bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photochemie substituierter Cycloheptatriene. XII. Dualfluoreszenz von 1‐Aryl‐4‐(p‐dimethylaminophenyl)‐cycloheptatrienen
Authors: Abraham W. , Kupfer M. , Kreysig D. 
Published: December 2004

Photochemistry of Substituted Cycloheptatrienes. XII. Dual Fluorescence of 1‐Aryl‐4‐(p‐dimethylaminophenyl)‐cycloheptatrienesDiarylcycloheptatrienes 1 in solution show two fluorescences originating from two different excited states. The ratio of intensities of the two fluorescences depends on the excitation energy. Two alternatives are discussed as the origin of the dual fluorescence: conformers in the ground state or an adiabatic photoreaction, respectively. The two emissions are ascribed to different geometries of the seven‐membered ring. Despite the different excitation spectra the dual fluorescence of the compounds 1 is explained as an excited state property of a single absorbing species, and not as two ground state species giving rise to the two fluorescence bands.
Phosphororganische Antioxidantien. II. Kinetik und Mechanismus der Zersetzung von Alkylhydroperoxiden durch Esteramide der phosphorigen‐ und Phosphorsäure
Authors: Rüger C. , Arnold D. , Schwetlick K. 
Published: December 2004

Organophosphorus Antioxidants. II. Kinetics and Mechanism of the Decomposition of Alkylhydroperoxides by Esteramides of Phosphorous and Phosphoric AcidThe reaction mechanism of 2‐amido‐1,3,2‐benzodioxaphospholes (1) with cumyl and t‐butylhydroperoxide has been studied kinetically by means of 31P‐n.m.r. and e.p.r. spectroscopy and high pressure liquid chromatography. 1 reacts with cumyl hydroperoxide to give the corresponding 2‐oxides (2) which with more hydroperoxide and/or water form the phosphate esters 7 and 8. These acidic phosphates decompose cumyl hydroperoxide catalytically giving phenol and acetone.All amides (1) react with t‐butyl hydroperoxide stoichiometrically to give t‐butanol.The ionic mechanism of hydroperoxide decomposition is accompanied in a minor proportion by a homolytical one.
Semiempirical and ab initio Calculations on the Tautomerism of Pyrazolin‐5‐ones in the Gas Phase and in Solution
Authors: Krebs C. , Förster W. , Köhler H.‐J. , Weiss C. , Hofmann H.‐J. 
Published: December 2004

Semiempirische und ab initio Berechnungen zur Tautomerie von Pyrazolin‐5‐onen in der Gasphase und in LösungEs werden die Ergebnisse einer durchgehend theoretischen Behandlung der Tautomeriegleichgewichte von Pyrazolin‐5‐onen vorgestellt. Der Formalismus beinhaltet die Berechnung der potentiellen Energie mit Hilfe des MNDO‐, STO‐3G‐ und 4‐31 G‐Verfahrens, die statistisch‐thermodynamische Behandlung der Gleichgewichte unter Zugrundelegung des MNDO‐Kraftfeldes und die Abschätzung des Lösungsmitteleinflusses mit Hilfe verschiedener klassischer und quantenchemischer Reaktionsfeldmodelle.
Ionisation von Triphenylmethylbromid in Nitromethan
Authors: Heublein Günther , Bauerfeind Dietmar 
Published: December 2004

Ionisation of Triphenylmethylbromide in NitromethaneDissolving triphenylmethylbromide in nitromethane leads to the formation of HBr which complicates conductivity and spectroscopic measurements of carbenium ion absorption. As a result of addition of bromide ions (as tetraethylammonium bromide = Et4NBr) the triphenylmethylabsorption totally disappeares. It can be concluded that Ph3CBr in nitromethane is partially present in form of free (solvated) ions. The carbenium ion concentration has been determined as a function of gross concentration and temperature.
Zur Temperatur‐ und Viskositätsabhängigkeit der Fluoreszenzquantenausbeuten von donator‐substituierten 4′‐Diphenylphosphinyl‐trans‐stilbenen in wenig viskosen Lösungsmitteln unterschiedlicher Polarität
Authors: Gloyna D. , Alder L. , Repke D. 
Published: December 2004

