bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical Selectivities Disguised by Mass Diffusion I. A simple model of mixing‐disguised reactions in solution. 1st communication on the selectivity of chemical processes
Authors: Ott Roland J. , Rys Paul
Published: December 2004

The influence of mass diffusion on substrate and positional selectivities is discussed. A simple model is developed which allows a description and simulation of the coupling of the mass diffusion with the chemical reaction during the mixing process of two reactant solutions. For competitive, consecutive reactions and competitive, parallel reactions the general behaviour and the dependence of the product selectivity on diffusion effects is demonstrated.
An Anomalous Oxidation of β‐Pinene
Authors: Jefford Charles W. , Roussel Albert , Evans Samuel M.
Published: December 2004

The oxidation of β‐pinene with aqueous alkaline potassium periodate and catalytic amounts of potassium permanganate gave, in addition to the expected oxidation product nopinone, a β‐ketol. The structure of the latter was shown to be 1‐(2‐hydroxyisopropyl)bicyclo[3.1.0]hexan‐2‐one. The formation of this anomalous side‐product represents a new type of rearrangement of the pinane skeleton.
Contribution à la phytochimie du genre Gentiana, XIII. Etude des composés flavoniques et xanthoniques dans les feuilles de Gentiana campestris L. 2ème communication
Authors: Kaldas Maryse , Hostettmann Kurt , Jacot‐Guillarmod André
Published: December 2004

Phytochemistry of genus Gentiana XIII. Study of flavocic and xantonic compounds in the leaves of Gentiana campestris L. 2nd communication.

By means of column chromatography on polyamide, we have isolated from the leaves of Gentiana campestris L. a new xanthone‐O‐glucoside, the 3,4‐dimethoxy‐5, 8‐dihydroxy‐xanthone‐1‐O‐β‐D‐glucopyranoside (2) and its aglucone, the 3,4‐dimethoxy‐1,5,8‐trihydroxy‐xanthone (1). The C‐glucosides mangiferin (3) and swertisin (4) have also been isolated and identified.
Photochemie von 1,1‐Dimethyl‐4‐phenyl‐ und 1‐Methyl‐1‐phenyl‐1,2‐dihydronaphthalin; Nachweis einer photochemischen, sigmatropischen [1,7]H‐Verschiebung. 41. Mitteilung über Photoreaktionen
Authors: Widmer Ulrich , Heimgartner Heinz
Published: December 2004

Photochemistry of 1,1‐dimethyl‐4‐phenyl‐and 1‐Methyl‐1‐phenyl‐1,2‐dihydronaphthalene; evidence for a photochemical, sigmatropic [1,7]H‐shift.

Irradiation of 1,1‐dimethyl‐4‐phenyl‐1,2‐dihydronaphthalene (11) and 1‐methyl‐1‐phenyl‐1,2‐dihydronaphthalene (8) in pentane were investigated at −112° to −118°, using a mercury high pressure lamp. The [1,5]‐hydrogen‐shift products 13 and 17, respectively, the [1,7]‐hydrogen‐shift products 15 and 10, respectively and the photochemical Diels‐Alder products 14 and 18, respectively, were obtained, presumably via the ω‐vinyl‐o‐quinodimethane intermediates 12 and 9 (Schema 3).

Irradiation of the 1,2‐dihydronaphthalene 11 at −181° to −183° in a 2,2‐dimethylbutane/pentane matrix, gave rise to an UV.‐maximum at 402 nm which is assigned to the o‐quinodimethane derivative 12. After warming the solution around −130° or to room temperature, a product mixture was obtained, which mainly consist of the [1,7]‐hydrogen‐shift product 15 accompanied by the [1,5]‐hydrogen‐shift products 13 and 16 and the photochemical Diels‐Alder product 14 (Table 1). When the o‐quinodimethane intermediate 12 was irradiated with 406 nm‐light, the longwavelength absorption completely disappeared. This solution, after warmingup, yielded mainly the [1,5]‐hydrogen‐shift products 13 and 16 together with the bicyclic compound 14 and surprisingly a small amount of the [1,7]‐hydrogen‐shift product 15 (Table 1).

Similar experiments were carried out with the 1,2‐dihydronaphthalene 8. The results clearly indicate that irradiation of the o‐quinodimethane 9 at −180° to −185° with 406 nm‐light caused [1,5]‐ and [1,7]‐hydrogen shifts in a ratio of approximately 1:1 (Table 2).

From the experiments described above it follows, that the phenyl‐substituted α‐methyl‐ω‐vinyl‐o‐quinodimethanes 12 and 9 undergo upon irradiation with light of λ > 400 nm, besides photochemical Diels‐Alder reactions, also [1,5]‐ and [1,7]‐ hydrogen shifts.

It is remarkable that the thermal [1,7]‐hydrogen‐shifts of the o‐quinodimethanes 12 and 9 occur readily around −130°, whilst a temperature of −70° is needed to promote [1,7]‐hydrogen‐shifts in the non‐phenylated o‐quinodimethanes of the type 2 (Schema 1). The phenyl group in ω‐ or α‐position may enter into conjugation with the π‐system in the helcal transition state of the [1,7]‐hydrogen shift, but not in the reactants 12 and 9.
Carotenoid composition in Safran.
Authors: Pfander Hanspeter , Wittwer Fritz
Published: December 2004

In der vorliegenden Arbeit wurden aus dem Äthanolextrakt (70proz.) von Safran naturalis zwei weitere Crocetinderivate isoliert. Bei den beiden Verbindungen handelt es sich um Crocetin‐mono‐(β‐D‐gentiobiosyl)‐ester(VII) und Crocetin‐mono‐(β‐D‐glucosyl)‐ester(VIII). Die Charakterisierung erfolgte sowohl für die natürlich vorkommenden Zuckerester (VII, VIII), sowie für die entsprechenden Peracetylderivate (IX, X) mit Hilfe von UV./VIS.‐(VII, VIII, IX, X), IR,‐ (VII, IX), NMR.‐ (VII, IX, X) und Massenspektren (IX, X). Der Zuckernachweis erfolgte mittels Papier‐, Dünnschicht‐ und Gas‐Chromatographie.
Propellanes, XXXII. Preparation of Propellane Lactones by Means of the Chloronitrone Reaction
Authors: Rüttimann August , Ginsburg David
Published: December 2004

Two [4.4.3]propellane lactones 3 and 8 were prepared by employing the chloronitrone reaction. The intermediate propellanes 9 and 12 were also isolated in pure form.
Electrostatic Potential Field and Nucleophilicity of 3, 5, 8, 10‐Tetramethyl‐aceheptylene
Authors: Almlöf Jan , Haselbach Edwin , Jachimowicz Felicjan , Kowalewski Jozef
Published: December 2004

