Zum Abbau von polycyclischen aromatischen Kohlenwasserstoffen

Summary Eight further polycyclic aromatic compounds (PCA), chosen as model substances, were submitted to ozonolysis in dilute aqueous systems. The products were derivatized, separated by capillary gas-chromatography, and identified mass-spectrometrically. Aromatic carboxy acids and oxalic acid, derivatives of indane and fluorene as well as sulfones and sulfonic acids occur as reaction products. With one exception the degradation reactions of the PCA are very fast and the composition of the reaction products is largely independent of the ozonation time. The influence of ultra-sound on the reaction path has been investigated.

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Herrn Prof. Dr. W. Fresenius zum 75. Geburtstag gewidmet

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Teil II: Fresenius Z Anal Chem (1978) 293:205–207     

Struktur- und Texturprobleme bei Phosphatzementen

The setting and hardening reaction of zine phosphate cements as well as cements based on aluminum silicates and phosphoric acid, which are being used as biomedical materials, are investigated in view of microstructure of the cementing components, with emphasis upon the micro crystalline and colloidal cement phases. An attempt is being made to find a basic cementing mechanism for common reaction types of various cements.

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Mit 4 Abbildungen

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Herrn Univ.-Prof. Dr.E. Hayek zu seinem 70. Geburtstag am 9. Juli 1974 in Verehrung gewidmet.

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Struktur- und Texturprobleme bei biomedizinischen Werkstoffen, Tl. 1.     

Über die Darstellung von Trilithium-trisulfimid (Trilithium-1,3,5,2,4,6-trithiatriazin-1,1,3,3,5,5-hexaoxid) und die thermische Zersetzung einiger Salze des Trisulfimids

Trilithiumhexaoxocyclotrithiazane^* (trilithiumtrisulfimid) has been prepared for the first time by reaction of triammoniumtrisulfimid with LiOH in a solid state reaction and by using high boiling alcohols as reaction medium. The thermolysis of different salts of trisulfimid (Na-, K-, Li-, Ag-, NH₄-salt) has been studied by thermoanalytical methods in the region between 25–500 C. The course of decomposition of these compounds is discussed by IR and chromatographic measurements.

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Mit 2 Abbildungen

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Diesen Namen verwendetI. Haiduc in: The Chemistry of Inorganic Ring Systems. Wiley-Interscience. 1970.     

Staircase cyclic voltammetry of electrocatalytic reaction inhibited by the product

A model of electrocatalytic reaction influenced by the potential dependent inhibition is developed. The response of investigated mechanism is anomalous voltammogram consisting of two anodic peaks. The relationship between two peak currents and the parameters of electrode reaction was analysed theoretically.

     

Synthesen kondensierter „Hydroxy-aza- und-oxa-chinolizinone”

The synthesis of some condensed 4-hydroxy-2-pyridone derivatives by the reaction of 2,4,6-trichlorophenyl malonates (2) with azomethines incorporating the C=N bond in a ring system is reported. The reaction of 3-aryl- or 3-haloquinoxalines (1 a, b) with2 yields monopyrido-condensed quinoxalines (3 a-d), while 3-alkyl-quinoxalines (1 c, 9) react to give dipyrido-derivatives (4 and5). Dehydrogenation of5 with Pd/C is used to confirm the structure of the known product of the reaction between2 and 5,10-dihydrophenazine (8). The reaction of2 with monosubstituted quinoxalones10 a-d yields the corresponding monopyridoquinoxalones11 a-e.

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10. Mitt.:Th. Kappe, M. Hariri undF. S. G. Soliman, Arch. Pharm.309, 684 (1976).

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Aus der DissertationY. Linnau, Universität Graz, 1969.

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Aus der DissertationW. Stadlbauer, Universität Graz, 1975.     

CYCLISCHE PHOSPHONIUM- UND ARSONIUM-SALZE ALS PHASENTRANSFER-KATALYSATOREN BEI DER FINKELSTEIN- UND KOLBE-REAKTION

Abstract

Die 1,4-Heterophosphorinanium- und arsenanium-Salze 1–23 werden auf ihre Eignung als Phasentransfer-Katalysatoren bei der Finkelstein- und Kolbe-Reaktion untersucht. Es wurde gefunden:

1) Die cyclischen Phosphonium- und Arsonium-Salze sind geeignete Phasentransfer-Katalysatoren von vergleichbarer katalytischer Reaktivität.

2) Bei gegebenen Reaktionsmedien hängt die Geschwindigkeit der Umsetzungen hauptsächlich von der Art des eingesetzten Nucleophils ab.

3) Methylgruppen am Phosphor bzw. Arsen verringern die katalytische Wirkung der Oniumsalze.

The phase-transfer-catalytic behaviour of the 1,4-heterophosphorinanium and -arsenanium salts 1–23 in the Finkelstein- and Kolbe-reaction has been investigated. The results indicate that:

1) The cyclic phosphonium and arsonium salts are suitable catalysts and have similar catalytic reactivity.

