bluuebunny/crossref_metadata_2025 huggingface dataset:
MO‐Berechnungen an substituierten Sydnonen. III. Quantenchemische Charakterisierung UV‐spektroskopisch beobachteter angeregter Zustände von Sydnonazomethinen
Authors: Sauer J. , Bauschke E. , Tomaschewski G.
Published: December 2004

Die gemessenen Elektronenspektren von Sydnonazomethinen werden mitgeteilt und auf der Basis von PPP‐Berechnungen zugeordnet. Die Annahme einer Verdrillung am Azomethin‐Stickstoffatom analog zum Benzalanilin ist mit den Resultaten in Einklang. Ausgehend von der Elektronenstruktur des Sydnons und durch Vergleich mit Benzalanilin und Sydnonäthylenen werden der Einfluß der Substitution in 3‐Stellung (R3 = CH3, C6H5, p‐CH3O‐C6H4), der Verlängerung des π‐Systems in 4‐Position, die cis‐trans‐Isomerie sowie die negative Solvatochromie diskutiert. Es zeigt sich, daß die Verknüpfung von Sydnonyl‐ und Azomethingruppe zu Systemen eigener Charakteristik führt. Die photochemischen Konsequenzen der berechneten Ladungsverteilungen werden aufgezeigt.
Asymmetrisch katalysierte Additionen von Thiolen an α‐Aminoacrylsäure‐ Derivate und Nitroolefine
Authors: Pracejus H. , Wilcke F.‐W. , Hanemann K.
Published: December 2004

Benzylmercaptan und andere Thiole lassen sich unter dem katalytischen Einfluβ optisch aktiver Basen (vorzugsweise Cinchona‐Alkaloide) asymmetrisch an die Doppelbindung von α‐Phthalimidoacrylsäureestern oder von 2‐Äthyl‐4‐methylen‐1,3‐oxazolinon‐(5) addieren, wobei optisch aktive Cysteinderivate in optischen Ausbeuten bis zu 54% erhalten werden. Ähnliche asymmetrische SH‐Additionen gelangen auch mit 2‐Nitrostyrol und 1‐Phenyl‐2‐nitropropen.
Kirkwoodsche Korrelationsfaktoren von binären Systemen mit Alkoholen und Diäthyläther
Authors: Rätzsch M. T. , Wohlfarth C. , Claudius M.
Published: December 2004

Die Theorie von KIRKWOOD erlaubt die Berechnung eines Korrelationsfaktors zur Beschreibung der Assoziation polarer Stoffe. Für die Systeme

n‐Hexan + Diäthyläther

Cyclohexan + Propanol‐(1)

Cyclohexan + Butanol‐(1)

Benzol + Methanol

Benzol + Äthanol

Benzol + Propanol‐(1)

Benzol + Butanol‐(1)

Benzol + Hexanol‐(1)

Benzol + Octanol‐(1)
werden die experimentell ermittelten Werte der Dielektrizitätskonstante (DK) sowie die berechneten Korrelationsfaktoren mitgeteilt.

Aus der Konzentrationsabhängigkeit der nach der KIRKWOOD‐FRÖHLICH‐Gleichung für Mischungen berechneten Korrelationsfaktoren ist für Methanol das Vorliegen weitverzweigter Assoziate, für Äthanol, Propanol‐(1), Butanol‐(1), Hexanol‐(1) und Octanol‐(1) Assoziation durch Clusterbildung zu schlußfolgern. Dabei liegt für die Systeme Benzol + Alkohol in den meisten Fällen der Schluß auf spezifische Wechselwirkungen zwischen den beiden Komponenten nahe.
Studies on the dissociation constants of benzoic acid and substituted benzoic acids in ethanol‐water mixtures by conductometric methods
Authors: Mandal A. K. , Lahiri S. C.
Published: December 2004

The dissociation constants of benzoic acid, m‐fluorobenzoic acid and m‐chlorobenzoic acid in water and ethanol‐water mixtures (8% to 87,6 wt.% of ethanol) have been determined by the conductometric method as suggested by Gelb with slight modification. The results hav been checked by the method suggested by FUOSS and KRAUS.
Säurekatalysierte Umsetzungen von Aromaten mit Alkanen und Cycloalkanen. VI. Alkylierungen mit niederen Alkanen (C3C5)
Authors: Miethchen Ralf , Gärtner Annelie , Roth Ulrich , Wiechert Kurt , Kröger Carl‐Friedrich
Published: December 2004

Benzol und Toluol lassen sich in Gegenwart von HF/SbF5, CF3SO3H/SbF5, HBr/AlBr3 oder CF3SO3H/AlBr3 mit Propan, n‐ und Isobutan sowie n‐ und Isopentan zu einem komplexen Gemisch von Alkylierungsprodukten umsetzen. Für derartige Alkylierungen findet zweckmäßig eine Gasumlaufapparatur Verwendung. Die mit dieser Apparatur erreichten Ergebnisse werden entsprechenden Umsetzungen im Autoklaven gegenübergestellt. Auf der Grundlage gaschromatographischer und massenspektrometrischer Analysen wird die qualitative und quantitative Zusammensetzung der Alkylierungsgemische aus Benzol und Isobutan angegeben.
Steroide. LIII. 1H‐NMR‐Untersuchungen. Konfigurationszuordnung von 16‐substituierten 17‐Hydroxy‐Steroiden
Authors: Schönecker B. , Tresselt D. , Draffehn J. , Ponsold K. , Engelhardt G. , Zeigan D. , Schneider Gy. , Weisz‐Vincze I. , Dombi Gy.
Published: December 2004

Die 1H‐NMR‐Spektren epimerer 16‐substituierter 17‐Hydroxy‐3‐methoxyöstra‐1,3,5(10)‐triene werden zur Konfigurationsbestimmung herangezogen. Aus der Kopplungskonstante J16,17 kann die Konfiguration eindeutig ermittelt werden, wenn die vier möglichen Epimeren mit gleichem 16‐Substituenten vorliegen. Liegt nur eine Verbindung vor, ist eine sichere Zuordnung allein durch J16,17 nur möglich, wenn J ≤ 2 Hz ist (16β,17α‐Konfiguration der Substituenten) oder wenn J > 8 Hz ist (16β,17β‐Konfiguration). Weitere zur Konfigurationsbestimmung geeignete Parameter sind die chemische Verschiebung der 13β‐Methylprotonen und die des 17‐Protons, die Tieffeldverschiebung dieses Signals nach Acetylierung oder nach „in situ”︁‐Reaktion mit Trichloracetylisocyanat sowie chemische Verschiebung und Gesamtaufspaltung des 16‐Protonensignals. Die Beiträge der 16‐Substituenten zur chemischen Verschiebung des 17‐Protons werden mit den aus 1‐substituierten Acenaphthenen erhaltenen Werten verglichen. Gleichungen zur Berechnung dieser Beiträge für die trans‐Verbindungen werden angegeben.
Aufklärung der Molekülstruktur von Rohölinhaltstoffen durch NMR‐Spektroskopie. III. Quantitative Analyse von Erdölfraktionen im Siedebereich über 220°C
Authors: Deutsch K.
Published: December 2004

Es wird eine Methode vorgestellt, die aus den Daten des 1H‐NMR‐Spektrums eine quantitative Analyse von Erdölprodukten im Siedebereich > 220°C erlaubt.

