₀–C₁₂) with six and seven chlorine atoms (such as C₁₅H₂₈Cl₄ by C₁₀H₁₆Cl₆) in the S+MCCP mixture. It could be shown that the quantification of the most abundant congeners (C₁₁–C₁₄) is not affected by any interference. The determination of C₁₀ and C₁₅ congeners is partly disturbed, but this can be detected by investigating isotope ratios, retention time ranges and the shapes of the CP signals. Also, lower chlorinated compounds forming [M+Cl]^– as the most abundant ion instead of [M-Cl]^– are especially sensitive to systematic errors caused by superposition of ions of different composition and the same nominal mass.     

Nonglyceride lipids of the seed coats ofArtemisia absinthium andOnopordum acanthium

The seed coats ofArtemisia absinthium andOnoporum acanthium have been shown to contain paraffinic hydrocarbons (C₃₁-C₂₅ and C₃₁-C₂₇, respectively), wax esters (C₃₂-C₂₃ and C₅₁-C₃₃), acetyltriterpenols (six types, five types), and acyltriterpenols with a predominance of palmitoyltriterpenols (esters of higher saturated unbranched C_32:0-C_12:0 fatty acids and triterpenols with a molecular weight of 426 belonging to the ursene group).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 154–157, March–April, 1981.     

The isocoumarin artemidinal from Artemisia dracunculus

Summary Artemidinal, C₁₀H₆O₃, which is isocoumarin with an aldehyde group at C₃, has been isolated from the epigeal part ofArtemisia dracunculus.Order of the Red Banner of Labor Institute of the Chemistry of Plant Substances of the Academy of Sciences of the Uzbek SSR. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 257–259, May–June, 1971.     

Use of multiphoton ionization of molecules for the determination of neptunium traces in solution

The possibility of detecting trace amounts of neptunium atoms and molecular compounds by laser resonance ionization spectroscopy has been investigated in acetylene-air and acetylene-nitrous oxide flames. Experimentally evaluated atomization coefficients of neptunium in the process of thermal dissociation in flames (10^–4% for C₂H₂-air and 10^–2% for C₂H₂–N₂O) do not allow to use atomic ionization signal for determination of neptunium microamounts in solutions. High yield multiphoton ionization of NpO molecule has been realized in fuel rich C₂H₂–N₂O flame. This pehnomenon has been used for determination of trace quantities of Np in solution. The detection limit was 2·10^–9 g/ml.     

Annealing Temperature Dependence of the Size of C60 Clusters in C60-Doped Silicon Oxide Films

C₆₀-doped silicon oxide thin films were prepared by spin-coating a viscous solution formed upon soaking at 40°C an acidic toluene/ethanol solution of C₆₀, phenyltriethoxysilane, and tetraethoxysilane with a C₆₀–to–Si molar ratio of 2.5 × 10^–3. The films were submitted to annealing at 300–500°C in Ar to investigate variation in the size of C₆₀ clusters embedded in the films by photoluminescence spectroscopy. The film before annealing was found to contain the clusters consisting of ca. 60 C₆₀ molecules, suggesting that C₆₀ is present well-dispersed in the film. The molecules in the film aggregated to increase the size with increasing annealing temperature, indicating that the molecules diffuse easily in the film upon heating and therefore the size of the clusters is controllable with the annealing temperature.     

1H NMR studies on intermolecular association of amphiphilic cationic polyelectrolyte micelles induced by hydrophobic counteranions in water

Interactions of a series of amphiphilic cationic polyelectrolytes with various kinds of organic counteranions have been investigated in water by one- and two-dimensional ¹H NMR spectroscopy at 20 °C. The cationic polyelectrolytes were prepared by micellar homopolymerization of tail-type cationic surface-active monomers with a cationic charge with -end, (ST–C_m–AB, m=5, 7, and 9, where ST is a styrenic group, C_m, an alkylene chain at the 4-position of styrene, and AB, alkyltrimethylammonium bromide). Aliphatic monosodium salt of maleic acid (MAS) and its stereoisomer, fumaric acid (FAS), sodium benzoate (NaB), potassium hydrogen phthalate (PHK), and sodium salicylate (NaSal) were added to a salt-free aqueous solution of the polyelectrolytes and ¹H NMR measurements were carried out. Amphiphilic P(ST–C_m–AB) polyelectrolytes act as efficient hosts to strongly capture the hydrophobic counteranions B^–, PH^–, and Sal^–, but not MA^– and FA^–. The ¹H NMR signals of these hydrophobic counteranions remarkably shift upfield and broaden in water in the presence of the amphiphilic polyelectrolytes. The nuclear Overhauser effect (NOE) signals between the cationic group of the polymer and aromatic benzoate counteranion protons are clearly observed to imply cation– interaction. The capturing of hydrophobic counterions by the polyelectrolytes is likely due to electrostatic, hydrophobic, and cation– interactions between them. The reduced viscosity, _sp/C_p, for the solution at [PHK]/[P(ST–C₇–AB)]=1.0 steeply increases with increasing polymer concentration (C_p) above ca. 0.9 g/dL to show pronounced viscoelasticity.     

Circular dichroism of some carotanes

The circular dichroism method has been used to study the stereochemistry of the carotanes. An analysis of the results obtained has shown that an -oriented ester group at C₆ corresponds to a positive Cotton effect (CE) in the 240–260-nm region. A link has been established between the position of the carbonyl group in the ring B and the sign of a CE in the 340-nm region. Hydrolysis of an ester group at C₆ takes place more readily in an alkaline medium than in an acid medium, and in the case of carbonyl-containing carotanes dehydration takes place as well as hydrolysis.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 45–48, January–February, 1984.