bluuebunny/crossref_metadata_2025 huggingface dataset:
Reaktionen von Aroyl(Hetaroyl)iminodithiokohlesäureestern mit Carbanionen CH‐acider Verbindungen
Authors: Richter M. , Strauss K. , Augustin M.
Published: December 2004

Reactions of Dimethyl N‐Aroyl(Hetaroyl)carbimidodithioates with Carbanions CH‐acidic Compounds

Reactions of dimethyl N‐aroyl(hetaroyl)carbimidodithioates 1 with carbanions 2 present new possibilities to synthesize 3‐acyl‐amino‐3‐methylthio‐2‐subst.‐acrylnitriles 3 by monosubstitution of methylthiogroup.

The reaction of 1 with 2‐alkyl‐benzothiazolium salts 4 yield deeply coloured N‐acyl‐(2,3‐dihydrobenzothiazole‐2‐yliden) thioacetimido acid‐methylates 5 of the 2‐subst.‐benzothiazoliumperchlorates 6. The structures of the final products are determined by i.r.‐, 1H.‐n.m.r.‐ and u.v.‐spectra.
Photoinduzierte Zersetzung von Aryldiazoniumsalzen durch Metalloxalate
Authors: Baumann H. , Strehmel B. , Timpe H.‐J. , Rehorek D.
Published: December 2004

Photoinduced Decomposition of Arene Diazonium Salts by Metal Oxalates

Arene diazonium salts were decomposed by the irradiation of K3[Fe(oX)3] and K3 [Co(ox)3]. The dediazonation is caused by electron transfer reactions between ·CO‐2 and in the case of the former complex also by [Fe(ox)2]2‐ ‐species. As intermediates aryl radicals were found by spin trapping with nitroso durene. The dediazonation quantum yields (0,15‐‐1,21) depend on the reduction potentials of the salts and on the oxalate concentration. By electron acceptor substituted diazonium salts the values are the same as those of the K3[Fe(ox)3]‐actinometer. In the case of p‐dialkylaminobenzene diazonium salt‐types an electron transfer takes places with ·CO‐2 only whereas the reaction with [Fe(ox)2]2− is neglectable. A Hammett‐correlation for the electron transfer of Fe(II)‐species with a ϱ‐value of 1.7 was found. The investigated systems are efficient initiators of the photopolymerization.
Zur Dehydratisierung von Harnstoffen mit Dichlorcarben im Phasentransfer‐Verfahren, ein Zugang zu substituierten Cyanamiden
Authors: Schroth W. , Kluge H. , Frach R. , Hodek W. , Schädler H. D.
Published: December 2004

The Dehydration of Ureas by Two‐Phase Dichlorocarbene Reaction, a Synthetic Access to Substituted Cyanamides

A wide variety of N,N‐disubstituted ureas are dehydrated in the CHCl3/NaOH catalytic two‐phase system under mild conditions. The sequence of urea‐transamidation and dehydration thus offers a profitable approach to aprotic cyanamides. Among various tested PT‐catalysts tertiary amines prove to be the most efficient and favourable ones. Tertiary amines may also be used advantageously in the transformation of carboxylic amides and thioamides to the corresponding nitriles. The application of the same technique is less suitable in the case of N‐mono‐substituted ureas, N,N′‐ disubstituted ureas as well as N(dialkylaminomethylidene) ureas, because consequent reactions of the primarily formed cyanamides predominate. Problems concerning the dehydration mechanism are elucidated in terms of HMO‐perturbation theory
Säurekatalysierte Umsetzungen von Aromaten mit Alkanen und Cycloalkanen. X. Alkylierungen mit Cyclohexan
Authors: Miethchen Ralf , Steege Sigrid , Kröger Carl‐Friedrich
Published: December 2004

Acid‐catalyzed Reactions of Aromatic Hydrocarbons with Alkanes and Cycloalkanes. X. Alkylations with Cyclohexane

The complex reaction mixtures of the nonconventional alkylation of benzene with cyclohexane in the presence of Lewis/proton acids and promotors were investigated by gas‐liquid chromatography and mass spectrometry. Four representative groups of hydrocarbons were found including cycloalkylbenzenes, substituted indanes or tetralines (C12H16), C1‐C6‐alkylbenzenes and isomeric biscycloalkyls (C12H22). Their formation is interpreted as a competition between alkylation, (without or with isomerization), ringfission with cycloalkylation or fragmentation, and self‐alkylation; phenylcycloalkylcations and phenylalkylcations are the intermediates.
Konfigurative Zuordnung über sterisch definierte Epoxidringe. X. Glycidonitrile. III. Synthese von 4α‐Aryl‐2‐methyl‐1α‐oxaspiro(2,5)octan‐2‐nitrilen
Authors: Fischer F. , Palitzsch P.
Published: December 2004

Determination of Configurations by the Aid of Sterically Corresponding Epoxides. X. Glycidic Nitriles. III Synthesis of 4α‐Aryl‐2‐methyl‐1α‐oxaspiro(2.5)octane‐2‐nitriles

The condensation of 2‐aryl‐cyclohexanones 1a‐‐d with α‐chloropropionitrile at 80° in presence of NaH and in dimethoxyethane yields the corresponding glycidic nitriles. The configuration and the conformation of the C‐2‐isomeric 4α‐aryl‐2‐methyl‐1α‐oxaspiro[2.5]octane‐2‐nitriles 3b‐‐e have been analysed. The ratio of the resulting C‐2‐isomeric glycidic nitriles has been determined.
Dicyclopentadienoxidation. II 5. Katalysierte Flüssigphasenoxidation von Dicyclopentadien
Authors: Schnurpfeil D.
Published: December 2004

Dicyclopentadiene Oxidation. II. Catalyzed Liquid‐Phase Oxidation of Dicyclopentadiene

The liquid‐phase oxidation of dicyclopentadiene 1 by molecular oxygen was studied in the presence of MoO2(acac)2

Acac‐ Acetylacetonat

as a typical epoxidation catalyst. The yield of the mono‐epoxides
2
and
3
is increased to 56,4% (uncatalyzed reaction: 43,6%). The ratio of the two mono‐epoxides is decreased to
2/3
= 2,6 in relation to the uncatalyzed reaction (
2/3
= 7,1). The influence of temperature, conversion and solvents is described. The bisepoxide
4
is formed at lower conversions than in the uncatalyzed reaction. But also at higher conversions of
1
not more than 10% of the bisepoxide
4
is formed
Zum Einfluß von Lösungsmitteln auf das VIS‐Spektralverhalten von 4′‐Dialkylamino‐α‐cyano‐stilben‐4‐diazoniumsalzen
Authors: Walkow F. , Epperlein J.
Published: December 2004

