Research on vinyl ethers of the furan series VIII. Vinyl ethers of 2-(α-furyl)ethanols

Vinyl ethers of-furyl-,-(5-methylfuryl)-,-furfuryloxy-, and-tetrahydrofurfuryl-oxyethanols were synthesized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1593–1595, December, 1971.     

H-Nuclear Magnetic Resonance and Phase Solubility Studies of the Stoichiometries in 2,4-D: α- and β-Cyclodextrins Inclusion Complexes

The interaction in solution between2,4-dichlorophenoxyacetic acid with - and-cyclodextrins was evaluated by phasesolubility studies. Association constants werecalculated by this technique. The stoichiometries were1 : 2 and 1 : 1 for the - and -cyclodextrincomplexes, respectively. In order to corroborate thecomplexation and the knowledge of structural aspectsof the host : guest interaction, proton nuclearmagnetic resonance (¹H-NMR) spectroscopy wasemployed. The application of the continuous variationtechnique corroborated the calculated complexstoichiometries by solubility assays. ComplementaryNOE studies were applied in order to corroborate theproposed complex structures.     

Thermoanalytical assessment of the quality of edible and technical oils

An investigation of the thermal decomposition of fish oils and motor lubricating oils resulted in the elaboration of a new method, which, by utilizing the relationship between the temperatures of mass losses and the changes in the cnemical composition due to the oxidative and hydrolytic decomposition of fish oils and to the processes occuring in lubricating oils in the course of their service in the oils system of combustion engines, allows estimations of the physicochemical properties of these oils.

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Zusammenfassung In Zusammenhang mit der Ausarbeitung einer neuen Methode, die die Abschätzung der physikalisch-chemischen Eigenschaften von Fischölen und Motorschmierölen ermöglicht, wurde eine Untersuchung über die thermische Zersetzung dieser Öle durchgeführt. Als Grundlage dafür diente der Zusammenhang zwischen der Masseverlusttemperatur und der mit der oxidativen bzw. hydrolytischen Zersetzung von Fischölen und den Alterungsprozessen von Motorschmierölen in Verbrennungsmotoren in Verbindung stehenden Veränderung der chemischen Zusammensetzung.

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, - , , , , .

     

Thermal decomposition of zirconyl oxalates

Conditions for the preparation of stoichiometric barium zirconyl oxalate heptahydrate (BZO) have been standardized. The thermal decomposition of BZO has been investigated employing TG, DTG and DTA techniques and chemical and gas analysis. The decomposition proceeds through four steps and is not affected much by the surrounding gas atmosphere. Both dehydration and oxalate decomposition take place in two steps. The formation of a transient intermediate containing both oxalate and carbonate groups is inferred. The decomposition of oxalate groups results in a carbonate of composition Ba₂Zr₂O₅CO₃, which decomposes between 600 and 800° and yields barium zirconate. Chemical analysis, IR spectra and X-ray powder diffraction data support the identity of the intermediate as a separate entity.

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Zusammenfassung Die Bedingungen für die Herstellung von stöchiometrischem Barium-zirconyl-oxalat Heptahydrat (BZO) wurden standardisiert. Die thermische Zersetzung von BZO wurde unter Einsatz der TG-, DTG- und DTA, sowie der chemischen und Gasanalyse untersucht. Die Zersetzung verläuft über vier Stufen und wird von der umgebenden Gasathmosphäre nicht besonders beeinflusst. Sowohl die Dehydratisierung als auch die Oxalatzersetzung erfolgt in zwei Stufen. Die Bildung einer intermediären Übergangsverbindung mit sowohl Oxalat- als auch Carbonatgruppen wirken hierbei mit. Die Zersetzung der Oxalatgruppen ergibt ein Carbonat der Zusammensetzung Ba₂Zr₂O₅CO₃, das zwischen 600 und 800° zersetzt wird und Bariumzirconat ergibt. Die Angaben der chemischen Analyse, der IR-Spekren und der Röntgen-Pulver-Diffraktion unterstützen die Identität der Intermediärverbindung als eine separate Einheit.

