bluuebunny/crossref_metadata_2025_split huggingface dataset:
Über Umwandlungen der Iboga‐Alkaloide Voacangin und Conopharyngin 154. Mitteilung über Alkaloide
Authors: Morita Yutaka , Savaskan Sabri , Jaeggi Knut A. , Hesse Manfred , Renner Ulrich , Schmid Hans 
Published: December 2004

AbstractThe reduction products voacanginol (3) and conopharynginol (4), obtained from the indole alkaloids voacangine (1) and conopharyngine (2) respectively, gave, by the treatment of their tosylates 5 und 6 with triethylamine, two fragmentation products, voaenamine (7) (70–80%) and conoenamine (8) (25–45%) respectively (Scheme 1). The structures of 7 and 8 were derived from spectroscopic evidence and some chemical transformations.Conopharynginol tosylate (6) gave with tertiary base, besides 8, the quaternary aziridinium salt 12 (58%) (Scheme 3). This salt could undergo nucleophilic attack, giving compounds of the A‐series with a C‐homo‐conopharyngine skeleton (due to attack at C(18)) and compounds of the B‐series with a spiro‐centre (due to attack at carbon(5)) (Scheme 3). The structures of these compounds were elucidated using D‐incorporation experiments, 1H‐ and 13C‐NMR. and mass spectra. On heating to 230°, acetylated spiroalcohol 22 was converted, probably via the ion pair 23, into the base 16, which on catalytic reduction gave 13, a member of the A‐series.The reactions mentioned above constitute interesting skeletal isomerisations of the conopharyngine skeleton.
Synthetische Juvenilhormone 2. Mitteilung.p‐Substituierte 2‐Methyl‐3‐phenyl‐propen(1)‐carbonsäurederivate
Authors: Franke Albrecht , Mattern Günter , Traber Walter 
Published: December 2004

AbstractIn the second communication the synthesis of para‐substituted 2‐methyl‐3‐phenylpropen(1)‐carboxylic acid derivatives is described: Phenylacetone compounds are formed by decarboxylation of a glycidicester; these react according to theWadsworth‐Emmons(Wittig‐Horner)‐reaction with the corresponding phosphonates to the title compounds. NMR. data show the formation of the steric isomers of 3‐Phenyl‐2‐methyl‐propen‐1‐ and 3‐Phenyl‐2‐methylpropen‐2‐carboxylic acid derivatives.
Recherches dans la série de la quinoléine: Préparation et oxydation du chlorhydrate de (1‐quinoléinio)acétate
Authors: Mottier M. 
Published: December 2004

AbstractReaction of quinoline with chloroacetic acid yields N‐carboxymethyl‐quinolinium chloride (1) (75%), which is oxidised by K3Fe(CN)6in the presence of a base to N‐carboxymethyl‐2‐quinolone (2) (70%). If 2 is heated in pure form at 300°, 1,3‐Bis(2‐quinolon‐1‐yl)acetone (4) (43%) is obtained; the expected N‐methyl‐2‐quinolone (5) is formed by decarboxylation of2in benzyl benzoate at 275° (34%).
Preparation and Some Properties of Maleimido Acids and maleoyl derivatives of peptides
Authors: Keller Oskar , Rudinger Josef 
Published: December 2004

AbstractN‐Alkoxycarbonylmaleimides 3 have been prepared and used to convert amino acids to maleimido acids (6–8) in aqueous solution. The carboxyl group of maleimido acids can be activated for amide or peptide synthesis (e.g., in the N‐succinimidyl esters 10); t‐butyl‐based protecting groups can be cleaved without damage to the maleimide moiety. Peptides carrying maleimide groups are accessible either from the maleimido acids (e.g., 11b, 15) or by direct maleoylation (e.g., 16b). The maleoyl group can be cleaved off by successive mild alkaline and acid hydrolysis or by hydrazinolysis. The reactivity of maleimides toward thiol groups suggests the use of maleimido acids and maleoylpeptides for preparing a wide range of conjugates of biochemical interest.
Steroids. Part I. Selective Hydrogenation of Ergosterol and its Acetate
Authors: Tadros Wadie , Boulos Adel Louis 
Published: December 2004

