bluuebunny/crossref_metadata_2025 huggingface dataset:
Azidiniumsalze. 10.Mitteilung [1]. Struktur‐Reaktivitäts‐Beziehungen in Serien quartärer N‐Heteroaromaten: Diazogruppen‐Übertragungsreaktion heterocyclischer Azidiniumsalze auf 1‐(p‐Sulfophenyl)‐3‐methylpyrazolin‐5‐on und 1‐(m‐Sulfophenyl)‐3‐methyl‐5‐amino‐pyrazol
Authors: Balli Heinz , Hellrung Bruno , Kneubühler‐Hof Annemarie
Published: December 2004

Es wurde die Diazogruppen‐Übertragungsreaktion von Azidinumsalzen des Typs 1 auf 1‐(p‐Sulfophenyl)‐3‐methyl‐pyrazolin‐5‐on und 1‐(m‐Sulfophenyl)‐3‐methyl‐5‐amino‐pyrazol untersucht und die Geschwindigkeitskonstante der Reaktion in Abhängigkeit vom Heterocyclus des Azidiniumsalzes bestimmt. Die Geschwindigkeitskonstanten k1 zeigen untereinander und mit den aus den pK‐Werten der Iminoverbindungen 4 definierten σHet‐Werten [1] eine gute Korrelation in Form einer linearen Freien‐Energie‐Beziehung.
Synthesis of some Indanones having Nitrogen‐containing Substituents
Authors: Berney Daniel , Jauner Theodor
Published: December 2004

The title compounds have been synthesized by a Friedel‐Crafts acylation‐alkylation between aromatic ethers and α,β‐unsaturated carboxylic acids (or esters) having nitrogen‐containing substituents. Polyphosphoric acid was used as condensing agent.
Intramolekulare Diels‐Alder‐Additionen von 1,2‐Dihydropyridinen
Authors: Greuter Hans , Schmid Hans
Published: December 2004

Reduction of the pyridinium salts 1b‐f in methanolic sodium hydroxide solution with sodium borohydride gave the dimeric dihydropyridine derivatives 3b‐f. Heating these dimers in hydrocarbon solvents at 110–207° resulted in the formation of the tricyclic amines 4c–f, which were shown to be products of an intramolecular Diels‐Alder addition within the intermediate dihydropyridines 2c–f. The structures of 4c–f were deduced from spectroscopic, mainly NMR. data.
C(10)‐Methylation of Steroidal Synthesis Intermediate BCD‐Tricyclic 9‐En‐5‐ones
Authors: Scott John W. , Buchschacher Paul , Labler Ludwik , Meier Werner , Fürst Andor
Published: December 2004

A literature survey indicated that stereospecific non‐reductive β‐face methylation at C(10) of steroidal synthesis intermediate BCD‐tricyclic 9‐en‐5‐ones had never been effected. An attempt to define the factors controlling the β/α product ratio in such alkylations was made. The course of methylation is significantly affected by the temperature. In the best case, methylation of the sodium enolate of 17 β‐t‐butoxy‐19‐(3,5‐dimethyl‐4‐isoxazolyl)‐deA‐androst‐9‐en‐5‐one (18) in tetrahydrofuran at − 78° gave a β/α product ratio of > 5:1. The reaction mixture contained no unalkylated or dialkylated materials, indicating that enolate exchange probably did not occur at this temperature. The 10β‐methylated product 23, isolated in 78% yield, was converted to Δ9(ll)‐dehydrotestosterone (29). Compounds 23 and 29 are potential intermediates for the synthesis of 11‐oxygenated steroids.
Darstellung und Eigenschaften von Chromtricarbonyl‐Komplexen strukturisomerer Borazin‐Derivate
Authors: Scotti Mario , Werner Helmut
Published: December 2004

The new hexaalkylborazine chromium tricarbonyls (n‐Pr)3B3N3Me3Cr(CO)3 (V), Me3B3N3(n‐Pr)3Cr(CO)3 (VI), (i‐Pr)3B3N3Me3Cr(CO)3 (VII) and Me3B3N3(i‐Pr)3Cr(CO)3 (VIII) have been prepared from fac‐Cr(CO)3(MeCN)3 and the corresponding borazine in dioxane or without solvent. They are much more labile than the isomeric complex Et3B3N3Et3Cr(CO)3 (IV) which can be readily obtained from Et3B3N3Me3Cr(CO)3 and Et3B3N3Et3 by ring ligand exchange. The NMR., IR., UV. and Mass spectroscopic data of the complexes IV–VIII will be briefly discussed. The preparation of the borazine derivatives (n‐Pr)3B3N3Me3 (IX) and Me3B3N3(n‐Pr)3 (X) is also reported.
Identification d'un acide diterpenique du bourgeon de cassis
Authors: George Gérard , Candela Charles , Quinet Michel , Fellous Roland
Published: December 2004

The acidic fraction of benzenic extract of Blackberry bud (Ribes nigrum L.) show a diterpene acid identified as hardwickiic acid by IR., UV., RMN. and SM.
Über Reaktionen oxygenierter Kobalt(II)‐Chelate. II. Konfigurationsisomere Oxygenierungsprodukte von Tetraäthylenpentaminkobalt(II)
Authors: Zehnder Margareta , Fallab Silvio
Published: December 2004

On oxygenation of alcoholic solutions of tetraethylenepentamine cobalt(II) two isomeric forms of [(tetren)CoO2Co(tetren)]4+ are obtained in which the configuration of the pentadentate ligand is either α or β. The binuclear complex can be crystallized as thiocyanate or as perchlorate. Oxygenation at 35° produces the pure α isomer. At lower temperature a mixture of α and β is obtained. The isomers differ slightly in their absorption spectra and their reactivity. The ligand configuration has been elucidated by transforming the perchlorates into the [ZnCl4]2− salts of the corresponding mononuclear chelates [Co(tetren)Cl]2+. The latter have also been prepared starting from a compound of known configuration according to the literature. The IR. spectra of the α and β forms differ characteristically in the NH stretch bands.
Substituent Increments for the 1H‐NMR. Chemical Shifts of the 18‐ and 19‐Methyl Protons of Steroids. Part II: 9α,10β(normal)‐steroids
Authors: Arnold Wolf , Meister Walter , Englert Gerhard
Published: December 2004

In Part II of this series we report 292 substituent increments for the 1H‐NMR. chemical shifts (solvent: CDCl3) of the 18‐ and 19‐methyl protons of 9α,10β(normal)‐steroids relative to 5α,9α,10β,‐androstane. The increments were calculated by a least‐squares procedure from 988 spectra of 681 different steroids.
Hormone‐Receptor Interactions. Synthesis of a biologically active cysteinyl‐angiotensin derivative and its use for the preparation of spin‐labelled and polymer‐supported molecules
Authors: Möschler Hans Jörg , Schwyzer Robert
Published: December 2004

