bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kristallin‐flüssige Bis‐[trans‐4‐n‐Alkylcyclohexancarbonsäure]‐hydrochinonester
Authors: Deutscher H.‐J. , Körber M. , Altmann H. , Schubert H. 
Published: December 2004

Liquid Crystalline Hydroquinone Bis‐[trans‐4‐n‐Alkylcyclohexane]‐carboxylatesThe synthesis of methyl‐, ethyl‐, chloro‐, bromo‐, cyano‐ and methoxy‐substituted esters of hydroquinone 1–7 and their mesomorphic properties are described. The title substances exhibit a large range of mesophases and clearing points about 40–50°C higher than that of the analogous esters of benzoi cacids. 4‐Benzoyloxyphenyl trans‐4‐n‐alkylcyclohexanecarboxylates 8–11 show nematic properties.
Nucleophile Substitutionen an Kohlensäurederivaten. XII. Kinetik und Mechanismus der Reaktion von N‐Nitro‐N‐alkylurethanen mit primären aliphatischen Aminen
Authors: Bacaloglu R. , Prodan‐Deac Y. , Csunderlik C. , Csomos P. 
Published: December 2004

Nucleophilic Substitutions to Carbonic Acid Derivates. XII. Kinetics and Mechanism of the Reaction of N‐Nitro‐N‐alkyl‐urethanes with Primary Aliphatic AminesThe aminolysis of N‐alkyl‐N‐nitrourethanes takes place, as the kinetical studies demonstrate, by means of several consecutive steps.The nucleophilic attack of the amine (first step; reaction B), as well as the proton‐transfere (second step; reaction C), are quick pre‐equilibres, followed by the slow, rate‐determining elimination of the nitramino‐group (reaction D).During the deprotonation, an intermediate with two to the nitramino‐group antiperiplanar orbitals is formed, providing the necessary mesomeric assistance of the elimination.
Darstellung und Reaktionen von 2‐Arylazo‐2‐nitro‐keten‐aminalen
Authors: Schäfer H. , Gewald K. 
Published: December 2004

Synthesis and Reactions of 2‐Arylazo‐2‐nitro‐keten AminalsN,N′‐Disubstituted 1‐nitro‐2,2‐diamino ethylenes 1 undergo azo‐coupling to form the title compounds 2. Their treatment with oxalyl chloride yields the imidazolidin‐4,5‐dione‐derivatives 4. 2 react with phosgene and thiophosgene to form 6‐nitro‐2,4‐diaryl‐5‐arylimino−2,3,4,5‐tetrahydro‐1,2,4‐triazin‐3‐ones 5 and ‐thiones 6 respectively. From 2 and N‐(dichloromethylene)‐arylsulfoamides the 6‐nitro‐2,4‐diaryl‐5‐arylimino‐3‐aryl‐sulfonylimino‐2,3,4,5‐tetrahydro‐1,2,4‐triazines 7 arise. The reduction of 2 yields the substituted oxalic amidines 9
Die Darzens‐Reaktion mit Thiazolaldehyden
Authors: Chiorean V. , Mager S. , Fârcâşan V. , Silberg A. 
Published: December 2004

The Darzens Reaction with ThiazolaldehydesThe reaction of formyl‐phenyl‐thiazoles 3–9 with ω‐chloracetophenone 1 and p‐nitrobenzyl chloride 2 was studied. It is shown that the Darzens reaction occurs easily with the 4‐formyl derivates. There is some competition by the Cannizzaro reaction. The structure of isomers 16Z and 16E was established by 1H‐n.m.r. spectroscopy.
Konduktometrische und spektroskopische Untersuchungen der Wechselwirkung von Lewis‐Säuren mit Halogenkomplexen
Authors: Heublein Günther , Grimmer Cornelia , Spange Stefan 
Published: December 2004

