bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low Temperature Thermodynamics. The excess Gibbs function and the volumes of mixing for the system methane + propane at 90.68K
Authors: Stoeckli H. F. , Staveley L. A. K. 
Published: December 2004

AbstractThe excess Gibbs function Ge and the excess volumes of mixing Ve have been measured at the methane triple point (90.68 K) for the system methane+propane. They were compared with McGlashan's recent theory for mixtures of molecules of different sizes.
Die Glykoside der Wurzeln von Xysmalobium dilatatum Weimarck. 2. Mitteilung: Teilstruktur der Dilatoside. Glykoside und Aglykone, 328. Mitteilung
Authors: Meister L. , Stöcklin W. , Reichstein T. 
Published: December 2004

AbstractThe four dilatosides A, B, C and D (ester glycosides isolated from Xysmalobium dilatatum) differ from each other only in the sugar portion. They all contain the same aglycone: 12‐O‐acetyl‐17‐isolineolone (=12‐O‐acetyl‐17‐isodeacyl‐cynanchogenin) (6). Its mass spectrum is discussed. In dilatoside A (1) three molecules of D‐oleandrose (7) are linked to this aglycone, in dilatoside B (2) one D‐canarose (8) and two oleandrose units, in dilatoside C (3) two canarose and three oleandrose, and in dilatoside D (4) probably three canarose and two oleandrose units.
Weitere Cardenolide aus Ch'an Su. Über Krötengifte 37. Mitteilung
Authors: Höriger Niklaus , Živanov Dobrila , Linde Horst H. A. , Meyer Kuno 
Published: December 2004

AbstractFrom the toad venom Ch'an Su digitoxigenin (I), periplogenin (IX), and sarmentogenin (XI) were isolated as well as the two new 14, 15 β‐epoxy‐cardenolides III and VI which — regarding their steroid nucleus — are corresponding to cinobufotalin and marinobufagin, respectively.
Mass Spectrometric Studies of Mono‐ and Di‐Haloacetylenes
Authors: Kloster‐Jensen Else , Pascual C. , Vogt J. 
Published: December 2004

AbstractThe mass spectra of the four monohaloacetylenes X‐CC‐H with X = F, Cl, Br, I and the six dihaloacetylenes X‐CC‐Y with X, Y = Cl, Br, I have been recorded. The dissociation energies of the carbon‐carbon triple bonds of these compounds have been determined from the appearance potentials of the CH+ and CX+ ions. The appearance potentials of the singly‐ and doubly‐charged molecular ions are also reported.
Contribution à l'étude de la mésomérie, IX [1]. Système formé d'un atome à trois électrons et de n atomes à un électron chacun
Authors: Klement O. , Fauchère J. L. 
Published: December 2004

AbstractUne simplification des calculs dans le cadre de la méthode de mésomérie, analogue à celles indiquées dans des mémoires antérieurs [1] et [2], est présentée pour un système à un atome à trois électrons et n atomes à un électron chacun.
Über das Hydrolysegleichgewicht von Phenylbutazon (Butazolidin®)
Authors: Schmid R. W. 
Published: December 2004

AbstractPhenylbutazone (I) forms in aqueous and partially aqueous solution butylmalonic acid mono (N, N′‐diphenylhydrazide) (II) by a reversible reaction. The reaction rate and the position of equilibrium depend on the solvent but practically not on the pH. The temperature dependence is given for several media. Substituents affect the reaction rate when they are in 4‐position but not in 4′‐ or 4″‐position. Based on the kinetic data, a reaction mechanism is proposed. Methods for the analysis of I in mixtures with II are presented. The preparation of II is described.
Equilibres d'ionisation et photoréduction du vanadium(V) dans l'acide sulfurique concentré
Authors: Marcantonatos M. , Piguet R. , Monnier D. 
Published: December 2004

AbstractBy spectrophotometry of dilute solutions of V2O5 in concentrated sulfuric acid VVH2SO4 complexes are shown to convert slowly to VIV monomers. Spectral, kinetic and equilibrium studies on these solutions suggest that this conversion involves a photoreduction of VV to VIV dimeric species.
Vibrations de valence CH dans les hydrocarbures et les halogénures de butyle
Authors: Avanessoff M. , Gäumann T. 
Published: December 2004