(N‐t‐Butoxycarbonyl‐S‐acetamido‐methyl‐L‐cysteinyl)‐[1‐ asparagine, 5‐valine]‐angiotensin II (2) was prepared from [1‐asparagine, 5‐valine]‥angiotensin II (1). With respect to enhancement of rat blood pressure, it is a full agonist displaying about 20–25% of the potency of 1. The sulfur atom of the cysteine group represents a specific nucleophile by which the hormone can easily be attached to other molecules in a well‐defined manner. Thus, 2 has been added to N‐substituted maleimides through its (deprotected) thiol group to produce the spin‐labelled derivative 3:{N‐t‐butoxy‐carbonyl‐S‐[N‐(1‐oxy‐2,2,5,5‐tetramethyl‐ pyrrolidin‐3‐yl‐methyl)‐imidosuccin‐3‐yl]‐L‐cysteinyl}‐[1‐asparagine,5‐valine]‐angiotensin II, and the polymer‐supported derivative 6: S‐(N‐{5‐[7‐(sepharosyl‐oxy‐carbonimidoyl‐amino)‐4‐azaheptylcarbamoyl]‐pentyl}‐imidosuccin‐3‐yl)‐L‐cysteinyl‐[1‐asparagine, 5‐valine]‐angiotensin II. The ESR. spectra of 3 in different solvents, and its principal NMR. characteristics, are reported. We are using the compound for studying its interaction with receptor molecules and for purification of target cells and membrane vesicles by affinity aggregation.
Thermische Umlagerung von Propargyloxy‐cycloheptatrien‐Derivaten
Authors: Pryde Andrew , Zsindely Janos , Schmid Hans
Published: December 2004

The thermal rearrangement of 7‐propargyloxy‐cycloheptatriene in decane solution at 180°C gave bicyclo[3.3.2]deca‐3,7,9‐trien‐2‐one (13) and the unstable 2,7‐dihydro‐cyclohepta[b]‐pyran (12) (Scheme 2). The structures of these compounds were determined mainly by NMR. spectroscopy. Derivatives of 13 were also identified by comparison with known compounds (Scheme 3). Possible mechanisms for the formation of 13 and 12 are outlined in Schemes 5 and 6 respectively.

The thermal rearrangement of 2‐propargyloxy‐cycloheptatrienone (21) gave, in high yield, 2‐methyl‐8H‐cyclohepta[b]furan‐8‐one (22) (Scheme 7).
Einsatz von Hochleistungs‐Trennkapillaren in der GC.‐EIMS./GC.‐CIMS.‐Analyse: Eine Möglichkeit zur massenspektrometrischen Doppelbindungscharakterisierung in komplexen Monoalkengemischen
Authors: Blum Wolfgang , Richter Wilhelm J.
Published: December 2004

In an attempt to determine position and substitution of double bonds in complex mixtures of straight‐chain and branched monoalkenes without actually isolating the constituents, GC.‐MS. analysis is performed after in‐batch preparation of derivatives of a judiciously chosen type. Cyclic phenylboronates (4,5‐substituted 2‐phenyl‐1,3,2‐dioxaborols) are prepared from 1,2‐diols which are, in turn, obtained from the original alkenes by treatment with osmium tetroxide. Chemical ionization mass spectrometry (CIMS.) is used in addition to conventional electron impact techniques (EIMS.) in sequential GC./CIMS.‐ and GC./EIMS.runs, yielding complementary structural information for the single components of the mixture. In order to cope with the potential severity of the separation problem, high‐efficiency glass capillary columns were employed throughout. The performance of the system used is demonstrated by a complete double bond analysis of a 35‐component mixture of monoalkenes in the C5 to C9 range.
Etude par résonance paramagnétique électronique du radical (ΦNH)2P• piégé dans un monocristal de diphenylamino‐phosphineoxyde irradié aux rayons X
Authors: Ginet Lucien , Geoffroy Michel
Published: December 2004

The radical (ΦNH)2P· is trapped by annealing at 100°C an X‐irradiated single crystal of NN diphenyl phosphondiamide and has been studied by electron spin resonance. The isotropic and anisotropic 31P coupling constants are discussed. The principal values and direction cosines of the g tensor are also given.
A Short Stereoselective Total Synthesis of Racemic Patchouli Alcohol. Preliminary communication
Authors: Näf Ferdinand , Ohloff Günther
Published: December 2004

A stereoselective four‐step synthesis of racemic patchouli alcohol starting from the known 2,6,6‐trimethyl‐2,4‐cyclohexadien‐1‐one [1] and 3‐methylpent‐4‐en‐1‐ol [2] is described.
Arbeiten über Phosphorsäure und Thiophosphorsäureester mit einem heterocyclischen Substituenten 9. Mitteilung 1. Aza‐Analogie I: Aza‐Analoge von Phthalimid‐, Benztriazol‐ und 1,2,3‐Benztriazin‐4(3H)‐on‐Derivaten
Authors: Rüfenacht Kurt
Published: December 2004

Aza‐analogues of the known pesticidal dithiophosphates 2, 4 and 5 have been prepared by replacing the phthalimide, benzotriazole and 1,2,3‐benzotriazin‐4(3H)‐one moieties resp. in 2 by those of quinolinic acid imide (6), cinchomeronic acid imide (7) and pyrazine‐2,3‐dicarboxylic acid imide (12), in 4 by 1H‐v‐triazolo[4,5‐b]pyridine (15) and in 5 by pyrido[2,3‐e]1,2,3‐triazin‐4(3H)‐one (21). Compared to the known compounds the new esters are less or at best equally pesticidal with an equal or even higher mammalian toxicity.
Preparation of Neutral Ionophores for Alkali and Alkaline Earth Metal Cations and their application in ion selective membrane electrodes
Authors: Ammann Daniel , Bissig René , Güggi Marc , Pretsch Ernö , Simon Wilhelm , Borowitz Irving J. , Weiss Louis
Published: December 2004

The preparation of a series of non‐cyclic, uncharged ligands able to selectively complex alkali and alkaline earth metal cations is described. These molecules are designed to be used as carriers for cations through membranes. Some of the compounds show high Ca2+ and Na+ selectivity, respectively, in liquid membrane electrodes.
Piperaceae Alkaloids: Part I. Structure of piperstachine; 13C‐ and 1H‐NMR. Studies
Authors: Joshi Balawant S. , Viswanathan Narayanan , Gawad Dilip H. , von Philipsborn Wolfgang
Published: December 2004

From the stem of Piper trichostachyon C. DC. a new alkaloid designated piperstachine (VII) has been isolated. Its structure is derived on the basis of spectral data and synthesis of hexahydropiperstachine (X).
The He 584 Å Photoelectron Spectra of Analoga of Thiathiophthene
Authors: Gleiter Rolf , Gygax Ruedi , Reid David H.
Published: December 2004