The electrostatic potential (EP.) for aceheptylene (I) is calculated using ab‐initio wavefunctions. In addition, the EP. around I is approximated by a monopole expression, using wavefunctions from various semiempirical procedures as a basis. It is found that the previously noted discrepancy between the thoretical prediction of differential nuclophilicity of the individual unsaturated C‐atoms in 3,5,8,10‐tetramethyl‐aceheptylene(II) and the experimental results of protonation is removed, if instead of local atomic charges, the EP. around II, approximated by that of I is considered.
Umcyclopropanisierung bei der Tetrabromierung eines tricyclischen Ketons zu 3exo, 4endo, 6exo‐Tribrom‐7‐brommethyl‐1,5‐dimethyl‐tricyclo[3.2.1.02,7]octan‐8‐on
Authors: Peter‐Katalinič Jasna , Zsindely Janos , Schmid Hans , Oberhänsli Willi E.
Published: December 2004

Transcyclopropanation during the Tetrabromination of a Tricyclic Ketone to 3 exo, 4 endo, 6exo‐Tribromo‐7‐bromomethyl‐1,5‐dimethyl‐tricyclo[3.2.1.02,7]octan‐8‐one

Bromination of the tricyclic ketone 1 with an excess of bromine at low temperature gives in approximately 30% yield the highly crystalline tricyclic tetrabromide 2 (Scheme 1). The structure of 2 was established by NMR.‐ and especially X‐ray‐analysis (Fig.1).

Treatment of 1 with 1 mol‐equ. of bromine gives an unstable dibromide, to which the structure 3 was assigned on the basis of its NMR.‐spectrum and its further bromination to 2 (Scheme 1). In the course of the tetrabromination of 1 the original cyclopropane ring is opened in the first step (1 → 3) and another cyclopropane ring is formed in the second step (3 → 2) (cf. Scheme 3).
Fluororganische Synthesen V Darstellung und Abwandlung von Chlorfluorcyclopropanen ‐ Ein gezielter Zugang zu Fluorallylalkoholen
Authors: Schlosser Manfred , Van Chau Le
Published: December 2004

Fluoroorganic Syntheses V. Preparation and Transformation of Chlorofluorocyclopropanes. – A Selective Approach to Fluoroallylic Alcohols

Chlorofluorocarbene addition to unsaturated compounds is particularly convenient and efficient in a two‐phase system. This method works satisfactorily even if the olefin carries base‐sensitive substituents. The resultant chlorofluorocyclopropanes can be ring‐opened by silver‐salt assisted acetolysis affording 2‐fluorallylacetates, which yield 2‐fluorallylic alcohols upon saponification.
Proof of the Existence of a Linear, Centrosymmetric Polyiodide Ion I: the crystal structure of Cu(NH3)4 I4
Authors: Dubler Erich , Linowsky Lothar
Published: December 2004

Tetrammine‐copper(II)‐tetraiodide Cu(NH3)4I4 crystallizes in the monoclinic space group C 2/m. The crystal structure has been determined from X‐ray diffractometer data and refined to Rw = 2.2%. Four coplanar nitrogen atoms and two axial iodine atoms form an octahedral coordination around Cu(II) with a pronounced 4 + 2 tetragonal distortion. A connection of the Cu(II) atoms by linear, centrosymmetric I polyiodide ions results in infinite chains of [Cu(NH3) I]‐units. The central I‐I‐bond distance in I is 2.802(1) Å; a considerable amount of I‐I bonding is indicated by the distance of 3.342(1) Å found for the terminal bonds. These intramolecular bond distances correspond to calculated I‐I‐bond orders of 0.80 and 0.43.
Ptérobiline et néoptérobilines, réactivité et structures
Authors: Choussy Michèle , Barbier Michel
Published: December 2004

Pterobiline and neopterobilines, reactivity and structures

Pterobiline (biliverdine IX γ) and the two neopterobilines: phorcabiline and sarpedobiline, are the three main bile pigments found in Lepidopters. Studies on the reactivity of pterobiline (1) and phorcabiline esters are reported. Preparation of derivatives, in vitro transformation of pterobiline into phorcabiline, analysis of the pigments and their derivatives by field desorption mass spectrometry and Fourier transform NMR., lead to the structure 5 for the dimethyl ester of phorcabiline. By a similar reaction, biliverdine IX δ (15) affords the neobiliverdine IX δ (16). Possibility of an easy formation of new tetrapyrrolic compounds in the IX γ and IX δ series is thus reported for the first time.
Photochemische Reaktionen. 83. Mitteilung. Verbindungen der 3,4‐Dihydrojonon‐Reihe als Modelle zur Photochemie γ, δ‐ bzw. δ, ϵ‐ungesättigter Ketone und Aldehyde
Authors: Zink Markus Peter , Wolf Hans Richard , Müller Ernst Peter , Schweizer Wolfhard Bernd , Jeger Oskar
Published: December 2004

Compounds of the 3,4‐dihydro‐ionone series as models for the photochemistry of γ, δ‐ and δ,ϵ‐ unsaturated ketones and aldehydes.

The photochemistry of γ, δ‐ and δ,ϵ‐unsaturated carbonyl compounds of the dihydro‐ionone series has been studied, with special attention to the investigation of oxetane formation versus hydrogen abstraction.

UV.‐irradiation of the dihydro‐β‐ionone compounds with structure A (1, 7, 14, 18, 24, 29) led to isomeric ethers with structures B (2, 8, 15, 19, 25, 30), C (3, 9, 16, 20, 26, 31) and D (4, 21, 27), isomeric bicyclic alcohols with structure E (5, 10, 17, 22, 28), and photoreduction products with structure F (6, 11, 12, 13). Photolysis of dihydro‐γ‐ionone (32) gave a complex mixture containing fragmentation product 35, hydrocarbon 36, β‐ambrinol (34), oxetane 33, as well as dihydro‐β‐ionone (1) and three of its photoproducts (2, 3, 5). The dihydro‐α‐ionone compounds 37 and 40 gave mixtures of fragmentation products and the oxetanes 38 and 41. Irradiation of the side‐chain homologues 42 and 45 yielded 43, which photo‐cyclizes to 44. In contrast, 3, 4‐dihydro‐3′,4′‐dehydro‐β‐ionone (46) gave merely the isomeric open‐chain triene‐ketone 47.

The structures assigned to the ethers 2, 3, 33, 38 and to the alcohols 5, 10, 13 could be confirmed by chemical reactions and mutual interconversions. The structure of the ether 21 had to be established by X‐ray analysis, details of which are described.

