bluuebunny/crossref_metadata_2025_split huggingface dataset:
Steroide. 66.1H‐NMR‐Untersuchungen. Konfigurationszuordnung 15, 16, 17‐trisubstituierter Steroide
Authors: Schönecker B. , Tresselt D. , Schubert G. , Ponsold K. 
Published: December 2004

Steroids. 66.1H‐N.M.R.‐Investigations. Configurational Assignment of 15, 16, 17‐Trisubstituted SteroidsThe1H‐n.m.r.‐spectra of 15, 16, 17‐trisubstituted estra‐1,3,5(10)‐trienes are discussed in view of the configurational assignment of the substituents. A reliable elucidation of their stereo‐chemistry is possible on the basis of the coupling constants J16H,17H, J15H,16Hand J14αH,15H. Additional parameters are the chemical shifts of the 15‐, 16‐, 17‐ and 18‐protons (13β‐methyl group) and the downfield shift of carbinol proton signals, caused by the reaction of hydroxyl groups with trichloroacetyl isocyanate. The chemical shifts of the 13β‐methyl group can be calculated for compounds with trans configuration from substituent increments and for the other compounds by comparison with the chemical shifts of 16, 17‐disubstituted compounds. The influence of different 16α‐substituents on the chemical shifts of 15α‐ and 17α‐protons is investigated. The downfield shifts of 15‐ and 17‐proton signals due to the addition of trichloroacetyl isocyanate to 15, 17‐diols depend on the configuration of the 16‐substituents.
Konstitution und Redoxstabilität von Kupfer(II)‐Komplexen mit substituierten Hydrazinen
Authors: Kempe G. , Bögel M. , Roewer G. 
Published: December 2004

Constitution and Redox Stability of Copper(II)‐Complexes with Substituted HydrazinesCuCl2 reacts with substituted hydrazines forming chelates of the CuIIL2Cl2 type (L = RCONHNH2, RCONHN(C6H5)2, RCONHNHCOR, H2NNHCO(CH2)nCONHNH2) which are characterized by quantitative analysis, i.r. and e.p.r. spectra. The complex polyhedron exhibits the geometry of a tetragonally distorted octahedron of C2v symmetry. The complexes undergo intramolecular redox decomposition in acetonitril forming Cu(I) species.The rate constants increase with decreasing half wave oxydation potential and decreasing Homo energy of the hydrazine ligands, respectively.
Über die Photochromie der Fulgide. IX Untersuchungen zur Photochemie des α‐3,5‐Dimethyoxyphenyl‐δ‐δ‐dimethylfulgids
Authors: Ilge H.‐D. , Langbein H. , Reichenbächer M. , Paetzold R. 
Published: December 2004

The Photochromism of Fulgides. IX. Investigations of the Photochemistry of α‐3,5‐Dimethoxyphenyl‐δ,δ‐dimethylfulgideThe mechanism of photoisomerization of α‐3,5‐dimethoxyphenyl‐δ, δ‐dimethylfulgide was investigated by means of u.v./vis‐ and fluorescence spectroscopy. The quantum yields of E‐Z isomerization and cyclisation were determined in various solvents and at different temperatures. Triplet sensitization of E‐Z isomerization by several sensitizers has been found. The thermal dark reactions of the deep coloured species were reinvestigated.
Über einige Zusammenhänge zwischen massenspektrometrischen Ionenhäufigkeiten und Moleküleigenschaften an element‐organischen Verbindungen der Gruppe IVb. Massenspektren der Trialkylhydride des Si, Ge und Sn
Authors: Hottmann K. 
Published: December 2004