The photoelectron spectra of the four oxygen and nitrogen analogs of thiathiophthene 1 to 4 are reported and discussed. The first two bands are assigned to ionization from the π‐ and n‐molecular orbitals on the basis of CNDO/2 calculations. The assignment of bands and to ionization from π‐molecular orbitals is suggested.
Selektive Funktionalisierung von Wortmannin mit Hilfe einer Furanring‐Maskierung
Authors: Haefliger Walter , Kis Zoltan , Hauser Daniel
Published: December 2004

Wortmannin (1) and its 11‐desacetoxy derivative 2 are highly susceptible to nucleophiles, which limits the possibilities of transformation. Masking the furan ring by a new method allowed selective transformations with various reagents.
Total Synthesis of Indole and Dihydroindole Alkaloids. VI. The total synthesis of some monomeric vinca alkaloids: dl‐Vincadine, dl‐vincaminoreine, dl‐vincaminorine, dl‐vincadifformine, dl‐minovine and dl‐vincaminoridine
Authors: Kutney James P. , Chan Ka Kong , Failli Amedeo , Fromson John M. , Gletsos Constantine , Leutwiler Albert , Nelson Vern R. , de Souza Joao Pedro
Published: December 2004

A synthetic approach to a variety of monomeric Vinca alkaloids is described. The sequence involves, among its crucial phases, the generation of appropriate nine‐membered ring intermediates which are then elaborated via a transannular cyclization approach to the desired natural products.
Total Synthesis of Indole and Dihydroindole Alkaloids. VII. The total synthesis of isovelbanamine, velbanamine, cleavamine, 18β‐carbomethoxycleavamine and catharanthine
Authors: Kutney James P. , Bylsma Feike
Published: December 2004

A synthesis of a variety of nine‐membered ring intermediates in the cleavaminevelbanamine series is described. The formation of the penultimate intermediate involves a fragmentation reaction in which the cleavamine system is generated from an appropriate rigid pentacyclic Iboga alkaloid derivative. Thus dihydrocatharanthinol tosylate (VIII) on reaction with triethylamine in refluxing benzene undergoes fragmentation to the 5, 18‐seco‐diene X. This latter substance is then elaborated in various ways to the desired compounds.
Darstellung und Charakterisierung von (±)‐Coralydin und (±)‐O‐Methylcorytenchirin und ihrer optischen Antipoden (Vorläufige Mitteilung)
Authors: Bruderer Hans , Metzger Jean , Brossi Arnold
Published: December 2004

The synthesis and characterization of (±)‐coralydine and (±)‐O‐methylcorytenchirine and their optical isomers are described.
Steroide und Sexualhormone 256. Mitteilung 1. Quassinoide Bitterstoffe I 1‐Oxo‐2‐methoxy‐4α‐methyl‐17β‐hydroxy‐Δ2‐5α‐androsten als Modell für den Ring A des Quassins
Authors: Jörg Koch Hans , Pfenninger Hans , Graf Walter
Published: December 2004

Starting from 3‐oxo‐17β‐hydroxy‐Δ1‐5α‐androstene (2b) the preparation of 1‐oxo‐2‐methoxy‐4α‐methyl‐17β‐hydroxy‐Δ2‐5α‐androstene (9), a compound with the ring A structure of quassine (1) is described. The key problem of the reaction sequence is shown to be the monomethylation at C(4).
Dérivés C‐glycosyliques XXVI. Nouvelles voies d'accès à des C‐nucléosides isoxazoliques et thiophéniques Communication préliminaire
Authors: Tronchet Jean M. J. , Martin Olivier , Zumwald Jean‐Bernard , Le‐Hong Nghiep , Perret Françoise
Published: December 2004

3‐O‐benzyl (and 3‐O‐methyl)‐1,2‐O‐isopropylidene‐α‐D‐xylo‐dialdo‐1,4‐furanoses treated with bromocyanomethylidene‐ or bromoacylmethylidene‐triphenylphosphoranes gave in good yields the corresponding olefinic sugars. These compounds, which bear three adjacent electrophilic carbon atoms (C(5), C(6), C(7)) constitute useful synthetic intermediates in carbohydrate chemistry. They represent, for example, good starting materials for the preparation of 3‐glycosylisoxazoles, 5‐glycosylisoxazoles and 2‐glycosylthiophenes.
Die stereospezifische Reduktion von (1R)‐3‐endo‐Aminocampher zu (1R)‐3‐endo‐Aminoborneol
Authors: Pauling Horst
Published: December 2004

The highly stereospecific reduction of (1R)‐3‐endo‐aminobornan‐2‐one (2) to [1R]‐3‐endo‐amino‐2‐endom‐bornanol (1) is described. This reaction is achieved by using alkylaluminumdichlorides, a new group of reducing agents for the reduction of the ketone 2 to the secondary alcohol 1

Diesc Reduktion ist Gegenstand van Patcntanmeldungen, z. B. [l].
Les pseudonitrosites en chimie organosilicique
Authors: Jolibois Henri , Doucet André , Perrot Roger
Published: December 2004

The reaction of dinitrogen trioxide with seven silanes containing an ethylenic chain, lead to pseudonitrosites.
Totalsynthese von Betalainen
Authors: Hermann Kurt , Dreiding André S.
Published: December 2004

A total synthesis of betalaine pigments (6) is described. The key intermediate is betalamic acid in the form of its dimethyl ester semicarbazone (9), which was transformed with L‐proline (16) into indicaxanthine dimenthl ester (5), with L‐cyclodopa methul ester (17) into betanidine trimethyl ester (3) and by hydrolysis of the latter into betanidine (2).
Triasteranetrione from Triasteranedione
Authors: Chapleo Christopher B. , McDonald Ian A. , Dreiding André S.
Published: December 2004

Reaktion von Triasterandion (1) mit N‐Bromsuccinimid ergab 44% 9‐Brom‐triasterandion (5), neben wenig 9,9‐Dibrom‐triasterandion (6). Substitution des Bromatoms in 5 durch eine Acetoxygruppe ergab 74% 9‐Acetoxy‐triasterandion (10). Umesterung mit Natriumäthylat und Oxydation des rohen Hydroxy‐diketons 9 führte zu Triasterantrion (2). Versuche, Triasteranon (11) mit N‐Bromsuccinimid in 3,5‐Dibrom‐triasteranon (7) umzuwandeln, waren ohne Erfolg.
Synthèse de spiro‐pyrazolines par cycloaddition du diazométhane sur des sucres insaturés ramifiés. Influence de l'isomérie géométrique sur l'orientation de la réaction Communication préliminaire
Authors: Tronchet Jean M. J. , Gentile Bernard , Tronchet Jeannine
Published: December 2004

