bluuebunny/crossref_metadata_2025_split huggingface dataset:
EPR‐Untersuchungen zur Photolyse halogenierter organischer Verbindungen. I. Reine Phasen halogenierter Verbindungen (CBr4, CHBr3, CCl4, CHCl3)
Authors: Stösser R. , Pritze B. , Abraham W. , Dreher B. , Kreysig D. 
Published: December 2004

EPR‐Investigations on the Photolysis of Halogenated Organic Compounds I. Pure Halogenated Compounds (CBr4, CHBr3, CCl4 and CHCl3)EPR‐spectra of CBr4, CHBr3 and CDBr3, exposed to u.v.‐light and γ‐rays respectively, are presented. They are discussed and compared with the results of the photolysis of CH2Br2, CH3Br and CCl4, CHCl2, CH2Cl2 and CH3Cl. Under stationary conditions at 77K it was possible to identify paramagnetic species like \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CBr}_4\,^{_{\bar.}} $\end{document}, ·CBr3, ·CH3, ·C2H5, ·CCl3 and trapped electrons.
Photoinduzierte Elektronenübertragungsreaktionen zwischen aromatischen Diazoniumkationen und Anionen
Authors: Becker H. G. O. , Israel G. , Oertel Ulrike , Vetter H.‐U. 
Published: December 2004

Photoinduced Electron Transfer between Arenediazonium Cations and AnionsAnions X⊖ can act as donors in electron transfer reactions to photoexcited arenediazonium ions. The yield of the arene formed in this reaction increases with decreasing electrochemical oxidation potential E of X⊖ (X⊖ = BPh4⊖, Br⊖, HOOCCOO⊖, Cl⊖, BF4⊖). The oxidized donor X· (Cl·, ·COO⊖) and aryl radicals Ar· benig intermediates of the reductive dediazoniation of ArN2⊖ can be detected by spin trapping with nitrosodurene (ND) and phenyl‐tert‐butylnitrone (PBN). A solvent effect in the electron transfer reaction is interpreted in terms of ion pairing, where the electron transfer is favored by preorientation and a short distance between the electron donor and the acceptor previous to excitation of ArN2⊖ by light.
Substituenteneffekte in den 13C‐NMR‐Spektren von diastereomeren Chalkondihalogeniden. VI. Konfigurationsbestimmung von Chalkonrhodanhydrinen mittels lösungsmittelinduzierter Signalverschiebung in den 13C‐NMR‐Spektren
Authors: Weber Fritz Gerd , Liepert Harald , Radeglia Reiner 
Published: December 2004

Substituent Effects in 13C‐N.M.R. Spectra of Diastereomeric Chalcone Dihalogenides. VI. Assignment of Configuration on Chalcone Rhodanohydrins by Solvent Induced Shift of Signals in 13C‐N.M.R. SpectraThe erythro configuration of chalcone rhodanohydrins 1 was determined by comparison of solvent dependent shifts of C‐α and C‐β signals of 1 and both the erythro and threo isomeres of chalcone chlorohydrins 2 as standard in 13C n.m.r. spectra.
Formylation products of thioamides. XIV. Synthesis of Substituted Thiazoles and Thiophenes by the reaction of N, N′‐bis(aminomethylidene)thioureas or N‐(3‐aminothioacryloyl)‐formamidines with alkylating reagents
Authors: Knoll Alexander , Liebscher Jürgen , Radeglia Reiner 
Published: December 2004

AbstractN, N′‐Bis(aminomethylidene)thioureas 1 react with electron acceptor substituted methyl halides 2 under the formation of 2‐formamidinothiazoles 4. The reaction of N‐(3‐aminothioacryloyl)‐formamidines 5 with substituted methyl halides 2 gives either 2‐formamidinothiophenes 7 or 2‐aminovinylthiazoles 8. The 8 can be hydrolysed to corresponding 2‐hydroxyvinylthiazoles 9. 2‐Aminovinylthiazoles 11 bearing primary amino groups are obtained by transamination of the N‐(3‐aminothioacryloyl)‐formamidines 5 and subsequent reaction of the resulting 10 with substituted methyl halides 2.
Schädigung der Z‐Gruppe und Hydantoinbildung bei der Alkalischen Verseifung von Z‐Peptidestern
Authors: Schwenzer B. , Weber E. , Losse G. 
Published: December 2004