2) For a given reaction medium the reaction rate depends mainly on the nature of the nucleophile used.

3) Methyl groups bonded to phosphorus or arsenic reduce markedly the catalytic reactivity of the onium salts.     

Kinetik der Umsetzung von Formaldehyd mit 2,6-Dimethyl-4-propenylphenol in alkalischem Medium

ThePrins reaction of formaldehyde is also in alkaline medium of first order for both formaldehyde and olefin, as shown by an investigation of the reaction with 2.6-dimethyl-4-propenylphenol. Mechanistic implications are discussed.

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Application of the Cleavable Isocyanide in Efficient Approach to Pyroglutamic Acid Analogues with Potential Biological Activity

Two efficient procedures have been developed for the synthesis of pyroglutamic acid analogues 28, 29, and 34. According to the first method the Ugi (4C3C) reaction is followed by a post-transformation reaction, and the second method involves the Michael addition reaction. The present methodologies demonstrate the applicability of 1-(2,2-dimethoxyethyl)-2-isocyanobenzene (15) as a cleavable isocyanide in the Ugi/ post-transformation reaction and a strong nucleophile in the Michael addition reaction. The framework of pyroglutamic acid analogues has been constructed by the selective cleavage of the C-terminal amide bond and nucleophilic addition to the activated α,β-unsaturated carbonyl group.

     

Liquid Chromatographic Determination of Excretion Patterns of Urinary Phenolic Compounds

Abstract

Excretion patterns of urinary phenolic compounds were determined by means of chromatography with Sephadex G-10, with 4-aminoantipyrine for the detection of phenolic compounds.

Derivatization for phenolic compounds is based on a coupling reaction with 4-aminoantipyrine in the presence of sodium metaperiodate. The reaction is complete within a few minutes and, thus, provides a simple detection method.

Excretion patters of samples with normal subjects and patients of catecholamine-producing tumor were determined and the results were compared.

From the data obtained, this method is shown to be useful as a screening test of some catecholamine-producing tumors.     

The Kinetics and Mechanism of the Hydrolysis of Creatinine in Urine

Abstract

Creatinine in urine concentrations are routinely measured at Aldermaston by an autoanalyser, using the Jaffe reaction, as an index of urinary excretion rates. These values are used in calculations to estimate the body content of radionuclides from their urinary excretion rates.

Unfortunately, creatinine in urine concentrations gradually decrease with sample age due to pseudo first order hydrolysis of creatinine to give creatine in the presence of ammonia. This reaction may be arrested or reversed by mineral acid.

After storage at ambient temperatures for several weeks the creatinine in urine concentration falls by around 20%, so it is good practice to analyse samples soon after provision.

The activation energy for the hydrolysis of creatinine in urine is around 60 KJ/mol over the range 20–70 °C. Hence, raising the temperature by 10 [ddot]C approximately doubles the reaction rate.     

Concise Synthesis of Photocleavable Molecular Tag for Laser Desorption Ionization Mass Spectrometry via Fries Reaction

Abstract

A new synthetic route for the photocleavable molecular tag for laser desorption ionization mass spectrometry (LDI-MS) was achieved using the Fries reaction of 2,6-dimethylphenyl ester as its key reaction. Zirconium chloride was used as uniquely efficient adjuvant to promote the reaction. The molecular tag was obtained in five steps without chromatographic purification.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Synthesis and Ldasic Properties of O,O,O-Triethyl-N-(2-Pyridyl) Imidophosphates

Abstract

The phosphorus (111) compounds are known to react readily with arylazides resulting in the formation of imi-dophosphorus compounds (Staudinger reaction)¹.

We nave obtained O,O,O-triethyl-Ii-(2-pyridyl)imido-pnosphates by the reaction of triethylphosphites with 2-pyridylazides (existing as tetrazoles) with a good yield.     

Allylic Functionalization of 2,5- and 2,4-Cyclo-Hexadiene-1,3-Dicarboxylates

A series of 2,4- and 2,5-cyclohexadiene-1,3-dicarboxylates were functionalized at the allylic position via oxidation (SeO₂, PDC/t-BuOOH) and halogenation (NBS). The regiochemical outcome for different substrates and reactions was studied and the importance of factors such as reaction mechanism, steric hindrance and reaction intermediates stability was discussed.

     

Reaction of 5-phenylpenta-2,4-dienoic acid with benzene in trifluoromethanesulfonic acid

The reaction of 5-phenylpenta-2,4-dienoic acid with benzene in CF₃SO₃H, depending on the reaction conditions, gives three products, namely, 5,5-diphenylpent-2-enoic acid and tetralone and indanone derivatives. These carbocyclic compounds are formed through the addition of two benzene molecules to the starting diene acid and subsequent intramolecular acylation.

