bluuebunny/crossref_metadata_2025 huggingface dataset:
Katalytische Effekte bei den Reaktionen von 2, 4‐Dinitrofluorbenzol mit Benzylamin und N‐Methylbenzylamin in Benzol. 6. Mitteilung über nucleophile aromatische Substitutionsreaktionen
Authors: Bernasconi C. F. , Zollinger Hch.
Published: December 2004

The rates of reaction of 2,4‐dinitrofluorobenzene with benzylamine and with N‐methylbenzylamine have been measured in benzene solution, with and without the addition of pyridine or 1, 4‐diaza‐bicyclo[2.2.2]octane (DABCO) as catalyst.

Both reactions are catalyzed by the reacting amine, by pyridine and by 1, 4‐diaza‐bicyclo[2.2.2]octane.

Whereas the dependence on base concentration is linear in the case of N‐methyl‐benzylamine, the rate constants are curvilinearly related to base concentration in the reaction with benzylamine. Steric effects are shown to be responsible for this different behaviour, which is easily understood in terms of the two‐step intermediate mechanism (eq.1) for nucleophilic aromatic substitutions.

Part of the pyridine catalysis has to be attributed to a medium effect, as can be shown directly in the reaction involving benzylamine.

The sensitivity of both reactions to base catalysis is much greater than that of the reaction of piperidine with 2, 4‐dinitrofluorobenzene, but is found to be considerably smaller than in the reaction of p‐anisidine with the same substrate, thus suggesting a correlation between the basicity of the reacting amine and the sensitivity of the reaction to base catalysis.
Zur Frage der Koordinationsweise von Chromkomplexen aus dem Azofarbstoff 1‐Amino‐2‐hydroxy‐naphtalin‐4‐sulfonsäurepiperidid →→ 1‐Phenyl‐3‐methyl‐5‐pyrazolon
Authors: Schetty G. , Beffa F.
Published: December 2004

On chroming the dyestuff 1‐amino‐2‐hydroxy‐naphthalene‐4‐sulfonic acid piperidide → 1‐phenyl‐3‐methyl‐5‐pyrazolone, only one 1:2 chromium complex is formed. This fact as well as the absorption spectra and the great stability of the complex indicate that the complex must be coordinated in the Drew‐Pfitzner arrangement, and that the sandwich arrangement must be excluded. Since the steric structure of the 1:2‐complex is already preformed in the adequate 1:1‐complex, our results disprove the conclusions presented by IDELSONet al. [1] [3].
Fluoreszierende Stoffe aus Roten Waldameisen der Gattung Formica (Ins. Hym.). 5. Mitteilung. Isolierung von Lumazin‐Derivaten aus Ameisenmännchen
Authors: Schmidt G. H. , Viscontini M.
Published: December 2004

Aus Männchen der Ameisenart Formica polyctena FOERST. wurden mit Hilfe chromatographischer Verfahren an Cellulosesäulen Lumazin, Lumazin‐6‐carbonsäure, Isoxantholumazin, 6‐Methyl‐8‐ribityl‐isoxantholumazin sowie zwei weitere, noch nicht identifizierte Isoxantholumazinderivate isoliert. Die ersten vier Lumazine wurden durch Vergleich mit authentischen synthetischen Produkten identifiziert.
Dipolmomente 1, 6‐überbrückter [10]‐ Annulene
Authors: Bremser W. , Grunder H. T. , Heibronner E. , Vogel E.
Published: December 2004

The dipole moments of 1, 6‐bridged [10]‐annulenes of type I (X = CH2, O, NH) and of bromo derivatives with X = CH2, O
magnified image
are in agreement with the previously established structure of these compounds if a partial moment of approximately 0,8 D is assigned to the non‐planar π‐electron system.
Weitere Alkaloide aus Aspidosperma limae Woods
Authors: Pinar M. , Schmid H.
Published: December 2004

Aus der Stammrinde von Aspidosperma limae Woods. wurden die drei neuen, einander sehr nahe verwandten Alkaloide 11‐Methoxylimatin (5), Limatinin (3) und 11‐Methoxylimatinin (7) kristallisiert abgetrennt. Die Struktur und die Chiralität dieser Alkaloide wurden bestimmt; sie entsprechen dem Aspidospermatidin‐Typus.
Optische Rotationsdispersion von Indolalkaloiden der Yohimban‐, Corynanthean‐ und Quebrachamin‐Gruppe
Authors: Klyne W. , Swan R. J. , Dastoor N. J. , Gorman A. A. , Schmid H.
Published: December 2004

It has been shown that optical rotatory dispersion curves can be used to determin‐ the absolute stereochemistry at C(3) of indole alkaloids of the yohimban and corynane thean types. This is dependent on the absence of strong chromophores other than that of the aromatic system.
Exposition et développement simultanés de plaques cristallines de bromure d'argent. II
Authors: Fernandez‐Garcia J. G. , Steiger R. , Guillemin M. , Boissonnas C. G.
Published: December 2004

Thin monocristalline sheets of silver bromide have been developed at the contact of a platinum wire connected with a battery. It is shown by electron diffraction that the developed silver grains are composed of silver crystals with a diameter of approximately 150 Å. Autoradiography proves that most of the reduced silver ions are located in a thin superficial layer of the crystalline sheet of silver bromide.
Synthese von 7α‐Methylöstron. Über Steroide, 210. Mitteilung
Authors: Wieland P. , Anner G.
Published: December 2004

Various ways of converting testosterone and dehydroisoandrosterone into 7α‐methylestrone are described. The best method starts from dehydroisoandrosterone and gives 7α‐methylestrone in a total yield of about 24% by weight.
Études sur les matières végétales volatiles. CCII. Synthèse d'aldéhyde phénylacétique à partir du styrolène
Authors: Naves Yves‐René
Published: December 2004

On treatment of styrolene between 30 and 40°C with performic acid, phenylglycol monoformate is produced.
Synthese von geminal methylierten 4‐Chlorbutylaminen
Authors: Currell D. , Grob C. A. , Tam S. W.
Published: December 2004

The syntheses of 4‐chloro‐1‐dimethylamino‐4‐methyl‐pentane (1) and 4‐chloro‐1‐dimethylamino‐2,2,4‐trimethyl‐pentane (2a) are described.
Stabile Dihydroflavine und quartäre Flaviniumsalze Studien in der Flavinreihe, 12, Mitteilung
Authors: Dudley K. H. , Hemmerich P.
Published: December 2004