Cleavage of Z‐Group and Formation of Hydantoine during Saponification of Z‐Peptide EstersIn the course of alkaline decomposition of the tetrapeptide ester Z‐Arg(NO2)‐Gly‐Phe‐Phe‐OMe one gets a high output of a by‐product. the latter was isolated and identified by 13C‐n.m.r. spectroscopy to be the hydantoine derivative arising from a loss of Z‐group and from a cyclisation. A possibility to suppress the undesired side‐reaction by addition of benzylalcohol is proposed resulting from the discussion of a probable mechanism of reaction.
Photochemie substituierter Cycloheptatriene. XVII. 1‐Aryl‐4‐(p‐dimethylaminophenyl)‐cycloheptatriene
Authors: Abraham W. , Kupfer M. , Kreysig D. 
Published: December 2004

Photochemistry of Substituted Cycloheptatrienes. XVII. 1‐Aryl‐4‐(p‐dimethylaminophenyl)‐cycloheptatrienesThe photochemistry of the title compounds is different from that of the isomeric 1‐(p‐dimethylaminophenyl)‐4‐aryl‐cycloheptatrienes. The sigmatropic 1, 7‐hydrogen shift is dominant caused by the arylic substituent in position 1 of the seven‐membered ring. Only strong donor substituents like the p‐methoxyphenyl group in position 1 cause photovalence tautomerism.The properties of solvents influence both the quantum yields of the photoreactions and the fluorescence quantum yields. The connections between the fluorescing state and the photoreactivity are discussed. Solvent viscosity and polarity are shown to be relevant for the deactivation parameters.
Acetals and ethers. XII. Reaction Products of Prop‐2‐enal with 1,2‐ and 1,3‐Diols
Authors: Piasecki Andrzej , Burczyk Bogdan 
Published: December 2004

Abstract2‐(Hydroxyalkoxyethyl)‐substituted cyclic acetals (1; 2; 3a‐3d; 4a‐4d), derivatives of 1, 3‐dioxolane or 1, 3‐dioxane have been obtained in a p‐toluenesulphonic acid‐catalysed reaction of prop‐2‐enal with an excess of ethylene, propylene‐1, 2, trimethylene, or butylene‐1, 3 glycol. Respective 2‐vinyl‐1, 3‐dioxolanes or 2‐vinyl‐1, 3‐dioxanes were the intermediate products. The products of the reaction involving propylene‐1, 2 and butylene‐1, 3 glycols were mixtures of cis‐ and trans‐2, 4‐disubstituted‐1, 3‐dioxolanes and cis‐ and trans‐2, 4‐disubstituted‐1, 3‐dioxanes. The structure of HOROCH2CH2‐ substituents at C‐2 atom of 1, 3‐dioxacyclane ring has been proved through 2, 4‐dinitrophenylhydrazone derivatives of the corresponding aldehydes HOROCH2CH2CHO that, however, could not be isolated as individual compounds.
1H‐NMR‐spektroskopische Untersuchungen zur Azo‐Hydrazon‐Tautomerie in substituierten 1‐Phenylazo‐2‐naphtholen
Authors: Haessner R. , Mustroph H. , Borsdorf R. 
Published: December 2004

