bluuebunny/crossref_metadata_2025_split huggingface dataset:
Über die Addition von Nitrosylhydrogensulfat an Olefine
Authors: Kisan Werner , Pritzkow Wilhelm 
Published: January 2005

AbstractDurch Addition von Nitrosylhydrogensulfat an trisubstituierte Olefine in flüssigem Schwefeldioxid als Lösungsmittel sind die entsprechenden α‐Sulfatooxime zugänglich. Die Sulfatooxime sind zersetzlich. Sie reagieren mit Nucleophilen unter Austausch der Sulfatgruppe; die Reaktion verläuft wahrscheinlich nach einem Eliminierungs‐Additions‐Mechanismus über Nitrosoolefine als kurzlebige Zwischenprodukte. Setzt man Nitrosylhydrogensulfat in Gegenwart von Schwefelsäure und von niederen gesättigten Kohlenwasserstoffen mit trisubstituierten oder asymmetrisch disubstituierten Olefinen un und hydrolysiert das Gemisch dann vorsichtig mit Wasser bzw. mit wässerigen Lösungen von Ammoniak oder Natronlauge, so erhält man in guten Ausbeuten die entsprechenden α‐Hydroxyoxime. Setzt man Nitrosylhydrogensulfat mit Eisessig‐Lösungen von unsubstituierten Cycloolefinen um, so erhält man in mäßigen Ausbeuten die entsprechenden α‐Acetoxyoxime.
Nucleoside von Fluorzuckern. XVI. Halogensubstitutionen und Konfigurationsumkehr am Lactolring vom 6′‐Fluor‐D‐glucopyranosyl‐thymin
Authors: von Janta‐Lipinski M. , Etzold G. , Langen P. 
Published: January 2005

Nucleosides of Fluorine Carbohydrates. XVI. Halogene Substitutions and Inversion of Configuration at the Lactol Ring of 6′‐Fluoro‐D‐glucopyranosyl Thymine1‐(6′‐Deoxy‐6′‐fluoro‐β‐D‐glucopyranosyl)‐thymine 1 reacts with equimolar amounts' of tosyl chloride to give the 2′‐O‐tosyl derivative 2. Treatment of 1 with mesyl chloride gives predominantly a derivative with three sulfonyl groups in the molecule.2 reacts both with bromides and iodides but not with fluorides to give the corresponding 2′‐deoxy‐2′‐halogeno derivatives. 2 can be transformed into an 2,2′‐anhydronucleoside 10 that reacts with HCl, HBr and HF/AlF3 to give the 2′‐chloro‐, 2′‐bromo‐, and 2′‐fluoro derivatives of 1‐(2′,6′‐dideoxy‐6′‐fluoro‐β‐D‐glucopyranosyl)‐thymine 7, 12, and 13 respectively.Hydrogenation of 7 affords the 6′‐fluoro analog of the nucleoside phosphorylase inhibitor “deoxyglucosyl thymine” possessing a defined β‐configuration.The alkaline hydrolysis of the anhydronucleoside 10 yields the 1‐(6′‐deoxy‐6′‐fluoro‐β‐D‐mannopyranosyl)‐thymine 15, the epimer of 1.
Halogenlipide. I. Massenspektrometrische Strukturuntersuchung stellungsisomerer Fettsäureester der Halogenpropandiole (Desoxyhalogen‐glyceride)
Authors: Kraft R. , Brachwitz H. , Etzold G. , Langen P. , Zöpfl H.‐J. 
Published: January 2005

Halogenolipids. I. Mass Spectrometric Structure Investigation of the Isomeric Halogeno‐propanediols Esterified with Fatty Acids (Deoxyhalogeno‐glycerides)The mass spectrometric behaviour of the isomers of cytostatic effective halogeno‐propanediols esterfied with fatty acids (deoxyhalogeno‐monoglycerides and deoxyhalogeno‐diglycerides) are investigated. The unambiguous structure of individual isomers is deduced from the characteristic fragmentation patterns of mass spectra. The synthesis of the mentioned compounds is described.
Umsetzung von 2,3‐Dichlormaleinimiden mit Ethoxycarbonylmethylentriphenylphosphoran und Folgereaktionen
Authors: Augustin M. , Schneider B. , Köhler M. 
Published: January 2005

