bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxidative Kupplung CH‐acider Verbindungen mit p‐Phenylendiaminen. V. Massenspektrometrische Fragmentierung von 4‐substituierten 3‐Methyl‐1‐phenyl‐pyrazolin‐5‐onen
Authors: Wilde H. , Herzschuh R. , Lepom P. , Mann G.
Published: December 2004

Oxidative Coupling of CH‐acid Compounds with p‐Phenylenediamines. V. Mass Spectrometric Fragmentation of 4‐Substituted 3‐Methyl‐1‐phenyl‐pyrazolin‐5‐ones

The mass spectra of 3‐methyl‐1‐phenyl‐pyrazolin‐5‐one 1 and 4‐substituted derivatives 2–18 have been studied and the fragmentation mechanisms are discussed. The major cleavages take place in three ways, whose significance is related to the properties of the substituents. The mass spectra permit the determination of the structure, purity and stability of the substituted colour couplers.
Zur übergangsmetallkatalysierten nucleophilen Epoxidringöffnungsreaktion
Authors: Lauterbach Frau. G. , Posselt G. , Schäfer R. , Schnurpfeil D.
Published: December 2004

The Transition Metal Catalyzed Nucleophilic Epoxide Ring Opening Reaction

The catalytic influence of MoO2(acac)2

Acac‐Acetylacetonat

, Mo(CO)6, MoCl5, WCl6and TaCl5on the reaction of 1,2‐epoxy‐octane with ethanol at 100°C in dioxan or chlorobenzene as solvents is proved. Water and hydroperoxides react with a higher rate than alcohols. When changing from primary to secondary and tertiary alcohols a decrease of the reaction rate is observed. 2,3‐ and 3,4‐Epoxyheptane and cis‐ and trans‐4,5‐epoxy‐octane react more slowly than the corresponding 1,2‐epoxides. Epichlorhydrin and methylglycidether react with a lower, cyclohexene oxide, styrene oxide and norbornene oxide react with a higher rate than 1,2‐epoxyoctane. The reactivities of the two dicyclopentadiene monoepoxides correspond with the reactivities of the norbornene and cyclopentene oxides. In the molybdenum catalyzed epoxide ring opening reaction an isomer distribution appears in favour of the 1‐hydroxy‐2‐ethoxy‐alkane2. A mechanism in the coordination sphere of the transition metal complex is proposed.
Oxidative Kupplung CH‐acider Verbindungen mit p‐Phenylendiaminen. VI. 13C‐NMR‐Untersuchung der Tautomerie und des Substituenteneffektes 4‐substituierter Pyrazolin‐5‐one
Authors: Zeigan D. , Kleinpeter E. , Wilde H. , Mann G.
Published: December 2004

Oxidative Coupling of CH‐acid Compounds with p‐Phenylendiamines. VI. 13C‐N.M.R. Study of Pyrazolin‐5‐on Tautomerism and the Effect of 4‐Substituents

The 13C‐n.m.r. spectra of a series of 4‐substituted 3‐methyl‐1‐phenyl‐pyrazolin‐5‐ones 1–26 have been recorded and assigned. Examination of the chemical shifts of the heterocyclic ring carbons C‐3, C‐4, C‐5 and the 1‐phenyl carbons Cipso and Cortho permits to determine the preferred tautomeric forms of the compounds. In polar solvents like DMSO the OH‐form is dominant, sometimes besides a small component of the CH‐form. In nonpolar solvents like CDCl3 the CH‐form is preferred at room temperature besides a small component of the NH‐form. Cooling or addition of CH3OH to the solution shifts the tautomeric equilibrium to a higher amount of the NH‐form. The influence of 4‐substituents on the C‐3, C‐4 and C‐5 chemical shifts have been compared with the effect of these substituents on the Cipso and Cortho carbons in benzene. A linear dependence between C‐4 and Cipso shows, that the effect of substituents in pyrazolin‐5‐ones and benzene is controlled by their electronegativity. The substituent effects are influenced remarkably by intermolecular hydrogen bondings to polar solvents and by intramolecular hydrogen bondings, if possible.
Synthese und Löseverhalten smektischer 2,5‐Diphenylpyrimidine
Authors: Kraus G. , Zaschke H.
Published: December 2004

Synthesis and Retention Behaviour of Smectic 2,5‐Diphenyl‐pyrimidines

The synthesis of 2‐[4‐n‐alkylphenyl]‐5‐[4‐n‐alkoxy‐phenyl]‐pyrimidines 3, as well as the gas chromatographic investigations concerning the retention behaviour of their smectic A, C, F and G modifications for the substituted benzenes are described. Starting from the calculated enthalpies of solution and activity coefficients the intermolecular interactions in the range of terminal groups are discussed. The polarity of the stationary phases is proved by their chemical structure and only by a small part corresponding structure of the mesophases.
Oxydation von α‐Methylstyren in Gegenwart von Übergangsmetallverbindungen
Authors: Ivanov S. K. , Kateva J. , Dimitrov V. S. , Dahlmann J. , Höft E.
Published: December 2004

Oxidation of α‐Methylstyrene in the Presence of Transition Metal Compounds

The kinetics of oxygen absorption by α‐methylstyrene has been investigated under normal pressure at 60°C in the presence of Mo‐, Mn‐, Co‐, Ir‐, Rh and Pt‐compounds. Under these conditions only compounds of Co and Mo accelerated the reaction considerably. From the results, which were obtained by addition of AIBN, CHP or PPMS and ionol respectively, it can be concluded that the main course of the oxidation is a radical chain mechanism. The effect of the metal complex does not result from an interaction with the polyperoxide. Furthermore there were indications that in the initial phase of the reaction a direct activation and transfer of oxygen might also take place.
1,2,3‐Triazabutadiene. XIII. UV‐vis‐spektroskopische Untersuchungen zur Protonierung 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. XIII. U.V.‐vis‐Spectroscopic Investigations of the Protonation of Z‐E‐Isomeric 1‐Aryl‐3‐[3‐methylbenzthiazolinyliden‐(2)]‐ and 1‐Aryl‐3‐[1,3‐dimethylbenzimidazolinyliden‐(2)]‐triazenes

The u.v.‐vis absorption spectra of Z‐E‐isomeric 1‐aryl‐3‐[3‐methylbenzthiazolinyliden‐(2)]‐ and 1‐aryl‐3‐[1,3‐dimethyl‐benzimidazolinyliden‐(2)]‐triazenes 1–3 resp. 4 show a pronounced halochromic effect in the presence of acids. The reason is the protonation of the N1‐atom of the triazabutadiene chain whereby the energetically favourable structure of a diazatrimethine is formed. The magnitude of the halochromic effect depends on the substituents in the aryl and benzo residue and on the Z‐E‐structure of the compounds.
Photochemie substituierter Cycloheptatriene. XI [4]. Cyclisierung und Cycloreversion
Authors: Abraham W. , Paulick W. , Kreysig D.
Published: December 2004

Photochemistry of Substituted Cycloheptatrienes. XI. Cyclization and Cycloreversion

The photo‐valence‐isomerization of 1‐(p‐dimethylaminophenyl)‐4‐aryl‐cycloheptatrienes has been studied. The photoreactive state is assumed by a long wave emission state.

