bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthese von diastereo‐ und enantio‐selektiv deuterierten β,ε‐, β,β‐, β,γ‐ und γ,γ‐Carotinen
Authors: Märki Hans Peter , Eugster Conrad Hans 
Published: December 2004

Synthesis of Diastereo‐ and Enantioselectively Deuterated β,ε‐, β,β‐, β,γ‐ and γ,γ‐CarotenesWe describe the synthesis of (1′R, 6′S)‐[16′, 16′, 16′‐2H3]‐β, εcarotene, (1R, 1′R)‐[16, 16, 16, 16′, 16′, 16′‐2H6]‐β, β‐carotene, (1′R, 6′S)‐[16′, 16′, 16′‐2H3]‐γ, γ‐carotene and (1R, 1′R, 6S, 6′S)‐[16, 16, 16, 16′, 16′, 16′‐2H6]‐γ, γ‐carotene by a multistep degradation of (4R, 5S, 10S)‐[18, 18, 18‐2H3]‐didehydroabietane to optically active deuterated β‐, ε‐ and γ‐C11‐endgroups and subsequent building up according to schemes \documentclass{article}\pagestyle{empty}\begin{document}${\rm C}_{11} \to {\rm C}_{14}^{C_{\mathop {26}\limits_ \to }} \to {\rm C}_{40} $\end{document} and C11 → C14; C14+C12+C14→C40.NMR.‐ and chiroptical data allow the identification of the geminal methyl groups in all these compounds. The optical activity of all‐(E)‐[2H6]‐β,β‐carotene, which is solely due to the isotopically different substituent not directly attached to the chiral centres, is demonstrated by a significant CD.‐effect at low temperature. Therefore, if an enzymatic cyclization of [17, 17, 17, 17′, 17′, 17′‐2H6]lycopine can be achieved, the steric course of the cyclization step would be derivable from NMR.‐ and CD.‐spectra with very small samples of the isolated cyclic carotenes. A general scheme for the possible course of the cyclization steps is presented.
Structure‐Activity Relationships of Oxygenated Morphinans. I. 4‐Mono‐ and 3,4‐dimethoxy‐N‐methylmorphinans and ‐N‐methyl‐morphinan‐6‐ones with unusually high antinociceptive potency. Preliminary communication
Authors: Jacobson Arthur E. , Hsu Fu‐Lian , Rozwadowska Maria D. , Schmidhammer Helmut , Atwell Louise , Brossi Arnold , Medzihradsky Fedor 
Published: December 2004

AbstractThe antinociceptive potency and receptor affinity of several optically active aromatic mono‐ and di‐oxygenated N‐methylmorphinans and N‐methylmorphinan‐6‐ones, prepared from natural morphine, were determined. Thus, in order of antinociceptive potency, 4‐methoxy‐N‐methylmorphinan‐6‐one ≈ 3,4‐dimethoxy‐N‐methylmorphinan‐6‐one ≈ 3,4‐dimethoxy‐N‐methylmorphinan > 4‐methoxy‐N‐methylmorphinan ≈ 4‐acetoxy‐N‐methylmorphinan‐6‐one > 4‐acetoxy‐N‐methylmorphinan ≈ 4‐hydroxy‐N‐methylmorphinan‐6‐one ≈ 4‐hydroxy‐N‐methylmorphinan. The 4‐hydroxy compounds were slightly less potent than morphine, and the 4‐methoxy and 3,4‐dimethoxy compounds were found to have three times the potency of morphine. 4‐Methoxy‐N‐methylmorphinan‐6‐one showed an opiate receptor affinity one‐third that of morphine; this is a remarkably high affinity for a non‐phenolic compound.
Bestimmung der Chiralität optisch aktiver Nickelkomplexe mit porphinoidem Ligandysystem
Authors: Meier Kurt , Scheffold Rolf , Engel Peter 
Published: December 2004