Reaction of 2,3‐Dichloromaleimides with Ethoxycarbonylmethylenetriphenylphosphorane and Secondary Reactions2, 3‐Dichloromaleimide 1a reacts with ethoxycarbonylmethylenetriphenylphosphorane under alkenylation to give 3, 4‐dichlor‐5‐ethoxycarbonylmethylidene‐3‐pyrrolin‐2‐one 2. With N‐substituted 2, 3‐Dichloromaleimides 1b–1f one chloroatom is substituted to give 2‐(ethoxycarbonyltriphenylphosphoranyl)‐methylene‐3‐chloro‐maleinimides 3. The reactions of 2 and 3a with various nucleophiles are investigated.
Synthese von 2‐Heterocyclidenamino‐1,3‐diazatrimethincyaninen
Authors: Fanghänel E. , Richter A. M. 
Published: January 2005

Synthesis of 2‐Heterocyclidenamino‐1, 3‐diaza‐trimethincyaninesThe synthesis of 2‐[3‐methyl‐benzthiazol‐(1, 3)‐inylidene‐(2)‐amino]‐ and of substituted 2‐[1, 3‐dithiolyliden‐(2)‐amino]‐1, 3‐diaza‐trimethincyanines is described. The heterocyclic imines 1 react with phosgene or thiophosgene to the corresponding ureas 2 and thiureas 3, respectively. Alkylation of 3 to the 2‐alkylmercapto‐1, 3‐diaza‐trimethincyanines 4 and subsequent condensation with imine 1 yields the dyes 5. The chemical and spectroscopical data of cyanines 5 are described.
Gibberelline. CIII. Synthese von 8‐Amino‐gibbanen
Authors: Hung Ph. D. , Adam G. 
Published: January 2005

Gibberellins. CIII. Synthesis of 8‐Amino‐gibbanesFor investigations of the structure‐activity relationships of gibberellin phytohormones the synthesis of 8‐amino‐gibbanes is described. The reaction pathway involves condensation of gibberellin C (1a) and its methylester 1b with primary amines to the corresponding azomethins 1c–11 followed by stereoselective NaBH4‐reduction to 8α‐amino gibbanes 2a–2r.
Der „Nornialisierungsfaktor”︁ für die Toinatenmutante chloronerva. XV. Peptidanaloga des Phytosiderophors Nicotianamin
Authors: Ripperger H. , Schreiber K. , Faust J. 
Published: January 2005

The “Normalizing Factor” for the Tomato Mutant chloronerva. XV. Peptide Analogues of the Phytosiderophore NicotianamineSome peptide analogues of the phytosiderophore nicotianamine, (2S, 3′S, 3″S)‐N‐[3‐(3‐amino‐3‐carboxypropylamino)‐3‐carboxypropyl]‐azetidine‐2‐carboxylic acid, have been synthesized from protected amino acids by the EEDQ or the DCC method. They exhibited no biological effect with regard to the phenotypical normalization of the tomato mutant chloronerva.
About nitrile‐formamide‐chloride‐adducts. IX. Synthesis of 1,3‐ or 1,5‐disubstituted 1,2,4‐triazoles by the reaction of nitrile‐formamide chloride‐adducts and their products of hydrolysis with hydrazines
Authors: Liebscher Jürgen , Rumler Andrea 
Published: January 2005

