bluuebunny/crossref_metadata_2025_split huggingface dataset:
6‐Methyl‐Δ8,9‐ergolen‐8‐carbonsäure, ein neues Ergolinderivat aus Kulturen eines Stammes von Claviceps paspali STEVENSet HALL. 60. Mitteilung über Mutterkornalkaloide
Authors: Kobel H. , Schreier E. , Rutschmann J. 
Published: December 2004

AbstractAus Paspalurn‐Mutterkorn, das von zahlreichen, über die ganze Erde verteilten Fundorten beschafft worden war, konnten mehrere Hundert Stamme isoliert und unter geeigneten Standardbedingungen in Submerskultur gezüchtet werden. Auf Grund der Zusammensetzung des von den untersuchten Stammen produzierten Al‐ kaloidgemisches, liessen sich drei «chemische Rassen» H definieren. Zur ersten, weit‐ verbreiteten Rasse gehören 98°%yo aller untersuchten Stamme. Ihr sind auch die bereits bekannten Claviceps‐paspali‐stamme von CHAIN, TONOLO et al. [7] [8] und von GROGER et al. [9] zuzuordnen. Als Hauptalkaloide finden sich hier das Amid und das Methylcarbinolamid der Lysergsäure (IIa, b) und der Isolysergsäure (IIIa, b). Bei der zweiten, in Argentinien gefundenen, neuen Rasse bestehen 75 bis 80°% yo aller Alkaloide aus Ergobasin IIc und Ergobasinin IIIc. Die dritte, ebenfalls neue chemische Rasse, die bisher nur in Portugal gefunden wurde, bildet ein Gemisch fast ausschliesslich amphoterer Produkte, das neben Lysergsäure (I)zu über 70% aus der bisher unbekannten 6‐Methyl‐Δ8,9‐ergolen‐8‐carbonsäure (IV) besteht.
Metallindikatoren VII. Die Aciditätskonstanten und der Eisenkomplex des N,N′‐Äthylen‐bis‐(o‐hydroxyphenyl‐glycins (EHPG))
Authors: Anderegg G. , L'Eplattenier F. 
Published: December 2004

AbstractThe acidity constants of N, N′‐Ethylene‐bis‐(o‐hydroxyphenyl‐glycine) (= EHPG)have been determined. The stability constant of the 1:1 complex with trivalent iron has been determined from optical measurements of the equilibrium with trimethylene‐diamine‐tetraacetic acid. Among the studied ligands EHPG forms the stablest 1:1 complex with iron(II1). This red complex can be used in acid solution as indicator for the complexometric titration of iron.
Die Strukturen der mittleren Ringverbindungen VIII. Azacyclododecan‐hydrochlorid
Authors: Dunitz J. D. , Weber H. P. 
Published: December 2004

AbstractCrystals of azacyclododecane hydrochloride (a = 13.77, b = 5.07, c = 9.67 Å, α = 109°26′, β = 90°22′, γ = 101°16′) and hydrobromide (a = 13.53, b = 5.19, c = 9.45 Å, α = 99°40′, β = 83°57′, γ = 98°28′) are isomorphous, space group P1, Z = 2. The conformation of the 12‐membered ring has been established from three‐dimensional X‐ray analysis. It corresponds closely to the idealized model with 422‐symmetry, containing 8 syn‐clinal and 4 anti‐periplanar partial conformations.
Komplexone XXXVI. Reakinsenthalpie und ‐entropie bei der Bildung der Metallkomplexe der höheren EDTA‐Homologen
Authors: Anderegg G. 
Published: December 2004