About Some Correlations between Mass‐spectral Abundances of Ions and Properties of Molecules on Element‐organic Compounds of IVb‐ElementsMass Spectra of Symmetrical Trialkylhydrids of Si, Ge and SnThe monoisotopic mass spectra of (C2H5)3ZH, (n‐C3H7)3ZH and (n‐C4H9)3ZH (Z = Si, Ge, Sn), (CH3)3SiH and (C2H5)3SiD at 70 eV are reported. The main reactions and changes in the competition behaviour with variation of central atom Z and length of alkyl‐chain are discussed in terms of physical‐organic theory of mass spectra (POT) and of QET. There are some serious discrepancies with respect to the POT. The fragmentation behaviour is in good agreement with consequences of the QET. The analogic carboniumcompounds are included in the discussion.
Aktivierungsentropien radikalischer Additionsreaktionen mittels MINDO/3‐UHF‐Rechnungen
Authors: Köhler H.‐J. , Knoll H. 
Published: December 2004

Activation Entropies of Free Radical Addition Reactions via MINDO/3‐UHF‐CalculationsA MINDO/3‐UHF study on the additions of methyl radicals to acetone, formaldehyde, ethylene, and isobutene indicates that the transition state occurs later with non‐terminal C‐addition as compared to terminal C‐addition. Distinctly lower activation entropies are obtained for non‐terminal addition.
Push‐pull‐Butadiene. II [1]. Reaktionen von 2‐Aryl‐4,4‐bis(methylthio)buta‐1,3‐dien‐1,1‐dicarbonitrilen mit Malononitril und Cyanessigsäure‐ethylester
Authors: Peseke K. 
Published: December 2004

Push‐pull‐Butadienes. II. Reactions of 2‐Aryl‐4,4‐bis(methylthio)‐1,3‐butadiene‐1,1‐dicarbonitriles with Malononitrile and Ethyl Cyanoacetate2‐Aryl‐4,4‐bis(methylthio)‐1,3‐butadiene‐1,1‐dicarbonitriles 1 react with sodium salts of malononitrile or ethyl cyanoacetate 3 to give 4‐aryl‐2‐methylthio‐1,4‐pentadiene‐1,1,5,5‐tetracarbonitriles and ethyl‐4‐aryl‐1,5,5‐tricyano‐2‐methylthio‐1,4‐pentadienecarboxylates 4, respectively. Also, arylethylidenemalononitriles 5 and bis(methylthio)methylenemalononitrile or ethyl bis(methylthio)methylenecyanoacetate 6 afford 4. Substituted dihydropyridines 8 are prepared by treating 4 with aromatic amines. Compounds 4 d, e can be converted to 2‐amino‐6‐aryl‐4‐methylthio‐benzene‐1,3‐dicarbonitriles 11 a, b.
Synthese von N‐sulfinylgeschützten Aminobenzylhalogeniden und Umsetzung mit Nucleophilen
Authors: Beckert R. , Mayer R. 
Published: December 2004

Synthesis of N‐Sulfinylprotected Aminobenzylhalides and Reactions with NucleophilesN‐Sulfinylaminotoluenes 3 react with sulfuryl chloride or N‐bromosuccinimide to give N‐sulfinylaminobenzylchlorides 4 and N‐sulfinylaminobenzylbromides 5, respectively.o‐N‐Sulfinylaminobenzylchloride 4 a can also be synthesized by the reaction of o‐aminobenzylalcohol 6 with thionyl chloride.Nucleophiles react with benzylhalides 4 and 5 to form aminobenzyl ethers, thioethers, and amines 7–9.Tetrahydrochinazolinethione 11 can be formed by the reaction of 4 a or 5 a with thiocyanate ions followed by the hydrolysis of intermediate 10.
Untersuchung zur Ringöffnungspolymerisation von 2‐Phenoxymethyl‐1,4,6‐trioxa‐spiro‐[4,4]‐nonan
Authors: Klemm E. , Haase L. 
Published: December 2004

Investigation of Ring‐Opening Polymerization of 2‐Phenoxymethyl‐1,4,6‐trioxa‐spiro[4,4]‐nonanUnder the conditions of a radical induced cationic ringopening‐polymerization the spiro ortho ester 1b can be polymerized with diphenyliodoniumtetrafluorborat/benzpinacol (1:1). The optimal initiator concentration is 2–2.5 mol‐% Ph2I+BF4−. The average molecular weight is 6000, Tg = −4°C. Polymerization of 1b in presence of BF3 · Et2O produced identical results. The structure of polymer 2b was indicated by its analysis as well as its infrared spectra.
Untersuchungen zur Sulfochlorierung von Paraffinen. X. Über die Anwendbarkeit additiver Inkremente bei der Auswertung der 13C‐NMR‐Spektren von Alkanmono‐ und ‐disulfochloriden und von Chloralkansulfochloriden
Authors: Radeglia R. , Schmidt‐Renner W. 
Published: December 2004

