Untersuchung des Zerfalls verschiedener Azoinitiatoren in Lösung

The decomposition of various symmetric and unsymmetric azo-initiators (1,1-dichloro-1,1-diphenyl-1,1-azoethane, 2,2-dichloro-2,2-azopropane, 1,1-dichloro-1,1-azocyclohexane, 2,2-diacetoxy-2,2-azopropane, 1,1-diacetoxy-1,1-diphenyl-1,1-azoethane, 1,1-diacetoxy-1,1-azocyclohexane, 2,2-dipropionoxy-2,2-azopropane, 2,2-dicapronoxy-2,2-azopropane, 4,4-dimethyl-1,4-azobutyrolactone, azoisobutyronitrile, 2-t-butylazo-2-cyanobutan, 2-t-bytylazo-1-cyanocyclohexan) in solution was studied in dependence of temperature. Volumetry and differential-scanning-calorimetry (DSC) were used to determine decomposition rates; first order kinetics was found in all cases.

     

Floroselin, a new coumarin from the roots of Seseli sessiliflorum

Conclusions A new coumarin has been isolated from the roots ofSeseli sessiliflorum for which the structure of 3-angeloyloxy-2,2-dimethyl-4-(trans-3-methylthioacryloyloxy)-3, 4-dihydropyrano-5,6:8,7-coumarin has been proposed. This is the first time that esters of 3-methylthioacrylic acid have been found in the coumarin series.All-Union Scientific-Research Institute of Medicinal Plants. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 517–521, September–October, 1970.     

2-Spiroanellated 1,3-Benzodioxoles from the Reaction of 2,3-Dihydro-1<Emphasis Type="Italic">H</Emphasis>-pyrrol-3-ones with Tetrachloro-1,2-benzoquinone

Summary. Novel spiro[1,3-benzodioxole-2,2-(2,3-dihydro-1H-pyrrol-3-ones)] were obtained from 2-aminomethylene-2,3-dihydropyrrol-3(1H)-ones and tetrachloro-1,2-benzoquinone in ethanol at room temperature. However, in addition, 3,4-dichloro-7-methoxy-5-(4-methoxyphenyl)-5,10-dihydrophenazine-1,2-dione was formed in the reaction of 1-(4-methoxyphenyl)-2-(4-methoxyphenylaminomethylene)-4,5-diphenyl-1,2-dihydropyrrol-3-one with tetrachloro-1,2-benzoquinone.     

Polarographic behavior of 2,2′-bifuryl and 2,2′-furoin

In aqueous and aqueous-ethanolic buffer solutions at pH<9, 2, 2-bifuryl and 2, 2-furoin give two-electron polarographic electroreduction waves, the half-wave potentials of which depend on the pH. The primary product of the electroreduction of 2, 2-bifuryl is trans-1,2-dihydroxy-1,2-bis(, -furyl)ethylene, which then rearranges into 2, 2-furoin. The anode-cathode wave of 2,2-bifuryl has been studied by means of a Kalousek commutator. It has been shown that the polarographic behavior of 2,2-bifuryl and 2, 2-furoin is similar to that of benzil and benzoin, but differs from the behavior of analogs of the pyridine series.     

Conversion of cyclohexene on a gold-plated palladium-nickel membrane catalyst

Under flow conditions, on the gold-covered external surface of a tube made of Pd containing 5.9% Ni cyclohexene is dehydrogenated into benzene and the hydrogen formed does not desorb but is consumed in cyclohexene hydrogenation to cyclohexane and diffuses through the membrane catalyst. In the presence of added hydrogen, cyclohexene hydrogenation takes place below 200°C. Upon the introduction of hydrogen through the membrane catalyst the hydrogenation rate strongly increases relative to the case when hydrogen is fed in mixture with cyclohexene vapors.

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- , Pd–Ni (5,9%), , . 200 °C, , .

     

Synthetic studies in the field of the curare alkaloids

By oxidation and the identification of the oxidation products, it has been shown that the -[4-(2-alkoxy-5-alkoxycarbonylmethylphenoxy)-3-methoxyphenyl] ethylamides of 4-benzyloxyphenylacetic acid obtained previously and differing in their physicochemical properties are based on the same skeleton and differ only in their spatial configuration, since on Bischler-Napieralski cyclization they give isomeric dihydroisoquinoline compounds. The structure of the latter was established by oxidation to the isomeric acids 2,2-dimethoxy-3,4,5-tricarboxy(diphenyl ether) and 2,2-dimethoxy-4,5,5-tricarboxy-(diphenyl ether); the latter is identical with the compound obtained by the degradation of the methyl ester of natural tubocurarine. 1-(4Benzyloxybenzyl)-6-methoxy-7-(2-methoxy-5-methoxycarbonyl methylphenoxy)-N-methyl-1,2,3,4-tetrahydroisoquinoline and a compound isomeric with it have also been synthesized, and the former has been shown to be identical with a substance obtained by independent synthesis from the 4-benzyl ether of N-methylcoclaurine. During the synthesis of the latter it was shown that cyclization takes place unambiguously without the formation of isomeric compounds.For part XIII, see [2].     