AbstractThe valence vibrations CH and CD of a number of alkanes and of (CH3)3CX are studied using compounds deuterated in specific positions. For the methyl and the methylene groups an experimental model of group frequencies is proposed, which allows some general conclusions to be drawn concerning the assignation of the frequencies. The methyl group always shows a Fermi resonance between νs and 2δas in the region of 2930–2870 cm−1. In consequence the unperturbed νsCH3 frequency may be situated at ∽2915 cm−1 and the absence of a coupling with other groups can be checked. The vibrations of the methylene group adjacent to a methyl group have higher frequencies than those of CH2 groups further removed. The coupling of the methylene group with other groups is always strong and may amount to 10 cm−1. For a chain of methylene groups, the coupling is the larger the longer the chain; being relatively small for symmetrical modes (∽3 cm−1) for the antisymmetric mode. A correlation is found between protonated and deuterated groups which leads to isotope effects comparing well with recorded values.
Energy Profiles for Ring Formation‐ and Ring Opening‐Processes in the cis‐Stilbene‐4a,4b‐Dihydrophenanthrene System. An example of the feasibility of a process forbidden by the rules of orbital symmetry conservation
Authors: Muszkat K. A. , Schmidt W. 
Published: December 2004

AbstractAn Extended Hückel MO treatment of the system cis‐stilbene (I)‐4a, 4b‐dihydrophenanthrene (II) indicates that the concerted photocyclisation is a conrotatory process of the first excited electronic state. The activation energies for the photocyclisation and for the thermal ring opening and the ground state energy difference between I and II, as predicted by the present calculation, are in good agreement with the experimental findings. The observed effects of substituents on the photocyclisation quantum yields are satisfactorily accounted for by a general qualitative treatment and thus indicate that the photocyclisation takes place in the first excited state.
Beiträge zur Chemie der 4‐Hydroxyindol‐Verbindungen 10. Mitteilung über synthetische indolverbindungen [1]
Authors: Seemann F. , Wiskott E. , Niklaus P. , Troxler F. 
Published: December 2004

AbstractCatalytic hydrogenation of 4‐benzyloxyindoles does not stop at the hydroxyindole stage, but slowly leads to the 4,5,6,7‐tetrahydro‐4‐ox‐indoles 3. Some procedures for the selective preparation of 4‐hydroxyindoles 2 are described. When 4‐benzyloxy‐3‐(1‐hydroxyimino‐ethyl)‐indole (4c) is warmed with trifluoroacetic acid, cleavage of the ether results as well as partial benzylation of the free hydroxyindole in the position 5 (5a, 5b); no Beckmann rearrangement is observed. Esters of 4‐benzyloxy‐indole‐2‐carboxylic acid are formylated with POCl3/dimethylformamide in the 7‐position to give 7a; in the corresponding dimethylamide, on the other hand, the formyl group enters the 3‐position to give 8. Both 4‐ and 7‐hydroxyindole are oxidized with Frémy's salt to the 4, 7‐quinone 13; on reduction this yields 4, 7‐dihydroxyindole 14, which is tautomerized by base‐catalysis to 5, 6‐dihydro‐4, 7‐dioxo‐indole 15. The course of the etherification of 4‐hydroxyindoles with epichlorohydrin and related compounds is described, and the resulting side‐chains are characterized by their NMR. spectra.
Weitere Untersuchungen über den Mechanismus der reduktiven Spaltung von Azoverbindungen
Authors: Schellenberġ M. , Mollet H. 
Published: December 2004

AbstractThe experimental results of our earlier investigation of the azodye bleach mechanism are interpreted in a revised manner. The reductive cleavage of methylorange by a dihydroquinoxaline proceeds in two steps. In the medium pH‐range the first step (production of the hydrazo derivative) is slower (and not faster, as considered before) than the second (reductive splitting of the hydrazo derivative). In strongly acid solution this relation is reversed.The rate of disproportionation of the hydrazo derivative of methylorange is proportional to the concentration of the protonated hydrazo compound. For this reaction a two step mechanism is proposed in which a molecule of hydrazo compound is cleaved in a rate determining first step to an oxidizing particle and an amine molecule. In the following fast reaction the oxidizing intermediate attacks a second hydrazo molecule yielding methylorange and a further amine molecule. Based on this reaction sequence an azodye bleach mechanism is formulated which is able to explain the kinetics of the reductive cleavage of methylorange by a 1, 4‐dihydroquinoxaline at any pH value.The azodye bleach mechanism is much more complex if the 1,4‐dihydroquinoxaline used is able to form a radical or to tautomerize. The resulting reaction kinetics are discussed.
Synthesen in der Carotinoid‐Reihe 23. Mitteilung Ein Beitrag zur Chromsäure‐Oxydation von Polyenen
Authors: Schwieter U. , Arnold W. , Oberhänsli W. E. , Rigassi N. , Vetter W. 
Published: December 2004