A novel intramolecular hydrogen transfer is involved in formation of ethers B. The photocyclization A → D probably proceeds by addition of the carbonyl‐C atom to the double bond (A → h), followed by methyl (1 → 2)‐shift (h → i). Process A → h may also be involved in formation of compounds of type C and E.
The Chemical Ionization of Organic Compounds. 2nd Communication. Linear Alkyl Halides
Authors: Houriet Raymond , Gäumann Tino
Published: December 2004

The chemical ionization spectra of linear alkyl halides with up to nine carbon atoms have been studied using water as protonating agent. An alkyl ion with the same number of carbon atoms as the halide is produced. With more than six carbon atoms in the chain, fragmentation becomes important. The results show that excited hydronium ions participate as intermediates and the fragments of the resulting alkyl ions have branched structures.
Ammoniakverlust aus α,ω‐Alkandiaminen im Massenspektrometer. 22. Mitteilung über das massenspektrometrische Verhalten von Stickstoffverbindungen
Authors: Mayerl Friedrich , Hesse Manfred
Published: December 2004

Loss of ammonia from α,ω‐alkanediamines in the mass spectrometer.

Under electron impact α,ω‐alkanediamines lose ammonia from the molecular ion. This fragmentation reaction is explained in the case of 1.4‐butanediamine (1) on the basis of the spectra of homologues and deuteriated derivatives. The reaction proceeds via neighbouring group participation; the mechanism is given in Scheme 1.
Azidiniumsalze. 16. Mitteilung [1]. Struktur‐Reaktivitätsbeziehungen in Serien quartärer N‐Heteroaromaten: Kinetik der Reaktion heterocyclischer Azidiniumsalze mit Sulfit‐Ionen
Authors: Hellrung Bruno , Balli Heinz
Published: December 2004

Structure‐Reactivity‐Relationships in Series of Quaternary Heterocyclic Compounds: Reaction Kinetics of Heterocyclic Azidinium Salts with Sulfite Ions.

Die Reaktion der Azidiniumsalze 1a–f mit Sulfit‐Ionen, die Isomerisierungs‐ und Zerfallsreaktion der entstandenen Sulfotriazene 4a–f und 5a–f wurden mittels kinetischer Methoden untersucht. Die Säuredissoziationskonstanten der Sulfotriazene 4a–f und 5a–f wurden bestimmt und die Geschwindigkeits‐ und Aciditätskonstanten mit σHet‐Werten korreliert.
Umwandlung des Tricyclo[5,4,0,03,9]undecadiengerüstes in das neue Octahydro‐2,5‐methano‐azulengerüst
Authors: Fráater György
Published: December 2004

Transformation of the Tricyclo[5,4,0,03,9]undecadiene System into the new Octahydro‐2,5‐methano‐azulene System.

1,3,6‐Trimethyl‐tricyclo[5.4.0.03,9]undeca‐5, 10‐dien‐2‐one (1) was successively treated with sodium amide in toluene, potassium hydroxide in water, LiAlH4 in ether and TsCl in pyridine to give the p‐toluenesulfonate 5 in 66% overall yield. The solvolysis of 5 resulted in the remarkably clean formation of 6, 8a‐dimethyl‐9‐methyl‐iden‐2,5‐methano‐1,2,3,3a,4,5,8,8a‐octahydroazulene (6). The carboxylic acid 3 upon treatment with thionylchlorid in benzene at 70° underwent a spontaneous intramolecular Friedel‐Crafts acylation to give 9 and 10 which have the same carbonskeleton as 6. The endo‐chloro configuration of 10 was demonstrated by reduction of 10 to 4; this reaction proceeds presumably through a reductive fragmentation, the stereoelectronic requirements of which are given in the endo‐isomer of 10 only.
Halogenierte Pyridine I. Die Herstellung von 3‐Halogenmethylpyridinen aus dimerem Acrylnitril
Authors: Fritz Hans , Weis Claus D. , Winkler Tammo
Published: December 2004

Halogenated pyridines I. The synthesis of 3‐halogenomethyl pyridines from dimeric acrylonitrile.

α‐Methyleneglutaronitril, a linear dimerization product of acrylonitrile is a cheap, commercially available starting material for a new synthesis of 3‐halogenomethyl‐2, 6‐dihalogeno‐ or 2,5,6‐trihalogenopyridines prepared in two and three step reactions, respectively. The properties of this new class of halogenated pyridines are discussed.
Über Pterinchemie. 55. Mitteilung [1]. Reindarstellung und Charakterisierung von 5,6,7,8‐Tetrahydro‐L‐neopterin und 5,6,7,8‐Tetrahydro‐D‐monapterin
Authors: Schircks Bernhard , Bieri Jost H. , Viscontini Max
Published: December 2004

Preparation and characterisation of pure 5,6,7,8‐tetrahydro‐L‐neopterine und 5,6,7,8‐tetrahydro‐D‐monapterine.

The synthesis of these two compounds, III and IV, is described, and their structures ascertained by means of 1H‐NMR., 13C‐NMR. and FD. spectroscopy. In particular the possibility of detecting diastereomeric pairs of types III and IV in 13C‐NMR. spectra is discussed.
Tetrazoloazines. 15N nuclear magnetic resonance and infrared absorption spectroscopy
Authors: Thétaz Célestin , Wehrli F. W. , Wentrup Curt
Published: December 2004

The reaction of 4‐chloro‐2‐phenylquinazoline with K15NN2 has been studied by 15N‐NMR. spectroscopy. 15N‐chemical shifts in 5‐phenyl‐1 (3)‐[15N]‐tetrazolo[1,5‐c]quinazoline and ‐Nα(Nγ)‐[15N]‐4‐azido‐2‐phenylquinazoline are reported. The characteristic IR. absorption frequencies of the tetrazole group have been determined in a series of annelated 15N‐labelled compounds. From these studies and the chemistry of the labelled tetrazoles, it is concluded that all haloazines examined react with KN3 by the direct nucleophilic substitution mechanism. An addition of nucleophile‐ring opening‐ring closure (ANRORC) mechanism was not observed. The synthesis of several 15N‐labelled tetrazoloazines is described.
Ein Tricarbonyleisen‐π‐Komplex mit einem Silacyclohexadienyl‐Liganden
Authors: Fink Walter
Published: December 2004

A Tricarbonyl Iron‐π‐Complex with a Silacyclohexadienyl‐Ligand.

