bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acidities of Hydrochloric Acid in Water/Acetic Acid and in Water/Acetic Acid/Formaldehyde Mixtures: Investigations with the indicator method and with the nmr method. 31st communication on investigations in textile chemistry
Authors: Gorrie Thomas M. , Zollinger Heinrich 
Published: December 2004

AbstractThe NMR. chemical shift (δH) of the acidic proton in the systems HCl/H2O and HCl/H2O/HOAc was correlated with the acidity function (Ho)I determined by the indicator method. By using three indicators it could be shown that, except for solutions with very low concentrations of hydrochloric acid, the acidity function (Ho)I correlates with δH in a way which can be rationalized. Addition of 7,5% (W) formaldehyde to these systems changes (Ho)I and δH very significantly, particularly in systems with low water content. Logarithmic rate constants of cellulose formal formation in HCl/H2O/HOAc systems which do not show a linear relationship with (Ho)I, measured without presence of formaldehyde, do so if (Ho)I is measured with formaldehyde present. For these systems, however, δH is not a suitable acidity parameter.
Addition von Acetylendicarbonsäuredimethylester an Imidazole; Aminierung der Addukte: neue Synthesen von 3‐(2‐Imidazolyl)‐2‐pyridon‐4,5‐dicarbonsäureamiden und Pyrido[1,2‐a]pyrazinen
Authors: Troxler Franz , Weber Hans Peter , Jaunin André , Loosli Hans‐Rudolf 
Published: December 2004

AbstractThe reaction between dimethyl acetylene dicarboxylate and 2‐amino‐1‐methylimidazole affords dimethyl 2‐amino‐1‐methyl‐1,3‐diazepine‐5,6‐dicarboxylate in low yield. This 1:1 – adduct was formed by addition of the acetylenic compound to the enamine double bond of the imidazole ring followed by ring enlargement. On the other hand, 2:1 – adducts to the imine bond are isolated in moderate yield when dimethyl acetylene dicarboxylate is treated with either 1‐methyl‐2‐methylmercapto‐imidazole or 1‐methyl‐2‐methylmercapto‐imidazoline. These adducts behave differently on heating with ethylamine: the adduct of the imidazole series cyclizes to the pyridone 15 with concomittant loss of one carboxamide group whereas that of the imidazoline series forms a pyrido[1,2‐a]pyrazine derivative 20, both in high yield. The possible reaction mechanisms are discussed. 13C–NMR.‐spectroscopy and X‐ray analysis were used in the determination of several structures.
Ein neuer, ergiebiger Zugang zu Dihydroactinodiolid und α‐substituierten Furanderivaten
Authors: Von Wartburg Beat R. , Wolf Hans R. 
Published: December 2004

AbstractDihydroactinodiolid 1 is formed in high yields by oxidation of the alcohols 2 and 3 and the ether 4. Furthermore, the oxidation of the epoxy‐alcohols 13 and 14 gives rise to the formation of furancompounds (15 and 16, respectively).
Photochemische Primärreaktionen α‐verzweigter aliphatischer Ketone und Aldehyde in lösung
Authors: Blank Bernd , Henne Andreas , Fischer Hanns 
Published: December 2004

AbstractUV.‐Irradiation of methyl t‐butyl ketone, di‐t‐butyl ketone, pivalaldehyde and isobutyraldehyde in benzene solution leads to chemically induced dynamic nuclear polarization (CIDNP.) of the parent compounds and of various reaction products. CIDNP.‐effects and product distributions establish type I α‐cleavage predominantly of triplet state molecules as the major primary photochemical step for all the four α‐branched carbonyl compounds. In chlorinated solvents singlet reactions interfere with the triplet processes.
Electronic States of 1,5‐Cyclooctadiyne Radical Cation and of Related Systems: The electronic structure of cis‐bent carbon‐carbon triple bonds
Authors: Bieri Gerhard , Heilbronner Edgar , Kloster‐Jensen Else , Schmelzer Andreas , Wirz Jakob 
Published: December 2004