AbstractChromic acid oxidation of polyenes with terminal β‐ionylidene groups has been studied. A number of hitherto unknown and unexpected oxidation products has been isolated. A mechanism for these oxidations is discussed.
Synthese Aldosteron‐ähnlicher Corticosteroide. Racemisches 11‐Dehydroaldosteron (rac.‐18‐Oxo‐11‐dehydrocorticosteron) Über Steroide, 223. Mitteilung
Authors: Schmidlin J. 
Published: December 2004

AbstractRacemic 11‐dehydroaldosterone (rac.‐18‐oxo‐11‐dehydrocorticosterone) is prepared starting from the 3, 3; 20, 20‐bisethylene acetal of the racemic 3, 20‐dioxo‐11β, 21‐dihydroxy‐Δ‐pregnene‐18‐oic acid‐(18 → 11β)‐lactone, an intermediate obtained previously in the first total synthesis of aldosterone. A cyclic 18(21)‐hemiacetal structure is deduced for the new corticosteroid from spectroscopic and chemical evidence.
Abschätzung der Alkali‐ und Erdalkali‐Ionenselektivität von elektrisch neutralen träger‐antibiotica («carrier‐antibiotica») und modellverbindungen
Authors: Morf W. E. , Simon W. 
Published: December 2004

AbstractUsing model calculations, the influence of coordination number, properties of ligand groups, dimension of the ligand, steric interactions, and solvent on the complexation of alkali‐ and alkaline earth metal cations by electrically neutral ligands (carrier antibiotics, model compounds) is discussed. Information is given on the molecular parameters needed to achieve a given ion selectivity in view of the use of such ligands as carriers in ion selective membranes.
Steroide und Sexualhormone 243. Mitteilung [1] die partialsynthese von 3‐o‐methyl‐20ξ‐7, 8‐dihydrobatrachotoxinin A
Authors: Graf W. , Gössinger Frl. E. , Imhof R. , Wehrli H. 
Published: December 2004

AbstractThe synthesis of 3‐O‐methyl‐20ξ‐7, 8‐dihydrobatrachotoxinin A (12) is described.
Über das Lipoxygenase‐«Lipoperoxidase»‐System in Cerealien: I. Untersuchung der reaktionsprodukte
Authors: Heimann W. , Schreier P. 
Published: December 2004

AbstractZusammenfassung. Nach Inkubation der durch Soja‐Lipoxygenase (E.C.1.13.1.13.) gebildeten Linolsäurehydroperoxide (LHPO) mit einem Hafer‐Acetontrockenpulver treten 13‐Hydroxy‐cis‐9, trans‐11‐octadecadiensäure und 9‐Hydroxy‐trans‐10, cis‐12‐octadecadiensäure auf. Durch Einsatz von [14C]‐LHPO wird nachgewiesen, dass es sich um Umsetzungsprodukte der LHPO handelt. Nach Hitzeinaktivierung bleibt die Umsetzung aus. Die Verbindungen wurden nach Veresterung, katalytischer Hydrierung und Oxydation als 13‐Oxo‐ bzw. 9‐Oxo‐stearinsäure‐methylester massenspektrometrisch identifiziert. Trennung und Reinigung erfolgten jeweils mittels präparativer Schichtchromatographie unter spektroskopischer Kontrolle (UV., IR.). Auf Grund der Ergebnisse kann auf die Beteiligung einer Peroxidase am enzymatischen LHPO‐Abbau in Hafer geschlossen werden. Die Beteiligung von Lipoxygenase und Peroxidase an der Biosynthese cis‐trans‐konjugierter Hydroxyfettsäuren wird diskutiert.
Heterogenität der Drosophila‐Aldolase und Hybridisierung mit Säugeraldolase 20. Arbeit über aldolasen
Authors: Brenner‐Holzach O. , Leuthardt F. 
Published: December 2004