Außer den quantitativen Werten (Aromaten, Paraffine/Naphthene) werden für jede der beiden Stoffgruppen noch weitere Strukturinformationen geliefert (aromatischer Ringkohlenstoff, Substitutionsgrad der aromatischen Ringe, CH3‐Anteil der Paraffine/Naphthene).
1,2,3‐Triazabutadiene. V. Untersuchungen zum Mechanismus der thermischen cis‐trans‐Isomerisierung von substituierten 1‐Aryl‐3‐[methylbenzthiazolinyliden‐(2)]‐triazenen
Authors: Fanghänel E. , Hänsel R. , Hohlfeld J.
Published: December 2004

Die Geschwindigkeit der thermischen cis‐trans‐Isomerisierung von substituierten 1‐Aryl‐3‐[methylbenzthiazolinyliden‐(2)]‐triazenen wird in Abhängigkeit vom Substituenten im Aryl‐ bzw. Benzorest, von der Temperatur und dem Lösungsmittel bestimmt. Elektronen‐akzeptorsubstituenten in o‐ bzw. p‐Position des Arylrestes und Donatorsubstituenten in 6‐Stellung des Benzorestes erhöhen die Isomerisierungsgeschwindigkeit, ebenso polare Lösungsmittel und saure Katalysatoren. Im Arylrest donator‐substituierte bzw. in m‐Stellung akzeptor‐substituierte Derivate isomerisieren in Lösung unter den angewandten Bedingungen thermisch nicht. Aus den Untersuchungs‐ergebnissen wird auf einen polaren Rotationsmechanismus der Isomerisierung um die NN‐Doppelbindung der Triazabutadienkette geschlossen.
Struktur und Reaktivität heterosubstituierter Nitrile. XIX [1]. Kinetik und Mechanismus der Addition sekundärer aliphatischer Amine an Arylcyanate
Authors: Negoumy Sabry El , Bacaloglu Radu , Ostrogovich George , Martin Dieter
Published: December 2004

Die Addition sekundärer aliphatischer Amine an Arylcyanate zu N, N‐Dialkyl‐O‐aryl‐isoharnstoffen wurde in Dioxan und Dioxan‐Wassermischungen kinetisch verfolgt. Die Geschwindigkeitskonstanten sind linear von der Wasserkonzentration, der Basizität der Amine und der Elektrophilie der Arylcyanate abhängig. Aus den Daten und dem Vergleich der Aktivierungs‐parameter wird auf zwei Konkurrenzmechanismen geschlossen: direkter nucleophiler Angriff des Amins und Beteiligung eines Wassermoleküls an einem sechsgliedrigen Übergangszustand mit einem Amin‐ und Arylcyanatmolekül.
Elektrochemische Umlagerung von Papaverin und Dimerisierung zu 12, 12′‐Bis{2,3,9,10‐tetramethoxy‐indolo[2,1‐a]isochinolinyl}
Authors: Hess U. , Hiller K. , Schroeder Rita , Gründemann E.
Published: December 2004

Die präparative anodische Oxydation von Papaverin [6,7‐Dimethoxy‐1‐(3,4‐dimethoxy‐benzyl)isochinolin] in Methanol an Platinanoden führt unter Verlust von 3 Wasserstoffatomen pro Mol zu 12,12′‐Bis{2,3,9,10‐tetramethoxy‐indolo[2,1‐a]isochinolinyl}. Hierbei lagert sich die Benzyl‐isochinolinstruktur unter Abgabe von 2 H‐Atomen zu 2,3,9,10‐Tetramethoxy‐indolo[2,1‐a]isochinolin um, das durch weiteren Verlust je eines Protons und Elektrons am C‐Atom 12 dimerisiert. Es wird über voltammetrische Ergebnisse berichtet. 13C‐NMR‐spektroskopische Messungen weisen auf eine beträchtliche Verdrillung beider Molekülhälften hin.
Automatische Erfassung von Ionenausbeutekurven zur Bestimmung von Ionisations‐ und Auftrittspotentialen
Authors: Müller E.‐Ch. , Otto A. , Kraft R. , Etzold G.
Published: December 2004

Zur Bestimmung von Ionisations‐ und Auftrittspotentialen organischer Verbindungen aus Ionenausbeutekurven wurde ein Scangerät entwickelt, das die Energie der Stoßelektronen kontinuierlich von 30 auf 5 eV in ungefähr 30 Sekunden regelt. Gegenüber dem manuellen Verfahren erlaubt das vorgestellte System Scangerät‐Massenspektrometer‐Rechner eine etwa zehnmal schnellere Erfassung, Akkumulation und Ausgabe von Ionenausbeutekurven und damit auch die Untersuchung von thermisch wenig stabilen oder schnell verdampfenden Verbindungen.
Diskussion der EPR‐Spektren von Radikalanionen des TCNQ und TCNE auf der Basis von Solvensparametern
Authors: Stösser Reinhard , Siegmund Manfred
Published: December 2004

Die Bildung und Stabilisierung von Radikalanionen des TCNQ und TCNE sowohl aus den neutralen Akzeptoren als auch aus EDA‐Komplexen in Lösung wurde EPR‐spektroskopisch untersucht. Die z. T. erhebliche Abhängigkeit der Konzentration an gebildeten Radikalanionen, der Linienbreite der EPR‐Linien und der Auflösung der Hyperfeinstruktur von der Art des verwendeten Lösungsmittels konnte mittels ausgewählter Solvensparameter interpretiert werden. Als geeignete Parameter für die Radikalanionenbildung erwies sich hierbei die Donizität, während die Parameter Akzeptorzahl und die Größe δ, die der Energie zur Ausbildung eines Lösungsmittelkäfigs proportional ist, als Maßzahl für die Stabilisierung der gebildeten Radikalanionen in Lösung herangezogen werden konnten.
3C‐NMR‐Untersuchungen an Steroiden, III. Sterische Effekte von 2,3‐substituierten Cholestanderivaten und deren Anwendung zur Konfigurationsbestimmung
Authors: Engelhardt G. , Zeigan D. , Schönecker B.
Published: December 2004

13C‐N.M.R‐Investigations of Steroids. III. Steric Effects of 2,3 Substituted Cholestane Derivatives and their Application for the Configurational Analysis

The steric effects on 13C chemical shifts and their use for the determination of the substituent configuration of 5α and 5β‐cholestane (cholestane and coprostane), their 3‐OH derivatives and some 2‐mono‐ and 2,3‐disubstituted cholestanes are investigated. Because the substituent effect of the C8H17 group at C‐17 of cholestane and coprostane is very small for the carbon atoms of the rings A and B of the steroid skeleton, the discussed results are useful also for androstane derivatives with and without substitutions at the ring D.
Leitfähige Polymere mit Tetrathiafulvalenstruktur
Authors: Schukat G. , Van Hinh L. , Fanghänel E. , Libera L.
Published: December 2004

