bluuebunny/crossref_metadata_2025 huggingface dataset:
Massenspektroskopische Untersuchungen von 5‐halogenierten Pyrimidinglucuroniden
Authors: Mahrwald Rainer , Schwarz Wolfgang
Published: December 2004

Mass Spectroscopy of 5‐Halogenated Pyrimidinglucuronides

Using the ion source according to von ARDENNE, useful spectra of negative and positive ions from sensitive glycosides were obtained either by electron attachment (EA‐) or low voltage electron impact (EI‐) mass spectroscopy.

Spectra of glucuronides derived from 5‐halogenated uracil, 2‐thiouracil, 4‐thiouracil and 6‐mercaptopurin in their peracetylated, esterified and free acidic form are described. Most stable peracetylated 2‐ and 4‐thiouracil glucuronides reveal intensive peaks of molecule ions.

The halogen‐carbon bonding strength, calculated from complementary aglycon peaks, demonstrates expected tendencies due to the halogen.
Zur Rolle von EDA‐Komplexen bei kationischen Polymerisationen. IX. Zum Lösungsmitteleinfluß auf Die Komplexbildung des kationischen Kettenendes mit Monomeren
Authors: Heublein G. , Spange S.
Published: December 2004

On the Role of EDA‐Complexes in Cationic Polymerization. IX. The Solvent Influence on the Complex Formation of Monomeres with Cationic Chain End

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

Derivatives of Imidazolidines from Oxalic Amidines

Tetraarylsubstituted oxalic amidines 1 react with acyl chlorides, phosgene, thiophosgene, chlorocarbonylsulfenylchloride, isocyaniddichlorides, and N‐aroyl‐1‐chlorothio‐formimidoylchlorides 7 to give the corresponding 5‐membered heterocycles 3, 4, 5 and 8.

Isocyanates 9 and isothiocyanates 10 react with oxalic amidines to yield imidazolidines 11, 12 and ureas 13, 14.

Hydrolysis of 3–5, 8, 11, 12 leads to the corresponding oxo compounds 15, 16.
Untersuchung der sensibilisierten Photolyse von 2‐Diazo‐1‐oxo‐1,2‐dihydronaphthalenen in fester Schicht
Authors: Böttcher H. , Marx D. R. J. , Lukas J. , Strehmel B.
Published: December 2004

Studies on the Sensitized Photolysis of 2‐Diazo‐1‐oxo‐1,2‐dihydronaphthalenes in Solid Layers

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

Photochemistry of Arylsubstituted Δ2‐1,3,4‐Oxadiazolines. II. The Influence of the Substituents and the Solvent on the Absorption and Fluorescence Properties of Arylsubstituted Δ2‐1,3,4‐Oxadiazolines

The electronic absorption and the fluorescence spectra of 16 arylsubstituted Δ2‐1,3,4‐oxadiazolines were measured in benzene at room temperature.

The push‐pull effect of the substituents supports an increasing intramolecular charge‐transfer in the electronically excited singlet state, which increases its dipole moment relative to the ground state.

The significant linear correlation of the Hammett σp‐values with the energies of the fluorescence and absorption maxima of the Δ2‐oxadiazolines, p‐substituted in the phenylring at the C 2‐atom, demonstrate these intramolecular charge transfer.

The titel compounds demonstrate with increasing solvent polarity a bathochromic shift of the absorption maxima.

For some oxadiazolines the dipole moment for the excited singlet state proved to be about 30 Cm as Stoke's shift dipendency from the solvent indicate.
Tetrathiafulvalene. XVI. Spektroskopische und elektrische Eigenschaften von TTF und TTF‐TCNQ‐Komplexen
Authors: Schukat G. , Fanghänel E. , Chyla A.
Published: December 2004

Tetrathiafulvalenes. XVI. Spectroscopic and Electrical Properties of TTF and TTF‐TCNQ‐Complexes

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

Prostaglandins and Prostaglandin Intermediates. Oxidative Cleavage of Olefins by Ozonization and Oxidation in the Solvent System Acetone/tert. Butanol – a Method for Preparation of Substituted Cyclopentyl Acetic Acids

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

About the Deactivation Behaviour of Photoexcited Aryltropyliumions. II. Fluorescence Quenching of Aryltropyliumions

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

3‐Nitromethyl‐pyrazoles from 2‐Cyano‐3‐methylthio‐4‐nitrocrotonic Acid Derivatives

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

Kinetic Investigations of the Pyrolysis of Mono‐n‐alkyl‐cyclohexanes

The thermal decomposition of cyclohexane and six mono‐n‐alkylcyclohexanes was studied kinetically in a metallic laboratory tubular reactor at 650 to 850°C and atmospheric pressure.

Kinetic parameters were found to be a function of length of the alkylic side chain. A comparison with analogous parameters of n‐paraffins and the unsubstituted cyclohexane allowed the conclusion that CC‐scission in the alkylic chain is the initial reaction in pyrolysis of n‐alkylcyclohexanes followed by radical attacks to all CH‐bonds of the feed molecules.
Grafische und numerische Analyse Temperaturabhängiger Fluoreszenzquantenausbeuten
Authors: von Löwis of Menar Michael , Bendig Jürgen , Siegmund Manfred
Published: December 2004

Graphical and Numerical Analysis of Temperature Dependent Fluorescence Quantum Yields

The graphical and numerical analysis of temperature dependent fluorescence quantum yields is a suitable method to derive the number and the temperature behaviour of various radiationless processes which are involved in the deactivation of a fluorescent excited state.

In this paper eight fluorophore/solvent‐systems were analysed, (T from 77K to 320 K) both, numerically and graphically. A computer program (SLAMS) was developed. It bases on a nonlinear regression and produces deactivation parameters and statements concerning the statistics of data, too. The possibilities, preferences and limits of the numerical analysis are discussed in comparison with the graphical method. The calculated results are discussed with regard to the number of radiationless processes, the accuracy of the quantum yield determination and the investigated temperature range.

