bluuebunny/crossref_metadata_2025 huggingface dataset:
Dosage de traces d'hafnium dans l'aluminium par activation neutronique
Authors: Balsenc L. , Haerdi W.
Published: December 2004

Three methods are proposed for the assay of traces of hafnium in aluminium metal by neutron activation analysis. In the first method, the isotope 179mHf (T = 19 s), produced is counted after anionic resin exchange‐separation in sulfuric acid medium. The two other methods, which are non‐destructive, are based on the formation of 180mHf (T = 5,5 h) and 179mHf (T = 19 s). The latter method comprises an instrumental separation.
Inhaltstoffe der Wurzeln von Margaretta rosea Oliv. Glykoside und Aglykone, 323. Mitteilung
Authors: Sierp D. , Stöcklin W. , Reichstein T.
Published: December 2004

The roots of Margaretta rosea Oliv., subsp. rosea Bullock contain cardenolides mixed with Kedde negative ester glycosides. 6 Cardenolides were identified by paper chromatography (PC) and thin layer chromatography (TLC). Three of them were free aglycones (uzarigenin (1), corotoxigenin (3) and coroglaucigenin (5), the other three their corresponding 6‐deoxy‐β‐D‐allo‐pyranosides (ascleposide (2), gofruside (4) and frugoside (6). Only two cardenolides (1 and 5) were isolated in crystalline form. The behaviour of the more polar portion of the glycoside mixture shows that D‐gluco derivatives of at least 5 of the 6 cardenolides mentioned were also present.

The Kedde. negative glycosides were a complicated mixture containing mainly 2,6‐dideoxysugars linked to esterified polyhydroxy‐pregnanes. After mild acid hydrolysis cymarose, oleandrose and digitoxose could be identified by PC and TLC. From the crude aglycone portion only one cristalline genin (M) could be isolated. This was still a mixture, but its main component according to the mass spectrum was a monobenzoyl derivative C28H38O7. ‐ A small amount of cristalline O‐acetyl‐β‐amyrin was isolated from the least polar components.
Katalysierte Nitrilreduktionen mit Natriumborhydrid
Authors: Egli Robert A.
Published: December 2004

The reduction of benzonitrile with sodium borohydride in aqueous methanol in the presence of Raney nickel as a catalyst provides high yields of benzylamine as compared with the known low yields in the absence of Raney nickel. An explanation is proposed. Butyronitrile gives similar good yields of n‐butylamine.
Synthese der isomeren 3, 4‐Dimethyl‐4‐phenyl‐3, 4‐dihydro‐carbostyrile
Authors: Schmutz J. , Künzle F.
Published: December 2004

Cyclisation of 2‐methyl‐3‐phenyl‐but‐3‐en‐anilide (III) with polyphosphoric acid gave cis‐3, 4‐dimethyl‐4‐phenyl‐3, 4‐dihydro‐carbostyril (VII) in 61% yield together with a small amount of 2, 3‐dimethylindenone (VIII), whereas with AlCl3 a phenyl group was split off to give 3, 4‐dimethylcarbostyril (VI). The anilide III isomerises to cis‐ and trans‐2, 3‐dimethyl‐cinnam‐anilide (IV resp. V) under basic conditions.

The anilides IV and V gave only small yields of the dihydrocarbostyril VII with polyphosphoric acid. Chlorination of VII in position 3 using PCl5 yielded IX which, on splitting out HCl, gave 3‐methylene‐4‐methyl‐4‐phenyl‐3, 4‐dihydro‐carbostyril (X). X was converted to trans‐3, 4‐dimethyl‐4‐phenyl‐3, 4‐dihydro‐carbostyril (XI) by catalytic hydrogenation.
Séparation des terres rares par chromatographie sur échangeurs d'ions II. Séparation et analyse de la paire europium‐gadolinium [1]
Authors: Brunisholz G. , Roulet R.
Published: December 2004

A displacement chromatography technique is described for the separation of europium and light rare earths using the eluent ethylene‐diaminetetraacetate buffered by ammonium acetate giving a determined pH in the separation columns. This method gives concentrations up to 20 g of pure rare earth oxides per liter of eluate. A chromatographic method of analysis of europium in presence of other rare earths is also described.
Thermisches Verhalten von o‐Dipropenylbenzol, Beispiel einer aromatischen [1,7]‐sigmatropischen H‐Verschiebung. Vorläufige Mitteilung
Authors: Heimgartner[1] H. , Hansen H.‐J. , Schmid H.
Published: December 2004

cis, cis‐, cis, trans‐ and trans, trans‐o‐Dipropenylbenzene (cis, cis‐, cis, trans‐ and trans, trans‐1) were prepared. At 225° cis, cis‐1 isomerises to give cis, trans‐1 and vice versa. The isomerisation follows 1. order kinetics. At equilibrium 89% cis, trans‐ and 11% cis, cis‐1 are present. It is shown by deuterium labelling that the isomerisation is due to aromatic [1, 7 a] sigmatropic H‐shifts. trans, trans‐1 rearranges at 225° to yield 2, 3‐dimethyl‐1, 2‐dihydronaphthalene (3). This can be visualized by disrotatory ring closure of trans, trans‐1 followed by an aromatic [1, 5 s] H‐shift. When cis, cis‐ or cis, trans‐1 are heated for 153 hrs at 225° a small amount (3%) of 1‐ethyl‐1,2‐dihydronaphthalene (5) is formed.
Utilisation d'ylides du phosphore non stabilisés en chimie des sucres. V. Sucres ramifiés dérivés du méthyl α‐D‐lyxo‐hexopyrannosul‐4‐oside. Communication préliminaire
Authors: Tronchet J. M. J. , Chalet J. M.
Published: December 2004

Cis and trans‐methyl‐4‐deoxy‐2, 3‐O‐isopropylidene‐6‐O‐methyl‐4‐methylthio‐methylene‐α‐D‐lyxo‐hexopyra‐nosides are prepared by a Wittig reaction. Methods are described for the determination of the configuration of the geometrical isomers whose Raney‐Nickel reduction leads to derivatives of 4‐deoxy‐4‐methyl‐hexoses of the D‐manno and D‐talo series.
Die Synthese des corticotrop hochaktiven [1‐D‐Serin, 17, 18‐dilysin]‐β‐corticotropin‐(1‐18)‐octadecapeptidamids
Authors: Riniker B. , Rittel W.
Published: December 2004

A synthesis is described of [1‐D‐serine, 17, 18‐dilysine]‐β‐corticotropin‐(1–18)‐octadecapeptide amide (I), a short chain ACTH analogue which has been found to possess in animals and also in man high and prolonged corticotropic activity. Synthesis was carried out by the fragment condensation approach involving, in the last build‐up step, coupling of the protected sequences 1–10 and 11–18. From the protected octadecapeptide derivative 1–18 the free peptide was obtained in high yield by acidolysis.
Structure et synthèse de la damascénone (triméthyl‐2,6,6‐trans‐crotonoyl‐1‐cyclohexadiène‐1,3), constituant odorant de l'essence de rose bulgare (rosa damascena Mill.
Authors: Demole E. , Enggist P. , Säuberli U. , Stoll M. , Sz. Kováts E.
Published: December 2004

Damascenone

DORICENONE (trade mark applied for by Firmenich & Cie, Geneva).

an odoriferous ketone isolated in minute amounts from Bulgarian rose oil (Rosa damascena Mill.) is shown to be trans‐2,6,6‐trimethyl‐1‐crotonoyl‐cyclohexa‐1, 3‐diene (I). A synthesis starting from beta;‐cyclocitral is described for this conspicuous constituent of rose oil, which displays a powerful fragrance. The synthesis of four related, more saturated ketones, damascones

DORINONE (trade mark applied for by Firmenich & Cie, Geneva).