The orientation of the cycloaddition of diazomethane on unsaturated branchedchain sugars has been studied. For 3‐C‐cyanomethylidene‐3‐deoxy‐1,2‐O‐isopropylidene‐α‐D‐glycero‐tetrofuranose the orientation was ‘normal’ and did not depend on the configuration at the double bond. The same situation prevailed with derivatives of 3‐deoxy‐1,2:5,6‐di‐O‐isopropylidene‐3‐C‐methylidene‐α‐D‐xylo‐hexofuranose. For the 3‐C‐acylmethylidene‐ and the 3‐C‐cyanomethylidene‐3‐deoxy‐1,2:5,6‐di‐O‐isopropylidene‐α‐D‐ribo‐hexofuranoses, the trans‐(H–C(3′)–C(2))‐isomer gave the ‘normal’ cycloadduct whereas the cis‐isomer gave predominantly the αabnormal spiro‐pyrazoline. This observation represents the first instance where the regioselectivity of a cycloaddition reaction is affected by the geometrical isomerism of the dipolarophile. The most probable explanation of the phenomenon is the conformational perturbation about the C(4)‐‐C(5) bond of the unsaturated sugars induced by a change in the configuration at C(3). The consequence of that ‘conformational transmission’ of a difference in configuration at C(3) is that the steric crowding on the cis‐ than in the trans‐isomer. Several novel examples of a new series of C‐glycosylidenic derivatives, the spiro‐pyrazolines, are described.
Synthese und HOFMANN‐Abbau des 1‐(Diphenyl‐hydroxymethyl)‐2,2‐dimethyl‐6,7‐dimethoxy‐1,2,3,4‐tetrahydroisochinolinium‐Ions
Authors: Wiegrebe Wolfgang , Rohrbach‐Munz Barbara , Awe Walter , Kirk Olaf
Published: December 2004

The synthesis of the N‐quaternary aminoalcohol 6 is described. Analogous to the aminoalcohols 1 and 2, 6 on treatment with alkali undergoes fission of the substituent at C(1) as a carbonyl compound, with formation of a N, N‐dimethyl‐1,2,3,4‐tetrahydroisoquinolinium ion, which is further degraded to the corresponding o‐vinyl‐benzylamine (Scheme1). – As a by‐product of a Bischler‐Napieralski ring closure, we observed chlorination of an aromatic ring (yielding 19).
Synthesis of Heparin Saccharides III. Synthesis of Derivatives of D‐Glucosamine as Starting Materials for Disaccharides
Authors: Wyss Pierre C. , Kiss Joseph
Published: December 2004

Derivatives of benzyl 2‐[1‐(benzyloxy)formamido]‐2‐deoxy‐α‐D‐glucopyranoside with various protecting groups at C(3) (benzoyl, benzyl and N‐phenylcarbamoyl) and C(6) (benzoyl, benzylsulfonyl, N‐phenylcarbamoyl and tosyl) have been synthesized as starting materials for disaccharides. The C(4) and C(6) hydroxyl groups of the amino sugar were initially blocked by an acetal group. After introduction of the protecting group at C(3), the acetal group was removed by acid hydrolysis, and the C(6) hydroxyl group was selectively acylated or sulfonylated. The 3,6‐di‐O‐benzoate has also been prepared by dimolar benzoylation of the amino sugar, whereby the 4,6‐isomer was obtained as a by‐product.
Synthesis of Heparin Saccharides IV. Synthesis of disaccharides possessing the structure of a repeating unit of heparin
Authors: Wyss Pierre C. , Kiss Joseph , Arnold Wolf
Published: December 2004

The synthesis of disaccharides possessing the structure of a repeating unit of heparin is reported. 2‐Acetamido‐2‐deoxy‐4‐O‐(methyl α‐D‐glucopyranosyluronate)‐D‐glucopyranose (1) and 2‐[1‐(benzyloxy)formamido]‐2‐deoxy‐4‐O‐(methyl α‐D‐glucopyranosyluronate)‐D‐glucopyranose (2) have been prepared by two routes, (a) from D‐glucose and D‐glucosamine, and (b) from D‐glucuronolactone and D‐glucosamine.
A Transient Ion Pair (CCl · Cl−) in Irradiated Liquid CCl4: Evidence for a ‘delayed’ geminate ion neutralisation. (Preliminary communication)
Authors: Bühler Rolf E. , Hurni Bendicht
Published: December 2004

Detailed cation scavenger studies in pulse‐irradiated pure, liquid CCl4 reveal that the 500 nm absorption has both, neutral and cationic characteristics, and that CCl4+ must be the precursor. It is shown that all experimental results are compatible with the following ion neutralisation mechanism: CCl + Cl− → (CCl · Cl−) → CCl4.

The 500 nm band is assigned to the CCl3+‐cation (free or complexed). Its neutralisation therefore does not occur on ion recombination, but is delayed by the life time of the ion pair: τ½ (ion pair) = 33 ± 3 ns at −22°C with activation energy of 10.9 ± 2.1 kJ/mol. Possible reasons for the ion pair stability are briefly discussed.
Synthese der diastereomeren 4‐Amino‐ und 4‐Hydroxy‐3‐(p‐chlorphenyl)‐valeriansäuren. Kristallstruktur von cis‐4‐(p‐bromphenyl)‐5‐methyl‐2‐pyrrolidinon
Authors: Bruderer Hans , Arnold Wolf , Oberhänsli Willy E.
Published: December 2004

Synthesis of 4‐amino‐ and 4‐hydroxy‐3‐(p‐chlorophenyl)‐valeric acids. X‐ray structure of cis‐4‐(p‐bromophenyl)‐5‐methyl‐2‐pyrrolidinone

The syntheses of diastereomeric 4‐amino‐ and 4‐hydroxy‐3‐(p‐chlorophenyl)‐valeric acids and of their ring closure products (lactones and lactams), starting from 3‐(p‐chlorophenyl)‐4‐oxo‐valeric acid, are described. A single‐crystal X‐ray structure analysis of cis‐4‐(p‐bromophenyl)‐5‐methyl‐2‐pyrrolidinone is given. Some aspects of the biochemistry of threo‐3‐(p‐chlorophenyl)‐4‐amino‐valeric acid are presented.
11. Anil‐Synthese. 16. Mitteilung. Über die Herstellung von styryl‐derivaten des 2‐phenyl‐imidazo [1,2‐a]pyridins
Authors: Pauchard Jean‐Paul , Siegrist Adolf Emil
Published: December 2004