Solvatochromism of 4′‐Dialkylamino‐α‐Cyano‐Stilbene‐4‐Diazonium‐Salts

4′‐Dialkylamino‐stilbene‐4‐diazonium‐salts are deep coloured compounds and give strong solvatochromism. 4′‐Diethylamino‐α‐cyano‐stilbene‐4‐diazonium‐tetrafluoroborate was investigated in 52 different solvents and 3 binary solvent mixtures. With increasing solvent basicity the longest wave lenght absorption maximum (\documentclass{article}\pagestyle{empty}\begin{document}$ \nu^{\hspace{-5pt}\sim}_{\rm max} $\end{document}) decrease. Complex formation by crown ethers causes a decrease of \documentclass{article}\pagestyle{empty}\begin{document}$ \nu^{\hspace{-5pt}\sim}_{\rm max}$\end{document}, too. In solvents with dielectricity constants higher than about 15 dissociation effects superpose solvatochromism. The summary of experimental dates support the approach of specific nucleophilic solvatation of diazonium ions.
Photoinduzierte Elektronentransfer‐Reaktionen von Komplexen der Arendiazoniumsalze mit Kronenethern
Authors: Becker H. G. O. , Israel G. , Pefeiffer D. , Oertel Ulrike
Published: December 2004

Photoinduced Electron Transfer‐Reactions of Arenediazonium Ions Complexed with Crown Ethers

The photolysis (full light of a medium pressure Hg‐lamp) of p‐methylbenzenediazonium‐tetrafluoroborate in the presence of the crown ether 18‐crown‐6 (1) yields mainly the products of a heterolytic dediazoniation via arene cations as intermediates. The quantum yield φges of the photolysis from p‐methoxybenzenediazonium‐tetrafluoroborat in CH2Cl2 decreases in the presence of 18‐ crowns‐6 (1) from 0.66 to 0.08. In contrast to 1, the photolysis of arenediazonium salts in the presence of dibenzo‐18‐crown‐6 (3) yields mainly the products of a homolytic dediazoniation as a consequence of an electron transfer from 3 to the diazonium ion. φges of this reaction increases with decreasing wavelength of the exciting light from 0.09 (436 nm) to 0.32 (366 nm). this wavelength dependence is explained by formation of a correlated radical pair after excitation. In agreement with this situation a photo‐CIDNP‐effect is observed in the 15N‐n.m.r.‐spectra of isotopically labeled arenediazonium salts complexed by 3 and benzo‐18‐crown‐6(2). No photo‐CIDNP‐effect is observed in the presence of 1. This different behaviour of the EDA‐complexes formed by arenediazonium salts with the two different groups of crown ethers 1 and 2, 3 is discussed as a control of the electron transfer‐reaction by the structure of the frontier orbitals.
Synthese und Eigenschaften kristallin‐flüssiger Derivate des Rhodanins
Authors: Weissflog W. , Möckel P. , Kolbe A. , Kresse H. , Pelzl G. , Mohr K. , Zaschke H.
Published: December 2004

Synthesis and Properties of Liquid Crystalline Derivatives of Rhodanine

Substituted benzylidene‐rhodanines 3–8 were prepared both by condensation of 1 a–f with suitable aldehydes and by acylation of 2a–g with substituted benzoyl chlorides or cinnamoyl chlorid. The mesomorphic properties of the compounds are discussed in respect to molecular structure with the aid of i.r.‐, Raman‐ and u.v./vis‐spectra of 3d, 3k, 4, 5, 6g, 8a. We have investigated the dielectric and electrooptic behaviour of 31.
Synthese von 6‐Acetyl‐3‐alkyl‐2‐phenyl‐chromen‐4‐onen in phasentransfer‐katalysierter Baker‐Venkataraman‐Reaktion
Authors: Henning H.‐G. , Schwabe B. , Kernchen F. , Westphal G.
Published: December 2004

Synthesis of 6‐Acetyl‐3‐alkyl‐2‐phenyl‐chromen‐4‐ones by Phasetransfer Catalysed Baker‐Venkataraman Reaction

Three of the five partial steps of the Baker‐Venkataraman xssynthesis of flavones (scheme 1) can be favoured by PTC conditions. In the intermolecular O‐acylations of the 4‐hydroxyacetophenone 1 (A) and the 5‐acetyl‐2‐hydroxy‐acylophenones 3 (C), respectively, the nucleophilicity of the phenolat anions is increased by the PT catalysator. The steric and electronic effects of the substituents in the 5‐acetyl‐2‐benzoyloxy‐acylophenones 4 cause the formation of the 6‐acetyl‐flavones 6 in the phasetransfer catalysed Baker‐Venkataraman rearrangement (D) in one step and in good yields. The over‐all yields of the 1 → 6 reactions are not higher than 30% because of the limiting step (B). This Fries rearrangement of 4‐acyloxy‐acetophenones 2 affords only 32–62% of 3 under drastically enhanced conditions.
15N‐ und 13 C‐NMR‐chemische Verschiebungen sowie 13C‐1H‐, 13C‐15N‐ und 15N‐15N‐Spin‐Spin‐Kopplungskonstanten para‐substituierter Benzendiazoniumsalze
Authors: Gruner M. , Pfeifer D. , Becker H. G. O. , Radeglia R. , Epperlein J.
Published: December 2004

Nitrogen‐15 and Carbon‐13 Chemical Shifts and 13C‐1H, 13C‐15N and 15N‐15N Coupling Constants of Parasubstituted Arene Diazonium Salts

Nitrogen‐15 and carbon‐13 chemical shifts and 13C‐1H,13C‐15N and 15N‐15N coupling constants of 15N‐enriched p‐substituted arene diazonium salts are reported and within the ΔE‐approximation investigated. It is shown that changes of ΔE should be taken into account when considering variation of the nitrogen‐15 chemical shifts. The influence of substituent effects was discussed within the DSP (dual substituent parameter)‐approach.
Elektrochemie organischer Kationen. II. Untersuchungen zum kathodischen Verhalten des Acridiziniumions und zur kathodisch katalysierten Spaltung seines Photodimeren
Authors: Mitzner R. , Bendig J. , Ziebig R. , Graichen F. , Kreysig D. , Pragst F.
Published: December 2004

Electrochemistry of Organic Cations. II. Investigations about the Cathodic Behaviour of the Acridizinium Ion and the Cathodically Catalyzed Cleavage of its Photodimer

The cathodic reduction of the acridizinium ion Az⊕ and of its photodimer (Az⊕)2 in acetonitrile and in dimethylformamide leads via the radicals Az⋅ to the same red electrodimer Az‐Az. In the case of (Az⊕)2 an electrochemically initiated cleavage to Az⊕ is involved. It was shown by cyclic voltammetry, coulometry and homogeneous electron transfer experiments using the anion radicals of some quinones and aromatic hydrocarbons as electron donors that this process occurs by a chain reaction with the dissociative one‐electron transfer from Az⋅ to (Az⊕)2 as the elementary step. The mechanism of the anodic oxidation of Az‐Az, which regenerates Az⊕, was investigated by electrogenerated chemiluminescence. The results are discussed in terms of the sensitized photochemical cleavage of (Az⊕)2.
Polarity of Some Oxime Extractants as determined by gas‐liquid‐chromatography
Authors: Szymanowski J. , Voelkel A. , Beger J. , Binte H.‐J.
Published: December 2004

The polarity index, retention index, coefficient ϱ and partial Gibbs function of one mole of a solute methylene group and the Sevcik A criterion were determined at different temperatures for some aromatic hydroxyoximes and intermediate ketones by means of gas‐liquid chromatography using n‐alkanes as nonpolar agents and n‐alcohols as polar agents. The relations between these parameters and the relations between the polarity and the compound structure were discussed.

