bluuebunny/crossref_metadata_2025_split huggingface dataset:
Grafische und numerische Analyse Temperaturabhängiger Fluoreszenzquantenausbeuten
Authors: von Löwis of Menar Michael , Bendig Jürgen , Siegmund Manfred 
Published: December 2004

Graphical and Numerical Analysis of Temperature Dependent Fluorescence Quantum YieldsThe graphical and numerical analysis of temperature dependent fluorescence quantum yields is a suitable method to derive the number and the temperature behaviour of various radiationless processes which are involved in the deactivation of a fluorescent excited state.In this paper eight fluorophore/solvent‐systems were analysed, (T from 77K to 320 K) both, numerically and graphically. A computer program (SLAMS) was developed. It bases on a nonlinear regression and produces deactivation parameters and statements concerning the statistics of data, too. The possibilities, preferences and limits of the numerical analysis are discussed in comparison with the graphical method. The calculated results are discussed with regard to the number of radiationless processes, the accuracy of the quantum yield determination and the investigated temperature range.For the physical interpretation of the kinetic parameters of deactivation in addition to the authors results values from the literature were used.
Photochemische Primärprozesse von Xanthenfarbstoffen. II. Blitzlichtspektroskopische Untersuchungen zum Einfluß von anionischen Mizellen auf die photochemischen Primärprozesse von Selenopyronin
Authors: Ortmann W. , Kassem A. , Fanghänel E. 
Published: December 2004

Photochemical Primary Processes of Xanthene Dyes. II. Investigations of the Influence of Anionic Micelles on the Primary Processes of Selenopyronine by Flash ExcitationIn aqueous solutions containing anionic micelles, the dye cations of selenopyronine are present at the micellar surface. If the concentration of the dye ions is much lower than the concentration of micelles, only monomolecular triplet decay (k1aM = 2 · 10−3s−1) is observed. Under these conditions, the half‐oxidized and half‐reduced form of selenopyronin is not formed. If the concentration of the dye ions is much higher than the concentration of micelles, two or more dye ions are present at every micelle, and a fast bimolecular decay of the triplet state during the flash is observed. The quenching of the triplet state with p‐benzoquinone (k7aM = 1,9 · 109 l/mol s), DABCO (k10aM = 1,6 · 107 l/mol s) and EDTA (k11aM = 1,3 · 105 l/mol s) and the decay processes of the half‐reduced and half‐oxidized form in the micellar solution are investigated.
3‐α‐Bromacetyl‐cumarine als Synthesebausteine für Heterocyclisch substituierte Cumarine
Authors: Czerney P. , Hartmann H. 
Published: December 2004

3‐α‐Bromacetyl‐coumarines as Synthones for Heterocyclic Substituted Coumarines3‐α‐Bromacetyl‐coumarines 2 react easily and in high yields with thiourea and thioamide derivatives 3 and 5, resp., to 4‐coumar‐3′‐yl‐thiazoles 4 and 6, resp., as well as with N,N‐disubstituted thioamides 11 and N,N,N′,N′‐tetraalkylthiourea 12 to 5‐coumar‐3′‐yl‐oxathioliumsalts 13 and 14, respectively. In a two‐step reaction 2 can be transformed by reaction with aniline 17 to 4‐coumar‐3′‐yl‐imidazoles 21 and 5‐coumar‐3′‐yl‐oxazoliumsalts 22, resp., via aminoketone intermediates 18.
Pyryliumverbindungen. XVIII, 2‐Alkoxy‐2H‐pyrane aus tetra‐ und pentasubstituierten Pyryliumsalzen
Authors: Fischer Gerhard W. , Zimmermann Thomas , Weissenfels Manfred 
Published: December 2004