For the physical interpretation of the kinetic parameters of deactivation in addition to the authors results values from the literature were used.
Photochemische Primärprozesse von Xanthenfarbstoffen. II. Blitzlichtspektroskopische Untersuchungen zum Einfluß von anionischen Mizellen auf die photochemischen Primärprozesse von Selenopyronin
Authors: Ortmann W. , Kassem A. , Fanghänel E.
Published: December 2004

Photochemical Primary Processes of Xanthene Dyes. II. Investigations of the Influence of Anionic Micelles on the Primary Processes of Selenopyronine by Flash Excitation

In aqueous solutions containing anionic micelles, the dye cations of selenopyronine are present at the micellar surface. If the concentration of the dye ions is much lower than the concentration of micelles, only monomolecular triplet decay (k1aM = 2 · 10−3s−1) is observed. Under these conditions, the half‐oxidized and half‐reduced form of selenopyronin is not formed. If the concentration of the dye ions is much higher than the concentration of micelles, two or more dye ions are present at every micelle, and a fast bimolecular decay of the triplet state during the flash is observed. The quenching of the triplet state with p‐benzoquinone (k7aM = 1,9 · 109 l/mol s), DABCO (k10aM = 1,6 · 107 l/mol s) and EDTA (k11aM = 1,3 · 105 l/mol s) and the decay processes of the half‐reduced and half‐oxidized form in the micellar solution are investigated.
3‐α‐Bromacetyl‐cumarine als Synthesebausteine für Heterocyclisch substituierte Cumarine
Authors: Czerney P. , Hartmann H.
Published: December 2004

3‐α‐Bromacetyl‐coumarines as Synthones for Heterocyclic Substituted Coumarines

3‐α‐Bromacetyl‐coumarines 2 react easily and in high yields with thiourea and thioamide derivatives 3 and 5, resp., to 4‐coumar‐3′‐yl‐thiazoles 4 and 6, resp., as well as with N,N‐disubstituted thioamides 11 and N,N,N′,N′‐tetraalkylthiourea 12 to 5‐coumar‐3′‐yl‐oxathioliumsalts 13 and 14, respectively. In a two‐step reaction 2 can be transformed by reaction with aniline 17 to 4‐coumar‐3′‐yl‐imidazoles 21 and 5‐coumar‐3′‐yl‐oxazoliumsalts 22, resp., via aminoketone intermediates 18.
Pyryliumverbindungen. XVIII, 2‐Alkoxy‐2H‐pyrane aus tetra‐ und pentasubstituierten Pyryliumsalzen
Authors: Fischer Gerhard W. , Zimmermann Thomas , Weissenfels Manfred
Published: December 2004

Pyrylium Compounds. XVIII. 2‐Alkoxy‐2H‐pyrans from Tetra‐ and Pentasubstituted Pyrylium Salts

Alkali alkoxides add regioselectively to 2,3,4,6‐tetrasubstituted pyrylium salts 7 (R' H), affording high yields of colourless crystalline 2‐alkoxy‐2H‐pyrans 9. The latte are also formed simply on refluxing 7 in the corresponding alcohol with triethylamine as proton acceptor. 3,5‐Dialkylsubstituted 2,4,6‐triarylpyrylium salts react analogously. The 2H‐pyran structure of the adducts obtained follows from their n.m.r., i.r., u.v. and mass spectra as well as from their reaction with tetracyanoethylene to cycloadducts of type 10. Acids regenerate from 9 the original pyrylium cations, whereas reaction of 9 with nitromethane or ethyl cyanoacetate provides benzene derivatives. ‐‐ The novel starting pyrylium salts 7b‐‐o are characterized by u.v./vis data and by transformation into the corresponding pyridine derivatives
Effect of metal ions in organic synthesis. XI. Hydrolysis and Alcoholysis of Some Acylhydrazines and N‐acyl‐N′‐arenesulphonylhydrazines in the presence of copper(II) chloride
Authors: Attanasi Orazio , Serra‐Zanetti Franco , Battistoni Paolo , Fava Gabriele
Published: December 2004

Zur Wirkung von Metallionen in der organischen Synthese. XI. Hydrolyse und Alkoholyse einiger Acylhydrazine und N‐Acyl‐N′‐arensulfonylhydrazine in Gegenwart von Kupfer (II)‐chlorid

Die Hydrolyse und Alkoholyse einiger Acylhydrazine und N‐Acyl‐N′‐arensulfonylhydrazine in Gegenwart von Kupfer(II)‐chlorid · 2 H2O wurden untersucht. Das Mesitylensulfonylhydrazid und die 2,4,6‐Triisopropylbenzensulfonylhydrazid‐Derivate sind reaktiver als die entsprechenden Hydrazine oder Tosylhydrazid‐Derivate.

Die entsprechenden Carbonsäuren und Ester erhält man in guten Ausbeuten und unter sehr milden Bedingungen. Die vorliegende Methode ist einfach und bequem im Vergleich zu anderen Methoden. Die Reaktion verläuft wahrscheinlich über Kupferkomplexe der Acylhydrazine.
1,3‐Dipolar Cycloaddition Reactions between some C‐aryl nitrogen oxides with electron‐deficient dipolarophils
Authors: Nour‐El‐Din Ahmed M. , Mourad Aboul‐Fetouh E.
Published: December 2004

Both C‐(2‐methylphenyl)‐N‐phenyl and C‐(3‐methylphenyl)‐N‐phenyl nitrones (1a, b) reacted with N‐phenylmaleinimide and fumaronitrile to give the normal primary cycloadducts. The reaction of the two nitrones (1a, b) with 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione and diacetylacetylene afforded rearrangement products. The unexpected 1,3,4‐oxadiazolidin‐2‐ones were isolated from reaction with phenylisocyanate. In contrast, tetracyanoethylene forms charge‐transfer complexes with both nitrones instead of cycloaddition products. The structural elucidation of the reaction products was made on the bases of the elemental analysis as well as i.r. and 1H‐n.m.r. spectral data.
Tetrathiafulvalene. XIX. Synthese und Eigenschaften elektronenleitender Poly‐Dithiolenkomplexe mit Ethylentetrathiolat und Tetrathiafulvalentetrathiolat als Brückenliganden
Authors: Poleschner H. , John W. , Hoppe F. , Fanghänel E. , Roth S.
Published: December 2004

Tetrathiafulvalenes. XIX. Synthesis and Properties of Electron Conducting Poly‐Dithiolene Complexes with Ethylene Tetrathiolat and Tetrathiafulvalene Tetrathiolat as Bridge Ligands

[1,3]‐Dithiolo[4,5‐d]‐1,3‐dithiol‐2,5‐dione7and 5‐(5‐oxo[1,3]‐dithiolo[4,5–d]1,3‐dithiole‐2‐ylidene)[1,3]‐dithiolo[4,5–d]1,3–dithiol‐2‐one8were synthesised from 1,3‐dithiole‐2‐thione‐4,5‐dithiolat. The ligands react with salts of iron, cobalt, nickel, palladium, platinum and copper to give the polymer complexes22a–gand23a–e, respectively. Irradiation of7in the presence of iron penta‐, dicobalt octa‐ or nickel tetracarbonyl gives the corresponding dithiolene complexes21a–c.