Preparation of styryl derivatives of 2‐phenyl‐imidazo [1, 2‐a]pyridine

2‐(p‐Tolyl)‐imidazo [1, 2‐a]pyridines and 7‐methyl‐2‐phenyl‐imidazo [1,2‐a]‐pyridines can be converted, in dimethylformamide, on reaction with anils of aromatic aldehydes in the presence of potassium hydroxide or potassium t‐butoxide, into the corresponding 2‐(stilben‐4‐yl)‐ and 2‐phenyl‐7‐styry1‐imidazo [1, 2‐a]‐pyridines (‘Anil‐Synthesis’). The 2‐(p‐tolyl)‐imidazo [1,2‐a]pyridines react far less readily than the 7‐methyl‐2‐phenyl‐imidazo[1,2‐a]pyridines.
Triplet‐Triplet Absorption Spectroscopy of Some Highly Dipolar Unsaturated Nitro Compounds
Authors: Cowley David J.
Published: December 2004

The triplet‐triplet absorption spectra of p‐N, N‐dimethylnitroaniline, 4‐nitro‐p‐terphenyl, 1‐amino‐4‐nitrofluorene, 5‐nitroacenaphthene, trans‐1‐(4‐methoxy‐phenyl)‐2‐nitroethylene (MeONS), and trans‐1‐(4‐dimethylaminophenyl)‐2‐nitroethylene (DANS) in EPA glass at 77 K are reported, together with molar extinction coefficients and PPP‐SCF‐MO‐CI calculations. The two nitrostyrenes, MeONS and DANS, have been examined in fluid media at room temperature using nanosecond laser photolysis, and their triplet lifetimes found to increase substantially with increase in solvent polarity and charge‐transfer character of the compound. This is interpreted in terms of the diradical/zwitterionic nature of the triplet state affecting the T1–S0 energy gap at the 90° twisted configuration of the olefinic linkage.

The decrease in both the triplet yield and the fluorescence yield of DANS with increase in solvent polarity is explained by the intervention of an internal conversion process involving a rotation of the dimethylamino group in the lowest singlet excited state.
A New Synthesis of 2,3,1‐Diazaborines
Authors: Müller Beat W.
Published: December 2004

A new method for the preparation of 2,3,1‐diazaborines is described. It is suggested that the observed formation of the C,B‐bond by electrophilic attack with a boron halide is facilitated and o‐directed by the sulfonyl hydrazone group of the educts.
Inhaltsstoffe des Osmanthus‐Absolues. 2. Mitteilung: 2,7‐Epoxy‐megastigma‐4,8(E)‐dien
Authors: Kaiser Roman , Lamparsky Dietmar
Published: December 2004

Constituents of Osmanthus Absolute, 2nd communication: 2,7‐Epoxy‐megastigma‐4,8 (E)‐diene

The characteristic fragmentation pattern in the mass spectrum of 2,7‐epoxy‐dihydro‐α‐ionone bearing a new oxabridged ionone skeleton has lead to the identification of a further trace component in Osmanthus absolute, the 2,7‐epoxy‐megastigma‐4,8(E)‐diene. The synthesis was performed in three steps starting from the above mentioned new ionone derivative now synthetically available by base treatment of 2‐hydroxy‐α‐ionone [1].
Inhaltsstoffe des Osmanthus‐Absolues. 3. Mitteilung: Derivate der theaspirane
Authors: Kaiser Roman , Kappeler Annemarie , Lamparsky Dietmar
Published: December 2004

Constituents of Osmanthus‐Absolute, 3rd communication: Derivatives of Theaspiranes

Four isomeric new 7‐oxo‐dihydrotheaspiranes were identified in Osmanthus absolute. Their configuration was proved by synthetic correlations with racemic as well as optically active theaspiranes A and B. These two compounds also occurring in the same natural substrate were first correlated with the (−)‐theaspirone A of known absolute configuration and the (+)‐theaspirone B, respectively, thus giving the background for all further stereochemical relationship work. In depth studies in the 1H‐ and 13C‐NMR.‐spectroscopy field including all possible and now synthetically available hydroxy derivatives of the new oxo compounds enabled us to unambiguously assign structures 1 to 4 to the natural products. Some further constituents bearing the same spirocyclic skeleton were also detected in Osmanthus absolute.
CH‐Acidität in α‐Stellung zum N‐Atom in N,N‐dialkylamiden mit sterisch geschützter Carbonylgruppe zur nucleophilen minoalkylierung
Authors: Schlecker Rainer , Seebach Dieter , Lubosch Winfried
Published: December 2004

CH‐Acidity in α‐position to the N‐Atom of N, N‐Dialkylamides with Sterically Protected Carbonyl Groups Contribution to the Nucleophilic Amino Alkylation

Sterically protected amides 1 such as the 2,4,6‐triisopropyl‐benzoic acid derivatives 3, 8b and 10 undergo readily H/Li‐exchange with s‐butyllithium at the CH3N‐ or CH2N‐groups. The resulting organolithium compounds (cf. 9, 11) are alkylated and hydroxyalkylated with primary haloalkanes, aldehydes, and ketones under chain elongation in the amine position of the amides. The (E/Z)‐rotamers of the dialkylamides 7 and 8are separated by chromatography; the amides 4–6, 12, and 13 formally derived from β‐hydroxyamines are obtained in the (Z)‐form only. The configurational (E/Z)‐assignments follow from NMR. and IR. data. The erythro and threo configuration of the two diastereomeric amides 12a and 12b are tentatively concluded from Eu(fod)3‐1H‐NMR.‐shift experiments. The results strongly suggest that the H/Li‐exchange takes place regioselectively at the CHN group which is in cis‐position to the CO double bond (→14). The methyl 2,4,6‐tri(t‐butyl)benzoate (18) can also be deprotonated to the lithium acyloxymethanide 19 which is trapped by alkylation with 1‐iodooctane (→20). – The steric protection of the carbonyl groups in the products 4–8, 10, 12, 13, and 20 prevents their ready hydrolysis to amines and alcohols, respectively. Therefore, triphenylacetic acid derivatives 21 rather than 2,4,6‐triisopropylbenzoic acid derivatives for use in the electrophilic substitution of equation (1) are recommended. The trityl group in 21 may be considered a C‐leaving‐group (CC protective group, cf. 22, 23). The acetamide 25 reacts readily (→26) and then with electrophiles to give products 27a–c. As shown in the Table, the amides 27 are cleaved under a variety of conditions with formation of triphenylmethane. LiAlH4 produces a tertiary amine, CH3Li a secondary amine, and dissolving alkali metals/naphthalene under aprotic conditions mixtures of secondary amine and its formamide (hydrolysed by acid treatment). Thus the overall process (2) is feasible.
Das Zweiphasenystem Oxinschmelze/Wasser zwischen 75 und 100°
Authors: Magyar Balazs , Vonmont Heinz
Published: December 2004