AbstractThe photoelectron spectra of 1,5‐cyclooctadiyne (2) and of 1,6‐dithiacyclodeca‐3,8‐diyne (3) have been recorded. The first four (2) or six (3) PE. bands have been assigned as follows; in increasing order of ionization potentials:

The relative sequence and the positions of the PE. bands are explained in terms of through‐bond and through‐space interactions between the basis π‐orbitals and σ‐orbitals of appropriate symmetry behaviour.An analysis of the PE. spectroscopic data for cyclooctyne (1) and for (2) indicates that a cis‐bend of the acetylene moiety by θ < 20° leads to a split in energy of the in‐plane and out‐of‐plane basis π‐orbitals which is smaller than ∽ 0.2 eV. This is in agreement with the predictions derived from semiempirical models (MINDO/2, SPINDO) and qualitative orbital arguments. However, it is shown by using orbital localization procedures, that the rationales underlying the two semiempirical models differ significantly.
Metal Complexes with Macrocyclic Ligands, V. Formation and dissociation kinetics of the pentaco‐ordinated Ni2+, Cu2+, Co2+ and Zn2+ complexes with 1,4,8,11‐tetramethyl‐1,4,8,11‐tetraazacyclotetradecane
Authors: Hertli Liselotte , Kaden Thomas A. 
Published: December 2004

AbstractThe formation and dissociation kinetics of the pentaco‐ordinated Cu2+, Ni2+, Co2+ and Zn2+ complexes with 1,4,8,11‐tetramethyl‐1,4,8,11‐tetraazacyclotetradecane (4‐MeCyclam‐14) was studied by pH‐stat techniques and spectrophotometrically. The rates of the reactions between 4‐MeCyclam‐14 and each of the four metal ions, although slower than normal complexations by a factor of 103−104, closely follow the order Cu2+ > Zn2+ > Co2+ > Ni2+, found for the rate of water exchange. This implies that beside water exchange an other constant factor plays an important role in the rate determing step. The dissociation of the pentaco‐ordinated 4‐MeCyclam‐14 complexes is acid catalyzed. The limiting rate for acid dissociation is not reached even in 2.5M HNO3 in the case of Ni(4‐MeCyclam‐14)2+. From the formation and dissociation rates stability constants have been calculated, which do not show any macrocyclic effect.
Anil‐Synthese. 11. Mitteilung. Über die Darstellung von in 4′‐Stellung substituierten 4‐Styryl‐stilben‐, 4‐(Benzo[b]furan‐2‐yl)‐stilben‐ und β‐(2‐Phenyl‐benzo[b]furan‐6‐yl)‐styrol‐Derivaten
Authors: de Buman Alain , Siegrist Adolf Emil 
Published: December 2004

AbstractSchiff'sche Basen aus Stilben‐4‐carbaldehyd, 2‐(p‐Formyl‐phenyl)‐benzo[b]furan und 2‐Phenyl‐6‐formyl‐benzo[b]furan und p‐Chloranilin können mit p‐tolyl‐ bzw. methyl‐substituierten heterocyclischen und carbocyclischen Aromaten in Gegenwart von Dimethylformamid und Kaliumhydroxid bzw. Kalium‐t‐butylat in die entsprechenden Stilben‐bzw. Styrol‐Derivate übergeführt werden («Anil‐Synthese»).Die Lage der Absorptions‐ und Fluoreszenz‐Maxima der dargestellten Grundkörper der Benzo[b]furan‐Reihe wird mit derjenigen entsprechender Stilben‐Verbindungen verglichen.
Photoinduzierte 1, 3‐dipolare Cycloaddition von 3‐Phenyl‐2H‐azirinen an Azodicarbonsäure‐diäthylester. 32. Mitteilung über Photoreaktionen
Authors: Gilgen Paul , Heimgartner Heinz , Schmid Hans 
Published: December 2004

