bluuebunny/crossref_metadata_2025 huggingface dataset:
O.N‐bis(diphenylphosphino) derivatives of chiral trans‐ and cis‐2‐aminocyclohexanols: Synthesis and enantioselective behaviour as ligands in Rh‐based homogeneous hydrogenation catalysts
Authors: Pracejus H. , Pracejus G. , Costisella B.
Published: December 2004

trans‐ and cis‐2‐Methylamino cyclohexanols (MAC) were prepared in enantiomerically pure forms and transformed into O.N‐bis(diphenylphosphino) derivatives (“PONP”). An analogous trans‐1 R; 2 R‐aminocyclohexanol PONP could only be isolated in an impure form, whereas the attempted synthesis of PONP's of diastereoisomeric trans‐2‐(N‐α‐phenylethylamino)‐cyclohexanols failed. Cationic Rh(I)‐chelates of the new PONP's catalyzed the enantioselective hydrogenation of dehydro‐α‐acylamino acids with ≦97% ee. A comparison of the enantiodiscriminating properties of the MAC‐PONP's with structurally related chiral ligands leads to surprising conclusions.
Zur Wechselwirkung von Donoren mit Diethylaluminiumchlorid. IV. 13C‐NMR‐Untersuchungen zum Ausmaß der Komplexbildung
Authors: Schütz H. , Hallpap P. , Hartung H. , Stadermann D. , Heublein G. , Denissov V. M. , Kolzov A. I.
Published: December 2004

The Interaction of Donors with Diethyl Aluminium Chloride. IV. 13C‐N.M.R.‐Investigations on the Degree of Complex Formation

Et2AlCl has some importance for the initiation of cationic polymerizations where its activity can be influenced by the addition of donor compounds. To enlight the elementary processes quantitative 13C‐n.m.r. spectroscopic investigations of the model systems Et2AlCl/pyridine and piperidine, respectively, were carried out. Detailed information are given with regard to the molar ratios of acceptor and donors. The formation of an ionic intermediate complex was observed. The degree of complex formation is higher for piperidine than for pyridine. In the case of pyridine a 1:1 complex is formed. With piperidine a complexation with higher coordination must be assumed.
Studies on the oxidative cleavage of the CC triple bond during the Autoxidation of Acetylenic Hydrocarbons 1. Evidence for α‐dicarbonyl compounds as intermediates
Authors: Rao T. S. S. , Pritzkow W.
Published: December 2004

Examination of oxidation mixtures of 1‐phenylprop‐1‐yne, 1‐phenylbut‐1‐yne and 1‐phenyl‐3‐methylbut‐1‐yne revealed the presence of hitherto not reported interesting products, especially the α‐dicarbonyl compounds 1‐phenylpropane‐1,2‐dione, 1‐phenylbutane‐1,2‐dione and 1‐phenyl‐3‐methylbutane‐1,2‐dione respectively in minor quantities. Some other typical products like benzil, benzoic anhydride and phenyl benzoate were also characterized. Although the oxidation of diphenylacetylene is very slow, benzil could be found as the main detectable product along with traces of benzoic acid. The α‐diketones corresponding to the 1‐phenylalk‐1‐ynes were oxidized at 110°C. In each case benzoic acid and the lower carboxylic acids as in the case of the autoxidation of the corresponding acetylenes were obtained. Benzil, benzoic anhydride and phenyl benzoate were also characterized in all the cases. Therefore, α‐diketones are considered as intermediates responsible for the formation of the oxidative cleavage products of the CC triple bond.
Pyryliumverbindungen. 36. Substituierte Benzoesäureester aus 2,4,6‐Triaryl‐pyryliumsalzen und α‐Ketocarbonsäureestern
Authors: Zimmermann Thomas , Fischer Gerhard W.
Published: December 2004

Pyrylium Compounds. 36. Substituted Benzoic Acid Esters from 2,4,6‐Triarylpyrylium Salts and α‐Ketocarboxylic Acid Esters

2,4,6‐Triarylpyrylium salts 1 react with α‐ketocarboxylic acid esters 2 in the presence of two equivalents of an appropriate condensing agent (e.g. dialkylamine salts of weak acids, triethylamine/acetic acid, or sodium acetate) to give 2‐aroyl‐3,5‐diarylbenzoic acid esters 3. However, using only one equivalent of the condensing agent, the formation of 3,5‐diarylbenzoic acid esters 5 predominates. Alkaline saponification of the new esters 3 and 5 yields the corresponding substituted benzoic acids 4 and 6, respectively. – I.r., u.v., n.m.r. and mass spectroscopic data of the novel products 3–6 are reported.
Ketene‐S,N‐acetals as synthons for heterocycles New Synthesis of Pyrimidinones
Authors: Gelbin Michael , Martin Dieter
Published: December 2004

Ketene‐S,N‐acetals of type 1, 2 reacted with isocyanates to 5‐cyano‐uracils 3 and 5‐cyano‐pyrimidin‐2‐ones 4, 5. Reaction of these with N nucleophiles was investigated furnishing 6‐amino‐pyrimidinones 6 as well as condensed pyrimidin‐2‐ones 7‐‐10 and 13. Cyanic acid esters gave 5‐cyano‐pyrimidin‐4‐ones 16. Behavior of 16 toward nucleophiles is reported.
Reaktion von O,O‐Dimethylthiophosphorsäureamid mit Chloral
Authors: Teichmann H. , Schnell M.
Published: December 2004

Reaction of O, O‐Dimethyl Phosphoramidothioate with Chloral

The system O,O‐dimethyl phosphoramidothioate (1)/chloral was investigated at room temperature. Two competing reactions occur: (A) formation of the 1:1 adduct 2, and (B) sulfur/oxygen exchange yielding the oxo compound 3, which subsequently forms a chloral adduct 4.
Push‐pull‐Butadiene. VIII. Reaktionen von substituierten Penta‐1,4‐dien‐1,1,5,5‐tetracarbonitrilen
Authors: Peseke K. , Michalik M. , Schönhusen U. , Quincoces J. , Radeglia R.
Published: December 2004

Push‐pull‐Butadienes. VIII. Reactions of Substituted 1,4‐Pentadiene‐1,1,5,5‐tetracarbonitriles