Conductive Polymers with Tetrathiafulvalene Structure

Synthesis and properties of phenylene‐ and biphenyl‐bridged polymer tetrathiafulvalenes are described. These polymers react with bromine or iodine and provide the radical‐cationhalides, whose electrical conductivity as powder compactions are estimated. The conductivity depends on stoichiometric composition of the radicale‐salts. The phenylene‐bridged polymer‐salts show a much higher conductivity than the biphenyl‐bridged ones and reach values of 10−3 ω−1 cm−1. The monomer salts have a higher conductivity than the polymer salts (max. 10−1 Ω−1 cm−1).
Pyrimidine Derivatives and Related Compounds. VIII [1]. Routes for the Synthesis of 3,5‐Diaminopyrazoles, 2‐Aminopyrazolo[1,5‐a]pyrimidines and 5‐Aminopyrazolo[1,5‐a]pyrimidines
Authors: Elnagdi Mohamed Helmy , Kandeel Ezzat Mohamed , Zayed Ezzat Mohamed , Kandil Zaghloul El‐Shahat
Published: December 2004

Pyrimidinderivate und verwandte Verbindungen. VIII. Neue Synthesemöglichkeiten für 3,5‐Diaminopyrazole, 2‐Aminopyrazolo[1,5‐a]‐pyrimidine und 5‐Aminopyrazolo‐[1,5‐a]‐pyrimidine

Während die 3,5‐Diacylamidopyrazole 2a–c durch Umsetzung von 3,5‐Diamino‐4‐phenylazopyrazolen 3 mit Schwefelsäure und Fettsäuren erhalten werden, entstehen die 3,5‐Diaminopyrazole 1 beim Erhitzen der Pyrazole 3 mit Schwefelsäure.

2‐Amino‐6,7‐dihydro‐5‐methyl‐7‐oxopyrazolo [1,5‐a] pyrimidin (4) erhält man durch Entfernung der Phenylazogruppe des leicht zugänglichen 3‐Phenylazoderivates 6.

Die 5‐Aminopyrazolo [1,5‐a] pyrimidinderivate 12a–c erhält man in guten Ausbeuten durch Reaktion der 5‐Aminopyrazole 10a–c mit Diethyl‐β‐amino‐β‐trichloromethylenmalonat 11a. Durch Reaktion von 11b mit 10b entsteht das 5‐Amino‐6‐cyanopyrazolo [1,5‐a] pyrimidinderivat 12d.
Reaktionen mit Cyclobutendionen. LIII [1]. Neue heterocyclische Systeme durch Umsetzung von 4‐[‐(z)‐Benzyliden]‐2,3‐diphenyl‐cyclobut‐2‐enon mit Diazomethan
Authors: Knorr Harald , Ried Walter , Knorr Ursula , Oremek Gerhard
Published: December 2004

Reaction of Cyclobutendiones. LIII. New Heterocyclic Systems by Reaction of 4‐[‐(z)‐Benzylidenene]‐2,3‐diphenyl‐cyclobut‐2‐enone with Diazomethane

The addition of diazomethane to stable 4‐alkylidene‐cyclobut‐2‐enones gives at the same time the 1:1 adducts 2, and under elimination of 1 mole nitrogene the 1:2 adducts 3 respectively the 1:3 adducts 4.
1,2,3‐Triazabutadiene. IX. 15N‐NMR‐spektroskopische Untersuchungen an cis‐trans‐isomeren 1‐Aryl‐3‐[3‐methylbenzthiazolinyliden‐(2)]‐triazenen und ‐triazeniumsalzen
Authors: Fanghänel E. , Radeglia R. , Hauptmann D. , Tyszkiewicz Brunhilde , Tyszkiewicz M.
Published: December 2004

1,2,3‐Triazabutadienes. IX. 15N‐NMR‐spectroscopic Investigations of Cis‐Trans‐Isomeric 1‐Aryl‐3‐[3‐methylbenzthiazolinyliden‐(2)]‐triazenes and ‐triazenium‐salts

The 15N‐chemical‐shifts and coupling constants of systematically 15N‐labeled cis‐trans‐isomeric 1,2,3‐triazabutadienes 1a–c and triazenium‐salts were determined and discussed with respect to the steric and electronic structure of the compounds. The chemical shifts correlate with the π‐electron density calculated in PPP‐approximation. The similarity of the chemical shifts and coupling constants of the respective alkylated and protonated compounds proves the preferred protonation of the trans triazabutadien chain in N1‐position.
Organische Phosphorverbindungen. XII [1]. Zum Hydrolyseverhalten von O,O‐Dimethyl‐O‐(1,2‐dibrom‐2,2‐dichlorethyl)‐phosphat (Naled)
Authors: Jentzsch Renate , Fischer Gerhard W.
Published: December 2004

Organic Phosphorus Compounds. XII. The Hydrolytic Behaviour of O,O‐Dimethyl O‐(1,2‐Dibromo‐2,2‐dichloroethyl) Phosphate (Naled)

The hydrolysis of Naled 2, an organophosphorus pesticide accessible by bromination of the enolphosphate Dichlorvos 1, in unbuffered aqueous solution does not only lead — as hitherto described — to dimethyl phosphate 3 and bromodichloroacetaldehyde 4 (path A), but also via intermediate formation of Desmethylnaled 5 to monomethyl phosphate 6 (path B). Kinetic measurements show that in the temperature range of 20–30°C both reactions proceed with similar velocities, and the primary step 2 → 5 determines the rate of path B. In comparison to Dichlorvos 1 the hydrolytic stability of Naled 2 has been found to be markedly lower. — The information on the degradation of Naled in unbuffered aqueous solution is completed by studies on the pH‐dependence of the hydrolysis and on the alkylation capacity of this pesticide.
Cyansäureester. 25 [1]. Umsetzung von Mercapto‐N‐heterocyclen mit Arylcyanaten
Authors: Martin Dieter , Wenzel Angelika , Bacaloglu Radu
Published: December 2004

Cyanic Acid Esters. 25 The Reaction of Mercapto‐N‐heterocycles with Aryl Cyanates

Unsaturated N‐heterocycles containing a cyclic thio urea structure and aryl cyanates (molar ratio 1:2), react to form azolo(1,2‐d) (1,2,4)thiadiazoles. This reaction has a wide scope concerning starting materials and gives good yields. Under the same conditions 2‐thione‐benzthiazolin is transformed to the corresponding disulfide. 4,5‐Bis‐mercaptomethylene‐o‐xylene and aryl cyanates give 2,3‐dithia‐6, 7‐dimethyl‐tetraline.
Oxidative Kupplung CH‐acider Verbindungen mit p‐Phenylendiaminen. II [1]. Reaktivität 4‐substituierter 1‐Hydroxy‐2‐naphthanilide gegenüber N,N‐Diethyl‐chinon‐(1,4)‐diimin
Authors: Mann G. , Wilde H. , Lehmann J. , Schindler W.
Published: December 2004