AbstractComplexing agents of the type (−OOCCH2)N(CH2)nN(CH2COO−)2, with n values from 2 to 8, have been investigated. The stability constants and the heats evolved by formation of the 1:1‐complexes of Ca2+, Mg2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Pb2+, Hg2+ and La3+ have been determined. From the behaviour in complex formation reaction these cations can be divided into two groups. In the first one, including the A‐cations Ca2+, Mg2+, Mn2+, Cd2+, Pb2+ and La3+, the stability constants and −ΔH by formation of the 1:1‐complexes decrease rapidly when n is increased from 2 to 4. The second one contains all other metal ions investigated except Hg2+, and the drop in stability is observed between n = 4 and n = 5, whereas −ΔH slightly increases. Comparing the enthalpy values by formation of the complexes with cations of the first group of iminodiacetate and of EDTA (Table S), a considerable −ΔH increment is observed. The entropy gain by complex formation is approximately the same if the number of methylene groups in the chain connecting the two nitrogens is increased from 2 to 4. Replacement of one or two of these CH2− groups by 0 or S decreases generally the free energy and the enthalpy of complex formation to a great extent if new 5‐membered chelate rings are formed.
Die synchrone Fragmentierung von γ‐Amino‐cycloalkylhalogeniden 1. Teil. Die Solvolyse von 1‐Amino‐3‐brom‐adamantanen. Fragmentierungs‐Reaktionen. 10. Mitteilung
Authors: Grob C. A. , Schwarz W. 
Published: December 2004

AbstractThe stereochemical requirements for the concerted one‐step fragmentation mechanism of γ‐aminohalides (R2NCCC‐Hal) are discussed. 1‐Amino‐3‐bromo‐adamantane (12a) and its N‐methyl‐ and N,N‐dimethyl derivatives 12b and 12c, respectively, react by the concerted mechanism involving five atomic centers in the transition state. This is inferred from the exclusive formation of fragmentation products and from the enhanced reaction rates in «80%» ethanol as compared with the solvolysis rates of the homomorphous 1‐alkyl‐3‐bromo‐adamantanes 13a–c. The minimum values of the frangomeric accelerations for 12a, b and c are 30, 222 and 520 respectively. The fragmentation rates of the three 1‐amino‐3‐bromo‐adamantanes 12a–c increase in the order NH2 < NHCH3 < N(CH3)2.
Recherches sur la formation et la transformation des esters LVI. Action de l'acide sulfurique sur les aminoalcools
Authors: Cherbuliez Emile , Chapalay C. , Čolak‐Antić Sl. , Marszalek J. , Vallet L. , Rabinowitz J. 
Published: December 2004

AbstractBy heating an equimolecular mixture of an amino alcohol and H2SO4 during an appropriated time (half an hour to some hours) at 180–200°C under reduced pressure, the corresponding aminoalkyl sulfuric monoester is obtained in very good yield.
Cycloenantiomerie und Cyclodiastereomerie 2. Mitteilung. Über cycloenantiomere cyclo‐Hexaalanyle und ein cycloenantiomeres cyclo‐Diglycyl‐tetraalanyl
Authors: Gerlach H. , Owtschinnikow J. A. , Prelog V. 
Published: December 2004

AbstractThe cyclo‐hexaalanyls I, II and cyclo‐diglycyl‐tetraalanyl XXX have been prepared and investigated as examples of cycloenantiomeric compounds.
CLAISEN'sche Umlagerungen bei Allyl‐ und Benzylalkoholen mit Hilfe von Acetalen des N, N‐Dimethylacetamids. Vorläufige Mitteilung
Authors: Wick A. E. , Felix Dorothee , Steen Katharina , Eschenmoser A. 
Published: December 2004

AbstractThe preparative utility of the reaction between N, N‐dimethylacetamide‐dimethylacetal and allylic or benzylic alcohols to form N, N‐dimethylamides of γ, δ‐unsaturated acids or arylacetic acids is exemplified.
Fixation spontanée de la biotine à une protéine dans le Sérum humain
Authors: Vallotton M. , Hess‐Sander U. , Leuthardt F. 
Published: December 2004

AbstractBiotin has been found to be bound spontaneously and irreversibly by a protein fraction from human serum. The nature and characteristics of this fraction are studied with the help of dialyse‐equilibration and gel‐filtration on Sephadex G‐200.
Methyläther von Carotinoiden. Konfiguration des Azafrins
Authors: Müller H. , Karrer P. 
Published: December 2004

