Phosphorylation of emodin

A convenient method has been developed for the interaction of dialkyl phosphites with 1,6,8-trihydroxy-3-methylanthraquinone (emodin) under the conditions of the Todd—Atherton reaction. It has been shown that the α-hydroxy groups of emodin are not phosphorylated at an equimolar ratio of emodin and dialkyl phosphite. The phosphorylation of 7-bromo-1,6,8-trihydroxy-3-methylanthraquinone with potassium dialkyl phosphorothioates has been studied. The reaction takes place at the sulfur atom, with the formation of of the product of S-alkylation.     

Bromination of emodin

Using emodin as an example, it has been shown that in the bromination of hydroxyanthraquinones the qualitative composition and quantitative ratio of the reaction products depend on the nature of the brominating agent and the solvent, the ratio of the rea Lants, and the temperature regime. In order to obtain bromo-3-methyl-1,6,8-trihydroxyanthraquinone it is recommended to use dioxane dibromide in acid solution as the brominating agent, and to obtain 5-bromo-3-methyl-1,6,8-trihydroxyanthraquinone the same reagent in dioxane solution. The optimum conditions for obtaining 3-bromomethyl-1,6,8-trihydroxyanthraquinone by the methods of initiated bromination and photobromination have been selected.S. M. Kirov Kazakh State University, Alma-Ata. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 618–621, September–October, 1990.     

Anthraquinone pigments from the crinoid Comanthus bennetti

From the crinoid Comanthus bennetti we isolated and characterized five pigments. One is the known 3-(1′-hydroxypropyl)-1,6,8-trihydroxy-9,10-anthraquinone (rhodoptilometrin). The remaining four had not previously been isolated from a natural source: 3-propyl-1,6,8-trihydroxy- 9,10-anthraquinone; 3-propionyl-1,6,8-trihydroxy-9,10-anthraquinone; 3(2′-hydroxypentyl)-1,6,8- trihydroxy-9,10-anthraquinone; and 2-(1′-hydroxypropyl)-1,4,5,7-tetrahydroxy-9,10-anthraquinone.     

Analysis of anthraquinones in Rumex crispus by micellar electrokinetic chromatography

A micellar electrochromatographic method was performed for the analysis of the pharmaceutically important anthraquinones from the root of Rumex crispus. The separation of 1,5-dihydroxy-3-methylanthraquinone (1); 1,3,5-trihydroxy-6-hydroxymethylanthraquinone (2); 1,5-dihydroxy-3-methoxy-7-methylanthraquinone (3) was achieved in 6 min using a running buffer containing 10 mmol/l sodium borate, 50 mmol/l sodium dodecylsulfate, and 25% acetonitrile at pH 10.6. The method is simple, rapid, and reproducible.     

Reaction of frangula-emodin with <Emphasis Type="Italic">α</Emphasis>-bromoalkylmethylketones

The alkylation of 1,6,8-trihydroxy-3-methylanthraquinone (frangula-emodin) by α-bromoalkylmethylketones was investigated. Hydroxyls in the 1-and 8-positions of the β-derivatives were O-acylated. The compositions and structures of the prepared compounds were confirmed by elemental analysis and UV, IR, PMR, and ¹³C NMR spectroscopy. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 324–326, July–August, 2007.     

An thraquin one pigments of the starfish Echinaster echinophorus. IV

Summary 1. Anthraquinone pigments forming derivatives of 1,6,8-trihydroxy-9,10-anthraquinone have been found in the starfishEchinaster echinophorus (Lamarck).2. The structures of the pigments isolated are identical with those of pigments of sea lilies.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center of the Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 636–640, September–October, 1977.     

Bromination of emodin

Using emodin as an example, it has been shown that in the bromination of hydroxyanthraquinones the qualitative composition and quantitative ratio of the reaction products depend on the nature of the brominating agent and the solvent, the ratio of the rea Lants, and the temperature regime. In order to obtain bromo-3-methyl-1,6,8-trihydroxyanthraquinone it is recommended to use dioxane dibromide in acid solution as the brominating agent, and to obtain 5-bromo-3-methyl-1,6,8-trihydroxyanthraquinone the same reagent in dioxane solution. The optimum conditions for obtaining 3-bromomethyl-1,6,8-trihydroxyanthraquinone by the methods of initiated bromination and photobromination have been selected. S. M. Kirov Kazakh State University, Alma-Ata. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 618–621, September–October, 1990.     