1H‐N.M.R. Spectroscopic Investigations of the Azo‐Hydrazon‐Equilibrium in Substituted 1‐Phenylazo‐2‐naphtholsIn substituted 1‐phenylazo‐2‐naphthols an equilibrium between the azoic and the quinoid hydrazone form is observed. It is possible to obtain the equilibrium constants by means of 1H‐n.m.r.‐spectroscopy in CDCl3. Both chemical shifts δH−3 and δH−8 in the naphthalene ring system can be used to determine independently the equilibrium constants. 1‐Phenylazo‐2‐naphthylamine and 1‐(pyrid‐2‐ylazo)‐2‐naphthole were used as reference substances for the pure azoic and hydrazone form, respectively. An appropriate correction is introduced to compare the different influence of OH‐ und NH2‐groups, respectively, on the protons H‐3 and H‐8.All equilibrium constants measured show a linear correlationship with respect to Hammett‐σ‐constants of the substituents attached to the phenyl ring. The standard reaction entropy for the conversion of the azoic form into the hydrazone form is always negative and of nearly identical magnitude. Obviously, no substituent effect to this value exists. One possibility to interprete these results is to assume that the quinoid hydrazone form shows a higher tendency to aggregation.
Iminoformylierung substituierter Crotonnitrile. I. Synthese neuer N, N‐disubstituierter 4‐Amino‐1,1‐dicyanbuta‐1,3‐diene
Authors: Köckritz P. , Sattler R. , Liebscher J. 
Published: December 2004

Iminoformylation Reaction of Substituted Crotonnitriles. I. Synthesis of New N, N‐Disubstituted 4‐Amino‐1, 1‐dicyanobuta‐1, 3‐dienesA useful and efficient method for the synthesis of 4‐amino‐1, 1‐dicyanobuta‐1, 3‐dienes 10‐20 based on the iminoformylation reaction of crotonnitriles 7‐9 with the system triethyl orthoformate/secondary amine in the presence of an acidic catalyst is described. This novel route to the title compounds yields products which are easy to isolate and to purify and also allows to prepare the hitherto unknown N‐aryl substituted 4‐amino‐1, 1‐dicyanobuta‐1, 3‐dienes. Hence it is advantageous as compared to existing iminoformylation reactions of crotonnitriles using formamide acetals.
Photooxidation von Leukofarbstoffen. X. Untersuchungen zur Photooxidation von Di‐kalium‐anthracen‐9,10‐ylen‐bis‐sulfat
Authors: Langbein H. , Hinzmann G. , Grummt U.‐W. , Koch R. , Fassler D. 
Published: December 2004

Photooxidation of Leuco Dyes. X. Investigation of the Photooxidation of Di‐potassiumanthracene 9,10‐ylene‐di‐sulfatePhotolysis of the title compound (DHAE) in water or ethanol produces anthraquinone and anthrone. In deoxygenated solutions 9,10‐dihydroxyanthracene is detected as a long lived intermediate. Laser and conventional flash photolysis reveals three short‐lived transients with lifetimes of 200 ns, 2 and 410 ms. Different temperature dependencies are observed for the fluorescence and the photolysis quantum yields. This is interpreted by two successive thermally activated processes: photohomolysis of OS bond and escape of the radical pair from the solvent cage. The results are discussed with the help of a reaction scheme proposed for the photolysis of DHAE.
Über die Reaktion von Chloranil mit Cyanidionen – eine ESR‐Studie
Authors: Rehorek Detlef , Janzen Edward G. 
Published: December 2004

On the Reaction of Chloranil with Cyanide Ions – an ESR StudyThe reaction of chloranil 1 with cyanide ions in acetonitrile and methanol solutions has been studied. The ESR Spectra revealed the formation of semiquinone anion radicals 7,8, and 9. The latter has been found as its protonated form in methanol only. In addition, both 1 and 2,3‐dicyano‐5,6‐dichloro‐1,4‐benzoquinone 4 gave tetracyanoethylene anion radicals 6 upon reaction with cyanide ions in acetonitrile. Using 13C‐labelled cyanide 6 was shown to originate from the fragmentation of the cyanide addition product to 4. Using the spin trapping technique it was found that no cyanyl free radicals are formed during the thermal reaction of either 1 or 4 with cyanide ions.
Reactions of 4‐Chloromethyl‐1,3‐dioxolan‐2‐one with Phenols as A New Route to Polyols and Cyclic Carbonates
Authors: Rokicki G. , Pawlicki J. , Kuran W. 
Published: December 2004