AbstractDie Herstellung von Methyläthern des Xanthophylls, Zeaxanthins, Capsanthins und Azafrins wird beschrieben, und es wird zur Frage der Konfiguration des Azafrins Stellung genommen.
Die Strukturen zweier 1:2‐Chromkomplexe von o, o′‐Dihydroxydiaryl‐trans‐azo‐Farbstoffmolekeln
Authors: Grieb Rita , Niggli A. 
Published: December 2004

AbstractThe crystal structure determinations of two pyridinium salts of 1:2‐chromium complexes formed by o,o′‐dihydroxy‐trans‐azo molecules show that the structure of the anions corresponds to the DREW‐PFITZNER arrangement [2], as postulated by G. SCHETTY [1] for cases where the ligands form five‐ and six‐membered rings with the metal ion. The correct structure formulae are given (cf. formulae I and II); as the refinement of both structures is still going on, further details (such as bond lengths and bond angles) will be published in Z. Krist.
Alkaloid‐Studien LII. Die Alkaloide aus Vallesia dichotoma RUIZet PAV
Authors: Walser A. , Djerassi Carl 
Published: December 2004

AbstractA total of 28 indole and dihydroindole alkaloids have so far been isolated from the bark or leaves of Vallesia dichotoma RUIZ et PAV. All but seven of these alkaloids have been characterized largely through the combined use of UV.‐, IR.‐ and NMR.‐spectroscopy as well as mass spectrometry. Their structures are listed together with other data in a table.
Zur Kenntnis der Hexaalkylbenzole. 5. Mitteilung. Über die Struktur der Dienaddukte des Hexaäthylidencyclohexans
Authors: Hopff H. , Kormany G. 
Published: December 2004

AbstractThe diadduct of hexaethylidenecyclohexane with maleic acid anhydride is shown to have a linear structure, giving anthracene and anthracene derivatives by dehydrogenation and decarboxylation.
Étude de composés d'addition des acides de LEWIS. XXIV. Mise en évidence par absorption infrarouge de l'ion mésitoylium dans H2SO4 concentré et l'oléum
Authors: Oulevey G. , Susz B. P. 
Published: December 2004

AbstractThe existence of the mesitoyl ion in solutions of mesitoic acid in concentrated H2SO4 and in oleum has been confirmed by infrared absorption spectra which show the characteristic 2190 cm−1 band already found in some addition compounds of mesitoic acid and mesitoyl chloride with LEWIS acids.
Recherches sur la formation et la transformation des esters LVIII. Sur la réaction de l'isothiocyanate de phényle avec quelques diols
Authors: Cherbuliez Emile , Marszalek J. , Rabinowitz J. 
Published: December 2004

AbstractBy reacting phenylisothiocyanate with several diols (ranging from 1,3 to 1,10 diols) at temperatures between 65–140°C for 2 to 14 hours in the presence of pyridine, thiocarbamylated derivatives of the diols are produced.
Autoxydation N2‐substituierter Methylhydrazine; Beeinflussung der Cu‐ & Fe‐Katalyse durch Proteine, Desoxyribonucleinsäure (DNS) und EDTA
Authors: Aebi H. , Dewald Beatrice , Suter Hedi 
Published: December 2004

Abstract1. Autoxidation of natulan and other methylhydrazine derivatives has been investigated by WARBURG'S direct manometric method. These compounds are relatively stable in a heavy‐metal‐free environment at pH 7.0, but are rapidly oxidised if a suitable catalyst is added.
Über den Mechanismus der Trypsin‐katalysierten Ester‐Hydrolyse: Modellversuche an Substraten
Authors: Gemperli Margrit , Hofmann Werner , Rottenberg Max 
Published: December 2004