Pyrylium Compounds. XVIII. 2‐Alkoxy‐2H‐pyrans from Tetra‐ and Pentasubstituted Pyrylium SaltsAlkali alkoxides add regioselectively to 2,3,4,6‐tetrasubstituted pyrylium salts 7 (R' H), affording high yields of colourless crystalline 2‐alkoxy‐2H‐pyrans 9. The latte are also formed simply on refluxing 7 in the corresponding alcohol with triethylamine as proton acceptor. 3,5‐Dialkylsubstituted 2,4,6‐triarylpyrylium salts react analogously. The 2H‐pyran structure of the adducts obtained follows from their n.m.r., i.r., u.v. and mass spectra as well as from their reaction with tetracyanoethylene to cycloadducts of type 10. Acids regenerate from 9 the original pyrylium cations, whereas reaction of 9 with nitromethane or ethyl cyanoacetate provides benzene derivatives. ‐‐ The novel starting pyrylium salts 7b‐‐o are characterized by u.v./vis data and by transformation into the corresponding pyridine derivatives
Effect of metal ions in organic synthesis. XI. Hydrolysis and Alcoholysis of Some Acylhydrazines and N‐acyl‐N′‐arenesulphonylhydrazines in the presence of copper(II) chloride
Authors: Attanasi Orazio , Serra‐Zanetti Franco , Battistoni Paolo , Fava Gabriele 
Published: December 2004

Zur Wirkung von Metallionen in der organischen Synthese. XI. Hydrolyse und Alkoholyse einiger Acylhydrazine und N‐Acyl‐N′‐arensulfonylhydrazine in Gegenwart von Kupfer (II)‐chloridDie Hydrolyse und Alkoholyse einiger Acylhydrazine und N‐Acyl‐N′‐arensulfonylhydrazine in Gegenwart von Kupfer(II)‐chlorid · 2 H2O wurden untersucht. Das Mesitylensulfonylhydrazid und die 2,4,6‐Triisopropylbenzensulfonylhydrazid‐Derivate sind reaktiver als die entsprechenden Hydrazine oder Tosylhydrazid‐Derivate.Die entsprechenden Carbonsäuren und Ester erhält man in guten Ausbeuten und unter sehr milden Bedingungen. Die vorliegende Methode ist einfach und bequem im Vergleich zu anderen Methoden. Die Reaktion verläuft wahrscheinlich über Kupferkomplexe der Acylhydrazine.
1,3‐Dipolar Cycloaddition Reactions between some C‐aryl nitrogen oxides with electron‐deficient dipolarophils
Authors: Nour‐El‐Din Ahmed M. , Mourad Aboul‐Fetouh E. 
Published: December 2004

AbstractBoth C‐(2‐methylphenyl)‐N‐phenyl and C‐(3‐methylphenyl)‐N‐phenyl nitrones (1a, b) reacted with N‐phenylmaleinimide and fumaronitrile to give the normal primary cycloadducts. The reaction of the two nitrones (1a, b) with 4‐phenyl‐1,2,4‐triazoline‐3,5‐dione and diacetylacetylene afforded rearrangement products. The unexpected 1,3,4‐oxadiazolidin‐2‐ones were isolated from reaction with phenylisocyanate. In contrast, tetracyanoethylene forms charge‐transfer complexes with both nitrones instead of cycloaddition products. The structural elucidation of the reaction products was made on the bases of the elemental analysis as well as i.r. and 1H‐n.m.r. spectral data.
Tetrathiafulvalene. XIX. Synthese und Eigenschaften elektronenleitender Poly‐Dithiolenkomplexe mit Ethylentetrathiolat und Tetrathiafulvalentetrathiolat als Brückenliganden
Authors: Poleschner H. , John W. , Hoppe F. , Fanghänel E. , Roth S. 
Published: December 2004

