Oxidation of triterpenes derived from 18-lupene and 18,19-secolupane with ruthenium tetroxide by an improved procedure

A convenient preparative procedure for the oxidation with ruthernium tetroxide of 18-lupene derivatives to 18,19-secolupane-18,19-dione derivatives in an ethyl acetate-water system has been developed. It has been found that 3,28-diacetoxy-18,19-secolupane-18,19-dione can be obtained from its 19-(ethylene acetal) or 19-oxime by reaction with ruthenium tetroxide.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 655–664, September–October, 1989.     

Oxidation of betulin,dihydrobetulin, and 3β-28-dihydroxy-18-lupene by ruthenium tetraoxide

Pacific Ocean Institute of Biorganic Chemistry, Far-Eastern Branch, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 430–431, May–June, 1991.     

Oxidation reaction of steroid alcohols by ruthenium tetroxide

Oxidation of steroid alcohols by ruthenium tetroxide gives corresponding ketones in almost quantitative yields. The reaction provides a simple and convenient procedure for converting secondary alcohols to ketones in neutral media. The reconversion of ruthenium dioxide, produced during the oxidation, into the tetroxide with an appropriate oxygen donor such as sodium metaperiodate makes possible the oxidation of a given steroid alcohol to a ketone in the presence of a catalytic amount of ruthenium tetroxide.     

Interaction of hydrogen fluoride with ruthenium tetroxide

In the course of the studies concerning hydrolysis of ruthenium fluorides and fluorination of ruthenium hydroxides, we frequently noticed the formation of a volatile substance which showed a strong absorption band at 1030 cm^?1. We pursued this unknown substance and found that it was an adduct between ruthenium tetroxide and hydrogen fluoride:

This new adduct, RuO₄(HF)₁₀, is observable at temperature higher than 0°C and at HF pressure greater than 150 mmHg. Between 4000 and 200 cm^?1, the adduct shows two absorption bands—1030 cm^?1 and 389 cm^?1. At 0°C, the adduct in the gas-phase disappears for condensation.On the basis of these results, credibility of the earlier literature on RuF₈ was discussed.     

19-nor-11-Oxooleanan-12-ene and 18,19-seco-19-oxours-11,13(18)-diene triterpenes from Diospyros decandra bark

Four new triterpenes, 2α,3β-dihydroxy-19-nor-11-oxo-20-dimethylurs-12-en-24,28-dioic acid (equivalent to 2α,3β-dihydroxy-19-nor-11-oxoolean-12-en-24,28-dioic acid), 2α,3β-dihydroxy-18,19-seco-19-oxours-11,13(18)-dien-24,28-dioic acid, 2α,3β,19α-trihydroxy-11-oxours-12-en-24,28-dioic acid and 2α,3β,19α-trihydroxy-28-1′-β-d-[glucopyranosyl-(1″→6′)-glucopyranosyl]-urs-12-en-24,28-dioic acid were isolated from the methanol extract of the bark of Diospyros decandra as their acetate-methyl ester derivatives. The first two compounds represent the biosynthetic transformation products of 2α,3β,19-trihydroxyurs-24,28-dioic acid via oxidative rearrangement of ring E.     

Oxidative cleavage of 3β-acetoxy-21-oxolup-18-en-28-oic acid by ruthenium tetroxide

3β-Acetoxy-21-oxolup-18-en-28-oic acid was used as a starting compound for oxidative cleavage by ruthenium tetroxide generated in situ from ruthenium dioxide by sodium metaperiodate in a biphasic system. Tricyclic and tetracyclic acids of baccharane type were prepared by this reaction, and their structures were confirmed using spectral data. These acids were further used for synthesis of appropriate methyl and acetoxymethyl esters. All prepared compounds were tested on cytotoxic activity against CEM tumor cell line, and several compounds showed activity in low micromolar concentrations.     

Insights into coal structure from degradation with ruthenium tetroxide and tandem mass spectrometry

The products of ruthenium tetroxid oxidation of coal (Illinois No. 2) at ambient temperature were examined by tandem mass spectrometry using positive and negative chemical ionization. The negative-ion mass spectrum of the coal sample displays seven homologous series of ions. Individual compounds were characterized by recording daughter spectra. In this way, the following types of compounds were identified: aliphatic dicarboxylic acids, aromatic dicarboxylic and tricarboxylic acids, anhydrides of the di- and tri-carboxylic acids, and dianhydrides corresponding to the tetracarboxylic aromatic acids. The positive-ion mass and daughter spectra provided additional confirmation. Two series of ions dominate the positive-ion mass spectrum, those from the aliphatic dicarboxylic acids, and the corresponding anhydrides. The fragmentation behavior of model compounds was examined to confirm these assignments. The carboxylic acids and anhydrides identified suggest the presence of particular structural features in the coal prior to oxidation. These include C₂–C₆ aliphatic bridges between aromatic units, fused ring aromatic structures, tetralin and indan structures.     

Filtration tests of gaseous ruthenium tetroxide by sand bed and metallic filters

Journal of Radioanalytical and Nuclear Chemistry - This work presents laboratory tests on gaseous RuO4 filtration carried out at IRSN in Cadarache. The objective is to determine if gaseous...     