In the oxime and ketone molecules the polarity of the hydrophilic groups changes in the following order: OH>NOH>O;and OH>CO>O, respectively. The ketones have less polarity than the oximes. The phenolic hydroxyl group has twice the polarity of the oxime and the carbonyl groups. The chlorine atom at the ortho position in relation to the hydroxyl group sharply increases the polarity.
Zur Reaktion von N‐Aryl‐2,4‐dimethyl‐buta‐1,3‐dien‐1,4‐sultamen mit Tetracyanethylen;1H‐,13C‐ und15N‐spektroskopische Charakterisierung der Tetracyan‐ethylierungs‐ und Tricyan‐vinylierungsprodukte
Authors: Fanghänel E. , Radeglia R. , Bedemann K.‐H. , Mohammed H. , Kriwanek J. , Steinmüller P.
Published: December 2004

About the Reaction of N‐Aryl‐2,4‐dimethyl‐buta‐1,3‐dien‐1,4‐sultames with Tetracyanoethylene;1H,13C and15N N.M.R. Spectroscopic Charcterization of the Products of Tetracyanethylation and Tricyanvinylation

The 4‐methyl group in N‐aryl‐2, 4‐dimethyl‐buta‐1,3‐dien‐1, 4 sultames is CH‐acidic and adds therefore to tetracyanethylene. The adducts easily lose HCN on dissolving in DMSO to form N‐aryl‐2‐methyl‐4‐(2, 3, 3‐tricyanoprop‐2‐ene‐1‐ylidene)‐but‐2‐en‐1, 4‐sultames4, which form sodium salts at C‐1. The structures of the compounds obtained were determined by13C and15N n.m.r. spectroscopy.
31P‐NMR‐Untersuchung und Alkylierung von N‐Hetaryl‐triphenylphosphanimiden: Ableitung von σ−‐Konstanten verschiedener N‐Ringsysteme aus den 31P‐chemischen Verschiebungen
Authors: Bödeker J. , Köckritz A. , Köckritz P. , Radeglia R.
Published: December 2004

31P‐N.M.R. Investigation and Alkylation of N‐Hetaryl‐triphenylphosphanimides: Estimation of σ−‐Constants for Several N‐Ring Systems from the 31P Chemical Shifts

On the basis of a Hammett‐lide relationship we have used the 31P chemical shifts of N‐hetaryl‐triphenylphosphanimides 2 to estimate σ−‐constants resp. σ−‐differences of several N‐heteroaromatic rings. The electron‐withdrawing influence of these rings on the P chemical shift is additionally increased by a short‐range electrical field and magnetic anisotropy effect respectively in case the phosphazene group is linked with the α‐position of the hetarene. If one aza substituent is neighbouring to the detector group, this through space effect leads to a downfield shift of about 7 ppm. All compounds are alkylated with methyliocide at the ring N atoms and give the quaternary salts 3. The pyridine‐N‐oxide derivative 2n exists in the open‐chain form and reacts with methyliodide at the O atom.
Reaktion von (2‐Alkoxy‐vinyl)hetero‐methiniminiumsalzen mit C‐Nukleophilen – ein Zugang zu funktionalisierten Pyryliumsalzen
Authors: Spitzner R. , Schroth W.
Published: December 2004

Reaction of (2‐Alkoxy‐vinyl)hetero‐methiniminium Salts with C‐Nucleophiles — an Approach to Functionalized Pyrylium Salts

The O‐alkylation products 2 of 2‐acyl‐1‐chloro‐enamines 1 (X = Cl) or acylketene‐S, N‐acetales 1 (X = SCH3) respectively react with cyanoactivated methylene compounds 3 under C,C‐bond formation. The reaction products 4 have been converted into functionally substituted pyrylium salts 5 by acidic treatment. Limitations of the synthetic approach are discussed.
3,3‐Bis[alkylthio]‐phenylacrylaldehyde als Bausteine für Thiophene und Pyrazole
Authors: Rudorf W.‐D.
Published: December 2004

3,3‐Bis[alkylthio]‐2‐phenylacrylaldehydes as Building Sets for Thiophenes and Pyrazoles

Alkylation of the dithiolate 2 either with methyliodide and α‐CH‐acid halogenated compounds R2CH2X or only with the latter reagent yields ketene S,S‐acetals 3. Base catalyzed cyclization of 3 leads to the thiophenes 4 Reaction of 3,3‐bis[methylthio]‐2‐phenylacrylaldehyde 3f with hydrazine affords a mixture of aldehydrazone 5 and aldazine 6. The pyrazole 7a is obtained by refluxing 5 in 1‐butanol. Mass spectra of the pyrazoles 7b, c and reaction of 3f with aniline prove the attack of a nucleophile on the formyl group in the first step.
Pyryliumverbindungen. 32 [1]. 2‐Methoxy‐2H‐thiopyrane aus 2,4,6‐Triaryl‐thiopyryliumsalzen
Authors: Zimmermann Thomas , Fischer Gerhard W.
Published: December 2004

Pyrylium Compounds. 32. 2‐Methoxy‐2H‐thiopyrans from 2,4,6‐Triaryl‐thiopyrylium Salts

Reaction of 2,4,6‐triarylthiopyrylium salts 1 with sodium methoxide in absolute methanol yields isolable 2‐methoxy‐2H‐thiopyrans 2, the structure of which was proved spectroscopically. Using the 2,4,6‐triphenyl derivative 2a as model compound, the behaviour of the 2‐methoxy‐2H‐thiopyran system towards some nucleophiles and electrophiles was studied. Thus, on heating with ethanol the 2‐ethoxy‐2H‐thiopyran 3 is formed. Nitromethane and ethyl cyanoacetate react with 2a in the presence of triethylamine to give 2,4,6‐triphenylbenzene (6) and 2,4,6‐triphenylbenzonitrile (7), respectively. Electrophiles (e. g. mineral acids or acyl halides) regenerate from 2a the starting thiopyrylium system; the same principle underlies the formation of 2,4,6‐triphenylthiopyrylium perchlorate (1a) and 2‐methoxy‐3‐methyl‐2,4,6‐triphenyl‐2H‐pyran (5) from 2a and 3‐methyl‐2,4,6‐triphenylpyrylium perchlorate (4).
Estimation of relative Autoxidation Rates of Normal Paraffins, secondary alcohols, and ketones by competitive reactions
Authors: Just Gerhard , Pritzkow Wilhelm , Rudolf Matthias , Tien Tieu Dung , Voerckel Volkmar
Published: December 2004