Oxidative Coupling of CH‐acid Compounds with p‐Phenylene Diamines. II. Reactivity of 4‐Substituted 1‐Hydroxy‐phenyl‐2‐naphthalene‐carboxamides with N,N‐Diethyl‐quinone‐(1,4)‐diamine

Substitution products of 1‐hydroxy‐N‐3,5‐(dimethoxycarbonyl)‐phenyl‐2‐naphthalenecarboxamide 1–16 with halogene, ‐OR, ‐SR and ‐NRR′ substituents in position 4 were synthesized. A great part of these compounds react with N,N‐diethyl‐quinone‐(1,4)‐diimine by elimination of the substituent giving the same indophenol dye which is received by oxidative coupling of the unsubstituted compound. Evidence about the degree of side reactions is obtained by measurement of dye yields.
Desaktivierungsverhalten von Arenen und Heteroarenen. XI. Nachweis strahlungslos desaktivierender Excimere durch Resonanzenergietransfer
Authors: Bendig J. , Kreysig D.
Published: December 2004

Deactivation Behaviour of Arenes and Heteroarenes. XI. The Evidence of Radiationless Deactivating Excimers by Resonance‐Energy Transfer

Investigations of resonance‐energy transfer in the systems of anthracene‐/ and akridizinium ion/rhodamine B (BF4) show, that in the case of high concentrations of energy donors the amount of the relative fluorescence quantum yield is greater than one. This result demonstrates the existence of a further energy donor, the excimer. In the case of the N‐methyl‐acridinium ion/ rhodamine B (BF4)‐system this fact cannot be observed, therefore a formation of excimers at high concentrations should be excluded. The existence (anthracene, akridizinium ion) and non‐existence (N‐methylacridinium ion) of excimers is in agreement with the ability of forming photodimers.
Selektive Umsetzungen von Kohlenhydraten mit Isocyanaten
Authors: Zinner H. , Langer T.
Published: December 2004

Selective Reactions of Carbohydrates with Isocyanates

6‐O‐Arylcarbamoyl‐D‐galactose dialkyl dithloacetals 2a–n are prepared by selective reactions of D‐galactose dialkyl dithioacetals with aryl isocyanates in pyridine. Some of them are acetylated to give the 2,3,4,5‐tetra‐O‐acetyl derivatives 3a, b, i–m. The structures of the compounds 2 and 3 are proved by further synthesis from 1,2;3,4‐di‐O‐isopropylidene‐D‐galactose or 2,3,4,5‐tetra‐O‐acetyl‐D‐galactose diethyl dithioacetal, respectively.
Reaktionen von Bis‐enaminen mit Aldehyden — Neue Synthesen für 1,3‐Oxazine und Pyridine
Authors: Adler B. , Burtzlaff Ch. , Duschek Ch. , Ohl J. , Schmidt H. , Zech W.
Published: December 2004

Reactions of Bis‐enamines with Aldehydes ‐ New Synthesis of 1,3‐Oxazines and Pyridines

In the presence of phosphoric acid N‐alkyl‐dipropenylamines react with aliphatic aldehydes to form substituted 1,3‐oxazines. With benzaldehyde this reaction does not proceed, but azomethines are formed. N,N‐dipropenylaniline with aldehydes also gives azomethines, a dihydropyridine is formed as well. From tripropenylamine and aldehydes substituted pyridines are obtained.
Action of Grignard Reagents on Mixed Biimides
Authors: Awad W. I. , Kandile N. G. , Ismail M. F.
Published: December 2004

Reaktion von Grignardverbindungen mit gemischten Diimiden

N‐Phthalimidosukzinimid 1 und N‐Phthalimidomaleinsäureimid 2 entstehen aus N‐Aminophthalimid und Succzinsäure‐ bzw. Maleinsäureanhydrid. 1 reagiert mit Grignardverbindungen zu den 3, 3‐disubstituierten Phthaliden 3 und N‐Aminosucczinimid. 2 reagiert mit Grignardverbindungen ebenfalls zu den Phthaliden 3 und einem schwer zu reinigenden Verbindungsgemisch. N‐Phthalimidomaleinsäureimid 2 reagiert leicht mit Diazoalkanen und Stickstoffwasserstoffsäure.
Analyse von technischem Diphenylolpropan (Dian) durch Schnelle Flüssigchromatographie
Authors: Eppert G. , Stief C. , Schinke I.
Published: December 2004

Analysis of Technical Diphenylolpropane (Bisphenol A) by High‐performance Liquid Chromatography

A method for the investigation of technical 2,2‐bis‐(4′‐hydroxyphenyl)‐propane (bisphenol A) by high‐performance liquid chromatography is described. Microspherical silicagel in unmodified (adsorption) and C16‐modified form (reversed phase) was used as support. It has been found that supports with small particle sizes (5 μm) achieve their optimum efficiency only when they possess an adequately narrow optimum particle size distribution.

The investigations were carried out using a self‐made apparatus. Details concerning an UV‐cell being insensitive to gas bubbles as well as a differential refractometer, which can be disassembled, are presented.
Untersuchungen zur Sulfochlorierung von Paraffinen. IV. Über die Sulfochlorierung von Isobutan
Authors: Kopinke F. D. , Kröckel W. , Pritzkow W. , Mateew K. , Radeglia R.
Published: December 2004

Studies on Sulphochlorination of Paraffins. IV. On the Sulphochlorination of Isobutane

In the sulphochlorination of isobutane at −20 to −10°C a mixture of 20–25% tert.‐butyl and 75–80% of isobutyl sulphochlorides is formed. The mixture has been analyzed by 1H‐ and by 13C‐n.m.r.‐spectroscopy. It is possible to transform the mixture of sulphochlorides into mixtures of the corresponding sulphonates, sulphonic acid methyl esters or sulphonic acid demithylamides. During the work‐up of the sulphochlorination mixtures it is necessary to keep the temperature low, because tertiary butyl sulphochloride is desulphonated at a noticeable rate already at temperatures above 35°C.
Quantenchemische Untersuchung der Cycloaddition von Phenol an Phenylcyanat als Beispiel für das Studium von MO‐Korrelationsdiagrammen im Falle der Abwesenheit von Symmetrieelementen im Übergangskomplex
Authors: Ritschl Friedrich
Published: December 2004

Quantum Chemical Investigation of the Cycloaddition of Phenol to Phenylcyanate as an Example for the Study of M.O. Correlation Diagrams of Systems without Symmetry Elements in the Transition State.

