bluuebunny/crossref_metadata_2025 huggingface dataset:
Partialsynthesen von Cardenoliden und Cardenolid‐Analogen. III. Synthese von Cardenolid‐analogen β‐Steroidyl‐crotonsäuremethylestern
Authors: Theil Fritz , Lindig Claus , Repke Kurt
Published: December 2004

Partial Syntheses of Cardenolides and Cardenolide Analogues. III. Synthesis of Cardenolide‐Analogous Methyl β‐Steroidyl‐crotonates

Starting with 14‐hydroxy‐5β, 14β‐pregnan‐3β‐yl‐acetate (2) the synthesis of the cardenolide analogues methyl 3β‐acetoxy‐14, 15β‐epoxy‐24‐nor‐5β, 14β‐chol‐20(22)‐en‐23‐oate (7) via Reformatskij synthesis and methyl 3β, 14‐dihydroxy‐5β, 14β‐chol‐20(22)‐en‐23‐oate (11) via addition of lithium ethoxyacetylide to 2 are described.

The activity of 11 in the ATPase‐test is about the same as that of digitoxigenin.
Substituierte 4‐Amino‐thieno[2,3‐c]isothiazole und 4‐Amino‐thieno[3,2‐d]isothiazole
Authors: Gewald K. , Radke W. , Hain U.
Published: December 2004

Substituted 4‐Amino‐thieno[2,3‐c]isothiazoles and 4‐Amino‐thieno[3,2‐d]isothiazoles

The alkylation of disodium‐(4‐cyanisothiazole‐3,5)‐dithiolate 1 with α‐chloro carbonyl compounds followed by THORPE‐ZIEGLER‐cyclization yields the substituted 4‐amino‐thieno[3,2‐d]isothiazoles 3, which can be converted into the thieno‐isothiazolo‐1,4‐thiazepine derivatives 4, 5. The successive alkylation of 1 with dimethylsulfate and α‐chloro carbonyl compounds yields the 5‐methylthio‐isothiazole‐4‐carbonitriles 11 which are cyclized to form the substituted 4‐amino‐3‐methylthio‐thieno[3,2‐d]isothiazoles 13. The inverse alkylation procedure leads to the isomeric 4‐amino‐3‐methylthio‐thieno[2,3‐c]isothiazoles 20. Successive alkylation of the 3‐hydroxy‐5‐mercapto‐4‐cyanoisothiazoles 14 with α‐chloro carbonyl compounds and diazomethane followed by cyclization yields the 4‐amino‐3‐methoxy‐thieno[3,2‐d]isothiazoles 17. From 13 and 20 the isothiazole‐thieno‐pyrimidines 21, 22 and the isothiazolo‐thieno‐oxazinone 25 are synthesized.
NMR‐Spektroskopische Untersuchungen an Push‐pull‐Butadienen
Authors: Michalik M. , Peseke K. , Radeglia R.
Published: December 2004

N.M.R. Spectroscopic Investigations on Push‐pull Butadienes

1H‐ and 13C‐n.m.r. spectroscopic investigations show the preference of s‐trans configuration and the push‐pull character of the investigated butadienes 1 and 2.
Zur Bromierung des Cyclohexanon‐2‐carbonsäureamids
Authors: Bischoff Christian , Schröder Edith
Published: December 2004

The Bromination of Cyclohexanone‐2‐carboxamide

Cyclohexanone‐2‐carboxamide with bromine forms 6‐bromo‐cyclohexanone‐2‐carboxamide (2) or 2‐bromo‐cyclohexanone‐2‐carboxamide (3). Via Faworski‐rearrangement the reaction of 2 and ammonia or amines gives trans‐cyclopentanedicarboxamides (5a–f). 3 and thiourea form the aminothiazole derivative 6. Pyridinium salt 7 is formed by reaction of 2 and pyridine. 7 and phenylhydrazine form the phenyl‐indazolonoyl‐hydrazine 8. 1 and sodiumhypochlorite yield 2‐hydroxy‐cyclohexanone‐2‐carboxamide (9).
Massenspektroskopie von Naturstoffen. XIII. Massenspektroskopische Untersuchungen von A‐nor‐Allobetulanen
Authors: Schmidt J. , Huneck S.
Published: December 2004

Mass Spectroscopy of Natural Products. XIII. Mass Spectroscopic Investigations of A‐nor‐Allobetulanes

The mass spectroscopic fragmentation behaviour of A‐nor‐allobetulanes with several substituents at C‐2 is discussed. The skeleton fragmentation is comparable to that of C‐3‐substituted allobetulanes. The nature of the substituent at C‐2 influences both the abundance of typical skeleton fragments and the formation of specific ions.
Ein neuer synthetischer Zugang zu Ergot‐Peptidalkaloiden des N‐(d‐Lysergyl‐aminoacyl)‐lactam Types
Authors: Losse G. , Wehrstedt Kl.‐D.
Published: December 2004

A General Synthetic Pathway to Ergot Peptide Alkaloides of the N‐(d‐Lysergyl‐aminoacyl)‐lactam Type

The structure and configuration of the novel ergot alkaloid from Claviceps purpurea N‐(d‐Lysergyl‐valyl)‐phenylalanyl‐D‐prolin‐lactam (2) has been proved by synthesis. In addition, a general synthetic pathway to N‐(d‐Lysergyl‐aminoacyl)‐lactams of this type is opened, which are possible key intermediates in the biogenesis of ergot peptide alkaloides.
Elektrosynthese cyclischer Hydroxamsäuren mit anschließender analoger Bamberger‐Umlagerung
Authors: Matschiner H. , Tanneberg H. , Maschmeier C.‐P.
Published: December 2004

The Electrochemical Synthesis of Cyclic Hydroxamic Acids Followed by Bamberger‐Rearrangement

The electrochemical reduction of 2‐(o‐nitro‐phenylthio)acetic acid 1a results in the expected cyclic hydroxamic acid 3a and a rearranged product 4a by consuming 4 electrons. The analogous reduction of 2‐(o‐nitro‐phenoxy)acetic acid 1b leads only to a rearranged product 4b. This fact has been explained by the Bamberger‐rearrangement of the hydroxylamine intermediate 2a, b. Now the rearrangement of the expected products was shown as a new aspect to explain the formation of the products.
Photooxidation von Arylazonaphtholen mit Singulett‐Sauerstoff
Authors: Becker H. G. O. , Franze J.
Published: December 2004