Tetrathiafulvalenes. XIX. Synthesis and Properties of Electron Conducting Poly‐Dithiolene Complexes with Ethylene Tetrathiolat and Tetrathiafulvalene Tetrathiolat as Bridge Ligands[1,3]‐Dithiolo[4,5‐d]‐1,3‐dithiol‐2,5‐dione7and 5‐(5‐oxo[1,3]‐dithiolo[4,5–d]1,3‐dithiole‐2‐ylidene)[1,3]‐dithiolo[4,5–d]1,3–dithiol‐2‐one8were synthesised from 1,3‐dithiole‐2‐thione‐4,5‐dithiolat. The ligands react with salts of iron, cobalt, nickel, palladium, platinum and copper to give the polymer complexes22a–gand23a–e, respectively. Irradiation of7in the presence of iron penta‐, dicobalt octa‐ or nickel tetracarbonyl gives the corresponding dithiolene complexes21a–c.The amorphous insoluble polymer complexes from types21, 22, and23have been characterised by i.r.‐spectroscopy, susceptibility and conductivity measurements.The nickel complexes have the highest electrical conductivity (σRT∼ 10−1Ω−1cm−1, pellets) with a very low activation energy (0,045 eV, 100–300 K)A high electron delocalization in the direction of the polymer chain and an easy charge transfer from chain to chain is supposed.
Mehrfunktionelle N‐Tenside. VII. Substitution und Eliminierung bei der Reaktion von 1,2‐Dihalogenalkanen mit Aminen
Authors: Beger J. , Meerbote E. 
Published: December 2004

Polyfunctionalized N‐Tensides. VII. Substitution and Elimination in the Reaction of 1,2‐Dihalogenoalkanes with Amines1, 2‐Dichloroalkanes, 1, 2‐dibromoalkanes and mixtures of 1‐bromo‐2‐chloroalkanes and 1‐chloro‐2‐bromoalkanes react with primary or secondary amines and give both elimination and substitution products, often in a nearly 1:1 proportion.The elimination products are the cis and trans‐1‐halo‐1‐alkenes, the 2‐halo‐1‐alkenes, the 1,3‐and 2, 4‐dienes and the 1‐alkenes. The main substitution products are the 1, 2‐bis‐aminoalkanes. Physical dates, 1H‐n.m.r.‐spectra, surface tension values and CMC‐dates are given.
Thermitase – eine thermostabile Serinprotease. II. Synthese von substratanalogen Peptidchlormethylketonen als potentielle irreversible Enzyminhibitoren
Authors: Jahreis Günther , Smalla Kornelia , Fittkau Siegfried 
Published: December 2004

Thermitase – A Thermostable Serine Protease. II. Synthesis of Substrate Analogous Peptide Chloromethyl Ketones as Irreversibly Acting InhibitorsThe preparation of dipeptide to pentapeptide chloromethyl ketones of alanine wth variation of the amino acid in the P1 and P2 positionNomenklatur für die individuellen Aminosäurereste der Peptide nach I. Schechter u. A. C. Berger, Biochem. Biophys. Res. Commun. 27, 157 (1967).

of the peptides is described. The synthesis is performed by fragment condensation of N‐acylated amino acids or peptides with the unprotected chloromethyl ketone derivatives of amino acids and peptides, respectively. Some examples of enzyme inactivation by peptide chloromethyl ketones are discussed.
The Autoxidation of 1‐Phenylalk‐1‐ynes. Proof of oxirenes as intermediates in the oxidation of acetylenes
Authors: Dao Le Thi Anh , Blau Karla , Pritzkow Wilhelm , Schmidt‐Renner Wolfgang , Voerckel Volkmar , Willecke Lothar 
Published: December 2004

AbstractIn the autoxidations of 1‐phenylprop‐1‐yne, 1‐phenylbut‐1‐yne, and 1‐phenyl‐3‐methylbut‐1‐yne a considerable attack at the CC triple bond takes place. Both products of the oxidative cleavage of the CC bond and products formed through the corresponding oxirenes were detected. The oxirenes rearrange via the isomeric ketocarbenes to ketenes, which yield the corresponding carboxylic acids or their esters. A part of the intermediate ketenes is oxidized with decarboxylation to lower ketones. All products were identified and quantitatively determined after LiAlH4 reduction to the corresponding alcohols.
Eine neue Synthese zur Darstellung von organischen Tellurverbindungen unter Verwendung von elektrochemisch erzeugten Polytelluriden
Authors: Merkel G. , Berge H. , Jeroschewski P. 
Published: December 2004