The dependence of reaction quantum yields on solvents and substituents points out that the reactive state is not very polar contrary to the assumption in the literature. Reactivity indices from front orbitals cannot describe the ring closure.

The parameters for thermically induced cycloreversion are discussed.
Cyclisierungsreaktionen β, γ‐ungesättigter Kohlensäurederivate. IV [1]. Synthese von N‐substituierten Thiazolidin‐2‐onen und 2‐Alkoxy‐2‐thiazolinen aus β,γ‐ungesättigten Thiocarbamidsäureestern
Authors: Mühlstädt M. , Widera R.
Published: December 2004

Cyclization Reactions of β,γ‐Unsaturated Derivatives of Carbonic Acid. IV. Synthesis of N‐Substituted Thiazolidine‐2‐ones and 2‐Alkoxy‐2‐thiazolines from β,γ‐Unsaturated Thiocarbamic Acid Esters

The reaction between N‐substituted β,γ‐unsaturated thiourethans and dry hydrogen chloride or bromine occurs in methylene chloride at room temperature. The thiourethans 1 a–4 a react with hydrogen chloride to give mixtures of corresponding 2‐alkoxy‐2‐thiazolines 6–9 and the thiazolidine‐2‐one 11 a. A useful synthetic route to N‐substituted thiazolidine‐2‐ones 11 is demonstrated by the reaction of N,N‐disubstituted β,γ‐unsaturated thiourethans with hydrogen chloride and bromine. The i.r. and H‐n.m.r.‐data of the compounds are described.
Desaktivierungsverhalten von Arenen und Heteroarenen. XXXI [11]. Ein Modell für die reversible Photodimerisierung von Anthracen und 9‐Methylanthracen
Authors: Bendig J. , Kreysig D.
Published: December 2004

Deactivation Behaviour of Arenes and Heteroarenes. XXXI. A Model of the Reversible Photodimerization of Anthracene and 9‐Methylanthracene

Starting from the Woodward‐Hoffmann state diagram of the reversible photodimerization of anthracene and 9‐methyl‐anthracene the potential correlation diagram is shown due to an excimer formation. This qualitative diagram is fixed by ten values of the state potential, which are determined directly or indirectly, respectively, by variation of the influence of environment. The mechanism and the kinetics of the photoreaction are discussed on the basis of the given potential correlation diagram and for the reversible photodimerization a common pericyclic transition state is assumed. The photochemical dimerization is a pure diabatic reaction. The photochemical decomposition of the dimer occurs mainly diabatic, and the quantum yield of the adiabatic excimer formation is only about the twentieth part of those of the diabatic reaction.
Photoinduzierte Valenzisomerisierungen von zwitterionischen s‐Triazolo[4,3‐b]pyridazinen
Authors: Timpe H.‐J. , Burggraf R. , Lammel U.
Published: December 2004

Photochemically Induced Valence Bond Tautomerism of Mesoionic s‐Triazolo[4,3‐b]pyridazines

The mesoionic s‐triazolo[4,3‐b]pyridazines 1–8 possess intensive charge‐transfer transitions, whose positions been influenced by the solvents. Some mesoionics fluoresce weakly. The irradiation gives valence isomers with a diaziridin ring. These products react under additional light irradiation to open‐chain ketenes, which incorporate methanol. The quantum yields of the valence bond tautomerism are between 0.08 to 0.45. They depend on the irradiation wavelength, the solvents and the substituents in the pyridazine‐part of the molecule. Because the oxygen‐insensibility and the sensibilisation with benzene and fluorene been supposed that these reaction take place in the S1‐state. The photoreaction of the valence isomer 9 of the mesoion 1 have a quantum yield of 0.13.
Pikosekunden‐Absorptionsspektroskopie an Pseudoazulenen
Authors: Graness A. , Kleinschmidt J. , Triebel W. , Olszowski A. , Timpe H.‐J.
Published: December 2004

Picosecond Absorption Spectroscopy of Pseudoazulenes

2‐Phenylcyclopenta[b] [1] benzopyran 1 and 6‐phenylindeno[2,1‐b][1]benzopyran 2 are excited by second harmonic or two photon absorption of the fundamental wave of a mode‐locked ruby laser and the time dependence of the spectra of the second excited singlet levels are probed. The lifetime of these states are found to be (130 ± 10) ps for 2 and ⩽20 ps for 1.
Oxidative Kupplung CH‐acider Verbindungen mit p‐Phenylendiaminen. VIII [1]. Synthese von 5H‐Benzo[a]phenothiazin‐5‐onen aus Naphth[2,1‐d]1,3‐oxathiol‐2‐onen
Authors: Mann G. , Wilde H. , Hauptmann S. , Lehmann J. , Naumann M. , Lepom P.
Published: December 2004

Oxidative Coupling of CH‐acid Compounds with p‐Phenylenediamines. VIII. Synthesis of 5H‐Benzo[a]phenothiazin‐5‐ones from Naphth[2,1‐d]1,3‐oxathiol‐2‐ones

Reaction of 5‐hydroxynaphth[2,1‐d]1,3‐oxathiol‐2‐ones with N,N‐diethyl‐quinone‐1,4‐diimine leads to 5H‐benzo[a]phenothiazin‐5‐ones 1–21. The same dyes are available by use of p‐substituted nitrosobenzenes in acetic acid, or in methanol in the presence of oxygen acceptors. The mechanisms of dye formation are discussed.
Steroide. LXIX [1]. Ringschlußreaktionen vicinaler Halogen‐urethane der Steroidreihe
Authors: Ponsold K. , Grosse P.
Published: December 2004

Steroids. LXIX. Cyclisation Reactions of Vicinal Substituted Halogen Carbamoyloxy Steroids

Vicinal halogen urethanes of the cholestane, androstane and estratriene series react by heating under solvolytic conditions to cyclic carbonates of the corresponding cis‐diols. By heating under basic conditions the same compounds react preferably to 2‐oxazolidinones and if the basic conditions are strong enough by hydrolysis of the oxazolidinones to cis‐amine alcohols too. Connections between the nature of the substituent at the urethane group or the steric arrangement of the vicinal groups on one hand and the reactivity to ring closure on the other hand are presented.
Synthesis of 6‐Hydroxy[1,3,4]oxadiazolo[2,3‐b]benzimidazoles
Authors: Soni R. P.
Published: December 2004

Zur Synthese von 6‐Hydroxy[1,3,4]oxadiazolo[2,3‐b]benzimidazolen
Über die Ringtransformation am 5‐Acetonyl‐2‐amino‐1,3,4‐oxadiazol
Authors: Rabe Harald , Westphal GÜNter
Published: December 2004

About Ringtransformation of 5‐Acetonyl‐2‐amino‐1,3,4‐oxadiazoles

Treatment of 1 with hydrazine derivatives gives first of all the 5‐acetonyl‐2‐amino‐1,3,4‐oxadiazole‐hydrazones 2 which can be isolated partially. In the second reaction step ringtransformation to the pyrazoles 3 takes place.