The two phase system oxyne melt/water between 75 and 100°

The density, mutual solubility of oxine and water were determined. Using these data the volumes of the coexisting phases can be calculated from the originally weight‐in quantity of oxine and water in extraction experiments. The acidity constants of oxine between 65 and 95° were also determined and the temperature dependence of the pK‐values is discussed.
Triazènes et benzotriazines dérivés de sucres
Authors: Tronchet Jean M. J. , Rachidzadeh Faranak
Published: December 2004

Sugar triazenes and benzotriazines

Several triazenylsugars have been prepared, generally in good yields, by treating an amino sugar with a substituted benzenediazonium salt. The triazenylsugars bearing a hydrogen atom on the triazenyl group are acetylated on the nitrogen atom closest to the glycosyl moiety (N(1)), even when the proton exchanged sites between N(1) and N(3). When an acetyl or a methoxycarbonyl group was present in the ortho position of the benzene ring cyclization took place leading to a 3,4‐dihydro‐4‐methylidene‐1,2,3‐benzo[d]triazine or a 3,4‐dihydro‐1,2,3‐benzo[d]triazin‐4‐one respectively.
Durch elektrisch geladene Ionophore induzierter Ionentransport in Modellmembranen mit Selektivität für Magnesium und Calcium
Authors: Erne Daniel , Morf Werner E. , Arvanitis Spyridon , Cimerman Zvjezdana , Ammann Daniel , Simon Wilhelm
Published: December 2004

Different lipophilic β‐diketones have been prepared. Some preferably transport Mg2+ and Ca2+ through PVC‐based liquid membranes when a pH‐gradient is applied across the membrane. A theoretical model is presented that allows a description of potentiometrically determined ion selectivities as well as transport selectivities obtained under zero current and electrodialytic conditions, respectively. The expectations based on this model are in agreement with the experimental evidence presented. Some membrane systems have potentiality for their application in the measurement of water hardness.
Stereospezifische Fragmentierungen in den Massenspektren von Cyclohexandiaminen und Bis(aminomethyl)cyclohexanen. 33. Mitteilung über massenspektrometrische Untersuchungen,,
Authors: Süess Hans , Hesse Manfred
Published: December 2004

Stereospecific Fragmentations in the Mass Spectra of Cyclohexanediamines and Bis(aminomethyl)cyclohexanes

The mass spectral behaviour, especially loss of NH3, of the six isomeric cyclohexanediamines 1‐‐3 (cis and trans each, Scheme 1) as well as of the six isomeric bis(aminomethyl)cyclohexanes 4‐‐6 (cis and trans each, Scheme 6) has been investigated. The cis‐ and trans‐compounds of the 1,2‐isomers 1 and 4 show very similar spectra, because of the ease of ring cleavage at C(1)–‐C(2) and the similar geometrical relations in all ring conformations. The cis‐ and trans‐compounds of both the 1,3‐ and 1,4‐isomers 2, 3, 5 and 6 show striking differences in their mass spectra due to stereospecific elimination of NH3 from the molecular ion.
The Absolute Configuration of 1‐Methylindane
Authors: Hansen Hans‐Jürgen , Sliwka Hans‐Richard , Hug Werner
Published: December 2004

It is shown unequivocally by chemical correlations (cf. Schemes 1‐‐3) and Raman optical activity spectra (cf. Fig. 1 and 2) that the (R)‐configuration has to be attributed to (+)‐1‐methylindane ((+)‐1). This is in contradiction to an earlier assignment of the (R)‐configuration to (−)‐1[2] which was based on the (R)‐configuration of (+)‐indane‐1‐carboxylic acid (3) [11].
4‐Azidoaniline, a Versatile Protein and Peptide Modifying Agent for Photo Affinity Labeling
Authors: Escher Emanuel H. F. , Robert Hélène , Guillemette Gaétan
Published: December 2004

A modified synthesis of 4‐azidoaniline and the use of this compound as a protein and peptide modifying agent for photoaffinity labeling is described. 4‐Azidoaniline was diazotized to 4‐azidophenyldiazonium and coupled to N‐acetyl‐tyrosine‐ethylester, and to a tyrosine containing analog of bradykinin.

It is shown that the 4‐azidoaniline reagent offers great advantages over other protein modifying agents for photoaffinity labeling, i.e., very high nitrene reactivity, possibility of tritium or iodine labeling, ligand‐receptor complex can be cleaved after isolation. The biological activity of the modified bradykinin analog is measured on rabbit aorta strip in the dark and is similar to the unsubstituted analog. Under the influence of light the modified peptide is able to block partially the myotropic action of bradykinin.
Synthese und Konfiguration einiger Spiro [indan‐2,2′‐pyrrolidin]‐ und Spiro [pyrrolidin‐2,2′‐tetralin]‐Derivate,
Authors: Stoll André P. , Petcher Trevor James , Weber Hans Peter
Published: December 2004

Synthesis and configuration of some spiro [indan‐2,2′‐pyrrolidine] and spiro [pyrrolidine‐2,2′‐tetraline] derivatives

Catalytic hydrogenation of the nitrosoindan and nitrosotetralin derivatives 8 yielded trans‐1‐hydroxy‐spiro [indan‐2,2′‐pyrrolidin]‐5′‐one (9) and trans‐1′‐hydroxy‐spiro [pyrrolidine‐2,2′‐tetralin]‐5‐one (10) respectively, whilst the corresponding cis compounds 12 and 15 were prepared via the chlorides 11 and 14.

The configurations of 10 and 13 were determined by X‐Ray analysis.
Über die Synthese des Muscaflavins. Vorläufige Mitteilung,
Authors: Barth Hubert , Kobayashi Makoto , Musso Hans
Published: December 2004

Synthesis of muscaflavin

A biomimetic type synthesis of the yellow dihydroazepine amino acid 5 isolated from fly agaric is achieved starting with carboxypyridyl alanine derivatives.
Cynaratriol, ein neues Guajanolid aus der Kardone Cynara cardunculusL. und der Artischocke C. scolymusL.(Compositate)
Authors: Bernhard Heinz O. , Thiele Kurt , Pretsch Ernö
Published: December 2004

Cynaratriol, a new guajanolide from Cynara cardunculus L. and C. scolymus L. (Compositae)

A new guajanolide given the name cynaratriol (4) was isolated from the leaves of Cynara cardunculus L The structure of 4 and its derivatives 3, 11, 13‐triacetylcynaratriol (5) and 3, 13‐dibenzoyl‐cynaratriol (6) was deduced on the basis of IR.‐, 1H‐NMR.‐, 13C‐NMR.‐ and mass spectroscopic data. 4 is also present in C. Scolymus L. as shown by GC./MS. analysis. The same absolute configuration is suggested for 4 as found for all other Cynara sesquiterpenes.
On the Claisen Rearrangement of Allyl Ethyl Ketene Acetals Generated in situ via Benzeneselenenic Acid Eliminiation
Authors: Pitteloud Rita , Petrzilka Martin
Published: December 2004