Conductometric and Spectroscopic Investigations of the Interaction of Lewis Acids with Halide ComplexesThe interaction of counter ions with Lewis acids has been investigated using mode systems of the type (C6H5)3C⊕ MXn+1⊖ (M = Sb, As, B, Fe; X = Cl, F) by means of conductometrical and UV‐spectroscopic methods. The changes of conductivity were strongly dependent on the nature and concentration of the Lewis acid. The results point to 1:1‐complexes between Lewis acids and counter ions. The behaviour was found to be complicated by dissoziation resp. assoziation processes. Ligand exchange reactions between Lewis acid and counter ion have also been found.
Organische Phosphorverbindungen. XIII. Reaktion vinyloger Chlormethylenimmoniumsalze mit Phosphorigsäuretrialkylestern
Authors: Schneider Peter , Fischer Gerhard W. 
Published: December 2004

Organic Phosphorus Compounds. XIII. Reaction of Vinylogous Chloromethylene Immonium Salts with Trialkyl Phosphites3‐Chloropropenylidene immonium salts of the type ClCArCHCHNMe2⊕X⊖ don't react like chloromethylene immonium salts ClCHNMe2⊕X⊖ with trialkyl phosphites according to the classical MICHAELIS‐ARBUSOV principle (RO)3P + R′Cl → (RO)2P(O)R′ + RCl but lead to salts of 1‐dimethylaminophosphonates (RO)2P(O)CH(NMe2 · HX)CHCClAr the structure of which is confirmed by two independent syntheses. Some characteristic reactions of the free dimethylaminophosphonates are described.
Synthesen von trail‐Pheromonen der Pharaoameise (Monomorium pharaonis(L.))
Authors: Schmitz Ernst , Sonnenschein Helmut , Gründemann Christel 
Published: December 2004

Syntheses of trail Pheromones of the Pharao Ant (Monomorium pharaonis (L.))Hofmann‐Löffler‐reaction, starting from 5‐amino‐tridecane yields pyrrolidine mixtures containing 2‐butyl‐5‐pentyl‐pyrrolidine 1, known as a trail pheromone of the Pharao ant. An analogous reaction of 7‐amino‐pentadecane leads to 2‐hexyl‐5‐pentyl‐pyrrolidine 2 as a mixture with an isomer. Definite 2,5‐dialkyl‐pyrrolidines are obtained by Seebach alkylation from N‐nitroso‐pyrrolidines e.g. 1, 2 or 3, the latter with an unsaturated side chain. Change of reaction conditions led to 2,2‐dialkyl‐pyrrolidines. Dehydrogenation followed by hydrogenation converts a mixture of cis‐trans‐isomers of 1 into definite cis‐compound 1a. Trails of these pyrrolidines are followed by Pharao ants.
Dreikomponentenreaktionen. VIII. Chlorierung von Olefinen in N‐Methylpyrrolidon
Authors: Beger J. , Jacobi R. , Storch A. , Ullmann M. 
Published: December 2004

Three‐Component Reactions. VIII. Chlorination of Olefines in N‐MethylpyrrolidoneThe chlorination of cyclohexene, styrene and 1‐dodecene in NMP gives immonium‐chlorides 5 reacting with water to β‐chloralkyl‐γ‐N‐methylaminobutyrat‐hydrochlorides. With cyclohexene the reaction proceeds stereospecifically as trans‐addition. From styrene there is only formed the Markovnikov product, and from dodecene a mixture of isomeres is obtained containing about 30% of the anti‐Markovnikov product.
Zersetzung von tert.‐Butyl‐ und Cumenhydroperoxid in Gegenwart von Übergangsmetallkomplexen
Authors: Ivanov S. K. , Kateva J. , Dahlmann J. , Höft E. 
Published: December 2004

Decomposition of t‐Butyl‐ and Cumene Hydroperoxide in Presence of Transition Metal ComplexesThe kinetics of the decomposition of t‐butyl hydroperoxide and cumene hydroperoxide in the presence of Co‐, Mn‐, Mo‐, Rh‐, Ir‐ and Pt‐complexes were investigated. By means of the inhibitor‐method it was shown, that these metal‐catalysed decompositions give mainly molecular products and no free‐radicals.
Eine einfache Synthese von Analoga des 8‐Aza‐D‐homo‐estrans
Authors: Moiseenkov A. M. , Rozhkov E. N. , Strakov A. Ya. 
Published: December 2004