AbstractIrradiation of 2, 2‐dimethyl‐3‐phenyl‐ (1a), 2, 3‐diphenyl‐2H‐azirine (1b) or the azirine‐precursors 1‐azido‐1‐phenyl‐propene (2a) and 1‐azido‐1‐phenyl‐ethylene (2b), respectively, in benzene in the presence of azodicarboxylic acid diethylester, yields the corresponding 1, 2‐carbethoxy‐3‐phenyl‐Δ3‐1, 2, 4‐triazolines 4a–d (Scheme 1).Refluxing 4 (a, c or d) in 0, 2–0, 4M aqueous ethanolic potassium hydroxide leads to the formation of the 1‐carbethoxy‐3‐phenyl‐Δ2‐1, 2, 4‐triazolines 6 (a, c or d). Under the same conditions 4b is converted to 3, 5‐diphenyl‐1, 2, 4‐triazole (7b, Scheme 2). In 10M aqueous potassium hydroxide solution heating of either 4 (c or d) or 6 (c or d) yields the 3‐phenyl‐1, 2, 4‐triazoles 7 (c or d).Photolysis of 1‐carbethoxy‐5, 5‐dimethyl‐3‐phenyl‐Δ2‐1, 2, 4‐triazoline (6a) in benzene in the presence of oxygen and trifluoroacetic acid methylester gives the 5‐methoxy‐2, 2‐dimethyl‐4‐phenyl‐5‐trifluoromethyl‐3‐oxazoline (13, Scheme 5). 5, 5‐Dimethyl‐3‐phenyl‐1, 2, 4‐triazole seems to be the intermediate, which on losing nitrogen gives the benzonitrile‐isopropylide (3a).
Comparison of 13C‐ and 1H‐Magnetic Resonance Spectroscopy as Techniques for the Quantitative Investigation of Dynamic Processes. The cope rearrangement in bullvalene
Authors: Oth Jean F. M. , Müllen Klaus , Gilles Jean‐Marie , Schröder Gerhard 
Published: December 2004

AbstractThe potential advantages of 13C‐(1H‐noise decoupled) spectroscopy (in the Fourier transform mode) over 1H‐spectroscopy for the quantitative investigation of molecular dynamic process is discussed. The Cope rearrangement in bullvalene, an example of complex exchange of spins over different magnetic sites, has been studied by both kinds of spectroscopy as a test.
Beweis der absoluten Konfiguration der Xanthophyll‐5, 6‐epoxide (Luteinepoxide)
Authors: Cadosch Herbert , Eugster Conrad Hans 
Published: December 2004

AbstractNatürliches (+)‐Xanthophyllepoxid kann, nach Umwandlung in die diastereomeren furanoiden Epoxide, mit NiO2 zu ( − )‐Loliolid abgebaut werden. Semisynthetisches Xanthophyllepoxid gibt hauptsächlich Isololiolid. Daraus folgt, dass bei der säurekatalysierten Umlagerung der 5, 6‐Epoxide an C(5) praktisch keine Inversion eintritt und dass nat. (+)‐Xanthophyllepoxid die (3S, 5R, 6S, 3′R, 6′R)‐ und synth. Xanthophyllepoxid im wesentlichen die (3S, 5S, 6R, 3′R, 6′R)‐Konfigurationen besitzen.
Sur l'amino‐5‐benzoyl‐4‐méthyl‐3‐isoxazole: synthèse et transformation en dihydro‐6,8‐diméthyl‐3,8‐phényl‐4‐7H‐isoxazolo[5,4‐e]diazépin‐1,4‐one‐7
Authors: Jaunin Roland 
Published: December 2004