The triphenylmethyl cation abstracts a hydride ion from 1,1‐dimethyl‐1‐silacyclohexa‐2,4‐diene‐tricarbonyl iron to give the 1,1‐dimethyl‐1‐silacyclohexadienyl‐tricarbonyl iron cation.
Electronic Structure, Molecular Conformation and Reactivity of Benzonorbornadiene Systems
Authors: Haselbach Edwin , Rossi Michel
Published: December 2004

From the photoelectron spectra of benzonorbornadiene (1) and its 9‐isopropylidene derivative (2) the energy and an approximate wave function for the highest occupied orbitals is obtained. With these results the differential reactivity of the systems in Diels‐Alder additions with ‘inverse electron demand’ is discussed on the basis of frontier orbitals. For the ground state of 2 similar non‐bonded interactions between the isopropylidene unit and the double bond or the benzene ring are indicated. Conformational equilibria in 9‐aza derivatives of 1 are discussed in view of these findings.
15N‐NMR. A Method for Assigning Structure in Complexes of Unsymmetrical o, o′–Dihydroxydiarylazo–Ligands
Authors: Pregosin Paul S. , Steiner Eginhard
Published: December 2004

The 15N‐NMR. parameters of some Pt(II)complexes of unsymmetrical o, o′‐dihydroxydiarylazo‐ligands are shown to be useful in the solution of subtle structural problems.
Nachweis von Fragment‐Genesen im Massenspektrometer. 3. Mitteilung. Aminosäuresequenz‐Analyse in Oligopeptiden und Oligopeptid‐Gemischen mit Hilfe der DADI‐Massenspektrometrie
Authors: Schlunegger Urs Peter , Hirter Peter , von Felten Hans
Published: December 2004

Detection of Fragment Genesis in the Mass Spectrometer. III. Analysis of Amino‐Acid Sequence in Oligopeptides and in Mixtures of Oligopeptides by DADI‐Mass Spectrometry.

The amino acid sequence was analysed by DADI mass spectrometry in simple oligopeptides and in mixtures containing two or three peptides.
Selektive Synthesen mit Organometallen V: Trimethylsilylmethyl‐kalium und andere Spitzenkönner unter den Metallierungsmitteln
Authors: Hartmann Jürgen , Schlosser Manfred
Published: December 2004

Trimethylsilylmethylpotassium and other outstanding metallating agents.

For the metallation of allylic and benzylic positions, trimethylsilylmethylpotassium is the most powerful reagent. Butyllithium in the presence of potassium t‐butoxide however, can usually replace it. Olefinic and cyclopropane hydrogen atoms are most readily attacked by pentylsodium, especially if the reaction is carried out in presence of potassium t‐butoxide. Trimethylsilylmethylpotassium, however, will equally work if an activating group, such as methoxy, is present in the substrate. Generalisations concerning the metallation mechanisms are drawn.
A Stereospecific Synthesis of Vitamin A from 2,2,6‐Trimethyl‐cyclohexanone
Authors: Olson Gary L. , Cheung H.‐C. , Morgan Keith D. , Borer René , Saucy Gabriel
Published: December 2004

An efficient synthesis of all‐(E) vitamin A acetate from 2,2,6‐trimethyl‐cyclohexanone has been achieved via the intermediacy of 1‐(9‐acetoxy‐3, 7‐dimethyl‐nona‐3,5,7‐trien‐1‐ynyl)‐2,2,6‐trimethyl‐cyclohexanol (25), readily prepared in high yield by allylic rearrangement of tertiary propenols with glacial acetic acid. The key step in the synthesis is the transformation of 25 to the unsaturated ketone 27 (9‐acetoxy‐3,7‐dimethyl‐1‐(2,6,6‐trimethyl‐cyclohex‐1‐enyl)‐nona‐3,5,7‐trien‐ 2‐one) using a novel vanadium(V)‐catalysed rearrangement reaction. The carbonyl in 27 affords the means for the essential isomerization of the adjacent double bond to the (E) isomer and the product is readily transformed into the polyene by reduction and elimination. An overall yield of 18–31% of vitamin A acetate from 2,2,6‐trimethyl‐cyclohexanone has been realized.
Synthesis and Some Reactions of 2,4,6‐Cycloheptatrienethione
Authors: Dugger Harry A. , Dreiding André S.
Published: December 2004

The synthesis of 2,4,6‐cycloheptatrienethione (1) was accomplished by reaction of tropone and phosphorus pentasulfide. Although 1 proved to be extremely unstable in concentrated solution, its UV. spectrum was measured, the ε‐values being determined indirectly by hydrolysis to tropone. The proof of structure rests on analytical data, conversion to tropone oxime on reaction with hydroxylamine and reaction with the sodium salt of malonitrile to give 2‐amino‐3‐cyano‐3aH‐cyclohepta[b]thiophene (4) which rearranged on chromatography to give what is probably the corresponding 8H‐compound (5). On dissolving 1 in 95% sulfuric acid, a large hypsochromic shift in the UV. spectrum was observed, which may be due to the mercaptotropylium ion.
Rastronole A, B, C, D, E, F, G und H; eine Gruppe multioxygenierter Diterpenbitterstoffe der ent‐Kauran‐Reihe aus Englerastrum scandens ALSTON
Authors: Nomoto Kyosuke , Rüedi Peter , Hans Eugster Conrad
Published: December 2004

Rastronols A, B, C, D, E, F, G, and H, a group of multioxygenated bitter principles with ent‐kaur‐16‐en‐15‐one structure from Englerastrum scandens ALSTON (Labiatae)

We have isolated from the leaves of Englerastrum scandens from Kenya eight new, highly oxygenated ent‐kaur‐16‐en‐15‐ones named rastronol A, B, C, D, E, F, G, and H, and determined their structures mainly by spectroscopic techniques as 1, 8, 14, 17, 20, 29, 39, and 51 respectively.
Preparation of cyano‐substituted styryl and stilbenyl compounds
Authors: Coviello Vincenzo , Emil Siegrist Adolf
Published: December 2004

o‐ und p‐Cyansubstituierte Toluol‐Derivate können mit Anilen aromatischer carbocyclischer oder heterocyclischer Aldehyde in Gegenwart von Dimethylformamid und Natriummethylat bei Raumtemperatur in die entsprechenden Styryl‐ bzw. Stillbenyl‐Verbindungen übergeführt werden (« Anil‐Synthese »). Zur Darstellung Cyan‐substituierter Bis‐styryl‐Verbindungen sind Schiffsche Basen aus aromatischen Dialdehyden und o‐Chloranilin ihrer guten Löslichkeit wegen besonders geeignet.
Photochemische Reaktionen. 89. Mitteilung [1]. Zur Photochemie konjugierter Epoxy‐diene I. Versuche mit (E),β‐Jonyliden‐epoxiden
Authors: Peter Alder Alex , Richard Wolf Hans , Jeger Oskar
Published: December 2004

Photolysis of conjugated epoxy‐dienes

UV.‐irradiation (λ = 254 nm) of (E),β‐ionylidene‐epoxide (3) in n‐pentane gives the isomeric cyclopropene‐ketone 7 (90%) in a hitherto unreported type of photoreaction. The methylsubstituted (E),β‐ionylidene‐epoxide 6, however, undergoes (E/Z)‐photoisomerization to the (Z),β‐ionylidene‐epoxide 8 (91%).
Cytochalasin B (Phomin): Abbaureaktionen und Cyclisierung der B‐Cytochalasinsäure zu 21,22‐Dihydro‐isocytochalasin A
Authors: Scherling Dietrich , Csendes Ivan , Tamm Christoph
Published: December 2004