Hydroxylamine reacts in the same manner to the 3‐methyl‐5‐semicarbazido‐isoxazol 4.

The pyrazoles 3b and 3h can be dehydrogenated to the carboamoylazo‐pyrazoles 5a and 5b.
Photooxidation von Leukofarbstoffen. III. Sensibilisierte Photooxidation von Leukofluoreszein
Authors: Langbein H. , Paetzold R.
Published: December 2004

Photooxidation of Leuco Dyes. III. Sensitized Photooxidation of Leuco Fluorescein

Quantum yields of the sensitized photooxidation of leuco fluorescein are reported. Fluorescein and benzophenone were found to be efficient sensitizers of photooxidation of leuco fluorescein. There is a characteristic dependence of quantum yields on concentration of leuco fluorescein and oxygen in the solution. The results are discussed on the basis of reaction scheme proposed for the sensitized formation of fluorescein.
1H‐NMR‐Spektroskopische Isomerenzuordnung bei Cyclisierungs‐Reaktionen an Benzo‐kondensierten N‐Heterocyclen
Authors: Graubaum H. , Martin D.
Published: December 2004

1H‐NMR Spectroscopic Assignments of Isomeres to Cyclization Reactions of Benzo‐condensed N‐Heterocycles

Cyclic N‐acyl benzazoles show downfield shifts of the aromatic Ha proton at the 1H‐n.m.r. spectrum from 0.5 to 1.95 ppm which allows an assignment of possible isomeres and in some cases statements about the tautomerism. The ΔδHa values of 40 different azolo‐, azino‐, and azepino condensed benzimidazoles are given.
Phosphororganische Antioxidantien. I. Kinetik und Mechanismus der Zersetzung von Alkyl‐hydroperoxiden durch o‐Phenylen‐phosphite und ‐phosphate
Authors: Schwetlick K. , Rüger C. , Noack R.
Published: December 2004

Organophosphorus Antioxidants. I. Kinetics and Mechanism of the Decomposition of Alkylhydroperoxides by o‐Phenylene Phosphites and Phosphates

The reaction mechanism of 2‐(2, 6‐di‐tert‐butyl‐4‐methyl‐phenoxyl)‐1,3,2‐benzodioxaphosphole (1) with cumyl and t‐butyl hydroperoxide has been studied kinetically by means of 31P‐n.m.r. spectroscopy and high pressure liquid chromatography. 1 reacts with cumyl hydroperoxide to give the corresponding 2‐oxide (2) which with more hydroperoxide and/or water forms the open chained phosphate ester 5. This acidic phosphate decomposes hydroperoxide catalytically. The kinetic parameters of the separate reaction steps are given. The ionic mechanism of hydroperoxide decomposition is accompanied by a homolytic one in a minor proportion.
Zur Synthese und Abwandlung N‐substituierter 2(1 H)‐Pyrimidin‐thione ‐ Ein einfacher Zugang zu Pyrimidino[2,3‐b]1,3,4‐thiadiazoliumsalzen
Authors: Liebscher Jürgen , Hartmann Horst
Published: December 2004

Synthesis and Transformation of N‐substituted 2(1 H)‐Pyrimidine‐thiones – A Simple Route to Pyrimidino [2,3‐b]1,3,4‐thiadiazolium Salts

N‐substituted 2(1 H)‐pyrimidine‐thiones 4–6 can be prepared by reaction of primary amines or unsubstituted or substituted hydrazines with 3‐isothiocyanato‐propene‐(2)‐iminium salts 2, which are easily aviable from 3‐chloro‐propene‐(2)‐iminium salts 1. The 2(1 H)‐pyrimidine‐thiones are transformed into 2‐alkylmercapto‐pyrimidinium salts 7 and pyrimidino[2,3‐b]1,3,4‐thiadiazolium salts 9, respectively.
Photoinduzierte Zersetzung von Arendiazoniumsalzen durch Pyrazolon‐ und Naphtholfarbstoffe
Authors: Timpe H.‐J. , Schubert E. , Worschech S.
Published: December 2004

Photoinduced Decomposition of Arene Diazonium Salts by Pyrazolone and Naphthole Dyes

The pyrazolone dyes 1–4 in their photoexcited singlet states bleached out by arene diazonium salts which dediazoniate during the reaction. Both compounds react in equal proportion. The quantum yields increase with the increasing of the concentration and electron acceptor properties of the diazonium salts and increasing of the electron donor properties of the dyes.

The quantum yields of dye bleaching decrease on addition of DABCO or allylic thiourea, whereas the dediazoniation is not influenced. A kinetic model based on a primary electron transfer from the excited dye to arene diazonium salt is presented and used to determine rate constants for individual partial reactions.
Ionenpaargleichgewichte komplexer Carbeniumionensalze als Modelle für die aktive Spezies bei der kationischen Polymerisation
Authors: Heublein Günther , Grimmer Cornelia
Published: December 2004

Ion‐pair Equilibria of Complex Carbenium Ion Salts as Models of the Active Species in Cationic Polymerization

The dissociation equilibria of complex carbenium ion salts [(C6H5)3C⊕, C7H7⊕MtX⊖n+1] have been determined in chloroform, dichloroethane and nitromethane from conductance measurements. The dissociation constants remain almost unchanged for different anions, are however influenced markedly by the polarity of the solvent.

The fractions of free and paired ions in these solvents have been calculated.

Furthermore the enthalpies and entropies of dissociation have been evaluated.
Photochemische Primärprozesse von Xanthenfarbstoffen. I. Blitzlichtspektroskopische Untersuchung der Primärprozesse von Selenopyronin
Authors: Ortmann W. , Kassem A. , Hinzmann S. , Fanghänel E.
Published: December 2004

Photochemical Primary Processes of Xanthene Dyes. I. Investigations of the Primary Processes of Selenopyronine by Flash Excitation

The triplet‐state of selenopyronine absorbs light in the whole investigated spectral range (λmax = 400 nm, 480 nm, 690 nm). As results of the bimolecular triplet decay a half‐reduced (λmax = 430 nm) and a half‐oxidized (λmax = 475 nm) form of the dye are observed. p‐Benzoquinone quenches the triplet‐state (k7 = 1,5 · 109 l/mol s) and the results are the half‐oxidized form and the p‐benzosemiquinone ion. For these two products different decay processes exist. The reducing agents DABCO, EDTA and Hydroquinone also quench the triplet state (k10 = 1,2 · 106 l/mol s, k11 = 1,0 · 106 l/mol s, k12 = 1,0 · 109 l/mol s) and as result the half‐reduced form is observed. Measurements with thiopyronine give analogous results, which are in good agreement with investigations published in the literature.
Thermal decomposition of quinone: Synthesis of Anthrimidazodiones
Authors: Jain M. L. , Soni R. P.
Published: December 2004