There is experimental evidence, that the N‐monomethylaniline‐catalyzed addition of phenol to phenylcyanate proceeds via a six‐membered, cyclic transition state, in which N‐mono‐methylaniline is involved, whose presence as a catalyst is necessary. In the present work is investigated by quantumchemical considerations, whether an analogy can be found between this reaction and a symmetry‐allowed [2 + 4]cycloaddition of π‐systems. Using the CNDO/2‐method an energy curve has been calculated, having only a small activation barrier. The wavefunctions at some points of the reaction coordinate have been localized to bond orbitals, which are then taken into some linear combinations. These do not show any change of their nodal behaviour at points belonging to the starting resp. to the final state of the reaction. This shows, that the above mentioned analogy is valid. For the [2 + 2]cycloaddition in absence of the catalyst, on the contrary, the energy curve shows a very high activation energy, and the nodal behaviour of the combined localized orbitals is changed on passing from the starting to the final state.
Synthese und Reaktionen von 2‐[Bis‐(alkylthio)‐methyliden]‐indan‐1,3‐dionen
Authors: Augustin M. , Groth Ch. , Kristen H. , Peseke K. , Wiechmann Ch.
Published: December 2004

Synthesis and Reactions of 2‐[Bis‐(alkylthio)‐methyliden]‐indan‐1,3‐diones

The 2‐[bis‐(alkylthio)‐methyliden]‐indan‐1,3‐diones 3 and especially the methyl‐compound 3a react with nucleophiles by substitution of the CH3Sgroup. The reaction with amines are yields the S,N or N,N‐acetales 7 and 8, respectively. Diamines, amino hydroxy‐ or amino‐mercapto compounds as dinucleophiles give the cyclic compounds 9 or the condensed heterocycles 12 and 16, where the carbonyl group has been integrated in the cyclisation. Also carbanions react with 3a under substitution. The structures of the final products are determined with ir‐, 1H‐n.m.r.‐ and ms‐spectra.
Tetrathiafulvalene. VII [1]. Arylenverbrückte polymere Tetrathiafulvalene
Authors: van Hinh Le , Schukat G. , Fanghänel E.
Published: December 2004

Tetrathiafulvalenes. VII. Arylene‐bridged Polymeric Tetrathiafulvalenes

Synthesis and properties of phenylene — and biphenylbridged polymeric tetrathiafulvalenes, which are substituted by two methyl‐groups in the 3‐ and 6‐position, are described. These polymers react with bromine, iodine or tetracyanoquinodimethane to form the radical cation salts, whose electrical conducticity are estimated by means of powder compactions. The differences in the conductivity of the TCNQ‐salts and radical cation halides are very small. The phenylene‐bridged polymer‐salts show a higher conductivity than the bi‐phenylylene‐bridged ones up to values of 10−3Ω−1 cm−1. Surprisingly the monomer salts have a lower conductivity than the polymer salts.
Quantenchemische Untersuchungen zur Farbe und Stereodynamik von acyclischen Azinen. IIZum Einfluß tordierter S0‐Molekülgeometrien auf das Spektralverhalten und den Photochromie‐Effekt des Benz‐ und Anthraldazins
Authors: Gustav K. , Vettermann S. , Rose I.
Published: December 2004

Quantum Chemical Study on Colour and Stereodynamics of Acyclic Azines. II. Influence of Twisted S0 Molecular Geometries on the Spectral Behaviour and the Photochromic Effect of Benz‐ and Anthraldazine

On the basis of quantum chemical calculations the influence of twisted molecular geometries on the spectral behaviour of (1E,3E)‐ and (1E,3Z)‐isomers of benz‐ and anthraldazine has been investigated. It is possible to point out structural peculiarities in the S0 state and to explain the photochromic effect of the arylsubstituted acyclic azines.
Propellanes. I. 3,6,10,13‐Tetrathia(4,5,11,12‐trans‐dicyclohexano)‐(6,6,1)propellane
Authors: Jamrozik Janusz
Published: December 2004

Propellane. I. 3,6,10,13‐Tetrathia(4,5,11,12‐trans‐dicyclohexano)‐(6,6,1)propellan

Durch Reaktion des 1,1,2,2‐Tetrabrommethylcyclopropans mit trans‐1,2‐Dimercaptocyclohexan wurde die tricyclische Verbindung 1 mit Propellan‐Struktur erhalten. Die Struktur dieser Verbindung wurde mit Hilfe spektroskopischer Daten und der Fragmentierung der Massenspektren ermittelt. Für die beiden achtgliedrigen Ringe wird eine “twist‐crown” Konformation vorgeschlagen. Die Oxidation des (6,6,1)Propellans 1 führt zu dem entsprechenden Tetrasulfon, in dem der Cyclopropan‐Ring erhalten bleibt.
Katodische Reduktion von Keten‐S,S‐acetalen
Authors: Rüttinger H.‐H. , Rudorf W.‐D. , Matschiner H.
Published: December 2004

Cathodic Reduction of Ketene S,S‐acetals

Ketene S,S‐acetals are reduced in protic media by the cleavage of one S‐alkyl group. The resulting carbanion either may be protonated or reacts with the starting material to yield dimers. The effects of different substituents on the half‐wave potentials and the rate constants of amination have been investigated.
MO‐LCAO‐Berechnungen an Polymethinen. XI Lokale spektrale Anregungen in polynuclearen Cyaninfarbstoffen
Authors: Fabian J. , Zimmer A.
Published: December 2004

MO‐LCAO Calculations on Polymethines. XI. Local Spectral Excitations in Polynuclear Cyanine Dyes

Various branched‐conjugated cyanine dyes display long‐wavelength absorption bands similar in position to those of their straight‐chain substructures. According to the analysis of results of PPP‐type calculations this close similarity results from a partial localization of the electronic transitions, whereas the participating electronic states are highly delocalized. The long‐wavelength absorptions of symmetrically‐branched trinuclear cyanine dyes have an entire molecular chromophore origin resulting from twofold degenerate electronic transitions. Lowering of the symmetry brings about a splitting of the colour‐band.

In contrast to the branched‐conjugated cyanine dyes various tetranuclear cyanine dyes can be considered as being composed of two subchromophores either directly linked or joined through a conjugative bridge. In accordance with PPP configuration analyses and LHM‐type calculations the splitting of the colour band is best understood by composite‐molecule approaches. In this context the applicability of the simple molecular exciton theory is discussed.
Zur Rolle von EDA‐Komplexen bei kationischen Polymerisationen. VI[1]. Wechselwirkung von Halogenidionen mit organischen aπ‐Elektronenacceptoren
Authors: Heublein GÜNther , Spange Stefan , Hallpap Peter
Published: December 2004

The Role of Donor‐Acceptor Complexes in Cationic Polymerisations. The Interaction of Halide Ions with Organic aπ‐Acceptors

The anions of salts of the type Kat+X− (Kat+  Li+, Na+, Et4N+; X−  Cl−, Br−, I−) form donor‐acceptor complexes with organic a π‐acceptors. The long‐wave charge‐transfer absorption show a bathochrome shift with higher periodic numbers of X− and increasing electron affinity of the acceptors Acc. Strong acceptors form radical ions very rapidly with X  I and slowly with X  Br. Cl.