Cytochalasin B (Phomin): Degradation Reactions and Cyclization of B‐Cytochalasinic Acid to 21,22‐Dihydro‐Isocytochalasin A

Treatment of the γ‐lacton 5, a transformation product of cytochalasin B (phomin) (1), with OsO4 gave the dihydroxy derivatives 6 and 7. Cleavage of the former by NaIO4 in aqueous methanol yielded a mixture of the dimethylacetal 10 and the unsaturated aldehyde 11, which are potential intermediates for a total synthesis of cytochalasins. Cytochalasin B (1) was hydrolysed with NaOH in aqueous dioxane to B‐cytochalasinic acid (14). Recyclization of 14 using the Mukaiyama‐Corey method [19] [20] did not yield cytochalasin B (1) but the isomeric 21,22‐dihydro‐isocytochalasin A (18). Treatment of 14 according to Gerlach [21] yielded the phthalimidine 19.
Versuche zur Redox‐Simulation der photochemischen A/D‐Secocorrin → Corrin‐Cycloisomerisierung. Elektrochemische Oxydation von Nickel(II)‐1‐methyliden‐2,2,7,7,12,12‐hexamethyl‐15‐cyan‐1,19‐secocorinat‐perchlorat. Vorläufige Mitteilung
Authors: Kräutler Bernhard , Pfaltz Andreas , Nordmann René , Hodgson Keith O. , Dunitz Jack D. , Eschenmoser Albert
Published: December 2004

Experiments on a simulation of the photochemical A/D‐secocorrin → corrin cycloisomerization by redox processes. Electrochemical oxidation of nickel(II)‐1‐methylidene‐2,2,7,7,12,12‐hexamethyl‐15‐cyano‐1,19‐secocorrinate perchlorate

Can the act of light excitation in the photochemical A/D‐secocorrin → corrin cycloisomerization be replaced by redox reactions in the dark? Electrochemical oxidation of nickel(II)‐A/D‐secocorrinate 4 in acetonitrile containing a trace of water produces the secocorrinoxide–nickel‐complex 5 (structure determined by X‐ray analysis) in almost quantitative yield. This two‐electron oxidation involves a hydrogen shift from the methylene group C(19) in ring D to the methylidene carbon atom at ring A in the radical cation intermediate. Since the same type of hydrogen shift occurs in the photochemical A/D‐secocorrin → corrin cycloisomerization, a close parallelism in their chemical reactivity seems to exist between electronically excited A/D‐secocorrins and corresponding radical cations. Formation of the corrin complex 2 (M = Ni+) could be achieved (so far only in modest yields) by electrochemical one‐electron oxidation of 4 in acetonitrile/acetanhydride/acetic acid 8:1:1 followed by one‐electron reduction. – The transformation of the oxide nickel complex 5 to the corrinoid complex 10 – a new member in the family of dehydrocorrins – is also recorded.
Abbaureaktionen an 3‐[2′‐(2″‐Dimethylaminoäthyl)‐phenyl]‐isochromanen
Authors: Wiegrebe Wolfgang , Michael Stephan Hans , Fricke Johann , Peter Schlunegger Urs
Published: December 2004

Degradation of 3‐[2′‐(2′‐Dimethylaminoethyl)‐phenyl]‐isochromanes

Degradation of the β‐dimethylaminoethyl sidechain of properly substituted 3‐aryl‐isochromanes produce inter alia the amines 2, the syrenes 3, the aldehyde 5b and the carboxylic acid 4b. The racemates of the amine 15 and the aldehyd 5b were resolved; the chiral center of the menthoxycarbonyl‐hydrazone was eliminated by ester interchange.
Synthèses de produits organofluorés VI Solvolyse de chlorofluorocyclopropanes
Authors: Bessière Yvonne , Schlosser Manfred
Published: December 2004

Fluoro‐organic Syntheses VI: The Solvolysis of Chlorofluoro‐cyclopropanes

2‐Fluoro‐allylic carbocations, generated from 1‐chloro‐1‐fluoro‐cyclopropanes or 2‐fluoro‐allyl p‐toluene‐sulfonates in water or acetic acid, undergo either proton loss or addition of hydroxyl or acetoxyl. In the latter case, an alkyl‐substituted 2‐fluoro‐allyl ion leads predominantly to the more branched product (e.g. 3‐fluoro‐2‐methyl‐3‐buten‐2‐ol) which may be converted into the less branched one (e.g. 2‐fluoro‐3‐methyl‐2‐buten‐2‐ol) through reversible reactions.
The Crystal Structure of (2 R, 7 S, 10 R)‐2,10‐diamino‐5,5,7‐trimethyl‐4,8‐diazaundecanenickel (II) perchlorate
Authors: Stoeckli‐Evans Helen
Published: December 2004

The structure of the title compound, a tricyclic Ni(II) tetra‐amine complex has been determined from analysis of photographic X‐ray data. The crystal system is orthorhombic, space group P212121, with unit cell dimensions a = 9.802, b = 8.998, c = 24.378 Å. The Ni atom is square planar coordinated. The six‐membered chelate ring has a chair conformation. One of the five‐membered chelate rings has a distorted gauche (λ) conformation with the methyl substituent in an equatorial position, the other has an unsymmetrical gauche (δ) conformation with the methyl substituent axial.
Mass Spectrometric Decomposition Processes in Labelled 1‐Heptenes
Authors: Falick Arnold M. , Gäumann Tino
Published: December 2004

The 70 eV mass spectra of a number of 13C‐ and D‐labelled analogs of 1‐heptene have been measured, as well as the metastable transitions in the non‐labelled compound. Isotopic distributions in the major fragment ions have been calculated from the high and low resolution data. The results show that considerable skeletal rearrangement must take place before formation of most of the fragment ions. Loss of methyl and ethyl radicals occurs mainly from the two ends of the molecule. Ethylene fragments come primarily from the unsaturated end of the molecule, but show evidence of significant prior skeletal rearrangement. The predicted McLafferty rearrangement accounts for only 2/3 of the C4H8+ ions formed, less for the C3H6+ ions. At least 80% of C4H9+ ions appear to be formed by allylic cleavage, as expected, but this mechanism can only account for a maximum of 20% of the formation of the complementary ion C3H5+. Both, this latter ion and C3H6+, are probably generated by loss of hydrogen from C3H7+.

Figures obtained for label retention in 1‐[13C]‐ and 1‐D‐labelled analogs were nearly identical for most fragment ions, probably indicating that the hydrogen atoms in position 1 remain on C(1) even following skeletal rearrangement. A similar result was found for the 7‐[13C]‐ and 7‐D‐labelled compounds. The main exceptions in the case of the products labelled in position 1 (C4H7+, C3H3+) seem to be due to initial loss of an hydrogen atom from this position followed by further fragmentation.
Photoinduzierte Cycloadditionen von 2,2‐Dimethyl‐3‐phenyl‐2H‐azirin an Nitrile und «push‐pull»‐Olefine. 43. Mitteilung über Photoreaktionen
Authors: Stegmann Werner , Gilgen Paul , Heimgartner Heinz , Schmid Hans
Published: December 2004

Photoinduced Cycloadditions of 2,2‐Dimethyl‐3‐phenyl‐2H‐azirine with Nitriles and ‘push‐pull’ Olefines.