The relative rates of autoxidation at 140°C in the presence of 0.1% manganeous sterate were determined for 9 normal alkanes, 5 secondary alcohols, and 6 ketones. In the case of the n‐alkanes the oxidation rates increase linearly with the increasing chain length of the hydrocarbon. The oxidation rates of the secondary alcohols are about 3.3 times higher than those of the corresponding alkanes. The oxidation rates of the ketones are about 1.2 times higher than those of the corresponding alkanes.
MO‐LCAO‐Calculations on Polymethines. XXII [1] antiaromatic cyclopentadienyl cations
Authors: Mehlhorn Achim , Fabian Jürgen , Tyutyulkov Nikolay , Olbrich Gottfried , Dietz Fritz
Published: December 2004

Ab initio SCF and semiempirical MINDO/3 and PPP/DCI calculations have been applied to substituted cyclopentamethines which formally resulted from cyclization of streptopentamethines in the α,α′‐positions. These compounds exhibit a typical streptopolymethinic charge distribution of the carbon atoms along the cyclized chain, unique molecular geometries, extremely small energy gaps between the lowest excited states S1, T1 and the ground state S0 as well as large electron affinities. With respect to molecular geometry, spectral behaviour and electron affinity substituted cyclopentamethines are closely related to the antiaromatic cyclopentadienyl cation. Depending on the substitution pattern, the one or the other of the two Jahn‐Teller distorted geometries of the antiaromatic C5H5⊕ appears to be frozen.
Chalkonaziridine. III [1] Zur Reaktion von trans‐Chalkonaziridinen mit Isocyanaten, Isothiocyanaten und HSCN
Authors: Weber Fritz Gerd , Liepert Harald , Köppel Hubert
Published: December 2004

Chalcone Aziridines. III. Reaction of trans‐Chalcone Aziridines with Isocyanates, Isothiocyanates and HSCN

The reaction of 2‐aryl‐3‐aroyl‐aziridines 1 with phenyl isocyanate or mustard oils leads to N‐phenylcarbamoyl derivatives 2a–2q and 2‐amino‐thiazolines 6 a, h, n, r, respectively. From 2 m and NaI the imidazolin‐2‐one 3 was obtained. By treatment of 2 with HSCN the regiosomeres 2(3)‐ureido‐3(2)‐rhodano‐1. 3‐diaryl‐propan‐1‐ones 4 a, h, m and 5 f were formed.
Synthese und Reaktivität von Estra‐1,3,5,(10)‐trienen mit heterocyclischen Vierringen in 14,15‐Stellung
Authors: Ponsold Kurt , Prousa Richard
Published: December 2004

Synthesis and Reactivity of Estra‐1,3‐5(10)‐trienes with Heterocyclic Four‐Membered Rings in 14,15‐Position

3‐Methoxy‐estra‐1,3,5(10),14‐tetraen‐17β‐ol acetate 1 and ‐17α‐ol acetate 2 react with chlorosulfonyl isocyanate in stereospecific manner and good yields to 3‐methoxy‐14β,15β‐[3′,4′‐(N‐chlorosulfonyl‐2′‐oxo‐azetidin)]‐estra‐1,3,5(10)‐trien‐17β‐ol acetate 3 and ‐17α‐ol acetate 4, respectively. Hydrolysis of 3 and 4 in the presence of reducing agents affords the N‐unsubstituted oxo‐azetidines 5 and 6, reduction of which gives the azetidines 9 and 10. Cleavage of the azetidine ring yields the amino acid derivatives 11 and 15, from which the oxooxetanes 12 and 13 and the hydroxy acid derivatives 16 and 17, respectively, are obtained by deamination.
Zur Wechselwirkung von Donoren mit Alkylaluminiumhalogeniden. III. CNDO/2‐Modellrechnungen
Authors: Hallpap P. , Heublein G. , Nieke C. , Reinhold J. , Eizner Y. , Kolstov A. I.
Published: December 2004

The Interaction of Donors with Alkylaluminium Halogenides. III. Model Calculations with the CNDO/2‐Method

The quantum chemical model calculations show, that the Lewis acidity of the compounds (CH3)nAlCl3−n(n = 0…3) decreases with increasing n. The influence of the methyl ligands seems to be additive.

The heterolysis of the RX bond (R = H, CH3; X = Cl, OH, NH2, CH3) is promoted by the cooperation of the Lewis acids (CH3)nAlCl3−n. Fox X = OH, NH2, CH3the energy effort is nearly the same, while it is smaller by a third for X = Cl. Before heterolysis the formation of a complex takes place between the Lewis acid and the donor RX. The complex with HCl is more stable than that with NH3.
Chinoxaline. XXIV. Synthese von 4‐substituierten 1,2,3‐Triazolo[1,5‐a]chinoxalinen
Authors: Vogel M. , Lippmann E.
Published: December 2004

Quinoxalines. XXIV. Synthesis of 4‐Substituted 1,2,3‐Triazolo [1, 5‐a] quinoxalines

3‐Substituted quinoxaline‐2‐carbaldehydes 1 react with tosylhydrazide to give 3‐substituted quinoxaline‐2‐carbaldehyde tosylhydrazones 2. The treatment of 2 with a boiling solution of sodium methoxide or ethoxide – the so called Bamford‐Stevens reaction – leads to 4‐substituted 1,2,3‐triazolo[1,5‐a]quinoxalines 4 in high yields. Some of these compounds were also obtained by thermolysis of 2.
Durch Wasserstoffperoxid ausgelöste Ringverengung von Aminohydroxy‐hexahydrobenzoxazolcarbonsäureamid zu Amino‐cyclopentanspirooxazolinon
Authors: Bischoff Christian , Gründemann Egon , Schröder Edith
Published: December 2004

A Ring Contraction Induced by Hydrogenperoxide

2‐Amino‐7a‐carbamoyl‐3a‐hydroxy‐3a,4,5,6,7,7a‐hexahydro‐benzoxazole (1) and hydrogenperoxide rearrange to 2′‐amino‐cyclopentanespiro‐5′‐oxazolin‐4′‐one (5). 5 and aniline hydrochloride form the phenylaminoderivative 6, 5 and 2,5‐dichlorophenylhydrazine hydrochloride form the 2,5‐dichlorophenylhydrazinederivative 7. 5 and hydrochloric acid afford cyclopentanespiro‐5′‐oxazolidin‐2′,4′‐dione (8). Hydrolysis of 5 or 8 furnish 1‐hydroxy‐cyclopentane‐carboxylic acid (9).
Revisitation of formaldehyde‐aniline condensation. III. The Cyclic Tetramer of N‐Methyleneaniline: An X‐ray diffraction structure determination
Authors: Randaccio Lucio , Zangrando Ennio , Gei Maria H. , Giumanini Angelo G.
Published: December 2004