4‐Aryl‐2‐methylthio‐1,4‐pentadiene‐1,1,5,5‐tetracarbonitriles 1 react with bromine to give the nicotinonitriles 2. Compounds 2 and hydrazine hydrate yield the pyrazolo[3,4‐b]‐pyridines 7. Bis(methylthio)nicotinonitriles 9 are prepared by the treating of 2 with methanethiol in an alkaline solution. Compounds 1 can be converted with hydrobromic acid or hydrochloric acid to the nicotinonitriles 2a‐‐c and 2d‐‐f, respectively.
Protonierung und Solvatation schwacher organischer Basen. III. UV‐ und 1H‐NMR‐spektroskopische Untersuchungen zur Basizität von 1,3‐Diketonen
Authors: Kröger C.‐F. , Freiberg W. , Hauer U.
Published: December 2004

Protonation and Solvation of Weak Organic Bases. III. U.V. and 1H‐N.M.R. Spectroscopic Investigations of the Basicity of 1,3‐Diketones

By 1H‐n.m.r. spectroscopy it is possible to determine separately the basicity parameters (H0)1/2 or pK and the solvation paramters m, ϕ or m* for the keto and the enol form of acetylacetone. By u.v. spectroscopy only brutto parameters of the equilibrium mixture for acetyl‐ and benzoylacetone as for dibenzoylmethane are available.
Kristallinflüssige trans‐4‐(ω‐Cyanalkyl)cyclohexylester und 4‐(ω‐Cyanalkyl)phenylester
Authors: Deutscher H.‐J. , Krieg R. , Frach R. , Kresse H. , Zaschke H.
Published: December 2004

Liquid Crystalline trans‐4‐(ω‐Cyanalkyl)cyclohexylester and 4‐(ω‐Cyanalkyl)phenylesters

The synthesis of the title esters 1 and 2a–e (n = 0 – 3) and their mesomorphic properties are described. When the alkyl‐spacer n between the polar CN‐group and the cyclohexane ring of cyanalkyl‐cyclohexylesters 1 is increased the difference of the clearing points between the phenylesters 2 and the cyclohexylesters 1 decreases to nearly zero. The reason of higher clearing temperatures of 2 is a dynamic conformational effect of ring inversion of cyclohexane in the ester 1 with two polar substituents at the ring.
Construction of the Alkyl Side Chain of 11‐Deoxyprostaglandins Using the Aldol Reaction of Substituted Cyclopentane Carbaldehydes with Heptan‐2‐one
Authors: Mahrwald Rainer , Schick Hans , Vasil'eva L. L. , Pivnitsky K. K.
Published: December 2004

The aldol reaction of the substituted cyclopentane carbaldehydes 1 with heptan‐2‐one was demonstrated to offer an effective alternative to the carbonyl olefinations generally used for the build‐up of the (E)‐3‐oxooct‐1‐enyl side chain of 11‐deoxyprostaglandins. In this case dimethyl 2‐oxoheptylphosphonate can be substituted advantageously by the cheaper heptan‐2‐one as side chain precursor.
Kristallin‐flüssige Heterocycloalkane. III. Synthese und kristallin‐flüssiges Verhalten substituierter 1,3‐Dioxadecaline
Authors: Tschierske C. , Zaschke H.
Published: December 2004

Liquid‐Crystalline Heterocycloalkanes. III. Synthesis and Liquid‐Crystalline Properties of Substituted 1,3‐Dioxadecalines

Liquid‐crystalline 2‐substituted and 2,6‐disubstituted 1,3‐dioxadecalines (4—6) were synthesized by acid‐catalyzed acetalization of trans‐2‐hydroxymethylcyclohexanol (1) or trans‐4‐alkyl‐trans‐2‐hydroxymethylcyclohexanoles (2) with aldehydes 3 whereby the desired transisomers were formed only. The syntheses of the various aldehydes are also described.

Special attention is drawn on the evolution of mesogenic properties of the titlecompounds 4—6 in comparison with known decalines and 1,3‐dioxanes.

It was found that the clearing temperatures of the synthesized 1,3‐dioxadecalines are always lower than those of the corresponding decaline derivatives, due to the deformation of the decalineringsystem by the introduction of two oxygen‐atoms. The comparison of 1,3‐dioxanes and 1,3‐dioxadecalines shows that the dioxadecaline ringsystem tends to suppress smectic mesophases in favour of nematics. A first example of a liquid crystalline cis‐fused 1,3‐dioxadecaline (8) is described, too.
Nitration of the Acetanilide‐type Compounds
Authors: Daszkiewicz Zdzislaw , Kyziol Janusz B.
Published: December 2004

Some aromatic compounds containing the imino group (NH) were nitrated in acetic acid or anhydride, and the ortho/para ratios were measured. N‐Methyl derivatives of the aforementioned compounds are much less reactive when nitrated under comparable conditions and give significantly lower o/p ratios. These results along with the literature data support the hypothesis that the acetanilide‐type compounds are nitrated via N‐nitro intermediates.
Nitriles in heterocyclic synthesis: A new approach for the Synthesis of Thiazole derivatives
Authors: Ibrahim N. S. , Mohareb R. M. , Elnagdi M. H.
Published: December 2004

The reaction of 4‐bromo‐3‐oxo‐butyranilide (1) with KSCN afforded the thiocyanato derivative 2. 2‐Dicyanomethylthiazol‐4‐yl‐acetanilide (3) was synthesised by reaction of 2 with malononitrile. A variety of substituted thiazol‐2‐yl malononitriles were prepared by reaction of 3 with hydroxylamine hydrochloride, phenylhydrazine and cinnamonitrile derivatives. The structure assignments of the new compounds are based mainly on 13C and 1H‐n.m.r. spectroscopic data.
Säurestärke und Komplexbildung von Curcuminoiden
Authors: Arrieta A. , Dietze F. , Mann G. , Beyer L. , Hartung J.
Published: December 2004

Acidity and Complex Formation of Curcuminoids

The stoichiometric acid dissociation constants of curcumin 1a and derivatives as well as the stoichiometric stability constants of the Cu(II)‐ and Ni(II)‐complexes of these substances have been determined by pH‐potentiometric titrations in dioxane‐water mixture.