A Simple Synthesis of 8‐Aza‐D‐homo‐estrane Analogs8‐Aza‐D‐homo‐estrane analogs containing the angular methyl group at C‐13 have been prepared by one step synthesis starting from 4‐acetyl‐4‐methylcyclohex‐2‐enone and 3,4‐dihydroisoquinolines.
The Behaviour of 4,5‐Dihydropyridazin‐3(2H)‐one Derivatives towards Organometallic Compounds
Authors: Fateen A. K. , Ismail M. F. , Kaddah A. M. , Shams N. A. 
Published: December 2004

Zum Verhalten von 4,5‐Dihydropyridazin‐3(2H)‐on‐Derivaten gegenüber organometallischen VerbindungenPhenyllithium reagiert mit 6‐Aryl‐ und 6‐Aryl‐4‐phenyl‐4,5‐dihydropyridazin‐3(2H)‐onen (1) unter 1,2‐Addition an die Azomethin‐Bindung zu Verbindungen des Typs 2.N‐Phenylderivate dieser Pyridazinone reagieren mit Phenyllithium oder Phenylmagnesiumbromid analog 6, während N‐Methylderivate mit diesen Reagenzien zu den Pyridazinderivaten 10 reagieren. Die Struktur der Produkte wird durch IR‐Spektroskopie und unabhängige Synthese gestützt.
Zur Darstellung und Charakterisierung von Vinylsenfölen
Authors: Schulze K. , Richter F. , Weisheit R. , Krause R. , Mühlstädt M. , Mühlstädt M. 
Published: December 2004

Synthesis and Characterisation of VinylisothiocyanatesThe preparation of vinylisothiocyanates by treatment of γ‐chloroallylchlorides with KSCN followed by rearrangement of the γ‐chloroallylthiocyanates is described. The structure is proved by the reaction of the vinylisothiocyanates with mercaptides and by spectroscopic methods.
Molecular geometry and excited electronic states. III. Theoretical Study on Excited State Geometry and Fluorescence Properties of Fluoranthene
Authors: Sühnel J. , Kempka U. , Gustav K. 
Published: December 2004

Molekülgeometrie und angeregte Elektronenzustände. III. Theoretische Studie zur Geometrie angeregter Elektronenzustände und zu den Fluoreszenzeigenschaften von FluoranthenEs wurde die Gleichgewichtsgeometrie des Fluoranthens in den Sn‐Zuständen (n = 0, 1, 2, 3, 4) durch Minimisierung der Gesamtenergie bezüglich aller Molekülkoordinaten berechnet. Fluoranthen ist in allen untersuchten Elektronenzuständen planar, zeigt aber bei Elektronenanregung bemerkenswerte änderungen der Bindungslängen. Unter Verwendung dieser Geometriedaten werden das Absorptionsspektrum und die Fluoreszenz aus dem tiefsten und aus höher angeregten Zuständen interpretiert. Die ungewöhnlich große Stokessche Verschiebung kann ohne Annahme eines nichtplanaren S1‐Zustandes verstanden werden. Ihre Größe nimmt mit zunehmender Energie von Sn ab.
Dienoligomerisierung. XVI. Nickelkomplexkatalysierte Codimerisierung von isomeren Octatrienen mit Ethen
Authors: Füllbier H. , Gaube W. , Lange R. , Tarnow M. 
Published: December 2004

Dienoligomerization. XVI. Catalytic Codimerization of Isomeric Octatrienes with Ethene by Nickel ComplexesThe isomeric octatrienes (n‐octa‐1,3c,t,7‐triene 1, n‐octa‐1,3c,6t‐triene 2 and 3‐methylhepta‐1,4t,6‐triene 3), which are easily obtained in high yields by transition metal catalysed dimerization of butadiene, react with ethene 4 in the presence of the cationic tetrakis‐(triethylphosphite)‐nickelhydride complex 5 to the dodimers 3‐methylnona‐1,4c,t,8‐triene 6, 4‐vinylocta‐2c, 7‐diene 7, 3‐methyl nona‐1,4c,t,7t‐triene 8, 4‐vinylocta‐2c,6t‐diene 9, 3,6‐dimethylocta‐1,4c,t,7‐triene 10 and 3‐methyl‐4‐vinylhepta‐1,5c‐diene 11. The concentration‐time dependence and a possible reaction mechanism of the codimerization are discussed and the structure data of the reaction products are reported.
Zur Kenntnis der katalytischen Dimerisation von Acrylsäurederivaten mit Hilfe von Palladium‐Komplexen. III. Reaktionen von β‐Palladioacrylestern und deren Beziehung zur Katalytischen Reaktion
Authors: Oehme G. , Pracejus H. 
Published: December 2004