The amorphous insoluble polymer complexes from types21, 22, and23have been characterised by i.r.‐spectroscopy, susceptibility and conductivity measurements.

The nickel complexes have the highest electrical conductivity (σRT∼ 10−1Ω−1cm−1, pellets) with a very low activation energy (0,045 eV, 100–300 K)

A high electron delocalization in the direction of the polymer chain and an easy charge transfer from chain to chain is supposed.
Mehrfunktionelle N‐Tenside. VII. Substitution und Eliminierung bei der Reaktion von 1,2‐Dihalogenalkanen mit Aminen
Authors: Beger J. , Meerbote E.
Published: December 2004

Polyfunctionalized N‐Tensides. VII. Substitution and Elimination in the Reaction of 1,2‐Dihalogenoalkanes with Amines

1, 2‐Dichloroalkanes, 1, 2‐dibromoalkanes and mixtures of 1‐bromo‐2‐chloroalkanes and 1‐chloro‐2‐bromoalkanes react with primary or secondary amines and give both elimination and substitution products, often in a nearly 1:1 proportion.

The elimination products are the cis and trans‐1‐halo‐1‐alkenes, the 2‐halo‐1‐alkenes, the 1,3‐and 2, 4‐dienes and the 1‐alkenes. The main substitution products are the 1, 2‐bis‐aminoalkanes. Physical dates, 1H‐n.m.r.‐spectra, surface tension values and CMC‐dates are given.
Thermitase – eine thermostabile Serinprotease. II. Synthese von substratanalogen Peptidchlormethylketonen als potentielle irreversible Enzyminhibitoren
Authors: Jahreis Günther , Smalla Kornelia , Fittkau Siegfried
Published: December 2004

Thermitase – A Thermostable Serine Protease. II. Synthesis of Substrate Analogous Peptide Chloromethyl Ketones as Irreversibly Acting Inhibitors

The preparation of dipeptide to pentapeptide chloromethyl ketones of alanine wth variation of the amino acid in the P1 and P2 position

Nomenklatur für die individuellen Aminosäurereste der Peptide nach I. Schechter u. A. C. Berger, Biochem. Biophys. Res. Commun. 27, 157 (1967).

of the peptides is described. The synthesis is performed by fragment condensation of N‐acylated amino acids or peptides with the unprotected chloromethyl ketone derivatives of amino acids and peptides, respectively. Some examples of enzyme inactivation by peptide chloromethyl ketones are discussed.
The Autoxidation of 1‐Phenylalk‐1‐ynes. Proof of oxirenes as intermediates in the oxidation of acetylenes
Authors: Dao Le Thi Anh , Blau Karla , Pritzkow Wilhelm , Schmidt‐Renner Wolfgang , Voerckel Volkmar , Willecke Lothar
Published: December 2004

In the autoxidations of 1‐phenylprop‐1‐yne, 1‐phenylbut‐1‐yne, and 1‐phenyl‐3‐methylbut‐1‐yne a considerable attack at the CC triple bond takes place. Both products of the oxidative cleavage of the CC bond and products formed through the corresponding oxirenes were detected. The oxirenes rearrange via the isomeric ketocarbenes to ketenes, which yield the corresponding carboxylic acids or their esters. A part of the intermediate ketenes is oxidized with decarboxylation to lower ketones. All products were identified and quantitatively determined after LiAlH4 reduction to the corresponding alcohols.
Eine neue Synthese zur Darstellung von organischen Tellurverbindungen unter Verwendung von elektrochemisch erzeugten Polytelluriden
Authors: Merkel G. , Berge H. , Jeroschewski P.
Published: December 2004

A Novel Synthesis of Organic Tellurium Compounds by the Use of Electrochemically Generated Polytelluride‐ions

The cathodic polarisation of a tellurium electrode in aprotic solutions gives rise to polytelluride anions, which react with alkylhalides to the corresponding disubstituted ditellurides. By this method of electrosynthesis a number of organic ditellurides can be simply prepared and without danger. Dialkylditellurides of the general formula R‐Te‐Te‐R (2a–r) can be produced with high yields. The reaction with α,ω‐dihalides gives heterocycles, which involve one or two tellurium atoms in the ring (5a–d, 6–8). The electrochemical reduction of tellurium in the presence of methyliodid yields trimethyltelluroniumiodid (9).
Action of grignard reagents on 6‐(α‐styryl)pyridazin‐3(2H)‐ones; synthesis of some 4‐Substituted 6‐(α‐Styryl)‐pyridazin‐3(2H)‐ones
Authors: Ismail M. Fekry , Shams Nabil A. , El‐Khamry Abdel Momen A. , Mostafa Omnia E. A.
Published: December 2004

6(α‐Styryl)pyridazin‐3(2H)‐ones (1a–e) reacted with phenylmagnesium bromide and/or methylmagnesium iodide to give the 1,4‐addition products, 4‐phenyl and/or 4‐methyl‐6‐(α‐styryl)pyridazin‐3(2H)‐ones (3a–e). The structures assigned to the products are established by electronic and infrared spectroscopy and by synthesis of authentic samples in most cases.
Untersuchungen zum Photochromie‐ und Thermochromie‐Effekt an Benzilphenylhydrazonen
Authors: Müller U. , Timpe H.‐J. , Gustav K.
Published: December 2004