Determination of the Chirality of Optically Active Porphine Type Nickel ComplexesThe chirality of (+)‐[1‐methyl‐8 H‐HDP]nickelperchlorate (4) was determined to be (1R) by X‐ray analysis of 7a combined with chemical correlation of the chirality at C(1′) of the 1′‐methyl‐2′‐oxopropoxy side chain of 7a with (−)‐(R)‐2‐methyl‐2,3‐butandiol (9).
Enantioselektive Reaktionen an porphinoiden Nickelkomplexen
Authors: Meier Kurt , Scheffold Rolf 
Published: December 2004

Enantioselective Reactions on Porphine Type Nickel ComplexesThe thermodynamically controlled addition of alcohols to (+)‐(1R)‐[1‐methyl‐8H‐HDP]nickelperchlorate (1; e.e. 92%) yields exclusively the corresponding cis‐1,11‐disubstituted porphinoids. Chemical transformation of functional groups in the alkoxy side‐chain of the chiral addition product followed by acid catalyzed elimination yields the derived alcohols and 1. By this procedure, the following enantioselective transformations were studied: methylation of meso‐2,3‐butandiol (5) to (+)‐(2R,3S)‐3‐methoxy‐2‐butanol (8a; e.e. 87%), diimide reduction of 2‐ethylallyl alcohol (9) to (+)‐(2R)‐2‐methyl‐1‐butanol (12a; e.e. 15%), and hydride reduction of 4‐hydroxy‐2‐butanone (13) to (+)‐(3S)‐1,3‐butandiol (16a; e.e. 20%). Addition of 2,2‐dimethyl‐1,3‐propandiol (17) to 4, followed by esterification of the free hydroxy group with trifluoromethanesulfonic anhydride and solvolysis of the sulfonate 19 yielded a bridged complex with unrearranged alkyl chain for which structure 20 is proposed.
Notiz zum massenspektrometrischen Zerfall monohalogenierter Essigsäuren und Essigsäureester. 36. Mitteilung über massenspektrometrische Untersuchungen
Authors: Lorenzi‐Riatsch Annalaura , Bild Norbert , Hesse Manfred 
Published: December 2004

Note on the Mass Spectral Decomposition of Monohalogenated Acetic Acids and its EstersBesides the well known ester fragmentation reactions two unusual decomposition reactions are observed in the mass spectra of the title compounds, leading to the ions [M‐CO2]+ and [M‐HX]+. The rearrangement reactions involved in the formation of these ions are discussed.
Mechanisms of Diazo Coupling Reactions. Part XXXI. Aminoazo formation in the diazo coupling of N, N‐dimethylaniline and m‐toluidine with p‐methoxybenzenediazonium tetrafluoroborate in acetonitrile
Authors: Penton John R. , Zollinger Heinrich 
Published: December 2004

AbstractIn the title reactions it is shown that aminoazo formation does not occur by direct attack of diazonium ion at C‐atom. Initial attack is at N‐atom, but proton loss from the ωN‐complex formed is relatively slow. Hence, at low amine concentration this rearranges intermolecularly to the aminoazo derivative. At high amine concentration a second method of aminoazo formation can take place involving attack of an amine molecule on the ωN‐complex or on a molecular complex formed between the diazonium ion and the amine. Implication of these proposals for the diazoamino rearrangement are discussed.
Photochemische Reaktionen 122. Mitteilung [1]. Zur vinylogen β‐spaltung von epoxy‐enonen: Photoisomerisierung des 3,4:5,6‐diepoxy‐5,6‐dihydro‐β‐jonons
Authors: Bischofberger Norbert , De Weck Guy , Frei Bruno , Wolf Hans Richard , Jeger Oskar 
Published: December 2004