Thermischer Zerfall von Chinonen Synthese von Anthrimidazodionen

Der thermische Zerfall von Endo‐9,10‐o‐phenylen‐2‐chlor‐3‐azido‐9,10‐dihydro‐1,4‐anthrachinon (2) in einem Überschuß einer heterocyclischen tertiären Base, z. B. Pyridin, Chinolin, Isochinolin, α‐, β‐, γ‐Picolin, Lutidin und Collidin ergibt die Anthrimidazodione (5, 6, 7). Diese werden ebenfalls durch einen Alternativweg synthetisiert: die Kondensation von Endo‐9,10‐o‐phenylen‐2,3‐dichlor‐9,10‐dihydro‐1,4‐anthrachinonen (1) mit 2‐Aminopyridin. Chinolin bzw. Isochinolin in Ethanol ergibt die Verbindungen 9a–c. Diese werden anschließend in Eisessig zu den Verbindungen 5, 6, 7 cyclisiert, deren Struktur durch Elementaranalyse und spektroskopische Daten gesichert wird.
Studies on the Synthesis of 8,15‐Dimethyl Prostanoids. A Facile Allylic Rearrangement of the 15‐Alkoxy‐15‐Methyl Prosta‐11,13‐Diene System
Authors: Schwarz S. , Weber G. , Schick H.
Published: December 2004

Untersuchungen zur Synthese von 8,15‐Dimethylprostanoiden. Allylumlagerung des 15‐Alkoxy‐15‐methyl‐prosta‐11,13‐diens

Ausgehend von durch mikrobielle Transformation zugänglichem (2S, 3S)‐3‐Hydroxy‐2‐methyl‐2‐(prop‐2‐inyl)‐cyclopentanon (2) wurde der 1,9,15‐Tris‐(α‐ethoxy)ethylether des (15RS)‐1,9α,15‐Trihydroxy‐8,15‐dimethyl‐prosta‐11,13(E)‐dien‐5‐ins (22) in 9 Stufen dargestellt. Hydrolyse dieses Ethers führte zur Allylumlagerung unter Beteiligung des jeweiligen Lösungsmittels: in Ethanol entstand 11‐Ethoxy‐1,9α‐dihydroxy‐8,15‐dimethylprosta‐12,14(E)‐dien‐5‐in (23), während sich in Gegenwart von Essigsäure die entsprechende 11‐Acetoxyverbindung (24) bildete.
1H‐NMR‐spektroskopische Untersuchungen zur Stereochemie von Butadienderivaten
Authors: Castanedo N. , Peseke K. , Kelling H. , Michalik M.
Published: December 2004

1H‐N.M.R. Spectroscopic Investigations on Stereochemistry of Substituted Butadienes

The butadienes 1–6, obtained by Knoevenagel condensation of furfuryliden, 5‐bromofurfuryliden, and benzylidenaceton with malononitril and ethyl cyanoacetat respectively, have been investigated 1H‐n.m.r. spectroscopically. Structure and configuration of the isomers could be determined with the help of deuteration experiments, anisotropy effects, and Eu(fod)3 shift reagents measurements.
NMR‐spektroskopische Untersuchungen zum Konformations‐verhalten von 2′‐ und 3′‐halogensubstituierten Pyrimidinnucleosiden
Authors: Joecks A. , Köppel H. , Schleinitz K. D. , Cech D.
Published: December 2004

N.M.R. Spectroscopical Investigations on the Conformational Behaviour of Some 2′ ‐ and 3′‐Halogen‐substituted Pyrimidine Nucleosides

A series of 2′‐ and 3′‐halogenated pyrimidine nucleosides has been synthesized and investigated by 1H, 13C and 19F n.m.r. spectroscopy. The 1H and 13C chemical shifts for the positions 2′ and 3′ depend linearly but oppositely on the substituent electronegativities XR.

The conformational equilibrium N ⇌ S of the nucleosides in solution is determined. An approximately linear correlation between the prefered gauche‐gauche interaction of the exocyclic CH2OH groups and the ribose N conformation has been found.
Tetrathiafulvalene. XX. Charge‐Transfer, Radikalkonzentration und elektrische Eigenschaften von TTF und TSF‐TCNQ‐Komplexen
Authors: Fanghänel E. , Schukat G. , Schützendübel J. , Humsch W.
Published: December 2004

Tetrathiafulvalenes XX. Charge‐Transfer, Radical Concentration and Electrical Properties of TTF‐ and TSF‐TCNQ‐Complexes

For TTF‐TCNQ‐complexes the spin density increases with a higher degree of CT, estimated from the value of C‐N‐vibration in TNCQ. The dihydronaphthocondensed cis‐ and trans‐TSF‐TCNQ‐complexes (11, 12) show the same high conductivity, whether the complex composition is 2:1 or 1:1.
Thermitase – eine thermostabile Serinprotease. III. Synthese von N‐Acyl‐peptidmethylketonen als reversible Enzyminhibitoren
Authors: Fittkau Siegfried , Jahreis Günther
Published: December 2004

Thermitase – A Thermostable Serine Protease. III. Synthesis of N‐Acylated Peptide Methyl Ketones as Inhibitors Reversibly Bound to the Enzyme

Methyl ketone derivatives of dipeptides to pentapeptides are used as suitable tools in the investigation of the non‐covalent binding for subsite mapping of the active site of the enzyme. The synthesis is mainly performed by fragment condensation of N‐acylated peptides or amino acids with methyl ketone derivatives of amino acids. These are prepared from the Z‐protected

Abkürzungen: Ac = Acetyl, Z = Benzyloxycarbonyl, Boc = t‐Butyloxycarbonyl, Suc = Succinyl, Glp = Pyroglutamyl, OBz = Benzylester, pNA = p‐Nitranilid, CH3 = Methylketon, CH2Cl = Chlormethylketon, MA = Mischanhydridmethode, TEA = Triethylamin, NEM = N‐Ethylmorpholin, CKEE = Chlorkohlensäureethylester, CKBE = Chlorkohlensäurebutylester, MeOH = Methanol, EtOH = Ethanol, AcOH = Essigsäure, Ac2O = Acetanhydrid, Etac = Ethylacetat, THF = Tetrahydrofuran, E = Ether, PE = Petrolether, DMF = Dimethylformamid, DMSO = Dimethylsulfoxid, DMAP = 4‐(Dimethylamino)‐pyridin

cloromethyl ketones by catalytic hydrogenation. For the coupling steps the Z‐protection is preferred. The peptide methyl ketones used in kinetic studies were N‐protected by the Z, acetyl, Boc or pyroglutamyl residue.
Protonierung und Solvatation schwacher organischer Basen. I. Zur Basizität von ω‐Chloracetophenonen
Authors: Freiberg W. , Scheer J. , Streich U. , Starick E. , Kröger C.‐F.
Published: December 2004

Protonation and Solvation of Weak Organic Bases. I. Basicity of ω‐Chloroacetophenones