, is also described.
Komplexe mit makrocyclischen Liganden I. Mechanismus der Komplexbildung zwischen Ni2+ und 1,4,8,11‐Tetraazacyclotetradecan
Authors: Kaden T. H.
Published: December 2004

The kinetics of the formation of the NiII‐complex with 1,4,8,11‐tetraazacyclotetradecan (Cyclam) are studied by spectrophotometric and potentiostatic methods. The reaction of Ni2+ with the cyclic ligand is about 30000 times slower than with the open chain triethylenetetraamine (Trien). Therefore the rate determining step with Cyclam can not be the dissociation of the first coordinated water molecule, as it is usually in complexation reactions, but it must be the formation of the second coordinative bond. This is considered to be due to the more rigid structure of Cyclam in comparison with Trien.
Zur Abscheidung von Antimon und Wismut auf Goldelektroden
Authors: Schmidt E. , Gygax H. R. , Cramer Y.
Published: December 2004

The electrodeposition of Sb and Bi on gold electrodes from HCl solutions was studied using a voltammetric thin layer technique. The metal deposition is preceded by the formation of cation adsorption monolayers. Alloy formation could not be observed.
Die Photoelektron‐Spektren von CH3CHtCHCH3, CH3NtCHCH3, CH3NtNCH3, ein Beitrag zur Frage nach der Wechselwirkung zwischen den einsamen Elektronenpaaren der trans‐konfigurierten Azogruppe [1]
Authors: Haselbach E. , Heilbronner E.
Published: December 2004

A correlation of the photoelectron spectra of trans‐2‐butene, trans‐acetaldehydemethylimin and trans‐azomethane shows that the split Δ = ε (ag(n))−ε (bu(n)) between the lone pair orbitals ag(n) and bu(n) of trans‐azomethane amounts to 3.3 ± 0.2 eV. Molecular orbital calculations by the MINDO/1 procedure indicate that ag(n) lies above bu(n). In agreement with the experimental results the π‐orbital au(π) is predicted to fall into the interval between ag(n) and bu(n).
Isolierung und Struktur der Antibiotica Phomin und 5‐Dehydrophomin
Authors: Rothweiler W. , Tamm Ch.
Published: December 2004

From cultures of a Phoma species (strain S 298) (Fungi imperfecti) two new antibiotics, phomine (1) and 5‐dehydrophomine (4) have been isolated. Phomine and 5‐dehydrophomine represent a novel type of macrolide antibiotics, the large lactone ring being fused to a highly substituted octahydro‐isoindole system. Both show cytostatic activity.
Die Stereospezifität der Alkoholdehydrogenase
Authors: Bally C. , Leuthardt F.
Published: December 2004

The glyceraldehyde formed by oxidation of glycerol through alcohol dehydrogenase (E.C. 1.1.1.1) from horse liver has been condensed with phosphodihydroxyacetone using either rabbit muscle or liver aldolase. The single product was identified after silylation by gas chromatography as L‐sorbose‐1‐phosphate. No D‐fructose‐1‐phosphate was detected. Apparently liver alcohol dehydrogenase oxidizes glycerol stereospecifically to L‐(−)‐glyceraldehyde. Thus, the earlier conclusions of Hadorn et al. from chromatography of the borate complexes on Dowex 1 have been confirmed. The same stereospecific behavior was found for both isoenzymes III and IV.

With Bis‐(trimethylsilyl)‐trifluoroacetamide L‐sorbose‐1‐phosphate and D‐fructose‐1‐phosphate are persilylated. Two trimethylsilyl groups are bound to the phosphate group. These bonds are not cleaved during gas chromatography.
Recherches dans la série des cyclitols XXXVIII Etudes conformationnelles de dérivés cyclopenténiques disubstitués‐3, 5
Authors: Cocu F. G. , Wolczunowicz G. , Bors L. , Posternak Th.
Published: December 2004

Cyclopentenones substituted in position 4, and 3, 5‐cis or ‐trans disubstituted cyclopentenes have been studied by NMR. and by IR. spectroscopy. Cyclopentenone derivatives and cyclopentene derivatives adopt a quasi‐coplanar and an envelope conformation, respectively. The preferential orientation of the substituents has been established according to their nature and to the solvents by correlation to the vicinal and the long‐range coupling constants.
Synthese der 2‐Thio‐D‐glucose und einiger 3‐Thio‐D‐altrose‐Derivate
Authors: Hardegger E. , Schüep W.
Published: December 2004

Die Umsetzung von Natriumbenzylmercaptid mit 1, 6‐2, 3‐Dianhydro‐β‐D‐mannopyranose (IV) führte vorwiegend unter diäquatorialer Öffnung des 2, 3‐Epoxidringes zur 1, 6‐Anhydro‐3‐desoxy‐3‐benzylthio‐β‐D‐altropyranose (XV) und unter diaxialer Öffnung desselben Ringes zur 1, 6‐Anhydro‐2‐desoxy‐2‐benzylthio‐β‐D‐glucopyranose (V). Von den beiden Thio‐Derivaten V und XV wurden mehrere z. T. bekannte Umwandlungsprodukte hergestellt, die in Kombination mit physikalischen Messungen die eindeutige Strukturaufklärung der erwähnten Verbindungen ermöglichten und erstmals zur Synthese der krist. als β‐Pyranose formulierten 2‐Thio‐D‐glucose (XIV) führten.
Die Tautomeriegleichgewichte von Dihydrochinoxalinen
Authors: Schellenberg M.
Published: December 2004

The primary product of the two step reduction of 2‐phenylquinoxaline is the 1,4‐dihydrocompound which undergoes a tautomeric rearrangement to the thermodynamically more stable 1,2‐dihydro‐3‐phenylquinoxaline. The 1,4‐dihydro compound is an extremely reactive reducing agent whereas the 1,2‐dihydro form is almost inert against oxidizing agents. Both dihydro forms are in a kinetically hindered equilibrium. The rearrangement requires a transfer of a proton from a nitrogen to a carbon atom and is therefore relatively slow even at pH 0.