The influence of different substituents on the pKa‐values and the stability constants is discussed. The complexing properties of the COCH2CO structural element of the ligands are not significantly changed when the phenyl group is substituted by the styryl group. Solid CuL2‐complexes have been characterized. The coordination of the ester group in the tricarbonyl ligand systems 4 was excluded by i.r. spectroscopy.
O‐Methylierung von tert.‐Alkylbrenzcatecholen. Analytische Methode zur Bestimmung der Zusammensetzung von Produktgemischen und Synthese‐variante zur Herstellung von 4‐tert‐Alkylveratrolen
Authors: Beger J. , Meerbote M.
Published: December 2004

O‐Methylation of tert‐Alkylpyrocatecholes. Analytical Method for Determination of the Content of Product Mixtures and Way for Preparation of 4‐tert‐Alkylveratroles

The O‐methylation of tert‐alkylpyrocatecholes with dimethylsulfate leads to a mixture of substituted guaiacoles 6/7, 9/10 and veratroles 5, 6 which are separated by gas/liquied‐chromatography for analytical purposes. It is also possible to prepare 4‐tert‐alkylsubstituted veratroles 5 with good yields in this way.

On the other hand, the alkylation of veratrole was only successful with lower tert‐alkanols or alkenes. Long‐chained tert‐alkanols fail in this reaction.

The analytical and spectroscopical data of some new 4‐tert‐alkylveratroles 5a—g are given.
Azocoupling of Quaternary 1,2,4‐Triazolium Salts to form 5‐p‐N,N‐dimethylaminophenylazo‐1,2,4‐triazolium salts
Authors: Becker H. G. O. , Hoffmann Gerda , Gwan Kim Mun , Knüpfer L.
Published: December 2004

Quaternary 1,2,4‐triazolium salts 1 couple easily with p‐N,N‐dimethylamino‐benzenediazonium salts to form azodyes 3 (5‐N,N‐dimethylaminophenylazo‐1,2,4‐triazolium salts), preferably under solid‐liquid phase transfer conditions using chloroform or methylene chloride and triethylamine or DABCO.

Zwitterionic 1,2,4‐triazolium salts anhydro mercapto hydroxide, anhydro hydroxy hydroxide, and anhydro anilido hydroxide („nitron”︁) couple as well.

The azodyes — as also well known from industrially used types — absorb in the region of 500 nm and have high extinction coefficients.

Substituents in 1‐, 3‐ or 4‐position of the triazolium ring exert no clear substituent effects.

The quaternary 1,2,4‐triazolium salts were synthesized according to standard procedures.
Synthese heterocyclisch substituierter 4‐Piperidinyl‐1,4‐dihydropyridine durch Ringschlußreaktion an einer N‐Acylthioamid‐ und N‐Acylisothioamid‐Seitenkette
Authors: Pragst F. , Liebscher J. , Boche E. , Köppel H.
Published: December 2004

Synthesis of Heterocyclically Substituted‐4‐Piperidinyl‐1,4‐dihydropyridines by Ring Closure Reactions at a N‐Acylthioamide‐ or at a N‐Acylisothioamide‐Side‐Group

A series of 4‐(2′‐methylenepiperidin‐4′‐yl)‐1,4‐dihydropyridines [5–7 and 9–11] with a heterocyclic substituent at the methylene group is prepared by reaction of the nonsubstituted compound 1 with benzoylisothiocyanate or ethoxycarbonylisothiocyanate to the N‐benzoylthioamide 2 or the N‐ethoxycarbonylthioamide 3, transformation of 2 into the isothioamide 4 by S‐methylation, and subsequent ring closure of 2, 3 or 4 with hydrazine, methylhydrazine, phenylhydrazine, 1,2‐diaminoethane, 1,2‐ and 1,3‐diaminopropane, o‐diaminobenzene and o‐aminophenol.
Direct Synthesis of Pyrazoles via reaction of C‐ethoxycarbonyl‐N‐arylnitrilimines with benzalmalononitriles and some α‐cyanocinnamic acid derivatives
Authors: Hassaneen Hamdi M. , Algharib Mohammed S. , Farag Ahmed M. , Shawali Ahmed S.
Published: December 2004

Reaction of C‐ethoxycarbonyl‐N‐arylnitrilimines (2a–d) with α, β‐disubstituted acrylonitriles (3a–f) in refluxing benzene affords the corresponding substituted pyrazoles 5a–f and 6a–c respectively in good yield. However, reaction of 2a–e with 3g gives the 2‐pyrazoline derivatives 7a–d. The assigned structures for the products 5–7 were confirmed by their spectra (i.r., 1H‐n.m.r.) and elemental analyses. Also the structures of the pyrazoles 5 were substantiated by comparison with their regioisomeres 8.
Heterocyclisch substitutierte Arendiazoniumsalze mit erweiterter spektraler Empfindlichkeit ‐ Teil I: Monomethine und Azamethine
Authors: Fanghänel E. , Kühnemund K.‐H. , Richter A. M.
Published: December 2004

Heterocyclic Substituted Arendiazonium Salts with a Long‐wave‐length Range of Sensitivity — Part I: Monomethins and Azamethins

Two new types of arendiazonium salts have been synthesized. In these compounds a heterocycliden ring is bridged through a methine group (8a–o) or a nitrogen (11a–c) with the 4‐position of a benzene diazonium group.

Both types show sensitivity towards normal day‐light, their long wave‐length absorption band vary from 430 nm up to 590 nm, depending on the donor strength of the heterocycliden ring and the nature of the bridging group.

The thermostability, the quantum yields of photochemical dediazonation and the coupling behaviour of the diazonium salts are investigated, in order to evaluate their potential applicability in a commercial diazotype system.
A novel synthesis of 1,3 Thiazetidine‐2‐one and 1,3‐Oxazine‐2‐one Derivatives
Authors: Żankowska‐Jasińska W. , Burgiel M. , Danel A. , Sygula A.
Published: December 2004

In the reactions of acetylthioacetanilides (1a–c) and diacetylthioacetanilides (3a–f) with phosgene 1,3‐thiazetidine‐2‐one (2a–c) and 1,3‐oxazine‐2‐one (5a–f) were obtained respectively. The structures of new compounds were elucidated by elemental analyses, i.r., 1H‐n.m.r., m.s., for 1d–f by 19F‐n.m.r. and for 2a and 5a by 13C‐n.m.r. spectral data.
Kinetische Untersuchungen zur Aminolysereaktion von Dithiophosphorsäureestern mit Monomethylamin in binären Methanol/Wasser‐Mischungen
Authors: Füllbier B. , Klemmer K. , Wettengel A. , Haberland D.
Published: December 2004

