bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stereoelectronic Properties, Stereospecificity and Stabilization of α‐Seleno Carbanions. An ab initio Study
Authors: Lehn Jean‐Marie , Wipff Georges , Demuynck Jean 
Published: December 2004

AbstractAn ab initio study of α‐seleno carbanions show that they are subject to appreciable polarization and stereoelectronic effects. Like in α‐thia carbanions, the equatorial e forms are more stable than the axial a forms, one of the stabilizing contributions being the conformation dependent (C‐lone pair, σ* SeZ) interaction. The carbanion stabilizing effect of the α‐Se atom is about 3 kcal/mol larger than that of the sulfur analog. As in the case of the sulfur no specific effect of the d orbitals is found.
Die Struktur von Cyclosporin C
Authors: Traber René , Kuhn Max , Rüegger Artur , Lichti Heinz , Loosli Hans‐Rudolf , von Wartburg Albert 
Published: December 2004

The Structure of Cyclosporin CThe structure of cyclosporin C (2), a minor antifungal metabolite from Trichoderma polysporum (Link ex Pers.) RIFAI has been elucidated. Hydrolytic cleavage and spectroscopic evidence show that cyclosporin C is a neutral oligopeptide of 11 amino acids linked together in a 33‐membered ring. Cyclosporin C (2) differs from the main metabolite cyclosporin A (1) [2] [4] only by containing L‐threonine in the place of L‐α‐aminobutyric acid as has been shown by the conversion of 2 into 1. 13C‐NMR. spectra and study of molecular models suggest that cyclosporin C (2) has the same molecular conformation as 1, which is best described as a twisted β‐pleated sheet held together in a conformationally stable form by intramolecular hydrogen bonding.
Über den Mechanismus der Cope‐Umlagerung
Authors: Wehrli Rudolf , Schmid Hans , Belluŝ Daniel , Hansen Hans‐Jürgen 
Published: December 2004

On the Mechanism of the Cope RearrangementThe rates of the Cope rearrangement of 2,5‐dicyano‐3‐methyl‐hexa‐1, 5‐diene (12), (E)‐ and (Z)‐2, 5‐dicyano‐hepta‐1,5‐diene ((E)‐ and (Z)‐14) as well as of 2, 5‐dimethoxycarbonyl‐3‐methyl‐hexa‐1,5‐diene (13) and (E)‐ and (Z)‐2,5‐dimethoxycarbonyl‐hepta‐1,5‐diene ((E)‐ and (Z)‐15) were measured in decane solution in the temperature range of 50 to 150° (see Tables 5 and 8 to 12). A detailed English summary of this work is given in [1 b].
Photochemical reactions VII [1]. A ‘type A rearrangement’ in the photolysis of a steroidal α, β‐unsaturated lactone
Authors: Ferrer Vicente , Gómez José , Bonet Juan‐Julio 
Published: December 2004

AbstractThe irradiation of 17 β‐hydroxy‐2‐oxa‐androst‐4‐en‐3‐one (1) yield a cyclopropane derivative 2, which is the result of a rearrangement, formally analogous to the ‘type A rearrangement’ of the enones. Two other products, the dihydroxy compound 5 and the dimer 6, have also been isolated (Scheme 1).
Diterpenoide Drüsenfarbstoffe: Coleone S und T aus Plectranthus caninus ROTH(Labiatae), ein neues Diosphenol/trans‐A/B‐6,7‐Diketon‐Paar aus der Abietanreihe
Authors: Arihara Shigenobu , Rüedi Peter , Eugster Conrad Hans 
Published: December 2004