The protonation equilibria of ω‐chloroacetophenone and some p‐substituted derivates have been studied in the acid system H2O/H2SO4/SO3 by u.v. and 1H‐n.m.r. spectroscopy. From the determined H0 values for half‐protonation pKBH+ values were calculated by means of the solvation parameters m of YATES and McCLELLAND. The (H0)1/2 and the pKBH+ values were successfully correlated with σp and σp+ substituent constants.
2, 2‐Disubstituierte Cyclopentan‐1, 3‐dione. IV. Synthese prochiraler Zwischenprodukte für 8‐Methyl‐prostaglandin C2 durch C‐Alkylierung von 2‐Methylcyclopentan‐1,3‐dion mit 1‐Brom‐alk‐2‐inen
Authors: Schick H. , Schwarz H. , Theil F. , Schwarz S.
Published: December 2004

2, 2‐Disubstituted Cyclopentane‐1, 3‐diones. IV. Synthesis of Prochiral Intermediates for the Synthesis of 8‐Methyl‐prostaglandin C2 by Alkylation of 2‐Methyl‐cyclopentane‐1, 3‐dione with 1‐Bromo‐alk‐2‐ynes.

2‐Methyl‐cyclopentane‐1, 3‐dione (1) is preferentially C‐alkylated by 1‐bromo‐alk‐2‐ynes in aqueous sodium hydroxide solution. By this method it is possible to prepare 2,2‐disubstituted‐1, 3‐diones (3–8), which can be converted into prochiral intermediates for 8‐methyl‐PGC2, containing the complete carboxylic side chain.
The Reaction of Malononitrile with Enamines of some cyclic β‐Keto acid anilides and amidines
Authors: Bogdanowicz‐Szwed Krystyna , Policht Andrzej
Published: December 2004

The reaction of enamines 1 derivatives of cyclohexanon‐ or cycloheptanon‐2‐carboxylic acid anilides with malononitrile gave in the first step 2‐phenylcarbamoyl‐cycloalkylideno‐malononitriles 3, which in turn were converted into 1‐oxo‐2‐phenyl‐3‐amino‐4‐cyano‐cycloalkenoisoquinolines 4. Enamines containing an adjacent diphenylamidino group 6 reacted with malononitrile giving 1‐phenylimino‐2‐phenyl‐3‐amino‐4‐cyano‐cycloalkenoisoquinolines 7. The alkaline hydrolysis of 7 yielded 1‐phenylamino‐3‐oxo‐4‐cyano‐cycloalkenoisoquinoline 8.
Desaktivierungsverhalten von Arenen und Heteroarenen. XLI [1b]. Struktur‐ und Umgebungseinflüsse auf die intramolekulare [π4s + π4s]‐photo‐cycloaddition von α,ω‐Bis‐(9‐acridiziniumyl)‐alkanen
Authors: Wagner J. , Bendig J. , Kreysig D.
Published: December 2004

Deactivation Behaviour of Arenes and Heteroarenes. XLI. Structural and Environmental Effects on the Intramolecular [π4s + π4s]‐ Photocycloaddition Reaction of α, ω‐Bis‐(9‐acridiziniumyl) ‐ alkanes.

Fluorescence characteristics, including quantum yields and decay times, and quantum efficiencies for the reversible intramolecular [π4s + π4s]‐ photocycloaddition reaction for a series of α, ω‐bis‐(9‐acridiziniumyl)‐alkanes have been measured in several solvents and they have been compared with those of the model compounds acridizinium‐ion. and 9‐methyl‐acridizinium‐ion. These parameters of the bichromophores depend on the number of CH2‐groups of chromophor linkage. The title compounds investigated were divided into groups of common behaviour, and differences are due to increasing bond angle strain and coulomb‐repulsion in the photocyclomer state.
Polarographic study of the Reduction of Cadmium(II) and Lead(II) in DL‐norleucine media
Authors: Saxena R. S. , Dhawan S. K.
Published: December 2004

In continuation of our earlier work on the electrochemical behaviour of amino acids and their metal complexes [1–3], the present investigation reports the polarographic behaviour of Cd(II) and Pb(II) in presence of DL‐norleucine, formation and composition of their complexes, determination of stability constants by DEFORD and HUME'S method [4] and MIHALLOV'S mathematical approach [5] at 20° and 30°C and also thermodynamic parameters accompanying complexation reactions at 20°C.
Reaktionen von Cyclanyl‐Radikalen in der Gasphase. II. Cyclohexyl‐Radikale aus Azomethan‐Cyclohexan‐Gemischen
Authors: Ondruschka B. , Zimmermann G. , Anders G.
Published: December 2004

Reactions of Cyclanyl Radicals in the Gas Phase. II. Cyclohexyl Radicals from Mixtures of Azomethane and Cyclohexane

Cyclohexane‐azomethane mixtures in argon as diluent were converted by temperatures between 400 and 480°C in a stirred flow system. All products were analytically determined in a comprehensive way. In this way not only isomeric C6H11‐radicals, which were already known from former investigations, but also hitherto unknown C6H11‐radicals, especially the 3‐methylcyclopentyl radical, could be detected as a recombination product with methyl radicals or as the corresponding olefinic compounds. From the results the stationary concentrations of important radical species were estimated and mechanistic consequences discussed.
Photooxidation von Leukofarbstoffen. VIII. Kurzzeitspektroskopische Untersuchungen zum Mechanismus der Photooxidation von Leukokristallviolett
Authors: Hinzmann G. , Grummt U.‐W. , Paetzold R.
Published: December 2004

Photooxidation of Leuco Dyes. VIII. Time Resolved Investigations of the Mechanism of the Photooxidation of Leucocrystal Violet

The photooxidation of leucocrystal violet has been reexamined by means of conventional and laser flash photolysis as well as spin trap experiments. Three radical transients have been observed and assigned to the cation radical (λmax ≈ 490, 530 nm), the neutral radical with oneNCH3CH2 moiety (λmax ≈ 480 nm) and the triphenyl methyl radical derivative (λmax ≈ 400 nm).
Palladium‐katalysierte Addition von Methanol an Isopren
Authors: Gaube W. , Stegemann H.
Published: December 2004

Palladium‐Catalyzed Addition of Methanol to Isoprene

The soluble systems containing palladium(II)‐compounds and tri‐n‐butylphosphine as a ligand catalyze the addition of methanol to isoprene to give methoxyisopentenes in goodyields. Activity and selectivity of the reaction are dependent on the ligand, the ratio ligand to palladium and in a surprising manner on the concentration of methanol.
Photokatalytische Systeme. LXIV. Theoretische Untersuchungen zum Ladungstransfer und zur Photoreaktivität von π‐Akzeptorligandkomplexen mit d6‐Übergangsmetallen
Authors: Benedix R. , Hennig H.
Published: December 2004

Photocatalytical Systems. LXIV. Theoretical Investigations of the Charge Transfer and of the Photochemical Reactivity of d6 Transition Metal Complexes with π Acceptor Ligands