Studies on Sulphochlorination of Paraffins. X. The Application of Additive Increments for the Interpretation of 13C‐N.M.R. Spectra of Alkane Mono‐ and Disulphochlorides and of Chloroalkane SulphochloridesIncrements which consider the influence of chlorine and sulphonylchloride substituents on the 13C‐n.m.r. shifts of alkanes were calculated and discussed. The application of additive increments for the calculation of 13C‐n.m.r. chemical shifts of alkane‐1,2‐disulphonylchlorides, branched alkane monosulphonylchlorides, sulphochlorinated 1‐alkylchlorides and chlorinated 1‐alkane sulphonylchlorides is demonstrated. The limitations of the method are discussed.
Synthese und dielektrische Eigenschaften kristallin‐flüssiger alkyliminomethyl‐substituierter Benzoesäurephenylester
Authors: Weissflog W. , Möckel P. , Tschimeg Sh. , Kresse H. , Demus D. 
Published: December 2004

Synthesis and Dielectric Properties of Liquid Crystalline Alkyliminomethyl‐Substituted PhenylbenzoatesThe synthesis of 4‐n‐alkyliminomethyl‐phenyl‐4′‐n‐alkoxybenzoates and their mesomorphic properties are described. We have investigated the dielectric constants and the relaxation frequencies (MHz‐region) of the nematic and smectic A phases.
Zur Pyrolyse von Cycloalkenoaromaten
Authors: Günschel H. , Zimmermann G. , Lorenz R. , Ondruschka B. , Nowak S. 
Published: December 2004

On the Pyrolysis of CycloalkenoaromaticsThe products of pyrolysis of tetraline (1), indane (2), 2‐methylindane (3), and tetrahydroacenaphthene (4) in mixtures of n‐paraffins were analyzed by gas chromatography. Results show that by temperatures between 700° and 800°C and residence times of about 0.2 s more than 80% of the reaction products are aromatics. The main pathway of the decomposition of 1, 2, and 4 is the dehydrogenation in direction to the corresponding complete aromatic systems or indene respectively. In the case of 3 we found less than 10% of 2‐methylindene but more than 40% of skeleton isomeres. The formation of skeleton isomeres can be explained by the concept of radical rearrangements.
Synthese von Pyrrolo[1,2‐a]chinazolinonen, Indolo[1,2‐a]chinazolinonen, Pyrrolo[1,2‐a]thieno[3,2‐e]pyrimidinonen, Benzothieno[3,2‐e]‐pyrrolo[1,2‐a]pyrimidinonen und 6H‐Cyclohepta[4,5]thieno‐[3,2‐e]pyrrolo[1,2‐a]pyrimidinonen
Authors: Süsse M. , Johne S. 
Published: December 2004