Photooxidation of Arylazo‐Naphtholes with Singlet Oxygen

The reaction of p‐substituted 4‐arylazo‐1‐naphtholes 1 and 1‐arylazo‐2‐naptholes 5 with singlet oxygen (produced by methylene blue‐sensitized photolysis) has been studied spectroscopically in methanol as a solvent. The rate constants of dye bleaching are the same, irrespective whether the extinctions of the azo or the hydrazone forms of the tautomeric systems are measured. Both reaction series 1 and 5 afford linear Hammett plots, which is discussed in the light of the azohydrazone equilibrium of the dyes and an „ene”︁ mechanism of the reaction with singlet oxygen. It could be shown by short‐time spectroscopy that the azo‐hydrazone isomerization proceeds much faster than the attack of singlet oxygen on the hydrazone form, which explains all observed facts.
Synthese von Heterocyclen durch CC‐Knüpfung. V. Eine neue Pyridonsynthese
Authors: Schmitz Ernst , Schramm Siegfried
Published: December 2004

Synthesis of Heterocyclic Compounds by CC‐bond Closure. V. A Novel Pyridone Synthesis

Under the action of alkali two moles of N‐primary alkyl cyanoacetamides 5 condense to form 1‐alkyl‐5‐alkylaminocarbonyl‐4,6‐diamino‐pyridone‐2 (6)
Chemische Synthese des Dodecanucleotids dCACAAGCTTGTG
Authors: Weiss R. , Birch‐Hirschfeld E.
Published: December 2004

Chemical Synthesis of the Dodeecanuceleotide. dCACAAGCTTGTG

For studies of some sequence dependent structural factors the self‐complementary dodecanucleotide dCACAAGCTTGTG was required. Its chemical synthesis is reported according to the diester approach starting with the monomers dC, dpA, dpG, dpC and dpT.
Lichtinitiierte Polymer‐ und Polymerisationsreaktionen. III. Photoinduzierte Zersetzung von Aryldiazoniumsalzen durch Benzoinderivate
Authors: Baumann H. , Müller U. , Pfeifer D. , Timpe H.‐J.
Published: December 2004

Light Induced Polymer and Polymerization Reactions. III. Photoinduced Decomposition of Arene Diazonium Salts by Benzoin Derivatives

The combination benzoin derivate/arene diazonium salt is suitable as a bivalent photoinitiator system for radicalic and cationic photopolymerization. By means of product analysis, quantum yield measurements and photo‐CIDNP‐studies a mechanism was proposed including the electron transfer from α‐substituted benzyl radicals formed by benzoin derivate photolysis to arene diazonium salts. The quantum yields for diazonium salt decomposition in acetonitril were about 0.65. They show only a small dependence on substituents of diazonium salt but are strong influenced by the solvent. In methanol or dioxane quantum yields were found from 11 to 460. 13C‐photo‐CIDNP‐measurements agree with a mechanism of benzoin ether photolysis on the triplet state.
Heterocyclisch substituierte Cumarine aus β‐Chloropropeniminiumsalzen
Authors: Czerney Peter , Hartmann Horst
Published: December 2004

Heterocyclic Substituted Coumarines from β‐Chloropropeniminium Salts

3‐Chloro‐3‐coumar‐3′‐yl‐propeniminium salts 7 or the derived aldehydes 10 are versatile synthons for the preparation of heterocyclic substituted coumarines 5. The transformation of the starting materials into the coumarines 5 can be carry out in more steps or in one step directly.
Theoretical description of solvent effects. V. The medium influence on the lactim‐lactam tautomerism of hydroxyazines
Authors: Krebs C. , Förster W. , Weiss C. , Hofmann H.‐J.
Published: December 2004

Theoretische Beschreibung von Lösungsmitteleffekten. V. Der Mediumeinfluß auf die Lactim‐Lactam‐Tautomerie von Hydroxyazinen

Der Lösungsmitteleffekt auf die Tautomeriegleichgewichte der Titelverbindungen wird mit Hilfe klassischer und quantenchemischer Versionen der Solvatonen‐ und der Reaktionsfeldtheorie berechnet. In Übereinstimmung mit dem Experiment ergeben alle getesteten Verfahren eine Gleichgewichtsverschiebung zugunsten der Lactamform. Zur quantitativen Beschreibung dieses Effektes ist jedoch das Reaktionsfeldmodell besser geeignet.
Desaktivierung angeregter Singulettzustände von N‐Arylurethanen durch intra‐ und intermolekulare Energieübertragung auf Salicylsäureester und ‐amide
Authors: Stumpe J. , Schwetlick K.
Published: December 2004

Quenching of Excited Singlet States of N‐Arylurethanes by Intra‐ and Intermolecular Resonance Energy Transfer to Salicylic Acid Esters and Amides

Fluorescence and photo‐Fries reactions of N‐arylurethanes are quenched by energy transfer to salicylic acid esters and amides. Quenching of photo reaction and fluorescence obeys the Stern‐Volmer equation and is accompanied by sensitization of salicylic acid ester fluorescence.

The rate constants of energy transfer are greater than the diffusion rate constants and show that resonance energy transfer occurs.

The influence of solvent viscosity, donor lifetime, and spectral overlap is discussed. The rate constants of energy transfer are slightly decreased by increasing the solvent viscosity.

The results are in good agreement with the treatment of POVINELLI.
Flüssigphasenoxydation von Cyclohexen in Gegenwart von Kombinationen von Verbindungen verschiedener Metalle
Authors: Boeden H.‐F. , Dahlmann J. , Hamann H.‐J. , Höft E.
Published: December 2004

The Liquid Phase Oxidation of Cyclohexene in Presence of Combinations of Compounds of Different Metals

The oxidation of cyclohexene (1) with molecular oxygen in chlorobenzene solution at 80°C has been studied using cobalt, manganese and copper compounds, respectively in combination with molybdenum complexes. The selectivity has been determined of cyclohex‐2‐en‐1‐hydroperoxide (2), epoxycyclohexane (3), cyclohex‐2‐en‐1‐ol (4), cyclohex‐2‐en‐1‐one (5), 2,3‐epoxy‐cyclohexane‐1‐ol (6) and cyclohexane‐1,2‐diol (7), formed from reacted 1. Investigation of the consecutive reactions showed that 3 and especially 4 can react in different ways and moreover 4 inhibits the oxidation of 1. From these results conclusions were drawn on the mechanism of oxidation of 1.
α‐Substituierte Phosphonate. 40. 1‐Trimethylammonium‐1‐diethylphosphono‐1‐cyanomethylid, ein stabiles N‐Ylid
Authors: Costisella B. , Gross H.
Published: December 2004

α‐Substituted Phosphonates. 40. 1‐Trimethylammonium‐1‐diethylphosphono‐1‐cyanomethylid, a Stable N‐Ylid

Diethyl‐1‐dimethylamino‐1‐cyanomethanephosphonate 4 can be alkylated on nitrogen to the quarternary ammoniumsalts 5, which by C‐deprotonation gives the stable N‐ylid 8. The N‐ylid 8 behaves inert against carbonyl compounds and acylating agents, but can be C‐alkylated and — involving an ester‐dealkylation — C‐chlorinated.
Synthese von Heterocyclen durch CC‐Knüpfung. IV. Heterocyclensynthesen durch intramolekulare Dien‐Reaktion
Authors: Schmitz Ernst , Heuck Uwe , Preuschhof Helmut , Gründemann Egon
Published: December 2004