Abstract–1. FDP aldolase from pupae of Drosophila melanogaster is shown by the following findings to be a tetrameric molecule with two non‐identical subunits: (a) Disc electrophoresis on polyacrylamide gel in the presence of sodium dodecylsulfate yields a subunit molecular weight of 40000 (equal to that of rabbit muscle aldolase). (b) Hybridisations of drosophila aldolase with type C aldolase from rabbit and calf brain lead to a five‐membered set of isoenzymes.2. The non‐identity of the subunits is suggested by the behaviour on isoelectro focussing. While rabbit muscle aldolase and human liver aldolase show five isoenzymes (hybrids from the non‐identical subunits), drosophila aldolase can be separated into three peaks only. This result may be interpreted in two ways: (a) The isoenzymes α4 and α3α′ are not separated from each other in the pH range 5‐‐8, neither are αα′3 and α′4. Or (b) α2 and α′2 are not split under the condition of isoelectro focussing and therefore 3 isoenzymes α4, α2α′2, and α′4 are obtained only.(3) Isoenzyme I (supposedly mainly α4) and isoenzyme III (supposedly mainly α′4) are identical in the following respects: Michaelis constant, pH profile, FDP/F‐1‐P activity ratio, inactivation by carboxypeptidase A, disc electrophoresis on polaycrylamide and molecular weight. The only difference found between isoenzyme I and III is the specific activity: Isoenzyme I is nearly twice as active as isoenzyme III.4. The fact that hybridisation between drosophila aldolase and type C aldolase from rabbit and calf brain yields a set of isoenzymes proves that interspecies hybridisation is possible between FDP aldolases from vertebrates and invertebrates. FDP aldolases from vertebrates and invertebrates seem to be homologous enzymes. Our results suggest that the conformation of aldolases remained relatively unchanged during evolution.
Photolyse von indazolen, benzisoxazolen und anthranilen in saurer Lösung Vorläufige Mitteilung
Authors: Georgarakis [2] M. , Doppler [3] T. H. , Märky M. , Hansen H.‐J. , Schmid H. 
Published: December 2004

AbstractIndazoles and anthranils on irradiation with a mercury high‐pressure lamp in acidic solution (H2SO4/H2O or H2SO4/CH3OH) yield 2‐amino‐5‐hydroxy(or methoxy)‐benzaldehydes (acetophenones, respectively) as major products and 2‐amino‐3‐hydroxy (or methoxy)‐benzaldehydes (acetophenones, respectively) as minor products. Photolysis of benzisoxazoles in conc. sulfuric acid results in the formation of 2,5‐and 2, 3‐dihydroxybenzaldehydes (acetophenones, respectively). 5‐Methylindazoles form on irradiation in diluted sulfuric acid 2‐amino‐5‐methyl‐benzaldehydes.
Comment on the Chirality and Cotton Effects of Cyclic α‐Diketones: Revision of recent conformational assignments
Authors: Burgstahler Albert W. , Naik Nandkishor C. 
Published: December 2004

AbstractA recent proposal [1] correlating the Cotton effects and dione chirality of various cyclic α‐diketones according to a skewed glyoxal model is held to require revision in the light of overriding evidence from molecular models and the effects expected from substituent chirality contributions.
Die Umwandlung von Penicillinen in Cephalosporine. Modifikationen von Antibiotika, 3. Mitteilung
Authors: Heusler K. 
Published: December 2004

AbstractA new method for the degradation of the thiazolidine ring in penicillins is described. Penicillin V (8a), penicillin G (8b) and 6‐t‐butoxycarbonylaminopenicillanic acid (33) (BOC‐6‐APA) were converted via their acylazides and isocyanates (10 and 34) into 2,2,2‐trichloroethyl urethanes (11 and 35). Reductive removal of the trichloroethoxycarbonyl groups in an aqueous medium gave the 3‐hydroxy‐penam‐derivatives 13 and 36. The structure and various reactions of these carbinolamides are discussed in detail. An oxidative radical fragmentation (using lead tetraacylates and light) followed by thermal treatment transformed the 3‐hydroxy‐penam‐derivatives into the N‐formyl‐β‐lactam‐thio‐enolethers 27 and 37 in which the formyl group could be replaced by hydrogen. Reactions of the β‐lactam and thio‐enolether functions are described.The BOC‐derivative 37 can be transformed into the isomeric compound 3, an intermediate in Woodward's total synthesis of cephalosporins.
Neue β‐Lactamsysteme aus Penicillinen. Modifikationen von Antibiotika, 5. Mitteilung [1]
Authors: Fechtig B. , Bickel H. , Heusler K. 
Published: December 2004