Electron deficient nitriles of the type 5a–e in contrast to nonactivated nitriles undergo regiospecific [2+3]cycloadditions to benzonitrile isopropylide (2b), which was generated in situ by irradiation of 2,2‐dimethyl‐3‐phenyl‐2H‐azirine (1b), to yield the 2H‐imidazole derivatives 6a–e (Scheme 2). The structure of the photoproducts was mainly deduced from 13C‐NMR. and mass spectrometry.

Whereas normal olefins or enolethers do not react with 2b, push‐pull olefins of the type 10a–d readily undergo the cycloaddition to give the 3‐alkoxy‐5,5‐dimethyl‐2‐phenyl‐1‐pyrrolines 11a–d (Scheme 3 and 4). The structure of the photoproducts 11a–d indicates that the regiospecificity of the cycloaddition corresponds to that of acrylonitriles and acrylesters with 2b.
Enthalpy and Entropy of Formation of Alkali and Alkaline‐Earth Macrobicyclic Cryptate Complexes [1]
Authors: Kauffmann Elisabeth , Lehn Jean‐Marie , Sauvage Jean‐Pierre
Published: December 2004

The enthalpies and entropies of complexation of alkali and alkaline‐earth metal cations by several macrobicyclic ligands have been obtained from calorimetric measurements and from the previously determined stability constants [2]. Both enthalpy and entropy changes play an important role in the stability and selectivity of the complexes. Particularly noteworthy are the large enthalpies and the negative entropies of complexation obtained for the alkali cation complexes (Na+, K+, Rb+ and Cs+ cryptates). The Sr2+ and Ba2+ as well as [Li+ ⊂ 2.1.1]

For use of the symbols see [2].

and [Na+ ⊂ 2.2.1] cryptates are of the enthalpy dominant type with also a favourable entropy change. The Ca2+ and [Li+ ⊂ 2.2.1] cryptates are entirely entropy stabilized with about zero heat of reaction. The high stability of the macrobicyclic complexes as compared to the macromonocylcic ones, the cryptate effect, is of enthalpic origin. The enthalpies of complexation display selectivity peaks, as do the stabilities, whereas the entropy changes do not. The high M2+/M+ selectivities found in terms of free energy, may be reversed when enthalpy is considered in view of the very different role played by the entropy term for M2+ and M+ cations. The enthalpies and entropies of ligation show that whereas the cryptate anions are similar in terms of entropy irrespective of which cation is included, the ligands, despite being more rigid than the hydration shell, are nevertheless able to adjust to some extent to the cation. This conclusion agrees with published X‐rays data. The origin of the enthalpies and entropies of complexation is discussed in terms of structural features of the ligands and of solvation effects.
Molecular Orbital Studies of the Protonation of Diazomethane
Authors: Niemeyer Hermann M.
Published: December 2004

CNDO/Z, MINDO/3 and ab initio molecular orbital calculations indicate that C‐protonated diazomethane is more stable than N(end)‐protonated diazomethane. Extrapolation of these results to solution chemistry as well as the kinetic references of protonation of diazomethane are discussed.
Kalorimetrische Untersuchungen des Wassereinflusses auf den Lösungsvorgang von Aerosol OT in apolaren Lösungsmitteln
Authors: Christen Heinz , Eicke Hans‐Friedrich , Hammerich Holger , Strahm Ulrich
Published: December 2004

Calorimetric Investigations of the Effect of Water on the Solution Process of Aerosol OT in Apolar Media.

Heats of solution of Aerosol OT in apolar solvents are influenced considerably by already small amounts of water. Calorimetric investigations of the solution process with differently dried surfactant and solvent samples showed the predominating effect on the heats of hydration with regard to the ionic and polar groups of the surfactant. Only if the hydration is finished prior to the process of solution, the latter is endothermic.

An estimation of the various enthalpic contributions demonstrates that the destruction of the coherence of the built‐in water within the surfactant is decisive in the latter case. Two models corresponding to definite structures of the liquid crystalline mesophase of the surfactant show very satisfactory agreement with the experimental ΔH‐values.
Addition du chlorure de nitrosyle et de l'oxyde d'azote(III) sur l'allyltriméthylsilane et sur l'allylbenzyldiméthylsilane
Authors: Jolibois Henri , Doucet André , Perrot Roger
Published: December 2004

Additions of Nitrosyl chloride and Dinitrogen trioxide to Allyltrimethylsilane and Allylbenzyldlmethylsilane.

The reaction of nitrosyle chloride and dinitrogen trioxide with allyltrimethylsilane and allylbenzyldimethylsilane leads to nitrosochlorides and to pseudonitrosites. The structures of these compounds are proved by reduction to amines.
Zur Frage der Ladungsverteilung in ionischen π‐Systemen
Authors: Müllen Klaus
Published: December 2004

On the Charge Distribution in Ionic π‐Systems

The charge distribution in the anthracene dianion and dication is investigated by means of 13C‐NMR. spectroscopy and compared with the spin density distribution in the corresponding radical ions. It appears that the excess charge in the dianion is distributed in a highly non‐uniform manner and that, quite surprisingly, the quaternary carbon atoms bear positive charges. These findings can be rationalized by means of MO‐models.
The Structure of the Ion Pairs Formed by the Radical Anion of [2.2] Paracyclophane and the Potassium Cation
Authors: Gerson Fabian , Martin William B. , Wydler Christoph
Published: December 2004

The structure of the title ion pairs has been established by ESR. studies of the radical anion produced from 1,1,10,10,12,13,15,16‐octadeuterio[2.2]paracyclophane with potassium in tetrahydrofuran and 2‐methyltetrahydrofuran. The counter‐ion K⊕, which for steric reasons is forced to reside outside the framework of [2.2]paracyclophane, assumes a position above the centre of one benzene ring. Experimental support has been also obtained for the assignment of the coupling constants to those ring and methylene protons which are rendered non‐equivalent by the ion pairing.
Mycelprodukte höherer Pilze. 1. Mitteilung. Phenoxazin‐Derivate in Calocybe gambosa
Authors: Schlunegger Urs Peter , Kuchen Arnold , Clémençon Heinz
Published: December 2004

Mycelium Products in Higher Fungi. I. Phenoxazine Derivatives in Calocybe gambosa.