The interactions in the system Kat+X− → Acc are influenced by solvents in a very complex way. As acceptors they interact preferably with the halide ion X− and, hence, reduce its donicity for the competing acceptor Acc. As donors they change the dissociation of the ion pair Kat+X− by solvation of the cation Kat+ and influence in that indirect way also the donicity of X− for the acceptor Acc.
Isostere Adsorptionswärme des Ethans an Zeolithen vom Typ NaX und NaY
Authors: Stach H. , Throl U. , Schirmer W.
Published: December 2004

Isosteric Heat of Adsorption of n‐Ethane on Zeolites NaX and NaY

Using a volumetric method isotherms of adsorption of ethane on zeolites NaX and NaY were measured. The Clausius‐Clapeyron equation was used to calculate the isosteric heat of adsorption of the paraffin on both molecular‐sieves. These enthalpies show a linear dependence of the amount of adsorbed molecules. The zeolite with the higher charge density shows a larger heat of adsorption. The difference in the heat of adsorption is explained by adsorption on different centers in the cavity of both zeolites.
Ionenpaareffekte bei der Photolyse und Thermolyse von Aryldiazonium‐tetrafluoroboraten
Authors: Becker H. G. O. , Israel G.
Published: December 2004

Ion Pair‐Effects in the Photolysis and Thermolysis of Arenediazonium Tetrafluoroborates

Fluoroarenes produced by Schiemann‐reaction of p‐methyl‐ and p‐tert.‐butyl‐benzenediazonium tetrafluoroborates in solution are formed mainly from ArN2+/BF4−‐ion pairs. The ratio of product yields formed from the reaction of arene cations with the solvent to the yields of fluoroarenes increases with increasing KD/α; KD is the conductometrically determined dissociation constant, and α the dissociation degree of ion pairs. The photochemical and thermal dediazoniation gives the same product ratios, indicating, that both sorts of reactions proceed via the same intermediate — the arene cation.
Synthese eines Insulin‐A‐Kettenfragmentes A14–21 mit der Diphenylmethyl‐Schutzgruppe am Cystein
Authors: Kaufmann K.‐D. , Schönherr C. H. , Jeschke C. , Bauschke S. , Kietzer M. , Dölling R.
Published: December 2004

Synthesis of an Insulin A‐Chain Fragment A14–21 with the Diphenylmethyl Protecting Group for Cysteine

The synthesis of the C‐terminal octapeptide of the insulin A‐chain, N‐2‐[biphenylyl‐(4)]‐propyl‐(2)‐oxycarbonyl‐O‐tert.‐butyl‐L‐tyrosyl‐L‐glutaminyl‐L‐leucyl‐γ‐tert.‐butyl‐L‐glutamyl‐L‐asparaginyl‐O‐tert.‐butyl‐L‐tyrosyl‐S‐diphenylmethyl‐L‐cysteinyl‐L‐asparagine‐tert.‐butylester, by conventional fragment condensations is described.
Tieftemperaturuntersuchungen zur Photochromie von Triphenylformazan
Authors: Langbein H.
Published: December 2004

Low‐Temperature Investigations of Photochromic Triphenylformazan.

Absorption spectra and photochromic behaviour of triphenylformazan‐isomers at low temperature have been investigated. It is shown, that the scheme of Kuhn and Weitz [13] is somewhat unsatisfying: Photoisomerization of triphenylformazan occurs only about the NN‐double bond, isomerization about the CN‐double bond is a thermal reaction. The absorption spectra of the two intermediates between the stable red form and the metastable yellow form have been calculated by the method of Fischer.

At low temperature the quantum yield of trans‐cis‐photoisomerization about the NN‐link of triphenylformazan becomes smaller. The cis‐trans‐isomerization is insensitive to changes in temperature.
Allgemeine Synthesen und rationelle Strukturparameter isomerer Derivate von [3,4]‐kondensierten Pyrazolen
Authors: Dorn Helmut , Ozegowski Rüdiger
Published: December 2004

General Syntheses and Rational Parameters for Structural Assignment of Isomeric Derivatives of [3,4]‐fused Pyrazoles

4 isomeric 1‐ or 2‐methyl‐, and 1‐ or 2‐benzyl‐pyrazolo[3,4‐b]pyridones, i.e. the 4‐oxo‐types17a, bor11a, band the 6‐oxo‐types16a, bor10a, b, are synthesized unambiguously. Cyclisation of 1‐substituted 3‐ or 5‐(1‐methyl‐2‐ethoxycarbonyl‐vinylamino)‐pyrazoles9a, bor.15a, b, which were synthesized from 1‐substituted 3‐ or 5‐amino‐pyrazoles and ethyl acetoacetate yields11a, bor17a, bin downtherm, but10a, bor16a, bin presence of acidic catalysts. The acidic cyclisation is preceded by a new rearrangement of9or15into 1‐ substituted 3‐27or 5‐amino‐4‐(1‐methyl‐2‐ethoxycarbonyl‐vinyl)‐pyrazoles30; mechanism and concurring reactions are explained. Because of their higher electron densities at C‐4 it is easier to cyclise derivatives of 5‐amino‐pyrazoles compared to 3‐amino‐pyrazoles. All isomeric 1‐ or 2‐substituted 4(6)‐chloro‐6(4)‐methyl‐pyrazolo‐[3,4‐b]pyridines are formed with POCl3from the corresponding oxo‐compounds.

The position of a substituent at N‐1 or N‐2 of [3,4]‐fused pyrazoles can be assigned using the significant1H‐n.m.r.‐parameter Δ= δ— − δHMPT(conc. HC—3). If solvent influences are considered, δ(C  O) is a useful13C‐n.m.r.‐parameter to distinguish the 4‐oxo‐types (11a, b; 17a, b) from the 6‐oxo‐types (10a, b; 16a, b) of pyrazolo[3,4‐b]pyridones. Further own and lit. dates conc. structural assignment (n.m.r., i.r., u.v.) are discussed critically.
Substituenteneffekte in den 13C–NMR‐Spektren von diastereomeren Chalkon‐dihalogeniden. I. Untersuchungen an diastereomeren Chalkondibromiden und Chalkonbromchloridaddukten
Authors: Weber Fritz Gerd , Radeglia Reiner
Published: December 2004

Substituent Effects in 13C‐N.M.R. Spectra of Diasteroemeric Chalcone Dihalogenides. I. Investigations of Diastereomeric Chalcone Dibromides and Bromochlorides Adducts

Fourier‐transform 13C‐n.m.r. spectra of two series of chalcone dihalogenides 1 und 2 including some pairs of diastereomeres are reported. All of the carbon resonances are assigned. Substituent effects on the chemical shifts of carbonyl‐, α‐ and β‐C‐atoms in dependence on the position of the substituent in ring A or B in both of systems are discussed. The dependence of chemical shifts on the erythro or threo configuration is studied.
Condensation of Aryl Benzyl Ketones with Dimethyl Diglycollate
Authors: El‐Newaihy M. F. , Salem M. R. , Enayat E. I. , Abdel‐Hamid H. A. , El‐Bassiouny F. A.
Published: December 2004

Kondensation von Arylbenzylketonen mit Dimethyldiglycollat

Phenyl‐, p‐Tolyl‐ und p‐Chlorphenyl‐benzylketone kondensieren mit Dimethyldiglycollat in Gegenwart von Natriumhydrid in guten Ausbeuten zu den entsprechenden Z‐Halbestern 2a–e. Struktur und Konfiguration der Halbester wurde durch chemische und spektroskopische Befunde gestützt.
Theoretische Untersuchungen zum elektrophilen Angriff. VIII. Das protonierte Pyrrol
Authors: Illek B. , Grimmer M. , Heidrich D.
Published: December 2004

Theoretical Studies to the Electrophilic Attack. VIII. The Protonated Pyrrole

The potential surface of protonated pyrrole was analysed for minima and saddle points of first and higher order by special numerical methods. The calculations were carried out on the basis of semiempirical methods tested in the past on related cationic systems.

