bluuebunny/crossref_metadata_2025 huggingface dataset:
Syntheseversuche in der Griseofulvinreihe. 5. Mitteilung. Zur Synthese von (−)‐ und (+)‐Griseofulvin und ihrer Diastereomeren
Authors: Brossi A. , Baumann M. , Burkhardt F.
Published: December 2004

Rac. epigriseofulvic acid (II) has been resolved and (‐)‐ and (+)‐epigriseo‐fulvin (III) have been synthesized. Epimerisation of (‐)‐ and (+)‐III and separation of the diastereomeric mixtures afforded (‐)‐ and (+)‐griseofulvin (I) respectively. The chemotherapeutic activity of (+)‐I in vitro is practically identical with that of the natural antibiotic whereas the activity of its (‐)‐enantiomer is negligible.
Zur Kenntnis des Kohlenstoffringes. 76. Mitteilung. Acetolyse und spontane Zersetzung des Cyclodecyl‐p‐toluolsulfonates
Authors: Prelog V. , Küng W. , Tomljenovíć T.
Published: December 2004

Solid cyclodecyl p‐toluenesulfonate decomposes spontaneously at room temperature into p‐toluenesulfonic acid and cis‐cyclodecene. Pure cyclodecyl p‐toluenesulfonate gives by acetolysis a mixture of 80% trans‐ and 20% cis‐cyclodecene. The non‐classical, transannular course of these eliminations has been investigated by using starting material labeled with 14C. By systematic degradation of the cyclodecenes obtained it has been found that the amount of transannular hydride shifts in products of spontaneons decomposition differs considerably from that in products of acetolysis. These results explain the disturbing discrepancies observed in earlier experiments, in which partly decomposed cyclodecyl p‐toluenesulfonate must have been used.
O, N‐substituierte Hydroxylamine. 2. Mitteilung. Synthese und Eigenschaften der O‐(Phenylakyl)‐hydroxylamine (Untersuchungen über synthetische Arzneimitteln II)
Authors: Nicolaus Bruno J. R. , Pagani Giuseppe , Testa Emilio
Published: December 2004

Es wird über Synthese, chemische und physikalisch‐chemische Eigenschaften von O‐(Phenylalkyl)‐hydroxylaminen berichtet. Die Hydrochloride derjenigen Basen, in welchen die Hydroxylamingruppierung und der Phenylkern durch zwei C‐Atome getrennt sind, sind merkwürdigerweise unbeständig und lagern sich spontan bei Zimmertemperatur zu einem Ammoniumsalz und stickstoffreien Verbindungen um. Letztere wurden zum Teil gas‐chromatographisch getrennt und identifiziert. Es entstehen: aus O‐(1‐Methyl‐2‐phenyl‐äthyl)‐hydroxylamin‐hydrochlorid: Ammonium‐chlorid, Propiophenon (72%) und Methylbenzylketon (28%); aus O‐(2‐Phenyl‐äthyl)‐hydroxylamin‐hydrochlorid: Ammoniumchlorid und 2,5‐Diphenyl‐1, 4‐dioxan; aus O‐(1‐Methyl‐2‐phenyl‐äthyl)‐N‐methyl‐hydroxylamin‐hydrochlorid: Methylaminhydrochlorid, Proprophenon (59,4%) und Methyl‐benzyl‐keton (40,6%); aus O‐(2‐Phenylpropyl)‐hydroxylamin‐hydrochlorid: Ammoniumchlorid, Acetophenon (90,4%), Propiophenon (8,6%) und Methyl‐benzyl‐keton (1,0%).
Die Struktur des Fulvoplumierins
Authors: Albers‐Schönberg G. , v. Philipsborn W. , Jackman L. M. , Schmid H.
Published: December 2004

The stereochemistry of fulvoplumierine has been deduced from the proton‐magnetic‐resonance spectra of the natural product and 6‐ethyl‐fulvene as a model compound.
Über Isomeriefälle bei 1:2‐Kobaltkomplexen der o‐Carboxy‐o′‐amino‐azoreihe
Authors: Schetty G.
Published: December 2004

It has been shown that o‐carboxy‐o′‐amino‐azo‐dyestuffs analogous to the o‐carb‐oxy‐o′‐hydroxy‐azo‐dyestuffs form isomeric 1:2‐cobalt complexes which would support the observed rule, which states that stereoisomers are formed only by 6‐6‐ring complexes.
Pyrolyse von Aromaten. 1. Mitteilung. Biphenyl
Authors: Gäumann Tino , Rayroux J.‐M.
Published: December 2004

The products of the pyrolysis of light and heavy biphenyl are molecular hydrogen (or deuterium respectively), benzene, terphenyl and quaterphenyl. Several kinetic ways are discussed to explain the activation energy of 66 ± 8 kcal/mole for the decomposition of biphenyl, its isotope effect and the isomeric distribution of the terphenyls (10%, o, 48% m, 42% p) and quaterphenyls (1%oó, 11% om′, 8% op′, 29% mm′, 39% mp′, 9,12% pp′) produced. There are not enough data to allow a clearcut decision of their way of formation.
Das Trennrohr XXIV. Darstellung von 18O2 und das Problem der Anreicherung von 17O
Authors: Clusius Klaus , Schleich Kuno
Published: December 2004

Die Trennung eines polynären Isotopengemisches durch Thermodiffusion wird am Beispiel des Sauerstoffs theoretisch und experimentell behandelt. Wegen des Vorhandenseins von drei Sauerstoffisotopen liegen sechs Molekelsorten 16O2, 16O17O, 16O18O, 17O2, 17O18O, 18O2 vor. Es wird vorausgesetzt, dass sich an den 1000° K heissen Trennrohrdrähten aus Platin‐Iridium isotope Gleichgewichte wie

im Vergleich mit den von der Thermodiffusion und der Konvektion abhängigen Gleichgewichten in einer Trennrohranlage schnell einstellen. Diese Voraussetzung wird empirisch geprüft, wobei noch kontrolliert wird, dass innerhalb des Massenspektrometers keine Verschiebung eines vorgegebenen Häufigkeitsverhältnisses der Sauerstoffmolekelsorten erfolgt.

Das Verhalten des hexanären Gemisches der Sauerstoffmolekeln wird unter zwei Voraussetzungen für den Thermodiffusionsfaktor α untersucht. Einmal soll α in «erster Näherung» proportional (mi − mk)/m sein, wobei m die mittlere Massenzahl bedeutet. Bei der «zweiten Näherung» wird α proportional (mi − mk)/mi + mk angesetzt. Die auf einer Horizontalstrecke dx im Temperaturfeld auftretende Entmischung bewirkt längs eines vertikalen Trennrohrelements dζ eine proportionale Entmischung. Indem man die Nullstelle von ζ so wählt, dass die atomare 17O‐Konzentration maximal wird, lässt sich unter Umgehung einer Integration die Konzentrationsverteilung der sechs Molekelsorte als Funktion der Längskoordinate ζ der Trennanlage berechnen. Die Eigenschaften der sich so ergebenden Kurven werden diskutiert. Der Wert von ζ lässt sich empirisch bestimmen.