The cyclic tetramer of N‐methyleneaniline, one of the products from the condensation between formaldehyde and aniline under neutral condition, has been characterized as 1.3.5.7‐tetraphenyltetrazocine (3) and its crystal structure elucidated by X‐ray diffraction.
Zur Kupplung von 4‐substituierten 2‐Pyrazolin‐5‐onen mit p‐Chinondiiminkationen; Nachweis isokinetischer Beziehungen
Authors: Akhlaq M. S. , Grossmann N. , Pasbrig E. , Fanghänel E.
Published: December 2004

On the Coupling of 4‐Substituted 2‐Pyrazoline‐5‐ones with Quinone Diimine Cations; Detection of Isokinetic Relations

The temperature dependence of the rate constant kK of the coupling reaction between pyrazoline‐5‐ones 1a–i and quinone diimine cations 2a, b is determined in dependence of the substituents at the coupling position (R3: H, NNAr,CHAr–pyrazoline‐5‐one). The activation enthalpies are between 7 and 60 kJ mol−1 and the activation entropies between −132 and −19 J mol−1 K−1. An isokinetic relation with β = 106°C is found and a rate determining combination of the carbanions of 1a–i with 2a, b is proposed. Contrary to this, the 2‐pyrazolin‐5‐ones 1j–l, n (R3: SCNH2NR) obey an isokinetic relation with β = −45°C. Taking into consideration the activation parameters, the low dependence of kK on the ionic strength, and the decrease of kK with the increase of the pK values of the couplers, a rate determining splitting off of R3 is assumed.
Electrolytic Behaviour of Some Chlorothallate(III) Compounds in ethanol solution
Authors: Millikan Mary B. , James Bruce D.
Published: December 2004

Raman spectroscopic and conductivity studies show that pyridinium derivatives of the TlCl52⊖, TlCl63⊖ and Tl2Cl93⊖ species dissociate in ethanol solution to yield the TlCl4⊖ ion, but the [(C2H5)4N]2TlCl5 salt does not dissociate further and behaves like a 2:1 electrolyte.
Syntheses of 4‐aroyl and 4‐Disubstituted Hydroxymethyl‐pyridazin‐3(2H)‐ones and Their 3‐Mercapto Derivatives: Synthesis of 1,3‐Dithiano[4,5‐c]pyridazine as a New Ring System
Authors: Shams Nabil A. , Enayat Ebtisam I. , Shalaby Alyaa A. , El‐Abbady Samia A.
Published: December 2004

A number of 4‐aroylpyridazin‐3(2H)‐ones (2a–c), 4‐disubstituted hydroxymethyl‐pyridazin‐3(2H)‐ones (3a–c) and their thio derivatives (3d–f) have been prepared from different Grignard reagents and 5,6‐diphenyl‐4‐cyano(1a), 4‐carbethoxy (1b)pyridazin‐3(2H)‐ones and 3‐mercapto derivatives (1c and d). The structures of the compounds prepared were inferred from their elemental analysis, spectral data and from the identity of some of them with authentic samples.
Intramolecular Charge Transfer Luminescence of a donorethylsubstituted pyridinium ion
Authors: Pragst F. , Mitzner R.
Published: December 2004

The dimethoxyphenyl‐ethyl‐substituted pyridinium ion 1 shows a long‐wave absorption and fluorescence, which are attributed to an intramolecular electron donor‐acceptor complex. In contrast to electrically neutral complexes the fluorescence quantum yield of 1 in polar solvents is comparatively high and the radiative decay time is rather small. The excited complex can also be generated by electrochemical methods.
Synthese und Polymerisation ungesättigter Benzaldazine
Authors: Moszner N. , Hartmann M. , Wermann K. , Schütz H. , Jancke H.
Published: December 2004

Synthesis and Polymerization of Unsaturated Benzaldazines

The preparation of methacrylic and acrylic acid derivatives of isomeric hydroxybenzaldazines and their characterization by u.v.‐, i.r.‐,1H and13C n.m.r. spectroscopy are described. By radical polymerization and copolymerisation with styrene and methyl methacrylate, respectively, crosslinked polymers showing ultraviolet‐absorbing properties are obtained.
Untersuchungen zum UV/Vis‐Spektralverhalten von Azofarbstoffen. XVIII. Substituenteneinflüsse auf die Absorptionsmaxima der n → π*– und π → π*‐Banden von 4‐N,N‐Diethylaminoazobenzenen
Authors: Hassner Carmen , Mustroph H.
Published: December 2004

Studies on UV/Vis Absorption Spectra of Azo Dyes. XVIII. Substituent Effects on the Absorption Maxima of the n → π* and π → π* Bands of 4‐N,N‐Diethylaminoazobenzenes

The spectra of 27 substituted 4‐N.N‐diethylaminoazobenzenes are determined. The band systems can be separated by deconvolution into two Gaussian curves. The results so obtained show that the effects of substituents on n → π* and π → π* transitions are similar and that electron withdrawing substituents in the phenylazo residue cause a bathochromic shift of both the n → π* and the π → π* bands.
Organische Elektronenleiter und Vorstufen. V. Synthese von Poly(organylthio‐acetylenen)
Authors: Richter A. M. , Richter J. M. , Beye N. , Fanghänel E.
Published: December 2004

Organic Electron Conductors and Precursors. V. Synthesis of Poly (organylthio‐acetylenes)

Poly(bis‐organylthio‐acetylenes) 2 and poly(mono‐organylthio‐acetylenes) 3 have been synthesized by complex catalyzed polymerization of the corresponding acetylenes (4 resp. 5). Yields and properties of the polymers 2, 3 depend on reaction conditions, the catalyst and the nature of the acetylenes. Relations between these influence factors are discussed.
Über die Thermische Umsetzung von Mono‐n‐alkylbenzenen
Authors: Zychlinski W. , Bach G. , Zimmermann G. , Sokolovskaja V. G. , Shevelkova L. V. , Guselnikov L. E.
Published: December 2004

Thermal Reaction of Mono‐n‐alkyl‐benzenes

The pyrolysis of ethyl‐(1), n‐propyl‐(2), n‐hexyl‐(3) and n‐octylbenzene (4) has been studied under conditions of steam cracking (600 to 800°C) in a laboratory scale tubular reactor. The overall activation energies determined for (1) to (4) were found to be nearly identical (221 to 227 kJ · mol−1) obviously caused by similar initial steps. The main liquid product observed was styren accompanied by ω‐phenyl‐1‐alkenes and α‐olefins. Benzene is an important side product of 1. It might be formed mainly by a hydrogen assisted dealkylation via a cyclohexadienyl type radical as reactive intermediate.
Ein einfacher Weg zur Herstellung chlorsubstituierter Arylazobenzen‐, Arylazonaphthalen‐ und Arylazopyrazol‐Derivate
Authors: Günther R. , Jähne E. , Hartmann H. , Schulze M.
Published: December 2004

A Simple Route for the Synthesis of Chlorosubstituted Arylazobenzenes, Arylazonaphthalenes, and Arylazopyrazoles

The reaction of arylazophenoles and arylazohydroxypyrazoles (or their tautomer hydrazones) 10, 11, and 15 with POCl3 in dimethylformamide yields chlorosubstituted arylazobenzenes or arylazopyrazoles 12, 13, and 16, resp., in moderate to high yields.