A Novel Synthesis of Organic Tellurium Compounds by the Use of Electrochemically Generated Polytelluride‐ionsThe cathodic polarisation of a tellurium electrode in aprotic solutions gives rise to polytelluride anions, which react with alkylhalides to the corresponding disubstituted ditellurides. By this method of electrosynthesis a number of organic ditellurides can be simply prepared and without danger. Dialkylditellurides of the general formula R‐Te‐Te‐R (2a–r) can be produced with high yields. The reaction with α,ω‐dihalides gives heterocycles, which involve one or two tellurium atoms in the ring (5a–d, 6–8). The electrochemical reduction of tellurium in the presence of methyliodid yields trimethyltelluroniumiodid (9).
Action of grignard reagents on 6‐(α‐styryl)pyridazin‐3(2H)‐ones; synthesis of some 4‐Substituted 6‐(α‐Styryl)‐pyridazin‐3(2H)‐ones
Authors: Ismail M. Fekry , Shams Nabil A. , El‐Khamry Abdel Momen A. , Mostafa Omnia E. A. 
Published: December 2004

Abstract6(α‐Styryl)pyridazin‐3(2H)‐ones (1a–e) reacted with phenylmagnesium bromide and/or methylmagnesium iodide to give the 1,4‐addition products, 4‐phenyl and/or 4‐methyl‐6‐(α‐styryl)pyridazin‐3(2H)‐ones (3a–e). The structures assigned to the products are established by electronic and infrared spectroscopy and by synthesis of authentic samples in most cases.
Untersuchungen zum Photochromie‐ und Thermochromie‐Effekt an Benzilphenylhydrazonen
Authors: Müller U. , Timpe H.‐J. , Gustav K. 
Published: December 2004

About the Photochromic and Thermochromic Effect of Benzil PhenylhydrazonesBenzil phenylhydrazone1synthesized from benzil and phenylhydrazine possesses s‐trans‐E configuration detected by means of quantum chemical calculations and its spectral data. Upon irradiation a photochromic process proceeds with a λ‐shift Δ λ ≈ 80 nm. The photoproduct has an s‐cis‐Z configuration. The quantum yields of the EZ‐isomerization measured by spectroscopic methods depend on solvent (ΦEZ= 0,077 in CH3OH, ΦEZ= 0,22 in n‐hexane), but are independent of the excitation wavelengths and O2. Benzil N‐methylphenylhydrazone2is inactive under stationary irradiation. Both the Z/E‐isomerization of1and2are be sensitized by benzil and m‐methoxyacetophenone. On the basis of kinetic measurements the quantum yields of sensitized reactions of1are calculated (Φ= 0,43; Φ= 0,57). In protic solvents benzil phenylhydrazone1has thermochromic properties caused by E/Z‐isomerizations. The measured activation parameters of these reactions are small. It is assumed that both the photoinduced and thermal isomerizations proceed via azo intermediates, as indicated by flash photolysis experiments.
2‐Arylamino‐thiophen‐3‐carbonsäurederivate
Authors: Schäfer H. , Jablokoff H. , Hentschel M. , Gewald K. 
Published: December 2004

2‐Arylamino‐thiophene‐3‐carboxylic Acid DerivativesThe title compounds 3 are synthesized by reaction of 2‐amino‐thiophene‐3‐carboxylic acid derivatives 1 with anilines. The nucleophilic 5‐position in 3 allowed the synthesis of 5‐aryliden‐Δ3‐thiolen‐2‐one‐imines 5, 6 and the oxidative coupling to yield the azo compound 7. 1‐Aryl‐thieno‐[2,3‐d]pyrimid‐4‐ones 9, the thieno[2,3‐b]chinolin‐4‐one 10 and the 4‐chloro thieno[2,3‐b]chinolines 10, 11 can be obtained from 3.
Prostaglandins and prostaglandin intermediates. XV. Synthesis of 4‐Oxo Carboxylic Acids and γ‐Lactones by oxidative cleavage of homoallyl and homopropargyl ketones or alcohols
Authors: Schick H. , Welzel H.‐P. , Schwarz S. , Truckenbrodt G. 
Published: December 2004