Bisindoles. 28. Synthesis of 7,7′-dimethyl-5,5′-bis-1H-indole

Cyclization of the 3,3-dimethyl-4,4-diphenylendihydrazone of ethyl pyruvate in polyphosphoric ester gave 7,7-dimethyl-2,2-dicarbethoxy-5,5-bis-1H-indole which was hydrolyzed and decarboxylated to give 7,7-dimethyl-5,5-bis-1H-indole.For Communication 27 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 343–345, March, 1990.     

Conversion of methanol to hydrocarbons over metal-zeolite catalysts

Ni²⁺, Cr³⁺ and Pb²⁺ exchanged CaY zeolites including mixed forms like CrNiCaY and PbNiCaY were used to study methanol conversion. The selectivity of the reaction to olefin and paraffin formation depends on the type of samples, the activation of the catalyst and the reaction conditions.

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CaY , Ni²⁺, Cr³⁺ Pb²⁺- , CrNiCaY PbNiCaY, . - , .

     

Kinetics of evolution of individual gases in the course of shale thermal decomposition

Kinetic parameters describing the evolution of C _n H _m , CH₄, CO and H₂ in the course of shale thermal decomposition were calculated by the Allakhverdov-Nirsha method allowing for sum of square difference behaviour in the kinetic parameters. The mean kinetic parameters were determined for each gas according to the parameters which were determined for the different seams of commercial deposits. The calculated results agreed well with the experiments.

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Zusammenfassung Die Ergebnisse der Berechnung kinetischer Parameter, die die Freisetzung von C _n H _m , CH₄, CO und H₂ im Verlaufe der thermischen Zersetzung von Schiefern beschreiben, werden mitgeteilt. Die Berechnungen wurden nach der Methode von Allakhverdov und Nirsha ausgeführt. Die Mittelwerte der kinetischen Parameter wurden für jedes Gas bestimmt und mit den für Material aus Flözen verschiedener industriell ausgebeuteter Lagerstätten ermittelten Parametern verglichen. Es wird gezeigt, daß die Berechnung mit den experimentellen Werten gut übereinstimmende Ergebnisse liefert.

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, C _n H _m , CH₄, CO, H₂ . - . , . , .

     

Kinetics of the thermal decomposition of alkaline earth metal hydrofluorides

The thermal stability of alkaline earth metal hydrofluorides was studied by means of a Derivatograph. The values of the activation energy, reaction order and rate constant were determined. The comparison of the kinetic parameters of the decomposition process for the complete series of hydrofluorides studied led to a certain regularity in the differences in their thermal stabilities and its correlation with the strength of the hydrogen bond in their structure.

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Zusammenfassung Die thermische Stabilität von Erdalkalihydrofluoriden wurde mit Hilfe eines Derivatographen untersucht, die Werte der Aktivierungsenergien, der Reaktionsordnung und der Geschwindigkeitskonstanten bestimmt. Der Vergleich der kinetischen Parameter des Zersetzungsvorganges wies auf eine gewisse Regelmäßigkeit in ihrer verschiedenen thermischen Stabilität, die in Zusammenhang mit der Stärke ihrer strukturalen Wasserstoffbindung steht.

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Résumé On a étudié la stabilité thermique des hydrogénofluorures des métáux alcalinoterreux et déterminé les valeurs des énergies d'activation, des ordres de réaction et des constantes de vitesse de réaction à l'aide d'un Dérivatographe. Après comparaison des paramètres cinétiques on a pu établir une certaine régularité dans le changement de la stabilité thermique en corrélation avec la force de liaison de l'hydrogène dans la structure.

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. , . .

     

On the configuration of 2,2′-bipyridyl and 5,5′-Bis-Isoxazole by means of the CNDO/2 method

The conformation of 2,2-bipyridyl and 5,5-bis-isoxazole is studied by the CNDO/2 method. Calculations suggest that the trans configuration is more stable than the cis for both systems. For 2,2-bipyridyl a minimum for a non planar form is inferred.     

Some substituted 4-aminothionaphtheno [3, 2-d] pyrimidines

Boiling 2-methyl-4-oxo-3,4-dihydrothionaphtheno[3,2-d]-pyrimidine with phosphorus oxychloride gives 2-methyl-4-chlorothionaphtheno [3,2-d]pyrimidine (II), in which the chlorine atom is mobile. Nucleophilic substitution of the mobile chlorine atom in compound II gives the 4-ethoxy,4-(N-piperidino),4-(N⁴-methyl-N-piperazino), 4-[2-(diethylamino)ethylamino],4-3-(diethylamino)-2-hydroxypropylamino]substituted derivatives.     