About the Photochromic and Thermochromic Effect of Benzil Phenylhydrazones

Benzil phenylhydrazone1synthesized from benzil and phenylhydrazine possesses s‐trans‐E configuration detected by means of quantum chemical calculations and its spectral data. Upon irradiation a photochromic process proceeds with a λ‐shift Δ λ ≈ 80 nm. The photoproduct has an s‐cis‐Z configuration. The quantum yields of the EZ‐isomerization measured by spectroscopic methods depend on solvent (ΦEZ= 0,077 in CH3OH, ΦEZ= 0,22 in n‐hexane), but are independent of the excitation wavelengths and O2. Benzil N‐methylphenylhydrazone2is inactive under stationary irradiation. Both the Z/E‐isomerization of1and2are be sensitized by benzil and m‐methoxyacetophenone. On the basis of kinetic measurements the quantum yields of sensitized reactions of1are calculated (Φ= 0,43; Φ= 0,57). In protic solvents benzil phenylhydrazone1has thermochromic properties caused by E/Z‐isomerizations. The measured activation parameters of these reactions are small. It is assumed that both the photoinduced and thermal isomerizations proceed via azo intermediates, as indicated by flash photolysis experiments.
2‐Arylamino‐thiophen‐3‐carbonsäurederivate
Authors: Schäfer H. , Jablokoff H. , Hentschel M. , Gewald K.
Published: December 2004

2‐Arylamino‐thiophene‐3‐carboxylic Acid Derivatives

The title compounds 3 are synthesized by reaction of 2‐amino‐thiophene‐3‐carboxylic acid derivatives 1 with anilines. The nucleophilic 5‐position in 3 allowed the synthesis of 5‐aryliden‐Δ3‐thiolen‐2‐one‐imines 5, 6 and the oxidative coupling to yield the azo compound 7. 1‐Aryl‐thieno‐[2,3‐d]pyrimid‐4‐ones 9, the thieno[2,3‐b]chinolin‐4‐one 10 and the 4‐chloro thieno[2,3‐b]chinolines 10, 11 can be obtained from 3.
Prostaglandins and prostaglandin intermediates. XV. Synthesis of 4‐Oxo Carboxylic Acids and γ‐Lactones by oxidative cleavage of homoallyl and homopropargyl ketones or alcohols
Authors: Schick H. , Welzel H.‐P. , Schwarz S. , Truckenbrodt G.
Published: December 2004

A convenient method to convert homoallyl or homopropargyl ketones or alcohols into 4‐oxo carboxylic acids or γ‐lactones is the oxidative cleavage of the multiple bond with potassium permanganate in diluted sulfuric acid. This is exemplified by the preparation of intermediates for the synthesis of 8‐methylprostaglandin C2. The oxidation of the allylic compounds with permanganate is compared with the oxidative cleavage by ozone/hydrogen peroxide, ozone/chromic acid or sodium periodate/potassium permanganate.
Photochemie diarylsubstituierter 2H‐Tetrazole. II. Zum Einfluß der Substituenten auf die Absorptionseigenschaften diarylsubstituierter Nitrilimine
Authors: Csongár Ch. , Leihkauf P. , Lohse V. , Tomaschewski G.
Published: December 2004

Photochemistry of Diarylsubstituted 2H‐Tetrazoles. II. The Influence of the Substituents on the Absorption Properties of Diarylsubstituted Nitrilimines

Irradation of 2,5‐diaryl‐2H‐tetrazoles in an EPA‐glass (ether: i‐pentan: ethanol=5:5:2) or in an i‐pentan glass at 77‐80 K with UV‐light of wavelength 290 nm yields diarylnitrilimines by the extrusion of nitrogen. The photoreactions investigated show spectroscopic unity. 22 diarylnitrilimines are included in the discussion with regards to the influence of substituents on the absorption maxima. The influence of substituents is interpreted by a LFE‐relationship. An intramolecular charge transfer as the reason for the relatively strong dependence of ν‐values on substituents is discussed.
Zur Herstellung von 1,3,4‐ Oxadiazol‐2‐carbonsäurederivaten
Authors: Dost J. , Heschel M. , Stein J.
Published: December 2004

Preparation of 1,3,4,‐Oxadiazol‐2‐carboxylic Acid Derivatives

The synthesis of 5‐substituted‐1,2,4‐oxadiazol‐2‐carboxylic acid derivatives 3a‐g and 4a‐g by cyclodehydratation of diacylhydrazines 1a‐g and 2a‐g are described. Further derivatives 6 to 9 are obtained from 1,3,4‐oxadiazol‐2‐carboxethyl esters 3.
Elektrochemische Reduktion von Trichloracetaldehyd‐Olefin‐Additionsprodukten
Authors: Voigtländer R. , Matschiner H. , Krzeminski Chr. , Biering H.
Published: December 2004

Electrochemical Reduction of Trichloroacetaldehyde‐Olefin‐Addition‐Products

Trichloroacetaldehyde reacts with different olefins forming addition products. In most cases this reaction results in 1, 1, 1‐trichloro‐2‐hydroxy compounds (2a–d). But also a different route of reaction is possible. Thus 2, 3‐dimethylbut‐1‐ene (1e) forms 4‐trichloro‐1, 1, 2‐tetrahydroxy‐furane (2e) and cyclohexene (1f) forms 3‐trichloromethyl‐2‐oxabicyclo‐2, 2, 2‐octane (2f).