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Résumé On a standardisé les conditions de préparation de l'oxalate heptahydraté de zirconyle et de baryum (BZO) stoechiométrique. On a étudié la décomposition thermique de BZO par TG, TGD et ATD ainsi que par analyses chimiques et analyses des gaz. La décomposition a lieu en quatre étapes et n'est pas trop influencée par l'atmosphère ambiante. La déshydratation et la décomposition de l'oxalate ont lieu en deux étapes. Il se forme un composé intermédiaire de transition contenant à la fois les groupes oxalate et carbonate. La décomposition des groupes oxalate fournit un carbonate de composition Ba₂Zr₂O₅CO₃ qui se décompose entre 600 et 800° pour fournir du zirconate de baryum. L'analyse chimique, les spectres IR et la diffraction des rayons X sur poudre, apportent les preuves de l'existence d'un composé intermédiaire comme entité séparée.

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() . , , . . . , . Ba₂Zr₂O₅CO₃, 600–800 c . , .

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The authors express their sincere thanks to Professor A. R. Vasudevamurthy for his keen interest and constant encouragement. One of us (TG) is grateful to the Council of Scientific and Industrial Research, India, for the award of a research fellowship.     

Triterpene glycosides ofAstragalus and their genins XLV. The chemical transformation of cycloartanes 1. Synthesis of 25-norglycosides

Literature information is given on the current state of the study of the chemical transformation of cycloartane triterpenoids. A method has been developed for the transformation of the genin part of glycosides of 20,24-epoxycycloartan-25-ols with retention of the carbohydrate constituents. Three 25-norglycosides have been synthesized from natural cyclosieversigenin glycosides, namely 16-acetoxy-3,6-dihydroxy-20R,25-norcycloartan-20,24-olide 3-O-[O--L-arabinopyranosyl-(12)--D-xylopyranoside] 6-O--D-xylopyranoside (VIII), sodium 3,6,16,20-tetrahydroxy-20R,25-norcycloartan-24-oate 6-O--D-glucopyranoside 3-O--D-xylopyranoside (XII), and 20R,25-norcycloartane-3,6,16,20,24-pentaol 6-O--D-glucopyranoside 3-O--D-xylopyranoside (XIII).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 710–718, September–October, 1993.     

Quantum-chemical studies of acidic centers in aluminophosphates

In terms of the MINDO/3 method in the cluster approximation, the probable Lewis and Brönsted acidic centers of aluminophosphates have been studied.

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MINDO/3 .

     

Oxidative bromination of olefins catalyzed by thallium(III) and heteropolyacids in aqueous solutions

The system Tl^III+HPA-n, where HPA-n is the heteropolyacid H_3+nPMo_12–nV_nO₄₀ with n=2–8, in the presence of O₂ is found to be a homogeneous catalyst for the oxidative bromination of olefins by Br^– ions in aqueous solutions.

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, Tl^III+HPA-n, HPA-n — H_3+nPMo_12–nV_nO₄₀ n=2–8, O₂ Br^– .

     

Thermogravimetric and kinetic study of a clodronic acid complex formed with sodium

Thermal stability of the clodronic acid complex formed with sodium (Na₂CCl₂(HPO₃)₂ ·4H₂O) was studied using both dynamic and isothermal thermogravimetric analyses as well as mass spectra. The thermal decomposition has two stages: dehydration and loss of two molecules of hydrogen chloride. Using the isothermal TG data the first step was found to be a phase-boundary reaction while the second step obviously cannot be described with just one reaction mechanism. The final residue of the dynamic TG analyses above 810 K was found to be sodium metaphosphate.

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Zusammenfassung Sowohl mittels dynamischer und thermogravimetrischer Untersuchungen als auch and Hand von Massenspektren wurde die thermische Stabilität des mit Natrium gebildeten Säurekomplexes Na₂CCl₂(HPO₃)₂·4H₂O untersucht. Die thermische Zersetzung vollzieht sich in zwei Schritten: Dehydratation und Verlust von zwei Molekülen HCl. Auf Grund der isothermen TG Angaben ist der erste Schritt eine Phasengrenzreaktion, während der zweite Schritt mit einem einzigen Reaktionsmechanismus nicht eindeutig beschrieben werden kann. Das Endprodukt der DTG Analyse oberhalb 810 K erwies sich als Natriummethaphosphat.

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-Na₂CCl₂/HPO_3/2·4H₂O — , - . , , , . , , . 810 .