Abstract2‐Aza‐3‐chloro‐2‐propeniminium salts 5, which are easily available by the addition of formamide chlorides 1 to nitriles 2 react smoothly with hydrazines 9 giving rise to 1,3‐disubstituted 1,2,4,‐triazoles 11. When the 2‐aza‐3‐chloro‐2‐propeniminium salts 5 are hydrolysed first the resulting N‐acyl‐formamidinium salts 6 react with hydrazines 9 to 1,5 disubstituted 1,2,4‐triazoles 13 via isolable N‐acyl‐formamidrazones 12.
β‐Fur‐2‐yl‐α‐halogenacrylonitrile. I. Darstellung von β‐Fur‐2‐yl‐ß‐aminoacrylonitrilen und β‐Fur‐2‐yl‐α‐aminoacrylonitrilen
Authors: Jähnisch K. , Seeboth H. , Krause E. , Callejas D. R. 
Published: January 2005

β‐Fur‐2‐yl‐α‐halogenacrylonitriles. I. Preparation of β‐Fur‐2‐yl‐ß‐aminoacrylonitriles and β‐Fur‐2‐yl‐α‐aminoacrylonitrilesβ‐Fur‐2‐yl‐α‐halogenacrylonitriles 1 react with secondary amines to yield β‐fur‐2‐yl‐ß‐aminonitriles 2 and β‐fur‐2‐yl‐α‐aminoacrylonitriles 3. The 1 H‐n.m.r. spectra of the E/Z isomers are discussed.
Synthese und Reaktionsverhalten von N‐(3‐Chlorbenzo[b]‐thiophen‐2‐carbonyl)imino‐Dithiokohlensäure‐Derivaten
Authors: Richter M. , Augustin M. , Strauss K. 
Published: January 2005

Synthesis and Reaction Behaviour of N‐(3‐Chlorobenzo[b]thiophene‐2‐carbonyl)‐imino‐dithiocarbonic Derivatives3‐Chlorobenzo[b]thiophene‐2‐carbonyl‐chloride 1 was treated with potassium rhodanide to afford the appropriate acyl isothiocyanate 3, which adds nucleophilic agents as amines and thioles in good yields.Addition of methanethiole and subsequent alkylation of the dithiocarbamate 7 gives S, S‐dimethylimino‐dithiocarbonate 8. 3‐Chlorobenzo[b]thiophene‐2‐carboxamide 2 reacts with carbon disulphide and phenyl isothiocyanate by chlorine substitution and cyclisation to benzo[b]thieno[2, 3‐e]thiazines 9, 10 or 11. The structure of the final products were determined by analytical and spectroscopical dates.
Prostaglandine und Prostaglandinvorstufen. Untersuchungen zur Synthese von 8‐Methylprostansäurederivaten
Authors: Schwarz S. , Weber Gisela , Meyer M. , Schick H. , Welzel H.‐P. 
Published: January 2005

Prostaglandins and Prostaglandin Intermediates. Synthetic Approach to 8‐Methyl Prostanoic Acid DerivativesStarting from the chiral key‐product 1 the 8‐methyl prostanoic acid derivative 13 was prepared within 10 steps. Construction of the α‐side chain involves DIBAH‐reduction of the lacton moiety of 1 followed by Wittig‐olefination with a C5‐ylide. C1‐Homologation of the oxo group of 1 via cyanhydrin synthesis and Wittig‐olefination with a C7‐ylide are important steps to form the ß‐side chain of compound 13.
Studies on the Autoxidation of Phenylacetylene
Authors: Pritzkow Wilhelm , Rao Tarigopula Siva Sankara 
Published: January 2005