The substitution of the OH‐group by the Cl‐moiety is favoured by acceptor substituents in the aryl fragments ortho‐ and/or para‐linked to the azo group.

In case that arylazocompounds derived from resorcinol are used the substitution reaction runs in a stepwise manner giving raise to the formation of o‐hydroxy‐p‐chlorosubstituted azo compounds 18 primarily and then of dichlorosubstituted azo compounds 19.
Über den Druckeinfluß auf die Katalysierte Flüssigphasenoxidation von cis‐ und trans‐Oct‐4‐en
Authors: Schnurpfeil D. , Hronec M.
Published: December 2004

About the Influence of Pressure on the Catalyzed Liquid‐Phase Oxidation of cis‐ and trans‐Oct‐4‐ene

The investigation of the influence of pressure on the liquid‐phase oxidation of cis‐ and trans‐oct‐4‐ene shows that the reaction rate increases up to 491 kPa in the non‐catalyzed oxidation reaction, but up to 981 kPa in the MoO2(acac)2‐catalyzed reaction n‐oct‐1‐ene reacts more slowly than cis‐ and trans‐oct‐4‐ene as well in the pressure‐less reaction as in the oxidation under pressure. In the non‐catalyzed oxidation reaction the cis/trans‐ ratios don't depend on the pressure, but in the MoO2(acac)2‐catalyzed oxidation reaction the cis/trans‐epoxide ratios increase with increasing pressure. The optimum of the reaction temperature lies between 110 and 130°C.
Synthesis of Imidazoles by reaction of N‐benzylated amidines with carboxylic acid derivatives
Authors: Liebscher Jürgen , Feist Kersten
Published: December 2004

2‐Amino‐N‐heterocycles, such as 2‐aminopyridine 7 or 2‐aminobenzimidazole 16 as well as benzamidines 19 possessing a N‐(4‐nitrobenzyl)‐substituent react as N‐C‐N‐C‐synthons with formamide chlorides 5, formamide acetals 2 or acetic anhydride (C1‐building blocks) with formation of imidazole compounds 9, 17 or 22, respectively in the presence of triethylamine. In some cases, intermediate N‐acetylation (20) or N‐formylation products 21 are isolated.
Über die Katalyse der Cooxidation von cis‐Oct‐4‐en und n‐Butyraldehyd
Authors: Schnurpfeil D. , Just G. , Kraft F. , Seyrich A.
Published: December 2004

The Catalysis of the Co‐Oxidation of cis‐Oct‐4‐ene and n‐Butyric Aldehyde

The co‐oxidation of cis‐oct‐4‐ene and n‐butyric aldehyde in the absence of catalysts, or in the presence of molybdenum and Co(acac)3, resp., was studied in dependence on the aldehyde/olefin ratio, on the temperature and other reaction conditions. Under the same conditions, the noncatalyzed co‐oxidation converted 50%, the MoO2(acac)2‐catalyzed one 68%, and the Co(acac)3‐catalyzed one 40% of the reacted olefin into the epoxide.

The cis/trans‐epoxide ratio in the molybdenum‐catalyzed co‐oxidation was nearly 2 independent of the aldehyde/olefin ratio. In the non‐catalyzed co‐oxidation the cis/trans‐epoxide ratio depends linearly on the aldehyde/olefin ratio (cis/trans E. = 0,58 + 0,90 n/n). From these dependences we can conclude that the homolytic mechanism of epoxide formation decreases and the polar mechanism (Priležaev‐reaction) increases with increasing aldehyde/olefin ratio.

Optimization of the epoxide yields according to a Box‐Hunter experimental plan gave the following reaction conditions to yield 95% epoxide based on reacted olefin: 70°C, ΔnS/n = 0,49, n/n = 3,5 · 10−3, n/n = 0,53. The co‐oxidation in the presence of other molybdenum catalysts of the chloro‐nitrosyl‐complex type and of the carbonyl‐complex type as well as the co‐oxidation with other aldehydes were studied, too.
Fotosensibilisierte Ausbleichung von Azomethinfarbstoffen
Authors: Grossmann N. , Wehner V. , Weise A. , Winnig B. , Fanghänel E.
Published: December 2004

Fotosensitized Fading of Azomethine Dyes

The quantum yields of photofading of the azomethine dyes 1a—h were determined in the presence of the sensitizers benzophenone (B), michler's ketone (MK) and anthracen (A), in isopropanol and benzene. In isopropanol, excluding oxygen, the leuco dyes 5 are formed by benzophenone in high quantum yield (Φ = 0.4). Photofading also takes place using Michler's ketone (Φ ≅ 3 · 10−3) and anthracene (Φ ≅ 1 · 10−4), but 5 was not found. With benzophenone (Φ
≅ 7 · 10−3), Micher's ketone (Φ ≅ 1 · 10−3) and anthracene (Φ ≅ 1 · 10−4) as sensitizers the chromophore of 1a—h were destroyed, when oxygen was present. The photofading with benzophenone and Michler's ketone is a result of radicalic processes.

Radical scavangers 8 and 9, therefore, give a strong decrease of the quantum yield of photofading. The photofading in benzene corresponds to the results in isopropanol considering the lower potential of this solvent for photoreduction processes.
Photochemie diarylsubstituierter 2H‐Tetrazole. VI. Quantenausbeuten der Photolyse diarylsubstituierter 2H‐Tetrazole
Authors: Lohse V. , Leihkauf P. , Csongar Ch. , Tomaschewski G.
Published: December 2004

Photochemistry of Diarylsubstituted 2H‐Tetrazoles. VI. Quantumyields of the Photolysis of Diarylsubstituted 2H‐Tetrazoles

The photoexcitation of diarylsubstituted 2H‐tetrazoles in ethanol in the presence of methylmethacrylat (MMA) yields quantitatively 1,3‐diaryl‐Δ2‐pyrazolines. The photoreactions investigated are spectroscopically uniform. The influence of the substituents on the quantum yields of the photolysis of 2H‐tetrazoles (1a—1x) is discussed.
Pyrazolinon‐Ringschluß unter Alkoxywanderung
Authors: Kirschke Klaus , Kuban Ralf‐jürgen , Schulz Burkhard
Published: December 2004