The relative energies of face protonated pyrrole, the σ‐complexes and H‐bridged structures were compared with recent results on the benzene‐H+ system to interprete the H‐shifts in the cation and the intermediates in the proton exchange reaction. Theoretical suggestions for solvatation effects are considered in the discussion. One of the most striking results is the high barrier for the H‐shift from the N‐protonated form to the α‐position.
Spektroskopische und Dipolmoment‐Untersuchungen an Halogenfluorid‐Additionsprodukten der Chalkone
Authors: Weber Fritz Gerd , Giese Hartmut , Köppel Hubert
Published: December 2004

Spectroscopical and Dipole Moment Investigations of Halogen Fluoride Addition Products of Chalcones

Chalcone halogen fluoride addition products 1–3 are investigated in the i.r. and 1H‐n.m.r. spectroscopy field as well as in the substituent dependence of spectral parameters and molecular dipole moment. The assign of configuration and conformation on basis of 1H‐n.m.r. spectroscopy and dipole moments are discussed.
Über 3d‐Metallkomplexe von 2‐Hydrazinochinoxalinen
Authors: Schleinitz K.‐D. , Westphal G. , Surkau A. , Lochner D.
Published: December 2004

About 3d‐Metal‐Complexes of 2‐Hydrazinoquinoxalines

Some complexes of 3d‐metals and 2‐hydrazinoquinoxalines were synthetisized and characterized spectrometrically. These compounds probably exist in solution as tetragonal distorted octahedrons. The organic ligands are to be found at the quadratic base, and anions or solvent‐molecules, respectivily, at the tops of the octahedron. The existence of chelates can be concluded from i.r. spectra. Together with u.v./vis‐spectra back donation can be assumed. An assignment of the u.v./vis‐bands is suggested and the ligand‐field parameters Dq are estimated.
Azoperoxide. VI. Selektive Spaltungen von β‐Azo‐acylperoxiden
Authors: Schulz Manfred , West Gerd , Ourk Sakum , Strunz Ingo
Published: December 2004

Azoperoxides. VI. Selective Decomposition of β‐Azoacylperoxides

The selective decomposition of the OO‐Groups in the azoperoxides 1 and 2 is possible by reaction with dimethylaniline at 35°C. Rate constants were measured and the decomposition products were analyzed. Intermediates are azoalkyl radicals. The radical yield of the amine induced decomposition of 2 in ethylbenzene is 8.2% at 35°C.

UV irradiation of the azoperoxides 1 and 2 at 20°C in ethylbenzene results in a quantitative and selective decomposition of the azo groups. Intermediates are C‐radicals with intact peroxide groups. The reaction of 1 and 2 with triethylstannane yields reduction products of the OO‐groups and the NN‐groups, respectively.
Untersuchungen über die Autoxidation von cis‐ und trans‐β‐Methylstyren
Authors: Fuchs K. P. , Pritzkow W.
Published: December 2004

Studies on the Autoxidation of cis‐ und trans‐β‐Methyl Styrene

In the autoxidation of cis‐ and trans‐β‐methyl styrene at temperatures between 80 and 120°C the CC‐double bond is preferably attacked: 35–60% of epoxides and their consecutive products and 25–50% of benzaldehyde are obtained. Products of allylic oxidation are formed only with yields lower than 1%; high‐boiling or polymeric products, respectively, which could not be detected gaschromatographically are formed with yields lower than 20%. The ratio of cis‐ to trans‐epoxides in the case of cis‐β‐methyl styrene oxidation amounts to about 0.04, in the case of trans‐β‐methyl styrene oxidation this ratio is about 0.01.
Eine neue Synthese des Cinnamoyliminodithiokohlensäure‐S,S‐dimethylesters und Umsetzungen mit Nucleophilen
Authors: Richter M. , Herrmann C. , Augustin M.
Published: December 2004

New Synthesis of Dimethyl‐cinnamoylimino‐dithiocarboxylate and Reactions with Nucleophiles

A new general synthesis of dimethyl‐cinnamoylimino‐dithiocarboxylate 1d is possible by reaction of 4‐nitro‐cinnamoylamide with carbon disulfide in the presence of sodium hydride and following alkylation. With the unsubstituted dimethyl‐cinnamoylimino‐dithiocarboxylate 10 is in‐vestigated the reaction behavior with nucleophilic compounds. The treatment of 1c with primary amines, respectively, by mono‐ and disubstitution of the methylthio groups yields isothiourea 2 or guanidines 3. Benzocondensed heterocycles are formed by reaction of 1c with o‐bifunctional nucleo‐philes.

The compounds 5, 6 and 7 have been synthesized from 1c with cysteamine, p‐phenylenediamine and ethylenediamine.

The oxadiazole 8 and isothiosemicarbazide 9 are obtained by reaction of the dithioester 1c with hydrazides. On the other hand cyclisation to the 1,2,4‐triazole 11 over the intermediate 10 and to the 1,3,5‐triazine 12 are possible.

The reaction of 1c with carbanions in a basic medium affords acrylic derivatives 13.

In the same way we isolated by reaction of dithioester 1c with a benzothiazolium salt the dark coloured compound 14. The physical properties of synthesized compounds are discussed by mass‐, 1H‐n.m.r.‐, i.r.‐ and u.v.‐spectra.
Die Analytik von Kohlenwasserstoffen mit Hilfe der Massenspektrometrie. VIII. Stereochemische Einflüsse auf die Fragmentierung einiger cis‐trans‐isomerer Bicyclo(m.n. O)alkane
Authors: Herzschuh R. , Mann G.
Published: December 2004

Analysis of Hydrocarbons by Means of Mass Spectrometry. VIII. The Fragmentation of Cis‐Trans Isomeric Bicyclo (m.n. O)alkanes

The mass spectra of the cis‐trans isomeric bicyclo(m.n. O)alkanes are discussed. The molecular ion intensities and the ring strain energies of the bicycloalkanes correlate.
13C‐NMR‐Untersuchung zur π‐Elektronenverteilung in Enaminothioketonen
Authors: Kleinpeter E. , Pulst M.
Published: December 2004

13C‐N.M.R.‐Study of π‐Electron Distribution in Enaminothioketones

The13C‐n.m.r. spectra of a series enaminothioketones SC(R1) C(R2)CHNR3R4have been studied and assigned. HMO — calculations of these compounds — pointing out the π‐electron distribution — are discussed and compared with the13C‐chemical shifts. The investigated enaminothioketones are regarded as compounds with polymethine character and compared with the O — analogous merocyanines.
Azomethinimine. I. Zur Photoreversibilität des Systems Azomethinimin/Diaziridin, untersucht an Pyrazolidon‐Azomethiniminen
Authors: Tomaschewski G. , Geissler G. , Schauer G.
Published: December 2004