Flavohydroquinones (leucoflavins) protected by acetylation at N(5) have been alkylated to give derivatives substituted at oxygen and/or nitrogen functions in the pyrimidine part of the nucleus. Removal of the protecting group under oxidizing conditions gave N(1),N(3)‐, O(2),N(3)‐ or O(2), O(4)‐dialkyl‐flavoquinonium salts. The N(1)‐substituted type could be reduced to give free flavohydroquinones stable in air, which in turn could be further alkylated at N(5). On oxidation the N(5)‐alkyl groups are readily removed through the radical intermediate. The N(10)‐alkyl groups may be split from the flavoquinonium salt if they are activated (e. g. ‐CH2COOR). The O‐alkyl groups are readily hydrolysed under neutral or slightly acid conditions whereas a basic medium provokes deprotonation at the 8‐CH3 group and concomitant irreversible dimerization. The potential importance of these models for elucidating the mechanism of flavin‐dependent biological dehydrogenation is mentioned.
Die sterischen Bedingungen der Fragmentierungsreaktion III. Teil. Stereoisomere 4‐, 5‐ und 7‐Decahydrochinolyl‐toluolsulfonate Fragmentierungsreaktionen, 16. Mitteilung
Authors: Grob C. A. , Kiefer H. R. , Lutz H. J. , Wilkens H. J.
Published: December 2004

In a heterolytic fragmentation reaction of the type a‐b‐c‐d‐X → a‐b + c=d + :X the geometry of the d‐X bond and that of the electron‐donating group a relative to the b‐c bond are critical. This follows from a study of solvolysis rates and products of stereoisomeric 1‐methyl‐4‐, ‐5‐ and ‐7‐decahydroquinolyl p‐toluenesulphonates in 80 Vol.% ethanol.
Die Cardenolide der Samen von Mansonia altissima, A. CHEV. Glykoside und Aglykone, 286. Mitt.
Authors: Allgeier H. , Weiss Ek. , Reichstein T.
Published: December 2004

The seeds of Mansonia altissima A. Chev. were found to contain ca. 1% cardiac glycosides. A total of 30 substances has been traced by paper chromatography, of which only 8 (E, K, O, P, Q, R, S, and T) were present in amounts large enough to be traced without prior enrichment of the extracts. These substances could be isolated either in pure form or as enriched mixtures. Substances E, K, O, and S were obtained in crystalline form. Apart from these substances a large amount of a mixture (N) was obtained comprising 7 components. The substances E (mansonin) and O (strophallosid) could be identified with known cardenolides. The structure of O was known; the structures of E and K (strophothevosid) are reported in the following publication. The structures of the other isolated and enriched substances (P, Q, R, S, and T) were only partially elucidated.
Gymnemasäure, das antisaccharine Prinzip von Gymnema sylvestre R. Br. Isolierungen und Identifizierungen Glykoside und Aglykone 288. Mitteilung
Authors: Stöklin W. , Weiss E. , Reichstein T.
Published: December 2004

The isolation, characterisation, purity control and probable structure of gymnemic acid, the antisaccharine principle of Gymnema sylvestre R. Br. (Asclepiadaceae) has been reported. According to the results, gymnemic acid is the D‐glucuronide of a probably new hexahydroxy‐δ12‐oleanene which has been named gymnemagenin and which is esterified with various combinations of the following five acids: formic, acetic, n‐butyric, isovaleric, and tiglic acid. Gymnemic acid is not an absolutely pure substance. It is composed predominantly of gymnemic acid A1, which is accompanied by components having similar properties, especially the gymnemic acids A2, A3 and A4. The difference between these components probably lies in the absence or presence of one of the five named acids.
Präbetanin, ein Schwefelsäure‐halbester des Betanins. Ein Beitrag zur Kenntnis der Betacyane
Authors: Wyler H. , Rösler H. , Mercier M. , Dreiding André S.
Published: December 2004

Prebetanin, a minor companion of betanin in the red beet, was isolated and found to be the 6′‐sulfuric acid half‐ester of betanin. The arguments are based on elemental analyses, partial hydrolysis and methanolysis, and on comparison of the NMR‐spectra of prebetanin and betanin, and of their derivatives.
Thermische Umlagerungen der Caryophyllene
Authors: Ohloff G. , Uhde G. , Schulte‐Elte K. H.
Published: December 2004

(‐)‐Caryophyllen (1) lagert sich oberhalb 240° in (4S)‐(+)‐4,8,8‐Trimethyl‐4‐vinyl‐bicyclo[5.2.0]non‐2‐en (3) um, das sich über (‐)‐iso‐Caryophyllen (2) mit seinem Diastereomeren 4 ins Gleichgewicht setzt. Die Isomerisierungen erfolgen nach dem Prinzip einer Cope‐Umlagerung.
Über die Struktur der Phenazin‐N‐oxide
Authors: Siǵǵ H. P. , Toth A.
Published: December 2004

Für das Antibioticum Myxin wird die Struktur des 1‐Hydroxy‐6‐methoxy‐phenazin‐5,10‐dioxids (IV) bewiesen(2).
Un nouveau dispositif de micro‐analyse thermique
Authors: Duruz J. J. , Tissot P. , Monnier R.
Published: December 2004

A new device using electrically heated thermocouples for thermal micro‐analysis is described. Three examples of applications are given.
Die Reaktion von halogenierten s‐Triazinen mit Cyclopentadienylnatrium
Authors: Neuenschwander M. , Schaltegger H. , Stuber F.
Published: December 2004

Beim Umsatz von 2‐Chlor‐4,6‐dimethoxy‐s triazin mit Cyclopentadienylnatrium entstehen zwei isomere Dimere, für die auf Grund der NMR.‐Spektren die Strukturen 3(oder 4),8‐Bis‐(4,6‐dimethoxy‐2‐s‐triazinyl)‐tricyclo[5.2.1.02,6]deca‐3, 8‐dien (IIIa) und 1,3(oder 4)‐Bis‐(4,6‐dimethoxy‐2‐s‐triazinyl‐tricyclo[5.2.1.02,6]deca‐3, 8‐dien (IVa)) vorgeschlagen werden. Unter den gleichen Bedingungen erhält man aus 2,4‐Dichlor‐6‐methoxy‐s‐triazin und Cyclopentadienylnatrium neben einem höher‐molekularen Produkt in beträchtlichem Ausmass 3(oder 4), 8‐Bis‐(4‐chlor‐6‐methoxy‐2‐s‐triazinyl)‐tricyclo[5.2.1.02,6]deca‐3, 8‐dien (IIIb).
Über eine neue Synthese zur darstellung heterocyclisch substituierter Stilbenverbindungen, die Anil‐Sythese
Authors: Siegrist A. E.
Published: December 2004

Heterocyclische Ringsysteme aromatischen Charakters mit mindestens einem Ring‐Stickstoffatom, die eine oder mehrere p‐Tolylgruppen oder in einem an den Heterocyclus ankondensierten Benzolring eine Methylgruppe in p‐Stellung zu einer CN‐oder NC‐Gruppe des Heterocyclus enthalten, können in Dimethylformamid in Gegenwart von Kaliumhydroxid oder Kalium‐t‐butylat mit aromatischen Aldehydanilen zu heterocyclisch substituierten Stilbenverbindungen umgesetzt werden.
La configuration du «carquéjol» (Isopropényl‐2‐méthylène‐3‐cyclohexène‐4‐ol) et la conformation privilégiée de l' ortho‐néo‐isomenthol
Authors: Thomas Alan F.
Published: December 2004