Leaf‐gland Pigments: Coleons S and T from Plectranthus caninus ROTH (Labiatae), New Hydroquinones of the Abietane Series with a Diosphenol/trans‐A/B‐6,7‐Diketone Structure.Coleons S and T were isolated from the more polar fractions from extracts of the above mentioned plant. Coleon S, C20H26O6, has been shown to have structure 1a, and coleon T, C20H26O6, structure 2.
Formation of 5‐Hydroxy‐indan‐2‐one from Attempts to Hydrolyse 9‐Ethylenedioxy‐bicyclo[3.3.1]nonane‐3,7‐dione
Authors: Chapleo Christopher B. , Dreiding André S. 
Published: December 2004

Bildung von 5‐Hydroxy‐indan‐2‐on bei Hydrolyseversuchen mit 9‐Äthylendioxy‐bicyclo[3.3.1]nonan‐3,7‐dionVerschiedene Versuche, 9‐Äthylendioxy‐bicyclo[3.3.1]nonan‐3,7‐dion (2) durch Hydrolyse in das entsprechende Triketon 3 umzuwandeln, führten nur zu 5‐Hydroxy‐indan‐2‐on (4) und in einem Fall auch noch zu etwas 7,9‐Bis(äthylendioxy)‐bicyclo‐[3.3.1]nonan‐3‐on (5). Unter milderen Hydrolysebedingungen reagierte 2 gar nicht.Die Bildung von 4 aus 2 wird über eine Wagner‐Meerwein‐Umlagerung und nach‐folgende Eliminierung von Äthylenglycol formuliert. Das so entstandene Äthylenglycol reagiert mit noch vorhandenem Acetal 2 zum Bis‐acetal 5, was als weitere Bestätigung der Resistenz von 2 gegen Hydrolyse gelten darf.
Electrochemical Reduction of Cyclohex‐2‐enones
Authors: Tissot Paul , Margaretha Paul 
Published: December 2004

AbstractThe electrochemical reduction of the cyclohex‐2‐enones 1a–1e (mercury cathode, CH3CN, Bu4NBF4) was studied by means of cyclic voltammetry, d.c. polarography, coulometry and chemical product analysis. Compounds 1a–1c give a mixture of the hydrodimers 4 and 5 via formation of the radical anion 2 by an irreversible one electron transfer, followed by protonation and dimerization of the allylic radical 3. The 6‐halocyclohex‐2‐enones 1d and 1e exhibit two distinct reduction waves. The first corresponds to an irreversible two electron transfer with formation of the halide anion and the enolate anion 6 which gives 1b by protonation. The second wave corresponds to a quasi‐reversible one electron transfer to 6 to afford the radical dianion 7 (Scheme 2).
n‐π‐Interaction in Enamines and Enaminoketones. A 15N‐NMR. Study
Authors: Schwotzer Willi , Von Philipsborn Wolfgang 
Published: December 2004

Abstract15N‐Chemical shifts of 32 enamines, 11 enaminoketones and 28 closely related amines have been determined with the isotope in natural abundance. In order to eliminate substituent effects, differential chemical shifts Δδ(N) are defined as δN(amine)‐δN(enamine). This parameter is shown to correlate well with the free enthalpy of activation ΔG# for restricted rotation about the NC(α) bond in enamines with extended conjugation. Δδ(N) values of substituted anilinostyrenes correlate also with 13C‐chemical shifts of the β‐carbon in the enamine system and with Hammett σ‐constants of the aniline substituents. The experimental results suggest that differential 15N shifts are a useful probe to study n, π‐interaction in enamines.
Neue Cyclopeptide aus Trichoderma polysporum (LINK EX PERS.) RIFAI: Die Cyclosporine B, D und E
Authors: Traber René , Kuhn Max , Loosli Hans‐Rudolf , Pache Walter , Von Wartburg Albert 
Published: December 2004

