bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hochauflösungs‐Protonenresonanz‐Spektren von Nitroäthylen, 1‐Nitropropen‐(1) und 1‐Nitropropen‐(2)
Authors: Fröhlin H. J. , Loos K. R. , Günthard Hs. H. 
Published: December 2004

AbstractThe proton resonance spectra of nitroethylene, 1‐nitropropene‐(1), and 1‐nitropropene‐(2) have been measured in solution with high resolving power at 60 and 100 MHz. A full set of chemical shift and coupling constants, obtained from analysis of the spectra in terms of ABC, ABX3 and ABCD2 systems, respectively, is given.
Zur Kenntnis des Kohlenstoffringes. 81. Mitteilung [1]. Acetolyse des 3,3,8,8‐Tetramethyl‐cyclodecyl‐p‐toluolsulfonates
Authors: Prelog V. , Troxler E. , Westen H. H. 
Published: December 2004

AbstractAcetolysis of 3,3,8,8‐tetramethyl‐cyclodecyl p‐toluenesulfonate yields 3,3,8,8‐tetramethyl‐trans‐cyclodecene‐(1) (6), 4,4,9,9‐tetramethyl‐cis‐cyclodecene‐(1) (4), and 4,4,9,9‐tetramethyl‐trans‐cyclodecene‐(1) (5). In each case 12 to 13 per cent of the product involves transannular hydride shifts. The rate constant k25 = 4,35 · 10−5 s−1 is approximately the same as for cyclodecyl p‐toluenesulfonate. The reaction is discussed in terms of conformational analysis.
Synthese des (±)‐VerrucarinsäUrelactons. Verrucarine und Roridine, 16. Mitteilung [1]
Authors: Achini R. , Meyer U. , Tamm Ch. 
Published: December 2004

AbstractThe synthesis of (±)‐verrucarinolactone (threo‐α‐hydroxy‐β‐methyl‐Δ‐valerolactone) is described.
Elektronen‐Donator‐Acceptor‐Komplexe bei Polypeptiden III. Optische Aktivität von intra‐und intermolekularen Charge Transfer‐Absorptionbanden
Authors: Moser P. 
Published: December 2004

AbstractOptical activity, i. e. circular dichroism (CD) and optical rotatory dispersion (ORD) associated with charge‐transfer (CT) absorption bands were found for intra‐ and intermolecular electron‐donor‐acceptor (EDA)‐complexes containing centers of configurational asymmetry.
Zur Deutung der thermodynamischen Daten von Komplexbildungsreaktionen I
Authors: Anderegg G. 
Published: December 2004

AbstractThe free enthalpy of complex formation, corrected for the involved change of the number of particles, is described as a sum: δGta + δGtu (= δG ‐ δGm), which permits the separation of the temperature dependent terms. Following Gurney, it is supposed that the temperature dependent free enthalpy δGta varies in the same way as the reciprocal of the dielectric constant of the solvent. This model furnishes some relations which permit a correct description of the complex formation in terms of an electrovalent and of a nonelectrovalent interaction.
Spektroskopische Untersuchung einiger α,β‐ungesättigter cyclischer Ketone
Authors: Marsh Grace , Kearns D. R. , Schaffner K. 
Published: December 2004

AbstractThe results of the spectroscopic investigation of the steroidal enones 1–6 can be summarized as follows:

Direct absorption and phosphorescence excitation techniques have been used to locate the 3(n,π*) states, and in each case it has been found to be the second triplet state.
The lowest excited state in each case is assigned as 3(π,π*) state.
The diffuseness in the phosphorescence emission from the 3(π,π*) states is attributed to a large change in the molecular geometry upon excitation (probably to a non‐planar configuration).
The diffuseness in the S→ Tn,π* absorption is correspondingly attributed to interaction between the 3(n,π*) and 3(π,π*) states. A summary of the energy levels for these compounds is given in Fig. 4.
Synthese von substituierten 1, 2‐Malonyl‐1,2‐dihydrocinnolinen (1,3‐Dioxo‐2, 3‐dihydro‐1H‐pyrazolo [1, 2‐a] cinnolinen) mit antiinflammatorischen Eigenschaften
Authors: Schatz F. , Wagner‐Jauregg Th. 
Published: December 2004