A Synthesis of Pyrrolo[1,2‐a]quinazolinones, Indolo[1,2‐a]‐quinazolinones, Pyrrolo[1,2‐a]thieno[3,2‐e]pyrimidinones, Benzothieno[3,2‐e]pyrrolo[1,2‐a]pyrimidinones and 6H‐Cyclohepta[4,5]‐thieno[3,2‐e]pyrrolo[1,2‐a]pyrimidinonesα‐Cyano‐γ‐halo‐crotonnitriles (1) synthesized (e.g. via Knoevenagel reaction and by subsequent halogenation) react with primary arylamines (2) to substituted 1‐aryl‐2‐amino‐3‐cyano‐pyrroles (3). We found that the reaction yields pyrrolo[1,2‐a]quinazolin‐5‐ones (6) in a one‐pot procedure if anthranilic esters (4) and compounds of the general formula5are used. The analogous treatment with 2‐amino‐3‐ethoxy‐carbonyl‐thiophene derivatives (8) leads to pyrrolo[1,2‐a]thieno‐[3,2‐e]pyrimidin‐5‐ones, benzothieno[3,2‐e]pyrrolo[1,2‐a]pyrimidinones and 6H‐Cyclohepta[4,5]‐thieno[3,2‐e]pyrrolo[1,2‐a]pyrimidinones as thiadiazastereoid analogs9.This reaction is suitable for the synthesis of various heterocyclic ring systems.
Mikrobielle Reduktion 2,2‐disubstituierter Cyclopentan‐1,3‐dione. Darstellung chiraler Cyclopentanderivate für die Synthese von 8‐Methyl‐prostaglandinen
Authors: Schwarz S. , Truckenbrodt G. , Meyer M. , Zepter R. , Weber Gisela , Carl Constanze , Wentzke M. , Schick H. , Welzel H.‐P. 
Published: December 2004

Microbial Reduction of 2,2‐Disubstituted Cyclopentan‐1,3‐diones. Synthesis of Chiral Cyclopentane Derivatives Useful as Intermediates for 8‐Methyl ProstaglandinsThe microbial reduction of the 2,2‐disubstituted cyclopentan‐1,3‐diones 3ac giving rise to the chiral compounds 2, 4b and 4c is described.The incubation products can be used as intermediates for 8‐methyl prostaglandins.The structures of the fermentatively formed compounds, including their chirality and optical purity have been established by comparison with authentic specimen (cp. 2) or by chemical and spectroscopic methods (cp. 4b, 4c) respectively.
1H‐ und 13C‐NMR‐chemische Verschiebungen von 5‐Ring‐Schwefel‐ und Selenheterocyclen Ein Beitrag zum Zusammenhang zwischen Elektronenstruktur und 13C‐chemischer Verschiebung von CO‐, CS‐ und CSe‐Gruppierungen
Authors: Poleschner H. , Radeglia R. , Fanghänel E. 
Published: December 2004

1H‐ and 13C‐N.M.R. Chemical Shifts of 5‐Membered Sulfur and Selenium Heterocycles A Contribution about the Relation between Electronic Structure and 13C Chemical Shifts of CO, CS, and CSe GroupsThe 1H‐ and 13C‐N.M.R. chemical shifts of 1,3‐dithiole‐ 1–3, 1,3‐thiaselenole‐4–6 and 1,3‐diselenole‐2‐ones, ‐thiones and ‐selones 7–9 and the 13C‐N.M.R. chemical shifts of the corresponding saturated compounds 1,3‐dithiolane‐2‐one 10, ‐thione 11 and ‐selone 12 as well as 1,3‐diselenolane‐2‐thione 13 and ‐selone 14 are submitted. The 13C chemical shifts of the ring‐carbon atoms C‐4, C‐5 and C‐2 in dependence on the endo‐ and exocyclic ring heteroatoms (O, S, Se) are demonstrated by shift increments and discussed. In the unsaturated heterocycles linear dependences are observed for (i) 1H‐ and 13C‐NMR chemical shifts of the methine fragments in 4‐position and (ii) 13C chemical shifts of CS and CSe carbons in analoguous substituted compounds. The 13C absorptions of C‐2 are shifted to lower field in the series CO, CSe, CS (analoguous substituted compounds). This observation is not to understand by variations in the δE term of the 13C chemical shift but much better by changes in the electron density distribution.Die in den letzten Jahren zu beobachtende stürmische Entwicklung methodischer und apparativer Aspekte der NMR‐Spektroskopie schwerer Kerne ließ die 13C‐Kernresonanz zu einer Routine‐methode für die Strukturaufklärung in der organischen Chemie werden. Die 13C‐NMR‐Spektroskopie ist in dieser Hinsicht besonders leistungsfähig, da die 13C‐NMR‐chemische Verschiebung – der wichtigste Parameter dieser Methode – sehr empfindlich auf Strukturänderungen reagiert und diese Einflüsse häufig durch Inkremente beschrieben werden können. Da man bei der Signalzuordnung und Spektreninterpretation oft auf experimentelles Vergleichsmaterial angewiesen ist, kommt der Kenntnis von Zusammenhängen zwischen Molekülbau und Spektrenparametern eine allgemeine Bedeutung für die Strukturanalytik zu.
Zur Berechnung der mizellaren Aggregationszahl homologer und isomerer Alkansulfonate
Authors: Sowada Rudolf 
Published: December 2004