AbstractSelective hydrogenation of ergosterol or its acetate in solution in different solvents over Raney nickel to give 5α‐ergosta‐7,22‐dien‐3β‐ol or its acetate can be controlled by the addition of paraformaldehyde, acetaldehyde, benzaldehyde, 4‐dimethylaminobenzaldehyde, and dimethylaniline, the latter 2 giving the best yield. When using pure solvents 5α‐ergost‐7‐en‐3β‐ol or its acetate can be obtained in almost quantitative yield.
Ab initio SCF Calculation of the Fluoronium Ion: Geometry, electronic structure and vibrational constants
Authors: Wild Urs P. , Ha Tae‐Kyu , Raggio Guido A. , Keller Hans U. , Brunner Peter O. 
Published: December 2004

AbstractAn ab initio SCF calculation of 42 points of the energy hypersurface of the fluoronium ion is presented using a contracted F(5s/3p), H(2s) gaussian basis set. In its equilibrium structure a bond length of 1.812 a.u. and a HFH bond angle of 127.2° are predicted. The calculated vibrational frequencies for H2F+, HDF+, and D2F+ are in good agreement with the experimental data.
Photochemische Cycloadditionen von 3‐Phenyl‐2H‐azirinen mit Benzoyl‐, Äthoxycarbonyl‐ und Vinylphosphonaten 34. Mitteilung über Photoreaktionen
Authors: Gakis Nikolas , Heimgartner Heinz , Schmid Hans 
Published: December 2004

AbstractThe irradiation of the 3‐phenyl‐2H‐azirines 1a–c in the presence of diethyl benzoylphosphonate (8) in cyclonexane solution, using a mercury high pressure lamp (pyrex filter), yields the diethyl (4, 5‐diphenyl‐3‐oxazolin‐5‐yl)‐phosphonates 9a–c (Scheme 3). In the case of 1b a mixture of two diastereomeric 3‐oxazolines, resulting from a regiospecific but non‐stereospecific cycloaddition of the benzonitrile‐benzylide dipole 2b to the carbonyl group of the phosphonate 8, was isolated.Benzonitrile‐isopropylide (2a), generated from 2,2‐dimethyl‐3‐phenyl‐2H‐azirine (1a), undergoes a cycloaddition reaction to the ester‐carbonyl group of diethyl ethoxycarbonylphosphonate (15) with the same regiospecificity to give the 3‐oxazoline derivative 16 (Scheme 5).The azirines 1a–c, on irradiation in benzene in the presence of diethyl vinylphosphonate (17) give non‐regiospecifically the Δ1‐pyrrolines 13a–c and 14a–c (Scheme 6).
Herstellung und photochemisches Verhalten von 2‐O‐und 2‐N‐substituierten 1,3‐Cyclohexadiencarbonsäurenitrilen
Authors: Margaretha Paul 
Published: December 2004

Abstract2‐Methoxy‐ and 2–1′‐azetidino‐5,5‐dimethyl‐1,3‐cyclohexadienoic acid nitrile are prepared from the newly synthetized compound 2‐oxo‐5, 5‐dimethyl‐3‐cyclohexenoic acid nitrile. Irradiation of these cyclic dienes leads to the formation of the corresponding open‐chain trienoic acid nitriles.
Additionen von 2,2‐Dimethyl‐3‐dimethylamino‐2H‐azirin an 2‐Formyl‐cycloalkanone und Sulfinsäuren
Authors: Chandrasekhar B. Parthasarathi , Schmid Ursula , Schmid Rudolf , Heimgartner Heinz , Schmid Hans 
Published: December 2004