Phenoxazone and α‐Amino‐phenoxazone have been detected in cultured mycelium of Calocybe gambosa (FR.) DONK.
Crystal and Molecular Structure of 7‐(4‐chloro‐phenyl)‐8‐phenyl‐2,3‐dihydro‐imidazo[1,2‐a]pyrimidin‐5(8H)‐on
Authors: Weber Hans Peter , Petcher Trevor J.
Published: December 2004

Bei der Kondensation von 4‐Chlorphenyl‐propiolsäuremethylester mit 2‐Anilino‐2‐imidazol entsteht die Titelverbindung, deren Struktur durch eine Röntgenstrukturanalyse bewiesen wurde. Die Kristalle gehören in die azentrische, orthorhombische Raumgruppe Pna21, a = 13,49, b = 10,52 und c = 11,36 Å, mit Z = 4 Molekeln pro Zelle. Die Struktur wurde nach der Schweratommethode gelöst und bis R = 0,052 verfeinert.
A 13C‐ and 15N‐NMR. Study of Some 1‐Aryl‐3, 3‐dimethyl Triazene Derivatives
Authors: Axenrod Theodore , Mangiaracina Pietro , Pregosin Paul S.
Published: December 2004

13C‐ and 15N‐NMR. spectra have been measured for a series of triazenes. The results are compatible with the significant contribution of a structure such as II. One‐bond nitrogen‐nitrogen coupling constants are reported.
Microbial Transformation of (−)‐Δ1‐3,4‐trans‐Tetrahydrocannabinol by Cunninghamella blakesleeana LENDER
Authors: Binder Michael
Published: December 2004

Incubation of (−)‐Δ1‐3, 4‐trans‐tetrahydrocannabinol (= Δ1‐THC; 3) with stationary cultures of Cunninghamella blakesleeana LENDER (Zygomycetales) (ATCC 8688a) yielded a number of metabolic conversion products. Isolation and structure elucidation of 6α‐hydroxy‐Δ1‐THC (4), the potential psychoactive 3″‐hydroxy‐Δ1‐THC (2) and 4″‐hydroxy‐Δ1‐THC (1), and the hitherto unknown metabolites 4″‐hydroxy‐6‐oxo‐Δ1‐THC (5), 4″, 6α‐dihydroxy‐Δ1‐THC (7) and 4″, 7‐dihydroxy‐Δ1‐THC (6) is described.
Etude dans la série des radicaux hétérocycliques: partie XIV. Radicaux diméthyl‐3, 4‐isoxazolyl‐5. Réactivité en série aromatique et hétéroaromatique: nouvelle voie d'accès à des diméthyl‐3, 4‐isoxazoles subsitués en C(5) par des groupements aryle et hétéroaryle
Authors: Vernin Gaston , Siv Chhan , Treppendahl Svend , Metzger Jacques
Published: December 2004

The aprotic decomposition of 5‐amino‐3, 4‐dimethyl‐isoxazole with excess isoamyl nitrite in aromatic solvents (alkylbenzenes, polyalkylbenzenes, anisole etc.) and in heteroaromatic solvents (thiophene, 2, 4‐dimethylthiazole, pyridine, 4‐alkylpyridines, dimethyl‐ and trimethyl‐pyridines) leads to 5‐aryl‐ and 5‐heteroaryl‐isoxazoles in yields of about 40%. This method provides a new way of obtaining 5‐iodo‐3, 4‐dimethyl‐isoxazole by the aprotic decomposition of the corresponding amine in the presence of iodine (yield: 30%).

The relative reactivity of the 3,4‐dimethylisoxazol‐5‐yl radical in alkyl benzenes, in anisole and in alkylpyridines is very similar to that of other heteroaromatic radicals with the radical site next to a sulfur or an oxygen atom. The radical shows electrophilic character because of the inductive effect of the oxygen atom. In the pyridine series an abnormally high percentage of 2‐substitution occurs. This may be explained by a solvatation effect. The characteristic GLC., NMR. and MS. data are reported for most of the compounds studied.
2‐ und 6‐Methyl‐8‐oxa‐bicyclo[5.1.0]octa‐2,4‐dien. Über den Verlauf der Ringöffnung bei der Thermolyse in der Gasphase
Authors: Schiess Peter , Fünfschilling Peter
Published: December 2004

2‐ and 6‐Methyl‐8‐oxabicyclo[5.1.0]octa‐2,4‐diene. Ring cleavage reaction upon flash pyrolysis.

6‐Methyl‐8‐oxa‐bicyclo[5.1.0]‐octa‐2,4‐diene (1 a) has been subjected to flash pyrolysis with the aim to elucidate the course of its thermal ring cleavage reaction. At 100° equilibrium between 1a (6%) and its 2‐methylisomer 1 b (94%) is reached through a remarkably facile [1,5]‐hydrogen shift. Above 200° methyl‐bicyclo[3.2.0]hept‐2‐ene‐7‐ones (3), dihydrotolualdehydes 5 and 6 and their aromatization products 7 are isolated. It is concluded that these products arise from 2‐, 3‐ and 7‐methyl‐hepta‐2,4,6‐trienal 2a, 2b and 2f which are formed from 1a/1b by path C and D in Scheme 2 involving a formal [2+6]‐cycloreversion reaction of 1a/1b and of its valence isomer, 1,2‐homooxepine 11. Two alternate pathways, A and B, involving cleavage of the C,C bond common to both rings in 1 concomitant or followed by hydrogen shifts are not operative.
Umwandlung von 6‐Methyliden‐tricyclo[3.2.1.02,7]oct‐3‐en‐8‐onen in Norcaradien/Cycloheptatrien‐Derivate
Authors: Mukherjee‐Müller Gabriele , Winkler Tammo , Zsindely Janos , Schmid Hans
Published: December 2004

Transformation of 6‐Methyliden‐tricyclo[3.2.1.02,7]oct‐3‐en‐8‐ones into Norcaradiene/Cycloheptatriene‐Derivatives.

Tricyclic ketones of type 1,5‐dimethyl‐6‐methyliden‐tricyclo[3.2.1.02,7]oct‐3‐en‐8‐one (1) [1] rearrange on heating with sodium methylate mainly to methyl‐7‐methyl‐bicyclo[4.1.0]hepta‐2,4‐dien‐7‐carboxylates = methyl‐7‐methyl‐norcaradien‐7‐carboxylates (4). Moreover, the formation of methyl 2‐aryl‐propionate (5) is observed. Thus, tricyclic 1 gives a mixture of norcaradiene derivatives 2 and 4 in 50% yield together with 13% of methyl 2‐(2′, 3′‐dimethylphenyl)‐propionate (5) (Scheme 1). Similarly the tricyclic ketone 7 rearranges to norcaradienes 8 and 9 (31,5%) and methyl 2‐(2′, 3′, 5′‐trimethylphenyl)‐propionate (10, 4%). In this case, the reduction products of 7, i.e. the alcohols 11 (24%) and 12 (8%) as well as other products derived from 11 are observed; heating of the endo‐alcohol 11 with sodium methylate leads to the 2‐arylpropan‐1‐ols 13 and 14 (Scheme 2). Under the same conditions the ketone 18 affords the norcaradiene ester 20 (Scheme 3). Scheme 4 shows the rearrangement of the pentacyclic ketone 21 to the cycloheptatriene derivative 22 and the base catalysed isomerisation of 22 to 23.