Structure of mucrolidin. Analysis of the influence of some oxygen-containing substituents on the chemical shifts of the protons of the angular methyl of sesquiterpenoids with the eudesmane type of skeleton

A new eudesmanol, mucrolidin has been isolated from the epigeal part of Tanacetopsis mucronata. Its IR, mass, and PMR spectral characteristics have been investigated. Its composition has been established unambiguously by x-ray structural analysis and its spatial structure as 1,4,6-trihydroxy-1, 5, 6, 7(H)-eudesmane. The interrelationship of the mucrolidin molecules in cyrstal packing is considered. With this sesquiterpenoid as an example, and using the characteristics of the PMR spectra of related compounds, the influence of some oxygen-containing functional groups at C-1, C-4, and C-6 on the chemical shifts of the protons of the methyl at C-10 has been analyzed.Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 320–326, May–June, 1998.     

Crystal and molecular structures of the alkaloid verdine

An x-ray structural analysis has been made with the object of reliably determining the structure of the alkaloid verdine. The position of the hydroxy group, not determined by other methods has been found and it has been established that the alkaloid verdine has the structure and configuration of 1,3,6-trihydroxy-5-jervanin-12-en-11-one.Institute of the Chemistry of Plant Substances, Academy of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 753–758, November–December, 1984.     

Structure of tetraphenylarsonium tricyano- 2,2′,6′,2′′-terpyridylferrate(II), AsPh4[FeII(terpy)(CN)3]; and kinetics of oxidation of the complex anion by peroxodisulfate in water and in binary aqueous mixtures

The structure of the title compound has been determined by X-ray crystallography. The octahedral arrangement of ligands about the iron(II) centre is somewhat distorted, with the axial NC–Fe–CN bond angle being 174.3(4)°. The oxidation of the tricyano-2,2,6,2- terpyridylferrate(II) anion by the peroxodisulfate anion has been investigated in water and in binary aqueous mixtures. The reaction follows a second order rate law, with a second-order rate constant of 0.126± 0.001dm3mol–1s–1 at 295.2K. The enthalpy and entropy of activation in water are 51.3±1.8kJmol–1 and –89±5JK–1mol–1 respectively. The rate is retarded on addition of organic cosolvent. The transfer chemical potential of the initial state from water into mixed solvents has been determined from solubility measurements, and compared with the transfer potential of the transition state. Solvent effects on the reaction are discussed in terms of initial state versus transition state solvation.     

Arenobufagin and gamabufotalin from the venom of the Central Asian green toadBufo viridis. Introduction,structural—functional features

Two bufodienolides have been isolated in the individual form from the Central Asian green toadBufo viridis for the first time. It has been established by₁H NMR, mass spectrometry, and x-ray structural analysis that these compounds are gamabufotalin (3, 11, 14-trihydroxy-5, 14ß-bufa-20,22-dienolide) and a crystalline modification of arenobufagin (3, 11, 14-trihydroxy-12-oxo-5, 14-bufa-20,22-dienolide). The biological activity of Bakagin — the total bufadienolides of the venom ofB. viridis, consisting predominantly of the compounds named — has been studied. The promising nature of a further study of Bakagin as a cardiotonic drug has been shown.Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 260–268, March–April, 1995. Original article submitted October 10, 1994.     

Synthesis and properties ofN′-(phosphorylalkyl)diazeneN-oxides

A method has been developed for the synthesis ofN-(phosphorylalkyl)diazeneN-oxides based on the reaction of nitroso compounds with dialkyl (-aminoalkyl)phosphonates in the presence of dibromoisocyanurate. Some chemical properties of the synthesized compounds have been studied.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1290–1293, July, 1994.     