Abstract2,2‐Dimethyl‐3‐dimethylamino‐2H‐azirine (1) reacts with the formyl‐cycloalkanones 4–8 in boiling benzene to give the 1:1 adducts 13–17 in 60–99% yield (Table). These adducts are N′‐[(2‐oxo‐cycloalkylidene)‐methyl] derivatives of 2‐amino‐N, N‐dimethylisobutyramide. The reaction mechanism (Scheme 6) is analogous to the mechanism of the reaction of 1 with carboxylic acids and cyclic enolisable 1,3‐diketones [1].Sulfinic acids and 1 undergo a similar reaction at −15° to yield 2‐sulfinamido‐N, N‐dimethylisobutyramides (Schemes 4 and 7), while sulfonic acids and the azirine 1 lead to a dimeric salt of type 20, which with sodium hydroxide gives the dihydropyrazine 21 (Scheme 5).
1,1‐Dimethyl‐1‐silacyclohexa‐2,4‐dien‐tricarbonyleisen Vorläufige Mitteilung
Authors: Fink Walter 
Published: December 2004

Abstract1,1‐Dimethyl‐2,3,4,5‐tetraphenyl‐1‐silacyclohexa‐2,4‐diene is isomerized by iron pentacarbonyl to 1,1‐dimethyl‐2,3,4,5‐tetraphenyl‐1‐silacyclohexa‐2,5‐diene. However, iron pentacarbonyl with 1,1‐dimethyl‐1‐sila‐cyclohexa‐2,4‐diene yields 1,1‐dimethyl‐1‐silacyclohexa‐2,4‐diene‐tricarbonyl‐iron.
Isolierung und Charakterisierung von nativer nuklearer Desoxyribonukleinsäure aus Tabakblättern
Authors: Temperli A. , Künsch U. , Türler H. 
Published: December 2004

AbstractTobacco nuclear DNA (nDNA) was isolated from tobacco leaf nuclei which were prepared according to our previously published procedure [8]. The nDNA was characterized by base analysis, absorption spectrophotometry, analytical CsCl density gradient equilibrium centrifugation and by its melting behaviour. The results show that the isolated tobacco nDNA is native, high molecular weight DNA, which is free of detectable amounts of chloroplast DNA, RNA, protein and polysaccharides. From its melting behaviour it was concluded that tobacco nDNA can be placed close to calf thymus DNA with respect to intramolecular heterogeneity. Experiments on the partial and complete denaturation of tobacco nDNA and its ability to renature are also reported.
A Classical Synthesis of the Collagen‐like Peptides with the Sequence Z(GlyProPro)nOBut and their characterization with circular dichroism and ultracentrifugation
Authors: Bruckner Peter , Rutschmann Beatrice , Engel Jürgen , Rothe Manfred 
Published: December 2004

AbstractOligopeptides with the sequence Z(GlyProPro)nOBut (n = 3–7) were synthesized along a clasical pathway. Generally long fragments were condensed in order to allow an easy separation of the products from the reactants. It is established by molecular weight determination and measurements of circular dichroism that the peptides form the collagen‐like triple helix in methanol and that they assume the random coil conformation in dilute acetic acid. The circular dichroism spectra agree reasonably well with the corresponding spectra for (ProProGly)10 which was obtained by solid phase synthesis in another laboratory.
Steroide und Sexualhormone 255. Mitteilung [1]. Synthetische Versuche in der Limonin‐Reihe IV Eine neuartige Westphalen‐Lettré‐Umlagerung in der 4,4‐Dimethyl‐Steroid‐Reihe
Authors: Schlatter Hans‐Rudolf , Lüthy Christoph , Graf Walter 
Published: December 2004

AbstractApplying the HgCl2/ClCH2SCH3‐reaction 1. to 4,4‐dimethyl‐Δ5‐7‐oxo‐19‐hydroxy‐androstene (9) one observes an intramolecular rearrangement of the «Westphalen‐Lettré»‐type (→11). A related rearrangement is observed by treating 3‐oxo‐4,4‐dimethyl‐17β‐acetoxy‐Δ5‐androstene (12) with HgCl2/ClCH2SCH3‐reagent (→13). Reaction of 3β, 17β‐diacetoxy‐4,4‐dimethyl‐19‐(methoxymethyl)‐Δ5‐androstene (7) with hydrogenfluoride/urea‐reagent gives rise to a similar rearranged product (→15).
Metal Complexes with Macrocyclic Ligands, VI. The role of substituents on the complexation rate of transition metal ions with several 1,4,7,10‐tetraazacyclotridecanes
Authors: Steinmann Willi , Kaden Thomas A. 
Published: December 2004