New Cyclopeptides from Trichoderma polysporum (LINK EX PERS.) RIFAI: Cyclosporins B, D and ECyclosporins represent a new group of biologically active metabolites produced by Trichoderma polysporum (LINK EX PERS.) RIFAI and other fungi imperfecti. The structures of the main components, cyclosporins A (1) and C(3) have been determined as neutral cyclic oligopeptides composed of 11 amino acids, among them a new C9‐amino acid [2–4]. In addition, three minor metabolites, cyclosporins B, D and E, have now been isolated and characterized. Chemical investigation, spectroscopic evidence and X‐ray analysis led to the structural formulae of cyclosporins B (2) and D (4). Both compounds have the same sequence of amino acids as cyclosporin A (1), with the exception of L‐α‐aminobutyric acid, replaced in cyclosporin B (2) by L‐alanine and in cyclosporin D (4) by L‐valine, respectively. Cyclosporins undergo a characteristic intramolecular N,O‐acyl migration to furnish the corresponding basic isocompounds. The antifungal activities of cyclosporins are reported.
Synthese, Kristallstruktur und thermische Entwässerung von CsMnF4 · 2H2O
Authors: Dubler Erich , Linowsky Lothar , Matthieu Jean‐Pierre , Oswald Hans‐Rudolf 
Published: December 2004

Synthesis, crystal structure and thermal dehydration of CsMnF4 · 2H2OThe preparation of a new fluoromanganate (III)‐complex CsMnF4 · 2H2O is reported. It crystallizes in the monoclinic space group C2 with a = 11.891(2) Å, b = 6.589(1) Å, c = 10.558(1) Å, β = 131.46(1)° and Z = 4. The crystal structure has been solved from diffractometer data by heavy‐atom methods and refined to a conventional R‐value of 1.8% (including the contributions of three hydrogen atoms in measured and one in calculated positions). The structure is characterized by isolated, tetragonally distorted [MnF4(OH2)2]‐octahedra with Mn‐F‐distances from 1.801(8) Å to 1.870(7) Å and Mn‐O‐distances of 2.146(6) Å and 2.268(6) Å. Cesium exhibits an irregular 10‐coordination by 8 F‐atoms and 2 O‐atoms (mean values for the two independent cesium ions: Cs‐F = 3.17 Å and 3.21 Å, Cs‐O = 3.32 Å and 3.29 Å). The [MnF4(OH2)2]‐octahedra are connected to six neighbouring octahedra by hydrogen bonding.The dehydration of the complex has been studied by thermoanalytical methods and power x‐ray‐diffractometry. The unit cell of the dehydrated compound, CsMnF4, is tetragonal with a = 7.936(1) Å and c = 6.341(1) Å. A close relationship to the structure of CsFeF4, which is a superstructure variant of the T1A1F4‐type[6], is indicated by the similarity of the corresponding unit cells and preliminary structure factor calculations. A proposition for the crystal structure of CsMnF4 is developed on the basis of (2 + 2 + 2)‐orthorhombic distorted MnF6‐octahedra.
Specifically (π → π*)‐Induced Cyclohexenone Reactions 4a‐(Z‐1‐Propenyl)‐bicyclo[4.4.0]dec‐1 (8a)‐en‐2‐one and 4a‐Z‐1‐Propenyl‐bicyclo[4.4.0]deca‐1(8a), 7‐dien‐2‐one
Authors: Nobs Frédéric , Burger Ulrich , Schaffner Kurt 
Published: December 2004

Abstract4a‐(Z‐1‐Propenyl)‐bicyclo[4.4.0]dec‐1(8a)‐en‐2‐one (6) and 4a‐(Z‐1‐propenyl)‐bicyclo[4.4.0]deca‐1(8a), 7‐dien‐2‐one (17) undergo an intramolecular hydrogen transfer from the methyl group of the propenyl substitutent to the α‐carbon atom of the enone group, and cyclization to the [4.4.3]propellane derivatives 9 and 30, respectively, when excited in the π → π* wavelength region. The quantum yield for (Z)‐6 → 9 under optimum conditions is 0.29 at 254 nm. These reactions occur specifically from the S2 (π,π*) state, competing with the S2 → T decay. The triplet reactions of 6 are E–Z double‐bond isomerization, double‐bond shift to (E,Z)‐8, and rearrangement to (E)‐10. Further investigations concern some structural limitations in the scope of the reaction type 6 → 9 and enone S2 reactivity in general.
Contribution à l'étude du comportement de la catéchine en milieu alcalin
Authors: Courbat Pierre , Weith André , Albert Alban , Pelter Andrew 
Published: December 2004