Kinetic Investigations on the Aminolysis Reaction of the Dithiophosphoric Esters with Monomethylamine in Binary Methanol/Water‐Mixtures

The influence of the solvent polarity on the aminolysis reaction between 0,0‐dimethyl‐S‐(methoxycarbonylmethyl)‐dithiophosphoricacidester (1) and monomethylamine, which is the main reaction of the “Dimethoate” synthesis, is investigated. The observed effects are compared with those of the alkylation of these esters by monomethylamine. Both reactions show a similar dependence on the solvent polarity.
Zum Fluoreszenzverhalten der isomeren Bis(acridiziniumyl)‐Dikationen
Authors: Helm S. , Bendig J. , Kreysig D.
Published: December 2004

Fluorescence Behaviour of the Isomeric Bis(acridizinium‐yl)Dications

The fluorescence behaviour of the isomeric bis(acridizinium‐yl)dications is characterized by anomalies of the spectra. At room temperature the emission spectra of the 7,7′‐ and the 8,8′‐isomer show the typical characteristics of a TICT fluorescence band, they are strong red shifted and structureless. The emission wavelength shows the typical dependence on the solvent. At 77 K the expected spectra are obtained.

The room temperature spectrum of the 9,9′‐isomer is the result of a plain emitting molecular state. The emission wavelength is only slightly red shifted. The solvent influences the molecular dynamics in the excited state.

The differences in the deactivation behaviour of the isomers are caused by different energies of the Frank Condon singlet states.
15N‐ and 13C‐N.M.R. Study of Azo‐hydrazone Tautomerism of 3‐methyl‐1‐phenylpyrazole‐4,5‐dione 4‐phenylhydrazone in dimethyl sulphoxide and pyridine
Authors: Lyčka Antonín , Mustroph Heinz
Published: December 2004

The 15N‐ and 13C chemical shifts and 1J(15Nα15Nβ) coupling constants of 3‐methyl‐1‐phenylpyrazole‐4,5‐dione 4‐phenylhydrazone (1) were measured in dimethyl sulphoxide and pyridine solutions. It was found that compound 1 exists fully in its hydrazone form in these two solvents, contrary to the previously published data which propose equilibrium mixture of the hydrazono and azo forms.
Besonderheiten des Pyrolyseverhaltens von Isoalkylaromaten
Authors: Bach G. , Ondruschka B. , Zychlinski W. , Shevelkova L. V. , Sokolovskaja V. G.
Published: December 2004

Special Features in Pyrolysis Behaviour of Isoalkylaromatics

The pyrolysis of cumene, sec. butyl‐ and tert. butylbenzene proceeds in a laboratory scale quartz vessel in the temperature range 600–750°C. Conversion occurs mainly via a radical‐chain mechanism in the side chain in proportions, determined by the dissociation energies of the CC‐ and CH‐bonds. Dealkylation was observed in greater amounts than for n‐alkylbenzenes. It is interpreted by H‐atom addition to the aromatic nucleus, followed by β‐scission to benzene and isoalkenes. It was be shown, that H‐atoms are formed by unusual reactions such as neophyl rearrangement and homolytic rupture of CC‐bonds in the side chain.
Zur σ‐Akzeptorstärke von starken organischen Elektronenakzeptoren
Authors: Spange S. , Heublein G.
Published: December 2004

On the σ‐Acceptor Strength of Strong Organic Electron Acceptors

Acceptor numbers (AN) according to GUTMANN of various strong organic electron acceptors, such as TCNE, chloranile, C7H7⊕ or triphenylmethylium salts, have been obtained by means of complexation with Fe(phen)2(CN)2 in 1,2‐dichloro‐ethane and nitromethane. The AN of organic electron acceptors reflect the capability of a weak coordinative electrophilic attack upon nucleophilic compounds. Based on these results the influence of solvents upon CT‐energy (ṽCT) in weak π‐electron‐donor‐acceptor complexes is discussed. The blue shift of ṽCT depends on the donicity (D) of the solvent, which leads to linear correlations of ṽCT versus parameters of donicity. The sensitivity of solvatochromy depends on the AN of the acceptor. On the variation of the bπ‐donor the sensitivity of solvatochromy in relation to the quotient dṽCT/dD is influenced. With the help of polarographic results can be demonstrated that the influence of solvents on ṽCT remarkably depends on the specific solvation in the ground state of the electron acceptor.
Thiatriazole. V. Zur Reaktion von Isothiocyanaten mit 1,2,3,4‐Thiatriazolderivaten
Authors: Graubaum H.
Published: December 2004

Thiatriazoles V. On the Reaction of Isothiocyanates with Thiatriazole Derivatives

The reaction of 1,2,3,4‐thiatriazoles with alkyl and aryl isothiocyanate proceeded differently. Methylisothiocyanate furnished a 2:1 product with 5‐amino‐1,2,3,4‐thiatriazole. Arylisothiocyanates reacted under the same conditions to the known thiapentalenes 6. 5‐Alkyl‐ and 5‐arylamino‐1,2,3,4‐thiatriazoles gave 5‐substituted 1,2,4‐thiadiazol‐3‐thions 8. Similar the hydrazones of 1,2,3,4‐thiatriazole reacted with isothiocyanate to form the hydrazones of 1,2,4‐thiadiazole‐3‐thione 10. 4‐Dimethylamino‐pyridine is a necessary catalyst for the selectivity of these reactions.
Cyclofunktionalisierung von 2‐Allyl‐phenolen mit Schwefelchloriden. III. 2‐Arylthiomethyl‐2,3‐dihydrofuro[3,2‐h]chinoline aus 7‐Allyl‐ bzw. 7‐Methallyl‐8‐hydroxychinolin und Aryl‐sulfenylchloriden
Authors: Meinhold H. , Mühlstädt M. , Muslih R. M.
Published: December 2004

Cyclofunctionalization of 2‐Allyl‐phenols with Sulfur Chlorides. III. 2‐Arylthiomethyl‐2,3‐dihydrofuro[3,2‐h] quinolins from 7‐Allyl‐ and 7‐Methallyl‐8‐hydroxyquinoline, respectively, and Arylsulfenyl Chlorides