Synthesis of Heterocyclic Compounds by CC‐bond Closure. IV. Synthesis of Heterocyclic Compounds by Intramolecular Dienreaction

N‐2‐Cyclohexenyl‐N‐isopropylcinnamamide 8 cyclizes at 230°C to give the decahydronaphthindolone 9. N‐Alkyl‐N‐allylcinnamamides 10 analogously form 1 H‐hexahydrobenzisoindolones 11. N‐Alkyl‐N‐allylsorbamides 14 cyclize at 150°C to 1 H‐hexahydroisoindolones 15. 15b yields the cyclic enamide 16 by alkali catalyzed shift of the double bond. Tricyclic lactames 19 and 20 are formed by thermal isomerization of N‐cycloalkenylsorbamides 18a and 18b, respectively.
NMR‐Untersuchungen an Dicyclopentadien‐Derivaten. VII. Zur Abhängigkeit des γ‐gauche Effektes von der sterischen Kompression eng benachbarter Protonen bei exo/endo‐Isomerieumkehr
Authors: Kleinpeter E. , Kühn H. , Mühlstädt M. , Jancke H. , Zeigan D.
Published: December 2004

N.M.R. Investigations of Dicyclopentadiene Derivatives. VII. Dependence of the γ‐Gauche Effect on the Steric Compression of Closely Neighbouring Protons during the Reversal of Exo/Endo‐Isomerism

The 13C‐chemical shifts of the carbon atoms C1, C6, C7, C8 and C10 of different substituted exo/endo‐isomeric dicyclopentadiene derivatives are highly depending on the configuration of these compounds. The observed shift effects are discussed within the concept of the steric γ‐gauche effect and are not only explained by nonbonding interactions of steric closely neighbouring protons.
Untersuchungen zum Verlauf der Cyclisierung von Alkylmalonsäure‐ und β‐Amino‐crotonsäureestern zu alkylierten Hydroxypyridincarbonsäureestern
Authors: Schrötter E. , Niedrich H. , Schick H.
Published: December 2004

Investigations on the Cyclization of Alkylmalonic Acid Esters with β‐Aminocrotonic Acid Esters to Alkylated Hydroxypyridine Carboxylic Acid Esters

The cyclization of substituted malonic esters with β‐aminocrotonic acid alkyl esters yields 2,4‐ or 4,6‐dihydroxy‐3‐pyridinecarboxylic acid esters, respectively, in dependence on the reaction conditions and the nature of the substituent in the malonic esters. In the presence of alcoholate malonic acid alkyl esters and alkylmalonic acid alkyl esters form 2,4‐dihydroxy‐3‐pyridinecarboxylic acid esters. Under the same conditions nitromalonic acid alkyl esters lead to 4,6‐dihydroxy‐3‐pyridinecarboxylic acid esters, which also arise in the thermal cyclization of malonic acid 2,4,6‐trichlorophenyl ester. The structure of the reaction products is determined by the relative nucleophilicity of the cyclization components.
Darstellung und Reaktionen von β‐Oxosulfenylchloriden. II. Direkte Chlorsulfanylierung von disubstituierten Acetaldehyden mit Schwefeldichlorid
Authors: Mühlstädt Manfred , Meinhold Hansjürgen , Martinetz Dieter , Neumann Eberhard
Published: December 2004

Preparation and Reactions of β‐Oxosulfenyl Chlorides. II. Direct Chlorosulfenylation of Disubstituted Acetaldehydes by Sulfur Dichloride

The reaction of dialkylacetaldehydes (1a, b) with sulfur dichloride yields the corresponding β‐oxosulfenylchlorides (2a, b). Examples for addition‐ and substitution‐reactions of 2a, b are described.
Nucleophile Substitutionen an funktionellen Kohlensäurederivaten. XVI. Kinetik und Mechanismus der Hydrolyse von Kohlensäure‐ N,N,N′‐triphenylchloramidin
Authors: Bacaloglu R. , Bacaloglu I. , Chicu A.
Published: December 2004

Nucleophilic Substitution to Carbonic Acid Derivatives. XVI. Kinetics and Mechanism of N,N,N′‐Triphenylchloroformamidin Hydrolysis

First order rate constants of N,N,N′‐triphenylchloroformic amidine hydrolysis in dioxane‐water have been determined by u.v.‐spectroscopy. The effects of water concentration, addition of KClO4, LiCl, HgCl2, and AgNO3 or nucleophilic agents (piperidine) as well as isotopic effects have been investigated. Activation entropy and enthalpy have been determined. According to the data obtained the reaction takes place in two steps – chlorionization and reaction of the formed cation with the nucleophilic agent. Both steps have rates of the same order of magnitude, but can become slow steps in specific conditions.
The Complexes of Dipicolinic Acid and Related Compounds in oxidation of organic substrates
Authors: Achremowicz Lucjan , Młochowski Jacek , Mora Czesław , Skaržewski Jacek
Published: December 2004

Komplexe der Dipicolinsäure und verwandter Verbindungen zur Oxidation organischer Substrate

Die Oxidation von methylierten Hydrochinonen zu Chinonen und von α,β‐ungesättigten Alkoholen zu Aldehyden in Gegenwart verschiedener Oxidationsmittel wurde untersucht.

Günstige Ergebnisse wurden bei der Anwendung des MnO2‐Dipikolinsäure‐Systems für d'e Oxidation von Allyl‐ und Benzylalkoholen und des AgO‐Dipikolinsäure‐Systems für die oxidative Demethylierung von methylierten Hydrochinonen erreicht.

Der Einfluß der Struktur von 4‐substituierten Dipicolinsäuren auf die katalytischen Eigenschaften wurde untersucht.
Untersuchungen zum UV/Vis‐Spektralverhalten von Azofarbstoffen. VI. Zum Einfluß von Substituenten auf die Farbe von Derivaten des 1‐Phenylazo‐2‐naphthols
Authors: Mustroph H. , Bartel R.
Published: December 2004

Studies on UV/Vis Absorption Spectra of Azo Dyes. VI. The Effect of Substituents on the Color of Derivatives of 1‐Phenylazo‐2‐naphthols

The absorption spectrum of 1‐(4′‐diethylaminophenylazo)‐2‐naphthol has been examined, and it has been found that the absorption band at 510 nm corresponds to the azo form and the shoulder at 610 nm corresponds to the hydrazone tautomeric form. Substituents in 3‐position of 2‐naphthol which have a free proton (e.g. OH, COOH, CONHR) stabilize the hydrazone tautomeric form by an intramolecular hydrogen bonding between substituent and hydrazone oxygen. Substituents which have not a free proton (e.g. OCH3, COOCH3, CONR1R2) have little influence on the absorption spectrum.