AbstractA new class of antiphlogistic substances is described. They are 4‐phenyl‐1, 2‐dihydrocinnolins diacylated in 1, 2‐position by alkylmalonic acids. The compound which pharmacologically has been investigated most thoroughly is cinnopentazone (II). Its synthesis and behaviour towards hydrolytic and oxidative agents are described. Some relations between the chemical structure of these series of substances and their antiinflammatory activity as well as their classification as antiphlogistics according to some model reactions are discussed.
Synthese von A‐Homo‐19‐norsteroiden. Über Steroide, 214. Mitteilung
Authors: Wieland P. , Anner G. 
Published: December 2004

Abstract3‐Oxo‐19‐mesyloxy‐Δ1; 4‐steroids and their 19‐chloro analogues are converted into 4‐oxo‐Δ1; 5(10)‐A‐homo‐19‐norsteroids by treatment with lithium and biphenyl in tetrahydrofuran solution.
Synthèses dans la série des bis‐indéno‐fluorènes IV [1] Hydroxy‐8‐dihydro‐9, 15‐7H‐bis‐indéno[2, 1‐b;2′, 1′‐g]fluorène
Authors: Chardonnens Louis , Hammer Wolfgang 
Published: December 2004

Abstract8‐Hydroxy‐9, 15‐dihydro‐7H‐diindeno [2, 1‐b;2′, 1′‐g] fluorene, a derivative of a new mono‐angular diindenofluorene system, has been synthesised in 6 steps (overall yield 42%) starting from 9‐oxo‐fluorene‐1‐carbaldehyde and acetophenone. The corresponding hydrocarbon could not be obtained by reductive scission of the hydroxyl group.
Eine neue, einfache Methode zur Synthese von Cystinpeptiden
Authors: Kamber B. , Rittel W. 
Published: December 2004

AbstractA report is given on the conversion of S‐trityl‐cysteine‐containing protected peptides to cystine peptides by a reaction with iodine in methanol. The new method permits the synthesis of symmetrical, open‐chain unsymmetrical, and especially cyclic cystine peptides.
Herstellung und Umsetzungen von β‐Lactamen
Authors: Haug Th. , Lohse F. , Metzger K. , Batzer H. 
Published: December 2004

AbstractThe cycloaddition of N‐chlorosulfonyl‐isocyanate with isoprene, butadiene and a polyolefin as well as the reaction of ketenes with some bis‐azomethines were investigated. Suitably substituted bis‐azomethines could be separated in the rac. and the meso‐form. The reactivity of the azetidinones towards hydrolysis and hydrogenation was tested. Attempts to polymerise 4‐vinyl‐azetidin‐2‐one, polyazetidinone and N‐substituted bis‐azetidinones to give cross‐linked poly‐β‐amides were not successful.
Gas‐Chromatographie und Massenspektrometrie der Trimethylsilyl‐enoläther von 5α‐ und 5β‐Cholestan‐3‐on
Authors: Vetter W. , Walther W. , Vecchi M. , Cereghetti M. 
Published: December 2004

AbstractTrimethylsilyl‐enolethers of 5α‐ and 5β‐cholestan‐3‐on were investigated by gas chromatography and mass spectrometry. These derivatives are readily prepared and well suited for gas chromatographic analysis. In the mass spectrum they show fairly intense fragmentation, which appears to be characteristic for some structural elements in the surroundings of the functional group (excluding stereochemistry). This fragmentation may be useful for the structure elucidation of 3‐oxo‐steroids and related compounds.For comparison purposes the corresponding enolacetates were also investigated.
Über die Konstitution zweier neuartiger «dimerer» Indolalkaloide Pycnanthin und Pleiomutinin 132. Mitteilung über Alkaloide
Authors: Gorman A. A. , Dastoor N. J. , Hesse M. , von Philipsborn W. , Renner U. , Schmid H. 
Published: December 2004