On the Calculation of Micellar Aggregation Numbers for Homologous and Isomeric Alkane SulphonatesBased on CHUJO's correlations the following equation is derived to calculate micellar aggregation numbers m for homologous and isomeric alkane sulphonates: log m = 0,713 + 0,085 · I · Fs · nCIt is shown that variation of the critical micelle concentration is not the only factor determining the m values of detergents. cM and m values for the unknown isomeric pentadecane sulphonates have been calculated.Detergents with functional groups in middle positions are of great interest due to very low m values besides low cM values.
Untersuchungen über die Autoxidation verzweigter Olefine. I, Autoxidation von 2‐Methylalk‐1‐enen und 2‐Methyalk‐2‐enen
Authors: Bilas W. , Pritzkow W. , Höbold W. 
Published: December 2004

Studies on the Autoxidation of Branched‐chain Olefins. I. Autoxidation of 2‐Methylalk‐1‐enes and 2‐Methylalk‐2‐enesThe products of the autoxidation of 2‐methylpent‐1‐ene, 2‐methylpent‐2‐ene, 2‐methylhex‐1‐ene, 2‐methylhex‐2‐ene, 2,4,4‐trimethylpent‐1‐ene, and 2,4,4‐trimethylpent‐2‐ene were analyzed by gas chromatography. The identification of the products corresponding to the individual peaks was possible by comparison with authentic substances or by preparative gaschromatographic separation and n.m.r.‐spectroscopy of the isolated samples. In this way not only the epoxides and the products of the oxidative cleavage of the CC‐double bond but also the allylic alcohols formed by LiAlH4‐reduction of the oxidation mixtures could be identified and analyzed. From the results the compositions of the original oxidation mixtures were calculated.
Massenspektroskopische Untersuchungen von 5‐halogenierten Pyrimidinglucuroniden
Authors: Mahrwald Rainer , Schwarz Wolfgang 
Published: December 2004

Mass Spectroscopy of 5‐Halogenated PyrimidinglucuronidesUsing the ion source according to von ARDENNE, useful spectra of negative and positive ions from sensitive glycosides were obtained either by electron attachment (EA‐) or low voltage electron impact (EI‐) mass spectroscopy.Spectra of glucuronides derived from 5‐halogenated uracil, 2‐thiouracil, 4‐thiouracil and 6‐mercaptopurin in their peracetylated, esterified and free acidic form are described. Most stable peracetylated 2‐ and 4‐thiouracil glucuronides reveal intensive peaks of molecule ions.The halogen‐carbon bonding strength, calculated from complementary aglycon peaks, demonstrates expected tendencies due to the halogen.
Zur Rolle von EDA‐Komplexen bei kationischen Polymerisationen. IX. Zum Lösungsmitteleinfluß auf Die Komplexbildung des kationischen Kettenendes mit Monomeren
Authors: Heublein G. , Spange S. 
Published: December 2004

On the Role of EDA‐Complexes in Cationic Polymerization. IX. The Solvent Influence on the Complex Formation of Monomeres with Cationic Chain EndThe influence of solvents on CT‐interaction of carbenium ions with aromatic bπ‐donors (substituted stilbenes, benzenes and naphthalenes), using stable carbenium ions salts as model compounds (triphenyl methyl hexachlorantimonate and tropylium tetrafluoroborate), has been investigated by spectroscopic, calorimetric and conductometric methods. These data as well as conclusions from thermodynamic measurements indicate that the complex formation to be a competetion of the bπ‐donor with the counterion and/or the solvent, depending on the degree of dissociation.
Imidazolidinderivate aus Oxalamidinen
Authors: Beckert R. , Mayer R. 
Published: December 2004