Pyrazolinone Ring Closure with Alkoxy Migration

Alkyl 3‐(4‐nitro‐phenylazo)‐2‐brom‐2‐butenoates (1a, b) with morpholine undergo substitution of the bromo group and ring closure connected with a migration of the alkoxy group forming 4‐alkoxy‐3‐methyl‐4‐morpholino‐1‐(4‐nitro‐phenyl)pyrazolin‐5‐ones (2a, b).
Synthesis, characterization, spectral and antifungal properties of some 5‐Substituted‐1,3,4‐oxadiazole‐2‐thiones and their mannich bases
Authors: Holla B. Shivarama , Kalluraya Balakrishna , Nath S. C.
Published: December 2004

A series of 5‐substituted aryloxymethyl‐1,3,4‐oxadiazole‐2‐thione (3a–e) and their Mannich bases 4–8 are synthesized and subjected to fungitoxic screening. The structures of these compounds are established on the basis of elemental analysis 1H‐n.m.r. and mass spectral data. The mass spectral fragmentation pathways of these compounds are discussed.
Solvatochromic Behaviour and Prototropic Studies of some oxazolones of electron donor‐acceptor type
Authors: Antonious M. S. , Habashy M. M. , El‐Sayed Y. A.
Published: December 2004

Solvatochromic and halochromic behaviour in the u.v.‐vis absorption spectra of some substituted 4‐arylidene‐2‐aryloxazol‐5‐ones (1–5) are studied. Positive and negative solvatochromism, depending on the substituent present, are observed in different hydrogen bonding donoracceptor (HBD‐A) and hydrogen bonding acceptor (HBA) solvents. However, in non hydrogen bonding (NHB) solvents all compounds show a positive solvatochromism. A considerable intramolecular charge transfer interaction, between the donor and acceptor parts in the oxazolones studied, is observed. Small fluorescence quantum yields are observed for the oxazolones. In triethanolamine‐acetone mixtures, the visible absorption spectra of the hydroxy substituted oxazolone shows an additional long‐wavelength band suggesting the existance of prototropic equilibria. The prototropic equilibrium constants at different temperatures are determined.
Wasserlösliche disulfonierte aromatische Ketone — Photophsikalische und photochemische Eigenschaften
Authors: Kronfeld K.‐P. , Timpe H.‐J.
Published: December 2004

Water Soluble Disulphonated Aromatic Ketones — Photophysical and Photochemical Properties

By the sulphonation of benzophenone, xanthone, thioxanthone, acridone, and methylacridone the disulphonated derivatives BPS, XS, TXS, AcS and MAcS are produced. Their disodium salts are well soluble in water. The absorption and the emission spectral data of these ketones are similar to those of the respective parent compounds. The S1 state of BPS alone is of n — π* type, in all the other cases it possesses mainly π — π* character. The S1 states can serve as donors in electron transfer reactions with iodonium salts. The kinetic curves of flash photolysis of these ketones in water show two decay processes, which are attributed to the triplet state and the long living ketyl radical. The triplet absorption spectra of the disulphonated ketones are very close to those of the unsubstituted ketones, but the life times of the former are much higher. The T1 are quenched through onium salts by electron transfer reactions. Acryl amide, too, acts as a quencher for the triplets.
Zur Pyrolyse von 3‐Ethylpent‐2‐en – Ein weiterer Hinweis auf eine Homoallyl‐Umlagerung
Authors: Bach G. , Zychlinski W. , Kopinke F.‐D. , Zimmermann G.
Published: December 2004

Pyrolysis of 3‐Ethylpent‐2‐ene — a Further Evidence for a Homoallylic‐Rearrangement

The pyrolysis of 3‐ethylpent‐2‐ene has been studied under conditions of steam cracking in the temperature range 600—700°C in a laboratory scale tubular reactor. The main products of decomposition were methane, 2‐ethylbutadiene and isoprene. The majority of products obviously arose from H abstraction and radical addition, typical for radical chain reactions in olefins decomposition including phenomena resulting from allylic resonance. The formation of isoprene, however, could only be explained by a reaction network including a homoallylic rearrangement.
Zur Kinetik der photoinduziertenRadikalpolymerisation mit Elektronendonator/Elektronenakzeptor‐Initiatorsystemen
Authors: Timpe H.‐J. , Oertel U. , Zücker I. , Müller G.
Published: December 2004

Kinetics of Photoinduced Radical Polymerization with Electron Donor/Electron Acceptor Initiator Systems

By means of benzyltriphenylphosphonium tetrafluoroborate (P⊕) and anthracene (An) as photoinitiator system and methylmethacrylate (MMA) as monomer the influences of several reaction parameters on the polymerization quantum yield Φp, were studied. The following principal reactions proceed: electron transfer between excited An (1An) and P⊕salt (kq= 2,5 · 109M−1s−1), quenching of1An by MMA (k= 1,3 · 107M−1s−1), reaction between a1An…P⊕salt complex and MMA. The last reaction is assumed, since from the disappearance of An and the formation of An cation radical, respectively, rate constants k> 108M−1s−1have been calculated. Furthermore, it is assumed, that only the quenching of1An by MMA (Φp= 3,8) and the addition of free radicals, produced by the photoinduced electron transfer, lead to polymer formation. Kinetic equations were developed, which can explain the effect of P⊕‐salt concentration, light intensity and MMA concentration on Φpdata. The quotient obtained for kp/kis in the range of 0,053 to 0,087 M−0,5s−0,5, depending on the used experimental parameters. Polymerization degrees Pnof 260–590 were found, which also depend on the experimental parameters.
Zur Reaktion von atomarem Wasserstoff mit Cyclopenten und Cyclohexen in der Gasphase
Authors: Gebhardt J. , Scherzer K.
Published: December 2004

About the Reaction of Hydrogen Atoms with Cyclopentene and Cyclohexene in the Gas Phase

The reaction of hydrogen atoms with cyclopentene and cyclohexene has been investigated in an isothermal flow‐system (298 K) at a pressure of 130 Pa. 12 products of the cyclopentene reaction and 17 products of the cyclohexene reaction were identified by gas chromatography. The quantitative studies show, that the main reactions of the cyclopentene system are the hydrogenation to cyclopentane and the chemical activated decay to methane; cyclohexene reacts especially by hydrogenation to cyclohexane and ring‐isomerisation to methylcyclopentane.
2,3‐Heterokondensierte Thiophene aus substituiertem 2‐Aminothiophen‐3‐thiol
Authors: Gewald K. , Hain U. , Madlenscha M.
Published: December 2004