AbstractAt both alkaline and neutral pH, tosyl‐L‐arginine ethyl ester hydrolyzes slower than benzoyl arginine ester, in disaccordance with the rules of inductive effects. Glycine and sarcosine esters however behave «normally», the tosyl derivatives reacting faster than the benzoyl. Tosyl‐L‐arginine esters are better substrates for trypsin than the corresponding benzoyl‐L‐arginine esters. It is concluded that the mechanism of trypsincatalyzed ester hydrolysis (deacylation) is fundamentally different from both neutral and alkaline hydrolysis.
Elektronenspinresonanz‐Untersuchungen von VO2+‐Komplexverbindungen in wässeriger Lösung II
Authors: Wüthrich K. 
Published: December 2004

AbstractComplex formation between vanadyl(IV) ion and Tiron, and sulfosalicylic acid respectively, has been investigated by means of electron paramagnetic resonance (e.p.r.) and optical spectroscopy. The 1:1‐ and 1:2‐complexes are distinguishable by the position of the absorption maxima in the optical absorption spectrum as well as by the parameters of the e.p.r. spectrum. There is no evidence for the existence of stable hydroxo‐complexes. The influence of the ligands on the vanadium nuclear hyperfine splitting constant in the e.p.r. spectrum is discussed in terms of spin polarization.
Stereochemie von Betanidin und Isobetanidin. 8. Mitteilung. Zur Konstitution des Randenfarbstoffes Betanin
Authors: Wilcox M. E. , Wyler H. , Dreiding André S. 
Published: December 2004

AbstractThe base exchange of betanidin and isobetanidin with 5,6‐dihydroxy‐2,3‐dihydroindole‐2R‐carboxylic acid (named R‐Cyclodopa, III) led to the formation of enantio‐isobetanidin and enantio‐betanidin, respectively. The enantiomers exhibited rotatory dispersion curves which were the mirror images of those of betanidin and isobetanidin. Thus it is shown that, in agreement with our proposed structure for betanidin, there exists in the molecule another, and only one other, asymmetric centre in addition to that present at C2, and furthermore, that isobetanidin differs from betanidin only in its configuration at this second centre (C15).
Harze mit Einschlusshohlräumen von Cyclodextrin‐Struktur
Authors: Solms J. , Egli R. H. 
Published: December 2004

AbstractA mixture of alpha‐, beta‐, and gamma‐cyclodextrins is cross‐linked with epichlorhydrin in alkali, giving a stable resin with glyceryl bridges between the cyclodextrin units. The resin forms specific inclusion complexes with many compounds. Isotherms of this process have been determined in aqueous solutions with benzaldehyde, aniline, p‐ and o‐nitrophenol, pyridine, butyric acid, iodine in potassium iodide, Congo red, methylorange, and methylene blue. For comparison isotherms have also been determined with the same substances for a commercial cross‐linked dextran without inclusion properties. The data illustrate a considerable ability of the cyclodextrin resin to form inclusion compounds.
Konstellation und Solvolysegeschwindigkeit der 1‐Decalyl‐p‐toluolsulfonate
Authors: Grob C. A. , Tam S. W. 
Published: December 2004

AbstractThe NMR.‐spectra of the four 1‐decalols and of their p‐toluenesulfonates have been determined. They are in agreement with accepted configurational assignments. Low‐temperature NMR.‐spectra of the cis‐1‐decalols indicate the predominance of conformation 7a in the case of the cis‐cis isomer m.p. 93° and a conformational equilibrium 8a⇄8b in the case of the cis‐trans isomer m.p. 55°.
Über die Chemie des Vitamins K. 2. Mitteilung. Totalsynthese und Stereochemie von trans‐ und cis‐(7′R, 11′R)‐Phyllochinon und verwandten Verbindungen
Authors: Jackman L. M. , Rüegg R. , Ryser G. , von Planta C. , Gloor U. , Mayer H. , Kofler M. , Isler O. , Schudel P. 
Published: December 2004