AbstractReaction of 4‐chloromethyl‐1,3‐dioxolan‐2one (1) with phenol in the presence of potassium carbonate was studied and found to yield 4‐phenoxymethyl‐1,3‐dioxolan‐2one (2) and 3‐phenoxypropan‐1,2‐diol (3). The latter compound 3 was also found to be formed as the main product in the reaction of 1, phenol and sodium hydroxide at a temperature higher than 90°C.The effect of various factors on the reaction course and the yield of 2 and 3 was examined.It was found that the reaction studied can be extended to those of difunctional phenols such as 2,2‐di(4‐hydroxyphenyl)‐propane producing the corresponding tetrahydroxyderivative – 2,2‐bis‐[4‐(2,3‐dihydroxypropoxy)phenyl]propane.
Revisitation of Formaldehyde Aniline Condensation. I High Yield Synthesis of 1,3,5‐Triphenylhexahydro‐symtriazine and its X‐Ray Crystal Structure Determination
Authors: Giumanini Angelo G. , Verardo Giancarlo , Randaccio Lucio , Bresciani‐Pahor Nevenka , Traldi Pietro 
Published: December 2004

AbstractA rapid and efficient preparation of 1,3,5‐triphenylhexahydro‐sym‐triazine (10) using paraformaldehyde is reported. The trimeric nature of the compound and its structure in solid state, where a biaxial chair conformation is favoured, are conclusively shown by X‐ray diffraction analysis. A recent report on a preparation of 1,3‐diphenyl‐1,3‐diazetidine is invalidated.
Sensibilisierte Photooxidation und 13C‐NMR‐spektroskopische Untersuchung von 5,6‐Dihydrodicyclopentadien‐Derivaten
Authors: Fanghänel E. , Keita Y. , Radeglia R. , Schmidt W. 
Published: December 2004

Photooxidation and 13C N.M.R. Spectroscopic Investigation of 5,6‐Dihydrodieyelo‐pentadiene DerivativesThe sensitized photooxidation of endo‐5,6‐dihydrodicyclopentadiene (2) by singulet oxygen gives via the corresponding hydroperoxide (10) exo‐1‐hydroxy‐5,6‐dihydrodieyelopentadiene (7a). Starting from exo‐5,6‐dihydrodicyclopentadiene (6) exo‐5,6‐dihydrodicyelopentadien‐1‐one (12) is formed. The 13C n.m.r.spectroscopical data of these compounds and of other hydroxy, alkoxy and acyloxy dihydrodieyclopentadiene derivatives are discussed in relation on their structure.
Elektrochemische Adamant‐1‐ylierungen und Tetrahydro‐exo‐dicyclopentadien‐9‐ylierungen von Azomethinen
Authors: Hess U. , Lieberenz C. , Feuerherd B. 
Published: December 2004

Electrochemical Reductive Alkylation of Azomethines with 1‐Bromadamantane and 9‐Bromo‐tetrahydro‐exo‐dicyclopentadieneElectrochemically generated radical anions of Schiffbases 1a—11 react in DMF and in the presence of bridgeheadhalogenides as 1‐bromoadamantane and 9‐bromo‐tetrahydro‐exo‐dicyclopentadiene to 1‐[α‐(aryl‐ or alkylamino)‐α‐arylmethyl]‐adamantanes and the correspondent 9‐tetrahydro‐exo‐dicyclopentadienes. In the course of SET‐mechanism originating bridgehead radicals couple with the azomethine‐radicalanions at the position of the highest unpaired electron density, which is predominantly the carbon of the C,N‐double bond. Only in cases when this density at the N‐atom is relatively high, or steric hindrance impedes C‐alkylation, N‐hydroalkylated products as N,N‐disubstituted 1‐aminoadamantanes and 9‐amino‐tetrahydro‐exo‐dicyclopentadienes are formed. Product distribution, cyclic‐voltammetric results and quantumchemical data are discussed in terms of mechanism.
Stereochemie der 2‐Aryl‐cyclohexanone. I. Konfigurations‐ und Konformationsanalyse der cis‐trans‐isomeren 2,6‐Dimethyl‐2‐aryl‐cyclohexan‐1‐one über ihre Oxime
Authors: Palitzsch P. , Huneck S. , Fischer F. 
Published: December 2004