On the synthesis of ω-appended hypericin derivatives

Summary A method for the preparation ofbis--appended hypericin derivatives bearingn-octyl,n-hexadecyl, and 2-(2-(2-hydroxyethoxy)-ethoxy)-ethoxymethyl substituents was developed. The key step — the synthesis of appropriately -substituted emodin derivatives — was achieved by solvolyzing 3-bromomethyl-1,6,8-triacetyloxy-anthracene-9,10-dione (-bromo triacetylemodin) in an appropriate alcohol in the presence of silver perchlorate. The correspondingbis--substituted hypericins were then prepared conventionally by dimerizing the -substituted emodin anthrones. The latter were prepared by reduction of the -appended emodins.

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Zur Synthese von -substituierten Hypericinderivaten

Zusammenfassung Eine Methode zur Darstellung vonbis--substituierten Hypericinderivaten wurde entwickelt. Der Schlüsselschritt — die Synthese der entsprechenden Emodinderivate — wurde durch die Solvolyse von 3-Bromomethyl-1,6,8-triacetyloxyanthracen-9,10-dion (-Bromtriacetylemodin) im entsprechenden Alkohol in Gegenwart von Silberperchlorat ermöglicht. Die entsprechendenbis--substituierten Hypericinderivate wurden auf konventionelle Weise durch Dimerisierung der -substituierten Emodinanthrone dargestellt. Letztere erhielt man durch Reduktion der -substituierten Emodine.

     

Quantitative determination of organic peroxides

A method has been developed for the analysis of several important dialkyl peroxides. It involves the use of high-performance liquid chromatography (HPLC) in reversed-phase mode, with a mixture of methanol and water as the mobile phase. The assurance and sensitivity limits for each of the peroxides are given. The proposed method is fast and simple with good precision. The relative standard deviations are in the range of 1.1–3.7% for 0.01–19.2 g of peroxide per mL.     

Spectral characteristics of C-methylflavones

A study has been made of natural C-methylflavones and their dealkylated analogues: 5-hydroxy-4,7-dimethoxy-7-methylflavone (noreucalyptin); 4,5,7-trihydroxy-6-methylflavone; 5-hydroxy-4,7-dimethoxy-6,8-dimethylflavone (eucalyptin); 4,5-dihydroxy-7-methoxy-6,8-dimethylflavone (sideroxylin); 4,5,7-trihydroxy-6,8-dimethylflavone; 4,5,6-trihydroxy-3-methoxy-8-methylflavone (silpin) and 3,4,5,6-tetrahydroxy-8-methylflavone.All-Union Scientific-Research Institute of Medicinal Plants, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 306–309, May–June, 1984.     

Ab initio calculations of potential energy surface for reaction of nucleophilic addition of H− ion to methylacetylene

Within the framework of the Hartree-Fock-Roothaan Method, using double- basis sets 3-21++G and (6-31-H-G//3-21++G), the minimum energy paths (MEPs) have been calculated for reactions of nucleophilic addition of the hydride ion H^– to the methylacetylene molecule: CH₃-CCH+H^–[CH₃-CH=CH]^– (1) CH₃-CCH+H^–[CH₃-C=CH₂]^– (2). It has been established that the activation energy for reaction (2) is 7.02 kJ/mole lower than for reaction (1). An analysis has been made of the character of electron density distribution along the MEP of each reaction. It has been shown that distortion of geometry of the reactants plays an important role in intensifying the interaction of the frontier orbitals. The reasons for nonfulfillment of Markownikoff's rule for these reactions have been determined. The results from the calculations are compared with calculations reported in the literature for the related reaction of nucleophilic addition of the hydride ion H^– to the acetylene molecule: HCCH+H^–[CH₂=CH]^–.Translated from Teoreticheskaya i Éxperimental'naya Khimiya, Vol. 21, No. 3, pp. 303–309, May–June, 1985.     

Crystal and molecular structures of the sesquiterpene lactone ajafinin

An x-ray structural analysis has been made with the aim of reliably determining the spatial structure of the sesquiterpene lactone ajafinin. It has been established that it has the structure and configuration of 1,2--epoxy-3,4,10-trihydroxy-5,6(H),7(H)-guai-11(13)-en-6,12-olide.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 291–295, May–June, 1986.