AbstractPhenylacetylene is oxidized slowly by molecular oxygen at 110°C. The main oxidation products are benzoic acid, benzoic anhydride, and benzaldehyde. Besides the oxidation, thermal dimerization, oligomerization, and polymerization processes also take place. As individual products 1,4‐diphenylbut‐1‐yn‐3‐ene and 1,3,5‐triphenylbenzene were identified. About 80% of the phenylacetylene consumed are converted into products of low volatility which could not be detected by gas chromatography.The autoxidation of acetylenic hydrocarbones [1] preferably yields products of the attack at CH bonds in α‐position to the CC triple bond. An attack at the CC riple bond was a first proved in the case of phenylacetylene, which besides polymeric products yielded benzaldehyde, acetophenone, and organic acids [2]. Later, in the causes of the isomeric octynes [3] and of various 1‐Phenylalk‐1‐ynes [4] an attack at the CC triple bond was also proved. As the primary products of the oxidative attack at the CC triple bond short‐lived oxirenes or their valence isomers, the corresponding ketocarbenes are to be expected. Indeed, their rearrangement products were found in the oxidation mixtures of both the isomeric ocytnes [3] and the 1‐phenylalk‐1‐ynes [4]. Other products of the oxidative attack at the CC triple bond are lower carboxylic acids, formally produced by oxidative cleavage of the CC triple bond [3, 4].
NMR‐Spektroskopische Untersuchungen an 2‐Acetyl‐3‐amino‐acrylsäureestern
Authors: Michalik M. 
Published: January 2005

N.M.R. Spectroscopical Investigations on 2‐Acetyl‐3‐aminoacrylatesThe 2‐Acetyl‐3‐aminoacrylates 3 exist as Z/E‐isomers, in which intramolecular H‐bonds are formed between NH and acetyl or ester groups. The E‐isomers are favoured due to the greater acceptor ability of the acetyl compared with ester group. In arylamino substituted compounds 3 a linear correlation with σp constants have been found for 1H chemicals shifts of CH and NH protons and for 13C chemical shifts of C‐2 and C‐3, respectively, representing an optimal transmission of substituent effects through the enamino system.The barriers of rotation around the CC‐bond of 3 have been determined by d n.m.r.spectroscopy. From coalescence phenomena the free activation enthalpies ΔG≠ of rotational process are determined and discussed with respect to substituent effects, a thermal rotational mechanism is postulated.
Determination of relative Autoxidation Rates of Simple Alkylaromatic Hydrocarbons by competitive reactions
Authors: Pritzkow Wilhelm , Thomas Gerda , Willecke Lothar 
Published: January 2005

Relative rates of oxidative attack at the CH bonds in α‐position to the aromatic nucleus were determined for 10 simple alkylaromatic hydrocarbons. The results obtained by competitive oxidations of binary mixtures were shown to be consistent. From these results and the regioselectivity data already published, relative reactivities referring to the tertiary CH bond of cumene were calculated for all CH bonds of the hydrocarbons studied.As expected, p‐alkyl groups increase the reactivity of CH bonds in α‐position to the aromatic nucleus. On the other hand, large alkyl groups, bound to the α‐C atoms, decrease the reactivity of the α‐CH bonds.
ortho‐Spezifische Bromierung von Phenolen
Authors: Schmitz Ernst , Pagenkopf Ingeborg 
Published: January 2005

Ortho‐Specific Bromination of PhenolsPhenol as well as 3‐substituted phenols are brominated exclusively in the orthopositions by N.N‐dibromomethylamine, yielding 2.6‐dibrominated phenols in excellent yields. Phenols bearing an ortho‐substituent need N‐bromomethylamine as the brominating agent to take up one bromine atom into the free ortho‐position. para‐Bromination is not observed in either case. 1‐Naphthol gives 2‐bromo‐1‐naphthol, 8‐hydroxyquinoline gives 7‐bromo‐8‐hydroxyquinoline with 80% and 98% yield respectively. ortho‐Specific chlorination of phenols was carried out in some cases using N‐chloro‐alkylamines.
Cyclisierungsreaktionen β,γ‐ungesättigter Kohlensäurederivate. IX. Regiochemie der elektrophilen Cyclofunktionalisierung β,γ‐ungesättigter Carbamidsäureester mit Brom – Synthese von Oxazolidin‐2‐onen und Tetrahydro‐2H‐1,3‐oxazin‐2‐onen
Authors: Mühlstädt M. , Olk B. , Widera R. 
Published: January 2005