All addition products are suitable starting materials for electrochemical conversions. In acidic electrolytes, on lead cathodes the electrochemical reduction results in a simultaneous cleavage of a CCl and a CO bond to form the CHCCl2‐group (3a‐f). In neutral electrolytes, on mercury cathodes, however, a reductive conversion of a CCl3 – group to a CHCl2‐group takes place (4c, 4f).
Untersuchungen zur Spin‐Trapping‐Kinetik in Systemen von Radikalen unterschiedlicher Reaktivität. Die Photolyse von α‐Phenylbenzoin in Gegenwart von Benzyliden‐tert.‐butylamin‐N‐oxid
Authors: Baumann H. , Timpe H.‐J. , Zubarev V. E. , Fok N. V. , Mel'nikov M. Y. , Raskasovskij Y. W.
Published: December 2004

Investigations on Spin‐Trapping Kineties in Radical Systems with Different Reactivity. Photolyses of α‐Phenylbenzoine in the Presence of Benzylideneter. ‐butylamine N‐oxide

As a model system to study the spin‐trapping kinetics of systems forming two radicals of different reactivity α‐phenylbenzoine (PhB) was chosen. The photolysis of PhB forms benzoyl (B·) and diphenylketylradikals (K·), respectively, which can be trapped by benzylidene‐tert‐butyl‐amine N‐oxide (PBN), as a spin trap. The rate constants of radical addition to PBN and their reactions with the spin adducts were determined by means of flash photolysis and kinetic calculations of the PBN concentration dependence. For B· and K· addtion rate constants to PBN of k1 = 8,1 × 105 M−1s−1, and k2 = 5,8 · 104 M−1s−1, respectively, were found. The rate constants for the reactions of B· and K· with the spin adducts are in the order of 109…1010 M−1s−1.
Lichtabsorption und Substituenteneffekte bei Stilben‐4‐diazoniumionen
Authors: Walkow F. , Epperlein J. , Mustroph H.
Published: December 2004

Light Absorption and Substituent Effects of Stibene‐4‐diazonium Ions

Substituent effects on ṽmax‐values of 31 stilbene‐4‐diazonium ions are studied. With increasing donor strength of a substituent in 4′‐position the long wave absorption band of stibene‐4‐diazonium ions shifts from the ultraviolet to the red region of the spectrum. The particular deep colour of diazonium compounds may be described by the very high σp‐Hammett‐constant of the diazonium group. The substituent effects found characterize stilbene diazonium ions as typical donor‐acceptor chromogenes.
Electronic Structure and Free‐Energy Relationships for Some 4′‐Substituted 4‐Dimethylamino trans‐Stilbenes by U.V. Photoelectron Spectroscopy
Authors: Cauletti C. , Furlani C. , Palma A. , Plancastelli M. N. , Schleinitz K. D. , Gloyna D.
Published: December 2004

A Series of 4′‐subsituted 4‐dimethylamino trans‐stilbenes 1‐5 was investigated by UPS, in connection with conjugated donor‐acceptor substituted double bond photochemistry. The measured and assigned spectra indicate a high sensitivity, depending on the changed electronic structure by 4′‐substituents of compounds 1‐5. Correlation of ionization energies in LFE‐relationship with Hammett's σp‐values and other ground state data was proved, demonstrating UPS a powerful tool for substituent effect studies in conjugated double bond systems.
s‐Triazolo[4,3‐a][1,3]diazacycloalkanes. I Synthesis and Reactions of 3‐Oxo‐2,3,5,6,7,8‐hexahydro‐s‐triazolo‐[4,3‐a]pyrimidine
Authors: Krȩżel Izabella
Published: December 2004

3‐Oxo‐2,3,5,6,7,8‐hexahydro‐s‐triazolo[4,3‐a]pyrimidine (5) was synthesized and its reactivity towards acylating reagents was examined. The assignment of tautomeric structures based on n.m.r. spectral data is discussed.
Pyryliumverbindungen. 31 [1]. Reaktion 3‐alkylsubstituierter 2,4,6‐Triaryl‐pyryliumsalze mit 1,3‐Diketonaten: Ein Weg zur Darstellung 3‐acylsubstituierter Benzophenone
Authors: Zimmermann Thomas , Fischer Gerhard W.
Published: December 2004

Pyrylium Compounds. 31. Reaction of 3‐Alkyl‐2,4,6‐triarylpyrylium Salts with 1,3‐Diketonates: A Method for the Preparation of 3‐Acylsubstituted Benzophenones

Reaction of 3‐alkyl‐2,4,6‐triarylpyrylium salts with 1,3‐diketones in the presence of one equivalent of triethylamine or potassium tert‐butoxide does not lead — as originally suspected — to the primary adducts of 2H‐pyran structure 6, but to the open‐chain valence isomers 7. Treatment of the latter with one equivalent of tert‐butoxide in tert‐butyl alcohol gives the same 3‐alkyl‐2,4,6‐triarylacetophenones 9 which are obtained directly from 5, 1,3‐diketones and two equivalents of potassium tert‐butoxide. However, on treating 7 with aqueous ethanolic sodium hydroxide 3‐acylsubstituted benzophenones 10 are formed in good yields. The reaction sequence 5→7→10 can also be performed through a one‐pot‐procedure. — The i.r., u.v., n.m.r. and mass spectroscopic data of the novel products 7, 9, and 10 are reported.
β‐Fur‐2‐yl‐α‐halogenacrylonitrile. V [1] Darstellung von β‐(5‐Nitro‐fur‐2‐yl)‐α‐azidoacrylonitril und β‐(5‐Nitro‐fur‐2‐yl)‐α‐aminoacrylonitril
Authors: Jähnisch K. , Gründemann E.
Published: December 2004

β‐Fur‐2‐yl‐α‐halogenacrylonitriles. V. Preparation of β‐(5‐Nitro‐fur‐2‐yl)‐α‐azidoacrylonitrile and β‐(5‐Nitro‐fur‐2‐yl)‐α‐aminoacrylonitrile

β‐(5‐Nitro‐fur‐2‐yl)‐α‐chloroacrylonitrile (1) reacts with sodium azide to yield β‐(5‐nitro‐fur‐2‐yl)‐α‐azidoacrylonitrile (2). By Staudinger‐reaction β‐(5‐nitro‐fur‐2‐yl)‐α‐aminoacrylonitrile (5) is formed. The 1H‐ and 13C‐n.m.r. spectra of E/Z isomers are discussed.
Kinetic Modelling of the Oxidation of Medium Paraffins further evidence for the importance of bifunctional intermediates
Authors: Engelmann Eleonore , Just Gerhard , Pritzkow Wilhelm , Rudolf Matthias , Spindler Gerald , Tien Tieu Dung , Voerckel Volkmar , Wittekind Volker
Published: December 2004

