Investigation of the products of the ozonolysis of larixol

On the ozonization of larixol in methanol followed by treatment with ammonium chloride, the main reaction products were 15,16,20-trisnorlabd-6-ene-8,13-dione and 6-hydroxy-8,13;8,14-diepoxy-15,20-bisnorlabd-14-one. When ozonization was performed in methanol in the presence of dimethyl sulfide or in methylene chloride in the presence of pyridine, 6,14-dihydroxy-8,13;8,14-diepoxy-15,20-bisnorlabdane and 6-hydroxy-14,50,20-trisnorlabd-8,13-dione predominated in the reaction products.Institute of Chemistry of the MSSR Academy of Sciences, Kishinev, and Institute of Organic Chemistry of the Bashkir Branch of the USSR Academy of Sciences, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 577–584, September–October, 1986.     

Investigation of the products of the ozonolysis of larixol

On the ozonization of larixol in methanol followed by treatment with ammonium chloride, the main reaction products were 15,16,20-trisnorlabd-6-ene-8,13-dione and 6-hydroxy-8,13;8,14-diepoxy-15,20-bisnorlabd-14-one. When ozonization was performed in methanol in the presence of dimethyl sulfide or in methylene chloride in the presence of pyridine, 6,14-dihydroxy-8,13;8,14-diepoxy-15,20-bisnorlabdane and 6-hydroxy-14,50,20-trisnorlabd-8,13-dione predominated in the reaction products.     

A new approach to the furan degradation problem involving ozonolysis of the trans-enedione and its use in a cost-effective synthesis of eplerenone

[reaction: see text] Whereas ozonization of furan 3a affords little or no carboxylic acid 5, ozonization of the corresponding trans-enedione 6 afforded carboxylic acid 5 in 82.4% yield (cryst., overall from furan, 100 g scale; after workup with dimethyl sulfide, followed by mildly basic hydrogen peroxide). This new approach to furan degradation is showcased in a cost-effective synthesis of eplerenone, an important new medicine for cardiovascular indications.     

Investigation of the structural peculiarities and chemical transformations of carbazole and its derivatives

A method for the synthesis of thioethers of the carbazole series by the reduction of 3-thiocyanato- and 3,6-dithiocyanatocarbazoles with sodium sulfide and subseqent condensation of the reduction products with alkyl halides is described.See [1] for communication XXXV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1076–1077, August, 1971.     

臭氧化法在高分子生物材料表面改性中的应用

综述了臭氧化法在高分子生物材料表面改性中的应用及研究，介绍了臭氧化法的特点，过氧化物浓度的测定及臭氧化反应和过氧化物引发接枝共聚的反应机理。     

A new route to the stereospecific synthesis of terpenoid 1,5-polyenes via isoprene cyclooligomers

Conclusions We have suggested a new route to the stereospecific synthesis of terpenoid 1,5-poIyenes via the products of selective ozonization of isoprene cyclooligomers.For preliminary communication see [1]Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 887–889, April, 1978.     

Silver nanoparticle assemblies supported on glassy-carbon electrodes for the electro-analytical detection of hydrogen peroxide

Electrochemical detection of hydrogen peroxide using an edge-plane pyrolytic-graphite electrode (EPPG), a glassy carbon (GC) electrode, and a silver nanoparticle-modified GC electrode is reported. It is shown, in phosphate buffer (0.05 mol L^–1, pH 7.4), that hydrogen peroxide cannot be detected directly on either the EPPG or GC electrodes. However, reduction can be facilitated by modification of the glassy-carbon surface with nanosized silver assemblies. The optimum conditions for modification of the GC electrode with silver nanoparticles were found to be deposition for 1 min at –0.5 V vs. Ag from 5 mmol L^–1 AgNO₃/0.1 mol L^–1 TBAP/MeCN, followed by stripping for 2 min at +0.5 V vs. Ag in the same solution. A wave, due to the reduction of hydrogen peroxide on the silver nanoparticles is observed at –0.68 V vs. SCE. The limit of detection for this modified nanosilver electrode was 2.0×10^–6 mol L^–1 for hydrogen peroxide in phosphate buffer (0.05 mol L^–1, pH 7.4) with a sensitivity which is five times higher than that observed at a silver macro-electrode. Also observed is a shoulder on the voltammetric wave corresponding to the reduction of oxygen, which is produced by silver-catalysed chemical decomposition of hydrogen peroxide to water and oxygen then oxygen reduction at the surface of the glassy-carbon electrode.     

Formation of hydrotrioxides in the low-temperature ozonization of aliphatic ketones

Conclusions The ozonization of 2-butanone and 2-hexanone at from –70°C to –60°C leads to the corresponding hydrotrioxides, which undergo first-order thermal decomposition accompanied by intense chemiluminescence in the visible and IR regions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1660–1662, July, 1985.     