AbstractThe «dimeric» indole alkaloid (+)‐pycnanthine (2) has been isolated, along with (+)‐pleiocarpamine, (+)‐quebrachamine, (+)‐macusine B and an unknown alkaloid D from Pleiocarpa pycnantha (K. SCHUM.) STAPF, var. pycnantha M. PICHON. An investigation of its chemical and spectroscopic properties has led to the determination of structure 2 for this base. Its 6′,7′‐dihydro derivative has been shown to be identical with the alkaloid pleiomutinine, previously isolated from Pleiocarpa mutica BENTH.
Niederdruck‐Oligomerisation von Mono‐Olefinen mit löslichen Nickel/Aluminium‐Bimetallkatalysatoren, Teil I Entwicklung neuer Katalysatorsysteme auf der Basis von π‐Cyclobutadien‐Nickel(II)‐Verbindungen
Authors: Onsager Olav‐Torgeir , Wang Hagbarth , Blindheim Ulf 
Published: December 2004

AbstractMixtures of π‐tetramethylcyclobutadiene‐nickeldihalides and LEWIS acids such as alkylaluminiumhalides in organic solvents represent new highly active homogeneous catalysts for the dimerization of ethylen, propene and butene under mild conditions. As a cocatalyst LEWIS bases may be used, in particular those containing trivalent phosphorous.
Recherches sur la formation et la transformation des esters LXXXII [1]. Sur la différenciation entre structures δ2‐amino‐2 ou imino‐2 dans des composés S, N‐hétérocycliques pentagonaux et hexagonaux à cycle par ailleurs saturé
Authors: Rabinowitz Joseph 
Published: December 2004

AbstractComparison of the NMR. spectra in CDCl3 of the heterocyclic bases obtained from the cyclisation of ω‐(N‐thiocarbamoylamino) ethyl (or propyl)‐alcohols (or their orthophosphoric or sulfuric monoesters) to those of model compounds II (n = 1 or 2) and III (n = 1 or 2) has shown that: (1) In the case of five membred rings the CN double bond is always endocyclic (Ib, n = 1) should R be aromatic, araliphatic or aliphatic; (2) In the case of six membered rings the CS double bond is cnclocyclic when R is aliphatic or araliphatic (Ib, n = 2), and exocyclic when R is aromatic (I a, n = 2), with the exception of 2‐(o‐carboxyphcnylamino)‐dihydro‐δ2‐m (Ib, n = 2, K = o‐carboxyphcnyle).In CF, COOH, all five membered rings (I b, n = 1) show a triplet for the C‐4 methylenic protons, whereas all the six membered rings (Ia or I b, n = 2) with the exception of I b, n = 2, R = o‐carboxyphenyle, are represented b y a double triplet for the C‐4 protons (samt. protonated spccics). Only one triplet is observed when the 3 position is substituted.Thiocarbamoylation of hydrazinoethanol or its orthophosphoric or sulfuric monoesters canoccur at either of the two nitrogen atoms, thus yielding upon cyclization five‐ (IT′) or six‐membered rings (Va or Vb). The NMR spectra of compounds I V in (CIl,), SO show a singlet for 2 amino pro‐tons (3‐amino) and there is no further structural problem. The NMR spectra of compounds T′ in (CT), SO show a triplet for one amino proton coupling with the neighboring methylenic protons. I n this case, mode1 compounds are needed to assign the position of the CN double bond ( e x cyclic V a or cndocyclic V b). When R = o‐carboxyphenylc, the CN double bond is probably endoc, yclic (Vb) because this ccimpound and 2‐(o‐carboxyphenvlarnino)‐dihydro‐δ2 have very similar UV spectra.
Gymnemagenin, Struktur und O‐Isopropylidenderivate Glykoside und Aglykone. 313. Mitteilung
Authors: Stöcklin W. 
Published: December 2004

AbstractSeveral O‐isopropylidene derivatives of gymnemagenin (5), a hexahydroxytriterpene from the leaves of Gymnema sylvestre R. Br. have been prepared, which may perhaps be useful to correlate gymnemagenin with other triterpenes. From the data obtained we conclude that gymnemagenin is 3β, 16β, 21β, 22α, 23, 28‐hexahydroxy‐olean‐12‐ene.
Über die Natur von Schwermetallkomplexen aus 2‐(2‐Hydroxyphenyl)‐4‐carboxy‐2‐H‐napht[1.2‐d]triazolen
Authors: Steiner E. , Schetty G. 
Published: December 2004