The 1,2‐dihydro compound cannot take part in redox reactions directly. If this compound is oxidized, the rate determining step is always the reversed tautomeric rearrangement.

The effect of the kinetics of the tautomeric rearrangement on the polarographic behavior of the 2‐phenylquinoxaline system is discussed.
Über die Reaktion von Schwefel mit Aminen und Formaldehyd. Eine neue Methode zur Herstellung von Thioformamiden und Dithiocarbamaten
Authors: Maier Ludwig
Published: December 2004

The reaction of sulfur with primary or secondary amines and formaldehyde has been studied. A simple one step process for the preparation of thioformamides (RR′NCHS; R  H, R′  CH3, C2H5; R  R′  CH3, C2H5; R+R′  (CH2), (CH2), C2H4OC2H) and the amine salts of N, N‐dialkyl‐dithiocarbamic acids (R2NCS2 · H2NR2, R  CH3, C2H5, C4H9; R2  (CH2), (CH2), C2H4OC2H) is reported. In addition, the isolation of diethylamidosulfoxylic acid, (C2H5)2NSOH · 1/2 H2O, the first derivative of a new class of compounds, is described. The physical properties and the 1H‐NMR. spectra of the above mentioned compounds are given.
L'action de l'ammoniac sur l'hydroxyde de cobalt(II) et la stabilité des complexes en milieu aqueux
Authors: Gübeli A. O. , Hébert J. , Taillon R. , Côté P. A.
Published: December 2004

From the solubility of precipitated Co(OH)2 (s) determined radiometrically as a function of pH and ammonia content of the heterogeneous systems, the formation constants have been obtained for the following mononuclear hydroxo‐, ammine‐ and mixed hydroxo‐ammine‐complexes: Co(OH)2, Co(OH)3−, Co(NH3)22+, Co(NH3)32+, Co(NH3)42+ and Co(OH)2 (NH3)2. The solubility of cobalt(II) hydroxide has also been calculated. The medium was 1M NaClO4 and the temperature 25° C.
Stereochemistry of the σ‐Complex Intermediate in Sterically Hindered Electrophilic Aromatic Substitutions. (20th communication on diazo coupling reactions)
Authors: Snyckers F. , Zollinger H.
Published: December 2004

The kinetics of the diazo coupling reactions of diazotized sulfanilic acid with 9 derivatives of 2‐naphthol, each containing a substituent in the 8‐position, have been measured. The reactions proceed by general base catalysis. The rate constants (k1) for the formation of the steady‐state intermediate in the presence of varying concentrations of a base (pyridine) have been evaluated from rate measurements. Similarly the ratios k2/k1 (where k2 is the rate constant for proton transfer from the steady‐state intermediate to the base, and k−1 is the rate constant for the dissociation of the intermediate) have been determined. The dependence of logk1 on σ+m and of the ratio k2/k−1 on a steric parameter Rf (defined in this paper) is interpreted as evidence for the steady‐state intermediate existing as a benzodienone σ‐complex with the sp3‐bound hydrogen in a pseudo‐equatorial position and the electrophile pseudo‐axial. A sterically caused destabilisation of the intermediate can be excluded. The steric influence on the ratio k2/k−1 is therefore due to the steric influence on k2 only. Diazo coupling of 8‐(2′‐pyridyl)‐2‐naphthol is subject to intramolecular base catalysis, as demonstrated by kinetic hydrogen isotope effects.
Herstellung der 1‐Thio‐D‐chinovose
Authors: Schüep W. , Hardegger E.
Published: December 2004

Aus β‐Pentaacetyl‐D‐glucose wurde unter Variation und methodischer Verbesserung der Reaktionsbedingungen über die bekannten Zwischenprodukte II, III, IIIa die eben‐falls bekannte α‐Acetobro n‐D‐chinovose (IV) hergestellt. Der Übergang in die 1‐Thio‐D‐chinovose‐Reihe, V, Va, VI bis VIc, erfolgte in durchwegs sehr guten Ausbeuten aus der Acetohalogenose IV mit Kalium‐äthylxanthogenat und Folgeraktionen, bzw. mit Kaliumthioacetat. Die krist., wenig beständige 1‐Thio‐D‐chinovose wurde als β‐Pyranose VIa formuliert.
Thermal Interconversion of Phenylcarbene and Tropylidene. Preliminary communication
Authors: Wentrup C. , Wilczek K.
Published: December 2004

Phenylcarbene and tropylidene interconvert in the gas‐phase, as evidenced by the formation of stilbene and heptafulvalene (5) from both at 300°. Heptafulvalene itself rearranges to stilbene and anthracene above 500°. Phenylcarbene, but not tropylidene, undergoes ring contraction to fulvenallene (9) at 900°. Formation of fluorene from diphenylcarbene involves a complete ring expansion to 2‐phenyltropylidene (14), and subsequent ring contraction to 2‐biphenylylcarbene (15).
Utilisation d'ylides du phosphore non stabilisés en chimie des sucres VI. Sucres ramifiés dérivés des di‐O‐isopropylidène‐1,2:5,6‐α‐D‐ribo‐et‐α‐D‐xylo‐hexofurannosul‐3‐oses
Authors: Tronchet J. M. J. , Bourgeois J. M.
Published: December 2004

The cis and trans isomers of 3‐deoxy‐1,2:5,6‐di‐O‐isopropylidene‐3‐C‐methylthiomethylene‐α‐D‐xylo‐ and ‐α‐D‐ribo‐hexofuranoses have been prepared by treatment of 1,2:5,6‐di‐O‐isopropylidene‐α‐D‐xylo‐ and ‐α‐D‐ribo‐hexofuran‐3‐uloses with methylthiomethylene‐triphenylphosphorane. Configurations are assigned by NMR. A new type of 4J is described. Hydrogenation‐desulfurization of the methylthiovinylic sugars affords 3‐deoxy‐3‐methyl sugars of the D‐allo, D‐gulo, and D‐galacto series. Derivatives of 3‐deoxy‐3‐methyl‐D‐lyxose and 3‐deoxy‐3‐methyl‐D‐ribose are prepared by chain‐shortening of derivatives of the corresponding 3‐deoxy‐3‐methyl‐hexoses.
Zur Stereochemie der thermischen Fragmentierung von Hydrazonderivaten substituierter N‐Amino‐aziridine. Vorläufige Mitteilung
Authors: Müller Robert K. , Felix Dorothee , Schreiber J. , Eschenmoser A.
Published: December 2004

The thermally induced fragmentations of the hydrazones derived from phenylglyoxal and the diastereomeric 2,3‐diphenyl‐1‐amino‐aziridines and 2,3‐dimethyl‐1‐amino‐aziridines proceed with high stereospecificity.
études sur les composés organométalliques, VIII. Synthése du tétrabenzyltitane
Authors: Jacot‐Guillarmod André , Tabacchi Raffaele , Porret Jacques
Published: December 2004