Contribution to the study of the behaviour of catechin in alkaline mediumWhen catechin (1) is warmed with aqueous alkali it first undergoes rapid epimerisation. After some time a novel bridged carbocyclic enol, catechinic acid (3) separates out and may be isolated in excellent yield. Eventually catechinic acid isomerises to 2‐(3′,4′‐dihydroxyphenyl)‐3,9‐epoxy‐6‐oxo‐bicyclo[3,3,1]‐non‐7‐en‐8,9‐diol (4) via an open chain anion (5) which is also involved in the epimerisation of catechin. Assignments of structure are given and the equilibria observed are discussed.
Zur Reaktion von monosubstituierten Epoxypropanen mit Benzylamin. 1. Mitteilung über Ringöffnungsreaktionen kleiner Ringe
Authors: Sulser Ueli , Widmer Jürg , Goeth Heinz 
Published: December 2004

Reaction of monosubstituted epoxypropanes with benzylamineThe reaction of the epoxides of the general formula magnified image with benzylamine at 40, 50 and 60°C has been examined. The determination of rate constants by variation of X has shown, that in the case of X = S or N no anchimeric acceleration occurred. These results have been approved by product analysis and by synthesis of the possible reaction products. Transition states of the epoxide/benzyl‐amine reaction are discussed by means of the experimentally determined activation energy and activation entropy.
Capricious Stereoselectivities of Alkenylpotassium Formation under Kinetic and Thermodynamic Control Oxygen‐Triggered Configurational Equilibration of an Allyl Type Organometallic Compound
Authors: Stähle Manfred , Hartmann Jürgen , Schlosser Manfred 
Published: December 2004

Abstract(Z)‐1‐Alkylated propenes undergo metallation at an allylic site more rapidly than do their (E)‐isomers, no matter in which configuration the resulting organometallic is thermodynamically more stable. A striking illustration is given by (Z)‐4,4‐dimethyl‐2‐pentenyl potassium which is formed 15 times faster than its (E)‐isomer, although the latter is clearly favored under equilibrium conditions. The configurational reorganization of alkenylpotassium compounds in tetrahydrofuran solution is very slow. At least in one case, however, traces of oxygen efficiently catalyse the Z/E equilibration.
A New Enantioselective Total Synthesis of Natural Vincamineviaan IntramolecularMannichReaction of an Silyl Enol Ether
Authors: Oppolzer Wolfgang , Hauth Hartmut , Pfäffli Paul , Wenger Roland 
Published: December 2004

AbstractNatural Vincamine (1) has been synthesized in an enantioselective manner starting from the ethylpentenal7. In the key step a mixture of the diastereoisomeric racemates,14and15, was directly obtained from the silyl enol ether11and the dihydro‐β‐carboline12by the way of an intramolecularMannichreaction of the intermediate13(Scheme 4). The undesired stereoisomers,14and15b, were recycled to15ausing the related reversibleMannichreaction18 ⇄ 14 + 15, followed by crystallization of the salt from15aand (+)malic acid.15awas converted to natural vincamine (1) in several steps including the known transformation20→1.
Sur l'arǒme de viande de bœuf grillée III. Pyrrolo [1,2‐a]pyrazines, identification et synthèse
Authors: Flament Ivon , Sonnay Philippe , Ohloff Günther 
Published: December 2004