On the Knowledge of the Catalytic Dimerization of Acrylic Acid Derivatives by Palladium Complexes. III Reactions of β‐Palladio Acrylates and Their Relation to the Catalytic ReactionComplexes of the type L2PdCl(CH  CHCOOCH3) (L2 = 2 PPh3 or Ph2PCH2CH2PPh2) were decomposed to dimethyl muconate by pyrolysis or by substraction of the phosphine ligands with (CH3CN)2PdCl2 in acetonitrile. The last mentioned reaction gave Δ3‐dimethyl dihydromuconate in the presence of hydrochloric acid. Δ3‐Dimethyl dihydromuconate was also formed by decomposition of (Ph2PCH2CH2PPh2) PdCl (CH  CHCOOCH3) with HBF4 in acetonitrile, but the analogous reaction in methyl acrylate as solvent gave Δ2‐dimethyl dihydromuconate. Thus, we have simulated the formation of the two main products of the catalytic dimerization of methyl acrylate with palladium(II)chloride in a stoichiometric manner. Mechanisms with hydride and carbene intermediates are discussed.
Propellanes. III. Use of 1,1,2,2‐Tetrabromomethylcyclopropane for Preparation of (6.6.1)Propellanes — 3,6,10,13‐tetrathia(4,5,11,12‐dibenzo)‐(6.6.1)propellane
Authors: Jamrozik Janusz 
Published: December 2004

Propellane. III. Verwendung des 1,1,2,2‐Tetrabrommethylcyclopropans zur Darstellung von (6.6.1)Propellanen — 3,6,10,13‐Tetrathia(4,5,11,12‐dibenzo)‐(6.6.1)propellanDurch Reaktion des 1,1,2,2‐Tetrabrommethylcyclopropans mit 1,2‐Benzoldithiol wurde die tricyclische Verbindung 1 mit Propellan‐Struktur erhalten. Die Struktur dieser Verbindung wurde mit Hilfe spektroskopischer Daten und massenspektroskopischer Fragmentierung ermittelt. Für das Propellan 1 werden zwei Konformationen (mit koplanarer und nichtkoplanarer Lage der Benzolringe) bei einer „twist‐tub”︁ Konformation der achtgliedrigen Ringe vorgeschlagen.
Electrophilic substitution in the azafluorenone systems — bromination of azafluorenones
Authors: Młochowski Jacek , Szulc Zdzisław 
Published: December 2004

Elektrophile Substitution in Azafluorenonsystemen ‐ Bromierung von AzafluorenonenDie Bromierung von 1‐ und 4‐Aza‐ und 1,5‐, 1,8‐ und 4,5‐Diazafluorenonen 1–5 mit N‐Bromsuccinimid, Brom in Schwefelsäure oder mit Brom 60proz. Oleum wurde als Modellreaktion für die elektrophile Substitution in Azafluorenon‐Systemen untersucht. Die Bromierung von Monoazafluorenonen mit N‐Bromsuccinimid in Schwefelsäure und Diazafluorenonen mit Brom in 60proz. Oleum ist eine günstige Methode zur Darstellung von bisher unbekannten Bromazafluorenonen. Die Strukturen der erhaltenen Bromderivate wurden mit Hilfe der 1H‐NMR‐Spektroskopie festgestellt. Die Ergebnisse der Substitution wurden in Abhängigkeit von der elektronischen Struktur der Azafluorenon‐Systeme diskutiert.
Partialsynthesen von Cardenoliden und Cardenolid‐Analogen. II. Synthese von Cardenolid‐analogen γ‐Steroidyl‐butenoliden
Authors: Theil Fritz , Lindig Claus , Repke Kurt 
Published: December 2004