Tetrabenzyltitane is prepared by reaction of TiCl4 on dibenzylmagnesium in pentane or hexane at – 20° in the presence of a small amount of ether.
Pyramidal Inversion in Cyclic Sulfonium Salts
Authors: Garbesi A. , Corsi N. , Fava A.
Published: December 2004

5‐ and 6‐membered cyclic sulfonium salts carrying methyl substituents on the ring have been synthetized and partially resolved. These salts undergo thermal stereomutation at rates which are 103 times lower than that of non‐cyclic sulfonium cations. Very stringent evidence is presented that racemisation or, where the case may be, epimerisation takes place by pyramidal inversion of the sulfur atom.
Cardenolide aus dem chinesischen Krötengift Ch'an Su. Über Krötengifte, 35. Mitteilung
Authors: Höriger Niklaus , Linde Horst H. A. , Meyer Kuno
Published: December 2004

From the toad venom Ch'an Su the cardenolides I, III and V have been isolated. It is the first time that cardenolides and bufadienolides are detected simultaneously in a biological material.
Recherches dans la série des cyclitols XXXIX RMN. de protons d'hydroxyles de cyclopentane‐ et de cyclopentène‐polyols
Authors: Cocu F. G. , Wolczunowicz G. , Bors L. , Posternak Th.
Published: December 2004

Several mono‐, di‐, and tri‐hydroxy derivatives of cyclopentane and cyclopentene have been studied by NMR. spectroscopy. The chemical shifts and the coupling constants of the OH groups have been correlated with their position, with their configuration and, in some cases, with their conformation.
Bilirubinkonjugate der menschlichen Galle: Ausscheidung als Acylglykoside von Aldobiouron‐, Pseudoaldobiouron‐ und Hexuronosylhexuronsäuren
Authors: Kuenzle Clive C. , Rüttner Jacques R. , Eugster Conrad Hans
Published: December 2004

Die Bilirubinderivate der menschlichen Galle wurden in Form ihrer Phenylazoverbindungen isoliert und durch mehrfache Verteilungschromatographie mit umgekehrten Phasen in 8 Fraktionen aufgetrennt (Azopigmente A1, A2 und B1 bis B6). Der Hauptanteil des Bilirubins erscheint in der Galle nicht wie bisher angenommen als Glucuronid, sondern als Acylglykoside von Aldobiouron‐, Pseudoaldobiouron‐ und Hexuronosylhexuronsäuren. Für die Hauptkomponenten schlagen wir die folgenden vorläufigen Strukturen vor (acyl = Acylrest des Aglykons):

Acyl‐(6‐O‐hexopyranosyluronsäure‐hexosid)

Acyl‐(4‐O‐hexofuranosyluronsäure‐glucosid)

Acyl‐(4‐O‐β‐D‐glucofuranosyluronsäure‐glucosid)

Acyl‐(4‐O‐(α‐D‐glucofuranosyl)‐β‐D‐glucosiduronsäure)

Acyl‐(4‐O‐(3‐C‐hydroxymethyl‐ribofuranosyluronsäure)‐β‐D‐glucosiduronsäure)

.
Chemical Structure Studies of Cow ϰ‐Casein: Study of the soluble tryptic peptides
Authors: Jollès Jacqueline , Alais Charles , Jollès Pierre
Published: December 2004

The sequences of 13 tryptic peptides of cow ϰA‐casein (accounting for about one half of the amino acid residues present in the protein) were established. The rennin sensitive linkage could be located in a large fragment (36 residues). ϰ‐casein consists of a hydrophilic part (ϰ‐caseino‐glycopeptide) and of a hydrophobic moiety (para‐ϰ‐casein); in this latter, however, several quite hydrophilic sequences were characterized. Another feature of the ϰ‐casein structure is the frequent duplication or triplication of certain amino acids (Pro‐Pro; Phe‐Phe; Gln‐Gln‐Gln‐Asn‐Glu‐Glu‐Glu; Pro‐Pro‐Lys‐Lys‐Asn‐Gln‐; etc. …).
Die Koordinationszahl von Lanthaniden: Thermodynamik der LnIIIEDTA‐Mischkomplexe mit den Anionen der 8‐Hydroxychinolin‐5‐sulfonsäure, Iminodiessigsäure und Nitrilotriessigsäure
Authors: Geier G. , Karlen U.
Published: December 2004

The values of ΔG, ΔH and ΔS for the formation of the mixed 1:1:1 lanthanide EDTA complexes with the anions of 8‐hydroxyquinoline‐5‐sulfonic acid, iminodiacetic acid and nitrilotriacetic acid were determined by pH‐titrations and a direct calorimetric method. These thermodynamic data are discussed and compared with those for the formation of the Ln(III)EDTA complexes. Contrary to current opinion it is concluded that all trivalent lanthanide aquoions have the same coordination number in dilute solution. However, in the series of the lanthanide EDTA complexes the coordination number changes between Sm and Tb. In this region, equilibria occur between two types of EDTA complexes with different numbers of coordinated water molecules:

equation image

The corresponding equilibrium constants could be evaluated. The coordination number changes also in many other Ln complexes along the lanthanide series, and similar equilibria occur.
Pyrolysen‐ und Hydrierungsversuche in der Elemol‐ und Dihydrogeijeren‐Reihe
Authors: Ganter C. , Keller‐Wojtkiewicz Frau B.
Published: December 2004

The pyrolysis of elemol (1) in the presence of benzoic or p‐nitrobenzoic acid, and of elemyl‐p‐nitrobenzoate (3) was studied. From the many products formed, the compounds 6, 7, 8, 10, 11, 14, 15 and 18 were isolated and identified. On the basis of systematic experiments in the elemol (1) and dihydrogeijerene (26) series the sequence of the formation of these products could be determined. Several factors influencing the compositions of the pyrolysis mixtures are discussed.

The products of pyrolysis of both series [elemol (1) and dihydrogeijerene (26), respectively] were catalytically hydrogenated, yielding the saturated hydrocarbons 34, 35–37, and 38–40, respectively.