2,3‐Heterocondensed Thiophenes from Substituted 2‐Aminothiophen‐3‐thiole

Ethyl 5‐amino‐4‐mercapto‐3‐methyl‐thiophen‐2‐carboxylate (2), obtainable from the appropriate thienylthiocyanate 1 by reduction, undergoes reactions in analogy to the 2‐aminobenzenthiole. Thus, with formic acid or trimethylorthoacetat the thieno [2,3‐d]thiazoles 4 and 5 are formed. Aromatic aldehydes yield the thieno[2,3‐d]thiazolines (6) which can be dehydrogenated by sulphur to form 9. From carbon disulfide and 2 the thieno[2,3‐d]thiazol‐2‐thione (7) is formed. With phenacylbromide or ethyl bromoacetate 2 can be converted into the thieno[3,2‐b] thiazine derivatives 11 or 12. Diazotation of 2 yields the thieno[2,3‐d]1,2,3‐thiadiazole derivative (14).
Photochemie von Bis‐2H‐tetrazolen. III. Nachweis von Bisnitriliminen durch Tieftemperatur‐UV‐Spektroskopie und thermische Folgereaktionen durch Photolyse von Bis‐2H‐tetrazolen
Authors: Weinberg P. , Csongar Ch. , Gessner M. , Tomaschewski G.
Published: December 2004

Photochemistry of Bis‐2H‐tetrazoles. III. Detection of Bisnitrilimines through Low‐Temperature‐UV‐Spectroscopy and Thermic Consecutive Reactions through Photolysis of Bis‐2H‐tetrazoles

The photolysis of 2H‐tetrazoles (1) leads to nitrilimines. Bis‐2H‐tetrazoles form correspondingly bisnitrilimines 2. They were detected directly by the photolysis of bis‐2H‐tetrazoles (1) in an ethanol/ether glass at 95 K. The absorption maxima are depend in an expected manner on the substituents. In the presence of dipolarophiles the reaction of bis‐2H‐tetrazoles (1) at room temperature gives bis‐Δ2‐pyrazolines (3). These reactions can also be explained by a photoreaction of bis‐2H‐tetrazoles (1) to bisnitrilimines 2 at 95 K and subsequent cycloaddition above 150 K. Some bis‐Δ2‐pyrazolines (3) are described.

The photolyses of bis‐2H‐tetrazoles (1) to the bisnitrilimines 2 proceed as one step eliminations of two molecules of nitrogen.
Tetrazolverbindungen. 3. Modifizierung von (1‐Aryl‐1H‐tetrazol‐5‐yl)‐acetaldehyd‐Enaminen durch säurekatalysierte Umaminierung
Authors: Fischer G. W.
Published: December 2004

Tetrazole Compounds. 3. Modification of 1‐Aryl‐1H‐tetrazole‐5‐acetaldehyde Enamines by Acid‐Catalyzed Transamination

The acid‐catalyzed transamination of tetrazole‐5‐acetaldehyde enamines proves to be a useful synthetic method for preparing specially N‐substituted enamines of this series not accessible directly from 3‐chloro‐propeniminium salts 3 and sodium azide. Thus, starting from (E)‐1‐aryl‐5‐(2‐dimethylamino‐vinyl)‐1H‐tetrazoles 5 transamination with dialkylamines yields tertiary enamines of types 6 and 7. Analogously, acid‐catalyzed reaction of 5 with N‐alkylanilines leads to 1‐aryl‐5‐[2‐(N‐alkylanilino)‐vinyl]‐1H‐tetrazoles 8. Bifunctinal secondary amines such as N,N′‐dimethylethylenediamine result in systems of type 9 with two linked tertiary tetrazolyvinylamino groups. All the transaminations with secondary amines proceed with retention of configuration. According to the same reaction scheme transamination of 5 (Ar = Ph) with primary alkyl‐, aralkyl‐, and arylamines affords secondary tetrazolylvinylamines 10; however, here the formation of Z‐configurated products dominates. Bifunctional primary amines like ethylenediamine and 1,2‐phenylenediamine react with 5 to give the N,N′‐linked systems 11 and 12 possessing two secondary tetrazolylvinylamino groups. – Characteristic i.r., u.v., and 1H‐n.m.r. spectroscopic data of the novel tetrazole‐5‐acetaldehyde enamines are reported.
Preparation of 2‐Aroyl‐3‐methyl‐1H‐1,4‐benzothiazines. ESR Study of 2‐benzoyl‐1,3‐dimethyl‐1H‐1,4‐benzothiazine
Authors: Isakander George M. , El Shiekh El Khawad Ibrahim , Zahran Hassan B. , Schlemper Elmer O.
Published: December 2004

2‐Aroyl‐3‐methyl‐1 H‐1,4‐benzothiazine ylids (2a–k) were prepared by alkylation of the corresponding 4H‐benzothiazines 1. The ylids 2 are labile at room temperature; proper analytical and 1H‐n.m.r. data were obtained for their picrates. E.s.r. studies of u. v. irradiated polycrystalline form of (2; R1 = Me, R2 = H) gave evidence for a long‐lived benzothiazinyl radical with the odd electron residing on nitrogen 6.
Studies of tertiary amine oxides. 11. Rearrangement of Acetylenic Amine Oxides
Authors: Khuthier Abdul‐Hussain , Sheat Mohammed Ali
Published: December 2004

Sixteen acetylenic amine oxides (5a–p) were prepared by the oxidation of the corresponding tertiary amines (4a–p) with m‐chloroperbenzoic acid. The N‐oxides are thermally unstable and undergo a rearrangement when stirred in an inert solvent yielding O‐allenyl hydroxylamines (6). The rearrangement proceeds by an intramolecular cyclic mechanism.
Pyryliumverbindungen. 42. Benzocycloalkenone und Dihydro‐2H,7H‐1‐benzopyranone aus 2,4,6‐Triaryl‐pyryliumsalzen und Cycloalkan‐1,2‐dionen
Authors: Zimmermann T. , Fischer G. W. , Olk B. , Findeisen M.
Published: December 2004

Pyrylium Compounds. 42. Benzocycloalkenones and Dihydro‐2H,7H‐1‐benzopyranones from 2,4,6‐Triarylpyrylium Salts and Cycloalkane‐1,2‐diones

2,4,6‐Triarylpyrylium salts 1 react with cycloalkane‐1,2‐diones 2 in the presence of an appropriate condensing agent to yield benzocycloalkenones 3. Thus, sodium acetate and cyclo‐hexane‐1,2‐dione (2a) lead to the dihydro‐2H‐naphthalenones 3a–i, whereas with cycloheptane‐1,2‐dione (2b) and piperidine acetate, triethylamine or sodium acetate the tetrahydro‐5H‐benzo‐cyclohepten‐5‐ones 3j–r are formed. As shown for the example 3a, j → 4a, b, benzocycloalkenones of type 3 can be converted into phthalazines 4 on heating with hydrazine in ethanol. By reaction of the dione 2a and an equimolar mixture of triethylamine and acetic acid or morpholine acetate with the salts 1 5,6‐dihydro‐2H,7H‐1‐benzopyran‐8‐ones 5 are obtained as a result of a new type of ring transformation. The pyrans 5 can be cleaved with perchloric acid in ethanol to 5,6,7,8‐tetrahydro‐8‐oxo‐1‐benzopyrylium perchlorates 6. If the pyrans 5 are heated with sodium acetate in ethanol, a conversion to benzocycloalkenones 3 is achieved (cf. 5a → 3a). The structure of the new compounds was established by spectroscopic methods.