In einer Trennanlage A von 40 m Gesamtlänge wurden aus Sauerstoff mit 1,5 bis 2,5% 18O‐Gehalt 12 Liter Konzentrat mit 30 bis 55% 18O gewonnen. Diese wurden in einer zweiten Trennanlage B von 24 m Gesamtlänge weiterverarbeitet. Dabei traten am schweren Ende einige Liter 18O2 mit einer Reinheit von 99,6% aus, während am leichten Ende an 18O abgereicherter Sauerstoff anfiel, der zur Anlage A zurückkehrte. Auf diese Weise konnte das äusserst schwierig anzureichernde Mittelisotop 17O die Anlage B nicht verlassen, so dass es bis zu einer Maximal‐konzentration von 6,2% angereichert wurde. In diesem Stadium wurde der Versuch abgebrochen und die Verteilung der Molekelsorten längs der Trennanlage gemessen. Es ergab sich schon für die erste Näherung eine ausgezeichnete Übereinstimmung mit der Theorie, die durch die zweite Näherung noch merklich verbessert wurde.

Aus der Theorie ergeben sich Richtlinien, um das Isotop 17O in Form von Kohlenoxid zu gewinnen. Dazu wird vorgeschlagen die Mischmolekel 14N15 als Hilfsgas zu verwenden, die vom isosteren 12C17O durch Thermodiffusion im Trennrohr nicht abgeschieden werden kann, während 12C16O am leichten und 12C18O am schweren Ende austreten müssen. Die Notwendigkeit einer Voranreicherung des 17O und der störende Einfluss des 13C und des BOUDOUARD‐Gleichgewichts werden in ihren qualitativen Auswirkungen besprochen.
Protonenresonanzspektrosopie und Steroidstruktur. II. Die Lage der C‐18‐ und C‐19‐Methylsignale in Abhängigkeit von den Substituenten am Steroidgerüst
Authors: Zürcher R. F.
Published: December 2004

The proton NMR spectra of 265 steroids of known structure have been recorded for 0,1M solutions in deuterochloroform and the positions of the signals of the 18‐and 19‐hydrogen atoms have been measured. The additional chemical shifts due to various substituents at many different positions of the steroid skeleton are compiled in a table. With its help most chemical shifts of the 18‐ and 19‐hydrogen atoms of these and unknown steroids may be computed with an accuracy of ± 0,015 ppm. An example show how to calculate the chemical shifts. The physical basis of teh influences due to substituents and double bond, as well as the reasons for the generally small deviations from the calculated chemical shifts, are reviewed and illustrated. The additional chemical shifts due to identical funcitonal groups in equivalent positions, i. e. in approximately the same steric relation to one of the tertiary methyl groups, are collected in a table. Possible reason for teh variation of these additional chemical shifts within sets of identical functional functional groups in equivalent positions are discussed. The table furnishes interesting insights into the conformation of certain steroids and shows the average values and deviations one has to reckon with if the chemical shifts on methyl groups in non‐steroidal compounds due to functional groups in corresponding positions to those in steroids are to be computed.
Les spectres de RMN. et de masse de quelques dérivés chlorés du méthylbutane et de substances avoisinantes
Authors: Willhalm B. , Thomas A. F. , Stoll M. , Hawkins E. G. E.
Published: December 2004

The NMR. and mass spectra of some chlorinated methylbutenes, methylbutanes and related substances derived from isobutane have been measured. Plausible mechanisms for the principal fragmentation processes have been obtained by deuteration studies.
Das Trennrohr XXVI. Die Konzentrationsverteilung polynärer isotoper Gemische im geschlossenen Trennrohr
Authors: Clusius Klaus , Varde Eva
Published: December 2004

Aus dem System von Differentialgleichungen für die Verteilung eines isotopen Gemisches im Trennrohr: magnified image ergibt sich in guter Näherung magnified image, wobei mi die Masssenzahl der Komponente i und ζ die Längskoordinate der Trennanlage, deren Einheit zweckmässig experimentell bestimmt wird, bedeutet. Dio Molenbrüche an der Nullstelle (ζ = 0) der Trennrohranlage γ20, γ20,—γ, die als Integrationskonstanten auftreten, sind aber im allgemeinen unbekannt und müssen aus der Bedingung, dass die Masse jeder Komponente erhalten bleiben soll, bestimmt werden. In dieser Arbeit wind beschrieben, wie die Integrationskonstanten γio (i = 1,2,—n) berechnet werden können, indem vom Grenzfall verschwindender Trennrohrlänge, bei der die γio, mit den Molenbrüchen in der Ausgangsmischung γia identisch sind, ausgegangen wird. Diese γia‐Werte dienen als erste Näherungswerte für ein Trennrohr endlicher, aber kurzer Länge. Durch Iteration werden die γio so lange verbessert, bis die Massenerhaltungsintegrale zu den anfänglichen γia‐Werten fürhren. Das Verfahren wird schrittweise für grössere Trennrohrlängen entsprechend fortgesetzt.
Spectres RAMAN et d'absorption infrarouge de quelques oléfines ozonées. III. Spectres des produits d'ozonation des anétholes cis et trans et de l'estragole, des O‐méthylisoeugénol et O‐Méthyleugénol, et du styrène
Authors: Briner E. , Christol Mme C. , Christol H. , Fliszár S. , Rossetti G.
Published: December 2004

On a examiné les spectres IR. et RAMAN de solutions d'olkfinés, ozonkés de manière à contenir des concentrations suffisamment élevées en produits d'ozonation: aldéhydes et ozonide (produit principal).
Lunidin und Lunidonin, zwei neue Alkaloide aus Lunasia amara BLANCOvar. repanda (LAUTERB. et K. SCHUM.) LAUTERB
Authors: Rüegger A. , Stauffacher D.
Published: December 2004

From the bark of Lunasia arnara BLANCO var. refmnda (LAUTERB. et K. SCHUMM) LAUTERB. (New Guinea) were isolated apart from the known Rutaceae alkaloids hydroxylunidine (I), hydroxylunacridine (II), lunacrine (111) and lunacridine (IV) two new crystalline alkaloids. One of these differs from I only by the absence of the tertiary hydroxyl group in the side‐chain and was therefore named lunidine (V). The other one (VIII) is a ketone also obtained by oxidation of the hydroxyl group of lunidine. We therefore named it lunidonine.
Zuordnung von optisch aktiven Absorptionsbanden in trigonalen Komplexen des dreiwertigen Chroms und Kobalts
Authors: Bürer Th.
Published: December 2004