The relative intensities of the two bands of the tautomeric forms are dependent on:

— the electron attracting or electron releasing effect of the substituent R in CONHR

— the hydrogen bonding acidity of the substituents in 2′‐position if R in CONHR is a phenylring

— the hydrogen bonding acidity of the solvent.

The effect of substituents in the phenylazo subsystem is also discussed.
Elektrochemische Darstellung von organischen Diseleniden
Authors: Jeroschewski P. , Ruth W. , Strübing B. , Berge H.
Published: December 2004

Electrochemical Preparation of Organic Diselenides

By the method of electrosynthesis a number of organic diselenides can be prepared simply and without danger. The cathodic polarisation of a special selenium electrode in aprotic solutions gives rise to polyselenideanions, which react with electrophilic compounds to the corresponding diselenides of the general formula RSeSeR (2a–e) with R = benzyl, 2‐nitrophenyl, cyclohexyl, isopropyl, 4‐cyanophenyl.
d‐NMR‐Untersuchungen der behinderten Rotation am NC(X)‐Bindungsfragment. XIV. 13C‐NMR‐Spektren von β‐Anilinovinyl‐phenyl‐thioketonen
Authors: Kleinpeter E. , Pulst M. , Pihlaja K.
Published: December 2004

d‐N.M.R. Investigations of the Restricted Rotation at the NC(X) Bonding Fragment. XIV. 13C‐N.M.R.‐Spectra of β‐Anilinovinyl‐phenyl‐thioketones

N‐phenyl‐substituted β‐anilinovinyl‐phenyl‐thioketones (1, 2) are investigated for restricted rotations about partial double bonds and preferential conformers by 1H‐ and 13C‐n.m.r. spectroscopy. Substituent dependent 13C‐chemical shift variations and the strength control of the intramolecular hydrogen bridge are discussed.
Exo‐ and endohormones. V. Syntheses of the Sex Pheromone of the European pine shoot moth (rhyacionia buoliana). The Grignard route
Authors: Popovici N. , Botar A. A. , Barabás A. , Oprean I. , Hodosan F.
Published: December 2004

Exo‐ and Endohormones. V. Synthesen des Sexualpheromons des Kiefernknospentriebwicklers (Rhyacionia buoliana) durch Grignard‐Reaktionen

Grignard‐Kopplungen zwischen zwei entsprechenden Synthonen führen zum (E)‐9‐Dodecen‐1‐ylacetat (1), dem Sexuallockstoff des Kiefernknospentriebwicklers (Rhyacionioa buoliana). Als solche Synthon‐Paare wurden 1‐Brom‐(E)‐2‐penten (2) und 7‐Bromheptyltetrahydropyranylether (3) bzw. (E)‐3‐Hexen‐1‐yltosylat (4) und 6‐Bromhexyltrimethylsilylether (5) eingesetzt. Das Endprodukt (1) und die wichtigsten Zwischenprodukte wurden durch ihre 1H‐ und 13C‐NMR‐Spektren charakterisiert. Durch die zweite Synthese wurden 100% Regio‐ und 99% Stereoselektivität erreicht.
Zur Kinetik der Halcon‐Reaktion
Authors: Megdiche R. , Schnurpfeil D.
Published: December 2004

The Kinetics of the Halcon Reaction

We have investigated the influence of all types of reaction products on the rate of the Halcon reaction. The experiments show that the retarding effect of epoxide is higher than that of the alcohol. Furthermore we have found that the consecutive products of the epoxide retard the Halcon reaction more than the primary reaction products. The reaction rate can be described by an equation of the Michaelis‐Menten‐type. We determined the initial reaction rate in dependence on the starting concentration on the reaction products.
Zur Nitrierung von Ethylenoxid
Authors: Slavtscheva Ju. , Minkov D. , Kolev N.
Published: December 2004

About the Nitration of Ethylene Oxide

Nitration of ethylene oxide with pure nitric acid of different concentrations as well as in presence of sulphuric acid was carried out.

The products, ethyleneglycol dinitrate 1, diethylenglycol dinitrate 2, triethyleneglycol dinitrate 3, tetraethylenglycol dinitrate 4, ethyleneglycol mononitrate 5, diethyleneglycol mononitrate 6, and 2, 2′‐dinitratediethylsulphate 7 were structurally determined by i. r.‐ and 1H‐n. m. r.‐spectroscopy.
Zur Umsetzung von o‐Lithio‐lithiumphenolat und o‐Lithio‐N‐methyl‐lithiumanilid mit Halogeniden des Phosphors, Arsens und Siliziums
Authors: Heinicke J. , Tzschach A.
Published: December 2004

Reactions of o‐Lithio‐lithiumphenolate and o‐Lithio‐N‐methyl‐lithiumanilide with Halides of Phosphorus, Arsenic and Silicon

The title compounds and chlorides of the type CIERn (E = P, As, Si) react smoothly in a molecular ratio of 1:2 to give the corresponding disubstituted phenole and N‐methylaniline derivatives, respectively. Attempts with an 1:1 ratio show different results depending on the reactivity of the EO or EN species towards organolithium reagents.
Theoretische Untersuchungen zum elektrophilen Angriff. IX. Intramolekulare H‐Verschiebungen in den protonierten orthodisubstituierten Aromaten o‐Xylen und 1, 2‐Difluorbenzen
Authors: Heidrich D. , Weiss C. , Illek B.
Published: December 2004

Theoretical Studies on the Electrophilic Attack. IX. Intramolecular H‐Shifts in the ortho‐Disubstituted Aromatic Compounds o‐Xylene and 1, 2‐Difluorobenzene

A potential energy characterization of the proton shifts in the above cited 1, 2‐disubstituted aromatic compounds and their dependence on solvent influence are studied by means of theoretical methods. The results complete in many points our knowledge of experimental data in solution estimated from n. m. r. spectroscopic investigations.
Zum Einfluß stereochemisch bedingter Energieunterschiede auf die Ionisation und Fragmentierung von Tricyclo[5.2.1.02, 6] decanen, ‐decenen und ‐decadienen
Authors: Herzschuh R. , Kühn H. , Mühlstädt M.
Published: December 2004

The Influence of the Strain Energies on the Ionization and the Fragmentation of Tricyclo [5.2.1.02, 6]decanes, ‐decenes and ‐decadienes

The mass spectra of the title compounds are discussed. The inverse relationship of the abundance of the molecular ions with the calculated strain energies has been found to occur in the stereoisomers. The main fragmentation of the alkenes is the Retro‐Diels‐Alder cleavage. The stereochemical effects influence also the ionization and appearance energy.
Hammett‐Beziehungen zwischen 1H‐NMR‐ bzw. 31P‐NMR‐chemischen Verschiebungen und Substituenten‐konstanten in ω‐Diphenylphosphinyl‐und ω‐Diphenylthiophosphinyl‐trans‐styrenen
Authors: Gloyna D. , Köppel H. , Schleinitz K.‐D. , Berndt K.‐G. , Radeglia R.
Published: December 2004