Derivatives of Imidazolidines from Oxalic AmidinesTetraarylsubstituted oxalic amidines 1 react with acyl chlorides, phosgene, thiophosgene, chlorocarbonylsulfenylchloride, isocyaniddichlorides, and N‐aroyl‐1‐chlorothio‐formimidoylchlorides 7 to give the corresponding 5‐membered heterocycles 3, 4, 5 and 8.Isocyanates 9 and isothiocyanates 10 react with oxalic amidines to yield imidazolidines 11, 12 and ureas 13, 14.Hydrolysis of 3–5, 8, 11, 12 leads to the corresponding oxo compounds 15, 16.
Untersuchung der sensibilisierten Photolyse von 2‐Diazo‐1‐oxo‐1,2‐dihydronaphthalenen in fester Schicht
Authors: Böttcher H. , Marx D. R. J. , Lukas J. , Strehmel B. 
Published: December 2004

Studies on the Sensitized Photolysis of 2‐Diazo‐1‐oxo‐1,2‐dihydronaphthalenes in Solid LayersThe photolysis of 5‐substituted 2‐diazo‐1‐oxo‐1,2‐dihydronaphthalenes can be sensitized by proper dyes as could be detected in various binders. Whereas the quantum yield of the direct photolysis is hardly influenced by the glass transition temperature Tg of the binder matrix the spectral sensitization is only effectiv in a rigid binder matrix (Tg > room temperature Tr). In deformable binders (Tg < Tr) and in solution, resp., the quantum yields of the spectral sensitization drastically decrease as a result of competing desactivation processes. The observed quenching of the direct and delayed dye fluorescence by o‐quinone‐diazides does not allow a clear determination of the spin multiplicity of the photolysis
Photochemie arylsubstituierter Δ2‐1,3,4‐Oxadiazoline. II. Zum Einfluß der Substituenten und des Lösungsmittels auf die Absorptions‐ und Fluoreszenzeigenschaften arylsubstituierter Δ2‐1,3,4‐Oxadiazoline
Authors: Csongár C. H. , Socher R. , Tomaschewski G. 
Published: December 2004

Photochemistry of Arylsubstituted Δ2‐1,3,4‐Oxadiazolines. II. The Influence of the Substituents and the Solvent on the Absorption and Fluorescence Properties of Arylsubstituted Δ2‐1,3,4‐OxadiazolinesThe electronic absorption and the fluorescence spectra of 16 arylsubstituted Δ2‐1,3,4‐oxadiazolines were measured in benzene at room temperature.The push‐pull effect of the substituents supports an increasing intramolecular charge‐transfer in the electronically excited singlet state, which increases its dipole moment relative to the ground state.The significant linear correlation of the Hammett σp‐values with the energies of the fluorescence and absorption maxima of the Δ2‐oxadiazolines, p‐substituted in the phenylring at the C 2‐atom, demonstrate these intramolecular charge transfer.The titel compounds demonstrate with increasing solvent polarity a bathochromic shift of the absorption maxima.For some oxadiazolines the dipole moment for the excited singlet state proved to be about 30 Cm as Stoke's shift dipendency from the solvent indicate.
Tetrathiafulvalene. XVI. Spektroskopische und elektrische Eigenschaften von TTF und TTF‐TCNQ‐Komplexen
Authors: Schukat G. , Fanghänel E. , Chyla A. 
Published: December 2004