Synthesis of alkylpyrrolo[1,2‐a]pyrazines, roasted meat flavor constituentsSeven alkylpyrrolo[1,2‐a]pyrazines have been identified for the first time in a roasted meat aroma obtained by thermolysis of the hydrosoluble flavor precursors of raw meat. Identification of individual components was done by capillary gas chromatography/mass spectroscopy coupling. The structure of these nitrogen heterocyclic compounds was for some time in doubt because of the similarity of the MS. with those of other diazaindene and diazanaphthalene derivatives such as benzimidazoles, indazoles, cyclopenta [b]pyrazines and dihydroquinoxalines. The structure of these new flavor components was completely elucidated in some cases by interpretation of NMR. spectra, the others being deduced by analogy. Hypotheses are formulated concerning the formation of this skeleton by a non‐enzymatic browning reaction between carbohydrates and amino acids. Four different schemes have been adopted to synthesize substituted isomers selectively.
Synthesis and Polymerization of Trimethyl Bicyclobutane‐1,2,2‐Tricarboxylate
Authors: Hall H. K. , Fischer Walter 
Published: December 2004

AbstractTrimethyl bicyclobutane‐1,2,2‐tricarboxylate (2) was synthesized by a facile five‐step route, beginning with the ferric chloride‐catalyzed addition of chloroform to methyl acrylate to give methyl 2,4,4‐trichlorobutyrate (3). Replacement of the 2‐chloro group by iodide was followed by displacement with dimethyl malonate anion to give trimethyl 4,4‐dichlorobutane‐1,1,2‐tricarboxylate (5a). Thermolysis of the corresponding sodium derivative 5b gave trimethyl cis, trans‐3‐chlorocyclobutane‐1,2,2‐tricarboxylate (6). Closure of the bicyclobutane ring to yield 2 was accomplished by potassium hydride in ether with methanol as catalyst.Bicyclobutane 2 polymerized under free radical initiation with breakage only of the 1,3‐bond. The homopolymers, obtained in moderate yields, were of low molecular weight, probably owing to steric hindrance effects. Copolymerization occurred with vinyl monomers of varying polarity. The copolymers, obtained in moderate yields, had low molecular weights and consisted mostly of the vinyl comonomer units.
Über Pterinchemie. Mitteilung. Die Kristallstruktur von 5,6,7‐Trimethyl‐5,6,7,8‐tetrahydropterindihydrochlorid‐monohydrat
Authors: Bieri Jost H. , Viscontini Max 
Published: December 2004

The crystal structure of 5,6,7‐trimethyl‐5,6,7,8‐tetrahydropterine‐dihydrochloride‐monohydrateThe crystal structure of the title compound has been determined by X‐ray analysis (direct methods) and refined with 947 structure amplitudes to R = 0.026. The crystal system is orthorhombic, space group Pna21, with unit cell dimensions a = 14.081, b = 14.623, c = 6.773 Å. The molecule is protonated at the N(1)‐ and N(5)‐position. The tetrahydropyrazine ring exists in a conformation in which C(6) deviates markedly from the mean plane of the other five atoms. The CH3‐groups at N(5) and C(6) possess a trans configuration with a pseudoaxial and an axial conformation respectively. The CH3‐groups at C(6) and C(7) in return possess the cis configuration, whereby the CH3‐group at C(7) occupies an equatorial conformation.
Utilisation de techniques d'amination réductrice pour la synthèse d'amino‐sucres de différents types. Communication préliminaire
Authors: Tronchet Jean M. J. , Baehler Bruno , Zumwald Jean‐Bernard 
Published: December 2004

Synthesis of amino‐sugars using reductive amination reactions. Preliminary communicationTreatment of aldehydo‐ or keto‐sugars with primary or secondary amines and hydrogen in the presence of a catalyst (Pd/C) gave with good to excellent yields (67–96%) the expected secondary or tertiary amines. Primary amines can be obtained by using benzylamine, a hydrogenolysis taking place during the reaction.
Synthese und Röntgenstruktur von 3‐Hydroxy‐N‐methyl‐hasubanan
Authors: Bruderer Hans , Knopp Dietmar , Daly John J. 
Published: December 2004