The synthesis of racemic dihydrogeijerene (26) was achieved starting from germacrone (41).
Beiträge zur Chemie des 4,5‐Dihydro‐10H‐benzo [5, 6]cyclohepta[1,2‐b]thiophens
Authors: Bastian J. M. , Ebnöther A. , Jucker E. , Rissi E. , Stoll A. P.
Published: December 2004

Several syntheses of 4,5‐dihydro‐10 H‐benzo[5,6]‐cyclohepta[1, 2‐b]thiophen‐10‐one (I b) are described. The pharmacological properties of the compounds XIII, which derive from IB through basic substitution on position 10, are briefly mentioned.
Über den Verteilungssatz der Auxochrome bei Azokörpern, III Azokörper mit zueinander p‐ständigen Auxochromen
Authors: Kokkinos K. , Wizinger R.
Published: December 2004

It is shown with some derivatives of 2‐hydroxy‐azobenzene and 2‐hydroxy‐4 nitro‐azobenzene that — in conformity with the rule of repartition — auxochromes in p‐position have a strong bathochromic effect.
Base‐Catalysed H‐D Exchange in 1 ‐Methylthiolanium Iodide
Authors: Barbarella G. , Garbesi A. , Fava A.
Published: December 2004

The kinetics of the base‐catalysed H/D exchange of the 1‐methylthiolanium cation in heavy water has been studied. Of the four α‐methylene protons, two exchange much faster than the other two, a result which requires that reprotonation of the carbanion intermediate occurs with retention of configuration. NMR. spectral analysis indicates that the protons undergoing faster exchange bear a trans relation to the lone‐pair on sulfur. This conclusion appears to conform to Wolfe's theory on the stability of carbanions [3].
Rapid Syntheses of Hexa and Heptahelicene
Authors: Martin R. H. , Marchant Marie‐Jeanne , Baes M.
Published: December 2004

A two‐step synthesis of hexahelicene (scheme 1; 53% over‐all yield), a three‐step synthesis of hexaheliene (scheme 2; 33% over‐all yield), and a two‐step synthesis of heptahelicene (scheme 3; 14% over‐all yield) are described.
Cystinpeptide aus (S‐Acetamidomethyl‐cystein)‐peptiden durch Oxydation mit Jod: Die synthese von cyclo‐L‐cystin
Authors: Kamber B.
Published: December 2004

The conversion of S‐acetamidomethyl cysteine peptides to by a reaction with iodine is described. The method is applied in the synthesis of the hitherto unknown cyclo‐L‐cystine. The structure of this compound was confirmed by molecular weight determination, NMR. and mass spectroscopy.
Harmoniques des vibrations de valence CH dans les alcanes et les halogénures de t‐butyle
Authors: Avanessoff M. , Gäumann T.
Published: December 2004

The first and second harmonic CH and CD valence vibrations of alkanes and t‐butyl halides have been measured. A model is proposed for the methyl and methylene groups, which allows the calculation of the anharmonicity constants of every vibrational mode and of the couplings between the modes. The already known large values (−100 to −150 cm−1) for the anharmonicity constants that couple the symmetrical with the asymmetrical modes are confirmed. As compared with lower harmonics combination bands become predominant for the higher ones; they allow the application of a diatomic model to estimate higher harmonics and the energy of dissociation.
Etude de composés d'addition d'acides de Lewis, XXXIV [1] Composés d'addition de benzoquinone‐1, 4 avec TiCl4
Authors: Giallonardo R. , Susz Bernard‐P.
Published: December 2004

The adduct 1,4‐benzoquine · TiCl4 has been prepared in CH2Cl2 solution at about −60°. Its IR. spectrum has been recorded at the same temperature. The experimental study of the vibrational frequencies has been completed by the calculation of the fundamental vibrations in the molecular plane, using Wilson's FG method, with slightly simplified models of 1,4‐benzoquinone · TiCl4 (13 masses) and 1,4‐benzoquinone · 2 TiCl4 (14 masses); analysis by use of internal and symmetry coordinates. An assignment of most of the observed bands is proposed and the conclusion is reached that the complex, when solid, is (1,4‐benzoquinone · TiCl4)n.

The force constants F(CO) are 9,85 · 105 dyne/cm for the quinone and 8,8 · 105 dyne/cm for the disturbed carbonyl bond of the polymerized complex in the model proposed.

At ordinary temperature in benzene solution of the components the adduct 1,4‐benzoquinone. TiCl4 · benzene precipitated; with the help of the models, the fundamental vibrations of its IR. spectrum have been assigned.
Microcalorimetric Measurements with the Valinomycin ‐ Potassium Iodide Complex. Preliminary communication
Authors: Möschler Hans Jörg , Weder Hans‐Georg , Schwyzer Robert
Published: December 2004

Die Mikrokalorimetrie wurde erstmals zur Bestimmung von Assoziationskonstante, Reaktionsenthalpie, freier Reaktionsenergie und Reaktionsentropie der Komplexbildung zwischen Kaliumjodid und Valinomycin in Äthanol verwendet. Eine konstante Konzentration von Valinomycin (10−4M) wurde mit verschiedenen Konzentrationen von Kaliumjodid (10−5 bis 10−3M) versetzt. Die Enthalpieänderung (Grössenordnung 0,5 bis 5,0 mcal) wurde als Titrationsparameter benützt. Die Auswertung der Sättigungskurve nach Klopfenstein [3] ergab.
Note on the rôle of cyanides and polyphosphates in the formation of peptides in aqueous solutions of amino acids, at room temperature, as a possible prebiotic process
Authors: Rabinowitz Joseph
Published: December 2004

Les cyanures et les polyphosphates jouent un rôle important dans l'évolution chimique. Des solutions aqueuses d'acides aminés additionnées de trimétaphosphate et de cyanure, amenées à pH 11,5–12 par NH3 et maintenues à ce pH 4 jours à température ordinaire, contiennent les dipeptides correspondants, formés avec des rendements à peu près doubles de ceux obtenus en présence du seul trimétaphosphate. En présence uniquement de cyanure, il ne se forme pas de peptides. Dans ces mêmes conditions, une solution de cyanure ne fournit ni acides aminés ni peptides. Pour la formation abiotique de peptides à partir d'amino‐acides, le système polyphosphate‐cyanure est dono plus efficace que chacun de ses composants individuellement.
Détermination de constantes de formation des complexes phosphorescents du bore avec la benzoylacétone, à l'aide de durées de vie moyenne d'émission
Authors: Gamba G. , Marcantonatos M.
Published: December 2004

A method, based on mean life times (τ) of T → S emission, is proposed for the determination of stability constants of two successive mononuclear complexes and is applied to the boric acid‐benzoylacetone AB et AB2 phosphorescent complexes in glassy (77 K) ether‐concentrated sulfuric acid media. Results show that this method ‐ if not limited by very near τ values of the complexes – is precise and applicable even to cases where, at high ligand concentrations, filter effects intervene. The use of τ values by this procedure offers, over colorimetric and fluorometric methods, enhanced possibilities to determine the type of complexes formed and their stability.
Photochemical Reactions. Part 64 [1]. The photochemistry of 3‐alkyl‐cyclopent‐2‐en‐ones
Authors: Reinfried R. , Belluš D. , Schaffner K.
Published: December 2004

On ultraviolet irradiation in toluene, cyclopent‐2‐en‐one (1a) and 3‐methylcyclopent‐2‐en‐one (1b) undergo dimerisation (→ 3a, b, 4b), whereas 3‐t‐butyl‐cyclopent‐2‐en‐one (1e) and the bicyclo [3.2.1]octenone 2a only react with the solvent (→ 5e–7e, 8–10). The 3‐ethyl‐(1c) and 3‐isopropyl‐cyclopent‐2‐en‐ones (1d) afford by dimerisation products 3c, d, 4c and by reaction with the solvent 5c, d, 6c, d, 7d. The β‐methoxy‐enones 1f and 2b are unreactive under comparable irradiation conditions. The head‐to‐head cyclobutane dimer 3b (HH) by separate irradiation at < 3400 Å in toluene, is reconverted to 1b. By similar irradiation each of the head‐to‐tail dimers 3b (anti‐ and syn‐HT) and also the unsaturated dimer 4b give a new isomer of unknown structure besides small amounts of monomer 1b and relatively large amounts of insoluble material.