One-step synthesis of carbon-supported Pd–Pt alloy electrocatalysts for methanol tolerant oxygen reduction

A facile, one-step reduction route was developed to synthesize Pd-rich carbon-supported Pd–Pt alloy electrocatalysts of different Pd/Pt atomic ratios. As-prepared Pd–Pt/C catalysts exhibit a single phase fcc structure and an expansion lattice parameter. Comparison of the oxygen reduction reaction (ORR) on the Pd–Pt/C alloy catalysts indicates that the Pd₃Pt₁/C bimetallic catalyst exhibits the highest ORR activity among all the Pd–Pt alloy catalysts and shows a comparative ORR activity with the commercial Pt/C catalyst. Moreover, all the Pd–Pt alloy catalysts exhibited much higher methanol tolerance during the ORR than the commercial Pt/C catalyst. High methanol tolerance of the Pd–Pt alloy catalysts could be attributed to the weak adsorption of methanol induced by the composition effect, to the presence of Pd atoms and to the formation of Pd-based alloys.     

Kinetics of the Oxidation of Methyl Phenyl Sulfide by Hydrogen Peroxide in the Presence of Hydrocarbonate Anion

The oxidation of methyl phenyl sulfide in water and water-alcohol mixtures takes place both by a noncatalytic mechanism and with the participation of hydrogen peroxide as catalyst; in the presence of ammonium hydrocarbonate it takes place by a mechanism involving HCO ₄ ⁻ as a more active oxidant than hydrogen peroxide (>100 times). In water-alcohol media (ethylene glycol, isopropyl alcohol, tert-butanol) the rate decreases in the order H₂O > EG > IPA > TBA. The reactivity of organic sulfides varies in the following way: MeSPh ≈ EtSPh << Et₂S. The results were interpreted from the standpoint of a molecular mechanism of oxidation of the sulfide with H₂O₂ and HCO ₄ ⁻ through a polar transition state, containing the HOX molecule (X = H, OH, OR) as acid-base catalyst.__________Translated from Teoreticheskaya i Eksperimental’naya Khimiya, Vol. 41, No. 2, pp. 94–99, March–April, 2005.     

Catalysis of the Sodium Sulfide Reduction of Methylviologene by CuS Nanoparticles

Feasibility was demonstrated for the catalysis of the sodium sulfide reduction of methylviologene (MV²⁺) in aqueous solution using cupric sulfide nanoparticles. The catalytic activity of the nanoparticles depends on their size. The basic features were found for the formation of the MV^+· radical–cation in the reduction of MV²⁺ by HS^– anions in the presence of CuS nanoparticles as the catalyst. This is an equilibrium reaction.     

Separation of Gold from Sulfide Using a Plasma Arc Fuming Process

Transferred-arc plasma treatment of iron sulfides containing gold is examined from both thermodynamic and experimental points of view. Three cases are analyzed: argon plasma with sulfide, argon plasma with a carbon–sulfide mixture, and argon–methane plasma with sulfide. The carboreduction of the materials appears to be well adapted for gold separation by fuming, but experimentally the process is limited by the poor mixing of graphite with molten material. The reduction with a CH₄ (10%) plasma is a proved alternative to the aforementioned process. A gold extraction efficiency of 90% is achieved for batch smelting operations.     

Synthesis and ozonization of (+)-4α-(1-trimethylsilyloxyethen-1-yl)-2-carene

(+)-4-(1-Trimethylsilyloxyethen-1-yl)-2-carene was synthesized, and the products of its ozonization were identified.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1984–1987, October, 1995.     

Oxidation of bifunctional organoboron compounds with sodium peroxide for analysis purposes

Conclusions A method was developed for the analysis of bifunctional organoboron compounds, which involved their oxidation in methanol solution with sodium peroxide, subsequent acetylation, and then gas—liquid chromatographic analysis of the obtained diacetoxyalkanes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 748–749, April, 1966     

Adsorption Interaction of Oligomeric Sebacic Acid Peroxide with Aerosil Surface and Its Thermolysis in Different Solvents

Adsorption of oligomeric sebacic acid peroxide on dispersed mineral filler (aerosil) from different solvents was studied. IR spectroscopy was used to study an effect of solvent–peroxide–aerosil adsorption interaction on the products of peroxide thermolysis. Thermodynamic quality of a solvent with respect to oligoperoxide decreases in benzene > chloroform > dimethylformamide > dioxane series. Due to competitive adsorption and the change in the conformation of oligomeric molecule, the solvent considerably affects the peroxide decomposition in the presence of aerosil.     

Photometric and Gas-Chromatographic Determination of Hydrogen Peroxide and Peroxybutanoic Acid in Oxidized Butanoic Acid

Procedures were developed for determining hydrogen peroxide and peroxy acids mixed with peroxide compounds of other classes in the oxidation products of butanoic acid with atmospheric oxygen and hydrogen peroxide. Conditions were found for the selective decomposition of hydrogen peroxide with catalase in the presence of an excess of the carboxylic acid deactivating the enzyme. The errors introduced by the acylation of hydrogen peroxide with the carboxylic acid in the course of sample treatment with the enzyme were eliminated by adding diphenyl sulfide or dimethyl sulfoxide, which selectively reduced the peroxy acids. The concentrations of hydrogen peroxide and the peroxy acid were found from the difference between the total concentration of the peroxide compounds before and after treating a sample with catalase and a sulfur-containing reagent by the photometric method using a reagent containing Fe²⁺ ions and N, N-dimethyl-p-phenylenediamine. Peroxy acids were determined by GLC from the yields of the oxidation products of diphenyl sulfide with the peroxy acid (diphenyl sulfoxide and diphenyl sulfones).     