The Dependence of Fluorescence Quantum Yields of Donor Substituted 4′‐Diphenylphosphinyl trans‐Stilbenes on Temperature and Viscosity in Low Viscous Solvents of Different PolarityThe dependence of fluorescence quantum yields of donor substituted 4′‐diphenylphosphinyl trans‐stilbenes 1 on temperature was investigated between 15–65°C in toluene and n‐propanol. It is concluded that the fluorescence quantum yield dependence on temperature is due to the dependence of nonradiative deactivation on solvent viscosity. The nonradiative deactivation is attributed to the ethylene bond rotation in 1. The rotation around the ethylenic bond and the fluorescence are the two most important deactivation processes detected up to now for the first excited singlet of 1 in liquid solution.
Umsetzung von α‐Cyano‐β‐aryl‐acrylsäure‐ethylestern mit Hydrazin, eine Retro‐Knoevenagel‐Reaktion
Authors: Geissler G. , Hippius M. , Tomaschewski G. 
Published: December 2004

Reaction of α‐Cyano‐β‐aryl Acrylic Acid Ethylesters with Hydrazine, a Retro‐Knoevenagel‐ReactionWe tried to obtain 4‐cyano 5‐aryl pyrazolidones‐(3) 3a, b and related azomethine imines 4a, b. However the reaction of α‐cyano β‐aryl acrylic acid ethylesters 2a, b with hydrazine yields the familiar cyano acetic acid arylidene hydrazides 5a, b by cleavage of the carbon‐carbon double bond. 5a, b react with pyrene‐1‐aldehyde to 7a, b. Formation of 5a, b is proved by an independent synthesis. 5a, b and 7a, b are investigated by mass spectrometry.
Synthese und Struktur neuer 1‐Imino‐1λ4,2,4,6‐thiatriazine
Authors: Fischer E. , Rembarz G. , Teller M. 
Published: December 2004

Synthesis and Structure of Novel 1‐Imino‐1λ4,2,4,6‐thiatriazinesO,O′‐Dimethyldiisobiurete 1 is cyclisized with N‐arylsulfonyl sulfinyl amines 4a–c to 1λ4,2,4,6‐thiatriazines 9a–c. The reaction with corresponding sulfur diimides 7a–c leads to identical 1λ4,2,4,6‐thiatriazines 9a–c. Methylation products from 9c with diazomethane are isolated by column chromatography. The cyclization mechanism with a substituted imido sulfurous diamide intermediate is discussed.
Eigenschaften und thermische Reaktionen von Komplexen der Arendiazoniumsalze mit Kronenethern
Authors: Becker H. G. O. , Israel G. , Kalauch Angelika , Pfeifer D. 
Published: December 2004

Properties and Thermal Reactions from Complexes of Arene Diazonium Salts with Crown EthersIn contrast to 18‐crown‐6, the substituted crown ethers Benzo‐18‐crown‐6, Dibenzo‐18‐crown‐6, and Naphtho‐18‐crown‐6 form in solution complexes with p‐CH3C6H4N2+BF4‐characterized by a broad charge transfer absorption up to 550 nm. The formation constants lg Kc are 2,32 2,16 and 1,44 for Benzo‐, Dibenzo‐, and Naphtho‐18‐crown‐6, respectively. Formation enthalpy ΔH = −7,5 kJ/mol and entropy ΔS = +18 J/K mol are measured in the case of p‐ClC6H4N2+BF4− and Dibenzo‐18‐crown‐6 (20°). Kc depends on substituents in the arene ring of the diazonium salt; ϱ = +0,8. Thermal dediazoniation in the presence of Crown ethers results in high yields of the corresponding arene. This is explained by a fast radical chain reaction between the diazonium salt and the polyether (Meerwein‐Reduction).
Zur Isomerisierung von Benzilphenylosazonen in Gegenwart von Säuren
Authors: Spassov A. W. , Christova N. I. 
Published: December 2004