Tetrathiafulvalenes. XVI. Spectroscopic and Electrical Properties of TTF and TTF‐TCNQ‐ComplexesUV‐vis‐spectra of mono‐ and dications of the TTF 2 show in comparison to those of TTF 1 and 3 that the aryl substituent in the TTF 2 is more twisted from the TTF‐plane than in 1 and 3. Absorption maxima of mono‐ and dications from TTF 1 and 3 lie at a significantly greater wavelength than absorption maxima of mono‐ and dications from TTF 2, because a better electronic interaction between substituents in the aryl‐group and the positively charged dithiolium‐ring is possible. TCNQ‐complexes of smoother TTF 3 also have a higher electrical conductivity than TCNQ‐complexes of 2.
Prostaglandine und Prostaglandinvorstufen. Oxydative Spaltung von Olefinen durch Ozonisierung und Oxydation im Lösungsmittelsystem Aceton/tert‐Butanol – eine Methode zur Gewinnung von substituierten Cyclopentylessigsäuren
Authors: Schick H. , Welzel H.‐P. , Schwarz S. , Truckenbrodt G. 
Published: December 2004

Prostaglandins and Prostaglandin Intermediates. Oxidative Cleavage of Olefins by Ozonization and Oxidation in the Solvent System Acetone/tert. Butanol – a Method for Preparation of Substituted Cyclopentyl Acetic AcidsOxidative cleavage of olefinic double bonds by ozonization in acetone in the presence of tert. butanol followed by oxidation with JONES' reagent in the same solvent system gives carboxylic acids and/or ketones in good yields. Acetic acid or water can be used instead of tert. butanol with the same success. This “one‐pot” procedure was developed in connection with the synthesis of intermediates for the preparation of 8‐methyl‐prostaglandin C2.
Zum Desaktivierungsverhalten photoangeregter Aryltropyliumionen. II. Fluoreszenzlöschung von Aryltropyliumionen
Authors: Abraham W. , Dreher B. , Buck K. , Kreysig D. 
Published: December 2004

About the Deactivation Behaviour of Photoexcited Aryltropyliumions. II. Fluorescence Quenching of AryltropyliumionsThe properties of aryltropyliumions in the excited singlet state were studied. These ions are very strong acceptors. So the fluorescence is quenched by aromatic donors. The rates of fluorescence quenching depend on the ionization potential of the donor. This fact is discussed in terms of mechanisms derived by WELLER et al. The results were related to the light stability of aryltropyliumions.
Nitromethylpyrazole aus 2‐Cyan‐3‐methylthio‐4‐nitrocrotonsäurederivaten
Authors: Schäfer H. , Gewald K. 
Published: December 2004

3‐Nitromethyl‐pyrazoles from 2‐Cyano‐3‐methylthio‐4‐nitrocrotonic Acid Derivatives2‐Cyano‐3‐methylthio‐4‐nitrocrotonic Acid Derivatives1a,breact with hydrazines to form the 5‐amino‐3‐nitromethyl‐pyrazoles2a–cand the 5‐nitromethyl‐pyrazol‐3‐one3respectively. Contrary to this carboxylic hydrazides attacks the nitro group. For the resulting products the structure of pyrrol‐2,5‐dione oximes4is proposed. On the similar way from 3‐methylthio‐4‐nitro‐2‐phenylcrotononitrile1cand phenylhydrazine the pyrrol‐2,5‐dione hydrazone5arises. Subsequent reactions of2yield 3‐nitromethyl‐pyrazole derivatives6, 3‐nitromethyl‐azinones8and nitromethyl‐pyrazolyl‐azo compounds10.
Kinetische Untersuchungen zur Pyrolyse von Mono‐n‐alkyl‐cyclohexanen
Authors: Zychlinski W. , Bach G. , Glauch B. , Zimmermann G. 
Published: December 2004

Kinetic Investigations of the Pyrolysis of Mono‐n‐alkyl‐cyclohexanesThe thermal decomposition of cyclohexane and six mono‐n‐alkylcyclohexanes was studied kinetically in a metallic laboratory tubular reactor at 650 to 850°C and atmospheric pressure.Kinetic parameters were found to be a function of length of the alkylic side chain. A comparison with analogous parameters of n‐paraffins and the unsubstituted cyclohexane allowed the conclusion that CC‐scission in the alkylic chain is the initial reaction in pyrolysis of n‐alkylcyclohexanes followed by radical attacks to all CH‐bonds of the feed molecules.