Reactions of 7‐allyl‐ (3) and 7‐methallyl‐8‐hydroxyquinoline (4) with selected arylsulfenyl chlorides (5a–d) yield the products of cyclofunctionalization corresponding 2‐arylthiomethyl‐2,3‐dihydrofuro[3,2‐h]quinolins (6 and 7). The products are identified by 1H‐n.m.r.‐spectroscopy, mass spectrometry and microanalyses.
Flavyliumsalze als Sonden zur Charakterisierung anionischer Tensidlösungen
Authors: Fanghänel E. , Willscher S. , Ortmann W.
Published: December 2004

Flavylium Salts as Probes for the Characterization of Anionic Micelles

Flavylium salts are suitable probe molecules for the fluorimetric investigation of the critical micelle concentration (CMC); for the absorption‐spectroscopic investigation of the surface potential; and also the microacidity in the Stern‐layer of anionic micelles. The reaction rates of the hydrolytic cleavage of the 7‐hydroxy‐4′‐methoxyflavyliumion 1a and the equilibrium between 1a and the 2,4‐dihydroxy‐4′‐methoxychalcone 5a formed were studied in acidic water solutions and in micellar surfactant solutions. Both measurements resulted in comparable values of the microacidity on the surface of the sodium dodecylsulfate micelles (SDS). The calculated surface‐potential of SDS‐micelles corresponds to literature data.

The surface‐potentials of p‐dialkylbenzenesulfonate micelles (p‐DABS) depend on the structure of these surfactants in a characteristic manner.
Reactions with substituted acrylonitriles: A novel Synthesis of Polysubstituted Pyrimidines
Authors: El‐Sharabsy Salwa A. , Gawad Soad M. Abdel , Hussain Sohair M.
Published: December 2004

3‐Arylacrylonitrile‐2‐thiocarboxamides (1a–d) reacted with S‐methylisothiourea to give 4‐amino‐6‐aryl‐2‐methylmercaptopyrimidine‐5‐carbonitriles (3a–d). The products 3a–d were also obtained via the reaction of 3‐arylacrylonitrile‐2‐carbonitriles (4a–d) with S‐methylisothiourea. Compounds 4a–d reacted with thiourea and urea to yield 4‐amino‐6‐aryl‐2‐mercaptopyrimidine‐5‐carbonitriles (5a–d) and 2‐hydroxy derivatives (5e–h) respectively. Oxidation of 5a–d with hydrogen peroxide afforded 5e–h. 5a–h were readily alkylated with methyl iodide to give 3a–d.
Untersuchungen zur regioselektiven Halogenierung von 4‐Amino‐2‐iodmethyl‐6‐methyl‐pyrimidinen
Authors: Zeuner F. , Niclas H.‐J.
Published: December 2004

Studies on the Regioselective Halogenation of 4‐Amino‐2‐iodomethyl‐6‐methylpyrimidines

In the presence of oxidants, 4‐amino‐2‐iodomethyl‐6‐methylpyrimidines 2 undergo regioselective reactions in the positions 2 and/or 5. Thus, the reaction of 2a with hydrogen peroxide proceeds under dealkylation and iodination to give 4‐amino‐5‐iodo‐6‐methylpyrimidine 7. Depending on reaction temperature and molar ratios the reaction of 2a with bromine or chlorine leads to the corresponding 4‐amino‐5‐halogeno‐2‐halogenomethyl‐6‐methyl‐pyrimidines 2c, 9a and 9d. The 5‐substituted pyrimidines 2b, c afford the 2‐bromo (or chloro) methyl derivatives 9b, c.
Synthese und Strukturaufklärung von 19‐Nor‐pregnanderivaten mit stickstoffhaltigen Vierringen in 14,15‐Stellung
Authors: Ponsold K. , Prousa R. , Reck G.
Published: December 2004

Synthesis and Structural Elucidation of 19‐Nor‐pregnane Derivatives with Nitrogen‐Containing Four‐Membered Rings in 14,15‐Position

The introduction of a C2 side chain in the 17‐position of 3‐methoxy‐14β, 15β‐(3′,4′‐azetidine)‐estra‐1,3,5(10)‐trien‐17β‐ol (1) is described. Hydroboration of the 17‐ethylidene compound 4 gives a mixture of the 17αH and 17α‐pregnane derivatives 6 and 6a in 70% and 10% yields, respectively. Birch reaction of 6, followed by oxidation yields the 14β,15β‐(3′,4′‐azetidine)‐19‐nor‐pregn‐4‐ene‐3,20‐dione (12). The new compounds were characterized by 1H‐n.m.r. The structure of product 13 was determined by X‐ray crystallography.
Struktur‐Reaktivitäts‐Beziehungen bei koordinativ‐ungesättigten Chelatkomplexen. XI, Einfluß des Zentralatoms und der Ligandstruktur auf die Massenspektrometrische Fragmentierung von Chelatkomplexen makrocyclischer und offenkettiger Schiffscher Basen
Authors: Schade W. , Jäger E. G. , Müller K. , Seidel D.
Published: December 2004

Structure Reactivity Correlations on Coordinatively Unsaturated Metal Chelate Complexes. XI. Effect of the Central Atom and the Ligands on the Mass Spectrometric Fragmentation of Chelate Complexes with Macrocyclic and Open Chain Schiff Base Ligands

The influence of the central atom on the mass spectrometric fragmentation of the compounds 1–5 is compared. Whereas the ligands (Mt = 2H) show a strong fragmentation with a farreaching cleavage, the metal complexes with exception of Cu‐4 and Cu‐5 show always the molecular ion signal as the base peak. The main fragmentions [M‐C2H5O]⊕, [M‐2(C2H5O)]2⊕, [M‐C2H4]⊕., and [M‐C2H4CO2]⊕. may be related to the ‘cyclidene’ structures 6–7, the carboxylic acid 8, and its decarboxylation product 9. In the case of the copper chelates 1–4 the fragment [M‐C2H6O].⊕/2⊕ with one or two positive charges is dominating over the peak [M‐C2H5O]⊕. This may be due to the abstraction of one H from an ethylene (type 1, 2, 4) or a methyl (type 3) group with concomitant reduction to Cu(I) (10) or oxidation to Cu(III) (11).
Oxidative decomposition of oxirane and methyloxirane polyethers. II [1]. Autoxidation of Dipropylene Glycol Isomers
Authors: Janik R. , Gerhardt W.
Published: December 2004