The photoreactions of 1b‐e can be quenched by naphthalene. Stern‐Volmer plots for the quenching of the dimers of 1b, 1c, and 1d, and of 3‐t‐butylcyclopentanone (5e) and the dihydro dimer 7e are linear and within each experiment, the slopes satisfactorily coincide, whereas the slope for the α‐benzyl ketone 6c is distinctly greater than that for the dimers 3c. A similar differentiation, although less pronounced, is found between the benzyl ketones 6d and 6e and the respective accompanying products.
The photoelectron spectrum of thiazyl fluoride (NSF)
Authors: Cowan D. O. , Gleiter R. , Glemser O. , Heilbronner E. , Schäuublin J.
Published: December 2004

The photoelectron spectrum of thiazyl fluoride has been recorded. An assignment of the first five bands has been attempted, using semi‐empirical calculations.
Synthesis and Absolute Configuration of Cryptostylines I, II, and III
Authors: Brossi A. , Teitel S.
Published: December 2004

Die Darstellung der drei optisch aktiven natürlichen Alkaloide Cryptostyline I, II und III aus Cryptostylis fulva Schltr. und ihrer drei unnatürlichen Antipoden wird beschrieben. Es wird gezeigt, dass die drei natürlichen Cryptostyline S‐Konfiguration besitzen. Die berichtete leichte Racemisierbarkeit der natürlichen Cryptostyline wird auf optische Unreinheit der ursprünglichen Präparate zurückgeführt.
Pyrrolidide als Derivate für die Strukturaufklärung aliphatischer und alicyclischer Carbonsäuren mittels Massenspektrometrie
Authors: Vetter W. , Walther W. , Vecchi M.
Published: December 2004

The pyrrolidide group is, in contrast to the carboxy‐ and ester groups, capable of inducing strong electron impact fragmentation at the b̃‐ and γ‐bonds in complicated alicyclic and aliphatic compounds. The fragments so formed allow certain conclusions concerning the structure in the neighbourhood of the functional group.
Evidence for a synfacial nucleophilic displacement with allylic rearrangement. Mechanistic conclusions. Preliminary communication
Authors: Jefford C. W. , Sweeney A. , Hill D. T. , Delay F.
Published: December 2004

Reduction of exo‐2‐methyl‐3, 4‐dichlorobicyclo[3.2.1]oct‐2‐ene and the exo‐2‐phenyl‐3,4‐dibromo analogue with lithium aluminium hydride proceeds mainly with allylic rearrangement. Moreover, hydride enters and bromide leaves synfacially. The stereochemistry of the process is discussed in the light of the favourable energy of a quasi‐cyclic transition state in which reagent and halide are complexed.
Hydroxyalkylation d'hydantoínes monocycliques au moyen de composés époxydés
Authors: Porret D. , Habermeier J.
Published: December 2004

Par réaction entre hydantoines monocycliques et substances monoépoxydées comme l'oxyde d'éthylène dans des rapports moléculaires et des conditions appropriées, on obtient des produits hydroxyalkylés définis: les (hydroxy‐2‐alkyl)‐3‐hydantoïnes, bis‐(hydroxy‐2‐alkyl)‐1,3‐hydantoïnes et bis‐(hydroxyalkyl‐polyoxyalkyl)‐1,3‐hydantoïnes, quie sont des produits intermédiaires intéressants. Leur préparation et quelques‐unes de leurs propriétés sont étudiées.
Synthetic Studies on Damascenones
Authors: Büchi G. , Wüest H.
Published: December 2004

The odor principle β‐damascenone and its isomer α‐damascenone have been prepared by treatment of the corresponding ethyl safranates with excess allyl lithium followed by alkoxide catalyzed isomerization of the resulting products with β, γ‐unsaturated ketonic side chains. Addition of allyltriphenylphosphorane (preferably prepared from allyltriphenylphosphonium chloride) rather than the propenyl isomer to ethyl α‐isopropylidene‐acetoacetate produced ethyl α‐safranate. This represents a new, potentially general method for the synthesis of functionalized cyclohexadienes.
Die Struktur von Corchorosid B. Glycoside und Aglykone, 329. Mitteilung
Authors: Venkata Rao E. , Venkata Rao D. , Pavanaram S. K. , Von Euw J. , Reichstein T.
Published: December 2004

Corchoroside B has the empirical formula C29H42O8 and was found to be a L‐rhammoside of canarigenin (5), most probably the α, L‐rhamnopyranoside (1).
Indolo[3,3a,4‐gh]chinoline und 10a, 6a‐Iminopropanoindolo[3,3a,4‐gh] chinoline. Stereospezifische Synthesen und Umlagerungen. Teil I. 8. Mitteilung über synthetische Indolverbindungen
Authors: Stoll Andréea P. , Niklaus P. , Troxler F.
Published: December 2004

The stereospecific cyclization of derivatives of 1‐benzyl‐5‐oxo‐1,3,4,5‐tetrahydrobenzo[cd]indole to trans‐octahydroindolo[3,3a,4‐gh]quinolines 3 and 4 is described. The trans methyl esters (4b and 4c) were converted with BF3/CH3OH to the thermodynamically more stable cis‐epimers 5. The structures and stereochemistry of the products, deduced from chemical evidence and analysis of models, are compatible with the NMR. data.
Herstellung von ar‐Pentafluor‐L‐phenylalanin
Authors: Fauchère Jean‐Luc , Schwyzer Robert
Published: December 2004

An enzymatic resolution of ar‐pentafluoro‐DL‐phenylalanine is described. The L antipode has been isolated and its Nα‐t‐butoxycarbonyl derivative prepared.
The Electrocyclic Cyclopropyl‐Allyl Rearrangement. Preliminary communication
Authors: Haselbach E.
Published: December 2004