Mixed acetals 7 of benzeneseleninylacetaldehyde, prepared by a simple 2‐step procedure from mono‐ and bicyclic allylic alcohols 5, undergo benzeneselenenic acid elimination to transient ketene acetals 8 which afford γ, δ‐unsaturated esters 9 via the ester Claisen rearrangement (Scheme 2). Under the same conditions selenoxide 7h derived from benzyl alcohol 5h is converted back to benzyl alcohol with the concomitant formation of ethylphenylselenoacetate 12.
Zur Biogenese der Betacyane: Versuche mit [2‐14C]‐Dopaxanthin
Authors: Wyler Hugo , Meuer Ursula
Published: December 2004

On the biogenesis of betacyanins. Expaiments with [2‐14C]‐dopaxanthine

Labelled dopaxanthine is prepared from betanin by a double exchange procedure replacing first its cyclodopa part by diethylamine and effecting the second exchange with 2‐[14C]‐dopa on the purified intermediate ‘DEA‐betalain’; the specific activity delivered with the dopa allowed accurate determination of ϵ in the electronic spectrum of dopaxanthine (λmax 488 nm, ϵ = 41.800). The C(2)‐labelled dopaxanthine is incubated into the fruits of Opuntia bergeriana. The incorporation rates into betanin are found to correspond approximately to those obtained in earlier experiments with labelled dopa alone: Only 1‐‐5% of the label showed up in the cyclodopa moiety of the betanin (which is isolated as cyclodopa‐glucoside) whereas 99‐‐95% of the radioactivity was associated with the betalamic acid part (recovered in form of indicaxanthine).
The Radical Anions of 5,5′‐ and 6,6′‐Biazulenyl
Authors: Gerson Fabian , Lopez Javier , Metzger André , Jutz Christian
Published: December 2004

ESR. and, in part, ENDOR. studies are reported on the radical anions of 5,5′‐and 6,6′‐biazulenyl (1 and 2, resp.), as well as on their 1, 1′, 3, 3′‐tetradeuterioderivatives (1‐d4 and 2‐d4). The reduction processes of 1 and 2 leading to these radical anions (\documentclass{article}\pagestyle{empty}\begin{document}$ 1^{\ominus \atop \dot{}}$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ 2^{\ominus \atop \dot{}}$\end{document}) and the dianions (
equation image
) have been investigated by polarography and cyclic voltammetry. The half‐wave reduction potential of 1 and the π‐spin distribution in \documentclass{article}\pagestyle{empty}\begin{document}$ 1^{\ominus \atop \dot{}}$\end{document} are consistent with the model of two weakly interacting azulene π‐systems, whereas the analogous findings for 2 and \documentclass{article}\pagestyle{empty}\begin{document}$ 2^{\ominus \atop \dot{}}$\end{document} point to a strong interaction between two such systems. This difference can be traced to the distinct inequality ∥c65 ∥ « ∥ c66 ∥ in the LCAO coefficients c6μ at the centres μ=5 and 6 for the LUMO Ψ6 of azulene.
The Radical Ions of Naphtho [1,8‐cd]‐[1,2,6]thiadiazine and Some of Its Derivatives
Authors: Gerson Fabian , Plattner Georges , Bartetzko Richard , Gleiter Rolf
Published: December 2004

The radical cations and anions of naphtho [1,8‐cd]‐[1,2,6]thiadiazine (1) and 6,7‐dihydroacenaphtho [5, 6‐cd]‐[1,2,6]thiadiazine (2), as well as the radical anion of acenaphtho [5, 6‐cd]‐[1,2,6]thiadiazine (3) have been characterized by ESR. spectroscopy. The π‐spin distributions in the radical cations \documentclass{article}\pagestyle{empty}\begin{document}$ 1^{\oplus \atop \dot{}}$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ 2^{\oplus \atop \dot{}}$\end{document} strongly resemble those in the iso‐π‐electronic phenalenyl radical. A prominent feature of the radical anions \documentclass{article}\pagestyle{empty}\begin{document}$ 1^{\ominus \atop \dot{}}$\end{document}, \documentclass{article}\pagestyle{empty}\begin{document}$ 2^{\ominus \atop \dot{}}$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ 3^{\ominus \atop \dot{}}$\end{document} is the substantial localization of the π‐spin population on the thiadiazine fragment. These findings are satisfactorily accounted for by HMO models using conventional heteroatom parameters.
Conversion of Amines into Phenylsulfides and Phenylselenides via Ditosylamides
Authors: Müller Paul , Thi Minh Phuong Nguyen
Published: December 2004

Amines are converted in good to excellent yields to phenylsulfides or phenyl‐selenides via nucleophilic displacement on the corresponding ditosylamides. The conversion of (−)‐(S)‐1‐phenylethylamine to the chiral phenylsulfide 6 was found to proceed with inversion of configuration. A simple one‐pot procedure for the preparation of ditosylamides is reported.
Stereochemistry of the Conversion of 1,3‐Chloroalcohols in Alkaline Medium. The Chemistry of 1,3‐Bifunctional Systems. XXII
Authors: Bartók Mihály , Felföldi Károly , Bozöki‐Bartók Gizella
Published: December 2004

The transformations of isomeric 1,3‐chloroalcohols 1–4, with cyclohexane skeleton, were studied in aqueous solution containing barium hydroxide. As regards the compounds with cis‐configuration, 1 gives the oxetane 5 by intramolecular nucleophilic substitution, while 3 gives the unsaturated alcohols 7 and 8 by elimination. In the case of the trans‐isomers 2 and 4, fragmentation reactions occur in competition with elimination. The main reaction kinetic parameters of the transformations of the four compounds were determined.
Photochemische Reaktionen 115. Mitteilung [1]. Zur Photochemie konjugierter γ,δ‐Epoxyenone: Der Einfluss eines Hydroxylsubstituenten in ϵ‐Stellung
Authors: Nakamura Norio , Schweizer Wolfhard Berned , Frei Bruno , Wolf Hans Richard , Jeger Oskar
Published: December 2004

Photochemistry of Conjugated γ,δ‐Epoxyenones: The Influence of a Hydroxy Substituent in ϵ‐Position

On 1n, π*‐ or 1π,π*‐excitation (λ ≥ 347 or λ=254 nm), the ϵ‐hydroxy‐γ;,δ‐epoxyenone 8 undergoes fission of the C(γ)O bond followed by the cleavage of the C(δ)‐C(ϵ) bond. This hitherto unknown sequence of reactions is evidenced by the structure determination of the new type products 10–17 and 25, including a synthetic proof for 12 and the X‐ray analysis of 11 (X‐ray data: triclinic P1; a=7,386(2), b=8,904(4), c=9,684(5)Å; α=82,29(4)°, β=74,46(3)°, γ=82,29(3)°; Z=2).