Abstract12,12‐Dimethyl‐1,4,7,10‐tetraazacyclotridecane (I), 11,13‐dimethyl‐1,4,7,10‐tetraazacyclotridecane (II), 11,11,13‐trimethyl‐1,4,7,10‐tetraazacyclotridecane (III) and 1,4,7,10,12,12‐hexamethyl‐1,4,7,10‐tetraazacyclotridecane (IV) have been synthesized and their properties are described.While the Ni2+ and Cu2+ complexes of I–III have square planar geometries, those of IV are pentacoordinate according to their absorption spectra. Similarly, while the Co2+ complex of I is octahedral and readily oxygenated, the analogous complex with IV is pentacoordinate and not sensitive to oxygen.The rate of complexation of these ligands with Cu2+ and Ni2+ decreases in the order I > II > III ≫ IV, indicating that the number as well as the position of the methyl groups are important. Finally for Cu2+ the formation of the thermodynamic stable end product is slown down by methyl substitution in α‐position to the coordinating nitrogen atoms (ligand II and III) so that an intermediate can be observed, whereas with I Cu2+ directly forms the end product.
2‐Oxo‐9C(3)‐hydroxy‐ und 2‐Oxo‐9C(7)‐hydroxy‐bicyclo[3.3.1]nonan
Authors: Duthaler Rudolf Otto , Ganter Camille 
Published: December 2004

AbstractA synthesis of the two C(9) epimers 14 and 15 of 2‐oxo‐9‐hydroxy‐bicyclo[3.3.1]nonane is described starting from the two C(2) epimers 3 and 4 of 2‐hydroxy‐9‐oxo‐bicyclo[3.3.1]nonane.
Synthese und reduktive Cyclisierung eines Δ18‐Dehydro‐A/D‐secocorrinkomplexes
Authors: Pfaltz Andreas , Hardegger Bruno , Müller Peter M. , Farooq Saleem , Kräutler Bernhard , Eschenmoser Albert 
Published: December 2004

AbstractA Δ18‐dehydro‐A/D‐secocorrin complex has been synthesized and shown to cyclize smoothly to the corresponding corrin complex by electrochemical reduction in a protonating medium. The crucial step of the construction of the secocorrinoid substrate illustrates a novel variant of the Bamford‐Stevens reaction.
Bis(silyl)chelat‐Komplexe des Eisens
Authors: Fink Walter 
Published: December 2004

AbstractThe reaction of Fe2(CO)9 with 1,2‐bis(dimethylsilyl)benzene, 1,2,4,5‐tetrakis(dimethylsilyl)benzene and vic‐tetrakis(dimethylsilyl)benzene affords bis(silyl)chelate complexes of iron.
Contribution à la phytochimie du genre Gentian, XI Identification de nouveaux dérivés de l'iso‐orientine extraits des feuilles de Gentiana burseri Lapeyr
Authors: Jacot‐Guillarmod André , Duc Luong Minh , Hostettmann Kurt 
Published: December 2004

AbstractTwo new derivates of iso‐orientin have been isolated and identified from the leaves of Gentiana burseri, LAPEYR. The structure of the new compounds were established as: trans‐cafeoyl‐2″‐iso‐orientin (1) and p‐β‐D‐glucosyl‐trans‐cafeoyl‐2″‐iso‐orientin‐4′‐O‐β‐D‐glucoside (2).
Amino‐nucléosides. V. Amino‐3′‐didésoxy‐3′, 5′‐adénosine
Authors: Tronchet Jean M. J. , Graf René , Tronchet Jeannine 
Published: December 2004

AbstractA synthesis of 3′‐amino‐3′, 5′‐dideoxyadenosine is described. This compound is not a substrate of adenosine deaminase.
Dérivés C‐glycosyliques. XXIV. Glycosyl‐4‐thiazoles
Authors: Tronchet Jean M. J. , Eder Hansjörg 
Published: December 2004