The oxidative decomposition of two structural isomers of dipropylene glycol, i.e. 2,4‐dimethyl‐3‐oxapentandiol‐1,5 (1) and 4‐oxaheptandiol‐2,6 (2) was studied. The maximum rate of oxidation of glycol 1 was ca. 20 times lower than that of glycol 2. In the products of oxidation 15 different compounds were detected for the former glycol and 20 compounds for the latter. The products of decomposition were the mixtures of water and carboxy acid, acetal, alcohol, aldehyde, ketone, ester, unsaturated ether and hydroperoxy type of compounds of different structure. The mechanism of product formation is discussed.
Reduced Enzymic Control of Free Radical and electron transport reactions in the mitochondria of zajdela hepatoma ascitic cells: A model for the stepwise transformation of healthy to tumorous cells involving a progressive loss of antioxidant activity
Authors: Tkáč A. , Hanušovská‐Tkáčová E.
Published: December 2004

Differences in the radical chemistry of normal and tumorous rat liver cells were demonstrated using e.s.r. techniques. In healthy cells the one‐electron transfer from hemoproteins to peroxides and hydroperoxides is accompanied by radical formation and proceeds predominantly in the endoplasmatic reticulum. Their mitochondria are effectively shielded against autoxidation. The opposite is true for Zajdela hepatoma ascitic cells and mitochondria. Mitochondria isolated from this type of cancerous cell are sensitive targets for radical attack and irreversible oxidation of thier hemoproteins from the FeII to FeIII oxidative state. A probable location for electron leakage in cancerous rat liver cells, depleted of the enzyme Mn‐SOD, controlling the O level, and of catalase, controlling the H2O2 level, seems to be the ubisemiquinone‐cytochrome c component of the mitochondrial respiration redox chain, where the active center of cytochrome oxidase is blocked and so the controlled four‐electron transfer to molecular oxygen is prevented. A model is proposed to explain the stepwise transformation of a highly organized differentiated cell to an uncontrolled proliferating tumor cell. The transition is brought about by a progressive loss of protective capacity which allows transition metal coordinated radicals, carried by hemoproteins, to cross the nuclear membrane. Inside the nucleus decomplexation of the stabilized radicals will release damaging short‐lived radical species.
Calix[n]arene. III. Calix[n]arenderivate mit antioxidativen Wirkungen
Authors: Görmar Gerhard , Seiffarth Klaus , Wendt Dietmar , Burtzlaff Christa
Published: December 2004

Calix[n]arenes. III. Calix[n]aren Derivates with Antioxidation Effectivity

The new tert.‐butylcalix[n]arenes compounds 4 and 5 are synthesized by esterification with carboxylic acid chlorides of hindered phenolic derivatives.

These new calix[4]arenes connected with inhibitor groups act as antioxidants in tetraline and low density polyethylene (Mirathen Al 21 FAR). Compound 5 shows better antioxidative efficiency than tert.‐butylcalix[4]arene 1.
1,3,4‐Thiadiazole durch Umsetzung von Dithioestern mit Kohlensäurehydraziden
Authors: Thiel W. , Mayer R.
Published: December 2004

1,3,4‐Thiadiazoles by Reaction of Dithiocarboxylic Esters with Carbonic Hydrazides

1,1‐Dithiooxalic esters 1 and heteroaryl dithiocarboxylic esters 2 react with carbonic hydrazides yielding 1,3,4‐thiadiazoles. The 1‐thiooxamoyl semicarbazides 3 or 1‐heteroylthiocarbonyl semicarbazides 4, primarily formed by thioacylation of semicarbazide, where isolated. By cyclocondensation they yield 1,3,4‐thiadiazole‐2(3 H) ones 5, 6, or in the presence of acetic anhydride 3‐acetyl‐1,3,4‐thiadiazol‐2‐ones‐ 7, 8, respectively.

2‐Amino‐ or 2‐methylthio‐1,3,4‐thiadiazoles 11, 12 or 13, 14 are formed by reaction of the dithioesters 1, 2 with thiosemicarbazide or methyl dithiocarbazinate. By this way 1,3,4‐thiadiazoles with heteroaryl‐ or carbamoylresidues in position 5 where synthesized for the first time.
Prostaglandins and prostaglandin intermediates. 25. Synthesis of PGF2α Intermediates by addition of 1‐metalated hept‐1‐ynes to a substituted cyclopentanecarbaldehyde bearing already the complete carboxylic side chain
Authors: Mahrwald Rainer , Schick Hans , Vasil'eva Ludmila L. , Pivnitsky Kasimir K. , Weber Gisela , Schwarz Sigfrid
Published: December 2004

Starting with the racemic aldehyde 4, prepared from the tris(trimethylsilyl) ether 3, the possibility was demonstrated of converting a trimethylsilylated primary hydroxy group with high selectivity into an aldehyde group in the presence of two trimethylsilylated secondary hydroxy groups employing oxalyl chloride and dimethyl sulfoxide (Swern reagent) as oxidant. The alkynylation of this aldehyde with 1‐metalated hept‐1‐yne afforded a chromatographically separable mixture of two diastereomeric alcohols, both being suitable intermediates for the synthesis of PGF2α. The diastereofacial selectivity of the addition strongly depends on the metal employed. Hept‐1‐yn‐1‐yllithium afforded a 67:33 mixture of (13 R*)‐ and (13 S*)‐alcohol, hept‐1‐yn‐1‐yltriisopropoxytitanium, however, a 30:70 mixture.
Studies of a Possible Mechanism of Deflagration during delay round firing in coal
Authors: Kennedy M. , Kerr I. D.
Published: December 2004

X‐ray studies have been made of the detonation of cartridges of various explosives that had been compressed and reduced in diameter and then fired with a delay detonator. In several cases the detonation wave that travelled along the cartridge in a direction opposite to that in which the detonator was pointing, i.e. the retrograde detonation wave, appeared to die out completely. This was not observed in similar studies with cartridges of normal densities and diameters. It is suggested that the possibility of fading of the retrograde detonation wave is connected with the way the explosive compacts under pressure, this compaction being influenced by the nature of the crystalline components of the explosive.