Cyclization Reactions of β,γ‐Unsaturated Derivatives of Carbonic Acid. IX. Regiochemistry of Electrophilic Cyclofunctionalization of β,γ‐Unsaturated Carbamic Acid Esters with Bromine – Synthesis of Oxazolidine‐2‐ones and Tetrahydro‐2H‐1,3‐oxazine‐2‐onesN,N‐Disubstituted β,γ‐unsaturated urethanes (1) and bromine react in methylene chloride at room temperature. The crotyl urethanes (1a–1c and 1e) and bromine give mixtures of corresponding saturated urethanes (dibromine adducts) (2a–2c and 2e), the oxazolidine‐2‐ones (3a–3c and 3e), and the tetrahydro‐2H‐1,3‐oxazine‐2‐ones (4a–4c and 4e). The reaction of γ,γ‐dimethylallyl urethanes (1f–1h) with bromine gives similar results. A useful synthetic route to N‐substituted tetrahydro‐2H‐1,3‐oxazine‐2‐ones (4l–4q) is demonstrated by the reaction of cinnamyl urethanes (1l–1q) with bromine.
Untersuchungen zur Sensibilisierung von Azofarbstoff‐Perhalogenid‐Systemen
Authors: Haessner Carmen , Epperlein J. 
Published: January 2005

Investigations Concerning Sensitization of Silver Free Information Recording Materials with Azo Dyes and Polyhalogen CompoundsRecording materials mentioned in the title are sensitive to the visible region of light. The reason therefore is an energy transfer from the azo dye to the polyhalogen compounds, preferentially CBr4. It's possible to separate the absorption spectra of azo compounds used in this work into two gaussian functions, which relates to n,π*‐ and π,π*‐transitions. Only the excitation of the n,π*‐transition causes sensitization. A mechanisms of sensitization is proposed.
Reaktionen geminaler Dithiolate mit (Z)‐1,4‐Dichlor‐but‐2‐en
Authors: Rudorf W.‐D. , Schwarz R. , Augustin M. 
Published: January 2005

Reactions of Geminal Dithiolates with (Z)‐1,4‐Dichloro‐but‐2‐eneGeminal dithiolates 2 and 7 react with (Z)‐1,4‐dichloro‐but‐2‐ene either to give 4‐vinyl‐1,3‐dithiolanes 3 or 4, 7‐dihydro‐1,3‐dithiepines 4 and 8, respectively. Another method for the synthesis of 4 and 8 is the reaction of ketene dichlorides 5 or isocyanide dichloride 9 with the disodium salt of (Z)‐but‐2‐ene‐1,4‐dithiol. The formation of the corresponding 1,3‐dithiolanes can be excluded in these cases. 1H‐ and 13C‐n.m.r. spectra are in accordance with the structures and are discussed.
Synthese von 8H‐1,2,4‐Triazolo[4,3‐a]perimidinen
Authors: Burkhardt U. , Johne S. 
Published: January 2005

Synthesis of 8H‐1,2,4‐Triazolo[4,3‐a]perimidinesReaction of 2‐hydrazinoperimidine (3) with carboxylic acids or its orthoesters leads to 8H‐1,2,4‐triazolo[4,3‐a]perimidines (5a–h). 3 and aldehydes yield the aldehydehydrazones (6b,c,d) which are converted in 5 by air oxidation. The structures of the new compounds were determined by means of i.r., u.v., 1H‐n.m.r. and mass spectroscopy.
Zur Umkupplung von 4‐Arylazo‐2‐pyrazolin‐5‐onen mit p‐Chinondiiminkationen
Authors: Fanghänel E. , Akhlaq M. S. , Grossmann N. , Willscher U. 
Published: January 2005