The complete stereochemistry of carquejol (= cis‐(2S)‐isopropenyl‐3‐methylene‐cyclohex‐4‐en‐1‐ol) is described. The absolute configuration was obtained from the circular dichroism of the corresponding 0‐menthones. Carquejol and its reduction products, having the all‐cis configuration, appear from NMR. measurements to prefer a conformation having the hydroxyl (or acetoxyl) group axial and the isopropenyl (or isopropyl) group equatorial, even when the exo‐methylene group is reduced to methyl. The mass spectra of the compounds are briefly described.
Steroide und Sexualhormone 232. Mitteilung [1] die synthese von 1β, 4β‐oxido‐3‐aza‐17β‐hydroxy‐a‐homo‐5α‐androstan vorläufige mitteilung
Authors: Eggart Fr L. G. , Pascual C. , Wehrli H.
Published: December 2004

A sterically controlled transformation of 3‐oxo‐17β‐acetoxy‐Δ1−‐α‐androstene (2) into 1β,4β‐oxido‐3‐aza‐17β‐hydroxy‐A‐homo‐5α‐androstane (16) is described. With the exception of two conversions [14→15 (60%); 15 →16 (50%)], the yields of the remaining seven steps are higher than 75% each. The reaction sequence will serve as a model for an analogous partial synthesis of samandarine (1).
Stereochemie und Konformation des Swerosids
Authors: Linde Horst H. A. , Ragab Mohamed S.
Published: December 2004

Stereochemie und Konformation des Swerosids und seiner Abkömmlinge werden abgeklärt.
Catalyse acide de certaines réactions nucléophiliques en série phosphoranique. ‐ Action de l'anhydride chloracétique sur les alcoxycarbonylméthylène‐phosphoranes
Authors: Chopard P. A.
Published: December 2004

(Alkoxycarbonyl‐chloroacetyl‐methylene)‐phosphoranes dealkylate in the presence of acids and give the very stable lactone‐betaine IV. The mechanism of this reaction is tentatively compared to other known dealkylations catalysed by protons or quaternary phosphonium compounds.
Die Kristall‐ und Molekelstruktur des Naphtalin‐chromtricarbonyl C10H8Cr(CO)3
Authors: Kunz V. , Nowacki W.
Published: December 2004

Naphtalin‐chromtricarbonyl kristallisiert in 2 Modifikationen: (a) als Schindeln mit a=12,37, b=6,58, c=7,36 Å, α=107°22′, β=96°44′, γ=92°50′, P1 oder P\documentclass{article}\pagestyle{empty}\begin{document}$ \mathop 1\limits^ - $\end{document}, Z=2, und (b) als Nadeln mit a=13,98, b=11,71, c=6,87 α, P212121, Z=4. Von letzterer wurde mittels einer 3d‐Patterson‐Synthese, gefolgt von mehreren 3d‐Fourier‐und ‐Differenz‐Fourier‐Synthesen und Kleinste‐Quadrate‐Verfeinerungen die vollständige Struktur bestimmt (R=8,5%). Die C‐C‐Abstände im ebenen Naphtalinring von 1,375‐1,447 α weisen gegenüber denjenigen im Naphtalin selber (1,364‐1,427 Å) keine wesentliche, durch den Cr(CO)3‐Komplex bedingte Auflockerung auf. Keine Carbonylgruppe liegt in der «langen» Spiegelebene der Naphtalinmolekel, sondern jede ist aus ihr herausgedreht. Die zwischenmolekularen Abstände von 3,34‐3,71 Å fallen in den Bereich schwacher (CH…O)‐Wechselwirkungen.
N‐Terminale Sequenzanalyse von Peptiden mittels EDMAN‐Abbaus: Kombinierte Anwendung der direkten und der subtraktiven methode
Authors: Pataki György
Published: December 2004

A particularly reliable N‐terminal sequence analysis of peptides can be achieved by the following combined application of Edman's phenylisothiocyanate technique, and thin‐layer chromatography. The N‐terminal amino acids acids split off are identified as phenylthiohydantoin‐ and dimethylaminonaphthalensulfonyl‐derivatives; additionally, quantitative analysis of amino acids using thin‐layer chromatography is carried out before and after each degradation step. The applicability of this combined procedure is demonstrated in the case of a nonapeptide.
Etudes sur les composés organométalliques I action du chlorure de benzylmagnésium et du bromure de phénylmagnésium sur le tétrachlorure de titane
Authors: Boustany Kamel S. , Bernauer Klaus , Jacot‐Guillarmod André
Published: December 2004

The reactions between phenylmagnesium bromide or benzylmagnesium chloride and titanium tetrachloride have been studied. The influence of the introduction order of the reagents is mentioned. Decomposition of the (non‐isolated) compounds RnTiX4‐n is shown to be essentially intermolecular, and rarely intramolecular.
Etudes sur les composés organométalliques II [1] Etude spectrophotométrique IR. de quelques complexes de TiCl4 avec la pyridine et des pyridines substituées
Authors: Boustany Kamel S. , Bernauer Klaus , Jacot‐Guillarmod André
Published: December 2004

The preparation of some complexes of titanium tetrachloride with pyridine and substituted pyridines is described. The IR. spectra of the complexes compared with those of the pure ligands (L) indicate the presence of L→Ti dative bonds in the complexes.
Über die Chemie des Vitamins E 7. Mitteilung [1] die stereospezifische Cyclisierung von (3′R, 7′R, 11′R)‐α‐Tocopherolchinon
Authors: Mayer H. , Vetter W. , Metzger J. , Rüegg R. , Isler O.
Published: December 2004

Stereospecific cyclizations of (3′R, 7′R, 11′R)‐α‐tocopherolquinone (2) are reported:

Treatment with conc. sulfuric acid in methanol at 0‐5° gave (2R, 4′R, 8′R)‐α‐tocopherol (1a) with complete retention of configuration at C‐3′.
Zur Taktizität anionisch hergestellter Poly‐α‐methylstyrole
Authors: Lüssi H. , Barman J.
Published: December 2004

α‐Methylstyrene has been polymerized with lithium, sodium and potassium naphthalene in tetrahydropyran, tetrahydrofuran and 1.2‐dimethoxyethane at −30°. The tacticity of the polymers was determined by NMR. spectroscopy. Within the limits of reliability no influence of the cation on the tacticity was observed. With growing polarity of the solvent a slight but definite trend towards higher stereospecifity was noticed. The distribution of isotactic and syndiotactic links is purely statistical. The considerable dependence of tacticity upon the polymerization mechanism is ascribed to differences in the steric configuration of carbanions and carbonium ions due to different hybridization.
«α»‐, «β»‐ und «δ»‐Anhydrodigitoxigenin. Glykoside und Aglykone, 293. Mitteilung
Authors: Janiak P. St. , Weiss Ek. , Rechstein T.
Published: December 2004