Synthesis and X‐ray data of 3‐hydroxy‐N‐methyl‐hasubananA new simple way to synthesis 3‐hydroxy‐N‐methyl‐hasubanan (1c) is described and a single crystal X‐ray structure analysis is presented.
On Metabolic Degradations of Squalene, Lanosterol and Cholesterol in Rat Liver in vivo. Evidence for Recycling of Metabolites for the Synthesis of Isoprene Compounds
Authors: Oswald  , Wiss Verena 
Published: December 2004

Abstract(1) Radioactivity of biosynthetically labeled squalene, injected in tracer amounts in rats is incorporated to about equal parts into cholesterol and component(s) of the fatty acid fraction of the liver. The ubiquinones isolated from the liver are radioactive and show about the same specific radioactivity as the cholesterol. It appears therefore, that the squalene which escapes incorporation into cholesterol is degraded to metabolite(s) suited for the synthesis of isoprene compounds.(2) Radioactivity of injected biosynthetically and chemically labeled cholesterol is traced in the ubiquinones and the squalene of rat liver indicating that a degradation of cholesterol and a recycling of the metabolite(s) occurs.(3) A recycling of metabolite(s) of squalene and of cholesterol can explain the observation that after labeled mevalonate or acetate as precursor, radioactivity can be traced in the squalene of the liver many hours after the injection and maintains a constant value during a period of several hours.(4) Radioactivity of biosynthetically labeled lanosterol is not only incorporated into cholesterol but a considerable part of it into component(s) of the bile acid fraction of the liver. Evidence is obtained that this transformation occurs by circumventing cholesterol as intermediate.
Influence of Insulin and Glucagon on the Cholesterol Synthesis in Rat Liver in vivo. Evidence against a Rate Limiting Function of the HMG‐Coenzyme A Reductase
Authors: Oswald  , Wiss Verena 
Published: December 2004

AbstractPhysiological doses of insulin and glucagon in the range of 0.5–2.5 m unit and 0.05‐2 μg respectively per 100 g body weight stimulate first and inhibit afterwards the cholesterol synthesis from labeled acetate in rat liver in vivo. It could be shown that these effects are not caused by a regulating influence of the HMG‐coenzyme A reductase.
Aromatische sigmatropische Wasserstoffverschiebungen in 2‐Vinyl‐ und 2‐Allylphenolen
Authors: Hansen Hans‐Jürgen 
Published: December 2004

Aromatic Sigmatropic Hydrogen‐Shifts in 2‐Vinyl‐ and 2‐Allyl‐phenolsIt is shown by deuterium labeling experiments that 2‐vinylphenols, on heating at 142,5°, undergo aromatic [1,5]‐H‐shifts whereby o‐quinone methides are formed as intermediates (Scheme 7). Thus, heating of 2‐isopropenylphenol (6) in a D2O/dioxane mixture leads to a rapid deuterium incorporation into the methylidene group of the isopropenyl moiety (Table 1) whereas its methyl group shows only a slow uptake of deuterium. The latter exchange process can be attributed to intermolecular reactions (Scheme 8). The quinone methide intermediates (e.g. 26, Scheme 8) can be regarded as vinyl homologues of alkyl ketones. Therefore, 26 can exchange hydrogen in both methyl groups by an acid‐ and base‐catalysed mechanism. Indeed, when 6 is heated in D2O/pyridine or D2O/CH3COOD/dioxane, an almost statistical incorporation of deuterium into the methylidene and the methyl group of the isopropenyl moiety is observed (Table 3).As a consequence of thermally induced [1,5]‐H‐shifts, 2‐(1′‐propenyl)‐phenols undergo rapid (E,Z) isomerization with first order kinetics on heating above 140° in decane solution. Activation parameters are given in Table 4. The observed primary +++++ H/D isotope effect of 3.3 in the (E,Z) isomerization of phenol 8 is in +++ment with intramolecular H/D‐shifts in the rate determing step (Scheme 9 +++ Table 5). As expected aromatic sigmatropic [1,5]‐H‐shifts in 2‐(1′‐propenyl)‐+++ are much faster than aromatic homosigmatropic [1,5]‐H‐shifts in 2‐(2′‐+++++)phenols (Scheme 1 and Table 6). The structurally comparable phenols +++ (Z)‐10 and (E)/(Z)‐14 (Scheme 3) show k([1,5])/k(homo‐[1,5]) ≈ 2300 at ++++A more detailed discussion in English is given in [1].