Vinylogous β‐Cleavage of Epoxy‐enones: Photoisomerization of 3,4: 5,6‐Diepoxy‐5,6‐dihydro‐β‐iononeOn 1n,π*‐excitation (λ>347 nm), 3,4:5,6‐diepoxy‐5,6‐dihydro‐β‐ionone ((E)‐3) shows the typical behaviour of α,β‐unsaturated γ,δ‐epoxy ketones furnishing the (Z)‐enone 3 and by C(γ),O cleavage of the oxirane the dihydrofuryl ketone 10 and the cyclohexanones (E/Z)‐11. However, on 1π,π*‐excitation an unexpected type of transformation is observed: (E)‐3 is isomerized to the four aliphatic triketones 5–8 as the main products. To a smaller extent the allene diketone 9 is formed by a known type of isomerization as well as (Z)‐3.As the starting material for the preparation of (E)‐3, the known epidioxy‐enone (E)‐4 was used. In addition to (E)‐3, (E)‐4 gives the aliphatic triketone 6 and the hydroxyenone 15 by thermal or catalytic isomerization.
Temperaturabhängiger Circulardichroismus von (3S, 3′R)‐ und (3S, 3′ S)‐Adonixanthin
Authors: Noack Klaus 
Published: December 2004

AbstractThe temperature dependent CD. spectra of (3S, 3′R)‐ and (3S, 3′S)‐adonixanthin are compared with those of (3R, 3′R)‐zeaxanthin (1) and (3S, 3′S)‐astaxanthin (2). The room temperature spectra of 1 and 2 are quite similar. On cooling to −180° the CD. of 1 simply intensifies, the CD. of 2 changes sign and becomes also very intense. The room‐temperature CD. of (3S, 3′R)‐adonixanthin (3) resembles closely those of 1 and 2 at room temperature. On cooling, however, it becomes weak and changes strongly its shape. With (3S, 3′S)‐adonixanthin (4) it is the low‐temperature spectrum which resembles that of 2 at low temperature, whereas the room‐temperature spectrum is weak and quite different in shape. These observations can be explained with temperature dependent equilibria where the end groups are twisted out of the plain of the chain thereby conferring chirality to the conjugated system.
Substituted 2‐Phenylnaphthalenes, a New Class of Nematic Liquid Crystals. Preliminary communication
Authors: Lauk Urs , Skrabal Peter , Zollinger Heinrich 
Published: December 2004

AbstractEleven representatives of 6‐n‐alkoxy‐ and 6‐n‐alkanoyloxy‐2‐(4′‐cyanophenyl)‐naphthalenes, a new class of nematogens, are described.
Eine ergiebige Herstellung von 1α,3β‐Dihydroxy‐Δ5‐steroiden durch Reduktion von 1α,2α‐Epoxy‐4,6‐dien‐3‐onen mit Lithium in Ammoniak
Authors: Fürst Andor , Labler Ludvik , Meier Werner 
Published: December 2004

An Efficient Procedure for Preparing 1α,3β‐Dihydroxy‐Δ5‐steroids by Reduction of 1α,2α‐Epoxy‐4,6‐dien‐3‐ones with Lithium in AmmoniaA number of 1α,3β‐dihydroxy‐Δ5‐steroids of the cholestane, (20S)‐20‐methyl‐pregnane (23,24‐dinorcholane), pregnane and androstane series were synthesized from common steroidal precursors. A process originally reported by Barton et al., based on 1,4,6‐trien‐3‐ones as intermediates, was used for the introduction of the 1α‐hydroxyl function. The last step of this process, consisting of lithium/ammonia reduction of 1α,2α‐epoxy‐4,6‐dien‐3‐ones, was found to be crucial and therefore subjected to particular study. A reproducible procedure permitting high‐yield conversion was developed. It consists of first reducing the epoxydienone with an approximately stoichiometric amount of lithium in ammonia to give, after protonation with ammonium chloride, a 1α‐hydroxy‐5‐en‐3‐one. This intermediate is then further reduced by repeated alternating treatment with ammonium chloride and an equivalent amount of lithium.
Etude par des techniques de partition d'énergie des facteurs qui conditionnent l'équilibre conformationnel de propènes disubstitués‐1,3 de configuration E
Authors: Nguyen‐Xuan Tho , Tronchet Jean M. J. , Bill Hans 
Published: December 2004