Partial Syntheses of Cardenolides and Cardenolide Analogues. II. Synthesis of Cardenolide‐Analogous γ‐Steroidyl‐ButenolidesThe synthesis of the cardenolide‐analogous stereoisomeric γ‐steroidyl‐butenolides 5 and 6 and of the γ‐steroidyl‐α‐methyl‐butenolide 13, starting from β‐ketosulfoxide 3 by alkylation with methyl bromoacetate and methyl α‐bromopropionate, respectively, followed by the sodium borohydride reduction of the alkylated intermediates is described. 1,3‐dipolar addition of diazomethane to 5 followed by pyrolysis of butyrolactone‐pyrazoline‐adduct 11 yields γ‐steroidyl‐β‐methyl‐butenolide 10, the structural isomer of 13.
Spinmarkierte Oligopeptide als substratanaloge Inhibitoren der Leucinaminopeptidase
Authors: Fittkau Siegfried , Damerau Werner 
Published: December 2004

Spin Labeled Oligopeptides as Substrate Analogous Inhibitors of Leucine AminopeptidaseThe synthesis of L‐Thr(But)‐(L‐Phe)n‐SL peptides C‐terminal labeled with the nitroxide spin label 2,2,5,5‐tetramethyl‐3‐amino‐pyrrolidin‐1‐oxyl, is described and e.s.r. parameters of the labeled compounds are presented. As shown by e.s.r. spectroscopy studies Thr(But)‐Phe‐SL is a competitive inhibitor of the leucine aminopeptidase and is bound by the enzyme with high affinity.
Acetals and ethers. VII. Hydrolysis‐Isomerization of 2‐Alkyl‐5‐Hydroxy‐1,3‐Dioxanes and 2‐alkyl‐4‐hydroxymethyl‐1,3‐dioxolanes in aqueous solution of hydrochloric acid
Authors: Sokołowski Adam , Burczyk Bogdann 
Published: December 2004

Acetale und Ether. VII. Hydrolyse‐Isomerisierung der 2‐Alkyl‐5‐hydroxy‐1,3‐dioxane und 2‐Alkyl‐4‐hydroxymethyl‐1,3‐dioxolane in wäßriger HCl‐LösungDie Geschwindigkeitskonstanten der Umsetzung von reinen cis‐ und trans‐2‐n‐Propyl‐ und 2‐n‐Amyl‐5‐Hydroxy‐1,3‐dioxanen (1a, 2a, 1b, 2b) bzw. der cis‐ und trans‐2‐n‐Propyl‐ und 2‐n‐Amyl‐4‐Hydroxymethyl‐1,3‐dioxalanen (4a, 3a, 4b, 3b) wurden in wäßriger HCl‐Lösung ermittelt. Weiterhin wurde nachgewiesen, daß in den Umsetzungsprodukten eines jeden Isomeren neben den Hydrolyseprodukten stets die drei anderen Isomeren vorhanden sind. Für einen bestimmten Hydrolysegrad des einzelnen Isomeren konnte das Verhältnis der sich im Reaktions‐produkt vorhandenen Isomeren bestimmt werden.
Synthese eines im B‐Kettenbereich um 5 Aminosäuren verkürzten, in den Positionen Phe B24 und Phe B25 durch Tyrosin und Alanin substituierten Hybridinsulins
Authors: Naumann Wolfgang , Stange Hans , Losse Günter , Bilk Lothar 
Published: December 2004

Synthesis of a Hybrid Insulin, Shortened in the B Chain Branch by 5 Amino Acids and Substituted in the Position Phe B24 and Phe B25 by Tyrosine and AlanineThe analogue of insulin B chain was synthesized in the protected form Z‐Phe‐Val‐Asn‐Gln‐His(Trt)‐Leu‐Cys(SEt)‐Gly‐Ser(Bzl)‐His(Trt)‐Leu‐Val‐Glu(OBzl)‐Ala‐Leu‐Tyr(Bzl)‐Leu‐Val‐Cys(SEt)‐Gly‐Glu(OBzl)‐Arg(HCl)‐Gly‐Tyr(Bzl)‐Ala‐OBzlNomenklatur und Abkürzungen nach den Regeln der IUPAC‐IUP‐Commission on Biochemical Nomenclature: Hoppe Seyler's Z. Physiol. Chem. 348, 256 (1967); J. Biol. Chem. 247, 977 (1972), weitere Abkürzungen: DCC =Dicyclohexylcarbodiimid, HOBt =1‐Hydroxybenzotriazol. DMF =Dimethylformamid, DMSO =Dimethylsulfoxid, B(SSO3−)2 =Insulin‐B‐Ketten‐S‐sulfonat