Isomerisation of Benzilphenylosazones in the Presence of AcidsIsomerisation process of the three stereomeric benzilphenylosazones (Z,Z E,E and Z,E) in a melt of trichloracetic acid and in an ethylacetate solution of conc. sulfuric acid is studied. It is established that the convertion runs irreversibly to the stable E,E‐isomer at low acid concentration. The process is reversible at high acid concentration and the equilibrium state depends on this concentration.
Cyclisierungsreaktionen β,γ‐ungesättigter Kohlensäurederivate. VII. Synthese eindeutig N‐acylierter Thiazolidin‐2‐one und Oxazolidin‐2‐one
Authors: Widera R. , Mühlstädt M. 
Published: December 2004

Cyclization Reactions of β,γ‐Unsaturated Derivatives of Carbonic Acid. VII. Synthesis of Unequivocal N‐Acylated Thiazolidine‐2‐ones and Oxazolidine‐2‐onesA new synthetic route to N‐acylated thiazolidine‐2‐ones and oxazolidine‐2‐ones is reported: The reaction of carboxylic acid chlorides with 2‐alkoxy‐2‐thiazolines (1, 2) or ‐2‐oxazolines (3) yields unequivocal N‐acylated thiazolidine‐2‐ones (4–6) or oxazolidine‐2‐ones (7). Bifunctional acid chlorides, e.g. oxalyl chloride or thiophosgene yield compounds 11 and 12.
Über die Nitril‐Carboxamid‐Umlagerung und die Heterocyclenbildung aus 2‐Cyancyclohexenylharnstoff
Authors: Bischoff Christian , Schröder Edith 
Published: December 2004

The Nitrile Carboxamide Rearrangement and the Formation of Heterocycles via Cyano‐cyclohexenyl‐ureaAnthranilic amide and cyanogen bromide form Cyano‐phenyl‐urea (7) via Nitrile Carboxamide Rearrangement. Cyclisation of cyano‐cyclohexenyl‐urea (4) yields 4‐amino‐2,3,5,6,7,8‐hexahydroquinazolin‐2‐one (10). 4 and amines form N‐cyano‐cyclohexenyl‐N'‐alkyl‐ureas (11a–e) or 3‐alkyl‐4‐amino‐hexahydroquinazolin‐2‐ones (12a–g). 4 and α‐aminoacids yield octahydro‐imidazolo‐quinazolindiones (14a–b). Oxo‐cyclohexane‐2‐carboxamide (1) and amino benzimidazole form hexahydrobenzimidazo‐quinazolinone 17.
On the Interpretation of the Solvent Influence on Spectroscopic and Photophysical Parameters by means of multiparameter models
Authors: Kupfer M. , Abraham W. 
Published: December 2004

Zur Interpretation des Lösungsmitteleinflusses auf spektroskopische und photophysikalische Parameter mittels MehrparametermodellenDie Anwendung von Mehrparametermodellen nach Kamlet und Taft auf die Solvatochromie von Absorption und Fluoreszenz sowie auf photophysikalische Parameter wird durch Beispiele aus der Literatur und durch eigene Beispiele demonstriert.Dabei werden besonders spezifische Wechselwirkungen zwischen Substrat und Lösungsmittel diskutiert. Mit Hilfe der Regressionskoeffizienten von multiplen Korrelationen lassen sich Beziehungen zwischen der Struktur der Substrate und dem Ort der spezifischen Wechselwirkungen herstellen.Die Beschreibung dynamischer Prozesse gelingt mit der Einführung eines zusätzlichen Viskositätsparameters, der auf der scheinbaren Arrheniusschen Aktivierungsenergie der Lösungsmittelviskosität beruht.
Elektrochemie organischer Kationen. Arylsubstituierte Tropyliumsalze
Authors: Dreher B. , Abraham W. , Pragst F. 
Published: December 2004

Electrochemistry of Organic Cations. Arylsubstituted Tropylium SaltsThe electrochemical behaviour of some mono‐ and diarylsubstituted tropylium perchlorates in acetonitrile was investigated and is discussed in connection with their u. v.‐vis absorption spectra.
Festphasensynthese von Oligodesoxyribonucleotiden an Polystyren‐Teflon‐Trägern nach der Diestermethode
Authors: Birch‐Hirschfeld E. , Weiss R. , Rosenthal A. , Cech D. 
Published: December 2004