The comparison of circular dichroism or rotatory dispersion data leads to a classification of trigonal coordination compounds (symmetryD3,C3) of trivalent chromium and cobalt according to the size of the metal‐ligand‐metal ring (five‐ or six‐membered ring, without or with n‐bonding). Within these classes an assignment of the optically active absorption bands is proposed.
Umwandlung von Cardenoliden durch Mikroorganismen. V. Hydroxylierung und Dehydrierung durch Psilocybe semperviva HEIMet CAILLEUX und Psilocybe mexicana HEIM. 11. Mitteilung über Reaktionen mit Mikroorganismen
Authors: Weiss‐Berg E. , Tamm Ch.
Published: December 2004

Digitoxigenin was transformed by growing cultures of Psilocybe mexicana HEIM to 7β‐hydroxydigitoxigenin, 3‐dehydrodigitoxigenin, 3‐dehydro‐7β‐hydroxydigitoxi‐genin and to digoxigenin. Incubation of digitoxigenin with Psilocybe sewperviva CAILLEUX ct HEIM yielded Digoxigenin as main product. 3‐Dehydrodigitoxigenin was oxygenated to 3‐dehydro‐7β‐hydroxydigitoxigenin by P. mexicana and hydrogenated to digitoxigenin and hydroxylated to digoxigenin by P. semperviva. Strophanthidin was reduced to strophanthidol by P. semperviva.
Organische Phosphorverbindungen XXIV Darstellung und Struktur von ketten‐ und ringförmigen Polyphosphinen
Authors: Maier Ludwig
Published: December 2004

The new triphosphine CH3P[P(C6H5)2]2, m. p. 130–134º, has been prepared in high yield by the interaction of (C6H5)2PH and CH3P[N(CH3)2]2. This triphosphine is cleaved by CH3J and Br2. With sulfur it yields an adduct of the probable structure CH3P[P(S)(C6H5)2]2, m. p. 163,5–166º.
Über Tribenzyl‐D‐glucofuranoside, eine neue Gruppe von Heilmitteln auf dem Kohlenhydratgebiet. 1. Mitteilung über verätherte Kohlenhydrate
Authors: Huber G. , Rossi A.
Published: December 2004

The synthesis of ethyl‐3, 5, 6‐tri‐O‐benzyl‐D‐glucofuranoside, a new pharmacologically active compound, and of a series of its homologues (at C‐1) and acyl or O‐alkyl derivatives (at C‐2) is described. With the help of nmr‐spectroscopy the configuration and possible ring conformation of some of the anomers are discussed.
Cu2+‐Komplexe von Polyaminosäuren in wässeriger Lösung Katalytische Aktivität (H2O2‐Zerfall) und Struktur
Authors: Sigel H. , Blauer G.
Published: December 2004

The decomposition of H2O2 (8 · 10−3M) catalyzed by complexes of Cu2+ (4 · 10−4M) with various oligomers and polymers of glycine, L‐lysine or L‐glutamic acid was investigated in aqueous solution in the pH range 5–11, at 24°C and at low ionic strength. Previous investigations have shown that the decomposition of H2O2 is catalyzed by Cu2+‐complexes capable of forming Cu2+‐peroxocomplexes.

With increasing pH the catalytic activity of Cu2+‐complexes with glycine or glycylglycine (1:1) increases while the activity of Cu2+‐complexes with tri‐ or tetraglycine (1:1) is comparatively small at higher pH values apparently because in the latter cases the coordination positions of the copper become progressively occupied by the peptides. This interpretation is in accordance with the pH‐dependence of the light‐absorption spectra of the latter complexes.

Cu2+‐complexes with poly‐α, L‐lysines of various molecular weights (molar ratios Cu2+: lysine residues = 1:15) have a catalytic activity comparable to or higher than that of the complex Cu2+‐ethylenediamine (1:1), indicating two available coordination positions for formation of peroxo‐complexes. On the other hand, the system Cu2+‐L‐lysine (1:15) showed no significant activity probably because all coordination positions at the Cu2+ are occupied by lysine. Despite the excess of ligand groups over Cu2+ in the polylysine systems the structure of this polyamino acid apparently does not allow its full coordination with these groups under the conditions investigated. Two adjacent chelating ε‐amino groups are considered as the main ligand groups of the polymer to each copper ion.

The Cu2+‐poly‐α, L‐glutamic acid complex examined (Cu2+: glutamic acid residues = 1:5) shows comparatively little activity. In this case, absorption spectra indicate formation of hydroxo‐complexes at higher pH.

Besides the effects of structure, the electrostatic fields of the charged polyelectrolytes polylysine or polyglutamic acid are also considered to affect the rates of catalysis.
Herzwirksame Glykoside aus der weissen Meerzwiebel. Konstitution des Scilliphäosids und des Glucoscilliphäosids. 55. Mitteilung über Herzglykoside [1]
Authors: von Wartburg A. , Kuhn M. , Huber K.
Published: December 2004

Scilliphaeoside (I), C30H42O9, and glucoscilliphaeoside (III), C36H52O14, represent two minor glycosides which occur in the bulbs of the white sea onion or squill [Scilla (= Urginea) maritima (Baker) L.]. Glucoscilliphaeoside is easily converted into scilliphaeoside and D‐glucose by selective enzymatic cleavage with β‐glucosidases (e. g. strophanthobiase). Acid hydrolysis splits glucoscilliphaeoside into anhydroscilliphaeosidin (IV) and L‐scillabiose (= β‐D‐glucosyl‐L‐rhamnose), scilliphaeoside yields the same anhydro‐aglycone IV and L‐rhamnose. The true genin scilliphaeosidin (VI), C24H32O5, has now been gained by a combined oxidative and hydrolytic cleavage of the rhamnose residue of scilliphaeoside. By chemical evidence and spectroscopical data scilliphaeosidin is characterized as a trihydroxy‐Δ4‐steroid of the bufadienolide type. The assumed locations of the three hydroxylic functions at C‐3, C‐12 and C‐14 are established by permanganate degradation of the lactone ring of di‐O‐acetyl‐scilliphaeosidin (VII) to the etianic acid derivatives XIII and XIV, which are also available from digoxigenin. These correlations prove the structure of scilliphaeoside (I) as 12β‐hydroxy‐proscillaridin A, glucoscilliphaeos de (III) representing 12β‐hydroxy‐scillaren A.
Synthese von Salm‐Calcitonin, einem hochaktiven hypocalcämischen Hormon. Vorläufige Mitteilung
Authors: Guttmann St. , Pless J. , Huguenin R. L. , Sandrin Ed. , Bossert H. , Zehnder K.
Published: December 2004