Effects of the Nature of the C(1) Substituent on the Conformational Equilibrium of (E)‐derivatives of 3‐Methoxypropene: Determination of the origin of the phenomenon using energy partitioning techniquesIntermolecular interactions taking place in the compounds of the general formula (E)‐CH3OCH2CHCHX were analyzed in terms of one‐ and two‐center interaction energies within the framework of SCF ab initio (STO‐3G), Extended Hückel and CNDO methods. The results confirmed the important role of unoccupied orbitals in the stabilization of the different conformers.
Laser‐Induced Fluorescence and Photoelectron‐Photon Coincidence Studies of 3,5‐Octadiyne Cation
Authors: Maier John P. , Misev Liubomir , Thommen Fritz 
Published: December 2004

Abstract3,5‐Octadiyne cation in its lowest excited state has been studied in the gas phase by laser‐induced fluorescence and photoelectron‐photon coincidence techniques. The excitation spectrum of the Ã2″←2A″ transition has been obtained and yields vibrational frequencies of some of the fundamentals for the excited cationic state. The fluorescence quantum yields and lifetimes at selected energies within the Ã2A″ state have been determined from the coincidence measurements. This provides quantitative data for the discussion of the relaxation behaviour of such an excited open‐shell cation.
3‐Triethylsilyloxypentadienyllithium, a Versatile 1,3‐Diene‐ or Vinyl Ketone‐Building Block
Authors: Oppolzer Wolfgang , Snowden Roger L. , Simmons Dana P. 
Published: December 2004

AbstractDeprotonation of the 3‐trialkylsilyloxy‐1,4‐diene 3a and subsequent electrophilic substitution of the non‐isolated 3‐trialkylsilyoxypentadienyllithium 4 gives the α‐ and γ‐products 8 and/or 6 in good yields. Whereas alkylation of 4 proceeds with variable regioselectivity (Table 1) aldehydes and ketones attack preferentially the γ‐position of 4 (Table 2). The desired γ‐products 6 may be directly subjected to inter‐ and intramolecular [4 + 2]‐additions as demonstrated by the reactions 5a ( 6d) → 7 and 6h → 19 (Schemes 4 and 12). Alternatively, smooth fluoride‐promoted silylether‐cleavage 6 → 11 (Scheme 8) provides a convenient approach to substituted vinyl ketones such as to the natural products 11f (Table 3). The stereoselective conversion 6k → 23 (Scheme 13) implies an endo‐selective intramolecular Diels‐Alder addition (26 → 23) and exemplifies the use of 4 as an equivalent of the hypothetical anion IV. Furthermore, some electrophilic substitutions of the hexadienyllithium 15 have been studied (Scheme 10).
Synthesis and Biological Properties of Enkephalin‐like Peptides Containing Carboranylalanine in Place of Phenylalanine
Authors: Schwyzer Robert , Do Kim Quang , Eberle Alex N. , Fauchére Jean‐Luc 
Published: December 2004

AbstractThe syntheses of [D‐Ala2, Car4, Leu5]‐enkephalin, its amide, and of [D‐Ala2, Car4, Met5]‐enkephalin amide are described in detail. The three compounds show pronounced morphine‐like potencies in certain bio‐assays, and were used to investigate the influence of electronic, steric and hydrophobic properties of the side‐chains of amino acids no. 4 and 5 on opioid activity (see [13]).
Bestimmung des Enantiomerenüberschusses von chiralen Ammonium‐Ionen mit Hilfe von Flüssigmembranelektroden
Authors: Bussmann Walter , Simon Wilhelm 
Published: December 2004