AbstractA convenient method to convert homoallyl or homopropargyl ketones or alcohols into 4‐oxo carboxylic acids or γ‐lactones is the oxidative cleavage of the multiple bond with potassium permanganate in diluted sulfuric acid. This is exemplified by the preparation of intermediates for the synthesis of 8‐methylprostaglandin C2. The oxidation of the allylic compounds with permanganate is compared with the oxidative cleavage by ozone/hydrogen peroxide, ozone/chromic acid or sodium periodate/potassium permanganate.
Photochemie diarylsubstituierter 2H‐Tetrazole. II. Zum Einfluß der Substituenten auf die Absorptionseigenschaften diarylsubstituierter Nitrilimine
Authors: Csongár Ch. , Leihkauf P. , Lohse V. , Tomaschewski G. 
Published: December 2004

Photochemistry of Diarylsubstituted 2H‐Tetrazoles. II. The Influence of the Substituents on the Absorption Properties of Diarylsubstituted NitriliminesIrradation of 2,5‐diaryl‐2H‐tetrazoles in an EPA‐glass (ether: i‐pentan: ethanol=5:5:2) or in an i‐pentan glass at 77‐80 K with UV‐light of wavelength 290 nm yields diarylnitrilimines by the extrusion of nitrogen. The photoreactions investigated show spectroscopic unity. 22 diarylnitrilimines are included in the discussion with regards to the influence of substituents on the absorption maxima. The influence of substituents is interpreted by a LFE‐relationship. An intramolecular charge transfer as the reason for the relatively strong dependence of ν‐values on substituents is discussed.
Zur Herstellung von 1,3,4‐ Oxadiazol‐2‐carbonsäurederivaten
Authors: Dost J. , Heschel M. , Stein J. 
Published: December 2004

Preparation of 1,3,4,‐Oxadiazol‐2‐carboxylic Acid DerivativesThe synthesis of 5‐substituted‐1,2,4‐oxadiazol‐2‐carboxylic acid derivatives 3a‐g and 4a‐g by cyclodehydratation of diacylhydrazines 1a‐g and 2a‐g are described. Further derivatives 6 to 9 are obtained from 1,3,4‐oxadiazol‐2‐carboxethyl esters 3.
Elektrochemische Reduktion von Trichloracetaldehyd‐Olefin‐Additionsprodukten
Authors: Voigtländer R. , Matschiner H. , Krzeminski Chr. , Biering H. 
Published: December 2004

Electrochemical Reduction of Trichloroacetaldehyde‐Olefin‐Addition‐ProductsTrichloroacetaldehyde reacts with different olefins forming addition products. In most cases this reaction results in 1, 1, 1‐trichloro‐2‐hydroxy compounds (2a–d). But also a different route of reaction is possible. Thus 2, 3‐dimethylbut‐1‐ene (1e) forms 4‐trichloro‐1, 1, 2‐tetrahydroxy‐furane (2e) and cyclohexene (1f) forms 3‐trichloromethyl‐2‐oxabicyclo‐2, 2, 2‐octane (2f).All addition products are suitable starting materials for electrochemical conversions. In acidic electrolytes, on lead cathodes the electrochemical reduction results in a simultaneous cleavage of a CCl and a CO bond to form the CHCCl2‐group (3a‐f). In neutral electrolytes, on mercury cathodes, however, a reductive conversion of a CCl3 – group to a CHCl2‐group takes place (4c, 4f).
Untersuchungen zur Spin‐Trapping‐Kinetik in Systemen von Radikalen unterschiedlicher Reaktivität. Die Photolyse von α‐Phenylbenzoin in Gegenwart von Benzyliden‐tert.‐butylamin‐N‐oxid
Authors: Baumann H. , Timpe H.‐J. , Zubarev V. E. , Fok N. V. , Mel'nikov M. Y. , Raskasovskij Y. W. 
Published: December 2004