A total synthesis of salmon calcitonin is described. The C‐terminal nonapeptide amide 24–32 was coupled with the heptapeptide 17–23. The resulting hexadecapeptide amide 17–32 was reacted with the heptapeptide 10–16 to give the tricosapeptide 10–32. This was condensed with the N‐terminal nonapeptide 1–9, yielding the protected dotriacontapeptide amide 1–32. After removal of the protective groups and purification by gel‐filtration the free peptide obtained exhibited the physical, chemical and biological properties of the natural hormone. Its hypocalcaemic activity (ca. 3500 MRC U/mg) is 20–30 times higher than that of porcine or human calcitonin.
Zur Frage der Deprotonierung primärer und sekundärer Aminogruppen beim Kobaltieren von o‐Hydroxy‐o′‐amino (bzw. alkyl‐amino)‐azofarbstoffen vom Typus Phenyl‐azonaphtalin
Authors: Schetty G.
Published: December 2004

Phenyl‐azo naphthalene dyestuffs, which are substituted in o and in o′ position by hydroxy and amino (or alkylamino) groups, have been metallised with agents releasing either CoII ions or CoIII ions, the 1:2 complexes formed being examined by means of electrophoresis and alkalimetric titrations. The amino or alkylamino groups are deprotonised only if they are in the naphthalene radical, or, if present in the benzene radical they are acidified by electrophilic substituents. Metallising with CoII ions yielded usually 1:2 CoIII complexes. With one particular dyestuff, however, a 1:2 CoII complex was obtained; it is assumed that this is due to a relatively lower oxidation potential of this dyestuff.
Beiträge zur Chemie der Si‐N‐Bindung, XIX [1]. Die thermische Stabilität von Silicium‐Stickstoff Verbindungen
Authors: Fink Walter
Published: December 2004

The thermal stability of some types of silicon‐nitrogen compounds was investigated.
Thermische Reaktionen im Massenspektrometer Modellreaktionen zur Untersuchung thermischer Umalkylierungen. 11. Mitteilung über das massenspektrometrische Verhalten von Stickstoffverbindungen
Authors: Veith H. J. , Hesse M.
Published: December 2004

During the introduction of an organic compound into the mass spectrometer thermal reactions can take place before the ionisation process, thus changing the structure of the compound. On the basis of known experimental results the following reactions, which are independent of electron bombardment are discussed: decarboxylation, dehydration, loss of alcohols, decarbonylation, decomposition of carboxylic esters, retro aldol reaction and similar processes, retro DIELS‐ALDER reaction, isomerisation, disproportionation, hydrogenolysis‐dehydrogenolysis, transalkylation, dimerisation, and pyrolysis of quaternary nitrogen containing compounds. Finally, the results of novel model reactions concerning thermal transalkylation are discussed.
Untersuchungen über die Konformation des cyclischen Hexapeptids cyclo‐Glycyl‐L‐prolyl‐glycyl‐glycyl‐L‐prolyl‐glycyl mittels protonenmagnetischer Resonanz und Parallelen zum Cyclodecapeptid Gramicidin S. 14. Mitteilung über homodet cyclische Polypeptide [1] [2]
Authors: Schwyzer R. , Ludescher U.
Published: December 2004

The first proton magnetic resonance observations made with cyclic hexapeptides suggested the presence of two types of amide protons: one participating in intramolecular hydrogen bonds and more strongly shielded, the other exposed to the solvent and less shielded (SCHWYZER, et al. 1964 [2]). This was taken as evidence for the β‐type structure proposed for homodetic cyclic peptides with 2 · (2n + 1) amino acid residues in the ring (SCHWYZER [4]), n = 1, 2, 3 … These conclusions have now been confirmed by studies on the solvent dependence of chemical shifts in cyclo‐glycyl‐prolyl, cyclo‐glycyl‐prolyl‐glycyl‐glycyl‐prolyl‐glycyl (III) and gramicidin S. On passing from a typical amide proton acceptor solvent (hexadeuterodimethylsulfoxide or tetradeuteromethanol) to trifluoroacetic acid the solvent‐exposed protons become more shielded and the intramolecularly hydrogen bonded ones less so (Figure 5). The proposed β‐structure of the cyclodecapeptide gramicidin S (n = 2 in the above formula; HODGKIN & OUGHTON [8], crystalline state; SCHWYZER [9], in solution) which has recently been supported by side‐chain interaction studies (using a nuclear magnetic resonance marker) on the biologically active derivative, diphthalylgramicidin S (SCHWYZER & LUDESCHER [1]) as well as by other methods [6] [7], is thus additionally supported. Our experiments, as well as those of KOPPLE [11], strongly favor a β‐structure for simple cyclohexapeptides in solution; this is particularly true for compound III which is, with respect to the two proline residues, a model of gramicidin S.
Elektromotorisches Verhalten von Glaselektroden in flüssigem Ammoniak
Authors: Baumann W. M. , Simon W.
Published: December 2004

Glass electrodes behaving as protodes or alkali cation electrodes in aqueous systems respond to the protonated solvent in liquid ammonia at — 38°C and can be used to measure the activity of NH4+. Deviations in the response to the activity of NH4+ are shown to be due to an alkali metal function (alkaline error) of the glass electrodes. The selectivity of glass electrodes for different alkali metal cations changes drastically from water to liquid ammonia.
Ein Beitrag zu den Untersuchungsmethoden der Austauscherkinetik an Ionenaustauschern
Authors: Hermann H. , Ebersold J. , Gerber H. , Hügli F.
Published: December 2004

Die Kinetik eines Ionenaustauschprozesses wird mittels einer speziellen polarographischen Untersuchungsmethode untersucht. Die polarisierbare Hg‐Elektrode berührt die DONNAN‐Flüssigkeit im Zentrum der zylindrischen Ionenaustauschermembran. Das austauschende Ion, zugleich der Depolarisator, diffundiert radial in die Ionenaustauschermembran ein. Durch Vergleich der experimentell erhaltenen Konzentrations‐Zeit‐Diagramme mit den theoretischen Diagrammen, die sich aus den NERNST‐PLANK'schen Beziehungen ergeben, können die Diffusionskoeffizienten des Depolarisators bestimmt werden.