AbstractOn treatment with ammonia and benzaldehyde the benzalisoxazolone 3 does not give the aminoketone 7 as assumed by Speroni [1] but a product which has been shown to be identical with the enamine 8 prepared by Ried & Czack [4] from ethyl oximinoacetoacetate and benziminoethyl ether. Authentic aminoketone 7 was synthesized in a three‐step procedure starting from the aminonitrile 19. Conversion of 7 into the bromacetyl derivative 23 and subsequent treatment with hexamethylene‐tetramine yielded the isoxazolodiazepine 24. Methylation of 24 with diazomethane produced predominantly the N‐methyl derivative 1 along with a small amount of the O‐methyl compound 25.
Isokinetic Relationships in Alcohol Oxidation with Chromic Acid
Authors: Müller Paul , Perlberger Jean‐Claude 
Published: December 2004

AbstractThe activation parameters for the oxidation of 13 secondary alcohols with chromic acid have been determined. Application of a statistical treatment of Exner [9] shows that the reactions are isoentropic with an average entropy of activation (ΔS≠) of −24.0 e. u.
Neue Derivate der 7‐Amino‐cephalosporansäure. Über die Substitution der Acetoxygruppe durch aromatische Reste. Modifikationen von Antibiotica, 11. Mitteilung [1]
Authors: Peter Heinrich , Rodriguez Hermann , Müller Beat , Sibral Walter , Bickel Hans 
Published: December 2004

Abstract7‐Phenylacetamido‐3‐trifluoroacetoxymethyl‐ceph‐2‐em‐4‐carboxlic acid (7), which is easily produced from the iso‐cephalosporanic acid derivatives 4 or 6 by treatment with trifluoroacetic acid, reacts smoothly with ‘C‐nucleophiles’ to give derivatives of type 5 (Schema 1 and 2). Compounds 5 are converted into microbiologically active cephalosporins of type 8 (Table) by previously described methods.
Neue β‐Lactam‐Antibiotika. Über die Darstellung und Decarbonylierung von 3‐Formylcephem‐Verbindungen. Modifikationen von Antibiotica, 12. Mitteilung [1]
Authors: Peter Heinrich , Bickel Hans 
Published: December 2004

AbstractBenzhydrylic esters of 3‐unsubstituted cephem‐4‐carboxylic acids of types 9 and 10 (Scheme 2) are prepared by decarbonylation of esters of 3‐formylcephem compounds of type 2 with tris‐triphenylphosphine‐rhodium chloride. The preparation of the starting materials 2 and 5, as well as of the nucleus 13 is described.
Terpenoids Derived from Linalyl Oxide, Part 4. The oxidation of davanone. Isolation and synthesis of the davana ethers, sesquiterpenes of Artemisia Pallens
Authors: Thomas Alan F. , Dubini Renée 
Published: December 2004

AbstractThe photosensitized oxygenation of the β,γ‐unsaturated ketonic sesquiterpene, davanone, is described. Treatment of davanone epoxide with an acid ion exchange resin yields a stereoisomeric mixture of the davana ethers, sesquiterpenoids containing two reduced furan rings.
The [2,3] Sigmatropic Reaction of Acetonyl Allyl Ethers, a new method for preparing certain 2‐hydroxyketones
Authors: Thomas Alan F. , Dubini Renée 
Published: December 2004

AbstractA new [2] [3] sigmatropic rearrangement is described, enabling the conversion of acetonyl allyl ethers to 3‐hydroxy‐5‐en‐2‐ones.
Dediazoniations of Arene Diazonium Ions in Homogeneous Solution. Part VI: Solvolyses in 2,2,2‐trifluoroethanol/water mixtures and exclusion of a potential aryne mechanism
Authors: Burri Peter , Wahl George H. , Zollinger Heinrich 
Published: December 2004

AbstractThe rates and products of dediazoniation of benzenediazonium tetrafluoroborate in 2,2,2‐trifluoroethanol (TFE)/water mixtures has been determined. The results are not consistent with a mechanism in which TFE and water enter the rate‐determining part of the reaction as nucleophiles. The influence of the solvent composition on product ratios and rates is explained as a solvent effect, the formation of a (solvated) aryl cation being the rate‐determining part of the reaction. The magnitude of the preexponential factor of the Arrhenius equation is consistent with this interpretation. Since the solvolysis of p ‐chlorobenzenediazonium tetrafluoroborate in TFE yields no detectable m‐products, an aryne‐like mechanism is excluded.
On the Ring‐Expansion in Aromatic Nitrenes and Carbenes
Authors: Gleiter Rolf , Rettig Wolfgang , Wentrup Curt 
Published: December 2004