Abstract2‐(2‐hydroxyphenyl)‐4‐carboxy‐naphtho [1.2‐d] triazoles are terdentate ligands which can form 1:1 complexes with CuII and NiII ions, and 1:1 as well as 1:2 complexes with CrIII‐ions. All these complexes are characterized by ortho‐condensed 6/6‐membered rings, the 1:2 chromium complexes having the DREW‐PFITZNER arrangement. This behaviour, which differs from that of comparable o‐hydroxy‐o′‐carboxy‐diaryl azo‐dyestuffs, is due to the different dimensions of the compared ligands.
Die Reaktion von 1,2‐Epoxy‐octan mit 2‐Dimethylamino‐äthanol
Authors: Tobler Erich 
Published: December 2004

Abstract2‐Dimethylaminoethanol reacts with 1,2‐epoxyoctane presumably via a hydrogen‐bonded complex to form a quaternary ammonium compound which exhibits a fair stability at lower temperatures. At higher temperatures the quaternary structure decomposes with the resulting formation of a wide variety of products. Most of the products have been identified and a reasonable mechanistic picture for their formation is presented. The main products of the reaction are 1‐(ß‐dimethylaminoethoxy)‐2‐octanol (IIIa) and 1‐dimethylamino‐2‐octanol (IV), the latter being formed according to several pathways concurrently with ethylene oxide, 2‐methyl‐4‐hexyl‐1, 3‐dioxolane (VI), and 2‐hexyl‐1, 4‐dioxane (VII). Some of the higher molecular weight products are secondary products resulting from the action of epoxide on the primary reaction products IIIa and IV. The relative amount of each product formed depends on the ratio of starting materials and reaction temperature. In the presence of an additional hydroxylic solvent such as ethanol, the solvent enters also into the reaction.
Die Bildungsenthalpie 1,6‐überbrückter [10] Annulene
Authors: Bremser W. , Hagen R. , Heilbronner E. , Vogel E. 
Published: December 2004

AbstractThe enthalpies of formation of 1.6‐methano‐[10] annulene (IV) (ΔHf298 (IV, g) = 75.2 ± 0.6 kcal mol−1), 1.6‐imino‐[10] annulene (V) (ΔHf298(V, g) = 87.8 ± 0.7 kcal mol−1) and of 1.6‐oxido‐[10] annulene (VI) (ΔHf298(VI, g) = 47.8 ± 1.2 kcal mol−1) have been determined by combustion calorimetry. The difficulties connected with an attempt to derive meaningfull «resonance energies» are discussed.
Die reduktive Spaltung von Azofarbstoffen durch Dihydrochinoxaline
Authors: Schellenberg M. , Steinmetz R. 
Published: December 2004

AbstractThe kinetics of the reduction of substituted azobenzenes by dihydroquinoxalines have been measured. Azo‐compounds with electron‐donating substituents in o‐ or p‐position are reduced to the amines in neutral or acid solution, whereby two molecules of the reducing agent are consumed. If such substituents are absent, the reaction stops at the hydrazo stage. This is also the case with cleaveable azo‐compounds in strongly alcaline solution.Our kinetic measurements of the reductive cleavage reaction of methylorange are in agreement with only one mechanism, which is discussed in detail. The very high reactivity of protonated methylorange may be attributed to the formation of a mesomeric quinoid structure. Knowing the pH‐dependence of the reaction rate allows the determination of the pK‐value of the extremely unstable hydrazo stage of methylorange. The structure of the dihydroquinoxaline has a strong influence on ΔH‡ and ΔS‡, and therefore on the reaction rate.
Die NO‐katalysierte Isomerisierung von 3‐Methylen‐1,5,5‐trimethyl‐cyclohexen zu 1,3,5,5‐Tetramethyl‐1,3‐cyclohexadien in der Gas‐Phase. Thermodynamische Daten aus Gleichgewichtsmessungen
Authors: Egger Kurt W. , Jola M. 
Published: December 2004