MINDO‐2 SCF calculations indicate that ring‐opening of cyclopropyl radical (I) to allyl radical (II) is more favourable via a disrotatory reaction path, the calculated activation energy being ∼30 kcal/mole. (For conrotatory opening the activation energy was found to be ∼44 kcal/mole.) The two critical motions of the nuclei during the transformation are found to be strongly decoupled, i.e. rupture of the CH2βCH2 bond precedes rotation of the CH2 groups. As predicted by qualitative theories both ring‐opening modes are unfavourable since they involve a change in electronic ground‐state symmetry between I and II. The preferred ring‐opening mode is discussed qualitatively in terms of Evans' principle.
The Interaction of Non‐bonding Orbitals in Dicarbonyls: Ab Initio Results on Glyoxal
Authors: Ha T.‐K. , Hug W.
Published: December 2004

Die energetische Lage der kanonischen Molekelorbitale von Glyoxal in der trans‐ und cis‐Konformation wurde durch ab initio‐Rechnungen bestimmt. Die Wechselwirkung der < nichtibindenden > Orbitale dieser Molekel wird diskutiert.
De la chimie des ptérines, 37e communication Mécanisme d'oxydation des tétrahydroptérines disubstituées en C(6) et localisation de l'électron célibataire chez les radicaux qui en découlent
Authors: Viscontini M. , Argentini M.
Published: December 2004

14C a été incorporé dans le groupe méthylène de la chaîne latérale de l'aminométhyl‐6‐méthyl‐6‐tétrahydro‐5,6,7,8‐ptérine. Oxydée à l'air dans des conditions physiologiques, cette substance fournit de l'aldéhyde formique et de la méthyl‐6‐ptérine radioactifs, dus respectivement à und dégradation de la chaîne latérale et à une ouverture du cycle tétrahydropyrazinique suivie de recyclisation. Cette observation est discutée au point de vue tant chimique que biologique.
Über Pterinchemie. 38. Mitteilung. Neue Synthesen von Folsäureanalogen
Authors: Viscontini M. , Bieri J.
Published: December 2004

Eine einfache Synthese des 6‐Formylpterins aus Neopterin wird beschrieben. Dieses isomerenfrei erhaltene Produkt wird als Edukt für die Herstellung von sehr reinen, isomerenfreinen Folsäureanalogen verwendet. Das 6‐Formylpterin wird mit p‐Aminoaryl‐Derivaten zu 6‐Azomethin‐pterinen kondensiert. Die CH  N‐Gruppierung lässt sich dann mit NaBH4 sehr leicht unter Bildung der entsprechenden Amino‐methyl‐pterinen reduzieren.
Komplexe mit makrocyclischen Liganden, II. Zweischrittmechanismus bei der Komplexbildung von Cu2+ mit meso‐5,7,7,12,14,14‐Hexamethyl‐1,4,8,11‐tetraazacyclotetradecan
Authors: Kaden Th. A.
Published: December 2004

The complex formation between CuII and the title compound (tet a) is studied by spectrophotometry and pH‐stat techniques. Between pH 4 and 5,5 the reaction proceeds in two steps, the first giving a blue intermediate, Cu(teta)2+ (blue), exhibiting a broad absorption band at 620 nm. Titration with NaOH and the absorption spectrum suggest that, in the intermediate, CuII is coordinated to only two amino groups of the ligand. Both steps are slow compared to other complex formation reactions of CuII. The rate of the first step, in which Cu(tet a)2+ (blue) is formed, is given by v1 = k1 · [Cu2+] [(tet a) H]/[H+] with k1 = 2,7 · 10−6 s−1 at 40° and I = 0,1. In the second step the last two nitrogens of the quadridentate ligand are bound to CuII, giving the mauve end product. The rate of this step is given by v2 = k2 · [Cu(tet a)OH+ (blue)] [OH−] with k2 = 1,2 · 103 M−1 s−1 at 50° and I = 0,5.
Die Dienol‐Benzol‐Umlagerung von Propargylcyclohexadienolen: aromatische [1,2]‐, [3,3]‐ und [3,4]‐sigmatropische Umlagerungen
Authors: Heimgartner H. , Zsindely J. , Hansen H.‐J. , Schmid H.
Published: December 2004

The acid catalysed dienol‐benzene rearrangement of methyl substituted o‐ and p‐propargylcyclohexadienols (18–22, 34 and 35) was investigated. In the first step water is eliminated to yield the corresponding methyl propargyl benzonium ions (cf. scheme 6, a), which undergo [1s, 2s] sigmatropic rearrangements to give propargylbenzenes (28, 29, 30, 38) and [3s, 4s] sigmatropic rearrangements to give allenylbenzenes (24–27, 40) (cf. schemes 2, 3, 5, 6). [3s, 3s] sigmatropic rearrangements occur only to a small extend. In the rearrangement of 2‐propargyl‐2,4,6‐trimethylcyclohexa‐3,5‐dien‐1‐ol (18) a [1s, 2s] sigmatropic methyl shift is observed (4%).
Formation and Reactivity of 1,3‐Dialuminium Alkanes
Authors: Stefani A. , Pino P.
Published: December 2004

The formation of 1,3‐dialuminium alkanes by auto‐addition or by hydro‐alumination of methallyl‐aluminium derivatives is reported. Some aspects of their thermal decomposition and of their reactivity are discussed.
Beitrüge zur Chemie der Si‐N‐Bindung, XXII N,N′‐Tetrakis(trimethylsilyl)methylendiamin
Authors: Fink Walter
Published: December 2004

N.N′‐Tetrakis‐Tetrakis(trimethylsilyl)methylenediamine is prepared by the reaction of lithium‐bis(trimethylsilyl)amide with tris(chloromethyl)amine.
Über die Synthese von in 1‐Stellung substituierten 4‐Nitro‐acridonen
Authors: Burdeska K. , Pugin A.
Published: December 2004

Diphenylaminecarboxylic acids can be prepared in high yields by reacting 1‐chloro‐3,4‐dinitrobenzene with anthranilic acids. The acridones obtained by ring closure of these diphenylaminecarboxylic acids represent valuable starting materials for the synthesis of disperse dyes and pigments.
Synthese von [2,7‐Cystin]‐Gramicidin S, einem künstlichen homodet‐heterodet‐bicyclischen Decapeptid
Authors: Ludescher Urs , Schwyzer Robert
Published: December 2004