AbstractThe ring expansion, phenylnitrene (1) → azepinylidene (3) has been investigated using the CNDO/2 and Extended Hückel method. Both methods predict that the nitrene‐nitrogen of 1 is moving out of the molecular plane on the path of minimum energy. Whether an intermediate 2 is formed or not, the net charge during the reaction indicates that an interaction between the filled nitrene p‐orbital and an empty MO of the ring is important in lowering the transition state. The results are compared with experimental results of arylnitrenes and arylcarbenes. The rearrangement of tolylcarbenes to benzocyclobutene and styrene has been reexamined experimentally and interpreted in terms of the dynamics of the out of plane movement of the carbene during ring expansion.
Die Aufklärung der Isomerie‐Ursachen bei äquatorial koordinierten 2 : 1‐Arylazo‐Co(III)‐Komplexen mit Hilfe der kernmagnetischen Protonenresonanz
Authors: Schetty Guido , Steiner Eginhard 
Published: December 2004

Von methylgruppenhaltigen o, o‐′Dihydroxy‐diarylazo‐Liganden und ihren 1 : 2‐Co(III)‐Komplexen wurden die chemischen Verschiebungen (δ) der Methylprotonensignale im 1H—NMR.‐Spektrum bestimmt. Dabei wurde festgestellt, dass der Wert der chemischen Verschiebung von der Stellung der Methylgruppe am Arylrest und von ihrer relativen Lage zum koordinierten Stickstoffatom abhängt. Durch Vergleich der erhaltenen Werte, mit denen der entsprechenden methylgruppenhaltigen o, o′‐Dihydroxy‐diarylazomethine bzw. ihrer 1 : 2‐Co(III)‐Komplexe gelang es, Regelmässigkeiten zu finden, mit deren Hilfe als Isomerieursache bei 2 : 1‐Arylazo‐Co(III)‐Komplexen wechselweises Koordinieren der beiden Stickstoffatome (Nα/Nβ‐Isomerie) bewiesen und das koordinierte Stickstoffatom bezeichnet werden konnte.Ausserdem wurden an zwei Beispielen isomere 1 : 2‐Co(III)‐Komplexe nachgewiesen, in welchen das Metallin an das gleiche Stickstoffatom koordiniert ist, womit das frühere Postulat der Azo‐Hydroazon‐Tautomerie als eine weitere Isomerie‐Ursache in Metallkomplexen eine starke experimentelle Stütze erhalten hat.Die Beobachtung zweier isomerer 1 : 2‐Co(III)‐Komplexe eines o, o′‐Dihydroxyazomethins legt in diesem Fall das gleichzeitige Vorliegen der Azomethin‐ und der Chinonmethidstruktur nahe.
The Gas‐Solid Interface Heats of Adsorption of Simple Molecules on Microporous Carbons and on Graphitized Carbon Blacks, at Low Surface Coverage
Authors: Stoeckli Fritz 
Published: December 2004

AbstractThe heats of adsorption of nitrogen, argon, xenon, pentane, cyclohexane and benzene on a typical microporous carbon have been measured by gas‐solid chromatography. An overall comparison of the limiting heats of adsorption on active carbons and on graphitized carbon blacks shows a ratio of 1.6 between them. This is also the value of the ratio of the minima of the adsorption potentials. This result is discussed in terms of simple models for the shape of the micropores. Slot‐like pores give a better agreement.
Reversible Photochemistry, Absorption‐ and 1H‐NMR.‐spectra, and oxidation of the [2,2]metacyclophane‐1‐ene ⇄ 4,5,15,16‐tetrahydropyrene system
Authors: Naef R. , Fischer Ernst 
Published: December 2004