Stereochemistry of the 2‐Aryl‐cyclohexanones. I. Analysis of the Configuration and Conformation of the cis‐trans‐Isomeric 2,6‐Dimethyl‐2‐aryl‐cyclohexan‐1‐ones by the Aid of their OximesDesulfurization of the n‐butylthiomethylene ketone 6 with Raney nickel yields a mixture of trans‐ and cis‐stereoisomers 7 and 8, the conformations of which are 7A and 8B, respectively. While the ketone 7 gives rapidly and quantitatively the oxime 9, the isomer 8 reacts much more slowly to a mixture of 9 and 10. A detailed analysis of the configuration and conformation of the ketones 7 and 8 as well as the oximes 9 and 10 is given.
Zuordnung von Schwingungsspektren organischer Moleküle durch MNDO‐Berechnungen
Authors: Dathe K. , Bögel H. 
Published: December 2004

Assignment of the Vibrational Spectra of Organic Molecules by MNDO CalculationsWavenumbers and intensities of the molecular vibrations can be calculated by the semi‐empirical SCF‐MO method, MNDO. The calculated normal coordinates show the displacements of the atoms in the course of the vibration and provide the assignment of mode and symmetry of the vibrations. This will be shown for the following examples: acetylene, ethylene, substituted and deuterated ethylenes, acetonitrile as well as for EDA complexes. We found a good qualitative agreement between calculated and experimentally observed IR‐data.
Zur Anwendung von Lanthanoid‐Verschiebungsreagenzien bei der NMR‐spektroskopischen Untersuchung von Gemischen monofunktioneller Kohlenwasserstoffe
Authors: Zopf U. , Brunn J. , Radeglia R. 
Published: December 2004

Application of Lanthanide Shift Reagents in 1H‐N.M.R.‐Spectroscopic Investigations of Mixtures of Monofunctional HydrocarbonsThe influence of n.m.r. shift reagents on the 1H‐n.m.r.‐spectra of mixtures has been investigated. Hydrocarbons of the type CH3(CH2)nX (X = OH, CHO, COR, COOCH3, COOH, OR with R = Methyl‐, Ethyl‐, n‐Propyl‐, n‐Butyl‐ and n = 1,2) served as model substances. The components of the mixtures compete with the shift reagent. Relative equilibrium constants have been calculated to describe this behavior in mixtures. Several equations have been deduced and tested to describe the induced shifts of the protons in mixtures. These equations are applicable to qualitative and quantitative analysis of unknown mixtures.
Untersuchungen zum UV/VIS‐Spektralverhalten von Azofarbstoffen. XV. Eine Analyse der Absorptionsspektren von 4,4′‐Diaminoazobenzenen
Authors: Haessner C. , Mustroph H. 
Published: December 2004

Studies on UV/VIS Absorption Spectra of Azo Dyes. XV. An Analysis of the Absorption Spectra of 4,4′‐DiaminoazobenzenesIn the visible absorption spectrum 4,4′‐bis‐diethylaminoazobenzene shows two absorption maxima (λmax = 426 nm and λmax = 477 nm) with high intensity. Quantum chemical calculations and examination by peak separation of six 4‐substituted azobenzenes and six 4′‐substituted 4‐diethylaminoazobenzenes (1a–k) indicate that the longest wavelength band is due to a n‐π* transition and the other band is due to a π‐π*‐transition.This is verified using an increment system for n‐π* absorption maxima. A linear relation is found between intensity ratios of the two bands and the HAMMETT‐σ‐constants of the substituents. With increasing electron releasing tendency of the substituents the absorption intensity of the n‐π*‐band increases.
Oxidative Kupplung von 5‐Amino‐pyrazolen mit p‐Phenylendiaminen
Authors: Hennig L. , Hofmann J. , Wilde H. , Mann G. 
Published: December 2004