=Z‐1–25(Tyr24, Ala25)‐OBzl, converted into the S‐sulphonate form by deprotection and oxidative sulphitolysis, and combined with native A chain S‐sulphonate to the hybrid insulin A/B 1‐25(Tyr24, Ala25). The biological results indicate, that substitution of the amino acid Phe B24 is well tolerated, if the aromatic character of the side chain is remained.
Transannulare Reaktionen von Cycloalkenen, Cycloalkadienen und Cycloalkatrienen. VIII. Zur elektrophilen Addition von Pseudohalogenen an Cycloocta‐1(Z),5(Z)‐dien
Authors: Haufe Günter , Mühlstädt Manfred 
Published: December 2004

Transannular Reactions of Cycloalkenes, Cycloalkadienes and Cycloalkatrienes. VIII. The Electrophilic Addition of Pseudohalogenes to Cycloocta‐1(Z), 5(Z)‐dieneThe reaction of cycloocta‐1(Z), 5(Z)‐diene 5 with chlorothiocyanate is described. The main process is the normal anti‐addition to produce trans‐5‐chloro‐6‐thiocyanato‐(Z)‐cyclooctene 6. In addition 2,6‐dichloro‐9‐thiabicyclo [3.3.1] nonane 7 and 2,6‐dithiocyanato‐9‐thiabicyclo[3.3.1] nonane 8 are obtained as products of a transannular reaction.
1, 2, 3‐Triazabutadiene. XIV. Untersuchungen zur sauren Spaltung Z‐E‐isomerer 1‐Aryl‐3‐[3‐methylbenzthiazolinyliden‐(2)]‐ und 1‐Aryl‐3‐[1,3‐dimethylbenzimidazolinyliden‐(2)]‐triazene
Authors: Fanghänel E. , Hohlfeld J. 
Published: December 2004

1,2,3‐Triazabutadienes. XIV. Investigations into the Acidic Cleavage of the Z‐E‐Isomeric 1‐Aryl‐3‐[3‐methylbenzthiazolinyliden‐(2)]‐ and 1‐Aryl‐3‐[1,3‐dimethylbenzimidazolinyliden‐(2)]‐triazenesThe rate of the acid cleavage of the Z‐E‐isomeric 1‐aryl‐3‐[3‐methylbenzthiazolinyliden‐(2)]‐ and 1‐aryl‐3‐[1,3‐dimethyl‐benzimidazolinyliden‐(2)]‐triazenes 1–5 is investigated in dependence on the substituents in the aryl and benzo residue. The Z‐isomeric triazabutadienes are cleft 103 to 105 times faster than the E‐isomers. The ρ‐values are significantly smaller than the ρ‐values of the cleavage of other triazen derivatives. This is explained by an opposite influence of substituents regarding the cleavage of the N2‐N3‐bond and the equilibrium of protonation of the triazabutadienes. Triazabutadienes with a pronounced polymethine like structure decompose more rapidly than is conformable to their σ‐values. For the E‐isomers a V‐shape of the Hammett‐correlation is found. The considerable differences in the rate of heterolysis of the Z‐E‐isomers can be used for a negatively working diazo material which is sensitive to visible light.
Über die lipophile Natur von Oxyalkylgruppen in Alkylethersulfaten
Authors: Sowada Rudolf 
Published: December 2004

On the Lipophilic Nature of Oxyalkyl Groups in Alkyl Ether SulphatesEffective carbon numbers and methylene group equivalent values for tetradecane sulphonates containing oxyalkyl groups as substituents as well as and for alkyl ether sulphates containing oxyalkyl groups in the chain have been calculated. These oxyethyl groups show lipophilic character, at least up to an oxethylation degree of 10. Via ME values effective carbon numbers, critical concentrations for micelle formation and HLB‐values for alkyl ether sulphates can be calculated. HLB group numbers depending on oxalkylation degree are tabulated; the known value of + 0,33 for OCH2CH2 is valid only for nonionic surfactants.
Synthese von β‐Nitroalkenyl‐benzylphosphorylderivaten
Authors: Czekanski T. , Witek St. , Costisella B. , Gross H. 
Published: December 2004