AbstractDetermination of the Enantiomeric Excess of Chiral Ammonium long Using Liquid Membrane ElectrodesA cell assembly with two membranes each containing one enantiomer of a chiral ionophore is described. It is suitable for the direct potentiometric determination of the enantiomeric excess of ions. The method is used to determine the enantiomeric excess of ephedronium ions in aqueous solutions.
Alkali Metal/Ammonia Reductions of Ketones Should Be Run in the Presence of Ammonium Ion
Authors: Rautenstrauch Valentin , Willhalm Bruno , Thommen Walter , Burger Ulrich 
Published: December 2004

AbstractReduction of (+)‐[3,3−2H2]camphor ([3,3−2H2]1) with lithium, sodium or potassium in ammonia and a co‐solvent gave; 1) the enolate of [3,3−2H2]1 and the alcoholates of (−)‐[2,3,3−2H3]isoborneol ([2,3,3−2H3] and (+)‐[2,3,3−2H3]borneol ([2,3,3−2H3]3); 2) the alcoholates of [3,3−2H2]2 and [3,3−2H2]3; 3) the dialcoholates of the pinacols [3,3,3′,3′−2H4]4 and [3,3,3′,3′−2H4]5. It is proposed that these are formed from the ketyls [3,3−2H2]1‐ M+, by: 1) disproportionation; 2) H‐atom abstraction from the medium; 3) dimerization. Protonation upon work‐up afforded [endo−32H]1, [2,3,3−2H3]2, [2,3,3−2H3]3,[3,3−2H2]2, [3,3−2H2]3, [3,3,3′,3′−2H4]4 and [3,3,3′,3′−2H4]5. Pinacol [3,3,3′,3′−2H4]5 was the main and pinacol [3,3,3′,3′−2H4]4 a minor product in the reductions with lithium and both were minor products in the reductions with sodium; pinacols were not formed in the reductions with potassium. Parallel reductions of 1, unlabeled, analogously led to 2, 3, 4 and 5, and the ratios 2/3 differed from the ratios ([2,3,3−2H3]2+[3,3−2H2] 2/([2,3,3−2H3]+[3,3−2H2]3) under certain conditions. Different values for these ratios were found in the reductions with each metal, all of which corresponded to low overall diastereoselectivities. Reactions 1 and 3 persisted when the reductions were carried out in ammonia/water/co‐solvent mixtures and the enolate formed via reaction 1 was protonated and the resulting [endo‐3‐2H]1 recycled. Reaction 2 cannot be monitored under these conditions. Reactions 1 and 3, and by inference also reaction 2, were almost completely suppressed when analogous reductions were carried out in the presence of ammonium chloride, [3,3−2H2]2 and [3,3−2H2]3 being obtained almost exclusively, in a 6: 94 ratio. It is proposed that the mechanism outlined in House [1] was dominant when, and only when, ammonium ion was the proton source; it may have competed when water was the proton source.
The Electrochemical Measurement of Rate Constants for the Catalyzed Oxidation and Reduction of Water in microheterogeneous systems
Authors: Sutcliff Emile , Neumann‐Spallart Michael 
Published: December 2004

AbstractThe appearent first‐order rate constants for the oxidation of water by iron tris (bipyridyl) (Fe (bpy)3+3), and reduction of water by methylviologen (MV+) catalyzed by a stabilized RuO2 or Pt‐sol, respectively, were measured. Rate constants for water oxidation at pH 7 of 0.4 s−1 and water reduction at pH 4.7 and pH 1 of up to 460 s−1 for different sols were found.
EPR. Spectroscopic Investigations of Planar Cu (II)‐ and Low‐Spin Co (II)‐Complexes in Nematic Phases and in Single Crystals
Authors: von Zelewsky Alex , Zobrist Markus 
Published: December 2004