Hammett Relationships between 1H‐NMR and 31P‐NMR Chemical Shifts, Respectively, and Substituent Constants in ω‐Diphenylphosphinyl and ω‐Diphenylthiophosphinyl trans‐Styrenes

A well linear correlation between the chemical shifts of the ethylenic protons HB and the 31P nuclei, respectively, and the Hammett constants σp of substituents R in 4‐position for diphenylphosphinyl trans‐styrenes 1 and the analogous diphenylthiophosphinyl trans‐styrenes 2 has been found. A similar relationship for the proton HA has been observed in the case of 1 only, but the substituent‐induced shifts are not so sensitive. Donor substituents R in 1 and 2 effect an increase in the shielding of HB and a deshielding of the P atom being connected with shifts of the i. r. PO absorption bands in 1 in the direction of lower wavenumbers. A mesomeric interaction between R and PY substituents (Y = O, S) is concluded to produce polymethin‐like π‐electron density distribution.
Zur Pyrolyse von 1‐14C‐Pent‐1‐en
Authors: Kopinke F.‐D. , Bach G. , Ondruschka B. , Zimmermann G.
Published: December 2004

On the Pyrolysis of 1‐14C‐Pent‐1‐ene

In the thermal decomposition of 1‐14C‐pent‐1‐ene at 550 to 650°C a mixture of saturated and olefinic hydrocarbons ⩽ C6 is formed. The reaction products were analyzed by gaschromatography, the distribution of radioactivity in the main products by radio gaschromatography.

The results are discussed on the basis of a conventional radical reaction scheme including 1.4‐ and 1.5‐H‐shifts in intermediate alkyl and alkenyl radicals. The distribution of pyrolysis products and of their radioactivity allows a semiquantitative description of the complex decomposition of n‐pent‐1‐en.
Synthese und Reaktionsverhalten von 2‐Aryl‐3‐chlormaleinimiden
Authors: Augustin M. , Faust J. , Köhler M.
Published: December 2004

Synthesis and Reaction Behaviour of 2‐Aryl‐3‐chloro‐maleimides

2‐Aryl‐3‐chloro‐maleimides 2 are prepared by the chlorination of aryl‐maleicanhydrides and aminolysis of the resulting 1‐aryl‐2‐chloro‐maleicanhydrides 1. The imide 2a is reacted with N, S, O and Cnucleophiles and inorganic salts to give 2, 3‐disubstituted maleimides 3–6, 9, 10, 12, condensed heterocycles 7 and maleimide dimeres 8, 13, 14.
Elektrochemische Adamantylierung von Styrylpyridinen
Authors: Hess U. , Huhn D.
Published: December 2004

Electrochemical Adamantylation of Styrylpyridines

The reaction between electrochemically generated anion radicals of the 4‐(4‐styryl)‐pyridines 1–6 and 1‐bromoadamantane gives, in solvents of low proton availability as N, Ndimethylformamide via an electron transfer in solution and formation of 1‐adamantyl‐radicals, monoadamantylated pyrid‐4‐yl‐phenylethanes. The major product results from an anion radical/radicalcoupling in the 2(β)‐ next the 1(α)‐position. A competing pathway of the electrohydroadamantylation is the hydrogeneration of the CHCHdouble bond, whose importance increases with the water content of the solvent. Based on cyclic‐voltammetric evidence and product distribution, the mechanism of the reductive coupling of 1–6 in the presence of 1‐bromoadamantane in discussed in terms of indirect electrolysis.
Nucleophile Substitutionen in der 1, 3, 5‐Triazinreihe. VIII. Zur Hydrolyse des Cyanurchlorids in Dioxan‐Wasser
Authors: Bacaloglu R. , Havlik J.
Published: December 2004

Nucleophilic Substitutions in the 1, 3, 5‐Triazines. VIII. The Hydrolysis of Cyanuric Chloride in Dioxane Water

The kinetics of cyanuric chloride first step hydrolysis in dioxan‐water was conductometrically studied. At small water concentrations the slow stage of hydrolysis at 2,4‐dichloro‐6‐hydroxy‐1,3,5‐triazin consists in the nucleophilic attack ot water molecule to cyanuric cloride. At higher water concentrations the rate of this process exceeds that of the chlorine anion monomolecular elimination which becomes the slow step.
Die Bestimmung der Optischen Reinheit an Zwischenprodukten der Prostaglandinsynthese mit Hilfe der NMR‐Spektroskopie
Authors: Zepter Rudolf , Wentzke Manfred , Schwarz Sigfrid
Published: December 2004

The Determination of Enantiomeric Purity of Intermediates for Prostaglandins by N. M. R. Spectroscopy

Im Rahmen einer Prostaglandinsynthese waren chirale Ringschlüsselprodukte durch mikrobielle Transformation gewonnen worden [1]. Zur vollständigen Charakterisierung dieser Ringschlüssel‐produkte war die Kenntnis ihrer optischen Reinheit unerläßlich. Wir haben für diese Untersuchungen die 1H‐NMR‐Spektroskopie unter Verwendung eines chiralen Verschiebungsreagenzes eingesetzt.
Mehrfunktionelle N‐Tenside. IV. Synthesen hydroxy‐ und chloralkylierter Amine — Struktureinfluß auf die Extraktion von Zinkionen aus salzsauren Lösungen
Authors: Schade W. , Beger J. , Jacobi R. , Neumann R.
Published: December 2004

Polyfunctionalized N‐Tensides. IV. Synthesis of Hydroxy‐ and Chlorine Substituted Alkylamines — Structure Dependence on the Extraction of Zinc Ions from Hydrochloric Acid

A few series of long‐chained amines with or without further functional groups in the shorter alkyl chains were synthesised and checked for their extraction power for zinc ions. The extrability of zinc increase in the order secondary tertiary quarternary amino function, is independent of the length of the longest alkyl chain between ten and sixteen carbon atoms and increase with a given substituent R in the order OH ≃ H < Cl.