AbstractThe reversible photointerconversion in the above system was investigated in a wide range of temperatures and wavelengths of irradiation. The tetrahydropyrenes are obtainable only photochemically. The unmethylated and the mono‐methylated compound are oxidized with iodine quantitatively to 4,5‐dihydropyrene, even at −30°. This makes it possible to estimate the absolute concentration of the tetrahydropyrenes, and thereby their molar extinction coefficients and complete electronic absorption spectra. The quantum yields in both directions do not vary appreciably with the temperature, down to −190°. This is the first case in which the photocyclization yield of a cis‐stilbenelike compound is not attenuated on cooling, and reflects the special character of highly constrained structures. No emission was observed in solution. 1H‐NMR.‐spectra of both modifications of the dimethylated compound were taken. They support the structures assumed for both modifications, and also allow an estimate of their relative concentrations.
Reaction of Singlet Oxygen with 2‐Methylnorborn‐2‐ene, 2‐Methylidenenorbornane, and their 7,7‐Dimethyl Derivatives. The transition state geometry for hydroperoxidation
Authors: Jefford Charles W. , Boschung André F. 
Published: December 2004

AbstractThe dye‐sensitized photo‐oxygenation of 2‐methylnorbonr‐2‐ene (3), 2‐methylidene‐norbornane (4) and their 7,7‐dimethyl derivatives (5 and 6) has been studied. In all cases allylically rearranged hydroperoxides were formed, except that 4 also gave a little norbornanone (presumably from the dioxetane) and 5 gave some endo‐3,7,7‐trimethylnorbornan‐2‐one as a secondary photo‐product. It was found that the exo/endo attack ratios by singlet oxygen on 3 and 5 are 66 and 0.19. By exploiting the C (3) monodeuteriated derivatives, 4 and 6 showed ratios of 28 and 0.67.Rates of reactivity of the olefins 3 and 4 were compared to methylidenecyclopentane, 1‐methylcyclopentene and 1‐methylcyclohexene as monocyclic standards. Additionally, comparative rates between the 7,7‐dimethyl olefins and their parents were measured. When further comparison was made of the rate ratios partitioned for exo and endo attack, it was seen that oxygen experienced a 500‐ to 1000‐fold rate retardation on approach to the endo side of 3 compared to that for its monocyclic analogue. Exo rates between the parent norbornene 3 and its 7,7‐dimethyl derivative 5 showed a 250‐fold decrease. Although four times smaller than the difference reported for epoxidation, the evidence clearly pointed to a one‐step cyclic process as the rate determining step for photo‐oxygenation. The steric evidence, taken with the low values found for the intermolecular isotope effects of 1.14 ± 0.01 and 1.02 ± 0.01 observed for exo and endo‐3‐deuterio‐2‐methylidene‐norbornanes, permits the deduction that the transition state is largely dipolar. In the early stages of the addition bonding between one end of the oxygen molecule and the terminal vinyl carbon is advanced. At the same time positive charge is dispersed by hyperconjugation between the central carbon atom and the allylic carbon‐hydrogen bond. At a later stage the anionic oxygen atom abstracts the loosened allylic hydrogen atom to create the hydroperoxide. No evidence for the formation of a discrete perepoxide intermediate was obtained.
Organic Phosphorus Compounds 67. The exchange Cleavage of dialkylaminomethylphosphines with aryl and diarylphosphines [1]
Authors: Kaska William C. , Maier Ludwig 
Published: December 2004

AbstractInteraction of dialkylaminomethyl‐substituted tertiary phosphines with primary or secondary phosphines results often in the cleavage of a PC bond and the formation of PP bonds. Thus treatment of Ph2PCH2NEt2 with Ph2PH at 180° yields Ph2PPPh2 and HNEt2, and interaction of PhP(CH2NEt2)2 and PhPH2 at 150° results in the formation of (PhP)5, (PhP)4 CH2, HNEt2 and CH3NEt2.
The Thermal 2 + 2‐Addition of N‐(2‐Phenylallyl), N‐(3‐phenylally)‐toluenesulfonamide: Stereochemical and kinetic evidence for a diradical intermediate
Authors: Oppolzer Wolfgang 
Published: December 2004