Investigations on Spin‐Trapping Kineties in Radical Systems with Different Reactivity. Photolyses of α‐Phenylbenzoine in the Presence of Benzylideneter. ‐butylamine N‐oxideAs a model system to study the spin‐trapping kinetics of systems forming two radicals of different reactivity α‐phenylbenzoine (PhB) was chosen. The photolysis of PhB forms benzoyl (B·) and diphenylketylradikals (K·), respectively, which can be trapped by benzylidene‐tert‐butyl‐amine N‐oxide (PBN), as a spin trap. The rate constants of radical addition to PBN and their reactions with the spin adducts were determined by means of flash photolysis and kinetic calculations of the PBN concentration dependence. For B· and K· addtion rate constants to PBN of k1 = 8,1 × 105 M−1s−1, and k2 = 5,8 · 104 M−1s−1, respectively, were found. The rate constants for the reactions of B· and K· with the spin adducts are in the order of 109…1010 M−1s−1.
Lichtabsorption und Substituenteneffekte bei Stilben‐4‐diazoniumionen
Authors: Walkow F. , Epperlein J. , Mustroph H. 
Published: December 2004

Light Absorption and Substituent Effects of Stibene‐4‐diazonium IonsSubstituent effects on ṽmax‐values of 31 stilbene‐4‐diazonium ions are studied. With increasing donor strength of a substituent in 4′‐position the long wave absorption band of stibene‐4‐diazonium ions shifts from the ultraviolet to the red region of the spectrum. The particular deep colour of diazonium compounds may be described by the very high σp‐Hammett‐constant of the diazonium group. The substituent effects found characterize stilbene diazonium ions as typical donor‐acceptor chromogenes.
Electronic Structure and Free‐Energy Relationships for Some 4′‐Substituted 4‐Dimethylamino trans‐Stilbenes by U.V. Photoelectron Spectroscopy
Authors: Cauletti C. , Furlani C. , Palma A. , Plancastelli M. N. , Schleinitz K. D. , Gloyna D. 
Published: December 2004

AbstractA Series of 4′‐subsituted 4‐dimethylamino trans‐stilbenes 1‐5 was investigated by UPS, in connection with conjugated donor‐acceptor substituted double bond photochemistry. The measured and assigned spectra indicate a high sensitivity, depending on the changed electronic structure by 4′‐substituents of compounds 1‐5. Correlation of ionization energies in LFE‐relationship with Hammett's σp‐values and other ground state data was proved, demonstrating UPS a powerful tool for substituent effect studies in conjugated double bond systems.
s‐Triazolo[4,3‐a][1,3]diazacycloalkanes. I Synthesis and Reactions of 3‐Oxo‐2,3,5,6,7,8‐hexahydro‐s‐triazolo‐[4,3‐a]pyrimidine
Authors: Krȩżel Izabella 
Published: December 2004

Abstract3‐Oxo‐2,3,5,6,7,8‐hexahydro‐s‐triazolo[4,3‐a]pyrimidine (5) was synthesized and its reactivity towards acylating reagents was examined. The assignment of tautomeric structures based on n.m.r. spectral data is discussed.
Pyryliumverbindungen. 31 [1]. Reaktion 3‐alkylsubstituierter 2,4,6‐Triaryl‐pyryliumsalze mit 1,3‐Diketonaten: Ein Weg zur Darstellung 3‐acylsubstituierter Benzophenone
Authors: Zimmermann Thomas , Fischer Gerhard W. 
Published: December 2004

Pyrylium Compounds. 31. Reaction of 3‐Alkyl‐2,4,6‐triarylpyrylium Salts with 1,3‐Diketonates: A Method for the Preparation of 3‐Acylsubstituted BenzophenonesReaction of 3‐alkyl‐2,4,6‐triarylpyrylium salts with 1,3‐diketones in the presence of one equivalent of triethylamine or potassium tert‐butoxide does not lead — as originally suspected — to the primary adducts of 2H‐pyran structure 6, but to the open‐chain valence isomers 7. Treatment of the latter with one equivalent of tert‐butoxide in tert‐butyl alcohol gives the same 3‐alkyl‐2,4,6‐triarylacetophenones 9 which are obtained directly from 5, 1,3‐diketones and two equivalents of potassium tert‐butoxide. However, on treating 7 with aqueous ethanolic sodium hydroxide 3‐acylsubstituted benzophenones 10 are formed in good yields. The reaction sequence 5→7→10 can also be performed through a one‐pot‐procedure. — The i.r., u.v., n.m.r. and mass spectroscopic data of the novel products 7, 9, and 10 are reported.
β‐Fur‐2‐yl‐α‐halogenacrylonitrile. V [1] Darstellung von β‐(5‐Nitro‐fur‐2‐yl)‐α‐azidoacrylonitril und β‐(5‐Nitro‐fur‐2‐yl)‐α‐aminoacrylonitril
Authors: Jähnisch K. , Gründemann E. 
Published: December 2004