Mit dieser Methode wurde die Austauschreaktion von K+ gegen Cd2+ an einem Phenolsulfonsäureharz untersucht, und der Diffusionskoeffizient von Cd2+ im Harz wurde bestimmt.
Low Temperature Thermodynamics. The excess Gibbs function and the volumes of mixing for the system methane + propane at 90.68K
Authors: Stoeckli H. F. , Staveley L. A. K.
Published: December 2004

The excess Gibbs function Ge and the excess volumes of mixing Ve have been measured at the methane triple point (90.68 K) for the system methane+propane. They were compared with McGlashan's recent theory for mixtures of molecules of different sizes.
Die Glykoside der Wurzeln von Xysmalobium dilatatum Weimarck. 2. Mitteilung: Teilstruktur der Dilatoside. Glykoside und Aglykone, 328. Mitteilung
Authors: Meister L. , Stöcklin W. , Reichstein T.
Published: December 2004

The four dilatosides A, B, C and D (ester glycosides isolated from Xysmalobium dilatatum) differ from each other only in the sugar portion. They all contain the same aglycone: 12‐O‐acetyl‐17‐isolineolone (=12‐O‐acetyl‐17‐isodeacyl‐cynanchogenin) (6). Its mass spectrum is discussed. In dilatoside A (1) three molecules of D‐oleandrose (7) are linked to this aglycone, in dilatoside B (2) one D‐canarose (8) and two oleandrose units, in dilatoside C (3) two canarose and three oleandrose, and in dilatoside D (4) probably three canarose and two oleandrose units.
Weitere Cardenolide aus Ch'an Su. Über Krötengifte 37. Mitteilung
Authors: Höriger Niklaus , Živanov Dobrila , Linde Horst H. A. , Meyer Kuno
Published: December 2004

From the toad venom Ch'an Su digitoxigenin (I), periplogenin (IX), and sarmentogenin (XI) were isolated as well as the two new 14, 15 β‐epoxy‐cardenolides III and VI which — regarding their steroid nucleus — are corresponding to cinobufotalin and marinobufagin, respectively.
Mass Spectrometric Studies of Mono‐ and Di‐Haloacetylenes
Authors: Kloster‐Jensen Else , Pascual C. , Vogt J.
Published: December 2004

The mass spectra of the four monohaloacetylenes X‐CC‐H with X = F, Cl, Br, I and the six dihaloacetylenes X‐CC‐Y with X, Y = Cl, Br, I have been recorded. The dissociation energies of the carbon‐carbon triple bonds of these compounds have been determined from the appearance potentials of the CH+ and CX+ ions. The appearance potentials of the singly‐ and doubly‐charged molecular ions are also reported.
Konstitution der Bufotoxine. Über Krötengifte, 38. Mitteilung
Authors: Linde‐Tempel Hannelore O.
Published: December 2004

The structure of the so‐called ‘bufotoxines’ has been elucidated by enzymatic degradation.
Contribution à l'étude de la mésomérie, IX [1]. Système formé d'un atome à trois électrons et de n atomes à un électron chacun
Authors: Klement O. , Fauchère J. L.
Published: December 2004

Une simplification des calculs dans le cadre de la méthode de mésomérie, analogue à celles indiquées dans des mémoires antérieurs [1] et [2], est présentée pour un système à un atome à trois électrons et n atomes à un électron chacun.
Über das Hydrolysegleichgewicht von Phenylbutazon (Butazolidin®)
Authors: Schmid R. W.
Published: December 2004

Phenylbutazone (I) forms in aqueous and partially aqueous solution butylmalonic acid mono (N, N′‐diphenylhydrazide) (II) by a reversible reaction. The reaction rate and the position of equilibrium depend on the solvent but practically not on the pH. The temperature dependence is given for several media. Substituents affect the reaction rate when they are in 4‐position but not in 4′‐ or 4″‐position. Based on the kinetic data, a reaction mechanism is proposed. Methods for the analysis of I in mixtures with II are presented. The preparation of II is described.
Equilibres d'ionisation et photoréduction du vanadium(V) dans l'acide sulfurique concentré
Authors: Marcantonatos M. , Piguet R. , Monnier D.
Published: December 2004

By spectrophotometry of dilute solutions of V2O5 in concentrated sulfuric acid VVH2SO4 complexes are shown to convert slowly to VIV monomers. Spectral, kinetic and equilibrium studies on these solutions suggest that this conversion involves a photoreduction of VV to VIV dimeric species.
Vibrations de valence CH dans les hydrocarbures et les halogénures de butyle
Authors: Avanessoff M. , Gäumann T.
Published: December 2004

The valence vibrations CH and CD of a number of alkanes and of (CH3)3CX are studied using compounds deuterated in specific positions. For the methyl and the methylene groups an experimental model of group frequencies is proposed, which allows some general conclusions to be drawn concerning the assignation of the frequencies. The methyl group always shows a Fermi resonance between νs and 2δas in the region of 2930–2870 cm−1. In consequence the unperturbed νsCH3 frequency may be situated at ∽2915 cm−1 and the absence of a coupling with other groups can be checked. The vibrations of the methylene group adjacent to a methyl group have higher frequencies than those of CH2 groups further removed. The coupling of the methylene group with other groups is always strong and may amount to 10 cm−1. For a chain of methylene groups, the coupling is the larger the longer the chain; being relatively small for symmetrical modes (∽3 cm−1) for the antisymmetric mode. A correlation is found between protonated and deuterated groups which leads to isotope effects comparing well with recorded values.
Synthese von α‐Methylsordarose. Sordarin, 2. Mitteilung
Authors: Spichtig A. M. , Vasella A.
Published: December 2004

The structure of the sugar obtained by acid hydrolysis of the antibiotic Sordarin has been verified by a synthesis of the corresponding α‐methylglycoside.
Energy Profiles for Ring Formation‐ and Ring Opening‐Processes in the cis‐Stilbene‐4a,4b‐Dihydrophenanthrene System. An example of the feasibility of a process forbidden by the rules of orbital symmetry conservation
Authors: Muszkat K. A. , Schmidt W.
Published: December 2004

An Extended Hückel MO treatment of the system cis‐stilbene (I)‐4a, 4b‐dihydrophenanthrene (II) indicates that the concerted photocyclisation is a conrotatory process of the first excited electronic state. The activation energies for the photocyclisation and for the thermal ring opening and the ground state energy difference between I and II, as predicted by the present calculation, are in good agreement with the experimental findings. The observed effects of substituents on the photocyclisation quantum yields are satisfactorily accounted for by a general qualitative treatment and thus indicate that the photocyclisation takes place in the first excited state.
Beiträge zur Chemie der 4‐Hydroxyindol‐Verbindungen 10. Mitteilung über synthetische indolverbindungen [1]
Authors: Seemann F. , Wiskott E. , Niklaus P. , Troxler F.
Published: December 2004