Quantum chemical investigations concerning the charge transfer interactions between a d6 complex fragment and heterocyclic nitrogen ligands are reported. The influence of inductive, mesomeric and steric effects on the π acceptor ability of the isolated ligand and on the electronic structure of the pentacyano‐ferrate(II) mixed ligand compounds has been investigated and possibilities to sensitize spectrally the Fe(CN)5L3− system (L= pyridine‐type ligand) with regard to their photochemical reactivity are discussed.
Eine neue Methods zur Einführung von CF3‐ und C2F5‐Gruppen in Pyrimidinderivate und die Anti‐Herpes‐Aktivität der Verbindungen
Authors: Schwarz B. , Cech D. , Reefschläger J.
Published: December 2004

A New Method of the Introduction of CF3‐ and C2F5‐Groups into Pyrimidine Derivatives and their Antiherpes Activity

A new method of the perfluoroalkylation of uracil derivatives is described. The irradiation of aqueous solutions of uracil and uracilnucleosides with bis‐(perfluoroalkyl) mercury (CnF2n+1)2Hg n = 1, 2 under the exclusion of oxygen in the presence of catalytic amounts of azo‐bis‐isobutyronitril at 254 nm for several hours gave new 5‐perfluoroalkylated compounds. In this way we obtained 5‐trifluoromethyluracil (5a), 5‐pentafluoroethyluracil (5b), 5‐trifluoromethyl‐2′‐deoxyuridine (6a), 5‐pentafluoroethyl‐2′‐deoxyuridine (6b) and 1‐(ß‐D‐arabinofuranosyl)‐5‐trifluoromethyluracil (7a) in different yields. The perfluoroalkylated compounds were tested against HSV‐1 and HSV‐2 viruses on human lungefibroblasts. The compounds are markedly less potent than other known nonfluorinated compounds.
Photochemie von Aminoketonen. VII. Eine diastereoselektive Synthese von 3‐Hydroxy‐prolinen
Authors: Haber H. , Buchholz H. , Sukale R. , Henning H.‐G.
Published: December 2004

Photochemistry of Aminoketones. VIII. Diastereoselective Synthesis of 3‐Hydroxy‐prolines

Glycine esters react in two steps (aminoalkylation and N‐acylation) to N‐acyl‐N‐(β‐benzoylethyl)‐glycine ester 3. In less polar solvents these ketonic compounds are n,π*‐excited by 300 nm irradiation. In ether 3* yield mixtures of aminocyclopropanoles 4, hydroxyprolines 5 and products of additions and cleavages. In benzene and cyclohexane/benzene, respectively, the regioselective photocyclization to 5 is favoured. Furthermore this hydroxyproline synthesis has the advantages of high diastereoselectivity yielding the (2,3) E–5 and of high overall‐yields in connection with the one pot method. The influence of solvents and substituents on the regio‐ and diastereoselectivity are explained using a model with stabilization of special conformations of intermediates by dipol‐dipol interactions.
Untersuchungen zum UV/Vis‐Spektralverhalten von Azofarbstoffen. XII. Eine Analyse der Korrelationen zwischen Absorptionsmaxima und den Hammett‐σ‐Konstanten der Substituenten
Authors: Mustroph H.
Published: December 2004

Studies on UV/Vis Absorption Spectra of Azo Dyes. XII. An Analysis of the Correlations between Absorption Maxima and Hammett‐σ‐Constants for the Substituents

Previously claimed relationships between wavelength shifts and Hammett‐σ‐constants for the substituents are mostly unfounded. In certain cases, good linear correlations are found, but in other cases the plots deviate appreciably from linearity.

We have examined such correlations on the basis of the classification scheme of organic dyes suggested by Fabian (charge transfer‐(CT)‐chromophores, locally excited‐(LE)‐chromophores) respectively Griffiths (donor‐acceptor chromogens, cyanine‐type chromogens).

It was shown that good linear correlations should be obtained by LE‐chromophores (cyanine‐type chromogens). In CT‐chromophores (donor‐acceptor chromogens) however, an electron withdrawing substituent in the acceptor fragment causes a bathochromic displacement of the absorption maxima, and in the donor fragment it has little influence. A reversed behaviour was assumed for electron releasing substituents. Thus in CT‐chromophores V‐type correlations should be obtained.

These rules are equally applieable to interpret the linear relationships between σ‐constants and the difference between the absorption maxima of two different, equilibrating species.
Folgeprodukte aus Sulfonamiden. VI. Darstellung und Cyclisierung von N‐Allyl‐N′‐arylsulfonyl‐thioharnstoffen
Authors: Hans M. , Dehne H.
Published: December 2004

Consecutive Products of Sulphonamides. VI. Synthesis and Cyclization of N‐Allyl‐N′‐arylsulphonyl‐thioureas

N‐Allyl‐N′‐arylsulphonyl‐thioureas 3a–e are synthesized by addition reaction of substituted arensulphonamides 2a–e and allylisothiocyanate 1. The thioureas 3a–e react with hydrogen bromide in acetic acid or bromine in chloroform to 2‐(arylsulphonylimino)‐5‐methyl‐(or bromomethyl)thiazolidines 8a‐j. The mechanism of reaction and the structures are discussed by means of i.r., m.s. and 1H‐n.m.r. data.
Synthesis, Spectroscopy and Tautomeric Study of Thiazoles substituted in positions 2 and 4 by hydroxy, mercapto and amino groups
Authors: Valls N. , Segarra V. M. , Alcalde E. , Marin A. , Elguero J.
Published: December 2004

Thiazoles substituted in positions 2 and 4 by hydroxy, mercapto and amino groups were synthesized, as well as its carbamate derivates and formylhydrazones. The research of the reaction of the formylhydrazide with 4‐imino‐2‐thiazolidinone has not given the pyrazolo [3,4‐d]‐ thiazol‐2‐one, but the 4‐formylhydrazono‐2‐thiazolidine. The detailed tautomeric study of each of the heterocyclic compounds has been carried out by infrared spectroscopy, nuclear magnetic resonance of proton and of 13‐carbon, and of masses.
Molecular geometry and excited electronic states. XII. Equilibrium Geometries of 9‐Phenyl Anthracene in different electronic states and its electronic spectral behaviour
Authors: Gustav K.
Published: December 2004

Within the framework of a complete geometry‐optimization the molecular geometries of 9‐phenyl anthracene in the S0, S1and T1states have been determined by means of the Warshel‐Karplus method. In all cases twisted structures have been found. In addition to this, for the excited electronic states the presence of the anthracene ring acoplanarity has to be emphasized. Taking into account the theoretical molecular geometries the electronic transition energies and oscillator strengths have been calculated and used for the interpretation of the electronic spectral behaviour in absorption and fluorescence. The theory‐experiment comparison performed is satisfactory and confirms the calculated structures of 9‐phenyl anthracene indirectly.
Iodierung von N‐Aryl‐2,4‐dimethyl‐buta‐1,3‐dien‐1,4‐sultamen
Authors: Fanghänel E. , Mohammed H. , Richter A. M. , Radeglia R.
Published: December 2004