Die seit langem bekannten Pyrazolidon‐Azomethinimine 1 sind als carbonylstabilisierte 1,3‐Dipole aufzufassen und lassen sich relativ leicht synthetisieren [1, 2]. Später wurde erkannt, daß diese Verbindungen beim Belichten aus der 1,3‐Dipolform 1 in die bicyclische Diaziridinform 2 übergehen und daß diese Reaktion thermisch reversibel ist [3]. Uns interessierte die Frage, ob die Diaziridine 2 auch photochemisch wieder in die Dipolform überführbar sind.
Zur Stereochemie der Ringöffnung von trans‐1,2‐Diphenylcyclopropanen mit Quecksilber(II)salzen
Authors: Bandaev S. G. , Šabarov Yu. S. , Hantschmann A. , Weissenfels M.
Published: December 2004

Stereochemistry of Ring Opening of trans‐1,2‐Diphenylcyclopropanes by Mercury(II) salts

Reaction of trans‐1,2‐diphenylcyclopropanes 1 and 2 with mercuric salts yields diastereomeric 1,2‐diphenylpropanole derivatives. The ratio of erythro and threo diastereomers depends on the nature of substituents and solvent properties.

A mechanism is proposed to explain the different product ratios.
Benzophenon‐photoinduzierte Oxydationen von Benzylarylethern und aromatischen Lösungsmitteln
Authors: Baumann H. , Timpe H.‐J.
Published: December 2004

Benzophenone Photoinduced Oxidation of Benzyl Aryl Ether and Aromatic Solvents

α‐Ether radicals formed in the photoreaction of benzophenone with benzyl phenyl ether were oxidized in benzene solution to phenol, benzaldehyde and phenylbenzoate. A mechanism including an instable intermediate α‐ether hydroperoxide is discussed with the help of kinetic and CIDNP results. The quantum yields of the oxygen consumption show a linear dependence on the ether concentration. They are much higher in the pure solvent benzene than expected from the quenching and deactivation processes. This agrees with the existence of a biradicalic adduct of triplet benzophenone with aromatic solvents and shows that these solvents are far from being inert under these conditions.
Chemistry and application of organic isocyanates. I. Application of tolylene‐2,4‐diisocyanate for the Syntheses of New Surface‐Active Urethanes of Sucrose and Glucose
Authors: Lesiak T. , Iwaszkiewicz‐Nowak J.
Published: December 2004

Chemie und Anwendung von organischen Isocyanaten. I. Verwendung von Toluylen‐2,4‐diisocyanat für die Darstellung von neuen grenzflächenaktiven Saccharose und Glucoseurethanen

Die Synthese von 3‐Isocyanato‐4‐methyl‐phenylcarbaminsäure‐n‐hexyl‐, n‐heptyl‐, n‐octyl‐, n‐nonyl‐, n‐decyl‐, n‐dodecyl‐, α‐terpinyl‐, bornyl‐ und linalyl‐estern 1–9 wird beschrieben.

Bei der Umsetzung von 1–9 mit Glucose bzw. Sucrose entstehen die neuen, grenzflächenaktiven Saccharose‐ und Glucoseurethane 10–21 (Isomerengemische). Oberflächenspannungen wäßriger Lösungen dieser Verbindungen in Abhängigkeit von der Konzentration werden mit jenen von Natriumdodecylsulfat verglichen.
Partialsynthesen von Cardenoliden und Cardenolid‐Analogen. I. α,β‐ und β,γ‐ungesättigte Lactonring‐methylierte Cardenolide
Authors: Lindig Claus , Repke Kurt
Published: December 2004

Partial Syntheses of Cardenolides and Cardenolide Analogues. I. α,β‐ and β,γ‐Unsaturated Lactone Ring‐Methylated Cardenolides

Base‐catalyzed methylation of digitoxigenin 1a with methyl iodide and sodium hydride in DMF leads to the α,β‐unsaturated cardenolides 2–5 and, after rearrangement of the CC‐double bond, to the β,γ‐unsaturated cardenolides 6 and 7. Opening of the lactone ring results in the formation of 8. Allylic oxidation of 4b affords the 14,21‐epoxide 10. Only the 22‐methyl derivative 4a and its 3‐O‐tridigitoxoside 4d show strong biological effectivity, whereas methylation at 21R‐ or 21S‐position results in considerable loss in activity.
Dreikomponentenreaktionen. XII. Zur Alkoxychlorierung von 3‐Chlorpropen und 3‐Methoxypropen
Authors: Beger J. , Schiefer H.
Published: December 2004

Three Component Reactions. XII. Alkoxychlorination of 3‐Chloropropene and 3‐Methoxypropene

By capillar GLC and 13C‐n.m.r. spectroscopy was demonstrated, that — in contrast to the communications of other authors — both expected isomeric alkoxychlorination products are formed in the chlorination of 3‐chloropropene in presence of several alkanols. Isomers with anti‐Markovnikov orientation dominated in all pairs of isomers which we have identified. Analogous product relations were found in the chlorination as well as in the methoxychlorination of 3‐methoxypropene.
Vergleich der thermischen, photochemischen und massenspektrometrischen Fragmentierung von Schwefelheterocyclen mit cis‐Dithioethylenstruktur
Authors: Fanghänel E. , Poleschner H.
Published: December 2004

Comparison of the Thermal, Photochemical and Mass Spectrometric Fragmentation of Sulphur Heterocycles with cis‐Dithioethene‐Structure

The mass spectrometric primary fragmentation of 3‐methylthio‐1,4,2‐dithiazines 1, 1,4‐dithiins 2, 2,3‐dihydro‐1,4‐dithiin‐2‐ones 4, 1,3‐dithiole‐2‐ones 5, 2‐imino‐1,3‐dithioles 6 and 1,3‐dithiole‐2‐thiones 7 is compared with their thermolytical and photochemical reaction. In the mass spectra an intense peak of the dithiete radical ion is observed, if in the compounds an energetically favourable neutral molecule is preformed: in 1 methyl rhodanide, in 3 ethene, in 4 ketene, in 5 carbon monoxide and in 6 hydrogen cyanide. The substances 1, 3–6 – with the restriction by 3 – yield photochemically the dithiete, too. The photolysis of dithiazines 1 is wave length dependent. Mass spectrometrically, thermally and photochemically the dithiins 2 form thiophenes. The dithiolethiones 7 decompose mass spectrometrically and thermally into carbon disulfide, sulfur and ethynes, but photochemically they form tetrathiafulvalenes. The fragmentation of the compounds 1–6 is analogous in mass spectrometry and photolysis; 2, 3, 5 and with reservation 1 show similar mass spectrometric, thermal and photochemical reactivity. Possible reasons for these analogies are discussed. The dithietes, generated by photolysis of the compounds 1, 4, 5 or 6 react with iron penta‐, nickel tetra‐, molybdenum hexa‐ and tungsten hexacarbonyl in preparative scale to the corresponding dithiolene complexes.