Oxidative Coupling of 5‐Aminopyrazoles with p‐PhenylenediaminesBy oxidative coupling of 5‐amino‐3‐methyl‐1‐phenyl‐pyrazole 4 with N,N‐diethyl‐p‐phenylenediamine the 4‐(4‐N,N‐diethylamino‐phenylimino)‐3‐methyl‐1‐phenyl‐2‐pyrazolin‐5‐imin 5 is formed. 5 is oxidized very easily to the 1H‐pyrazolo[3,4‐b]quinoxaline 6a. The Z/E‐isomerism of the azomethine dye is investigated by dynamic n.m.r.‐spectroscopy. 1H‐Pyrazolo[3,4‐b]quinoxalines (6a–d) are also formed by reaction of 1,3‐disubstituted 5‐aminopyrazoles with p‐nitroso‐dialkylanilines.
Zur Reaktion von 5,6‐Dihydro‐1,4‐oxathiin‐4,4‐dioxiden mit Nucleophilen
Authors: Göhmann P. , Schröder L. , Zschunke A. 
Published: December 2004

About the Reaction of 5,6‐Dihydro‐1,4‐oxathiin‐4,4‐dioxides with Nucleophilic CompoundsBy reactions of 5,6‐dihydro‐1,4‐oxathiin‐4,4‐dioxides (1, 5, 8) with thioles, amines and CH‐acid compounds 2‐substituted ethansulfonylcarbonyl compounds are formed. The structures of the reaction products are determined by elemental analysis, i.r. and 1H‐n.m.r.‐spectroscopy.5,6‐Dihydro‐1,4‐oxathiin‐4,4‐dioxide sind gut zugänglich durch die Oxidation von 5,6‐Dihydro‐1,4‐oxathiinen mit Wasserstoffperoxid. Besonders zur Darstellung der 5,6‐Dihydro‐2‐methyl‐3‐carboxamido‐1,4‐oxathiin‐4,4‐dioxide, von denen einige im Pflanzenschutz wegen ihrer systemischen fungiziden Wirkung Bedeutung erlangten, wurden verschiedene Methoden beschrieben [1, 2]. In ähnlicher Weise lassen sich auch die entsprechenden Ester und Säuren synthetisieren.
CW CO2‐Laser SF6‐Photosensitized Pyrolysis of Tetralin
Authors: Pola J. , Trka A. , Zimmermann G. 
Published: December 2004

AbstractCW CO2 laser photosensitized (SF6) pyrolysis of tetralin proceeds mainly via dehydrogenation channel affording 1,2‐dihydronaphthalene and naphthalene. Less important ring cleavage products are indene, styrene, ethylbenzene, toluene, and benzene, together with ethylene and methane. No occurrence of polyaromatics and high yields of ethylene compared to methane are the features differing this process from high temperature conventional pyrolysis.
Synthesis of a Versatile Prostaglandin Intermediate by Ozonization of endo‐cis‐Bicyclo[3.3.0]oct‐6‐en‐2‐ol
Authors: Theil F. , Mahrwald R. , Schick H. , Mel'nikova V. I. , Vasil'eva L. L. , Pivnitsky K. K. 
Published: December 2004

AbstractThe ozonization of endo‐cis‐bicyclo[3.3.0]oct‐6‐en‐2‐ol (1) in methanol followed by reduction with dimethyl sulfide in the presence of traces of an acid yields in a one‐pot procedure an anomeric mixture of 3‐exo‐methoxy‐ and 3‐endo‐methoxy‐2‐oxabicyclo[3.3.0]octane‐6‐endo‐carbaldehyde (3a and 3b) in a ratio of 9:1. This mixture is converted by base catalyzed epimerization in an overall yield of about 65% into a mixture of the anomeric 6‐exo‐aldehydes 5a and 5b, a versatile starting material for the synthesis of prostaglandins of the PG2‐type.
Determination of the main products and intermediates of the Oxidation of Medium Normal Paraffins in dependence on the conversion indirect evidence for the importance of bifunctional intermediates
Authors: Engelmann Eleonore , Just Gerhard , Pritzkow Wilhelm , Rudolf Matthias , Spindler Gerald , Tien Tieu Dung , Voerckel Volkmar , Wittekind Volker 
Published: December 2004