Phosphodiester Solid Phase Synthesis of Oligodeoxyribonucleotides on Polystyrene‐Teflon‐SupportsPhosphodiester solid phase method on two different polystyrene‐teflon‐supports has been applied for for the rapid synthesis of the hexanucleotides d(TCTAGA), d(TGTCAA), d(TTGACA) and the octanucleotides d(CATTATAC) and d(GTATAATG)Als Abkürzungen für die Nucleinsäurebausteine und deren Schutzgruppen wurden die von der IUPAC‐IUB Commission on Biochemical Nomenclature (CBN) empfohlenen Regeln verwendet, vgl. Hoppe‐Seyler's Z. Physiol. Chem. 351, 1055 (1970); außerdem wurden abgekürzt:DEAE = O‐(Diethylamino)ethyl, HPLC = Hochdruckchromatographie, O.D.E. = optische Dichteeinheit [17], TEAB = Triethylammoniumbicarbonat, TFA = Trifluoressigsäure, Tris = α,α,α‐Tris‐(hydroxymethyl)‐methyl‐amin

, respectively. In the case of hexanucleotides a polymeric support with 90 mg polystyrene/g support has been used. The octanucleotides were prepared using a 180 mg polystyrene/g support. The yields of all oligonucleotides were 42–51%/condensation step.
Komplexchemisches Verhalten von N‐substituierten 2‐(oHydroxyphenyl)‐Δ2‐imidazolinen als Metallextraktionsmittel
Authors: Beger J. , Wagner G. , Dinjus U. , Görls H. , Uhlig E. , Sieler J. 
Published: December 2004

The Coordinative Behaviour of N‐Substituted 2‐(Δ2‐Imidazolin‐2‐yl)‐phenols as Metal ExtractantsN‐Substituted 2‐(Δ2‐imidazolin‐2‐yl)‐phenols (R4NNOH) are obtained by the reaction of N‐alkyl diaminoethane‐1, 2 and 2‐hydroxybenzoic acid esters. In contrast to many other copper(II) complexes with the donor set N2O22−(A), the species Cu(R4NNO)2(B) are easily soluble in nonpolar solvents. The reason is the monomeric square‐planar structure of B, which differs from the polymeric distorted octahedral structure of A.The two maxima in the vis‐spectra of Cu(R4NNO)2 and Ni(R4NNO)2 are assigned to the 3 dxy → 3 dx2‐y2 and the 3 dxz, 3 dyz → 3 dx2‐y2 electron transitions. The shift of these maxima, which is connected with the dissolution in chloroform, is explained by the formation of hydrogen bonds between the solvent and the N‐alkylated nitrogen atoms of the ligands.1H‐n. m. r.‐spectra and solubility of the ligands and the crystal structure of Cu[(C4H9)NNO]2 are described.
Desaktivierungsverhalten von Arenen und Heteroarenen. XXXVI. Zum Lösungsmittel‐ und Temperatureinfluß auf das Desaktivierungsverhalten von 9, 9′‐Bis(acridizinium‐yl) bei hohen Konzentrationen
Authors: Bendig J. , Helm S. , Kreysig D. , Schmidt H. 
Published: December 2004