The study suggests one mechanism by which undetonated explosive might be left following delay round shotfiring in coal; earlier shots, causing desensitisation and consequent failure of the retrograde detonation wave. If failure of the retrograde detonation wave occurred, appreciable quantities of undetonated explosive could remain which on becoming mixed with neighbouring coal dust might be capable of deflagrating, even at atmospheric pressure.
Testing the Sensitivity of Watergel Explosives to weak shocks
Authors: Persson A. , Jerberyd L. , Almgren L.‐Å.
Published: December 2004

An equipment used for testing the response of watergel explosives to weak shocks is described. The main purpose of these tests was to investigate the shock‐initiating hazards when pumping watergel explosives of the non‐cap‐sensitive type. The explosive sample (weight ∼ 20 g) was confined in a steel cup and rapidly compressed by a steel piston. Tests were carried out with watergel explosives of both the cap‐sensitive and non‐cap‐sensitive types. In Bulkreomex (a pumpable watergel), a weak reaction was observed at a peak pressure of 1.7 kbar. As piston velocity increased, the reaction became more violent, and at a velocity above 20 m/s the reaction produced a sharp pop and smoke.
Underwater Testing of Slurry Explosives
Authors: Wollert‐Johansen P.
Published: December 2004

The facilities in use at Dyno Industrier A.S for testing explosives underwater are described. Shock wave energy and bubble energy together with detonation velocity are measured with different degrees of confinement. The use of the underwater shooting station for developing new explosives and testing of different ignition systems is explained. Finally, some comments are made on the advantages and disadvantages of having a deep salt water testing station in a Norwegian fjord.
Estimation of Toxic Fume Characteristics of Explosives from steel tube blasting
Authors: Persson G. , Persson P.‐A.
Published: December 2004

The generation of CO, NO and NO2 in blasting with ANFO has been measured. Blasting experiments in a 200 m3 rock chamber have been made with the charges confined in rock and in steel tubes. Comparison of the results shows that steel tube experiments can be used to approximately predict toxic gas generation in small diameter drill hole underground blasting. The paper describes the simple calibration and measurement techniques used. The effect of oil content in the ANFO and the effect of moisture on the walls of the chamber have been investigated.
MÉthodes d'essais pour évaluer La toxicité des fumées de tir
Authors: Carbonel P. , Bigourd J.
Published: December 2004

Le CERCHAR dispose de plusieurs méthodes pour évaluer la production de gaz toxiques dans les tirs d'explosifs: bombe de 115 1 où l'on tire 50 g ou 100 g d'explosif habituellement en présence de 150 kg de sable et sous atmosphère d'azote, chambre de 15 m3 où l'on tire 0,5 kg à 1 kg d'explosif en présence d'air, sous confinement variable (charge suspendue ou disposée dans un mortier d'acier avec ou sans bourrage et éventuellement avec un gainage). Les résultats d'essais montrent que la production de gaz toxiques varie beaucoup avec les conditions de tir: régime de détonation de l'explosif, travail accompli par les fumées de tir, réactions éventuelles des fumées avec l'oxygène atmosphérique ou avec les matériaux au contact de l'explosif (encartouchage, bourrage, gainage). Il semble que le tir en mortier d'acier avec bourrage dans la chambre de 15 m3 donne les résultats les plus proches d ce qu'on observe lors de tirs en mine. Cette méthode paraît donc préférable.
To the Problem of Standardization of the Safety Test for Permissible Explosives
Authors: Vetlický B.
Published: December 2004

The paper presents a proposal concerning a standard‐comparative test for permissible explosives used in various countries. Testing the explosives in a suspended charge or in various arrangements of the angle mortar with the reflective wall in an explosive methane/air mixture would create possibility of evaluating the behavior of permissible explosives under these model conditions and thus bringing valuable information not only for the present needs but also for the future development.
Modeling and Numerical Simulation of Combustion Process inside a solid‐propellant crack
Authors: Lu Yeu‐Cherng , Kuo Kenneth K.
Published: December 2004

Transient combustion processes inside a solid‐propellant crack cavity have been formulated and solved numerically, with emphasis placed on the coupling between combustion dynamics and propellant grain deformation and fracture. Sample calculations were performed for a center‐perforated propellant grain with an existing crack. Parametric study investigating the effect of several physical properties on the initiation of fracture was also carried out. Numerical results indicated that the existence of cracks in a propellant grain may impose a safety issue for a rocket motor due to the creation of large free volume and extra burning surface area. Comparison of calculated results of this analysis and those which do not consider propellant deformation and fracture revealed that the coupling between combustion and structural analyses is mandatory for accurate simulation of crack combustion event. It was also found that, from the parametric study, fracture initiation is very sensitive to the magnitude of pressure exponent of the propellant burning rate.
Detonability limits of methane‐oxygen mixtures at elevated initial pressures
Authors: Bauer Pascal A. , Giraud Marc , Legendre Jean‐François , Catoire Laurent
Published: December 2004

Studies and researches are conducted at ISL on the aero‐thermochemical launcher based on the RAM effect and entitled RAMAC. This type of launcher involves reactive gas mixtures which are chosen, in the thermally choked subsonic combustion mode, for their nondetonative properties. This paper gives the description of a new experimental facility at ISL, which involves a 90‐mm caliber detonation tube to carry out studies on reactive mixtures at initial pressures up to 5 MPa. First results for methane‐oxygen mixtures at 2.5 MPa and ambient temperature are given. Accordingly the upper detonability limits for these mixtures have been experimentally determined in 90 mm caliber. The experimental detonation velocities are compared with calculations by the Quartet thermochemical code.
Comparative Characteristic of Energy Content Calculating Methods for the furazan series as an example of energetic materials
Authors: Pivina Tatyana S. , Sukhachev Dmitrii V. , Evtushenko Aleksei V. , Khmelnitskii Lenor I.
Published: December 2004

The significant expenditures for organic synthesis of high‐energy materials necessitate an a priori evaluation of prospects for physical‐chemical parameters. The most important of these parameters is the heat of formation characterizing this or the other compound suggested for synthesis.