The syntheses of 3β‐hydroxy‐5β‐carda‐14, 20:22‐dienolide (= «β»‐anhydro‐), 3β‐hydroxy‐5β‐carda‐8:14, 20:22‐dienolide (= «α»‐anhydro‐) and «δ»‐anhydro‐digitoxigenin (= probably 3β‐hydroxy‐5β, 14β‐carda‐8, 20:22‐dienolide) by the best ways known to date, have been described. «δ»‐Anhydro‐digitoxigenin represents the thermodynamically most stable isomer. In this isomer the double bond in position 8 is unaffected by hydrogenation with Pt in acetic acid; with perbenzoic acid an epoxide results from which, on hydrogenation, the double bond can be regenerated in its original position. Analogous reactions are known to occur in the 8:14‐epoxides.
Über Muscarin. 15. Mitteilung [1]. Reduktion von Normuscaron mit Borwasserstoff und bicyclische Derivate der Muscarinreihe
Authors: Hardegger E. , Halder N.
Published: December 2004

Die Reduktion von Normuscaron (IIb) mit Borwasserstoff führte wie die meisten andern bisher untersuchten Reduktionsmethoden zu allen 4 Norbasen (III, IIIa, IIIb, IIIc) der Muscarinreihe, für deren chromatographisch‐analytische Bestimmung ein einfaches, zuverlässiges System gefunden wurde. Zwei stereoisomere Verbindungen mit der Struktur des N‐Benzylderivats II wurden nebst dem N, N‐Bisnormuscaron (IIa) erstmals hergestellt.
Nichtstationäre Kinetik bei SN1, SN2, E1, E2 und E1cb‐Mechanismen
Authors: Frei K. , Günthard Hs. H.
Published: December 2004

For the SN1, SN2, E1, E2, AND E1cb mechanisms exact solutions of the kinetic equations are compared with solutions obtained under the hypothesis of stationarity. Exact integrals are calculated numerically for a set of the essential reaction rate constants. Comparison with the stationary state solution demonstrates that both types of solutions are approximately equal in many cases if the transient particle concentration remains low, whereas the conventional requirement | \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop x\limits^. $\end{document} | = 0 is unimportant. For approximation of exact kinetics by stationary kinetics, however, neither condition is sufficient nor necessary. Practical criterions for recognition of deviations from stationary kinetics are given.
Etude sur les composés organométalliques III [1]. Action d'organomagnésiens sur des complexes du tétrachlorure de titane
Authors: Boustany Kamel S. , Bernauer Klaus , Jacot‐Guillarmod André
Published: December 2004

The reaction between RMgX and TiCl4,2L (L = pyridine, piperidine or quinoleine) is shown to give a high yield of organo‐titanium (IV) compounds. As expected, the decomposition of the latter is reduced to a minimum by the ligand L initially present, allowing the preparation of etheral solutions of R4Ti (R = benzyl, phenyl or butyl). R4Ti is obtained whatever may be the initial molar ratio of RMgX/TiCl4, 2L.
Über Inhaltsstoffe des Haschisch. 2., vorläufige Mitteilung. Synthese von (−)‐Δ6, 1‐3, 4‐trans‐Tetrahydrocannabinol, sowie von (±)‐Δ6, 1‐3, 4‐trans‐Tetrahydrocannabinol
Authors: Petrzilka T. , Sikemeier C.
Published: December 2004

Acids, such as p‐toluenesulfonic acid, mediate the direct formation of optically active (−)‐Δ6,1‐3,4‐trans‐tetrahydrocannabinol from (+)‐cis‐or (+)‐trans‐p‐menthadiene‐(2,8)‐ol‐(1) and olivetol.
Sur la composition de l'arôme de cacao
Authors: Marion J. P. , Müggler‐Chavan F. , Viani R. , Bricout J. , Reymond D. , Egli R. H.
Published: December 2004

A gas‐chromatographic separation of cocoa aroma, followed by infra‐red and mass‐spectrometric identification, has yielded, besides 22 of the 91 previously described constituents, 35 new substances (8 aliphatic, 1 alicyclic, 7 aromatic, 9 o‐heterocyclic, 4 pyrrolic, and 6 pyrazinic).
Stoffwechselprodukte von Mikroorganismen. 57. Mitteilung. Boromycin
Authors: Hütter R. , Keller‐Schien W. , Knüsel F. , Prelog V. , Rodgers G. C. , Suter P. , Vogel G. , Voser W. , Zähner H.
Published: December 2004

A new strain of Streptomyces antibioticus (WAKSMAN et WOODRUFF), ETH 28829, produces a novel antibiotic, boromycin, which appears to be the first well defined boron containing organic compound to have been found in nature. Boromycin is a complex of boric acid with a tetradentate organic complexing agent, that yields by hydrolysis D‐valine, boric acid, and a polyhydroxy compound of macrolide type.
Podophyllum‐ Lignane: Struktur und Absolutkonfiguration von Podorhizol‐β‐D‐glucosid ( = Lignan F). 19. Mitt. über mitosehemmende Naturstoffe [1]
Authors: Kuhn M. , Von Wartbung A.
Published: December 2004

Podorhizol‐β‐D‐glucoside (1) ( = lignan F), C28H34O13, a new lignan from the roots and rhizomes of Podophyllum species, represents one of the rare glucosides which are cleaved by acids as well as by bases. Acid hydrolysis furnished the intact aglycone podorhizol (3) and in addition two cyclisation products characterized as desoxy‐podophyllotoxin (10) and (−)‐isodesoxypodophyllotoxin (11), respectively. Base catalysed fission of the glucoside 1 yielded D‐glucose and anhydropodorhizol (9). Podorhizol was smoothly oxidized to the corresponding ketone podorhizone (5), which upon treatment with NaOCH3 underwent cleavage into methyl 3,4,5‐trimethoxy‐benzoate (8) and the benzylbutyrolactone derivative 7. These findings combined with spectroscopical evidence revealed the structure of podorhizol as a 2,3‐dibenzylbutyrolactone derivative.
Synthesen in der Carotinoid‐Reihe. 22. Mitteilung. Totalsynthese von Rhodoxanthin
Authors: Mayer H. , Montavon M. , Rüegg R. , Isler O.
Published: December 2004

The total synthesis of rhodoxanthin according to the scheme C14 + C12 + C14 is reported.
Développement électrolytique et photolyse de plaques minces d'halogénures d'argent
Authors: Fernández‐Garcia J. G. , Guillemin M. , Boissonnas Ch. G.
Published: December 2004