By computer simulation of the dependencies of the mole numbers of the ketones and alcohols derived from the starting paraffin, of the acids and esters, and in some cases also of the lower alkan‐2‐ones on the paraffin conversion relative rate constants were determined on the basis of a plausible kinetic model of the paraffin oxidation. The data obtained show that about 67% of the oxidation proceeds via bifunctional primary products. With the aid of the relative rate constants determined a good simulation of the experimental mole number‐conversion curves is possible.
α‐Aminoketone – Ein Beitrag zur Synthese optisch aktiver Derivate von Aminosäuren und Peptiden
Authors: Fittkau Siegfried , Jahreis Günther , Peters Klaus , Baláspiri Lajos
Published: December 2004

α‐Amino Ketones – A Contribution to the Synthesis of Optically Active Derivatives of Amino Acids and Peptides

The synthesis of N‐Z‐protected methyl ketones

Die Nomenklatur der Ketonderivate von Aminosäuren und Peptiden entspricht den IUPACIUB Nomenclature Recommendations 1983, Eur. J. Biochem. 138 (1984) 9. Um die Beziehung zu den Aminosäuren herzustellen, wird für Aminoaceton die Bezeichnung Glycylmethan GlyCH3 benutzt.

Weitere verwendete Abkürzungen: Z‐ = Benzyloxycarbonyl‐, E = Ether, PE = Petrolether, EE = Essigsäureethylester, CABE = Chlorameisensäure‐i‐butylester, TEA = Triethylamin, DMAP = 4‐Dimethyl‐aminopyridin, HMDS = Hexamethyldisiloxan, TMS = Tetramethylsilan, TRH = Thyreotropin Releasing Hormon, MSH‐RIF (MIF) = MSH‐Release‐Inhibiting‐Factor (MSH = Melanocyten stimulierendes Hormon).

from amino acids via the chloromethyl ketones and dehalogenation of the latter with zinc in glacial acetic acid is described. Deprotection of the methyl ketones results in the formation of hydrohalogenides of the α‐aminoalkyl methyl ketones further converted to N‐acylated peptide ketones as analogs of peptide hormones or as competitively acting substrate analogs of proteolytic enzymes. Aminoacetone is conveniently prepared as well as methyl‐pyrrolidyl ketone and methyl‐piperidyl ketone.
Synthesis and determination of the enantiomeric purity of (R)‐ and (S)‐2,3‐Dihydroxy‐3‐methylbutyl p‐Toluensulfonate
Authors: Schrötter Eberhard , Hauser Andre , Hamann Hans‐Jürgen , Schick Hans , Schönecker Bruno
Published: December 2004

(R)‐ and (S)‐2,3‐dihydroxy‐3‐methylbutyl p‐toluenesulfonate, used as building blocks for vitamine D3 metabolites and carotenoids, respectively, were resynthesized since differing melting points and optical rotations are reported in the literature. The given data of the (S)‐enantiomer could be corrected. A method for the determination of the enantiomeric purity was elaborated using the influence of a chiral lanthanide shift reagent on the 1H‐n.m.r. spectra of these compounds. By this way it was shown that both compounds exhibit an enantiomeric excess of more than 94%. The (S)‐enantiomer was synthesized according to an improved synthetic scheme starting from L‐serine.
Quantum chemical calculations of the molecular geometries and electronic absorption spectra of simple Cumulenes and Aza‐cumulenium Cations
Authors: Mehlhorn Achim
Published: December 2004

The molecular geometries in the electronic states S0and T1, heats of formation, singlet‐triplet splitting and transition energies of cumulenes and 1‐ and 2‐aza‐cumulenium cations up to chain lengths of 11 C‐atoms have been investigated by means of MINDO/3, CNDO/S and a modified PPP procedure. As far as experimental data are available their agreement with the theoretical results is satisfactory. This enables the molecular structure, the spectral behaviour and the colour of cumulated chains to be extrapolated up to chains of 20 C‐atoms. The properties of the cumulenes studied are compared with those of polyenes and polymethines and attempts were made to integrate cumulated chains within these classes of unsaturated chain molecules.
MO‐LCAO‐Berechnungen an schwefelhaltigen π‐Elektronensystemen. XLIX. Tetramethinverbrückte Oxalsäurederivate – neue farbige Pigmente von indigoider Struktur
Authors: Beckert R. , Fabian J.
Published: December 2004

MO‐LCAO Calculations on Sulfur‐containing π‐Electron Systems. XLIX. Tetramethine Bridged Derivatives of the Oxalic Acid – Novel Coloured Pigments of Indigoid Structure

Whereas thioamides react with the oxalylchloride to Δ2‐thiazoline‐4,5‐diones 1, which are precursors of the versatile thioacylisocyanate 2 synthons, the analogous reaction between thioamides and oxalyl‐bis(arylimidchlorides) completely fails. In the case of aliphatic thioamides the intermediate 2‐methyl‐Δ2‐thiazoline‐4,5‐diimides 3 undergo oxydative dimerization. The poorly soluble products are tetramethine bridged heteroanalogous oxalates 4 or isomers. The u.v./vis spectra of the blue compounds are in favour with structure 4 rather than with structure 6. This conclusion has been drawn from the results of Pariser‐Parr‐Pople(PPP) type calculations. According to the calculated position of the colour band of the pigments and of different molecular subunits, and the correspondence of their electronic states involved in the excitation, the dye molecules can be thought as consisting of two symmetrically crossed polymethine chains. This structural feature is inherent to the H indigo chromophore.
MO‐LCAO‐Berechnungen an schwefelhaltigen π‐Elektronensystemen. L. Synthese und UV/S‐spektrale Eigenschaften von 1H‐Perimidinthioncarbonsäurederivaten
Authors: Thiel W. , Fabian J. , Friebe B.
Published: December 2004

MO‐LCAO Calculations on Sulfur‐containing π‐Electron Systems. L. Synthesis and UV/VIS Spectral Properties of Derivatives of 1H‐Perimidine‐2‐thioncarbonic Acid