Abstract4‐C‐glycosylthiazoles have been prepared by reacting thiourea or thioacetamide with a 6‐S‐benzyl‐6‐chloro‐1,2‐O‐isopropylidene‐3‐O‐methyl‐α‐D‐xylo‐6‐thiohexofuranos‐5‐ulose (7). The latter compound which constitutes an interesting synthetic intermediate in carbohydrate chemistry has been obtained by successive oxidation and chlorination of 6‐S‐benzyl‐1,2‐O‐isopropylidene‐3‐O‐methyl‐α‐D‐6‐thioglucofuranose.
Synthese von 15,16‐Dimethoxy‐8‐oxo‐cis‐erythrinan‐6‐carbonsäureäthylester
Authors: Wilkens Heinrich J. , Troxler Franz 
Published: December 2004

AbstractThe cyclisation of either 1a or 3a with acid yielded the cis‐fused erythrinanone 2; no trans‐isomer could be detected. The structure of this unexpected product was determined by NMR. and confirmed by an X‐ray analysis. Various tetrahydro‐ and hexahydro‐2‐indolinones were prepared to facilitate the interpretation of the NMR.‐spectrum of 2.
Stability, Formation and Dissociation Kinetics of the Pentacoordinate Ni2+ and CO2+ Complexes with 1,5‐Diazacyclooctane‐N,N′‐diacetic Acid
Authors: Chatterjee Chinmay , Kaden Thomas A. 
Published: December 2004

AbstractThe stability constants of the Ni2+ and Co2+ complexes with 1,5‐diazacyclooctane‐N,N′‐diacetic acid (H2DACODA) have been determined potentiometrically in 0.5M KNO3 at 25°. Only M(DACODA) and M(DACODA)OH− were observed.In addition the formation and dissociation kinetics of the pentacoordinate complexes M(DACODA) has been studied in aqueous solution using a stopped‐flow technique. Formation follows the rate law vf = kf [M2+] [HDACODA−]/[H+], which can be interpreted as a bimolecular process either between M2+ and DACODA2− (k) or between MOH+ and HDACODA− (k). The second order rate constants k are much higher than those expected from water exchange and can only be explained by a strong internal conjugate base effect. In the limiting case, however, this is equivalent to the second possible explanation, which assumes MOH+ and HDACODA− as reactive species. The dissociation rate is given by vd = (kML + k [H+]) · [M(DACODA)].
Coleone C, D, I, I′ aus einer madegassischen Plectranthus sp. nov. Interkonversion von cis‐ und trans‐A/B‐6,7‐Diketoditerpenen
Authors: Rüedi Peter , Eugster Conrad Hans 
Published: December 2004

Coleons C, D, I, I′, obtained from a Madagascan Plectranthus sp. nov.. Interconversion of cis‐ and trans‐A/B‐6,7‐Diketoditerpenes.Fairly large amounts of Coleons C and D, as well as Coleons I and I′ (3‐O‐formyl derivative of Coleon I) can bc isolated from the orange glands of an unclassified North Madagascan Plectranthus sp. A reversible transformation of cis‐ and trans‐A/B‐6,7‐dioxo‐abietane via its diosphenol has been achieved for the first time. CD.‐Spectra of these compounds are presented. Hydrogenolysis of Coleon D leads to 6β,16‐dihydroxy‐royleanone.
Gadolinium Break, Tetrad and Double‐double Effects were here, What next??
Authors: Sinha Shyama P. 
Published: December 2004

AbstractIt has been found that the properties of the lanthanide and actinide ions and their complexes vary linearly with the L‐values (the total angular momentum). Usually plots resembling a four segmented «inclined W» are obtained for the whole series, where the data are available. Although some deviation from a symmetrically «inclined W» plot occured in a few cases, the linearity is maintained within the four segments. It is suggested that in future, for correlating the properties of the lanthanide and actinide series, the L‐values rather than the atomic number (Z) or number of the f‐electrons, should be used.
Synthese des Nonactins. (Vorläufige Mitteilung)
Authors: Gerlach Hans , Oertle Konrad , Thalmann Adolf , Servi Stefano 
Published: December 2004