The silver grains, formed by the reduction of a monocrystalline surface of silver chloride (obtained by capillary ascension of molten chloride between two plates of glass), with an hydroquinone developer containing 1–2% of gelatine are orientated only in [001] planes.
Über Pterinchemie. 21., vorläufige Mitteilung [1]. Hydroxylierung der Tryptophans mittels Tetrahydropterin unter physiologischen Bedingungen
Authors: Viscontini M. , Mattern G.
Published: December 2004

Tryptophan wird an der Luft in wässeriger Lösung mittels Tetrahydropterin, Eisen(II) und Pyrophosphat unter physiologischen Bedingungen hydroxyliert, wobei das Substrat an verschiedenen Stellen angegriffen wird. Isoliert wurden 5‐Hydroxytryptophan, Melanin, Kynurenin, 3‐Hydroxykynurenin, Xanthommatin, ferner einfache Indolderivate und α‐Aminosäuren. Die Gesamtausbeute an Umwandlungsprodukten, die in 1½ Stunden unter milden Bedingungen erhalten wurden, entspricht 2–3% des eingesetzten Tryptophans.
Recherches sur la biochimie des cyclitols X. Sur les cyclitol‐déshydrogénases d'Acetobacter suboxydans I
Authors: Rapin A. , Haenni A. L. , Posternak Th.
Published: December 2004

(1) On a étudié deux souches d'Acetobacter suboxydans désignées comme HL I et HL II, qui oxydent en monocétones les cyclohexanediols‐1,2 cis et trans et le cyclohexanetriol‐1,2,3/0(cyclitols inférieurs). Contrairement à la souche d'A.sub. KLUYVER de LEEUW, elles ne s'attaquent pas aux cyclitols supérieurs contenant au moins 4 OH voisins.
Recherches dans la série des cyclitols XXXVI. Oxydations biochimiques de cyclohexane‐tétrols et ‐triols et d'un méthoxy‐cyclohexanediol
Authors: Barbezat P. , Reymond D. , Posternak Th.
Published: December 2004

L'oxydation par Acetobacter suboxydans KLUYVER‐DE LEEUW des (±)‐cyclohexanetétrols‐1,2,4/3 et ‐1,2,3/4 et du (±)‐cyclohexanetriol‐1,2/3 comporte une attaque de l'hydroxyle axial de chacun des antipodes des trois substrats. Cette oxydation est due aux déshydrogénases particulaires qui s'attaquent aux cyclitols supérieurs. Sous l'action d'une épimérase contenue dans les bactéries, les cétoses dérivés du (+)‐cyclohexanetétrol‐1,3,4/2 et des (+)‐ et (−)‐cyclohexanetétrols‐1,2,3/4 sont convertis en cétoses épimères.
Ternäre Komplexe in Lösung II. Einfluss von 2,2′‐Bipyridyl auf die Stabilität des Cu2+‐Glycin‐1:1‐Komplexes
Authors: Sigel Helmut , Griesser Rolf
Published: December 2004

The stability constant of the Cu2+‐2,2′‐bipyridyl‐glycine complex (log K = 7,88) was measured and compared with that of the binary Cu2+‐glycine complex (log K = 8,27). The value Δ log K = −0,4 (cf. equation (3)) is in the order which should be expected for the coordination of a mixed ON‐ligand to (Cu‐Bipy)2+ which results in the formation of a ternary complex (cf. [1]).
De la chimie des ptérines. 22e communication [1]. Sur le mécanisme d'oxydation des tétrahydroptérines et plus particulièrement de la méthyl‐5‐diphényl‐6,7‐tétrahydro‐5,6,7,8‐ptérine
Authors: Viscontini M. , Okada T.
Published: December 2004

On décrit comment la méthyl‐5‐diphényl‐6,7‐tétrahydro‐5,6,7,8‐ptérine s'autoxyde en milieu alcalin en utilisant un atome‐équivalent d'oxygène pour former l'hydroxy‐4a‐méthyl‐5‐tétrahydroptérine quinolique correspondante. L'oxydation est catalysée par Fe3+, qui forme d'abord un complexe avec la tétrahydroptérine. Dans ce complexe un électron est transféré de la tétrahydroptérine sur le fer. Un mécanisme radicalaire d'oxydation des tétrahydroptérines, basé sur ces données expérimentales, est proposé et discuté.
Gas‐chromatographische und massenspektrometrische Untersuchung von Phytylubichinon, Vitamin K1 und Vitamin K2
Authors: Vetter W. , Vecchi M. , Gutmann H. , Rüegg R. , Walther W. , Meyer P.
Published: December 2004

The trimethylsilyl ethers of reduced vitamins K1, K2, and of phytylubiquinone were investigated by means of gas chromatography and mass spectrometry.
Die Glykoside der Blätter von Isoplexis canariensis (L.) G. DON. 2. Mitteilung
Authors: Spengel Sigrid , Hauser Emil , Linde Horst H. A. , Vaz Anthony X. , Meyer Kuno
Published: December 2004

Aus den getrockneten Blättern von Isoplexis canariensis liess sich nach leichter Abänderung des früher [2] beschriebenen Verfahrens in etwa 1% Ausbeute ein Kristallisat gewinnen, das aus den zwei Glykosidgemischen «A» und «B» im ungefähren Verhältnis 1:4 besteht. Diese unterscheiden sich nur im Zuckerteil ‐ Canarobiose beim Glykosid «A» und Digilanidobiose beim Glykosid «B» ‐ und besitzen die gleichen Aglykone: Uzarigenin, Canarigenin und Xysmalogenin. −2 der 3 Komponenten des Glykosids «A», nämlich Uzarigenin‐glucosido‐canarosid und Canarigenin‐glucosido‐canarosid, konnten als einheitliche Kristallisate gewonnen und in die Desglucoprodukte übergeführt werden. Das der 3. Komponente des Glykosids «A» entsprechende Desglucoprodukt, das Xysmalogenin‐canarosid, liess sich aus dem Monosidgemisch «e» [2] (das aus «A» durch enzymatische Hydrolyse entsteht) gewinnen. ‐Das Glykosid «B» konnte bisher noch nicht in seine 3 Komponenten aufgeteilt werden. Aus seinem Monosidgemisch «d» wurden Uzarigenin‐digitoxosid sowie Canarigenin‐digitoxosid als einheitliche Glykoside und, nach saurer Hydrolyse, Xysmalogenin, das Aglykon des dritten Digitoxosids von «d», gewonnen. ‐ Aus den Mutterlaugen der Glykosidgemische «A» und «B» konnten noch die Substanzen C und «D» erhalten werden. C ist Canarigenin‐glucosido‐fucosid, während «D» ein Gemisch mehrerer Glykoside darstellt.
Über Inhaltstoffe von Achillea santolinaL. (Compositae). 1. Mitt.: Die Stereochemie von Desacetoxy‐matricarin
Authors: Linde Horst H. A. , Ragab Mohamed S.
Published: December 2004