AbstractThe synthesis of trans‐ and cis‐(7′ R,11′ R)‐phylloquinone, trans‐ and cis‐menaquinone‐2, trans‐ and cis‐(7 R,11 R)‐phytol, and related compounds is described. Natural phylloquinone, isolated from alfalfa, is shown to possess the 2′,3′ ‐trans configuration.
Reaktionen mit Mikroorganismen. 14. Mitteilung [1] Reduktion von stereoisomeren Dekalonen‐(1) und einigen verwandten bicyclischen und tricyclischen Ketonen durch Curvularia falcata
Authors: Acklin W. , Prelog V. , Schenker F. , Serdarević B. , Walter P. 
Published: December 2004

AbstractRacemic, stereoisomeric decal‐1‐ones and several related bicyclic and tricyclic ketones have been reduced microbiologically with high stereospecificity by Curvularia falcata (TEHON) BOEDIJN. The constitution, and the relative and absolute configuration, of the products have been determined.
Experimentelle Beiträge zum MILLS‐NIXON‐Effekt I: Magnetische Kernresonanzspektren von 5‐Hydroxyindan und 6‐Hydroxytetralin 17. Mitteilung zur Kenntnis der Azokupplungsreaktion [1]
Authors: Koch W. , Zollinger Hch. 
Published: December 2004

Abstract5‐hydroxyindane and 6‐hydroxytetralin and their respective anions have been investigated by proton magnetic resonance spectroscopy. The results indicate that by forming the anion of 5‐hydroxyindane, the increase of electron density is the greatest at position 6, in agreement with its abnormal reactivity (Mills‐Nixon effect [2]).
Über eine neue allgemeine Synthese von 3,3‐disubstituierten 2,3,4,5‐Tetrahydro‐1H‐(benzo[b]1,4‐diazepin)‐2‐onen durch Ringerweiterung 3,3‐disubstituierter 1‐(o‐Aminophenyl)‐azetidin‐2‐one
Authors: Nicolaus Bruno J. R. , Bellasio Elvio , Pagani Giuseppe , Mariani Luigi , Testa Emilio 
Published: December 2004

AbstractEs wird über eine intramolekulare Umamidierung berichtet, welche in guter Ausbeute von den viergliedrigen 3,3‐disubstituierten 1‐(o‐Aminophenyl)‐azetidin‐2‐onen (V) durch Ringerweiterung zu den siebengliedrigen 3,3‐disubstituierten 2,3,4,5‐Tetrahydro‐1H‐(benzo[b]1,4‐diazepin)‐2‐onen (VII) führt. Neben der Synthese wird über die chemischen und physikalisch‐chemischen Eigenschaften dieser neuen Verbindungen, über deren IR.‐ und NMR.‐Spektren sowie über einige ihrer Umsetzungen ausführlich berichtet. Der mutmassliche Mechanismus dieser Umlagerung wird diskutiert. Diese Synthese stellt zugleich den ersten allgemeinen Weg zur einfachen Darstellung der bis heute noch nicht beschriebenen 3,3‐disubstituierten 2,3,4,5‐Tetrahydro‐1H‐(benzo[b]1,4‐diazepin)‐2‐one (VII) dar.
Kobalt(III)‐Komplexe von N, N, N′, N′‐Tetrakis‐(β‐aminoäthyl)‐äthylendiamin (= «penten»)
Authors: Emmenegger F. P. , Schwarzenbach G. 
Published: December 2004