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Stoffwechselprodukte von Mikroorganismen 6‐Chlorgenistein und 6,3′‐Dichlorgenistein. 164. Mitteilung
Authors: König W. A. , Krauss C. , Zähner H. 
Published: December 2004

Metabolites from Microorganisms, 6‐Chlorogenistein and 6,3′‐DichlorogenisteinA strain of Streptomyces griseus produced chlorinated metabolites in media containing soybean meal. Two of these metabolites were isolated together with a chlorine free compound which could be identified as the isoflavone genistein (I) by its spectral properties and by comparison with an authentic sample. By NMR. and mass spectroscopy the chlorinated compounds were shown to be 6‐chlorogenistein (II) and 6,3′‐dichlorogenistein (III).The 7‐glucoside of genistein is a constituent of soybean meal; it is hydrolysed and chlorinated by Streptomyces griseus.
Rearrangement of Cephem Bromohydrins to Thiazepine Derivatives
Authors: Petrzilka Theodor , Prasad Kapa K. , Schmid Gerard 
Published: December 2004

AbstractA new rearrangement of cephem bromohydrins 2–5 to thiazepine derivatives 7–8 is described. The structure of the rearrangement product is established by an independent synthesis. The probable mechanism of the above rearrangement is discussed.
Synthèse et propriétés amœbicides d'analogues de l'émétine. Analyse des composés nouveaux en 13C‐RMN. I. (±) Alkyl‐1‐déséthyl‐3‐émétine à jonction B/C cis ou trans
Authors: Buzas André , Cossais Françoise , Finet Jean‐Pierre , Jacquet Jean‐Pierre , Lavielle Gilbert , Cavier Raymond , Platzer Nicole 
Published: December 2004

Synthesis and amoebicid properties of emetin analogs. Analysis of the new compounds by 13C‐NMR. B/C‐cis or trans‐fused (±) 1‐alkyl‐3‐desethyl‐emetin.New 1‐alkyl‐3‐desethyl‐emetines were prepared for pharmacological purposes.The usual emetine synthesis sequence applied to cis‐1‐alkylbenzo [a]quinolizidin‐2‐ones afforded new cis‐1‐alkyl‐3‐desethyl‐emetines.The trans‐fused isomers were also prepared.The relative configuration are determined by 1H‐ and 13C‐NMR. spectra.
The Oxidation of Thebaine with m‐Chloroperbenzoic Acid. Studies in the (+)‐Morphinan Series. III
Authors: Iijima Ikuo , Rice Kenner C. , Brossi Arnold 
Published: December 2004

Zur Oxydation von Thebain mit m‐Chlorperbenzoesäure, IIIDie Oxydation von Thebain (1) mit m‐Chlorperbenzoesäure ist stark abhängig von den gewählten Reaktionsbedingungen. In unserem Fall wird neben 14‐Hydroxy‐codeinon (2) auch das bekannte, mono‐acetylierte Diol 3 erhalten. Die Rückführung von 3 in 2 und die Verknüpfung mit dem bekannten Ketodiol 5, über das bisher nicht beschriebene 8, 14‐Dihydroxydihydrothebain (4) wird gezeigt.