Die Stereochemie des Santolins = Desacetoxy‐matricarins = Leukodins wird abgeklärt.
Recherches sur la formation et la transformation des esters LXXVI [1] Sur la réaction de l'isocyanate d'o‐méthoxycarbonyl‐phényle avec quelques acides amino (ou hydrazino) alcoyl‐orthophosphoriques et ‐sulfuriques
Authors: Cherbuliez Emile , Espejo O. , Jindra H. , Rabinowitz J.
Published: December 2004

o‐Methoxycarbonyl‐phenyl isocyanate reacts with mono‐aminoalkyl orthophosphoric and sulfuric acids to yield the corresponding 1,2,3,4‐tetrahydroquinazoline‐2,4‐dione‐3‐ethyl phosphoric (or sulfuric) monoesters which are isolated as sodium salts. 1,2,3,4‐Tetrahydroquinazoline‐2,4‐dione‐3‐ethyl phosphoric acid has been isolated by adding hydrochloric acid to an aquous solution of its sodium salt.
Zur Struktur von H3Co(CN)6 und Ag3Co(CN)6
Authors: Ludi A. , Güdel H. U. , Dvořák V.
Published: December 2004

The X‐ray powder patterns of H3Co(CN)6 and Ag3Co(CN)6 have been indexed on the basis of a hexagonal unit cell:

equation image

The length of the NXN‐bond along the c‐axis is 3.29 Å for X  H and 4.24 Å for X  Ag. These distances are in agreement with data obtained from infrared spectra and with structural properties of similar compounds.
Chronoamperometrische Untersuchung der Thalliumabscheidung aus methanolischer Lösung an einer Silberelektrode vom Kammertyp
Authors: Schmidt E. , Wüthrich N.
Published: December 2004

Unter Anwendung einer chronoamperometrischen Dünnschichtmethode wurde die Abscheidung von Thallium auf Silberelektroden aus methanolischen Perchloratlösungen auf Kationenmonoschichtbildung hin untersucht. Die erhaltenen Stromspannungskurven unterscheiden sich nur wenig von den Chronoamperogrammen entsprechender wässeriger Lösungen, woraus geschlossen wird, dass die innerste Region der starren Doppelschicht der Silberelektrode in Gegenwart des Thalliumadsorbats in Wasser und Methanol im wesentlichen die gleichen Eigenschaften besitzt.
Sur la réaction fluorescente de l'acide borique avec l'hydroxy‐2‐methoxy‐4‐chloro‐4′‐benzophénone (HMCB) en milieu sulfurique‐acétique concentré et sur le rôle de certaines propriétés du milieu
Authors: Marcantonatos M. , Monnier D.
Published: December 2004

By analogy with some colour reactions of boric acid, the intensity of fluorescence emission of the “boric acid‐2‐hydroxy‐4‐methoxy‐4′‐chloro‐benzophenone” complex is found to be considerably increased in glacial acetic‐concentrated sulfuric acid medium. This effect is studied with relation to some properties of the medium, especially acidity and viscosity.
Lineare Korrelation der chemischen Verschiebung der Vinylprotonen mit den LCAO‐MO‐π‐Elektronendichten in meta‐ und para‐substituierten Styrolen und Zimtsäuren
Authors: Wehrli F. W. , Pretsch E. , Simon W.
Published: December 2004

A linear correlation was found between the proton chemical shifts of the vinyl protons in m/p‐substituted styrenes and cinnamic acids and the π‐electron densities of the corresponding carbon atom, calculated by the simple LCAO‐MO procedure, using standard values for the perturbation parameters.
Reduktive Photoalkylierung des Flavinkerns und Flavinkatalysierte Photodecarboxylierung von Phenylacetat Studien in der Flavinreihe. 15. Mitteilung [1]
Authors: Walker W. H. , Hemmerich P. , Massey V.
Published: December 2004

Structure and properties of leucoflavin derivatives obtained through flavinsensitized photodecarboxylation of phenylacetate ions are described. The photoreduction of flavin with phenylacetate as donor is shown to be a quantitative photoalkylation, the benzyl residue entering either position 5 (nitrogen) or the bridge position 4a (carbon) of the flavin nucleus, depending on the conditions. The isomers were isolated, and identified by IR., NMR., and elementary analysis. The benzyl residue migrates from N(5) to C(4a) upon heating.
Die Glykoside der Wurzeln von Asclepias swynnertonii S. Moore. Glykoside und Aglykone,303. Mitteilung
Authors: Jäggi Kurt , Kaufmann H. , Stöcklin W. , Reichstein T.
Published: December 2004

The roots of Asclepias swynnertonii S. Moore are very rich in glycosides, the major portion being pregnane glycosides besides small amounts of cardenolides. Six cardenolides could be identified by means of chromatography: coroglaucigenin, ascleposide, uzarigenin, uzarin, corotoxigenin and frugoside, of which the first two mentioned substances could be preparatively isolated.
Dünnschichtchromatographie als Hilfsmittel in der Radiochemie. 2. Mitteilung [1]. Untersuchung von Produkten der Neutronenbestrahlung einiger anorganischer Salze
Authors: Seiler H. , Seiler M.
Published: December 2004

The chemical fate of sodium pyrophosphate and sodium salts of chloro‐acids in neutron irradiation, and the influence of the presence of metal‐ions was investigated by using thinlayer chromatography for separations of reaction products, and radiometric measurements.
Fragmentierung von α‐Aminoketoximen. IV. Teil Der Einfluss sterischer. Faktoren Fragmentierungsreaktion, 17. Mitteilung
Authors: Grob C. A. , Sieber A.
Published: December 2004

(N‐Methyl‐2‐piperidyl)phenyl ketoxime acetate(10b) and (N‐methyl‐2‐pyrrolidinyl)‐phenyl ketoxime acetate (13b) undergo quantitative fragmentation in 80% ethanol to yield benzonitrile and the cyclic imonium salts 11 and 14. Their reaction rates are approx. 107 and 108, respectively, as high as those calculated for the homomorphous compounds, viz. 2‐methylcyclohexylphenyl ketoxime acetate (12b) and 2‐methylcyclopentylphenyl ketoxime acetate (15b), which undergo quantitative Beckmann rearrangement. Synchronous fragmentation therefore provides a very large driving force for ionisation, even when the stereo‐electronically suitable conformation is not the prevalent one, as with 10b.
Fragmentierung von α‐Aminoketoximen. V. Teil. (2‐Chinuclidinyl)‐phenyl‐ketoxim. Zur Gültigkeit der BREDTschen Regel bei energiereichen Zwischenstufen Fragmentierungsreaktionen, 18. Mitteilung
Authors: Grob C. A. , Sieber A.
Published: December 2004