The structure elucidations were achieved with the help of UV.‐, IR.‐ and mainly NMR. spectra. The carboxy or methoxycarbonyl group assumes the exo‐position in all the norcaradiene derivatives (NMR., also in the presence of NMR. shift reagents). The cycloheptatriene‐noncaradiene‐equilibrium is shifted to the norcaradiene side to > 95% in compounds 2, 4, 8 and 9 and to > 90% in 19 and 20. This is due to the 7‐exo‐carboxy or 7‐exo‐methoxycarbonyl group and the methyl groups in positions 2 and 3 (cf. Klärner [9], chapter 4). On the other hand, in the case of 22 the cycloheptatriene structure is almost exclusively predominant.

The most probable mechanism for the rearrangement of tricyclic ketones of type 1 to methylnorcaradien‐7‐exo‐carboxylates or to the corresponding carboxylic acids is depicted in Scheme 5. Thus, the reaction path leads from 1 through a, c, f, g and h to 4. The aromatization reaction of 1 to 5 and 3 proceeds preferentially through a, c (Scheme 5) and k (Scheme 6). The conversation of the tricyclic endo‐alcohol 11 to 2‐aryl‐propan‐1‐ols 13 and 14 using sodium methylate occurs to ca. 90% via m → n and ca. 10% via m → p (Scheme 7); the primarily formed 2‐aryl‐propanals are reduced under the reaction conditions. The exo‐isomer 12 shows no similar reaction.
Facteurs stériques influençant la transposition de Wagner‐Meerwein des carbocations de type pinanyle
Authors: Barthélémy Michel , Gianfermi Anne , Bessière Yvonne
Published: December 2004

Steric factors influencing Wagner‐Meerwein rearrangement of pinanyl carboniumions.

The course of the Wagner‐Meerwein rearrangement of ions obtained by protonation of substituted α‐ or β‐pinenes is strongly dependent on the configuration of the substituents. The situation is complicated by the possibility of double bond isomerisation (α‐→β‐pinenes) before rearrangement. Simple rules for predicting the products are given.
Physico‐chemical properties of deuteriated compounds 3rd communication. The viscosity of n‐heptane
Authors: Öz Hami , Gäumann Tino
Published: December 2004

The kinematic viscosity of mixtures of perdeuteriated and protiated heptane has been measured between 15° and 35° and is given in polynomial form as a function of concentration and temperature. Using the McAllister equation to describe viscosity [4], it can be shown that the interactions between molecules containing the same or different isotopic species differ slightly.
A Chemical Study of Virginia Tobacco Flavour (Nicotiana Tabacum L.). I. Isolation and Synthesis of Two Bicyclodamascenones
Authors: Demole Edouard , Enggist Paul
Published: December 2004

Aged Virginia tobacco was steam‐distilled and the resulting condensate investigated by chromatographic methods. This allowed identification of the bicyclodamascenones A and B in a small subfraction from this condensate. Both these ketones, which are novel tobacco constituents, were also synthesized and a possible mechanism is proposed for their formation via acid‐catalysed cyclization of β‐damascenone (1).
Die Synthese von 1,3‐disubstituierten Adamantanen
Authors: Fischer Walter , Grob Cyril A. , Katayama Hajime
Published: December 2004

Synthesis of 1,3‐Disubstituted Adamantanes.

A series of new 1‐substituted 3‐bromoadamantanes has been prepared. An improved method for the formation of cyclopropanes from olefins with diazomethane and copper salts is described.
Isolation and Structure of Eucosterol and 16 β‐Hydroxyeucosterol, Two Novel Spirocyclic Nortriterpenes, and of a New 24‐ Nor‐5α‐chola‐8, 16‐diene‐23‐oic Acid from Bulbs of Several Eucomis Species
Authors: Ziegler René , Tamm Christoph
Published: December 2004

Eucosterol and 16 β‐hydroxy‐eucosterol which have been isolated from several Eucomis species have been shown to be (23S)‐17,23‐epoxy‐3β,31‐dihydroxy‐27‐nor‐5α‐lanost‐8‐ene‐15,24‐dione (1) and (23 S)‐17,23‐epoxy‐3β,16β,31‐trihydroxy‐27‐nor‐5α‐lanost‐8‐ene‐15,24‐dione (2) by chemical transformations and spectral data. The spiro‐fused furanoic ether linkage of both metabolites represents a novel structural element for natural nortriterpenes. The structure of another metabolite (16), 3β‐hydroxy‐4β‐hydroxymethyl‐4,14α‐dimethyl‐15‐oxo‐24‐nor‐5α‐chola‐8,16‐diene‐23‐oic acid, from Eucomis autumnalis (Mill.) Chitt. was elucidated by chemical correlation of its methyl ester 17 with a degradation product of eucosterol (1).
Über Reaktionen oxygenierter Kobalt(II)‐Chelate. VII. Zur Stabilität einfach und doppelt verbrückter μ‐Peroxo‐dikobalt(III)‐Komplexe
Authors: Braun‐Steinle Dorothee , Mäcke Helmut , Fallab Silvio
Published: December 2004

On reactions of oxygenated Cobalt(II) Chelates. VII. Stability of mono and doubly bridged μ‐Peroxo‐dicobalt(III) Complexes.

The oxygen carrier properties of the cobalt(II) chelates of symmetrical diethylenetriamine‐4‐acetic acid (dtma) and unsymmetrical ethylenediamine‐1,1‐diacetic acid (edda) have been investigated by O2 equilibrium measurements in alkaline solution. Maximum O2 uptake is at pH = pKH (4), indicating that μ‐peroxo‐μ‐hydroxodicobalt(III) ion is the only oxygenated species formed in aqueous solution. Relationships between stability and structural factors are discussed.
1‐Aralkylated Tetrahydro‐2‐benzazepines. Part III. Synthesis from β‐tetralones
Authors: Berney Daniel , Schuh Karlheinz
Published: December 2004

1‐Benzyl‐tetrahydro‐2‐benzazepin‐3‐ones 4 were prepared by submitting the corresponding 1‐benzyl‐β‐tetralones 3 to the Schmidt reaction. On the other hand, the rearrangement of the tetralones 3 by the Beckmann procedure gave 1‐benzyl‐tetrahydro‐3‐benzazepin‐2‐ones 5. The syntheses of some hexahydrophenanthro‐azepines of types 10 and 15 are also described.