Deactivation Behaviour of Arenes and Heteroarenes. XXXVI. The Solvent and Temperature Dependence of Deactivation Behaviour of 9, 9′‐Bis(acridizinium‐yl) at High ConcentrationAt room temperature the geometrical structure of the fluoresceing singlet state of 9, 9′‐bis(acridizinium‐yl) is determined by the solvent. In solvents of the type A (water, methanol, acetonitril) a plain S1‐state emits, in the case of the solvent type B (ethanol, propanol‐(2)) the S1‐state is twisted. Both excited states have different emission spectroscopical properties.At high concentration (c ≥ 10−4 mol l−1) in the case of the solvent type B a new emission band is observed, and the monomer emission is quenched. This new band is interpreted as a fluorescence from a molecular associate in the excited state. The intensity of this associate band is increasing with decreasing temperature. It is shown that this band is the result of molecular association in the ground state. From the photochemical irradiation it follows that only in the case of the solvent type B a photocycloaddition is possible. The plain S1‐state does not react.
Stereochemische Untersuchungen heterocyclischer Verbindungen. XII. Kristall‐ und Molekülstruktur von 1‐(2‐Amino‐1‐cyano‐2‐thio‐ethylen)pyridiniumyliden
Authors: Fischer E. , Knippel M. , Wollin K.‐M. , Kálmán A. , Argay Gy. 
Published: December 2004

Stereochemical Investigations of Heterocyclic Compounds. XII. Structural Investigations of 1‐(2‐Amino‐1‐cyano‐2‐thio)ethene Pyridinium YlidesTwo isomerization processes were found by 1H‐d‐n. m. r. characterized by ΔG* = 67 ± 4 KJ/mol for E‐ Z‐isomerization and ΔG* = 46 ± 5 KJ/mol for the hindered rotation of the pyridine substituent in 1a. The structure of 1b was solved by direct method. Crystals are monoclinic space group P21/n, a = 13.682(3), b = 9.452(1), C = 19.713(6) Å, β = 96.42(2)°, V = 2533.3 Å3, Dx = 1.328 Mg · m−3, Z = 8. Both E‐ and Z‐isomeres of 2b are found in the crystal lattice. The aminoC distance with 1.369 (1,387) Å is shorter than the theoretical single bond distance. The formal CC double bond with 1.377 (1.391) Å is considerably longer than 1.337 Å observed in the some alkenes.
The Electrochemical Synthesis of Benzindoles from aminonaphthalenes in the presence of arsonium ylide
Authors: Rastogi Ravi , Zutshi Kamala 
Published: December 2004

Die elektrochemische Synthese von Benzindolen aus Aminonaphthalenen in Gegenwart von ArsoniumylidenDie elektrochemische Synthese von 2‐Aryl‐1 H‐benz[g]indolen (3a–c) und 2‐Aryl‐3 H‐benz[e]indolen (4a–c) aus methanolischer Lösung von 1‐ oder 2‐Aminonaphthalenen in Gegenwart von kathodisch gebildeten Arsoniumyliden (2a–c) wird beschrieben.Die optimalen Synthesebedingungen werden diskutiert.magnified image
13C‐NMR‐Spektroskopie von bromierten 3‐Keto‐ und 3β‐Acetoxy‐5α‐cholestan‐Verbindungen
Authors: Römer J. , Scheller D. 
Published: December 2004

13C‐NMR Spectroscopic Investigations of Brominated 3‐Keto‐ and 3β‐Acetoxy‐5α‐cholestane DerivativesThe chemical shifts of some brominated 3‐keto‐ and 3β‐acetoxy‐5α‐cholestane derivatives are determined. The substituent effects of bromine atoms on chemical shifts (SCS) and their additive behaviour, especially γ‐SCS, are discussed.
Analytische Probleme der Reaktion zwischen polymergebundenen Phosphinen und Methyliodid
Authors: Paetzold E. , Oehme G. , Pracejus H. 
Published: December 2004

Analytical Problems of the Reaction between Polymer Supported Phosphino Groups and Methyl IodideA series of different crosslinked styrene‐divinylbenzene‐copolymers bearing diphenyl phosphinomethyl groups was reacted with methyl iodide in ethanol. The quaternization has been controlled by elementary analysis of P and I and by ir spectroscopy using a key band at 1123/cm. The spectroscopic method gave satisfactory results with sample amounts of 5 mg polymer in KBr discs. In resins containing up to 7% divinylbenzene the methylation was almost quantitative within 1 h refluxing. However, in highly crosslinked polymers ( > 10% DVB) containing residues of free chloromethyl groups and intraresin quaternized phosphino groups we observed side reactions in boiling ethanol. These could be avoided by performing the methylation in toluene at room temperature.
3‐Amino‐thieno[2,3‐b]furane und 3‐Amino‐thieno[3,2‐b]furane
Authors: Gewald K. , Bellmann P. 
Published: December 2004