Iodation of N‐Aryl‐2,4‐dimethyl‐buta‐1,3‐dien‐1,4‐sultames

By the iodation of N‐aryl‐2,4‐dimethyl‐buta‐1,3‐dien‐1,4‐sultames 1 with I2/HgO in EtOH/AcOH the 1,2‐thiazine ring is substituted. The monosubstitution occurs on the 1‐position (1a, d) and the disubstitution on the 1,3‐position (3a). By iodine monochloride in CHCl3 the sultames 1a–d were substituted in the (C‐2)‐CH3 group (4a–d), in contrast also to the results of chlorination and bromination of 1. The structure of the products 2, 3, 4 was proved by 13C‐n.m.r. spectroscopic data.
Formylation products of thioamides. XIII. Reaction of N‐(3‐aminothioacryloyl)‐formamidines with amines – Synthesis of Pyrimidine Derivatives
Authors: Knoll Alexander , Liebscher Jürgen
Published: December 2004

N‐(3‐Aminothioacryloyl)‐formamidines 3 react with primary amines to give either 4(1H)‐pyrimidinthiones 6 or transaminated N‐(3‐aminothioacryloyl)‐formamidines 5. Alkylation of the latter compounds gives rise to cyclised 6(1H)‐pyrimidinimines 7. The 4(1H)‐pyrimidinthiones 6 can be S‐alkylated to 4‐alkylmercaptopyrimidinium salts 8. Subsequent substitution of the alkylmercapto group of the 8 results in the formation of 4‐aminopyrimidinium salts 9, which can also be obtained starting from the 3 by a reversed reaction sequence that is first by S‐alkylation to 3‐alkylmercapto‐2‐azapentamethinium salts 10 and subsequent reaction with primary amines.
Reversible Photoisomerisierungen an Sulfophthalein‐Indikatorfarbstoffen. IV. Stopped‐Flow‐Untersuchungen zum Mechanismus der baseninduzierten Sultonringöffnung
Authors: Grummt U.‐W.
Published: December 2004

Reversible Photoisomerizations of Sulfophthalein Indicator Dyes. IV. Stopped Flow Investigations on the Mechanism of the Base Induced Sulton Ring Opening

The colour formation of rapidly mixed solutions of bromo thymol blue and organic bases in toluene obeys a biexponential rate law. The most probable reaction sequence is: Sulton (colourless) + base ⇌ ring opened H‐bridged complex (λmax ≈ 420 nm) ⇌ H‐bridged ion pair (λmax ≈ 400 nm). Alternative reaction schemes of the same complexity could be ruled out though the underlying kinetic problem is underdetermined. As a generalizing conclusion it is stated that valuable mechanistic and kinetic information may be derived from underdetermined kinetic problems by calculating the ranges of physically meaningful solutions for the unknowns which are compatible with the particular kinetic schemes instead of the unavailable singular solutions.
Eine neue Synthese substituierter 4‐Amino‐1,3‐thiazole
Authors: Evers R.
Published: December 2004

A New Synthesis of Substituted 4‐Amino‐1, 3‐thiazoles

In the 5‐position substituted 4‐amino‐2‐alkylthio‐1, 3‐thiazoles are prepared in good yields from N‐nitro‐amidino‐dithiocarbamates1and α‐halogen‐carbonylcompounds or chloracetonitrile.1reacts with 1, 3‐dichlor‐acetone under formation of adequate bis(1, 3‐thiazolyl)ketones.

According to the same principle the reaction of the dipotassium salt of the N‐nitro‐amidino‐dithiocarbimidic acid7with two equivalents of the α‐halogen‐carbonylcompound yields 4‐amino‐5‐benzoyl‐2‐(benzoyl‐methylthio)‐1, 3‐thiazoles.
Potential anticancer agents. XXVI. Spin Labelled Nitrosoureas
Authors: Baracu Ileana , Dobre V. , Niculescu‐Duvaz I.
Published: December 2004

In order to obtain more information about the in vivo mechanism of action of nitrosoureas, the synthesis of spin labelled nitrosoureas derived from 1‐oxyl‐2.2.6.6‐tetramethyl‐4‐aminopiperidine was undertaken. The synthesis of four spin labelled ureas 4a–4d was reported as well as two spin labelled nitrosoureas:1‐methyl‐3‐(2′.2′.6′.6.′‐tetramethyl‐piperidin‐4′‐yl‐1′‐oxyl)‐1‐nitrosourea(9a) and 1‐(2′‐chloroethyl)‐3‐(2″,2″.6″.6″‐tetramethyl‐piperidin‐4″‐yl‐1″‐oxyl)‐nitrosourea(9b). Their e.s.r. spectra were recorded. None of these compounds proved to be active against L1210.
Tetrathiafulvalene. XXII [1] Redox‐ und spektroskopische Eigenschaften von Tetrathiafulvalenen (TTF) und Tetraselenafulvalenen (TSF) sowie deren Mono‐ und Dikationen
Authors: Schukat G. , Fanghänel E.
Published: December 2004

Tetrathiafulvalenes. XXII. Redox‐ and Spectroscopic Properties of Tetrathiafulvalenes (TTF) and Tetraselenafulvalenes (TSF) and their Mono‐ and Dications

The polarographic oxidation potential of TTF is decreased by alkyl‐ and increased by aryl‐substituents. The oxidation potentials of arylated TTF can be correlated with σ+‐constants (σ  0,1). TSF are weaker donors than the respective TTF. Alkyl substitution at TTF causes a bathocromic shift and aryl substitution a hypsochromic shift of the longest wavelength absorption band. In the mono‐ and dications of TTF a bathochromic shift of this absorption band is observed by alkyl‐ as well as aryl‐substituents which is especially pronounced, when the molecule is planar.
Synthesis and reactions of 2‐(p‐chloroanilino)‐5‐ (D‐galacto‐1,2,3,4,5‐pentahydroxypentyl)‐1,3,4‐thiadiazole
Authors: El Ashry El Sayed H. , Nassr Mahmoud A. M. , El Kilany Yeldez , Mousaad Ahmed
Published: December 2004

Oxidative cyclization of D‐galactose (p‐chlorophenyl)thiosemicarbazone gave 2‐(p‐chloroanilino)‐5‐(D‐galacto‐1,2,3,4,5‐pentahydroxypentyl)‐1,3,4‐thiadiazole (1), whose acetylation afforded 2‐[N‐acetyl‐N‐(p‐chlorophenyl)]‐amino‐5‐(D‐galacto‐1,2,3,4,5‐pentacetoxypentyl)‐ 1,3,4‐thiadiazole (3). Its periodate oxidation of the glycol groups gave 2‐(p‐chloroanilino)‐1,3,4‐thiadiazole‐5‐carboxaldehyde (4), which can be transformed into 1,2‐[2‐(p‐chloroanilino)‐1,3,4‐thiadiazol‐5‐yl]‐1‐hydroxy‐2‐oxoethane. A number of hydrazones of the formyl thiadiazole was prepared and its reduction with sodium borohydride gave 2‐(p‐chloroanilino)‐5‐hydroxymethyl‐1,3,4‐thiadiazole (6), whose acetylation gave a mono‐O‐acetyl derivative (7). Oxidation of the formyl thiadiazole gave 2‐(p‐chloroanilino)‐1,3,4‐thiadiazole (9). The spectral data of the compounds were discussed.
Studien über die Autoxidation von 1‐Phenylbuta‐1,3‐dien und 2‐Phenylbuta‐1,3‐dien
Authors: Blau K. , Voerckel V. , Willecke L.
Published: December 2004