The reaction of (2‐quinuclidinyl) phenyl ketoxime tosylate (1) in aqueous ethanol or tetrahydrofuran yields 10 to 20% of benzonitrile and 4‐piperidyl‐acetaldehyde (6), the tautomer of 2‐quinuclidinol (5), besides N‐(2‐quinuclidinyl)‐benzamide (4). In phenol some 2‐phenoxyquinuclidin (21) and benzonitrile are obtained besides phenyl N‐(2‐quinuclidinyl)‐benzimidate (20). Furthermore, the α‐aminoketoximetosylate 1 reacts 2 to 4 times as fast as the homomorphous (bicyclo[2.2.2]‐2‐octyl) phenyl ketoxime tosylate (7). By contrast the latter untergoes quantitative Beckmann rearrangement to the amide 12.
Sur les relations entre structure polypeptidique et activité Strépogénique. 1. Peptides de la cystine
Authors: Baudet P. , Borecka I. , Cherbuliez E.
Published: December 2004

The authors propose for the characterization of strepogenic substances of known composition the specific activity, i. e. the number of WOOLLEY units per μmole.

Starting from L‐leucyl‐L‐cystinyl‐L‐leucyl‐L‐valyl‐L‐glutamic acid (of very high strepogenine activity, 400 WOOLLEY units per mg, 230 WOOLLEY units per μmole) seven peptides have been synthesized by suppression and/or replacement of amino acid residues. A study of the relation between activity and structure of these peptides shows that:

In this group cystine is an indispensable element for activity.

This amino acid must either be linked on each side to leucine residues or linked by its carboxyles to leucine, its amino groups being free.

From these results, the conception emerges that the strepogenine polypeptides may be characterized by an amino acid (in this group of peptides, cystine) which must be linked to particular amino acid residues. If this conception is correct, there should exist several types of strepogenines depending on the nature of the amino acid essential for their activity.
Zur informationstheoretischen Deutung der thermodynamischen Mischungsfunktionen einiger einfacher Gittermodelle
Authors: Milićević B.
Published: December 2004

The thermodynamic functions of mixing for some simple lattice models (perfect, athermal, and simple mixtures) have been derived by means of SHANNON'S uncertainty measure and the fundamental ideas of JAYNES' information‐theoretical formalism.
Elektromotorische Eigenschaften eines Gallium‐Silicium‐Kalium‐Glases zur Messung von Kaliumionen‐Aktivitäten
Authors: Štefanac Z. , Simon W.
Published: December 2004

A gallium glass for the measurement of potassium ion activity is described. The corresponding glass electrodes show a selectivity for potassium over sodium of about 10.
Methode zur Konstitutionsaufklärung der Reaktionsprodukte der Umsetzung von Cellulose mit Formaldehyd. 18. Mitteilung über textilchemische Untersuchungen [1]
Authors: Patel S. , Rivlin Joseph , Samuelson T. , Stamm O. A. , Zollinger H.
Published: December 2004

(1) A method is described which allows the elucidation of the structure of cotton cross‐linked with formaldehyde. It consists of a permethylation process (5 methylations with dimethyl sulphate and sodium hydroxide in dimethyl sulphoxide, followed by two exchange methylations of the formalised sodium cellulosate with methyl iodide in n‐butanol), hydrolysis of the product in 72% sulphuric acid to the respective methylated glucoses, reduction of the mixture of glucoses to the respective sorbitols, blocking of all free hydroxyl groups by acetylation, trifluoroacetylation or formation of trimethylsilyl ethers, and vapour phase chromatographic separation of the derivatives.

(2) It is shown that after permethylation practically no free hydroxyl groups can be detected and that scarcely any replacement of methylene or oxymethylene cross‐links by methyl groups has taken place. With the exception of losses in filtration of the permethylation product, all stages of the process proceed on an almost quantitative basis.
Lösungsmitteleffekte in Kernresonanzspektren gesättigter Kohlenwasserstoffe
Authors: Winkler T. , Von Philipsborn W.
Published: December 2004

Proton NMR solvent effects ν(CCl4) – ν(C6H6) have been measured for the methyl groups in 25 saturated cycloalkanes. Magnitude and sign of the Δ values are correlated with the molecular shape. The results are discussed with particular respect to stereochemistry, and they provide a new method for distinguishing between geometrical isomers.
Die Electronenzustände von Perimeter‐π‐Systemen: III. Das Elektronenspektrum des 1,6‐Methano‐[11] annulenium‐Kations
Authors: Grimme W. , Heilbronner E. , Hohlneicher G. , Vogel E. , Weber J. P.
Published: December 2004

The electronic spectra and the polarisation of the transitions have been determined for the 1,6‐methano‐[11] annulenium cation III and the 4,6‐dimethyl‐1,2‐benzotropylium cation IV. The observed sequence of polarisation of the prominent bands corresponding to the lowest electronically excited states is in agreement with the predictions derived from molecular orbital models of the PARISER‐PARR‐POPLE type. The influence of partial conjugation between the bridged centre and of the inductive effect of the methylene group in III has been investigated.
Synthese von 2‐ und 3‐(1,2,3,6‐Tetrahydropyridyl)‐indolen
Authors: Beck D. , Schenker K.
Published: December 2004

The synthesis of a series of 2‐ and 3‐(1,2,3,6‐tetrahydro‐4‐pyridyl)‐indoles by reduction of the corresponding pyridinium compounds with sodium borohydride is described. A substantially improved mode of preparation for 3‐(4‐pyridyl)‐indole is given.
Reaktionen von Steroid‐Hypojoditen IX. Beitrag zum Mechanismus der oxydativen Cyanhydrin‐Cyanketon‐Umlagerung Über Steroide, 212. Mitteilung
Authors: Kalvoda J.
Published: December 2004

The intramolecular character of the oxidative cyanohydrin‐cyanoketone rearrangement has been proven by cross experiments using 14C‐labeled compounds. The shown stereochemical requirements of the reaction and its analogy to the hypoiodite oxidation [3] of monohydric alcohols lead to the formulation of a reaction mechanism involving an internal addition of a carbon radical centre to the triple bond of a cyano group.
Organische Phosphorverbindungen XXXI. Ein einfaches Verfahren zur Herstellung von Alkylen‐ bzw. Arylen‐ bzw. diphosphiniten und von Bis‐(dialkyl‐ und diaryl‐phosphinyl)‐alkanen
Authors: Maier Ludwig
Published: December 2004