AbstractThe composition of equilibrated gaseous mixtures of 3‐methylene‐1,5,5‐trimethylcyclohexene (MTC) and 1,3,5,5‐tetramethyl‐1,3‐cyclohexadiene (TECD) have been measured for temperatures ranging between 302 and 410°C. Nitrogen oxide was used as catalyst. Equilibrium was approached from either side. The least squares regression analysis of the observed temperature dependence of the equilibrium constants K1.2 = k1/k2 = (TECD)eq./(MTC)eq. yields (with standard errors)

This results in ΔH1.2(300°K) = 0.4 ± 0.3 kcal/mole and ΔS1.2(300°K) = 1.4 ± 0.8 cal/°‐mole. The fact that the reaction is practically thermoneutral implies that the secondary, «biallylic» CH bond in MTC is equally strong as the primary «biallylic» CH bond of the 1‐methyl group in TECD.The observed enthalpy and entropy differences between the two isomers are in agreement with prediction based on the concept of additivity of thermodynamic increment properties (ref. [5]). The results of this work also yield a value of 23.7 cal/°‐mole for the entropy contribution characteristic of the 1,3‐cyclohexadiene ring structure. When combined with the ARRHENIUS parameters, reported earlier [1] for k1, the results of this work yield for the back reaction log k2 (1/mole‐s) = 8.25–30.2/4.58 × 10−3 T(°K).
Reaktion von Kaolinit mit Kaliumhydroxid
Authors: Sticher H. , Bach R. 
Published: December 2004

AbstractThe reaction of kaolinite with potassium hydroxide (1 to 9N) was investigated between 70 and 90°C. During a first period of the reaction the content of Si and Al in solution increased and reached a maximum in 100 to 240 minutes, depending on KOH concentration and temperature; then an amorphous aluminosilicate gel formed. After an induction period, again depending on KOH concentration and temperature, the concentrations of Si and Al decreased rapidly, due to the formation of a crystalline potassium aluminosilicate.
Photochemistry of 2‐Cyclohexene‐imines and 2,3,4,4a,5,6‐Hexahydroquinolines. Preliminary communication
Authors: Margaretha Paul 
Published: December 2004

AbstractThe 2‐cyclohexene‐imines 2b–2d and the hexahydroquinolines 5a, b are synthesized. n,π*‐Excitation of these α,β‐unsaturated imines leads to (E/Z) isomerization for compounds 2 while compounds 5 are unreactive. No cyclobutanes are formed from 2 or 5 under these conditions in the presence of olefins, and only 2d adds to 2,3‐dimethyl‐2‐butene via the CN bond to give an azetidine. On π,π* excitation 2 and 5 rearrange to the corresponding β,γ‐unsaturated imines 8 and 9 with low efficiency. It is concluded that the failure of such imines to undergo [2+2]‐photocycloadditions with olefins is not mainly due to radiationless decay via (E/Z) isomerization.
Properties and microstructures of epoxy resin/TiO2 and SiO2 hybrids
Authors: Yano Shoichiro , Ito Tatsuro , Shinoda Kenichi , Ikake Hiroki , Hagiwara Toshiki , Sawaguchi Takashi , Kurita Kimio , Seno Manabu 
Published: December 2004

AbstractEpoxy resin/TiO2 and epoxy resin/SiO2 hybrids were prepared by different procedures, and their mechanical properties were correlated to their microstructures, as indicated by small‐angle X‐ray scattering (SAXS) measurements. Epoxy resin/TiO2 hybrids were prepared by mixing the epoxy resin (EP828) with N‐(2‐aminoethyl)‐3‐aminopropyltrimethoxysilane (S320) in acetone, and then titanium‐n‐butoxide (TnBU) was added. In addition, epoxy/SiO2 hybrids were prepared by mixing EP828 with a curing agent, a diamino heterocyclic compound (B002) in acetone, and an organo silica sol (silica nanoparticles dispersed in methylethylketone) was added. In the EP828/S320/TiO2 hybrid systems, the TiO2 component was attached to both of the chain ends of the epoxy matrix, hence leading to the formation of inorganic domains via the covalent bonds. SAXS profiles of these hybrids showed peaks at q = 2.3 nm−1, caused by interference between the domains. The storage modulus increased with increasing TiO2 content above the Tg, owing to the strong interactions between TiO2 and the epoxy matrix. The tanδ peak position did not change, although the intensity decreased with increasing TiO2 content. The SAXS profiles of the EP828/B002/SiO2 hybrids were very different to those of the corresponding EP828/S320/TiO2 hybrids, and indicated that SiO2 particles with rough surfaces were randomly dispersed in the epoxy matrix. The storage moduli of the EP828/B002/SiO2 hybrid systems increased only slightly with SiO2 content, because of the weak interactions. These mechanical properties are well explained by the microstructures derived from the SAXS profiles. Copyright © 2004 Society of Chemical Industry
A Tomonaga gas model for aromatic hydrocarbons
Authors: Basu Sadhan 
Published: December 2004