Synthesis of Nonactin.The macrotetrolide antibiotic nonactin (I), containing four units of a C10 hydroxy acid, has been synthesized starting from two adequately protected derivatives (III and IV) of nonactic acid (II). The 32‐membered ring of the macrotetrolide is built up by a sequence of condensation and deprotection steps leading first to a product with two, and subsequently to one with four nonactic acid residues (VIII) which is then cyclized in the presence of Ag+‐ions. Two reactions forming ester bonds have been developed to condense the hydroxy acids and to effect the final cyclization. In one the activation of the carboxyl group is achieved by conversion into the mixed anhydride with 2,4,6‐trimethylbenzene sulfonyl chloride in pyridine. In the other the Ag+‐ion induced reaction of a S‐(2‐pyridyl) hydroxy carbothioate is used to form the corresponding macrocyclic lactone. In the case of nonactin the ring closure is promoted by the coordinating effect of Ag+‐ions present in the reaction mixture.
Chemical Selectivities Disguised by Mass Diffusion I. A simple model of mixing‐disguised reactions in solution. 1st communication on the selectivity of chemical processes
Authors: Ott Roland J. , Rys Paul 
Published: December 2004

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

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

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

AbstractPhotochemistry of 1,1‐dimethyl‐4‐phenyl‐and 1‐Methyl‐1‐phenyl‐1,2‐dihydronaphthalene; evidence for a photochemical, sigmatropic [1,7]H‐shift.Irradiation of 1,1‐dimethyl‐4‐phenyl‐1,2‐dihydronaphthalene (11) and 1‐methyl‐1‐phenyl‐1,2‐dihydronaphthalene (8) in pentane were investigated at −112° to −118°, using a mercury high pressure lamp. The [1,5]‐hydrogen‐shift products 13 and 17, respectively, the [1,7]‐hydrogen‐shift products 15 and 10, respectively and the photochemical Diels‐Alder products 14 and 18, respectively, were obtained, presumably via the ω‐vinyl‐o‐quinodimethane intermediates 12 and 9 (Schema 3).Irradiation of the 1,2‐dihydronaphthalene 11 at −181° to −183° in a 2,2‐dimethylbutane/pentane matrix, gave rise to an UV.‐maximum at 402 nm which is assigned to the o‐quinodimethane derivative 12. After warming the solution around −130° or to room temperature, a product mixture was obtained, which mainly consist of the [1,7]‐hydrogen‐shift product 15 accompanied by the [1,5]‐hydrogen‐shift products 13 and 16 and the photochemical Diels‐Alder product 14 (Table 1). When the o‐quinodimethane intermediate 12 was irradiated with 406 nm‐light, the longwavelength absorption completely disappeared. This solution, after warmingup, yielded mainly the [1,5]‐hydrogen‐shift products 13 and 16 together with the bicyclic compound 14 and surprisingly a small amount of the [1,7]‐hydrogen‐shift product 15 (Table 1).Similar experiments were carried out with the 1,2‐dihydronaphthalene 8. The results clearly indicate that irradiation of the o‐quinodimethane 9 at −180° to −185° with 406 nm‐light caused [1,5]‐ and [1,7]‐hydrogen shifts in a ratio of approximately 1:1 (Table 2).From the experiments described above it follows, that the phenyl‐substituted α‐methyl‐ω‐vinyl‐o‐quinodimethanes 12 and 9 undergo upon irradiation with light of λ > 400 nm, besides photochemical Diels‐Alder reactions, also [1,5]‐ and [1,7]‐ hydrogen shifts.It is remarkable that the thermal [1,7]‐hydrogen‐shifts of the o‐quinodimethanes 12 and 9 occur readily around −130°, whilst a temperature of −70° is needed to promote [1,7]‐hydrogen‐shifts in the non‐phenylated o‐quinodimethanes of the type 2 (Schema 1). The phenyl group in ω‐ or α‐position may enter into conjugation with the π‐system in the helcal transition state of the [1,7]‐hydrogen shift, but not in the reactants 12 and 9.
Carotenoid composition in Safran.
Authors: Pfander Hanspeter , Wittwer Fritz 
Published: December 2004

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

AbstractTwo [4.4.3]propellane lactones 3 and 8 were prepared by employing the chloronitrone reaction. The intermediate propellanes 9 and 12 were also isolated in pure form.