bluuebunny/crossref_metadata_2025_split huggingface dataset:
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 SaltsNitrogen‐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 PhotodimerThe 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

AbstractThe 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 TricyanvinylationThe 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 ShiftsOn 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 SaltsThe 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 PyrazolesAlkylation 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 SaltsReaction 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

AbstractThe 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

AbstractAb 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 HSCNThe 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‐Position3‐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‐MethodThe 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] quinoxalines3‐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 Hydrogenperoxide2‐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

AbstractThe 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 RelationsThe 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

AbstractRaman 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

AbstractA 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

AbstractThe 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 BenzaldazinesThe 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‐DiethylaminoazobenzenesThe 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‐benzenesThe 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 ArylazopyrazolesThe 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‐eneThe 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

Abstract2‐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 AldehydeThe 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.