The selective 1π,π*‐excitation also induces competitive C(γ)‐C(δ) bond cleavage to yield the bicyclic acetal 18 and a ketonium‐ylide intermediate a, which photochemically forms a carbene b giving the allene 19 and the cyclopropene 20.

On 1n,π*‐excitation of the acetate 9 the initial C(γ)‐O bond fission is, in contrast to the behaviour of the corresponding alcohol 8, followed by a 1,2‐methyl shift affording (E/Z)‐28 or by a cyclization‐autoxidation process yielding the lactone 29.
Lipophilic Amides of EDTA, NTA and Iminodiacetic Acid as Ionophores for Alkaline Earth Metal Cations
Authors: Erne Daniel , Stojanac Nada , Ammann Daniel , Pretsch Ernö , Simon Wilhelm
Published: December 2004

A series of electrically neutral lipophilic di‐, tri‐, and tetra‐amides containing tertiary‐amine N‐atoms were prepared in order to investigate their selectivity for alkali and alkaline earth metal cations in solvent polymeric membranes. Considerable selectivity changes were observed for membranes incorporating certain of these ligands as compared with ligand‐free membranes. A 1:1 cation/ligand complex was isolated from N, N′, N″‐triheptyl‐N, N′, N″‐trimethyl‐nitrilotriacetamid and Mg (SCN)2 whereas with Ca (SCN)2 the corresponding 2:3 cation/ligand complex was formed. N, N′, N″, N‴, N‴‐tetramethyl‐ethylenediaminetetraacetamide yields a 1:1 cation/ligand complex with Mg (SCN)2.
Beitrag zur massenspektrometrischen retro‐Diels‐Alder‐Reaktion: 1,2,3,4‐Tetrahydrophenanthren. 35. Mitteilung über massenspektrometrische Untersuchungen
Authors: Huggenberg Sonja , Hesse Manfred
Published: December 2004

Contribution to the Mass Spectral retro‐Diels‐Alder Reaction: 1,2,3,4‐Tetrahydrophenanthrene

[1,4‐13C]‐1,2,3,4‐Tetrahydrophenanthrene (1) was synthesized starting from [1,4‐13C]‐succinic acid. The mass spectral behavior (EI./MS., 70eV) of 1 is very similar to that of tetraline [2] concerning its loss of ethylene from the molecular ion. Similarly the fragmentation reaction of the synthetic precursors, ketones 7 and 8, seems to partly undergo a carbon rearrangement reaction prior to the elimination of ethylene which is unlike to the behavior of α‐tetralone.
Steroids and sex hormones. Part 262. The radical induced stannane reduction of selenoesters and selenocarbonates: A new method for the degradation of carboxylic acids to nor‐alkanes and for desoxygenation of alcohols to alkanes
Authors: Pfenninger Johannes , Heuberger Christoph , Graf Walter
Published: December 2004

Esters of carboselenoic acids, formed from carboxylic acids by conventional methods, undergo reaction with tributyltin hydride in inert aromatic solvents, either by heating to give the corresponding aldehyde or the corresponding alkane depending on reaction temperature and the structure of the parent carboxylic acid, or by ultraviolet irradiation at ambient temperature when the aldehyde is formed predominantly in high yield. In the case of esters of α, β‐unsaturated carboselenoic acids the thermal reaction leads only to the corresponding aldehyde.

The above stannane reduction can also be applied to selenocarbonates of primary and secondary alcohols (prepared from the corresponding chloroformates), to give the alkane, the parent alcohol and the corresponding formate, in relative amounts depending on the reaction temperature.

These reactions thus constitute preparatively useful and high‐yield degradation methods compatible with the presence of many other functional groups.
Steroids and sex hormons. Part 264. Lewis acid catalyzed reversible [1,5]‐hydride shift in 3,19‐epoxy‐steroids
Authors: Acklin Georg , Graf Walter
Published: December 2004

3β, 19‐Epoxy‐3 α‐methoxy‐steroids (e.g. 1, Scheme 1) are converted into the corresponding 3 α‐methoxy‐19‐oxo compounds (e.g. 3) in the presence of boron trifluoride etherate, via an intramolecular hydride ion transfer from C (19) to (3) which is shown to be an equilibrium process. By subjecting the specifically deuteriated (19 S)‐ and (19 R)‐compounds 1b and 1c to this reaction it was shown to be highly stereoselective.
Synthesis of Pure Al35Cl3 and Al37Cl3
Authors: Geiser Urs , Schmidhalter Beat , Schumacher Ernst
Published: December 2004

Chemically and isotopically pure Al35Cl3 and Al37Cl3 are synthesized from Al (s) and HCl (g). The yield is quantitative and no measurable decrease in isotopic content from HCl to AlCl3 takes place.
Photochemical reactivity of α,β‐unsaturated δ‐lactams: Synthesis of seco‐steroids. Photochemical reactions. XIII [1]
Authors: Cánovas Antonio , Fonrodona Jesús , Bonet Juan‐Julio , Briansó Marie Claire , Briansó José Luis
Published: December 2004

The UV. irradiation of 17 β‐hydroxy‐2‐aza‐4‐androsten‐3‐one (1), N‐methyl‐17 β‐hydroxy‐2‐aza‐4‐androsten‐3‐one (3), 17 β‐hydroxy‐4‐aza‐5 β‐androst‐1‐en‐3‐one (2) and N‐methyl‐17 β‐hydroxy‐4‐aza‐5 β‐androst‐1‐en‐3‐one (4), gives rise to 1,10‐seco (from 1 and 3) and 5, 10‐seco (from 2 and 4) steroids.
Die Strukturdynamik von Pentadienylmetall‐Verbindungen mit endständiger Alkyl‐Gruppe: zugleich «stereoselektive» und «stereodefensive» Synthese eines natürlichen Riechstoffes
Authors: Bosshardt Herbert , Schlosser Manfred
Published: December 2004

Structural Dynamics of Pentadienyl Metal‐Compounds Bearing a Terminal Alkyl Substituent: Both ‘Stereoselective’ and ‘Stereodefensive’ Synthesis of a Natural Perfume.

The (2Z, 4E)‐, (2E, 4Z)‐ and (2E, 4E)‐isomers of 2,4‐decadien‐1‐ol (5) have been obtained with high and predictable stereochemical homogeneity starting from both (Z)‐ and (E)‐1, 4‐decadiene. These hydrocarbons were hydroxylated in a reaction sequence consisting of metallation (by means of s‐butyllithium or butyllithium/potassium‐t‐butoxide, giving rise to organometallic intermediates of specific conformation), dimethoxyborylation and oxidation. The different decadienols as well as (2E, 4Z)‐2, 4‐undecadien‐1‐ol were converted into the isovalerates, the ester derived from (2E, 4Z)‐2, 4‐decadien‐1‐ol being a natural flavor component.