3‐Amino‐thieno[2,3‐b]furans and 3‐Amino‐thieno[3,2‐b]furansThe O‐alkylation of 2‐hydroxy‐thiophene‐3‐carbonitriles (1) with α‐bromocarbonyl compounds yields the 2‐alkoxy‐thiophene‐3‐carbonitriles (2a–f) among them 2‐benzoylmethoxy‐thiophene‐3‐carbonitriles (2a–c) which undergo Thorpe‐Ziegler‐cyclization to form the 3‐amino‐2‐benzoyl‐thieno[2,3–b]furans (3) in low yields. The 2‐acyl‐3‐amino‐thieno[3,2–b]furans and ethyl 3‐amino‐thieno[3,2–b]furan‐2‐carboxylates (6) are synthesized in similar manner from 3‐hydroxy‐thiophene‐2‐carbonitriles (4) and α‐halogencarbonyl compounds via 3‐acylmethoxy‐ and 3‐ethoxycarbonylmethoxy‐thiophene‐2‐carbonitriles (5) with high yields.
Reactions of [2.2]paracyclophanes in melts. I. Reaction of [2.2]Paracyclophane‐4,5,12,13‐tetra‐carboxylic Acid Dianhydride with phenylacetic acid and N‐aryl carbamates
Authors: Mourad Aboul‐Fetouh E. , Nour‐El‐Din Ahmed M. 
Published: December 2004

Reaktionen von [2.2]Paracyclophanen in Schmelzen. I. Reaktion von [2.2]Paracyclophan‐4,5,12,13‐tetracarbonsäuredianhydriden mit Phenylessigsäure und N‐ArylcarbamatenThe parent hydrocarbon [2.2] paracyclophane (1) exhibits transanular electronic interaction and the two benzene rings behave as dependent π system towards the chemical reactions [1a–c]. We wish to study the effect of transanular electronic interaction on the chemical behaviour of the an hydride moity in 2[2a–d]. It has been reported that 2 is less reactive in comparison with phthalic anhydride, since an attempted conversion of 2 into a tetraester failed [2b] magnified imageThe reaction in melts between phtahlic anhydride, pryomillitic acid dianhydride (3) and carbamates yields the corresponding imides [3].
Kinetische Untersuchungen über die Autoxidation von Olefinen
Authors: Futu‐Tangu M. , Lawson E. , Pritzkow W. , Voerckel V. 
Published: December 2004

Kinetic Studies on the Autoxidation of OlefinsThe oxidabilities \documentclass{article}\pagestyle{empty}\begin{document}$ {{{\rm k}_{\rm p} } \mathord{\left/ {\vphantom {{{\rm k}_{\rm p} } {\sqrt {2{\rm k}_{\rm t} } }}} \right.\kern-\nulldelimiterspace} {\sqrt {2{\rm k}_{\rm t} } }} $\end{document} at 50°C were determined for 37 olefins, using chlorobenzene as the solvent and azodiisobutyronitril as the initiator. In the group of acyclic aliphatic olefins the oxidability rises with increasing number of alkyl groups bound to the double bond. This is also true for cyclic olefins, but in this case the ring size has also a great influence on the oxidability. So the oxidability decreases from five‐ring to eight‐ring cycloolefins. Particularly high oxidabilities are found in the case of olefins in which a phenyl group is attached directly to the CC‐double bond.
Partialsynthesen von Cardenoliden und Cardenolid‐Analogen. VIII. Lactonring‐alkylierte Cardenolide
Authors: Streckenbach Barbara , Franke Peter , Hintsche Rainer , Portius Hans Joachim , Repke Kurt R. H. 
Published: December 2004