Abstract3‐Isopropyl‐4‐thia‐2,6‐diazabicyclo[3.2.0]heptan‐7‐on (8), a potential intermediate for the synthesis of new β‐lactam antibiotics [5], was prepared from the urethanes 7a and 9 by reduction with zinc/acetic acid. The cyclic Schiff base 10, which constitutes an intermediate in this reaction, was prepared by reduction of 9 with CrCl2 and was further reduced to 8 with zinc/acetic acid.
Myrochromanol und Myrochromanon, zwei weitere Metaboliten von Myrothecium roridum Tode ex Fr. Verrucarine und Roridine, 25. Mitt.
Authors: Tamm Ch. , Böhner B. , Zürcher W. 
Published: December 2004

AbstractFrom cultures of Myrothecium roridum Tode ex Fr. myrochromanol (1) and myrochromanone (3), two new substituted chromanes, have been isolated. Their structures as 2‐(1‐propenyl)‐4‐hydroxy‐6‐methyl‐chromane and 2‐(1‐propenyl)‐4‐oxo‐6‐methyl‐chromane respectively, have been determined using spectroscopic techniques and by degradation to 2‐hydroxy‐5‐methylbenzoic acid (6). The stereochemistry of 1 and 2 is deduced by NMR., CD. and by partial resolution ( Horeau method).
Massenspektrometrische Untersuchungen von Naturprodukten; Cardenolide
Authors: Brown Peter , Brüschweiler Fred , Pettit Georg R. 
Published: December 2004

AbstractThe mass spectrometry of cardenolides is briefly reviewed. Recent developments in the characterization of the cardiac glycosides by a combination of electron impact and field ionization methods are discussed, with emphasis on the information obtained regarding the sequence of monosaccharide residues in the case of oligosaccharide glycosides. Recent efforts to understand the detailed fragmentation behaviour of cardenolide aglycones in terms of their structure and substitution pattern are also discussed.
1‐Substituierte Cycloheptatrienverbindungen
Authors: von Bredow K. , Helferich G. , Weis C. D. 
Published: December 2004

AbstractCycloheptatriene reacts with acrylic esters, in the presence of catalytic amounts of tricarbonyl‐triphenylphosphine‐nickel, to yield a mixture of α‐cycloheptatrienyl‐propionic acid esters (2a) substituted in various positions. Methacrylic acid ester yields likewise α‐cycloheptatrienyl‐isobutyric acid ester (3a). Both types of ester mixtures undergo thermal isomerizations by 1,5‐hydrogen shifts to give mixtures which contain predominantly the (C‐1)‐substituted cycloheptatrienyl‐carboxylic acid esters (2a, 3a). Pure α‐(1‐cycloheptatrienyl) derivatives can be prepared from 2a and 3a. A detailed NMR. study of the ester mixtures before and after thermal isomerization shows the proportions of the various isomers in the mixture. The mechanism of the formation of 2a and 3a is explained in terms of a catalysed ene‐reaction of the primary formed 7‐substituted cycloheptatriene derivatives with subsequent consecutive 1,5‐hydrogen shifts.
Composés d'addition des halogénures de niobium(V) et de tantale(V). V. Stabilité relative des composés des chlorures avec quelques oxydes et sulfures organiques
Authors: Merbach A. , Bünzli J. C. 
Published: December 2004

AbstractThe adducts of niobium(V) and tantalum(V) chlorides with some aliphatic and cyclic oxides and sulfides, studied by NMR. spectroscopy in CHCl3, are found to have 1:1 stoechiometry, at room temperature and lower. In the thioxane complex TaCl5 · C4H8OS two species are present with the ligand coordinated by the sulfur atom or by the oxygen atom, respectively, in a proportion which has been determined. The thioxane adduct of niobium(V) chloride, however, is preferentially coordinated by the sulfur atom. There is also evidence for the species 2MCl5 · C4H8OS. The relative basicity of each donor atom in dioxane, thioxane and dithiane is calculated and discussed. In contrast to the nitrile adducts, whose stability was found earlier to be controlled by inductive factors, the steric factors are more important for the ether and sulfide adducts: MCl5 · Me2X is more stable than the corresponding MCl5 · Et2X (M = Nb, Ta; X = O, S). Both niobium(V) and tantalum(V) chlorides have a soft behaviour, but NbCl5 is a weaker Lewis acid than TaCl5 and shows also a softer behaviour.
Sigmatropic Reactions in Carbanions. I. The 5, 6‐dihydro‐2H‐pyran‐2‐ide cyclopropyl‐enolate rearrangement
Authors: Rautenstrauch V. 
Published: December 2004