AbstractSeveral salts containing the cation Co(penten)3+, in which the hexamin «penten» (formula: page 625) acts as a sexadentate ligand, have been synthesized and characterized. Its optical antipodes have been separated in some of the salts (Fig. 4), and the rate of racemization studied. In strongly alkaline solution one of the 5 chelate rings slowly opens and Co(penten)OH2+ is produced (Fig. 1), to which a first proton can be attached at the terminal NH2‐group (→ Co(Hpenten)OH3+), and a second which converts the hydroxo‐complex into the aquo‐complex (→ Co(Hpenten)OH4+). The equilibria between Co(penten)3+, Co(penten)OH2+, Co(Hpenten)OH3+ and Co‐(Hpenten)OH24+ have been elucidated, and the kinetics of the ring opening and ring closing reactions have been studied. Ring opening and ring closure take place with retention of configuration. It proved impossible to open two of the chelate rings of Co(penten)3+. Cristalline salts with cations of the general formula Co(penten)X3−λ or Co (Hpeten)X4−λ, with Xλ−  OH−, H2O, F−, Cl−, Br−, J−, SCN−, NO2,− and CO32−, have been obtained and characterized (Fig. 1, 2, 7 and Table 1).
Metallionen und H2O2. IV. Über Struktur und Aktivität der den H2O2‐Zerfall katalysierenden Cu2+‐Komplexe. II. Einfluss der Zahl der freien Koordinationsstellen
Authors: Sigel H. , Müller U. 
Published: December 2004

AbstractThe Cu2+ chelates of the bidentate ligands 2,2′‐bipyridine (I; [2]), N, N′‐diglycyl‐1,5‐diaminopentane (VI), ethylenediamine (II; [2]), glycine (V) and pyrophosphate (III; [2]) are found–parallel to the spectrochemical series–to be more active in catalysis of H2O2 decomposition than the chelates of the terdentate ligands–antiparallel to the spectrochemical series–iminodiacetic acid (IX), glycylglycine (VIII), 2, 2′‐diaminodiethylamine (VII) and 2, 2′, 2″‐terpyridine (IV; [2]), the activity decreasing in the given series. If all four coordination positions of Cu2+ are engaged (e.g. complex with N, N′‐di‐(2‐aminoethyl)‐ethylenediamine (X)) the complex is inactive. The catalytic activity of the Cu2+‐chelates is parallelled by the tendency to form ternary peroxo complexes.
Hydrolyse und Alkoholyse von Reaktivfarbstoffen: II. Hydrolyse von Monochlortriazin‐Farbstoffen. 2. Mitteilung über reaktionsmechanistische Untersuchungen an Reaktivfarbstoffen
Authors: Datyner A. , Rys P. , Zollinger Hch. 
Published: December 2004

Abstract
The kinetics of the hydrolysis of three monochlorotriazine reactive dyes have been determined in alkaline buffer solutions at 60°, 80° and 98° (ionic strength I = 0.0625).
The kinetic results as well as diffusion measurements in aqueous solution indicated that these dyes form aggregates at dye concentrations at 6 · 10−4, but practically not at 6·10−6 moles/l.
The reaction order with respect to hydroxyl ions has been determined. The influence of general base concentration was negligible.
Substitutions‐ und Eliminationsreaktionen an Aluminiumoxid: 1α‐ und 1β‐Benzoyloxy‐Δ2‐cholesten und 3β‐Chlor‐Δ1‐cholesten
Authors: Mühle H. , Orosz E. , Tamm Ch. 
Published: December 2004

AbstractThe formerly discribed [1] unknown substance CHT 208, which was obtained as side product when 3β‐benzoyloxy‐Δ1‐cholestene (3) was treated with ‘neutral’ activated alumina in an unpolar solvent, has been recognized as consisting of ca. 67% 3β‐hydroxy‐Δ1‐cholestene (6) and of ca. 33% 3β‐hydroxy‐Δ1‐cholestene (4) (molecular compound 2:1). Analogous treatment of 3β‐chloro‐Δ1‐cholestene (5) with alumina yielded the same mixture of the allylic alcohols 4 and 6 as substitution products and of Δ1,3‐cholestadiene (2) as elimination product in equal amounts.
Chemische Aspekte der Penicillin‐Allergie: die direkte Bildung der Penicilloyl‐Determinanten aus Penicillin
Authors: Schneider C. H. , De Weck A. L. 
Published: December 2004

AbstractThe aminolysis of two penicillin‐like compounds which cannot form penicillenic acid has been studied:

6‐Aminopenicillanic acid (which is highly immunogenic) reacts directly with ε‐amino groups at pH 7,4 under CO2‐free conditions; the possible role of its polymerisation in this reaction remains to be studied.
6‐Dinitrophenylamino‐penicillanic acid reacts with εamino groups at pH 7,4 as fast as benzylpenicillin and other penicillins. Its immunogenicity in the rabbit is similar to that of benzylpenicillin.
Un substrat pour le dosage chimique de la rénine
Authors: Roth M. , Reinharz Anja 
Published: December 2004

AbstractA fluorogenic renin substrate, N‐CBO‐L‐prolyl‐L‐phenylalanyl‐L‐histidyl‐L‐leucyl‐L‐leucyl‐L‐valyl‐L‐tyrosyl‐L‐seryl‐β‐naphthylamide, has been synthesized. Upon incubation at pH 5,6 with renin and an excess of the auxiliary enzyme aminopeptidase M, it gives rise to β‐naphthylamine at a rate related to the quantity of renin.
Die Kristallstruktur von 1,4‐trans‐Cyclohexan‐dicarbonsäure
Authors: Dunitz J. D. , Strickler P. 
Published: December 2004

AbstractCrystals of 1,4‐trans‐cyclohexane‐dicarboxylic acid are monoclinic, a = 5.60 Å, b = 9.63 Å, c = 8.05 Å, γ = 107°14′, space group P21/b (first setting), with 2 centrosymmetric molecules in the unit cell. The structure has been solved by direct methods and refined by full‐matrix least‐squares analysis of three‐dimensional intensity data. The mean CCC‐angle in the cyclohexane ring is found 112.0°. The conformation of the carboxylic group in various acids is discussed.
Die sterischen Bedingungen der Fragmentierungsreaktion I. Teil. Stereoisomere 3‐Chlortropane. Fragmentierungsreaktionen, 14. Mitteilung
Authors: Bottini A. T. , Grob C. A. , Schumacher E. , Zergenyi J. 
Published: December 2004

AbstractThe steric requirements for the synchronous fragmentation of γ‐aminohalides as previously postulated have been confirmed by a study of the solvolysis of stereoisomeric 3β‐ and 3β‐chloro‐tropanes and ‐nortropanes. 3β‐chloro‐tropanes (7 a) and 3β‐chloro‐nortropane (7 b), which fulfil the stereoelectronic requirements, undergo quantitative fragmentation in 80 vol.% ethanol. They react 1.35 × 104 and 1.35 × 103 times, respectively, as fast as the ‘homomorphous’ exo‐3‐chloro‐bicyclo[3.2.1]octane (12 a). Fragmentation therefore takes place by the synchronous mechanism.
Eine vielstufige Verteilungsapparatur
Authors: Signer R. , Arm H. 
Published: December 2004

AbstractA method of countercurrent distribution described ten years ago has been improved to get better resolution. Retaining the principle of fast establishment of liquid‐liquid equilibrium without emulgation, the rotating aggregate of separating chambers is not held horizontal, but inclined at an angle of 45°. The light mobile phase flows in every chamber as a thin layer over the heavy stationary phase. The separation of mixtures is analogous to that in a chromatographic column. The number of chambers can be easily increased to several hundred without complicating the handling of the apparatus. Another advantage consists in the complete absence of emulgations, even with systems or components that emulgate very easily. The apparatus can be operated under exclusion of oxygen.
Gas‐chromatographische und massenspektrometrische Untersuchung von Vitamin‐B6‐Trimethylsilderylderiveten
Authors: Richter W. , Vecchi M. , Vetter W. , Walther W. 
Published: December 2004

AbstractPyridoxine and pyridoxal are suitable for gas‐chromatographic analysis after conversion into their trimethylsilyl derivatives. Silylation proceeds rapidly and quantitatively, pyridoxal reacting in its hemiacetal form. The mass spectra of both derivatives are discussed.