AbstractEPR. spectra of planar low‐spin Co (II)‐ and Cu (II)‐complexes were obtained in oriented nematic phases, and compared with single crystal measurements. Unambiguous directional information is only obtained in the case of solute molecules in which the two in‐plane axes are of distinctly different length.
Fragmentation of Homoallylic Alkoxides. Thermolysis of potassium 2‐substituted bicyclo [2.2.2]oct‐5‐en‐2‐alkoxides
Authors: Snowden Roger L. , Schulte‐Elte Karl H. 
Published: December 2004

AbstractThermolysis of the potassium 2‐substituted bicyclo [2.2.2]oct‐5‐en‐2‐alkoxides derived from alcohols 2–17 at 90–120° in hexamethylphosphoric triamide affords unsaturated ketones resulting from allylic bond cleavage. The mechanistic and synthetic aspects of this anionic fragmentation are discussed with reference to the formation of 1‐(3′‐cyclohexenyl)‐2‐alkanones 18–28 via initial heterolytic C(1), C(2)‐bond cleavage in the substrate alkoxide and regioselective, intramolecular protonation of the resultant transient allylic anion.
Synthesis of Phenyl‐ and Benzyl‐Substituted Pyrrolidines and of a Piperidine by Intramolecular C‐Alkylation. Synthons for tricyclic skeletons
Authors: Achini Roland 
Published: December 2004

AbstractThe construction of new or novelly functionalized annulated and bridged tricylic compounds by two consecutive C,C‐bond formations (a and b in la, Scheme 1) is described. In a first step, chloroalkyl‐substituted aminonitriles yielded pyrrolidines 8, 15a, 15b, 23, 25 and piperidine 18 by carbanionic ring closure (Schemes 5, 6, 7 and 8). Subsequent Friedel‐Crafts cyclization transformed the β‐aminonitriles 8, 15a, 15b, and 18 either directly or via their carboxylic acid derivatives to the indeno [1, 2‐c]pyrrole, 2, 5‐methano‐3‐benzazocine, benz [f]isoindoline and 1, 4‐ethano‐2‐benzazapine skeletons 11, 16a, 16b and 21, respectively (Schemes 5, 6 and 7). By classical ring expansion reactions the pyrrolo [3, 4‐c]isoquinoline and benzopyrano‐[3, 4‐c]pyrrole skeletons 28 resp. 31 were obtained from 11 (Scheme 9).
Reaktivität und Elektronenstruktur porphinoider Nickelkomplexe
Authors: Meier Kurt , Scheffold Rolf , Calzaferri Gion 
Published: December 2004

Reactivity and Electronic Structure of Porphine‐type Nickel ComplexesThe electronic structure of the porphine‐type hexaaza[16]annulene‐nickel dikation 1′ as well as its mono‐ and diaddition products 2′ and 3′ (Scheme 2) has been considered by an extended Hückel treatment (SCCC‐MO including charge iteration on the central metal atom). Correlations between calculated data and reactivity of the porphinoid compounds 1, 2 and 3 (Scheme 1) are discussed.
Technische Verfahren zur Synthese von Carotinoiden und verwandten Verbindungen aus 6‐Oxo‐isophoron. III. Ein neues Konzept für die Synthese der enantiomeren Astaxanthine
Authors: Zell Reinhard , Widmer Erich , Lukáč Teodor , Leuenberger Hans Georg Wilhelm , Schönholzer Peter , Broger Emil A. 
Published: December 2004