Studies on the Autoxidation of 1‐Phenylbuta‐1,3‐diene and 2‐Phenylbuta‐1,3‐diene

Hydrogenation of the polymeric peroxides formed during the autoxidation of 1‐phenylbuta‐1,3‐diene (1) and 2‐phenylbuta‐1,3‐diene (10) at 50°C in an autoclave yielded 1‐phenylbutane‐3,4‐diol (5) and 2‐phenylbutane‐1,4‐diol (12), respectively.

The LiAlH4 reduction of 1‐phenylbuta‐1,3‐diene oxidate (50°C) yielded cinnamyl alcohols (4) as a major product.

The oxygen‐containing polymeric products formed along with Diels‐Alder dimers during the oxidation of the title substances at 140°C showed no degradation after subjecting to hydrogenation and are therefore considered as polyethers.
Fotochemische Primärprozesse von Xanthenfarbstoffen. V. Untersuchungen zum Mizelleinfluß auf die fotochemischen Primärprozesse von Erythrosin
Authors: Ortmann W. , Winnig B. , Fanghänel E.
Published: December 2004

Photochemical Primary Processes of Xanthene Dyes. V. Investigations of the Influence of Micelles on the Photochemical Primary Processes of Erythrosine

The triplet state of erythrosine decays in water solution mono‐ and bimolecularly (k1 = 0,85 · 104 s−1; kbi = 7,6 · 108 l/mol s). As results of the bimolecular triplet decay a half‐reduced and a half‐oxidized form of the dye are observed. The dye ions are localized in the Stern layer of cationic micelles. The triplet state of those dye ions, which are localized individually at micelles, decays only monomolecularly (k = 2,1 · 103 s−1). If two or more dye ions are localized at a micelle, the bimolecular triplet decay takes place during the flash. Anionic micelles have no influence on the triplet decay processes of erythrosine.
13C‐NMR‐spektroskopische Analyse von Gemischen Isomerer Alkyl‐4‐butylmorpholine
Authors: Schiefer H. , Beger J. , Scheller D. , Grossmann G.
Published: December 2004

13C‐N.M.R. Spectroscopical Analysis of Mixtures of Isomeric Alkyl‐4‐butylmorpholines

Mixtures of isomeric alkyl‐4‐butylmorpholines 3 were prepared by the treatment of several 2,2′‐dichloroalkyl ethers 1 (from the chlorination of alk‐1‐enes in the presence of ethylene oxide or propylene oxide) with butylamine and distinguished by 13C‐n.m.r. The distribution of isomers of 3 is not changed in relation to that of 1 except 3g,g′.
Vibronisches Spektralverhalten von Molekülen. VI. Theoretische Untersuchungen zur Molekülgeometrie und Spektroskopie des Perylens
Authors: Gustav K. , Seydenschwanz C.
Published: December 2004

Vibronic Spectral Behaviour of Molecules. VI. Theoretical Investigations on the Molecular Geometry and Spectroscopy of Perylene

The theoretical completely‐optimized molecular geometries of perylene are presented for the electronic states S0, S1 and T1. On this basis, the vibronic spectral behaviour in absorption and fluorescence has been calculated within the framework of the CONDON approximation. The results obtained are compared with the experimental S0‐S1 absorption and fluorescence and interpreted. The calculated geometry changes determine the significant active modes responsible for the fine structure of the corresponding spectroscopic transitions.
Bildung von Azoolefinen durch Umsetzung von Hydrazinen mit Amino‐hydroxy‐hydrobenzoxazol
Authors: Bischoff Christian , Schröder Edith
Published: December 2004

About the Reaction between Hydrazines and Aminohydroxy‐hydrobenzoxazol. Synthesis of Azoolefines

By the reaction of 1‐hydroxy‐2‐oxocyclohexane‐carboxamide (1) with cyanamide 2‐amino‐7a‐carbamoyl‐3a‐hydroxy‐3a,4a,5,6,7,7a‐hexahydrobenzoxazole (2) is formed. Compound 2 and arylhydrazine‐hydrochloride yield 1‐carbamoyl‐2‐arylazocyclohex‐1‐ene (4a, b). In morpholine azocompounds 4a, b rearrange to hydrazones 5a, b. Compound 2 and hydrazine yield 4‐(2‐carbamoyl‐cyclohexyl)‐semicarbazide (10), 10 forms perhydroquinazoline‐2,4‐dione (11) by oxidation with iodine. 2 and cyanic acid yield the urea derivative 12. 2 and arylamine‐hydrochloride afford the 2‐arylamino‐3a‐hydroxy‐7a‐carbamoyl‐hexahydrobenzoxazoles 13a, b. By fragmentation and “Dimroth‐rearrangement” of 2 tetrahydrobenzoimidazolone, (14) is formed, 12 gives 1‐carbamoyl‐tetrahydrobenzoimidazolone (15). 2 and m‐nitrobenzaldehyde yield “Schiff‐base” 16. 2 and hydroxylamine sulphate form 2′‐amino‐2‐hydroximino‐cyclohexane‐spiro‐5′‐oxazolin‐4′‐one (18) 18 and phenylhydrazine hydrochloride yield 1‐phenylazo‐2‐ureido‐carboxy‐cyclohex‐1‐ene (19).
Addition of arylureas to aroyl isothiocyanates and the synthesis of 1‐aroyl‐5‐aryl‐2‐thiobiurets and 2‐aryl‐5‐aroylamino‐2,3‐dihydro‐1,2,4‐thiadiazol‐3‐ones
Authors: Fouli F. A. , Shaban M. E. , Youssef A. S. A.
Published: December 2004

The hitherto unknown 1‐aroyl‐5‐aryl‐2‐thiobiurets (5a–h) were synthesized by addition of mono arylureas (4) to aroyl isothiocyanates (3). Treatment of 1‐aroyl‐5‐aryl‐2‐thiobiurets (5a–h) with alkali gave 5‐aryl‐2‐thiobiurets (6a–e). Oxidation of 1‐aroyl‐5‐aryl‐2‐thiobiurets (5d, f, h) with hydrogen peroxide in the presence of hydrochloric acid or bromine in chloroform gave 2‐aryl‐5‐aroylamino‐2,3‐dihydro‐1,2,4‐thiadiazol‐3‐ones (7a–c).