This study describes and analyzes the most well‐known and widely used schemes and methods for evaluating and predicting the energy capacity of high‐energetic materials. The accuracy of calculations is evaluated for different schemes; the limits of their applicability are determined.
Physiological Activity of Dynamites Doped with Musk Xylene. (short communication)
Authors: Chruścielska K. , Skupiński W.
Published: December 2004

Composition of catechol amines in a brain and a heart tissue of the adult male Wistar rate contacted with the DS‐1G3H dynamite doped with musk xylene has been studied. An increase of the norepinephrine concentration in the heart tissue was established.
Friction and impact sensitivity of formulations containing glycidyl azide polymer
Authors: Lusby C. A. , Ferguson D. C. , Husband D. M.
Published: December 2004

This paper describes work done to study the potential hazards of glycidyl azide polymer (GAP) based formulations. Friction and drop weight tests were performed on various GAP propellants, GAP mixed with different ingredients, and at different steps during processing of a propellant mix. The results showed that, under certain conditions, GAP formulations can be highly friction and impact sensitive.
Méthode des Biorbitales: Application Préliminaire au Calcul de l'Energie de l'Etat Fondamental de l'Atome de Beryllium
Authors: Bessis G. , Murez C. , Bratož S.
Published: December 2004

L'énergie électronique de l'état fondamental de l'atome Be a été calculée en utilisant la méthode des biorbitales (SCF–BI) dans laquelle la fonction d'onde est représentée par un produit antisymétrisé de fonctions de paire identiques. Les fonctions de base sur lesquelles les biorbitales sont développées sont les orbitales s et p données par Watson. Les fonctions de paire introduites correspondent à des états singulets. L'énergie a été minimisée directement par un procédé de descente selon la pente maximale. On trouve 0,0414 u.a. pour l'énergie de corrélation soit 44% de l'énergie de corrélation théorique. On compare la méthode (SCF–BI) à la méthode (IC) d'interaction de configuration. On établit des relations entre les coefficients dans les deux méthodes. On donne les nombres d'occupation des orbitales.
A density functional representation of quantum chemistry. I. Motivation and general formalism
Authors: Primas H.
Published: December 2004

The molecular N‐electron problem is formulated in terms of the particle density 𝔔(r) = ∑σ(r − qn) and its canonically conjugated field. Weyl's representation of the canonical commutation relations is used and a characteristic functional of the molecular system is introduced as the expectation value of Weyl's functional exp {i(α, Q) + i(β, P)}. The Hamiltonian equation of motion for the characteristic functional is derived and its cumulant approximation is discussed. The first paper is restricted to a general discussion, independent of a special choice of the Hamiltonian.

The density functional representation may be considered as a step towards a formulation of a renormalized quantum chemistry. The lowest order cumulants of the characteristic functional are accessible to actual precision measurements; on the other hand, most experiments are correctly represented by a characteristic functional of the Gaussian type. The significance of the higher order correlations is neither theoretically nor experimentally disclosed yet, their possible importance for biological systems is mentioned, and the question is raised of how far quantum mechanics is empirically confirmed for extremely complex systems.
The theory of local degeneracy
Authors: Joseph A.
Published: December 2004

The concept of a locally degenerate Hamiltonian is defined. It is shown that such a Hamiltonian is, with respect to a particular quantum number, degenerate in a single level only. Some examples of single‐particle systems suggested by a study of the stereographic projection are examined, a comparison being made with the Kepler problem. It is found, in these examples, that the degenerate level lies at the limiting value of the potential energy at large distances and the condition for the existence and the properties of these states are deduced. It is also shown that for such states certain operators may have eigenfunctions in common with the Hamiltonian and for this reason they are called local constants of the motion. Like ordinary constants of the motion, they help to simplify the eigenvalue problem and, in particular, the singular inverse square law potential is studied by this approach. Finally, the application of the results to resonance scattering (by bound states near the continuum) and to the calculation of the number of bound states is indicated.
Wellenmechanische Absolutrechnungen an Molekülen und Atomsystemen mit der SCFMOLC(LCGO) Methode. VIII. Das System (Li2H)+
Authors: Diercksen G. , Preuss H.
Published: December 2004

Das (Li2H)+ wurde unter Berücksichtigung aller 6 Elektronen mit dem Allgemeinen Programmsystem/SCFMOLC(LCGO) Verfahren im linearen Fall für 5 verschiedene Abstände RLiH berechnet, wobei das H‐Atom in der Mitte lag. Es ergab sich im Minimum eine Gesamtenergie von −15,289 a.E. der Bindungsabstand RLiH berechnet sich zu 3,14 a.E. Die Ionisierungsenergie beträgt dabei 15,1 eV. Die Bildungsenergie aus LiH und Li+ ergibt sich beim Vergleich der SCF‐Rechnungen an den beteiligten Systemen zu 59,7 kcal/mol (2,58 eV). Aus der Potentialkurve in der Nähe des Minimums berechnet sich die Kraftkonstante der symmetrischen Schwingung zu k = 0,13777 × 106 dyn/cm, aus der eine Frequenz ω = 577,9 cm−1 resultiert.
Application of the AMO method to non‐alternant systems
Authors: Silberman Z. , Gershgorn Z. , Pauncz R.
Published: December 2004

The alternant molecular orbital method (AMO) is more efficient if the molecular orbitals are chosen in an optimal way. A method is given of how to determine the most effective pairing scheme and how to choose the starting molecular orbitals. Applications to non‐alternant systems (fulvene and azulene) show that one can achieve substantial improvement in the energy by determining the best MO's.
A field theoretical description of states with different orbitals for different spins
Authors: Berggren K.‐F. , Johansson B.
Published: December 2004

A field theoretical formulation is given for the method of different orbitals for different spins (DODS). For an infinite system DODS describes an antiferromagnetic state and to account for this spin ordering a Gorkov‐type of factorization is introduced. A corresponding gap equation is derived, where a non‐zero solution indicates the presence of long‐range order in the system. Actually the formulation given is general enough as to render DODS as a special case. As shown, we may also obtain a ferrimagnetic as well as a density wave state solution depending on the special characteristics of the system at hand.

A related type of antiferromagnetism is described by the Overhauser spin density wave (SDW) state and also this theory is formulated in a field theoretical language. The similarities and differences between DODS and SDW are discussed. The energy expressions for the two states are given within the Hartree‐Fock approximation.

It is proposed that the SDW state could be used to partly account for the correlation problem in molecules, as well as the method of DODS which has previously been employed for that purpose.
Open‐ and closed‐shell states in few‐particle quantum mechanics. I. Definitions
Authors: Kutzelnigg Werner , Smith Vedene H.
Published: December 2004

The distinction between open‐ and closed‐shell states is quite important in few‐particle quantum mechanics‐especially in view of the correlation problem. The current definitions of such states and of shells in general are, however, only meaningful if one can assume that the independent particle model is a valid description of the state under consideration. Definitions are given in terms of rigorous quantum‐mechanical concepts which allow a classification of states irrespective of any model assumptions. Closed‐shell states and different types of open‐shell states are distinguished. Sufficient criteria for a state to be a closed‐shell state are derived in terms of unitary invariants of the one‐particle density matrix of this state.