AbstractDurch Thermolyse der trans‐ und cis‐Bis‐styryl Derivate 1a und 1b erhält man unabhängig von der Konfiguration des Ausgangsmaterials die Produkte 2 und 3 im gleichen Verhältnis. Die Verbindungen 1a, 2 und 3 lassen sich unter den Reaktionsbedingungen ineinander überführen. Diese Resultate sprechen für einen reversiblen Cycloadditionsprozess unter Beteiligung des diradikalischen Zwischenproduktes 4. Eine der Addukt‐Bildung vorgelagerte rasche cis/trans‐Isomerisierung 1b → 1a verläuft offensichtlich über das gleiche Diradikal. Übereinstimmungsgemäss erfolgt die cis/trans‐Isomerisierung des Mono‐styryl Derivates 5 zu 6 wesentlich langsamer als die Isomerisierung 1b → 1a.
Synthesis of New Xanthones, I
Authors: Pinto Madalena M. , Polónia Joaquim 
Published: December 2004

AbstractCondensation of salicylic acid and C‐methylphloroglucinol gave the already known 1,3‐dihydroxy‐2‐methylxanthone (1) along with two new compounds: 1,3‐dihydroxy‐4‐methylxanthone (2) and a second one tentatively presented as being 1,3‐dihydroxy‐2‐methyl‐4‐(2‐hydroxybenzoyl)xanthone (3). The UV., IR., NMR, and mass spectra for the two first compounds are reported and their structures discussed on the basis of δ‐values for H(2), H(4), CH3(4) and CH3(2). The UV. and IR. spectra for the third compound are reported too.
Etude par RMN. de polyaminocarboxylates de terres rares, III. Hydroxyéthyliminodiacétates de praséodyme
Authors: Chastellain François , Merbach André E. 
Published: December 2004

Abstract1H—NMR. has been used to study the chemistry of the hydroxyethyliminodiacetate complexes of praseodymium in aqueous solution. The ligand exchanges by spontaneous dissociation of the metal‐bis‐hydroxyethyliminodiacetate (1:2 complex) and of the metal‐bis‐hydroxyethyliminodiacetate hydroxocomplex, by acid catalysed dissociation of the 1:2 complex, and by a bimolecular process involving the free ligand and the 1:2 complex or the ternary hydroxo‐complex. The ligand exchange rate constants are given and the mechanisms discussed.
The Synthesis of Spiro[tetrahydroisoquinoline‐piperidines] and related compounds
Authors: Berney Daniel , Jauner Theodor 
Published: December 2004

AbstractThe reaction of 3,4‐dimethoxyphenethylamine with some cyclic aminoketones in the presence of polyphosphoric acid afforded 1‐spiro‐tetrahydroisoquinolines. A two‐step procedure starting from veratrylamine and amino‐ketones gave 3‐spiro‐tetrahydroisoquinolin‐4‐ones. The Schmidt rearrangement of 5,6‐dimethoxy‐3‐spiro‐indan‐1‐ones yielded 4‐spiro‐tetrahydroisoquinolin‐1‐ones.
Varianten im Zuckerteil des Streptozotocins
Authors: Gassmann Niklaus , Stoos Fred , Meier Arthur , Eldin Helali Salah , Hardegger Emil 
Published: December 2004

AbstractWir beschreiben die Synthese von krist. Analogen des Streptozotocins, welche sich von 6‐Amino‐D‐glucose, D‐Glucosaminol, D‐Glucamin, D‐Galactosamin, D‐Arabinamin, D‐Mannamin und D‐Galactamin ableiten. Die meisten der krist. Präparate wurden als Acetylderivate charakterisiert.