AbstractLithiation of 5,6‐dihydro‐2H‐pyran (7) gives a mixture of dihydropyranyllithiums 14 and 2. 14 rearranges to 2, and 2 in turn undergoes a [1,4] sigmatropic shift to give the lithium cyclopropyl‐enolate 3. Lithiation of nerol oxide 6 gives the lithio derivative 24, which likewise undergoes [1,4] shifts to give cyclopropyl‐enolates 28 and 29.
Über Pyrrolizidinchemie. 11. Mitteilung [1]. Totalsynthese von (±)‐Platynecin
Authors: Viscontini M. , Buzek H. 
Published: December 2004

Abstract1‐Methoxycarbonyl‐7‐oxo‐6,7‐dihydro‐5H‐pyrrolizin (I) bildet durch katalytische Hydrierung vorwiegend das (±)‐Lacton (II), dessen Konfiguration eindeutig bestimmt wurde. Reduktion mittels LiAlH4 wandelt dieses Lacton in (±)‐Platynecin (III) um, ohne Berührung der chiralen Zentren der Molekel. Die chemischen und physikalisch‐chemischen Eigenschaften des synthetisch erhaltenen Razemates stimmen mit jenen des natürlichen (−)‐Platynecins überein.
Photoinduced reactions of aryl‐2H‐azirines with carbonyl compounds. Preliminary communication
Authors: Giezendanner H. , Märky M. , Jackson B. , Hansen H.‐J. , Schmid H. 
Published: December 2004

AbstractIrradiation of 3‐phenyl‐(4), 2‐methyl‐3‐phenyl‐(8), and 2,3‐diphenyl‐2H‐azirine (10), in benzene solution in the presence of aldehydes, yields the corresponding aryl‐3‐oxazolines. Photochemical reaction of 4 and 10 with carbon dioxide leads to the formation of 4‐phenyl‐ (15) and 2,4‐diphenyl‐3‐oxazolin‐5‐one (16), respectively.
Zur Photodimerisierung von 3‐Phenyl‐2H‐azirinen. Vorläufige Mitteilung
Authors: Gakis N. , Märky M. , Hansen H.‐J. , Schmid H. 
Published: December 2004

AbstractIrradiation of 3‐phenyl‐2H‐azirine (2) in benzene solution with a high‐pressure mercury lamp yields 4,5‐diphenyl‐1,3‐diazabicyclo[3,1,0]hex‐3‐ene (4) and not 3‐phenylimino‐4‐phenyl‐1‐azabicyclo[2,1,0]pentane (1), as had been reported previously by others [2]. 2‐Methyl‐3‐phenyl‐2H‐azirine (3) yields on irradiation a 2:1 mixture of 2‐exo, 6‐exo‐ and 2‐exdo, 6‐exo‐dimethyl‐4,5‐diphenyl‐1,3‐diazabicyclo[3,1,0]hex‐3‐ene (2‐exo,6‐exo‐ and 2‐endo, 6‐exo‐5). Irradiation of 2,3‐diphenyl‐2H‐azirine (8) leads to the formation of 2,4,5‐triphenyl‐imidazole (9) and tetra‐phenylpyrazine (10). The suggested reaction path for the generation of 9 and 10 is shown in Scheme 2.
The Natural Occurrence of the Campholenyl Skeleton, Another «Non‐isoprenoid» Monoterpene System
Authors: Thomas Alan F. 
Published: December 2004

AbstractIn the essential oil of Juniperus communis L. (fruit), campholenic aldehyde and its epoxide have been identified, together with the corresponding alcohol and its acetate. This is the first time the natural occurence of 2‐(2,2,3‐trimethylcyclopent‐3‐en‐1‐yl)‐ethyl system is reported.
Circulardichroismus einiger A‐nor‐Steroide und verwandter Verbindungen
Authors: Snatzke G. , Lábler L. , Tamm Ch. 
Published: December 2004

AbstractThe Circular Dichroism (CD.) of several saturated and conjugated keto‐A‐nor‐steroids follows the known rules. Homochiral α,β‐epoxy‐cyclopentanones and ‐cyclohexanones give the same sign of the Cotton effect within the R‐band, whereas the K‐band CD. of the former has opposite sign to that at 300 nm. More examples for the application of the rule for the determination of the CD. of non‐coplanar conjugated lactones as well as α,β‐epoxy‐lactones are presented.