     

Formulation and Preliminary in vivo Testing of Rufloxacin-Cyclodextrin Ophthalmic Solutions

Aim of the present work was to investigate the effect of somecyclodextrins (CDs) on the solubility and ocular bioavailability of rufloxacin base (RUF), with theultimate goal of developing an ophthalmic formulation. Phase solubility studies of RUF inpH 7.4 buffer were carried out in the presence of -cyclodextrin (-CD),hydroxypropyl--cyclodextrin (HP--CD) and -cyclodextrin(-CD). The effect of hydroxypropyl methylcellulose (HPMC) on RUF solubility was evaluated after heating the solutionscontaining HP--CD at 120 °C.A significant enhancement of RUF solubility was achieved by associatingthe drug with CDs, particularly HP--CD. This CD formed with RUF a less stablecomplex than that formed by -CD, but did not suffer the solubility limitations ofthe parent CD, and showed a higher solubilizing capacity than -CD. Addition of 0.25%(w/v) HPMC to solutions containing HP--CD increased the solubilizing effect of this CD,thus allowing reduction of the amount necessary for solubilization of 0.3% (w/v) RUF.Preliminary pharmacokinetic data in rabbits indicated that theocular bioavailability of 0.3% (w/v) RUF solubilized by HP--CD was higher when compared witha 0.3% (w/v) RUF suspension used as reference.     

Steroid compounds from the Pacific starfish Lysastrosoma anthosticta

Two new steroid compounds, 3,6-dihydroxy-5-cholesta-9(11),24-dien-23-one 3-sulfate and 3,6-dihydroxy-5-cholest-9(11)-en-23-one 3-sulfate, were isolated from the Pacific starfish Lysastrosoma anthosticta as the corresponding sodium salts and identified. Two previously known glycosides of 24(S)-5-cholestane-3,6,8,15,24-pentol were also isolated and identified as sodium 24-O--d-glucopyranoside 6"-sulfate (pycnopodioside C) and sodium 24-O--d-xylopyranoside 4"-sulfate (luridoside A).     

Application of the MIMS Technique to Study the Stability Constants of Small Organic Guest Molecules into Cyclodextrin Hosts in Aqueous Medium

In this work the potential of MIMS (Membrane Introduction Mass Spectrometry) for studying the inclusion of small organic guest molecules into cyclodextrin hosts in aqueous medium was investigated. MIMS profiles showed that the inclusion of benzene in cyclodextrins is favored in the following order: -CD HO-propyl--CD> -CD> -CD with equilibrium constants of K -CD = 404; K_HO-propyl-CD = 395, K _-CD = 335 and K _-CD = 210 M^-1 at 25 °C. Kinetic experiments suggested that under the conditions employed the inclusion process has a pseudo first-order dependence on the guest benzene concentration with the following order: -CD > -CD HO-propyl--CD> -CD. MIMS inclusion profiles of chlorobenzene and toluene showed that the presence of substituents in benzene makes the inclusion in -CD more difficult. Experiments with ferrocene--CD have also been carried out, showing that the complex rapidly dissociates in water and the resulting free -CD can complex with benzene present in the solution.     

Mass-spectrometric detection of an unstable product in silver-methanol interaction

The low pressure interaction of methanol vapors with a silver catalyst was studied by mass spectrometry. An unstable product contributing to m/e-15 was detected in this reaction. While yield of formaldehyde increased with addition of oxygen, the unstable product showed towards oxygen a reversed, decreasing trend.

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- , m/e=15. , .

     

Effect of acid-base properties of catalysts on their activity in methylmercaptane synthesis

Catalysts containing large amounts of surface acid sites are highly active, but in their presence equal yields of methylmercaptane and dimethyl sulfide are obtained. Catalysts containing predominantly strong basic sites on their surfaces are less active but more selective towards methylmercaptane formation than the former catalysts.

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, , , , . , , .

     

α,β-Butenolides

,-Dibromo--('-carbethoxyacetony)-^,-butenolide (I) reacts with amines in diethyl ether solution to give -bromo-amino--('-carbethoxyacetony)-^,-butenolides. Compounds n are converted to -bromo-amino--('-carbethoxyacetony)-^,-butenolides on reaction with amines. The corresponding arylhydrazones (VI and VII) are obtained by the reaction of I and II with p-nitro- and 2,4-dinitrophenylhydrazines. Compound I reacts with phenylhydrazine to give furopyridazine VIII.See [1] for communication IV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 867–871, July, 1972.     

A note on diffusion stabilized Pt/C oxidation catalysts: Absence of gas-liquid boundary deactivation results in relatively high efficiency (Pt/C oxidation catalysts; Part 6)

Deactivation of Pt/C aqueous phase oxidation catalysts may occur at the gas-liquid boundary. This feature explains the relatively high and stable activity of diffusion stabilized Pt/C catalysts in the oxidation of substrates with a low reactivity.