In general there are only small differences between most of the checked amines.
Über die Pyrolyse von Pent‐1‐en‐3,3‐d2
Authors: Kopinke F.‐D. , Bach G. , Ondruschka B. , Rennecke D. , Zimmermann G.
Published: December 2004

On the Pyrolysis of Pent‐1‐ene‐3,3‐d2

The distribution of deuterium in the main products of the thermal decomposition of pent‐1‐ene‐3,3‐d2 at 550 to 650°C was studied and interpreted. The results include conclusions on kinetic isotope effects, on relative reactivities of different CH‐bonds, and on the importance of nonterminal radical addition. It is shown that butadiene‐d2 detected in the isotopically labeled butadiene fraction is a reliable target molecule for the homoallylic rearrangement of the pent‐1‐ene‐4‐yl‐3,3‐d2 radical.
Reaction of [Fe(DMF)3Cl2][FeCl4] Complex with Some Phenolic Substrates
Authors: Varma Manju , Varma Rajender S. , Parthasarathy Madhanam R.
Published: December 2004

Reaktion des [Fe(DMF)3Cl2] [FeCl4]‐Komplexes mit einigen Phenol‐Derivaten

Der Anwendungsbereich des [Fe(DMF)3Cl2] [FeCl4]‐Komplexes, der in der biomimetischen Synthese einiger Naturprodukte angewendet wird, wurde weitergehend an Phloroglycinol‐ und Resorcinol‐Systemen untersucht.

Es wurde keine oxidative Dimerisierung beobachtet. Die Chlorierung der Methylengruppe und die Cyclisierung der entsprechend substituierten o‐Hydroxyacetophenone zu den Cumaran‐3‐on‐Derivaten laufen nebeneinander ab.
Elektrochemische Oxydation organischer Verbindungen in Fluorsulfonsäure. IV. Voltammetrische Untersuchungen zur Bildung und zum anodischen Verhalten einiger Benzylkationen und Arenium‐Ionen
Authors: Rudenko A. P. , Sarubin M. Ja. , Pragst F.
Published: December 2004

Electrochemical Oxidation of Organic Compounds in Fluorosulfuric Acid. IV. Voltammetric Investigation of the Formation and of the Anodic Behaviour of Some Benzyl Cations and Arenium Ions

The anodic behavior of a series of benzylic alcohols, ethers or acetates 1–10, benzyl cyanides 11–21 and aromatic hydrocarbons 22–35 is investigated by cyclic voltammetry in fluorosulfuric acid at −76°C. The oxidation of the benzyl cations ArCH+2 formed from a part of the benzylic compounds leads at potentials by 0,7 to 0.8 V more positive than those of the neutral compounds with addition of SO3F− to stable cation radicals ArCH2OSO2F+. In a further oxidation step another CH3‐group is functionalized to CH2OSO2F. The anodic peak potentials of the arenium ions are by about 1.1 V more positive than those of the nonprotonated hydrocarbons. The dissociation equilibrium of ArCH2OSO2F und the protonation equilibrium of the hydrocarbons are discussed in terms of the donor ability of the aromatic compounds at borderline cases.
Reaktionen von Heteroaryliminotriphenylphosphoranen mit Heterokumulenen: Synthese und Cycloadditionen α‐N‐Heteroaryl‐substituierter Carbodiimide
Authors: Bödeker J. , Courault K. , Köckritz A. , Köckritz P.
Published: December 2004

Reactions of Heteroaryliminotriphenylphosphoranes with Heterocumulenes: Synthesis and Cycloaddition Reactions of α‐N‐Heteroaryl‐substituted Carbodiimides

N‐α‐Heteroaryl‐substituted iminotriphenylphosphoranes react with phenylisocyanate, phenylisothiocyanate, and carbon disulfide to symmetrical and unsymmetrical α‐heteroaryl‐carbodiimides. These can not be isolated as monomeres because they behave as 1.3‐diazabutadienes predominantly and form 4+2‐cycloadducts. The monomeric intermediates cyclodimerize to the 1.3.5‐triazines 5 resp. 14 or react by the same scheme both with phenylisocyanate and with phenylisothiocyanate to give the 1.3.5‐triazines 4, resp. 12. In competition with this reaction a 2+2‐cycloaddition takes place, hence there follow numerous by‐products. The structure of 1.3.5‐triazines is determined from hydrolysis to guanidines 6 and on the basis of spectroscopic methods.
Antiviral wirksame Koordinationsverbindungen des Palladiums mit Pyrid‐2‐yl‐aminen
Authors: Heyn B. , Schröer H.‐P.
Published: December 2004

Antiviral Active Complexes of Palladium Chloride with 2‐Pyridine Amines

2‐Pyridine amines (L) form complexes with palladium chloride LPdCl2OH2 and L2PdCl2, respectively. The synthesis and analytical characterisation, ir‐spectra, n.m.r.‐spectra of these complexes with L = 2‐pyridine amine, 4‐methyl‐2‐pyridine amine and 6‐methyl‐2‐pyridine amine and of π‐allyl palladium chloride 4‐methyl‐2‐pyridine amine are described.
Dicyclopentadienoxidation. I, Unkatalysierte Flüssigphasenoxidation von Dicyclopentadien
Authors: Schnurpfeil D.
Published: December 2004

Dicyclopentadiene Oxidation I. Uncatalyzed Liquid‐Phase Oxidation of Dicyclopentadiene

Dicyclopentadiene is oxidized by molecular oxygen to a mixture of the monoepoxides 2 and 3. The identification of the epoxides 2, 3 and 4 was executed with authentic samples prepared by epoxidation with peracetic acid or with tert‐butylhydroperoxide in the presence of MoO2(acac)2

acac — Acetylacetonat

The main product is the substituted norbornene oxide
2
. Allylic oxidation is also observed. Remarkable amounts of hydroperoxides can be determined iodometrically. The formation of allylic oxidation products
7
,
8
,
9
and
10
was proved by GC‐MS‐analysis. It is shown that in the uncatalyzed liquid phase oxidation of dicyclopentadiene no more than 50% of epoxides are formed. The bisepoxide
4
was found in small amounts only at higher conversions of the dicyclopentadiene.
Zum Konformationsverhalten isomerer Phenylpyrimidine — Molekül‐ und Kristallstruktur von 5‐Chlor‐2‐(4‐n‐hexyloxyphenyl)‐pyrimidin
Authors: Rapthel I. , Hartung H. , Richter R. , Jaskólski M.
Published: December 2004

On the Conformational Behaviour of Isomeric Phenyl Pyrimidines — Molecular and Crystal Structure of 5‐Chloro‐2‐(4‐n‐hexyloxyphenyl)‐pyrimidine

The title compound crystallizes in the triclinic space group P1 with a = 979.6(1) pm, b = 1048.8(3) pm, c = 1629.9(1) pm, α = 89.51(1)°, β = 100.62(1)°, γ = 71.50(1)° and four molecules per unit cell. The structure has been solved by direct methods and refined to a final R value of 0.058. The molecules adopt a fully stretched and nearly planar form and show a parallel arrangement in the crystal lattice. The results are discussed in relation to the conformational and mesomorphic behaviour of isomeric substituted phenyl pyrimidines.
Elektrochemische Oxidation organischer Verbindungen in Fluorsulfonsäure. V. Anodisches Verhalten aromatischer Nitroverbindungen, Nitrile, Amine, Acetamide und Oxime
Authors: Rudenko A. P. , Sarubin M. Ja. , Pragst F.
Published: December 2004