Partial Syntheses of Cardenolides and Cardenolide Analogues. VIII. Lactone Ring‐Alkylated CardenolidesBase‐catalyzed alkylation of digitoxigenin (1), digitoxin (2), digoxigenin (3), and gitoxigenin‐3,16‐diacetate (4) with allyl bromide, allyl chloride or n‐propyl bromide in DMF resulted in the formation of the 22‐allyl‐, 21ξ,22‐diallyl‐, 22‐propyl‐, and 21ξ,22‐dipropyl‐derivatives 5–14, respectively.The determination of the molecular biological activity of the derivatives yielded valuable information.
Zur Zuordnung der 13C‐NMR‐Spektren von Steroiden mit A,B‐ und C,D‐trans‐ und ‐cis‐verknüpften Ringen Eine Anwendung der „attached proton test”︁‐Technik zur Baugruppenanalyse
Authors: Zeigan D. , Radeglia R. , Engelhardt G. 
Published: December 2004

On the Assignment of the 13C‐N.M.R. Spectra of Steroids with A,B‐ and C,D‐trans‐ and cis‐Joined Rings. An Application of the Attached Proton Test Technique to the Analysis of Building GroupsA modified single‐pulse attached proton test technique is used for an unequivocal assignment of the 13C‐n.m.r. signals to the building groups CHn (n = 0,1,2,3) of the steroid skeleton of 5α‐ and 5β‐cholestane as well as 14α‐ and 14β‐estratriene‐3‐methylether. It is shown that the different γ‐effects of selected carbon atoms of steroids with cis‐ and trans‐connected rings open a simple way to ascertain the configuration of the ring connection.
Formylation Products of Thioamides. IV. Reactions of 3‐Dialkylamino‐ and 3‐Hydroxythioacrylamides with Amines ‐ Synthesis of 3‐Aminothioacrylamides, 5‐Aminopyrazoles and 3‐Aminoisothiazolium Salts
Authors: Liebscher Jürgen , Areda Alemayehu , Abegaz Berhanu 
Published: December 2004

Formylierungsprodukte von Thioamiden. IV. Reaktionen von 3‐Dialkylamino‐und 3‐Hydroxythioacrylamiden mit Aminen – Synthese von 3‐Aminothioacrylamiden, 5‐Aminopyrazolen und 3‐Aminoisothiazoliumsalzen3‐Hydroxythioacrylsäureamide (5) oder 3‐Dialkylaminothioacrylsäureamide (4) bzw. deren Salze (3) werden von Aminen oder Hydrazinen leicht in 3‐Position unter Substitution angegriffen, wobei 3‐Aminothioacrylsäureamide (6) gebildet werden. Über die Zwischenstufe der 6 sind in Abhängigkeit vom Substituenten in 3‐Position entweder durch Oxydation 5‐Aminoisothiazoliumsalze (7) oder durch intramolekularen nucleophilen Angriff am Kohlenstoffatom 1‐Aminopyrazole (10) erhältlich.
Über die Pyrolyse von Pent‐1‐en‐4,4,5,5,5‐d5
Authors: Kopinke F.‐D. , Bach G. , Ondruschka B. , Zimmermann G. 
Published: December 2004

On the Pyrolysis of Pent‐1‐ene‐4,4,5,5,5‐d5The distribution of deuterium in the main products of thermal decomposition of pent‐1‐ene‐4,4,5,5,5‐d5 at 550 to 650°C was studied and interpreted. The results include conclusions on kinetic isotope effects, on relative reactivities of different C‐H‐bonds, on the proportion of terminal and nonterminal addition of methyl radicals, and on the importance of a radical isomerisation reaction. It was shown that the molecular decomposition (Retro‐En‐Reaction) cannot successfully compete with the radical way in the temperature range above 600°C
1H‐NMR‐spektroskopische Untersuchungen an substituierten Crotonsäure‐ und Dithiocrotonsäureestern
Authors: Michalik M. , Kreutzmann J. 
Published: December 2004

1H‐NMR Spectroscopical Investigations on Substituted Crotonates3‐Amino‐2‐cyanocrotonates 2 and ‐dithiocrotonates 3 have been characterized by n.m.r. spectroscopy. The data obtained are compared with those of acrylates 1. The COOR and CSSR groups are investigated with respect to their electron withdrawing effect and formation of intramolecular hydrogen bonds.