Esters of the 1H‐perimidine‐2‐dithiocarbonic acid are easily accessible from 1.8‐diamino‐naphthalene and chloroacetyl chloride and subsequent thiolation of the reaction product under mild conditions and alkylation. The dithioesters react with aliphatic and aromatic amines to form thioamides. Both the resulting dithioesters and thioamides are clearly distinguished by their colour from the vast majority of known derivatives of thioncarbonic acids. While dithioesters and thioamides are generally red and yellow, respectively, in solution the corresponding derivatives of the 1H‐perimidine are blue and red, respectively. The detailed examination of the experimental data has revealed that the colour determining longest wavelength absorption bands are due to the π→π* rather than to the n→π* transitions. Due to the efficient mixing of the lowest energy locally excited (LE) state of the heterocyclic moiety and the lowest energy perimidine‐to‐substituent charge transfer (CT) state the low‐intensity longwavelength π→π* transition of perimidine undergoes a pronounced red shift by acceptor substituents of high electron affinity in 2‐position. This interpretation of the deep colour of the 1H‐perimidine‐2‐thiocarbonic acid is in harmony with substituent effects and fully born out by Pariser‐Parr‐Pople(PPP) type calculations completed by additional analyses of electronic state (Baba‐Suzuki‐Takemura analysis) and electronic transitions (Ohta‐Kuroda‐Kunii analysis).
Exo‐ and endohormones. IX. Syntheses of Monounsaturated Sex Pheromones of Lepidoptera via 3‐alkyn‐1‐ols
Authors: Pop Lidia , Oprean I. , Barabas A. , Hodosan F.
Published: December 2004

3‐Alkyn‐1‐ols as intermediate synthons in the preparation of some Lepidoteran sex pheromones were utilized. Characteristic fragmentations reflecting the position of the triple bond were found in the mass spectra of 3‐alkyn‐1‐ols and alkyn‐1‐yl acetates in contrast to 1‐tert.‐butoxy‐alkynes. A partial isomerization of 1‐tosyloxy‐3‐(Z)‐octene to 1‐bromo‐3‐(E)‐octene within the reaction with NaBr in DMF was noticed by GC and 13C‐n.m.r., for which a mecanism involving homoconjugation in an intermediate non‐classical carbonium ion was suggested.
Versuche zur Synthese sterisch gehinderter Thiazylarene und deren Beziehung zu Arylsulfenylnitrenen
Authors: Mayer R. , Decker D. , Bleisch S. , Domschke G.
Published: December 2004

Attempts to Synthesize Sterically Hindered Thiazyl Arenes and Their Relationship to Arylsulfenyl Nitrenes

Up till now all attempts to synthesize organic thiazyl compounds in substance failed. Stabilization leads to the corresponding disulfide 2, the thioaminyl radical 7 and the sulphur diimide 8. Formally thiazyl compounds 1 and sulfenyl nitrenes 1 were resonance structures. Via sulfenyl nitrenes 1 the formation of 2, 7, 8 can be discussed. An in situ preparation of sulfenyl nitrene 1a via the sulfenyl chloride 5a, synthesized by chlorination of the disulfide 2a, and the sulfenyl azide 6a is described in detail. 1a can also be prepared from the sulfenyl amide 4a by oxidation. The structures of the radicals 7a–f and 12f are discussed.
1H‐NMR‐Untersuchung von Pyrido[1,2‐a]1,3,5‐triazinen: Through bond‐ und through space‐Effekte ringintegrierter Carbonyl‐, Thiocarbonyl‐ und Iminocarbonylgruppen
Authors: Bödeker J. , Köckritz A. , Köppel H.
Published: December 2004

1H‐N.M.R. Investigation of Pyrido [1.2‐a]1.3.5‐triazines: Through Bond and Through Space Effects of Ringintegrated Carbonyl, Thiocarbonyl, and Iminocarbonyl Groups

From the 1H‐n.m.r. spectra of pyrido[1.2‐a]1.3.5‐triazines 1a–i the characteristic data δ(H6), δ(H8), and J(H6, H7) are submitted. The ring‐integrated carbonyl groups in the position 2 (CX) show a deshielding electronic through bond effect on the protons H6 and H8 in the order of CNPh < CO < CS. On the other hand, the relative through space effect of these groups is in the order CO < CNPh < CS; this relation was determined by their deshielding influence in the position 4 (CY) on the peristanding proton H6. Finally the synthesis and the dissoziation behaviour of the new pyridotriazines 1d and 1h are described.
Exo‐ und Endohormone. XI. Synthese von monoolefinischen Sexualpheromonen der Lepidopteren über die α‐Diketone
Authors: Oprean I. , Ciupe Hilke , Gansca Lucia , Hodosan F.
Published: December 2004

Exo‐ and Endohormones. XI. Synthesis of Monounsaturated Sex Pheromones of Lepitopetra via α‐Diketones

α‐Diketones (5), prepared starting either with cyanohydrines (1) or with N,N‐diethyl oxamate (6), were converted via the dihydrazones (11) into acetylenes (12). Replacement of the protecting group by the acetate group and partial stereoselective reduction of the triple bond led finally to the title compounds.
The aldol reaction of substituted cyclopentane carbaldehydes with 2‐heptanone. A novel approach to the construction of the alkyl side chain of prostaglandins
Authors: Mahrwald Rainer , Schick Hans , Schwarz Sigfrid
Published: December 2004

The aldol reaction of suitably substituted cyclopentane carbaldehydes (1a–c, 4) with 2‐heptanone affords β‐hydroxy ketones (2a–c, 5) in yields up to 60%. These aldolization products can be dehydrated to known prostaglandin intermediates. Due to the difficulty to convert β,δ‐dihydroxy ketones selectively into α,β‐unsaturated δ‐hydroxy ketones this reaction sequence for the construction of the (E)‐3‐oxooct‐1‐enyl side chain of prostaglandins seems to be especially advantageous for the synthesis of 11‐deoxy‐prostaglandins.
Zur Alkylierung und Acylierung von 5‐Hydrazino‐1,2,3,4‐thiatriazolderivaten
Authors: Graubaum Heinz , Seeboth Helmuth
Published: December 2004