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, Pt/C : . Pt/C, , .

     

Triterpene glycosides of the holothurian Eupentacta pseudoquinquisemita

The holothurianEupentacta pseudoquinquisemita Deichmann collected in Kraternaya Bay, Ushishir Islands has yielded two triterpene pentaosides — the previously known cucumarioside C₂, and cucumarioside H, which is a new glycoside. With the aid of¹³C NMR spectroscopy and solvolytic desulfation its structure has been determined as 6-acetoxy-3-([3-O-methyl--D-xylopyranosyl-(1 3)--D-glucopyranosyl-(1 4)] [-D-xylopyranosyl-(1 4)] [-D-xylopyranosyl-(1 2)]--D-quinovopy-ranosyl-(1 2)-(4-O-sulfato--D-xylopyranosyloxy)holosta-7,22,24(trans)-triene. Cucumarioside H was also identified inEupentacta (=Cucumaria)fraudatrix from Posyet Bay, Sea of Japan.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, USSR Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 221–225, March–April, 1988.     

Review of some metallurgical problems suitable for quantitative calorimetric treatment

A review is given of various metallurgical problems treated in the author's laboratory, for which quantitative calorimetry gave very valuable information. Measurements of thermodynamic data for phase diagram calculations, vacancies in ordered alloys, annealing of steels, and the recovery and crystallization of amorphous alloys are successively examined.

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Zusammenfassung Es wird eine Übersicht über verschiedene, in unserem Laboratorium bearbeitete metallurgische Probleme gegeben, für die durch quantitative Kalorimetrie sehr genaue Informationen erhalten werden. Es wird auf Messungen thermodynamischer Daten für Phasendiagrammberechnungen, auf Fehlstellen in geordneten Legierungen, auf das Tempern von Stahl sowie auf Aufarbeitung und Kristallisation von amorphen Legierungen eingegangen.

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, . , , .

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Dedicated to Professor Dr Kurt Komarek on his 60th birthday.     

Isomerization-disproportionation of m-xylene over dealuminated mordenites

The isomerization-disproportionation of m-xylene has been investigated over a series of dealuminated mordenites characterized by Si/Al ratios varying from 5 to 15. Catalytic activity increases with the Si/Al ratio and correspondingly also the products of disproportionation. This behavior is interpreted in terms of increasing acid strength leading to a higher activity and selectivity to disproportionation through a common mechanism which involves both a parallel and a consecutive route.

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- - , Si/Al, 5 15. Si/Al, . , , , , .

     

Secondary metabolites of Astragalus danicus Retz. and A. inopinatus Boriss.

The chemical composition of the above-ground parts of Astragalus danicus and A. inopinatus collected in the Baikal region (Eastern Siberia) was studied for the first time. From A. danicus, pentacyclic triterpene saponins were isolated and identified, viz., 3-O-(-glucuronopyranosyl)-3,22,24-trihydroxyolean-12-ene, 3-O-[O-(-d-xylopyranosyl)-(12)-(-glucuronopyranosyl)]-3,22,24-trihydroxyolean-12-ene, 3-O-[O-(-d-glucopyranosyl)-(12)-(-glucuronopyranosyl)]-3,22,24-trihydroxyolean-12-ene, 3-O-[O-(-l-rhamnopyranosyl)-(12)-O-(-d-xylopyranosyl)-(12)-(-glucuronopyranosyl)]-3,22,24-trihydroxyolean-12-ene, 3-O-[O-(-l-rhamnopyranosyl)-(12)-O-(-d-glucopyranosyl)-(12)-(-glucuronopyranosyl)]-3,22,24-trihydroxyolean-12-ene, 3-O-methyl-d-chiro-inositol, and linolenic acid. In A. inopinatus, the same saponins were identified as well as tricosan-1-ol and tetracosan-1-ol, 5,7,4"-trihydroxyflavon (apigenin), and a tetracyclic triterpenoid, 20(R),24(S)-epoxycyclolanost-9(11)-ene-3,6,16,25-tetrol (cycloastragenol). All reported compounds from the both genus of Astragalus were isolated for the first time. Methanolic extracts of A. danicusand A. inopinatus exhibited low inhibitory activity with respect to the growth of HeLa cells. The chloroform fraction of A. danicus showed a strong antimicrobial activity against Staphylococcus aureus and a strong cytotoxic activity against HeLa cells.