AbstractThe mole numbers of the starting paraffins, of the intermediate alcohols and ketones with the same chain lengths, of the lower alkan‐2‐ones, of the carboxylic acids, and of the esters were determined at different reaction times for the oxidations of n‐tridecane, n‐tetradecane, and n‐pentadecane with molecular oxygen at 140°C in the presence of 0.1% Mn‐stearate. In the stationary region of the oxidation about 1.2 moles of acids and 0.7 moles of esters are formed from 1 mole of paraffin consumed. The relative oxidation rates of alcohols and of ketones with reference to the starting paraffins were estimated from the mole numbers of the starting paraffins, the alcohols and the ketones at the maxima of the alcohols and the ketones. These values are higher than those determined by competitive oxidations, and this discrepancy is an indirect evidence of the formation of bifunctional intermediates from the starting paraffins. The relative rates of the formation of alcohols, ketones, and bifunctional products from normal paraffins were estimated.
Strukturuntersuchungen an einem Produkt der intramolekularen Diels‐Alder‐Reaktion Konfigurations‐ und Konformationsanalyse von 5‐Methyl‐2‐phenyl‐1H‐2,3,3a,4,5,7a‐hexahydroisoindol‐1‐on
Authors: Hauser Andre , Gründemann Egon , Preuschhof Helmut , Schmitz Ernst , Kuban Ralf‐Jürgen 
Published: December 2004

Structure Elucidation of a Product of Intramolecular Diels‐Alder‐Reaction: Configurational and Conformational Analysis of 5‐Methyl‐2‐phenyl‐1H,2,3,3a,4,5,7a‐hexahydroisoindol‐1‐oneN‐Allyl‐N‐phenylsorbamide 1 cyclizes at 160°C to give 5‐methyl‐2‐phenyl‐1H,2,3,3a,4,5,7a‐hexahydroisoindol‐1‐one 2. As a result of this intramolecular [4 + 2] cycloaddition four stereoisomeres 2a–2d can exist. The 1H and 13C n.m.r. data are given. The 1H n.m.r. studies demonstrate that the product of Diels‐Alder cyclisation is the result of cis‐fusion of the two rings. The nuclear Overhauser effect data provide further evidence for 2a in which the carbonyl group and methyl one are trans‐arranged. The n.m.r. results are confirmed by X‐ray studies.
Elektrochemische Carboxylierung substituierter Vinylketone
Authors: Rüttinger H.‐H. , Matschiner H. , Gollnow W. D. 
Published: December 2004

Electrochemical Carboxylation of Substituted Vinyl Ketonesα‐Chlor‐β‐acyl‐vinylsulphides (1a–f) and keten‐S, N‐acetales (3a,b) are reduced in the presence of CO2 at the cathode to yield the corresponding acids (4a–f resp. 5). Whereas the carboxylation of 1 proceeds via elimination‐addition mechanism, the reduction of 3 is similar to the keten‐S, S‐acetales described earlier an EC (addition) EC (elimination) sequence.
The Structure of 9,9′‐Diethyl‐3,3′‐azocarbazole as elucidated by dipole moment measurements
Authors: Wacławek W. , Kyzioł J. , Frey H. , Fanghänel E. 
Published: December 2004

Abstract9,9′‐Diethyl‐3,3′‐azocarbazole (2) obtained through the reduction of the nitro derivative with lithium aluminium hydride is the E‐isomer according to dipole moment measurements. The rotational state of 2 is also discussed.