Recoupling of 4‐Arylazo‐2‐pyrazoline‐5‐ones with p‐Quinonediimine Cations4‐Arylazo‐2‐pyrazoline‐5‐ones (1a–j) readily undergo coupling reaction with p‐quinonediimine cations (2a, b) to form azomethin dyes (3a, b). The dependence of the rate constants kK of the dye formation on the substituents of 1a–j as well as on the ionic strength show that the rate‐determining step of the coupling reaction is the formation of the intermediate 4 in a bimolecular reaction between the carbanions of 1a–j and p‐quinonediimine (2a, b).It became evident that the benzenediazoniumion (5a–j) is eliminated in the reaction of 4 to 3a, b. Under the coupling conditions used, substituted benzene is formed in the reduction reaction of 5a, b by the p‐phenylendiamine (7a, b) or by the leuco dye (6a, b).
A study on Claisen Condensation with Diethyl Anilinodiacetate
Authors: Metwally Mohamed Abbas , Afsah El‐Sayed M. 
Published: January 2005

AbstractSodium hydride prompted reactions of diethyl anilinodiacetate 1 with acetophenone, p‐nitroacetophenone, p‐fluoroacetophenone and acetylthiophene result in the formation of tetraketones 3a–d. Evidence is presented to support the formation of 3a–d, via a sequence of reactions involving condensation with hydrazine, their acetyl derivatives, and cyclization with polyphosphoric acid. The structures of the hitherto unknown ring systems have been confirmed by i.r., p.m.r. and mass spectral data.
Bipyridines. XIX. Synthesis of some novel 2,7,9,10‐Tetraazaphenanthrene derivatives
Authors: Kaczmarek Łukasz 
Published: January 2005

Abstract[4,4′‐Bipyridine]‐3,3′‐diamine (1) reacts with HNO2 in H2SO4 to form 2,7,9,10‐tetraazaphenanthrene (2) and 9H‐pyrrolo[2,3‐c:5,4‐c′]dipyridine (3) instead of expected bipyridinediol 4 or furodipyridine 5. On the other hand, diazotization of 1 in hydrohalogenic acids leads to novel 3‐halogeno‐2,7,9,10‐tetraazaphenanthrenes 10 or 11 and this reaction represents a new type of regioselective nucleophilic substitution of hydrogen atom in heteroaromatic species. The proposed pathway of reactions was supported by an experiment with the hypothetic intermediate, i.e. 2,7,9,10‐tetraazaphenanthrene‐9‐imine (8), which was obtained on independent route.
Synthesis of biologically active 4‐benzyl‐1(2H)‐phthalazinones and 2‐aryl‐3(2H)‐1‐benzal‐isoindolinones
Authors: Bedair A. H. , Lamphon R. Q. , Ghazal S. A. El 
Published: January 2005

Abstract4‐Benzyl‐2‐1(2H) phthalazonyl derivatives of type 2, 3, 5a, b were synthesized by Mannich reaction of 4‐benzylphthalazinone 1 which by the reaction with diazomethane yielded O‐methylated derivative 4. Various 1‐benzal‐2‐substituted aryl‐3(2H) isoindolinones 7a–f, 8a–e were also prepared. Its i.r., 1H‐n.m.r. and mass spectra were discussed. Some of them exhibit pronounced antimicrobial activities.A number of phthalazinones have found application in clinical medicine [1–3] due to the their pronounced antipyretic, analgesic and tuberculostatic activity and the importance of some benzylidenephthalimidines as stabilisers for halogen containing high polymers [4] and the local anesthetic activity superior to that of procaine [5], tempted us to procure some new phthalazinones and isoindolinones with biological interest.
Aromatenstrukturtypenanalyse von raffinierten Erdölprodukten durch UV‐Spektroskopie
Authors: Deutsch K. , Kühn H.‐J. , Polzin M. , Deutsch I. , Grunow S. , Stöcker J. 
Published: January 2005