1,2-bis(2',6'-dimethyl-i',3'-dioxa-6'-aza-2'-silacyclooctyl-2')ethane and the corresponding ethylene and acetylene derivatives

Conclusions The reaction of 1,2-bis(methyldimethoxysilyl)ethane and the corresponding ethylene and acetylene derivatives with bis(2-hydroxyethyl)methylamine gives 1,2-bis(2,6-dimethyl-1,3-dioxa-6-aza-2-silacyclooctyl-2)ethane and the corresponding ethylene and acetylene derivatives. Analogously, 1,2-bis(vinyldimethoxysilyl)acetylene gave 1,2-bis(2-vinyl-6-methyl-1,3-dioxa-6-aza-2-silacyclooctyl-2)acetylene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1420–1421, June, 1988.     

Synthesis of 2,3,7,8-tetramethyldibenzofuran

3,4,3,4-Tetramethyldiphenyl ether readily forms 2,2-dihalo derivatives on bromination and iodination. Heating 2,2-diiodo-4,5,4,5-tetramethyldiphenyl ether with copper powder or oxidation, of 2,2-dilithio-4,5,4,5-tetramethyldiphenyl ether gives 2,3,7,8-tetramethyldibenzofuran, the structure of which was proved by alternative synthesis from 2,2-dinitroand 2,2-diamino-4,5,4,5-tetramethyldiphenyls.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1597–1599, December, 1972.     

Simple and effective method for the synthesis of 3′,5′-substituted 1-β-D-arabinofuranosyluracil

3,5-Substituted arabinofuranosyluracil is a starting compound in 2-modifications. A convenient and effective method is proposed for the synthesis of 1-(3,5-di-o-trityl--D-arabinofuranosyl)uracil by successive reactions of 2,2-cyclization of uridine, 3,5-tritylation of the 2,2-anhydrouridine, and hydrolytic cleavage of the 2,2-anhydro bond.Institute of Organic Synthesis, Riga LV-1006. Odense Universitet, Kemisk Institut, Odense, Denmark. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 975–977, July, 1996. Original article submitted April 25, 1996.     

Organodimagnesium derivatives of thiophene. 3. Synthesis of an organodimagnesium derivative of hexabromo-2,2′-dithienyl and its reaction with oxalic acid esters

It was established that the reaction of hexabromo-2,2-dithienyl with magnesium in the presence of ethyl bromide gives an organodimagnesium derivative, which reacts with oxalic acid esters to give 3,3,4,4-tetrabromo-5,5-dithienyl-diglyoxalic acid esters. Reduction of the latter with ethylmagnesium bromide leads to 3,3,4,4-tetrabromo-5,5-dithienyl-2,2-diglycolic acid esters.See [1] for Communication 2.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 468–470, April, 1981.     

Kinetics of EDTA-catalyzed oxidation of Indigo Carmine by vanadium(V)

The reaction is first order both in vanadium(V) and substrate and is markedly inhibited by H⁺ ions. Kinetic evidence for the formation of a 11 complex of vanadium(V) and EDTA is obtained. The stability constant of this complex and its thermodynamic parameters were evaluated. A suitable mechanism is proposed.

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(V), H⁺. 11 (V) . . .

     

Synthese einiger biologisch interessanter 4′-Azaflavonoide

Zusammenfassung Verschiedene, brom-, chlor-, dichlor-, brommethoxy- und phenylsubstituierte 2-Hydroxy-4-azachalkone wurden durch basenkatalysierte Kondensation geeigneter o-Hydroxy-acetophenone mit Pyridin-4-aldehyd hergestellt und in die entsprechenden 4-Azaflavone, 4-Azaflavonole und 4-Azaflavanone umgewandelt.

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Several bromo-, chloro-, dichloro-, bromomethoxy- and phenylsubstituted 2-hydroxy-4-azachalcones have been prepared by base catalyzed condensation of the appropriate o-hydroxyacetophenones with 4-pyridinealdehyde, and subsequently converted into the corresponding 4-azaflavones, 4-azaflavonols and 4-azaflavanones.

     

Discrimination between catalyst deactivation mechanisms by kinetic measurements in open systems

Two competitive mechanisms of catalyst deactivation caused by either the starting substance or the reaction product are considered. The problem of the possible discrimination between these mechanisms according to kinetic measurements in open systems can be solved by a numerical experiment on a computer.

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— , . , . .

     

Reaction of 2,2-bis(4′-hydroxy-3′-N,N-diethylaminomethylphenyl) propane with triethyl phosphite

Conclusions The reaction of 2,2-bis(4-hydroxy-3-N,N-diethylaminomethylphenyl)propane with triethyl phosphite gave 2,2-bis(4-ethoxy-3-diethylphosphonomethylphenyl)propane via the intermediate formation of a compound with a pentacovalent phosphorus atom. In the presence of acetic acid the reaction leads to 2,2-bis(4-hydroxy-3-diethylphosphonomethylphenyl)propane.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1621–1624, July, 1978.