Technical Procedures for the Synthesis of Carotenoids and Related Compounds from 6‐Oxo‐isophorone. III. A New Concept for the Synthesis of the Enantiomeric AstaxanthinsA new and efficient concept for the total synthesis of (3S, 3'S)‐ and (3R, 3'R)‐astaxanthin (1a and 1c, resp.) in high overall yield and up to 99,2% enantiomeric purity is described. Key intermediates are the (S)‐ and (R)‐acetals 10 and 17, respectively (Scheme 2). These chiral building blocks were synthesized via three different routes: a) functionalization of the enantiomeric 3‐hydroxy‐6‐oxo‐isophorons4) 2 and 11, respectively (Scheme 2); b) optical resolution of 3,4‐dihydroxy‐compound4) 19 (Scheme 3), and c) fermentative reductions of 6‐oxo‐isophorone derivatives (Schemes 4 and 5). ‐ The absolute configurations of the two intermediates 12 and 13 (Scheme 2) have been confirmed by X‐ray analysis. ‐ The final steps leading to the enantiomeric astaxanthins are identical with those described for optically inactive astaxanthin [1].
Technische Verfahren zur Synthese von Carotinoiden und verwandten Verbindungen aus 6‐Oxo‐isophoron. IV. Neues Konzept für die Synthese von (3RS, 3′RS)‐, (3S, 3′S)‐ und (3R, 3′R)‐9,9′‐dicis‐7,8,7′,8′‐Tetradehydroastaxanthin
Authors: Zell Reinhard , Widmer Erich 
Published: December 2004

Technical Procedures for the Synthesis of Carotenoids and Related Compounds from 6‐Oxo‐isophorone. IV. A Novel Concept for the Synthesis of (3RS, 3′RS)‐, (3S, 3′S)‐ and (3R, 3′R)‐9,9′‐dicis‐7,8,7′,8′‐TetradehydroastaxanthinStarting from readily available intermediates of the synthesis of astaxanthin, (3RS, 3′RS)‐, (3R, 3′R)‐ and (3S, 3′S)‐9,9′‐di‐cis‐tetradehydroastaxanthin (1, 1a and 1b, resp.) were synthesized, 1 and 1b for the first time. Key features of this concept are: a) use of the unprotected, acetylenic phosphonium salts 8–12, b) a two‐step synthesis with 47% overall yield, and c) good chemical and optical purity of the end products.
Synthese von optisch aktiven, natürlichen Carotinoiden und strukturell verwandten Naturprodukten. IX. Synthese von (3R)‐Hydroxyechinenon, (3R, 3′R)‐ und (3R, 3′S)‐Adonixanthin, (3R)‐Adonirubin, deren optischen Antipoden und verwandten Verbindungen
Authors: Bernhard Kurt , Englert Gerhard , Mayer Hans , Müller Robert K. , Rüttimann August , Vecchi Max , Widmer Erich , Zell Reinhard 
Published: December 2004

Synthesis of Optically Active Natural Carotenoids and Structurally Related Compounds. IX. Synthesis of (3R)‐Hydroxyechinenone, (3R, 3′R)‐ and (3R, 3′S)‐Adonixanthin, (3R)‐Adonirubin, Their Optical Antipodes and Related CompoundsThe synthesis of racemic and optically active hydroxyechinenone (12–14), adonixanthin (16–19), adonirubin (22–24), meso‐astaxanthin (26) and their corresponding diosphenols 15, 20, 21, 25, 27, 28, and 29) by Wittig reaction is reported, starting from suitable C15‐phosphonium salts and C10‐aldehydes.
Enamines. III. A theoretical and photoelectron spectroscopic study of the molecular and electronic structures of aziridine enamines
Authors: Müller Klaus , Previdoli Felix 
Published: December 2004

AbstractThe photoelectron (PE.) spectra of N‐vinylaziridine (1) and some methyl and ethyl substituted derivatives are discussed in the light of quantum‐chemical model calculations using the PRDDO SCF method. All aziridine enamines are found to exist as equilibrium mixtures of variable compositions, with an enamine‐type conformation (I) generally as the major and a trans‐bisected form (II) as the minor component.
Tasmanin, ein neues Indolalkaloid aus Aristotelia peduncularis (LABILL.) HOOK. F. 181. Mitteilung über organische Naturstoffe
Authors: Kyburz Rolf , Schöpp Emanuel , Bick I. Ralph C. , Hesse Manfred 
Published: December 2004

AbstractAnother representative of this group of alkaloids, aristoteline (2), was also isolated from A. peduncularis. This natural compound has previously been isolated from A. serrata and A. chilensis.