AbstractAromatic Structure Type Analysis of Hydrotreated Petroleum Fractions by U.V.‐Spectroscopy20 K boiling cuts were produced from hydrotreated petroleum products by means of distillation. From such close fractions, defined pure aromatic types can be separated by preparative elution adsorption chromatography (EAC) on dual‐packed (Silicagel‐Alumina gel) columns. The extinction coefficients of the various separated types are measured at suitable wave lengths and used for calculating the average extinction coefficients of aromatic types for wide boiling fractions. Utilizing these values on quantitative u.v.‐analysis of technical hydrotreated products, the results correspond well with those of EAC and 1H‐n.m.r. spectroscopy.
Investigation of the dimethyl acetal formation during the Ozonization of Alkenes in methanol
Authors: Theil Fritz , Schick Hans 
Published: January 2005

AbstractDimethyl acetal formation during the ozonization of olefins in methanol followed by reduction with dimethyl sulfide has been occasionally reported in the literature. This acetalization can be completely suppressed, when the ozonization is carefully monitored by g.l.c. or t.l.c. analysis and stopped immediately after the consumption of the olefin. It was proved that the acetal formation observed earlier is the result of an acid catalysed reaction accelerated by dimethyl sulfide and dimethyl sulfoxide present in the reaction mixture. The acidic catalyst is formic acid formed from methanol by oxidation with excessive ozone.
Verbesserte Synthese von 8‐Amino‐2‐methyl‐4‐phenyl‐1,2,3,4‐Tetrahydroisochinolin
Authors: Ivanov T. B. , Mondeshka Diana M. , Angelova Ivanka G. 
Published: January 2005

An Improved Synthesis of 8‐Amino‐2‐methyl‐4‐phenyl‐1,2,3,4‐TetrahydroisoquinolineThe regioselectivity of the reaction of 2‐nitrobenzylmethylamine (1) and styrenoxide (2) leading to a mixture of the isomeric aminoalcohols 3a and 3b has been studied. The course of the reaction strongly depends on the type of the solvent used as reaction medium. The highest selectivity (3a:3b = 9:1) was achieved with a combination of polar aprotic and protic solvents (DMFA and ethanol). 1H n.m.r. spectroscopy was used for identification of the isomers as well as for the determination of their ratio in the crude reaction mixtures. The isomer ratio remains unaffected during catalytic reduction (Ra‐Ni) of 3a/3b to a mixture of the corresponding aminoalcohols 4a and 4b. Pure 3a, 4a and 4b were independently synthesized for comparison. Cyclodehydration of crude 4a/4b mixtures gives 5 in a very good yield.
Chromium(III) compounds as catalysts for Hydrocarbon Oxidation and hydroperoxide decomposition
Authors: Blau Karla , Kovacs O. , Lauterbach Gerlinde , Makhoul M. , Pritzkow W. , Tien Tieu Dung 
Published: January 2005

AbstractChromium stearate and chromium acetylacetonate are very active catalysts both for the oxidation of hydrocarbons by molecular oxygen and for the decomposition of organic hydroperoxides. During these reactions they also catalyze the oxidation of secondary alcohols to the corresponding ketones by organic hydroperoxides. From organic hydroperoxides and chromium(III)compounds chromium (VI) compounds are formed which are probably the effective agents oxidizing secondary alcohols to ketones.
Spintrapping‐Untersuchungen zum Verhalten des Pentacarbonylrhenium‐Radikals
Authors: Rehorek D. , Martino Silvana Di , Kemp T. J. 
Published: January 2005

Spin Trapping Investigations on the Behaviour of the Pentacarbonyl Rhenium RadicalBoth ·Re(CO)5 and ·Re2(CO)9⊕ radicals have been spin‐trapped by nitroso compounds during the photolysis of [Re2(CO)10] at room temperature in CH2Cl2 solution. Interaction with nucleophiles Nu, such as pyridine, PPh3, AsPh3, and SbPh3, led to ·Re(CO)4Nu radicals. Although only ·Re(CO)4PPh3 gave a persistent spin adduct with nitrosodurene, the formation of the other substitution products was evidenced by their increased reactivity towards carbon halides. In the presence of dioxygen, superoxide is formed and trapped.