β‐Fur‐2‐yl‐α‐halogenacrylonitriles. V. Preparation of β‐(5‐Nitro‐fur‐2‐yl)‐α‐azidoacrylonitrile and β‐(5‐Nitro‐fur‐2‐yl)‐α‐aminoacrylonitrileβ‐(5‐Nitro‐fur‐2‐yl)‐α‐chloroacrylonitrile (1) reacts with sodium azide to yield β‐(5‐nitro‐fur‐2‐yl)‐α‐azidoacrylonitrile (2). By Staudinger‐reaction β‐(5‐nitro‐fur‐2‐yl)‐α‐aminoacrylonitrile (5) is formed. The 1H‐ and 13C‐n.m.r. spectra of E/Z isomers are discussed.
Kinetic Modelling of the Oxidation of Medium Paraffins further evidence for the importance of bifunctional intermediates
Authors: Engelmann Eleonore , Just Gerhard , Pritzkow Wilhelm , Rudolf Matthias , Spindler Gerald , Tien Tieu Dung , Voerckel Volkmar , Wittekind Volker 
Published: December 2004

AbstractBy computer simulation of the dependencies of the mole numbers of the ketones and alcohols derived from the starting paraffin, of the acids and esters, and in some cases also of the lower alkan‐2‐ones on the paraffin conversion relative rate constants were determined on the basis of a plausible kinetic model of the paraffin oxidation. The data obtained show that about 67% of the oxidation proceeds via bifunctional primary products. With the aid of the relative rate constants determined a good simulation of the experimental mole number‐conversion curves is possible.
α‐Aminoketone – Ein Beitrag zur Synthese optisch aktiver Derivate von Aminosäuren und Peptiden
Authors: Fittkau Siegfried , Jahreis Günther , Peters Klaus , Baláspiri Lajos 
Published: December 2004

α‐Amino Ketones – A Contribution to the Synthesis of Optically Active Derivatives of Amino Acids and PeptidesThe synthesis of N‐Z‐protected methyl ketonesDie Nomenklatur der Ketonderivate von Aminosäuren und Peptiden entspricht den IUPACIUB Nomenclature Recommendations 1983, Eur. J. Biochem. 138 (1984) 9. Um die Beziehung zu den Aminosäuren herzustellen, wird für Aminoaceton die Bezeichnung Glycylmethan GlyCH3 benutzt.Weitere verwendete Abkürzungen: Z‐ = Benzyloxycarbonyl‐, E = Ether, PE = Petrolether, EE = Essigsäureethylester, CABE = Chlorameisensäure‐i‐butylester, TEA = Triethylamin, DMAP = 4‐Dimethyl‐aminopyridin, HMDS = Hexamethyldisiloxan, TMS = Tetramethylsilan, TRH = Thyreotropin Releasing Hormon, MSH‐RIF (MIF) = MSH‐Release‐Inhibiting‐Factor (MSH = Melanocyten stimulierendes Hormon).

from amino acids via the chloromethyl ketones and dehalogenation of the latter with zinc in glacial acetic acid is described. Deprotection of the methyl ketones results in the formation of hydrohalogenides of the α‐aminoalkyl methyl ketones further converted to N‐acylated peptide ketones as analogs of peptide hormones or as competitively acting substrate analogs of proteolytic enzymes. Aminoacetone is conveniently prepared as well as methyl‐pyrrolidyl ketone and methyl‐piperidyl ketone.