Electrochemical Oxidation of Organic Compounds in Fluorosulfuric Acid. V. Anodic Behaviour of Aromatic Nitrocompounds, Nitriles, Amines, Acetamides, and Oximes

The anodic behaviour of a series of methyl substituted nitrobenzenes, benzonitriles, aniline derivatives, acetanilides and acetophenone oximes was investigated by cyclic voltammetry at platinum electrodes in HSO3F at −76°C. With the exception of the parent compounds and partly of the monomethyl derivatives relatively stable cation radicals could be detected. In a second anodic wave in many cases the functionalization of a CH3‐group to CH2‐OSO2F took place. From a comparison of the peak potentials and from the dependence of the voltammetric curves on the scan rate follows that the aniline derivatives are oxidized without deprotonation of the −NH3+ group, whereas for the nitrocompounds, nitriles and acetanilides a deprotonation of the functional group is coupled with the oxidation, and the cation radicals are stable onyl in the deprotonated state. A kinetic study of the subsequent reaction of some nitrocompounds was made and the deviating behavior of some acetanilides was found to be due to the anodic dimerization to benzidine derivatives.
Kinetische Untersuchungen der Reaktionen von Methylradikalen mit Allen
Authors: Scherzer K. , Claus P. , Dabbagh M.
Published: December 2004

Kinetic Studies of the Reactions of Methyl Radicals with Allene

The addition of methyl radicals to allene has been studied in the temperature range 573…595 K. The methyl radicals were produced by thermal decomposition of azomethane. It has been shown that the additions take place with a very high selectivity at the terminal carbon atoms in allene. The rate constant k2 of the addition can be expressed by the following Arrhenius equation:
Theoretische Untersuchungen zum Zerfallsgleichgewicht des Harnstoffs in Gasphase und in wäßriger Lösung
Authors: Schädler H. D. , Schroth W. , Weiss C.
Published: December 2004

Theoretical Investigations on the Decomposition Equilibrium of Urea in Gaseous State and Aqueous Solution

There is empirical evidence that among the two possible decomposition equilibria of urea in the gaseous and aqueous states the desammonation process prevails. In the present work the thermodynamic and kinetic conditions of desammonation and dehydration based on intramolecular mechanisms were examined by means of quantum chemical methods. The application of MNDO method yields correct structural data, dipole moments and ionisation potentials; the solvation is taken into account using NDDO based solvation and reaction field models. Maximum deviations concerning enthalpies of formation in π‐electron rich compounds reach up to 40kJ/mole. A detailed examination of the energy hyperfaces reveals that the dehydration is kinetically hindered by a significantly high activation barrier. This situation is not essentially altered by taking into account nonspecific solvent effects in aqueous solution.
Copper(II) Complexes of Pyrophthalone and Iminopyrophthalone
Authors: Bontchev P. R. , Mitewa M. , Minchev S. , Kashchieva M. , Mechandjiev D.
Published: December 2004

Kupfer(II)‐komplexe von Pyrophthalon und Iminopyrophthalon

Kupfer(II)‐komplexe von Pyrophthalon (PPH) und Iminopyrophthalon (IPH) wurden synthetisiert und ihre Struktur mit Hilfe von Molekül‐ und ESR‐Spektroskopie und magnetischer Suszeptibilität untersucht. Es wurde festgestellt, daß die Komplexe mit einem Metall‐Ligand‐Verhältnis von 1:2 und mit einer Struktur eines verzerrten Tetraeders gebildet werden.

Die IR‐Daten zeigen daß die koordination durch das O‐Atom der Enol‐From der Liganden und dem N‐Atom des Pyridinringes realisiert wird
Über die Autoxidation von Vinylcylopentan, Vinylcyclohexan und 4‐Vinylcyclohex‐1‐en
Authors: Biela R. , Bilas W. , Ihsan U. , Pritzkow W. , Schmidt‐Renner W.
Published: December 2004

Autoxidation of Vinylcyclopentane, Vinylcyclohexane, and 4‐Vinylcyclohex‐1‐ene

The title olefins were oxidized with molecular oxygen at 75–80°C. About 40% of the oxygen absorbed were found by iodometric titration as peroxidic oxygen. The reaction products were analyzed by a combination of chemical methods, gas chromatography, and 13C‐n.m.r.‐spectroscopy.

Vinylcyclopentane and vinylcyclohexane are attacked preferably at the tertiary allylic C‐H‐bonds giving almost equimolar mixtures of the corresponding allylisomeric hydroperoxides. In the case of 4‐vinylcyclohex‐1‐ene the C‐H‐bonds in position 6 are preferably attacked, but products of attack on the other allylic C‐H‐bonds also could be identified.

In all cases the amount of products which could not be detected gaschromatographically was determined by balance experiments in the presence of an internal standard.
Chloro‐nitrosyl‐molybdän‐Komplexe als Epoxidationskatalysatoren. II. Epoxidringöffnungs‐inaktive Katalysatoren
Authors: Gonzales O. , Schäfer R. , Schnurpfeil D. , Seyferth K. , Taube R. , Mohai B.
Published: December 2004

Chloro‐nitrosyl Molybdenum Complexes as Epoxidation Catalysts. II. Catalysts Inactive in Epoxide Ring‐opening Reaction

Chloro‐nitrosyl molybdenum complexes which are active in the epoxidation reaction do not catalyze the consecutive epoxide ring‐opening reaction if the coordinated ligand can form a strong transition metal‐ligand bond. The temperature of the cleavage of the ligand from the central atom obtained by derivatographic measurements characterizes the strength of this bond. The epoxide ring‐opening activity can be demonstrated by the initial reaction rate, by the conversion of the initial epoxide and by the yield of the ring‐opening products 1 and 2 obtained in the reaction of 1, 2‐epoxyoctane with ethanol in chlorobenzene at 100°C. High temperatures of ligand cleavage correspond with low conversions of the initial epoxide, low initial reaction rate and a low ratio of the isomers 2/1.
Kinetics of Dimerization of Amines by hydrogen peroxide in the presence of ferrous sulphate as catalyst
Authors: Ahmad Iftikhar , Rauf A. M. A. , Saeed Kamal M.
Published: December 2004

Kinetik der Dimerisierung von Aminen durch Wasserstoffperoxid in Gegenwart von Fe(II)SO4 als Katalysator

Die Kinetik der Dimerisierung von Diethyl, n‐Butyl‐ und tert.‐Butylamin durch Wasserstoffperoxid in Gegenwart von Fe(II)‐Ionen wurde untersucht. Die Reaktion ist bezüglich Fe(II)‐Ionen und der Amine 1. Ordnung und 0. Ordnung betreffs Wasserstoffperoxid. Produkte der Dimerisierungsreaktionen sowie einige ihrer kristallinen Derivate wurden erhalten und identifiziert. Die Aktivierungsenergien für Diethyl‐, n‐Butyl‐ und tert.‐Butylamin betragen 153, 130 bzw. 105 KJ mol−1. Ein Reaktionsmechanismus wurde aufgrund der experimentellen Beobachtungen vorgeschlagen.
13C‐NMR‐Untersuchung der interannularen Konjugation in substituierten Pyrazolen
Authors: Mögel L. , Schulz M. , Radeglia R. , Osten H. J.
Published: December 2004