Catalytic hydrogenation of 4‐benzyloxyindoles does not stop at the hydroxyindole stage, but slowly leads to the 4,5,6,7‐tetrahydro‐4‐ox‐indoles 3. Some procedures for the selective preparation of 4‐hydroxyindoles 2 are described. When 4‐benzyloxy‐3‐(1‐hydroxyimino‐ethyl)‐indole (4c) is warmed with trifluoroacetic acid, cleavage of the ether results as well as partial benzylation of the free hydroxyindole in the position 5 (5a, 5b); no Beckmann rearrangement is observed. Esters of 4‐benzyloxy‐indole‐2‐carboxylic acid are formylated with POCl3/dimethylformamide in the 7‐position to give 7a; in the corresponding dimethylamide, on the other hand, the formyl group enters the 3‐position to give 8. Both 4‐ and 7‐hydroxyindole are oxidized with Frémy's salt to the 4, 7‐quinone 13; on reduction this yields 4, 7‐dihydroxyindole 14, which is tautomerized by base‐catalysis to 5, 6‐dihydro‐4, 7‐dioxo‐indole 15. The course of the etherification of 4‐hydroxyindoles with epichlorohydrin and related compounds is described, and the resulting side‐chains are characterized by their NMR. spectra.
Weitere Untersuchungen über den Mechanismus der reduktiven Spaltung von Azoverbindungen
Authors: Schellenberġ M. , Mollet H.
Published: December 2004

The experimental results of our earlier investigation of the azodye bleach mechanism are interpreted in a revised manner. The reductive cleavage of methylorange by a dihydroquinoxaline proceeds in two steps. In the medium pH‐range the first step (production of the hydrazo derivative) is slower (and not faster, as considered before) than the second (reductive splitting of the hydrazo derivative). In strongly acid solution this relation is reversed.

The rate of disproportionation of the hydrazo derivative of methylorange is proportional to the concentration of the protonated hydrazo compound. For this reaction a two step mechanism is proposed in which a molecule of hydrazo compound is cleaved in a rate determining first step to an oxidizing particle and an amine molecule. In the following fast reaction the oxidizing intermediate attacks a second hydrazo molecule yielding methylorange and a further amine molecule. Based on this reaction sequence an azodye bleach mechanism is formulated which is able to explain the kinetics of the reductive cleavage of methylorange by a 1, 4‐dihydroquinoxaline at any pH value.

The azodye bleach mechanism is much more complex if the 1,4‐dihydroquinoxaline used is able to form a radical or to tautomerize. The resulting reaction kinetics are discussed.
Synthesen in der Carotinoid‐Reihe 23. Mitteilung Ein Beitrag zur Chromsäure‐Oxydation von Polyenen
Authors: Schwieter U. , Arnold W. , Oberhänsli W. E. , Rigassi N. , Vetter W.
Published: December 2004

Chromic acid oxidation of polyenes with terminal β‐ionylidene groups has been studied. A number of hitherto unknown and unexpected oxidation products has been isolated. A mechanism for these oxidations is discussed.
Synthese Aldosteron‐ähnlicher Corticosteroide. Racemisches 11‐Dehydroaldosteron (rac.‐18‐Oxo‐11‐dehydrocorticosteron) Über Steroide, 223. Mitteilung
Authors: Schmidlin J.
Published: December 2004

Racemic 11‐dehydroaldosterone (rac.‐18‐oxo‐11‐dehydrocorticosterone) is prepared starting from the 3, 3; 20, 20‐bisethylene acetal of the racemic 3, 20‐dioxo‐11β, 21‐dihydroxy‐Δ‐pregnene‐18‐oic acid‐(18 → 11β)‐lactone, an intermediate obtained previously in the first total synthesis of aldosterone. A cyclic 18(21)‐hemiacetal structure is deduced for the new corticosteroid from spectroscopic and chemical evidence.
Abschätzung der Alkali‐ und Erdalkali‐Ionenselektivität von elektrisch neutralen träger‐antibiotica («carrier‐antibiotica») und modellverbindungen
Authors: Morf W. E. , Simon W.
Published: December 2004

Using model calculations, the influence of coordination number, properties of ligand groups, dimension of the ligand, steric interactions, and solvent on the complexation of alkali‐ and alkaline earth metal cations by electrically neutral ligands (carrier antibiotics, model compounds) is discussed. Information is given on the molecular parameters needed to achieve a given ion selectivity in view of the use of such ligands as carriers in ion selective membranes.
Steroide und Sexualhormone 243. Mitteilung [1] die partialsynthese von 3‐o‐methyl‐20ξ‐7, 8‐dihydrobatrachotoxinin A
Authors: Graf W. , Gössinger Frl. E. , Imhof R. , Wehrli H.
Published: December 2004

The synthesis of 3‐O‐methyl‐20ξ‐7, 8‐dihydrobatrachotoxinin A (12) is described.
Über das Lipoxygenase‐«Lipoperoxidase»‐System in Cerealien: I. Untersuchung der reaktionsprodukte
Authors: Heimann W. , Schreier P.
Published: December 2004

Zusammenfassung. Nach Inkubation der durch Soja‐Lipoxygenase (E.C.1.13.1.13.) gebildeten Linolsäurehydroperoxide (LHPO) mit einem Hafer‐Acetontrockenpulver treten 13‐Hydroxy‐cis‐9, trans‐11‐octadecadiensäure und 9‐Hydroxy‐trans‐10, cis‐12‐octadecadiensäure auf. Durch Einsatz von [14C]‐LHPO wird nachgewiesen, dass es sich um Umsetzungsprodukte der LHPO handelt. Nach Hitzeinaktivierung bleibt die Umsetzung aus. Die Verbindungen wurden nach Veresterung, katalytischer Hydrierung und Oxydation als 13‐Oxo‐ bzw. 9‐Oxo‐stearinsäure‐methylester massenspektrometrisch identifiziert. Trennung und Reinigung erfolgten jeweils mittels präparativer Schichtchromatographie unter spektroskopischer Kontrolle (UV., IR.). Auf Grund der Ergebnisse kann auf die Beteiligung einer Peroxidase am enzymatischen LHPO‐Abbau in Hafer geschlossen werden. Die Beteiligung von Lipoxygenase und Peroxidase an der Biosynthese cis‐trans‐konjugierter Hydroxyfettsäuren wird diskutiert.
Heterogenität der Drosophila‐Aldolase und Hybridisierung mit Säugeraldolase 20. Arbeit über aldolasen
Authors: Brenner‐Holzach O. , Leuthardt F.
Published: December 2004

–1. FDP aldolase from pupae of Drosophila melanogaster is shown by the following findings to be a tetrameric molecule with two non‐identical subunits: (a) Disc electrophoresis on polyacrylamide gel in the presence of sodium dodecylsulfate yields a subunit molecular weight of 40000 (equal to that of rabbit muscle aldolase). (b) Hybridisations of drosophila aldolase with type C aldolase from rabbit and calf brain lead to a five‐membered set of isoenzymes.