The first synthesis of a homodetic‐heterodetic‐bicyclic polypeptide, [2,7‐cystine]‐gramicidin S, is described. For the protection of the C‐terminal carboxyl and the cysteine sulfhydryl functions, the 2‐(toluene‐p‐sulfonyl)‐ethyl‐ (Tsa) and the acetamidomethyl‐ (Acm) groups, respectively, were used. Stepwise synthesis from the C‐terminus, using Nα Boc‐amino acids, and selective removal of protecting groups yielded the two pentapeptide derivatives: Boc · Val‐Cys‐(Acm)‐Lem)‐Leu‐phe‐Pro · OH and H · Val‐Cys(Acm)‐Leu‐phe‐Pro · OTsa. They were condensed with dicyclohexyl‐carbodiimide and 1‐hydroxybenzotriazole to give the crystalline decapeptide Boc · [Val‐Cys(Acm)‐Leu‐phe‐Pro]2 · OTsa. Removal of the Tsa group by β‐elimination at pH 11.5 yielded the crystalline free acid, which was further converted (by treatment with di‐p‐nitrophenyl sulfite followed by TFA) to TFA, H · [Val‐Cys(Acm)‐Leu‐phe‐Pro]2 · ONp. Cyclization of the active ester in warm pyridine gave a mixture of (2,7‐bis‐S‐acetamidomethyl‐cysteine]‐gramicidin S (27% yield) and (2,7‐cysteine)‐gramicidin S (4%). The former compound was readily converted to the latter by treatment with I2 in MeOH. In the bicyclic peptide, the decapeptide ring is contained in a β‐type secondary structure, identical with that in gramicidin S; the disulfide bridge shows P‐helical chirality and gives rise to a negative Cotton effect at 271 nm [3].
Dérivés C‐glycosyliques VIII. Synthèse de C‐glycosyl‐3‐pyrazoles à partir d'une nitrilimine dérivée de l'anhydro‐2,5‐D‐ribose. Compétition entre cyclo‐additions dipolaires‐1,3 et cyclisations non concertés
Authors: Tronchet J. M. J. , Perret Melle F.
Published: December 2004

Several 3‐(2,5‐anhydro‐ribosyl)‐pyrazoles of potential medicinal interest have been synthesized by reacting alkynes or alkynylmagnesium bromides with the p‐nitrophenylhydrazone of 2,5‐anhydro‐ribonyl bromide. From a mechanistic standpoint, it has been shown that the sugar‐nitrilimine used in these studies reacts more readily as an electrophile than as a dipole. Thus, the hydrazonyl bromide gave exclusively the corresponding phenylethynylhydrazone when treated with phenylethynylmagnesium bromide and led to a 1:1 mixture of phenylethynylhydrazone and pyrazole when reacted with phenylacetylene. This proves that nucleophilic additions onto nitrilimines are much faster than Huisgen's 1,3‐dipolar cycloadditions.
Kinetic Salt Effect in the 18O‐Exchange Reaction between Bromate and Water
Authors: Gamsjäger H. , Baertschi P.
Published: December 2004

The kinetic salt effect in the 18O‐exchange reaction between bromate ion and water has been investigated at 60° in a range of ionic strength from 0.02M < I < 1.9M using NaNO3 or NaClO4 as inert salts. From the experimental data the following relation was deduced for the uncatalysed reaction path

In the H+‐catalysed reaction path the Brønsted‐Davies equation was obeyed up to I ⋍ 0.1M

At I > 0.8M the sign of Δ logk2/Δ I1/2 was positive. The theoretical interpretation of these results is consistent with the mechanistic evidence obtained previously from the rate law and the solvent isotope effects.
The Crystal and Molecular Structure of 3,5,7‐Triphenyl‐4H‐1,2‐Diazepine Picrate
Authors: Gerdil R.
Published: December 2004

The crystal structure of 3,5,7‐triphenyl‐4H‐1,2‐diazepine (monoclinic, a = 8.132, b = 13.180, c = 24.204 Å, β = 104.15°, space group P21/c. Z = 4) has been determined by X‐ray analysis. The 1,2‐diazepine ring adopts a boat conformation with a methylene group at the prow. The phenoxide group of the picrate moiety is bonded to one of the diazepine nitrogen atoms through an hydrogen bond.
Untersuchung über die Verteilung von Substanzen in Dünnschichtchromatogrammen
Authors: Seiler H.
Published: December 2004

Densitometric techniques are common for the in situ quantitative investigations of thin‐layer chromatograms. The present paper concernes investigations of the distribution of substances within their spots by the aid of radio‐isotopes. The distribution depends on the kind of adsorption mechanisms.
Valenzisomerisierung von cis‐dienonen IV. Die vier stereoisomeren Formen von 4‐Methyl‐6‐phenyl‐3, 5‐hexadien‐2‐on
Authors: Schiess P.
Published: December 2004

(Z,Z)‐4‐Methyl‐6‐phenyl‐3,5‐hexadien‐2‐one (5) is converted to its (Z,E)‐isomer 6 at 35° in the dark. This ready, uncatalysed cis,trans‐isomerization is shown to proceed through 2H‐pyran 9. Irradiation of either stereoisomeric dienone 6, 7 or 8 at 0° produces a photostationary mixture of 5, 6, 7 and 8 in which the (Z,Z)‐isomer 5 predominates.
Die Synthese von 4‐Alkylchinuclidinen. Chinuclidinreihe, 11. Mitteilung
Authors: Grob C. A. , Simon W. , Treffert W. D.
Published: December 2004

The syntheses of 4‐methyl‐, 4‐ethyl‐, 4‐isopropyl‐and 4‐t‐butylquinuclidine are described. The key step in the synthesis of 4‐t‐butylquinuclidine involves a modified Koch‐Haaf reaction leading from a δ‐amino‐tert. alcohol to an ester of the homologous acid.
Die physikalischen Eigenschaften der roten Augenpigmente aus Drosophila melanogaster, einer neuen Klasse atropisomerer Naturstoffe. Pteridine, LIII
Authors: Schlobach Heinrich , Pfleiderer Wolfgang
Published: December 2004

UV./VIS.‐, ORD.‐, CD.‐ and fluorescence spectra of the drosopterins are discussed on the basis of the proposed structure 1. The drosopterins show 4 pK‐values in the normal pH range and are relatively basic compounds as can be seen from electrofocussing and electrophoresis experiments. Solvatochromic effects are in agreement with the merocyanine character of the pigments. Polarographic studies revealed two twoelectron waves of reduction as expected from the structure.
Charge Transfer as a Molecular Probe in Systems of Biological Interest VI: Interactions between Lysozyme and the Methyl 2‐acetamido‐6‐O‐(N‐methyl‐isonicotinylium)‐2‐deoxy‐β‐D‐glucopyranoside Ion
Authors: Verhoeven Jan , Schwyzer Robert
Published: December 2004

The synthesis of methyl 2‐acetamido‐6‐O‐(N‐methyl‐isonicotinylium)‐2‐deoxy‐β‐D‐glucopyranoside ion (2; iodide and chloride) is reported. Association with hen‐egg‐white lyso zyme causes chemical shift changes for its acetamido and glycosidic methyl groups comparable to those observed for the monosaccharide lysozyme inhibitor methyl 2‐acetamido‐3‐deoxy‐β‐Dglucopyranoside. The binding modes of the two compounds to the enzyme in solution therefore appear to be analogous. Furthermore, a charge transfer interaction of the pyridinium: indole type is observed spectrophotometrically, indicating that the 2/lysozyme complex in solution is similar to that of the monosaccharide (and polysaccharide) inhibitor in crystals (proximity of the ligand O6 to the enzyme Trp62).