Synthesis of β‐Nitroalkenyl‐benzylphosphorylderivativesStarting from methoxy‐chlormethylbenzaldehydes 2 the benzylphosphonates and ‐phosphinoxides 3 A, B had been synthesized, which could be transformed via the Schiff‐bases 4 A, B to phosphorylated nitrostyrenes 5 A, B and nitropropenylbenzenederivatives 6 A, B. The phosphonoacids 3 Ad, 3 Bd and 6 Ba could be prepared from the corresponding esters by direct acidic hydrolysis or by dealkylation with trimethylsilylbromide and hydrolysis of the trimethylsilylesters respectively.
Zur Kinetik radikalischer Substitutionsreaktionen beim thermischen und initiierten thermischen Zerfall von 4‐Methyl‐pentan‐2,3‐dion
Authors: Knoll H. , Barry I. , Scherzer K. 
Published: December 2004

On the Kinetics of Radical Displacement Reactions in the Thermal and Initiated Thermal Decomposition of 4‐Methyl‐pentane‐2,3‐dioneRelative rate constants of H‐abstraction and free radical displacement reactions in the thermal and initiated thermal decomposition of 4‐methyl‐pentane‐2,3‐dione have been determined between 523 and 683 K. The data are compared with previous results on other α‐diketones.
Elektronenstoßinduzierte Fragmentierung von para‐substituierten Styryl‐diphenylphosphinoxiden
Authors: Berndt K.‐G. , Gloyna D. , Henning H.‐G. 
Published: December 2004

Electron Impact Fragmentation of para‐Substituted Styryl‐diphenylphosphine OxidesPara‐substituted styryl‐diphenylphosphine oxides 1 exhibit a phosphine oxide‐like fragmentation. There are two competing ways, A and B, for electron impact fragmentation with the para‐substituent of the styrene part determining the A or B way, respectively. A styrene‐like fragmentation is to be excluded in respect to the observed mass spectra.
Reaktionen von zwitterionischen s‐Triazolo[4,3‐b]pyridazinen mit elektrophilen Reagentien
Authors: Timpe H.‐J. , Missal S. , Manzoor R. , Affi E. 
Published: December 2004

Reactions of Mesoionic s‐Triazolo[4,3‐b] pyridazines with Electrophilic ReagentsThe redox‐properties of zwitterionic s‐triazolo [4, 3‐b]pyridazines 1–3 depend on the heteroatom: products with S‐atoms can easily be oxidated. O‐Zwitterions 1 and 2 react with diazoniumsalts under azocoupling, while S‐zwitterions 3 lead to a dediazonation. The O‐zwitterions 1 and 2 can also be bromated, nitrated and hydroxylated electrophilicably. A reaction with dithioliumsalts is not possible. S‐Zwitterions 3 react in a more complicated way in the electrophilic reactions mentioned.
UV‐Vis‐spektroskopische Eigenschaften 3,5‐disubstituierter 1,3,4‐Oxadiazolin‐2‐imine. I. Einfluß der Substituenten und des Lösungsmittels auf die Absorption
Authors: Bendig Jürgen , Kreysig Dieter , Sauer Erika , Just Manfred 
Published: December 2004

The U.V.‐vis‐spectroscopic Properties of 3,5‐disubstituted 1,3,4‐Oxadiazoline‐2‐imines. I. The Influence of the Substituents and the Solvent on the AbsorptionThe u.v.‐vis data of 38 derivatives of 3,5‐disubstituted 1,3,4‐oxadiazoline‐2‐imines, measured in 12 different solvents, are discussed. The long wave absorption bands have charge‐transfer character, the observed solvatochromic shifts correlate with the solvent parameter ET. The assumed intramolecular charge‐transfer upon excitation is polarized in the direction R1N3C5R2. Derivatives which are donor‐substituted in the 3‐position of the oxadiazolinimine cycle (R1) and acceptor‐substituted in the 5‐position (R2) show a typical push‐pull effect. In this case bathochromic and hyperchromic effects on the long‐wave absorption bands result. On the other hand, R1is a donor and R2is an acceptor substituent the excitation energy is increasing.