Products of the ozonolysis of epitorulosol

The structure of the products of the ozonization of epitorulosol [13S-labda-8(20),14-diene-13,19-diol] (I) has been established. Compound (I) (1 g) was ozonized at –30°C in 100 ml of absolute CH₃OH until saturation. The O₃ was driven off by nitrogen, 1 ml of (CH₃)₂S was added at –10°C, and the mixture was stirred for 1 h each at –10, 0, and 20°C and was worked up, and the product (1.13 g) was chromatographed on a column containing 45 g of silica gel. The following were eluted in the order of increasing polarity: 420 mg of 19-hydroxy-8,13;8,14-diepoxy-13S-15,20-bisnorlabdan-14-one (II), mp 141.5–142.5°C (from petroleum ether), [] _D ²³ –63° (c 3.1); 255 mg of 8,13;8,14-diepoxy-13S-15,20-bisnorlabdane-14,19-diol (III), characterized in the form of the diacetate (IV) with mp 100–107°C (from petroleum ether); and 117 mg of 19-hydroxy-14,15,20-trisnorlabdane-8,13-dione (V), mp 82–83°C [from petroleum ether-diethyl ether (1:1)], [] _D ²⁶ –40° (c 1.7). The same products but in different ratios were formed on the ozonization of (I) in CH₂Cl₂-Py or in hexane followed by decomposition of the ozonide by heating with H₂O. The []_D values were measured in CHCl₃. Details of the IR and PMR spectra are given.Institute of Chemistry, Academy of Sciences of the Moldavian SSR, Kishinev. Institute of Organic Chemistry, Siberian Branch of the USSR Academy of Sciences, Novosibirsk. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 524–527, July–August, 1987.     

Catalysis by Hydrogen Carbonate and Silicate Anions of the Oxidation of Diethyl Sulfide with Hydrogen Peroxide in Aqueous and Aqueous–Alcoholic Media

The kinetics of the oxidation of diethyl sulfide (Et₂S) with hydrogen peroxide, catalyzed by hydrogen carbonate and silicate anions, agree with the assumption that peroxymonocarbonate (HCO^– ₄) and peroxymonosilicate (HSiO^– ₄) anions are formed as intermediates. The rate of reaction of Et₂S with HCO^– ₄ is about 100 times as fast as with H₂O₂. Transfer to aqueous–alcoholic solutions leads to an increase in the solubility of Et₂S while retaining the catalytic effects.     

Electrocatalysis of the Oxygen Reaction by Pyropolymers of N4 Complexes

Results of research into structural and electrocatalytic properties of metalloporphyrins and metallophthalocyanines pyrolyzed on carbon supports of various dispersion degree in the oxygen electroreduction reaction (OER) are analyzed. The pyrolysis products (pyropolymers) that form at T 800° in inert atmosphere contain centers Co(Fe)–N surrounded by carbon particles. The oxygen electroreduction reaction on pyropolymers in acid and alkali solutions is studied on a model gas-diffusion electrode and a rotating ring–disk electrode. The slopes of Tafel plots in an acid solution are 60 and 120 mV. On a disk electrode covered with a pyropolymer, the intermediate product of OER, hydrogen peroxide, is fixed on the ring electrode throughout the entire range of OER potentials. The activity of pyropolymers in the hydrogen peroxide electroreduction reaction in an acid solution is insignificant. In an acid environment, OER occurs via a parallel–successive mechanism with a slow stage of the attachment of the first electron. In alkali media, slopes of Tafel plots equal 40 and 120 mV at low and high polarizations, respectively. The amount of hydrogen peroxide fixed on the ring electrode corresponds to 2–5% of the disk electrode current. A pyropolymer is active in the hydrogen peroxide reduction. The slow stage in OER in an alkali environment is the attachment of the second electron at a low polarization and the attachment of the first electron, at a high polarization. In acid and alkali solutions a pyropolymer is methanol-tolerant.     

Products of the electrochemical reduction of borylphosphinoethene in a nonaqueous medium

In order to confirm our earlier assumptions with respect to the processes involved in the electrochemical reduction of borylphosphinoethene derivatives, we have analyzed the products of controlled-potential electrolysis. Compounds were isolated and identified, formed in the further chemical conversions of the initially formed unstable intermediates. It has been demonstrated that the electroreduction of the borylphosphinoethene oxide in an aprotic medium leads primarily to splitting of the P-C_Ar bond and in the case of the borylphosphinoethene selenide to the reduction of the P=Se bond; in the reduction of the corresponding sulfide both these fragments are affected.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 182–185, January, 1991.