On Alkylation and Acylation of 5‐Hydrazino‐1,2,3,4‐thiatriazole Derivatives

5‐Hydrazino‐1,2,3,4‐thiatriazole reacts with oxo carboxylic acids to give highly unstable 5‐carboxyalkylidene‐hydrazino‐1,2,3,4‐thiatriazoles (2). The more stable 5‐alkylidenehydrazino‐1,2,3,4‐thiatriazoles (3) may be alkylated; the thiatriazole system is retained. On action of activated nitriles or isocyanates 1,2,4‐thiadiazole (6) or 1,2,4‐thiadiazoline derivatives (7) are formed with nitrogen evolution. At temperatures above 40°C, the described thiatriazoles decomposed to give undefinable components.
β‐Fur‐2‐yl‐α‐halogenacrylonitrile. VIII. Konformationsuntersuchungen an substituierten β‐Fur‐2‐yl‐acrylonitrilen
Authors: Hauser A. , Jähnisch K. , Kuban R. J.
Published: December 2004

β‐Fur‐2‐yl‐β‐halogenacrylonitriles. VIII. Investigations of the Conformation of Substituted β‐Fur‐2‐yl‐acrylonitriles

X‐ray analysis, n.m.r.‐investigations in the presence of Eu(FOD)3 and NOE‐measurement indicate, that the E‐isomer of β‐substituted β‐fur‐2‐yl‐acrylonitriles exist in the s‐cis conformation, whereas the E‐isomer of the α‐substituted β‐fur‐2‐yl‐acrylonitriles prefer the s‐trans‐conformation. The influence of the configuration and conformation on the chemical shift of the H‐3‐furan protons is discussed.
Synthese von bipolaren Ionenaustauscherharzen
Authors: Wolf F. , Eckert S. , Schwachula G. , Sabrowski E.
Published: December 2004

Synthesis of Bipolar Ion Exchange Resins

Syntheses of weakly acid/strongly basic and weakly acid/weakly basic bipolar ion exchange resins with varying acid and basic capacities via subsequent introduction of the exchange active groups in suitable crosslinked skeletal polymers are described.

Methylacrylate‐styrene‐divinylbenzene polymers of varying composition which can be quantitatively chloromethylated and subsequently fully aminated (trimethylamine) and partially saponified in one process step were used as starting polymers for weakly acid/strongly basic resins. The reverse route saponification of the ester groups first, followed by chloromethylation of the aromatic parts of the matrix and animation turned out to the possible, if at all, only for bipolar resins of strongly predominant basic character. The capacity parameters can be controlled through the composition of the matrix.

Polymethylacrylates crosslinked with divinylbenzene served as polymer basis of the weakly acid/weakly basic bipolar ion exchange resins. The functionalization was achieved by partial aminolysis with polyamines (dimethylaminopropylamine, ethylenediamine, diethylenetriamine) and saponification with lyes. The number of basic and acid groups which can be introduced is governed primarily by the conditions of the aminolysis. The capacity parameters are controllable within a broad range by the procedures.
Electronic Structure of Indandiones
Authors: Tyutyulkov N. , Tasseva M. , Georgiev E.
Published: December 2004

It is shown that the anions of the enolate forms of 1, 2‐ and 1, 3‐indandiones have antiaromatic character. This conclusion is reached after studying the geometry, the electron density distribution and the energy spectrum of the molecules.

The anion of the 1,2‐indandione enolate form is unstable because of strong electron‐vibronic interaction.
Anodic oxidation of 3‐amino‐5‐(pyrid‐4‐yl)‐1, 2‐dihydropyrid‐2‐one (amrinone)
Authors: Hagen V. , Klauschenz E. , Pragst F.
Published: December 2004

The anodic behavior of the cardiotonic drug 3‐amino‐5‐(pyrid‐4‐yl)‐1,2‐dihydropyrid‐2‐one 1 and of 6 compounds with similar structure was investigated at platinum and vitreous carbon electrodes in acetonitrile and in aqueous medium. Caused by the 3‐amino group 1 is oxidized at a relatively small oxidation potential in an irreversible two‐electron process. Depending on the addition of a strong base or a strong acid the oxidation potential vs. SCE in acetonitrile is −0.08 V (anion), +0.66 V (neutral compound), +0.93 V (monocation) or +1.15 V (dication). In H2O a strong decrease of the oxidation potential with increasing pH was found as a reason for the sensitivity of 1 against oxygen in alkaline solution. The anodic oxidation of 3‐dimethylamino‐5‐(pyrid‐4‐yl)‐1, 2‐dihydro‐pyrid‐2‐one 3 in 0.1 m H2SO4 leads to 5‐(pyrid‐4‐yl)‐piperidine‐2,3,6‐trione 9a or 5‐(pyrid‐4‐yl)‐piperidine‐2,3,4‐trione 9b, which is also the oxidation product of 1 at small concentration. At high concentration of 1 coupling reactions at the 3‐amino‐group lead to dimeric products, which could not be identified.
Characterization of Microemulsions
Authors: Sowada Rudolf , Hauthal Hermann G. , Grossklaus Simone
Published: December 2004

Microemulsions have been characterized by determining water uptake capacity as well as paraffin oil uptake capacity by nephelometric titration. The term “Hydrophile‐Lipophile Index” (abbreviated HLK) for the ratio water uptake capacity to oil uptake capacity has been proposed for the characterization of microemulsions. It has been shown that both water uptake capacity WA and oil uptake capacity 0A are temperature‐dependent quantities. The temperature
coefficients d WA/d T as well as d OA/d T may be: > 0; = 0; < 0. Based on these findings microemulsion systems of any composition, any origin or any application purpose is classified into nine categories.
EPR‐spektroskopische Charakterisierung der Assoziation von Cu(II)‐Komplexen vinyloger Amide
Authors: Ewert Uwe , Freyer Wolfgang
Published: December 2004

EPR‐Spectroscopic Characterization of Assoziating Cu(II)‐complexes of Vinylogic Amides

The e.s.r. spectra of glassy solutions of the Cu(II)‐complexes with different enaminone‐ligands were measured in dependence on substituents and solvent polarity.

CuCu distance and spatial angle α are calculated using the model of SMITH and PILBROW. In methylcylohexane only dimers could be detected. Two types of dimeric compounds were observed for which an interplane distance of r = 0.4 nm was calculated.

In dimeric Cu‐complexes of 4‐anilinomethylen‐δ2‐pyrazolin‐5‐ones the CuCu axis is perpendicular (α = 0°), in dimeric Cu‐complexes of anilinomethylenpentan‐2,4‐diones the CuCu‐axis is inclined (α = 35°).