     

One-pot synthesis of ferrocenyl-pyrimidones using a recyclable molibdosilicic H4SiMo12O40 heteropolyacid

A series of ferrocene-containing dihydropyrimidines (DHPs) were prepared by the one-pot Biginelli reaction of formylferrocene, 1,3-dicarbonyl component and urea/thiourea. The reaction was catalyzed by a commercial Keggin heteropolyacid (H₄SiMo₁₂O₄₀) as a safe, clean and recyclable catalyst. Three different synthetic protocols were examined in order to improve the yields of the reaction and to elucidate its mechanism. Intermediates of the competitive Knoevenagel reaction were also isolated. The methodology is operationally simple and provides access to highly substituted dihydropyrimidines containing ferrocene in very good yields. The catalyst can be used and recycled without appreciable loss of the catalytic activity.

     

Efficient synthesis of mono- and bis-arylated ethylenedioxy thiophene-based functional π-conjugated molecules via clay-supported palladium-catalysed direct arylation reactions

An active Pd catalyst was prepared by the modification of montmorillonite clay. The catalyst was found to be effective for the synthesis of ethylenedioxy thiophene-based π-conjugated molecules. The reaction proceeded through clay-supported Pd-catalysed direct C–H bond activation (arylation) mechanism. Preparation, characterization and application of the catalysts are reported. The products were analysed with LCMS, and comparison with reported spectral data (FT-IR, ¹H NMR). Reusability of clay-supported palladium catalyst towards direct arylation reaction was tested for three reaction cycles without a significant loss of catalytic activity.

     

HIGH TEMPERATURE REACTIONS OF HYDROGEN SULFIDE AND THIOLS WITH ORGANIC COMPOUNDS

Abstract

The high temperature reaction of hydrogen sulfide with chloro- and bromosubstituted aromatic and heteroaromatic compounds is a convenient method for synthesis of the corresponding thiols and sulfides. The reaction of hydrogen sulfide with ortho-dihalosubstituted aromatic compounds may be directed toward the formation of thianthrene or dibenzo thiophene and their derivatives. The high temperature reaction of thiophenol with chloro- and bromoderivatives of aromatic and heteroaromatic compounds affords the corresponding mixed sulfides. The reaction with ortho-substituted halogen derivatives leads to formation of the sulfur heterocycles of the thianthrene, thioxanthene and dibenzothiophenene series.

The high temperature reaction of hydrogen sulfide with vinyl chloride gives vinylthiol and thiophene. Hydrogen sulfide initiates pyrolytic transformations of thiophene, aniline and benzaldehyde into dithienyls, 5.10-dihydrophenazine and stilbene, respectively. The reaction mechanism has been discussed.     

A New Approach to P-C Bond Formation by Using Tri-Methylsilyl Phosphites

Abstract

The in situ silylation of phosphorous acid diesters to phosphorous acid triesters by hexamethyldisilazane and trimethylsilyl halides under conditions of Michaelis-Arbuzov reaction was found as an efficient and facile reaction principle for P-C bond formation.

In general the method can be applied also to Michaelis-Arbuzov reactions of phosphonous and hypophosphorous acid esters, to Tavs reaction of phosphorous and phosphonous acid esters as well as to photochemical conversions of arylhalides with trimethylsilyl phosphites. In any case described the observed yield is nearly quantitative.     

Thermokinetics on the reaction of formation of Dy[(C5H8NS2)3(C12H8N2)]

The enthalpy change of formation of the reaction of hydrous dysprosium chloride with ammonium pyrrolidinedithiocarbamate (APDC) and 1,10-phenanthroline (o-phen•H₂O) in absolute ethanol at 298.15 K has been determined as (-16.12 ± 0.05) kJ•mol^-1 by a microcalormeter. Thermodynamic parameters (the activation enthalpy, the activation entropy and the activation free energy), rate constant and kinetics parameters (the apparent activation energy, the pre-exponential constant and the reaction order) of the reaction have also been calculated. The enthalpy change of the solid-phase reaction at 298.15 K has been obtained as (53.59 ± 0.29) kJ•mol^t-1 by a thermochemistry cycle. The values of the enthalpy change of formation both in liquid-phase and solid-phase reaction indicated that the complex could only be synthesized in liquid-phase reaction.

     

Synthesis and analgesic activity of 1,3,5-trisubstituted pyrazoles containing a diterpenoid moiety

Conjugates of terpenoids with 1,3,5-trisubstituted pyrazoles were synthesized by the cross-coupling of methyl 16-(2-chloro-2-oxoacetyl)labdatrienoate with terminal arylacetylenes via the Castro—Stephens reaction and heterocyclization of arylalkyne-1,2-diones with arylhydr-azines. The structure of one reaction product was established by X-ray diffraction. The conditions for the formation of furanolabdanoid arylalkyne-1,2-diones were found. The newly synthesized pyrazoles exhibit analgesic activity in a model of chemical irritation.