2. The non‐identity of the subunits is suggested by the behaviour on isoelectro focussing. While rabbit muscle aldolase and human liver aldolase show five isoenzymes (hybrids from the non‐identical subunits), drosophila aldolase can be separated into three peaks only. This result may be interpreted in two ways: (a) The isoenzymes α4 and α3α′ are not separated from each other in the pH range 5‐‐8, neither are αα′3 and α′4. Or (b) α2 and α′2 are not split under the condition of isoelectro focussing and therefore 3 isoenzymes α4, α2α′2, and α′4 are obtained only.

(3) Isoenzyme I (supposedly mainly α4) and isoenzyme III (supposedly mainly α′4) are identical in the following respects: Michaelis constant, pH profile, FDP/F‐1‐P activity ratio, inactivation by carboxypeptidase A, disc electrophoresis on polaycrylamide and molecular weight. The only difference found between isoenzyme I and III is the specific activity: Isoenzyme I is nearly twice as active as isoenzyme III.

4. The fact that hybridisation between drosophila aldolase and type C aldolase from rabbit and calf brain yields a set of isoenzymes proves that interspecies hybridisation is possible between FDP aldolases from vertebrates and invertebrates. FDP aldolases from vertebrates and invertebrates seem to be homologous enzymes. Our results suggest that the conformation of aldolases remained relatively unchanged during evolution.
Photolyse von indazolen, benzisoxazolen und anthranilen in saurer Lösung Vorläufige Mitteilung
Authors: Georgarakis [2] M. , Doppler [3] T. H. , Märky M. , Hansen H.‐J. , Schmid H.
Published: December 2004

Indazoles and anthranils on irradiation with a mercury high‐pressure lamp in acidic solution (H2SO4/H2O or H2SO4/CH3OH) yield 2‐amino‐5‐hydroxy(or methoxy)‐benzaldehydes (acetophenones, respectively) as major products and 2‐amino‐3‐hydroxy (or methoxy)‐benzaldehydes (acetophenones, respectively) as minor products. Photolysis of benzisoxazoles in conc. sulfuric acid results in the formation of 2,5‐and 2, 3‐dihydroxybenzaldehydes (acetophenones, respectively). 5‐Methylindazoles form on irradiation in diluted sulfuric acid 2‐amino‐5‐methyl‐benzaldehydes.
Comment on the Chirality and Cotton Effects of Cyclic α‐Diketones: Revision of recent conformational assignments
Authors: Burgstahler Albert W. , Naik Nandkishor C.
Published: December 2004

A recent proposal [1] correlating the Cotton effects and dione chirality of various cyclic α‐diketones according to a skewed glyoxal model is held to require revision in the light of overriding evidence from molecular models and the effects expected from substituent chirality contributions.
Die Umwandlung von Penicillinen in Cephalosporine. Modifikationen von Antibiotika, 3. Mitteilung
Authors: Heusler K.
Published: December 2004

A new method for the degradation of the thiazolidine ring in penicillins is described. Penicillin V (8a), penicillin G (8b) and 6‐t‐butoxycarbonylaminopenicillanic acid (33) (BOC‐6‐APA) were converted via their acylazides and isocyanates (10 and 34) into 2,2,2‐trichloroethyl urethanes (11 and 35). Reductive removal of the trichloroethoxycarbonyl groups in an aqueous medium gave the 3‐hydroxy‐penam‐derivatives 13 and 36. The structure and various reactions of these carbinolamides are discussed in detail. An oxidative radical fragmentation (using lead tetraacylates and light) followed by thermal treatment transformed the 3‐hydroxy‐penam‐derivatives into the N‐formyl‐β‐lactam‐thio‐enolethers 27 and 37 in which the formyl group could be replaced by hydrogen. Reactions of the β‐lactam and thio‐enolether functions are described.

The BOC‐derivative 37 can be transformed into the isomeric compound 3, an intermediate in Woodward's total synthesis of cephalosporins.
Neue β‐Lactamsysteme aus Penicillinen. Modifikationen von Antibiotika, 5. Mitteilung [1]
Authors: Fechtig B. , Bickel H. , Heusler K.
Published: December 2004

3‐Isopropyl‐4‐thia‐2,6‐diazabicyclo[3.2.0]heptan‐7‐on (8), a potential intermediate for the synthesis of new β‐lactam antibiotics [5], was prepared from the urethanes 7a and 9 by reduction with zinc/acetic acid. The cyclic Schiff base 10, which constitutes an intermediate in this reaction, was prepared by reduction of 9 with CrCl2 and was further reduced to 8 with zinc/acetic acid.
Myrochromanol und Myrochromanon, zwei weitere Metaboliten von Myrothecium roridum Tode ex Fr. Verrucarine und Roridine, 25. Mitt.
Authors: Tamm Ch. , Böhner B. , Zürcher W.
Published: December 2004

From cultures of Myrothecium roridum Tode ex Fr. myrochromanol (1) and myrochromanone (3), two new substituted chromanes, have been isolated. Their structures as 2‐(1‐propenyl)‐4‐hydroxy‐6‐methyl‐chromane and 2‐(1‐propenyl)‐4‐oxo‐6‐methyl‐chromane respectively, have been determined using spectroscopic techniques and by degradation to 2‐hydroxy‐5‐methylbenzoic acid (6). The stereochemistry of 1 and 2 is deduced by NMR., CD. and by partial resolution ( Horeau method).
Massenspektrometrische Untersuchungen von Naturprodukten; Cardenolide
Authors: Brown Peter , Brüschweiler Fred , Pettit Georg R.
Published: December 2004

The mass spectrometry of cardenolides is briefly reviewed. Recent developments in the characterization of the cardiac glycosides by a combination of electron impact and field ionization methods are discussed, with emphasis on the information obtained regarding the sequence of monosaccharide residues in the case of oligosaccharide glycosides. Recent efforts to understand the detailed fragmentation behaviour of cardenolide aglycones in terms of their structure and substitution pattern are also discussed.
1‐Substituierte Cycloheptatrienverbindungen
Authors: von Bredow K. , Helferich G. , Weis C. D.
Published: December 2004