13C‐N.M.R. Investigation of Interannular Conjugation in Substituted Pyrazoles

The correlation of the 13C‐chemical shifts with the Hammet values for substituted 3‐anilino‐1, 5‐diphenylpyrazoles (1a–k) and substituted 3‐methyl‐1, 5‐diphenylpyrazoles (2a–g) provides evidence for extensive interannular conjugation only between the N‐benzene‐and the pyrazole rings, whereas in the capto‐dative disubstituted system 1 extensive conjugation through the whole molecule is possible. The chemical shifts correlate well with the HMO‐calculated π‐electron densities. From a comparison of the chemical shifts of unsubstituted 1 and diphenylamine it can be concluded that the 1,5 ‐diphenylpyrazol‐3‐yl group has the same electronic effect as the phenyl group.
Zur Beeinflussung des Ionisations‐Dissoziationsgleichgewichtes von Tritylhalogenidlösungen in Methylenchlorid bei Zugabe von Styren
Authors: Heublein Günther , Bauerfeind Dietmar
Published: December 2004

Influence of Styren Addition on the Ionization‐Dissociation Equilibrium of Trityl Halides in Methylene Dichloride

The ionization‐dissociation equilibrium in solutions of trityl halides in methylene dichloride is effected by the addition of π‐donors as a function of the temperature. The intensity of the trityl absorption of trityl fluoride and trityl chloride is decreased as it can be shown by u.v.‐spectroscopy. The trityl absorption of trityl bromide solutions in methylene dichloride is very sensitive towards temperature changes. Measurements of the equilibrium constants for the ionization ‐ dissociation‐equilibrium, when styrene is added to the solution, indicate a specific solvation effect by the styrene molecules, however, a stabilization of ion pairs by specific solvation due to styrene molecules does not occur.
Dicyclopentadienoxidation. IV. Oxidation von 4,5‐ und 8,9‐Dihydro‐dicyclopentadien
Authors: Schnurpfeil D. , Lauterbach G.
Published: December 2004

Dicyclopentadiene Oxidation. IV. Oxidation of 4,5‐ and 8,9‐Dihydro‐dicyclopentadiene

A mixture of exo‐ and endo‐4,5‐dihydro‐dicyclopentadiene 5 and also pure endo‐8,9‐dihydro‐dicyclopentadiene 7 and pure exo‐dicyclopentadiene 10 was oxidized in the absence and in the presence of catalysts. The compounds containing the norbornene structure mainly gave the corresponding exo‐epoxides. No catalytic effects were observed in the formation of these nor‐bornene epoxides. Compound 7 containing only the cyclopentene structure mainly yielded the corresponding hydroperoxide 9. In this case a catalytic effect of epoxidation catalysts was observed: in the presence of such catalysts the epoxide was increased.

The results obtained prove the mechanism of dicyclopentadiene oxidation proposed by us.
Acylierung von Heterocyclen mit Kohlensäurederivaten. IV. Umsetzung von Benzoxazolin 2‐thion mit Arylcyanaten. Kinetik und Mechanismus
Authors: Glatt Hans‐Horst , Bacaloglu Radu , Csunderlik Carol , Muntean Doina , Martin Dieter
Published: December 2004

Acylation of Heterocycles with Carbonic Acid Derivatives. IV. Reaction of Benzoxazolin‐2‐thione with Aryl Cyanates. Kinetics and Mechanism

The arylcyanate benzoxazoline‐2‐thione (1) reaction in the presence and absence of the tertiary amines yields 1‐aryloxyiminocarbonylbenzoxazoline‐2‐thione (2) and 2‐thiocyanatobenzoxazole (4). A mechanism is proposed based on the influences of the reactants concentration, the concentration and basicity of tertiary amines, the solvent‐water concentration, the arylcyanate substituents electronic effects on the reaction rate and the apparent activation parameters. This mechanism consists in the nucleophilic attack of the benzoxazoline‐2‐thione S‐atom on the cyanate, followed by rearrangement through a four‐center transition state.
Quantenchemische Berechnungen an Radikalen vom Allyltyp: Cycloalkenyl‐ und Cycloalk‐1‐enylmethylradikale
Authors: Ziegler U. , Ondruschka B.
Published: December 2004

Quantum‐Chemical Calculations on Allyl‐Type Radicals: Cycloalkenyl‐ and Cycloalk‐1‐enylmethyl Radicals

The ability of the MINDO/3‐HE‐method for predicting various molecular properties was tested for cycloalkenyl‐ (1 to 4), cycloalk‐1‐enylmethyl‐(5 to 8), and for the resonance‐stabilized cyclic radicals (9 to 12). Close by it was established that the calculated heats of formation are largely correct. The electronic distribution in the allylic part of 1 to 12 is evidently too levelled.

Based on the defination of allyl resonance energy (ARE ‐ SZWARC (1948)) a mean value for the ARE of 1 to 8 is derived to 55 ± 12 kJ · mol−1.
Darstellung von β‐substituierten trans‐Ethylen‐diphenylphosphinen und ‐sulfiden durch P(O)‐ und P(S)‐aktivierte Olefinierung
Authors: Gloyna Dieter
Published: December 2004

Preparation of β‐Substituted trans‐Ethylene Diphenylphosphines and Sulphides by P(0) and P(S)‐activated Olefination

Methylene bis‐diphenylphosphine monoxide (3c) in tuluene reacts regiospecifically and stereoselectively with aldehydes in the presence of potassium tert‐butoxide to ß‐substituted transethylene diphenylphosphines 6, which can be oxidized to the sulphides 2 by sulphur in acetone. These sulphides 2 are to be obtained also directly from methylene bis‐diphenylphosphine oxide sulphide 3b and methylene bis‐diphenylphosphine disulphide 3d, respectively, under the same olefination conditions. But the yields are smaller and the purification of the raw products is much more difficult, if 3d is used.
Anomalous Reactions of Cyanide with Two Hindered Aromatic Aldehydes
Authors: Gore P. H. , Gupta S. D. , Obaji G. A.
Published: December 2004

9‐Anthraldehyde (1), under the conditions of a benzoin condensation, yields 9‐anthracenecarbonitrile (2). 9‐Cyano‐10‐anthraldehyde (6) has been shown to be the likely intermediate in this reaction. Mesitaldehyde (7), under similar conditions, yields 2‐hydroxy‐2‐mesitylethanoic amide (8).