The reactions of dialkylamino‐dialkyl‐ or diaryl‐phosphines, R2PNR′2 (R = C6H5 C4H9, C2H5; R′ = CH3, C2H5) with unsaturated alcohols, functional alcohols, α, ω‐alkane‐diols and α, ω‐alkane‐dithiols have been studied. The preparation of a large number of alkylene (or arylene) bis‐phosphinites and of bis‐phosphinyl‐alkanes is reported and their physical properties listed.
Die Kinetik der thermischen Cyclisierung von 2,6‐Dimethyl‐1, cis‐3,5‐heptatrien in der Gasphase
Authors: Egger Kurt W.
Published: December 2004

The kinetics of the thermal cyclization of 2,6‐dimethyl‐1, cis‐3, 5‐heptatriene to 1, 5, 5‐trimethyl‐1, 3‐cyclohexadiene have been measured in the gas phase for temperatures ranging between 150.4 and 231.2°C. The observed reaction rates satisfy first order kinetics for pressures ranging between 2.5 and 25 torr. The reaction is homogeneous, as demonstrated by the insensitivity of the calculated rate constants towards a 13‐fold variation in the surface to volume ratio of the reaction vessels used. The least squares regression analysis of the observed rate constants yields (with standard errors) log kcycl. (s−1) = (10.50 ± 0.11) − (31.81 ± 0,24)/θ, where θ equals 4.58 × 10−3 T (°K).

The trans isomer is stable under the reaction conditions used. The intramolecular reaction proceeds via a 6‐center cyclic transition state, involving a loss in entropy of ∼ 13.8 cal/°‐mole (based on the transition state formulation for unimolecular reactions, assuming a transmission coefficient of unity). When compared with estimated and with reported activation parameters for the cyclization of 1, cis‐3,5‐hexatriene, this amounts to an additional loss of ∼ 4.5 e.u., and an increase in Ea by ∼ 2 kcal/mole. This is attributed to the additional steric repulsions in the transition state, primarily owing to the methyl group in 6‐position.
Intramolekulare [2π + 2σ]‐Thermo‐cycloadditionen Synthese von Bis‐homo‐cyclopentadien‐Derivaten Vorläufige Mitteilung
Authors: Prinzbach H. , Martin H.‐D.
Published: December 2004

Intramolecular thermal [2π + 2σ]‐cycloaddition reactions in the tricyclo[3.2.1.02,4]‐oct‐6‐ene system are described. Within a certain set of conditions no [2π + 2σ]‐additions within some tricyclo[5.1.0.03,5]octane derivatives could be achieved.
Die Strukturen der mittleren Ringverbindungen XV. 6‐Ketononanolid (Oxacyclodeca‐2,7‐dion)
Authors: Fedeli Walter , Dunitz J. D.
Published: December 2004

Crystals of 6‐ketononanolide (oxacyclodeca‐2,6‐dione) are orthorhombic, a = 8.886, b = 16.407, c = 11.965 Å, space group Pbca, with 8 molecules in the unit cell. The structure has been solved with the help of direct methods and refined by full‐matrix least‐squares analysis of three‐dimensional intensity data. The conformation of the ring is similar to that previously observed in several cyclodecane derivatives, with the ring oxygen and carbonyl groups so situated as to minimize the number of transannular H … H contacts. Evidence for transannular O(ether) … C(carbonyl) donor‐acceptor attraction is discussed.
Synthèse des (±)‐loliolide, (±)‐actinidiolide, (±)‐dihydroactinidiolide et dérivés à partir d'acide homosafranique. Photooxygénation sensibilisée de I'homosafranate de méthyle
Authors: Demole Edouard , Enggist Paul
Published: December 2004

We have synthesized (±)‐loliolide (7 a), (±)‐actinidiolide (11 a), (±)‐dihydroactinidiolide (16), and (±)‐isodihydroactinidiolide (18) through various reaction paths starting from homosafranic acid (4 a). Thus, (±)‐actinidiolide has been synthesized for the first time, and this result allows to discard the alternative formula 11 b for that compound [2].

By investigation of the sensitized photooxygenation of methyl homosafranate (4 b), this reaction is shown to lead to an interesting spiro‐peroxylactone 25, beside the expected endo‐peroxide 23. Specific oxygenation of the tetrasubstituted double bond of methyl homosafranate, and cyclisation of the hydroperoxide 24 thus produced, are believed to account for the formation of such a particular compound.

The base‐catalysed rearrangement of the endo‐peroxide 23 gives rise to two compounds, one being the expected keto‐hydroxy‐ester 26. The other ‐ to which is assigned the glycidic ester structure 27 ‐ obviously results from an internal displacement reaction on oxygen in 23. It is note‐worthy that the sensitized photooxygenation of methyl homosafranate proceeds directly to the same glycidic ester when it is carried out in an alcaline solution.
Die Kristallstruktur eines 1:2‐Chrom(III)‐Komplexes vom Sandwichtypus
Authors: Joggi J.
Published: December 2004

The crystal structure of the triclinic modification of the 1:2 complex of chromium‐(III) with the azo dye from 3‐methyl‐anthranilic acid with 1‐(4‐bromophenyl)‐3‐methyl‐5‐pyrazolone has been determined. The space group is P1 with a = 13,46 Å, b = 14,79 Å, c = 12,56 Å, α = 62°30′, β = 106°51′ and γ = 98°25′. The structure was solved by the heavy atom technique and refined by blockdiagonal least squares method. The sandwich configuration postulated by SCHETTY [1] was confirmed.
Die Pyrrolizidin‐Alkaloide aus Senecio alpinus (L.) SCOP., S. subalpinus KOCH und S. incanus L. subsp. carniolicus, (WILLD.) BR.‐BL. Pyrrolizidin‐Alkaloide, 13. Mitteilung
Authors: Klásek A. , Reichstein T. , Šantavý F.
Published: December 2004

Senecio alpinus (L.) SCOP. is very rich in alkaloids. The dried overground parts gave 0,45% crude alkaloid mixture. The main component is seneciphylline (1); small amounts of cristalline jacozine (4) could also be isolated. ‐ Senecio subalpinus KOCH gave 0,368% of crude alkaloid mixture. In contrast to former results only 0,1% of this was present in the form of N‐oxides. The bulk was a ca. 1 : 1 mixture of seneciphylline with senecionine (3). ‐ Senecio incanus L. subsp. carniolicus (WILLD) BRä.‐BL. gave 0,40% of crude alkaloid mixture; from this some pure seneciphylline could be isolated. ‐ In all three plants the presence of integerrimine (2) and other non‐identified alkaloids could be established by thin layer chromatography.
Modifikationen von Antibiotika. 2. Mitteilung [1]. Über die Darstellung von 7‐Amino‐cephalosporansäure
Authors: Fechtig B. , Peter H. , Bickel H. , Vischer E.
Published: December 2004

7‐Aminocephalosporanic acid or esters thereof are prepared either by intramolecular aminolysis of esters of the antibiotic cephalosporin C or vïa imino‐ethers derived from the latter.

A simple procedure for the preparation of 7‐aminocephalosporanic acid in high yield is described.