Cycloheptatriene reacts with acrylic esters, in the presence of catalytic amounts of tricarbonyl‐triphenylphosphine‐nickel, to yield a mixture of α‐cycloheptatrienyl‐propionic acid esters (2a) substituted in various positions. Methacrylic acid ester yields likewise α‐cycloheptatrienyl‐isobutyric acid ester (3a). Both types of ester mixtures undergo thermal isomerizations by 1,5‐hydrogen shifts to give mixtures which contain predominantly the (C‐1)‐substituted cycloheptatrienyl‐carboxylic acid esters (2a, 3a). Pure α‐(1‐cycloheptatrienyl) derivatives can be prepared from 2a and 3a. A detailed NMR. study of the ester mixtures before and after thermal isomerization shows the proportions of the various isomers in the mixture. The mechanism of the formation of 2a and 3a is explained in terms of a catalysed ene‐reaction of the primary formed 7‐substituted cycloheptatriene derivatives with subsequent consecutive 1,5‐hydrogen shifts.
Composés d'addition des halogénures de niobium(V) et de tantale(V). V. Stabilité relative des composés des chlorures avec quelques oxydes et sulfures organiques
Authors: Merbach A. , Bünzli J. C.
Published: December 2004

The adducts of niobium(V) and tantalum(V) chlorides with some aliphatic and cyclic oxides and sulfides, studied by NMR. spectroscopy in CHCl3, are found to have 1:1 stoechiometry, at room temperature and lower. In the thioxane complex TaCl5 · C4H8OS two species are present with the ligand coordinated by the sulfur atom or by the oxygen atom, respectively, in a proportion which has been determined. The thioxane adduct of niobium(V) chloride, however, is preferentially coordinated by the sulfur atom. There is also evidence for the species 2MCl5 · C4H8OS. The relative basicity of each donor atom in dioxane, thioxane and dithiane is calculated and discussed. In contrast to the nitrile adducts, whose stability was found earlier to be controlled by inductive factors, the steric factors are more important for the ether and sulfide adducts: MCl5 · Me2X is more stable than the corresponding MCl5 · Et2X (M = Nb, Ta; X = O, S). Both niobium(V) and tantalum(V) chlorides have a soft behaviour, but NbCl5 is a weaker Lewis acid than TaCl5 and shows also a softer behaviour.
Sigmatropic Reactions in Carbanions. I. The 5, 6‐dihydro‐2H‐pyran‐2‐ide cyclopropyl‐enolate rearrangement
Authors: Rautenstrauch V.
Published: December 2004

Lithiation of 5,6‐dihydro‐2H‐pyran (7) gives a mixture of dihydropyranyllithiums 14 and 2. 14 rearranges to 2, and 2 in turn undergoes a [1,4] sigmatropic shift to give the lithium cyclopropyl‐enolate 3. Lithiation of nerol oxide 6 gives the lithio derivative 24, which likewise undergoes [1,4] shifts to give cyclopropyl‐enolates 28 and 29.
Über Pyrrolizidinchemie. 11. Mitteilung [1]. Totalsynthese von (±)‐Platynecin
Authors: Viscontini M. , Buzek H.
Published: December 2004

1‐Methoxycarbonyl‐7‐oxo‐6,7‐dihydro‐5H‐pyrrolizin (I) bildet durch katalytische Hydrierung vorwiegend das (±)‐Lacton (II), dessen Konfiguration eindeutig bestimmt wurde. Reduktion mittels LiAlH4 wandelt dieses Lacton in (±)‐Platynecin (III) um, ohne Berührung der chiralen Zentren der Molekel. Die chemischen und physikalisch‐chemischen Eigenschaften des synthetisch erhaltenen Razemates stimmen mit jenen des natürlichen (−)‐Platynecins überein.
Photoinduced reactions of aryl‐2H‐azirines with carbonyl compounds. Preliminary communication
Authors: Giezendanner H. , Märky M. , Jackson B. , Hansen H.‐J. , Schmid H.
Published: December 2004

Irradiation of 3‐phenyl‐(4), 2‐methyl‐3‐phenyl‐(8), and 2,3‐diphenyl‐2H‐azirine (10), in benzene solution in the presence of aldehydes, yields the corresponding aryl‐3‐oxazolines. Photochemical reaction of 4 and 10 with carbon dioxide leads to the formation of 4‐phenyl‐ (15) and 2,4‐diphenyl‐3‐oxazolin‐5‐one (16), respectively.
Zur Photodimerisierung von 3‐Phenyl‐2H‐azirinen. Vorläufige Mitteilung
Authors: Gakis N. , Märky M. , Hansen H.‐J. , Schmid H.
Published: December 2004

Irradiation of 3‐phenyl‐2H‐azirine (2) in benzene solution with a high‐pressure mercury lamp yields 4,5‐diphenyl‐1,3‐diazabicyclo[3,1,0]hex‐3‐ene (4) and not 3‐phenylimino‐4‐phenyl‐1‐azabicyclo[2,1,0]pentane (1), as had been reported previously by others [2]. 2‐Methyl‐3‐phenyl‐2H‐azirine (3) yields on irradiation a 2:1 mixture of 2‐exo, 6‐exo‐ and 2‐exdo, 6‐exo‐dimethyl‐4,5‐diphenyl‐1,3‐diazabicyclo[3,1,0]hex‐3‐ene (2‐exo,6‐exo‐ and 2‐endo, 6‐exo‐5). Irradiation of 2,3‐diphenyl‐2H‐azirine (8) leads to the formation of 2,4,5‐triphenyl‐imidazole (9) and tetra‐phenylpyrazine (10). The suggested reaction path for the generation of 9 and 10 is shown in Scheme 2.
The Natural Occurrence of the Campholenyl Skeleton, Another «Non‐isoprenoid» Monoterpene System
Authors: Thomas Alan F.
Published: December 2004

In the essential oil of Juniperus communis L. (fruit), campholenic aldehyde and its epoxide have been identified, together with the corresponding alcohol and its acetate. This is the first time the natural occurence of 2‐(2,2,3‐trimethylcyclopent‐3‐en‐1‐yl)‐ethyl system is reported.
Circulardichroismus einiger A‐nor‐Steroide und verwandter Verbindungen
Authors: Snatzke G. , Lábler L. , Tamm Ch.
Published: December 2004

The Circular Dichroism (CD.) of several saturated and conjugated keto‐A‐nor‐steroids follows the known rules. Homochiral α,β‐epoxy‐cyclopentanones and ‐cyclohexanones give the same sign of the Cotton effect within the R‐band, whereas the K‐band CD. of the former has opposite sign to that at 300 nm. More examples for the application of the rule for the determination of the CD. of non‐coplanar conjugated lactones as well as α,β‐epoxy‐lactones are presented.
The Crystal Structure of Nonactin
Authors: Dobler M.
Published: December 2004

An X‐ray crystal structure investigation of the macrotetrolide antibiotic nonactin is reported. The shape of the molecule is discussed with special reference to the conformational changes involved in passing from free nonactin to the K+‐complex.