Oxidation of cyclopropane terpenoids with ruthenium tetraoxide

Oxidation products of cyclopropanoid terpenes, (-)-carane (4), (+)-cyclosativene (5), laurinterol methyl ether (6), and thujopsane (7), with ruthenium tetraoxide were investigated.     

Oxidation of selenite by alkaline ferricyanide using osmium tetroxide as a catalyst

Summary Oxidation of selenite to selenate by alkaline ferricyanide catalysed by osmium tetroxide was followed by direct and indirect procedures. Either the ferrocyanide was titrated with selenite solution at 8–10% overall alkalinity or vice versa using amperometric or potentiometric end point. In the indirect procedure the excess ferricyanide was determined by amperometric titration with arsenious oxide at 10–15% alkalinity, and the ferrocyanide with ceric sulphate using o-phenanthroline or amperometric indicator. A cerimetric determination of ferricyanide based on this reaction is described.Sincere thanks of the authors are due to Dr. S. S. Joshi, D. Sc. (London), for kind interest in the work.     

Kinetics and mechanism of ruthenium tetroxide catalysed oxidation of cyclic alcohols by bromate in a base

Summary Kinetic investigations on the RuO₄-catalysed oxidation of cyclopentanol (Cypol) and cyclohexanol (Cyhol) in alkaline KBrO₃ in the presence of Hg(OAc)₂ which acts as a bromide ion scavenger have been made in the 30°–45°C range. The reaction exhibits zero order kinetics in OH^– and is first order with respect to BrO ₃ ^– , substrate and RuO₄. The influence of Hg(OAc)₂ and ionic strength is insignificant. A transient complex, formed between HRuO ₅ ^– (the active species of RuO₄) and the cyclic alcohol, reacts with BrO ₃ ^– in a slow, rate determining step to give the products; the catalyst is regenerated.     

Oxidation of alcohols with allyl methyl carbonate by means of ruthenium catalyst

Ruthenium-catalyzed reaction of secondary or allylic alcohols with allyl methyl carbonate gives ketones or α,β-unsaturated aldehydes.     

Hydride complexes of ruthenium derived from the heterolytic activation of dihydrogen by amidophosphine complexes

The reaction of 〚NPNH〛Ru(η³:η²-cyclooctadienyl) (1) (where 〚NPNH〛 = {PhNHSiMe₂CH₂P(Ph)CH₂SiMe₂NPh}), an organometallic mono-amide complex of ruthenium(II), with hydrogen gas (1–4 atm) generates three ruthenium hydride species: 〚NPNH〛RuH (2), 〚NPNH₂〛RuH₂(C₇H₈) (3) and 〚NPNH₂〛RuH₂ (4). All of these complexes result from hydrogenation of the cyclooctadienyl group; complexes 3 and 4 also undergo conversion of the amido linkage into a ruthenium hydride and an amine. Complexes 2 and 3 have been characterized both in solution by NMR spectroscopy and in the solid state by X-ray Diffraction and Infrared Spectroscopy. While 4 was fully characterized in solution by NMR spectroscopy, attempts to recrystallize this material yielded 2; the reaction of 2 with H₂ does not produce 4. The starting complex 1 acts as a catalyst precursor for the hydrogenation of imines such as benzylidene aniline; however, none of the isolated hydride species 2, 3 or 4 were active as catalyst precursors.     

Oxidation of primary alcohols to aldehydes catalyzed by ruthenium compounds

The RuCl₃ and RuO₂·nH₂O catalyzed oxidation of alkanes, aromatic fatty acids, alcohols, citronellol, and hydroxycitronellol by NaOCl was studied in the diphase system CCl₄-aqueous NaOCl at pH 13–13.5. At 60–65°C, using 1–2 mole % of catalyst and a 1.5-fold molar excess of NaOCl, primary alkanols (hexanol-1, 2-ethylhexanol-1, decanol-1, hexadecanol-1) benzyl and 3-phenyl-propyl alcohols, and hydroxycitronellol are converted to the corresponding aldehydes with a selectivity of 70–90% and a yield of over 75%.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 115–121, January, 1991.     

An improved method for ruthenium analysis separation from uranium by pressure precipitation with H2S

Summary Pressure precipitation of ruthenium with hydrogen sulphide is recommended for its separation from uranium. The separations from uranium solutions and from pitchblende are described as examples.

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Zusammenfassung Zur Abtrennung des Rutheniums von Uran wird die Fällung mit Schwefelwasserstoff unter Druck empfohlen. Als Beispiele werden die Abtrennung aus Uranlösungen sowie aus einem Uranmineral (Pechblende) beschrieben.

     

Complexes of platinum,rhodium, iridium and ruthenium with a thiosemicarbazone derived from thiophene-2-carboxaldehyde

Summary Complexes of thiophene-2-carboxaldehyde thiosemicarbazone with Ru^III, Rh^III, Ir^III and Pt^IV have been prepared and characterized by elemental analyses, molar conductance, room temperature, magnetic moments, infrared and electronic spectral studies. Probable structures for the complexes are suggested. All are diamagnetic except the Ru^III complexes and possess octahedral structures. The crystal field parameters of the complexes have also been calculated.