AbstractConsidering the π electrons in aromatic hydrocarbons as forming a two‐dimensional free‐electron gas, the Tomonaga method has been followed to determine the frequency of collective oscillations when an electron is excited in these systems. The calculated and experimental frequency have been found to be in excellent agreement, although the collective coordinate was not conjugate to the collective momentum in these systems containing only few free π electrons.
Generalized brillouin theorem for multiconfigurational SCF theories
Authors: Levy Bernard , Berthier Gaston 
Published: December 2004

AbstractThe matrix elements of the total Hamiltonian between a multiconfigurational SCF wave function and some well‐defined linear combinations of excited Slater determinants are equal to zero. By means of this generalized Brillouin theorem it is possible to estimate the improvements to be expected from a subsequent configuration‐interaction treatment. The expression of the effective potential for the orbitals can be also derived in the frame of a given multiconfigurational theory. As an example, the case of the CMC‐SCF method recently suggested [9] is examined.
A systems and control theoretic approach to dynamic neurotransmitter balance: Normal, abnormal, and “catastrophic”
Authors: Kaufman Joyce J. , Koski Walter S. , Peat David 
Published: December 2004

AbstractWe formulated a pharmacological–physiological systems analysis and control theory based on interactive neuronal feedback loops (the effects of endogenous neurochemical diseases and exogenous psychotropic and other CNS drugs on neurotransmitter synthesis and release, reuptake, and metabolism) for normal, abnormal, and catastrophic situations.We were concerned primarily with the problems of stability or instability which might lead the system to exhibit catastrophic behavior. We set up the systems diagrams for the neurotransmitter systems and in that single framework were able to describe endogenous neurochemical disorders, the effect their drug treatment modalities had on the dynamic neurochemical balance, the effect psychotropic or other CNS drugs such as narcotics and narcotic antagonists had on neurotransmitter balance, and the interactive effect that multiple drug administration would have on neurotransmitter balance. Endogenous neurochemical disorders such as schizophrenia, Parkinsonism, depression, and mania should show up mathematically either as overly damped solutions if there is too little normal neurotransmitter or as catastrophically divergent instabilities if there is too much normal neurotransmitter. Improper mixed drug therapies, as well as the devastating effect of eating foods such as cheese (which contains sympathomimetic amines which potentiate the release of catecholamines from the presynaptic nerve endings) while on MAOI therapy also show up as mathematical, usually catastrophic, instabilities. We also indicated how this systems analysis and control theory could be put on small interactive computer terminals for use in clinical management and proper drug therapy of patients with neurochemical disorders.
Second quantization for systems with a constant number of particles in the Dirac notation
Authors: Koutecký Jaroslav , Laforgue Alexandre 
Published: December 2004

AbstractThe relation between the completeness condition for an appropriate one‐particle basis set and the occupation number representation (second quantization) is shown for the time‐independent case. The explicit expressions for the basic symmetric operators are derived in the Dirac bra–ket notation. The physical meaning of these operators, the algebra as well as the connections with the one‐electron density matrix and with the projector on the Fermi sea in the one‐electron approximation, follow directly from these expressions. The generalization for a nonorthogonal basis and the algebra for corresponding basic operators are formulated. The connection with the notion of the molecular diagrams of different kinds for the nonorthogonal atomic orbitals is shown. The Mulliken populations and the Chirgwin–Coulson bond orders are equal to the diagonal and offdiagonal elements of the molecular diagram 1, respectively. The matrix elements of the projector on the Fermi sea in the one‐electron approximation in the representation of nonorthogonal atomic orbitals are elements of the molecular diagram 2.