bluuebunny/crossref_metadata_2025 huggingface dataset:
[D‐Ala2, Phe (p‐NO2)4, Leu5]Enkephalin Amide and Nα‐[D‐Ala2, Leu5]‐Enkephalyl‐Nε‐Acetyl‐Lysine Amide: Synthesis and Biological Properties of Prospective Enkephalin Cooperative‐Affinity and Photoaffinity Labels. Preliminary communication
Authors: Castell José V. , Eberle Alex N. , Kriwaczek V. Marly , Tun‐Kyi Aung , Schiller Peter W. , Do Kim Quang , Thanei Peter , Schwyzer Robert
Published: December 2004

As a study preliminary to attempts at photoaffinity and cooperative affinity labelling of cells and cell membrane vesicles bearing opiate receptors, the title compounds were prepared and tested by rat brain membrane binding assays and by a modified guinea‐pig ileum bio‐assay. The potency of the two compounds in both systems was considerably greater than that of the standard peptide, [Leu5]enkephalin, justifying further work with these and similar compounds.
Struktur der Sesquiterpene von Petasites hybridus (L.) G. M.et SCH.: Petasol‐ und Isopetasol‐Abkömmlinge
Authors: Neuenschwander Markus , Neuenschwander Andreas , Steinegger Ernst , Engel Peter
Published: December 2004

Structure of the Sesquiterpenes of Petasites hybridus (L.) G. M. et SCH.: Petasol and Isopetasol Derivatives

The structure of 11 compounds of the sesquiterpene fraction of petasites hybridus has been determined by combination of spectroscopic methods, especially by analysis of the 360‐MHz‐1H‐NMR. spectra. Most natural products are esters of two isomeric sesquiterpene alcohols, characterized by an eremophilan skeleton, namely of petasol as well as of isopetasol. The structure of one key product has been confirmed by X‐ray analysis.
Struktur der Sesquiterpene von Petasites hybridus (L.) G. M. et SCH.: Neopetasol‐Abkömmlinge
Authors: Neuenschwander Markus , Neuenschwander Andreas , Steinegger Ernst
Published: December 2004

Structure of Sesquiterpenes of Petasites hybridus (L.) G. M. et SCH.: Derivatives of Neopetasol

The structure of 5 compounds of the sesquiterpene fraction of petasites hybridus has been determined by combination of spectroscopic methods, especially by analysis of the 360‐MHz‐1H‐NMR. spectra. Most natural products are esters of a sesquiterpene alcohol, which is the 7 β‐epimer of petasol. The alcohol is named neopetasol.
Nouveaux exemples d'acétonides d'aldéhydosucres furanniques
Authors: Tronchet Jean M. J. , Gentile Bernard , Bonenfant Alain P. , Martin Olivier R.
Published: December 2004

Further examples of O‐isopropylidenaldehydosugars in the furanose series

Formyl‐bearing furanose derivatives 1–3 (α‐D‐xylo or α‐D‐erythro configurations) and 5–8 (configurations α‐D‐ribo, α‐D‐lyxo, β‐L‐threo and D‐arabino) have been prepared by classical synthetic steps and their properties mainly spectroscopic, reported. The coupling constant between the formyl and the vicinal proton is always small. Like other members of the series, these new aldehydosugars constitute very useful and flexible synthetic intermediates.
Micellar Solubilization of Proteins in Aprotic Solvents and their Spectroscopic Characterisation
Authors: Luisi Pier Luigi , Bonner Francis J. , Pellegrini Antonio , Wiget Peter , Wolf Romain
Published: December 2004

The quaternary ammonium salt methyl‐trioctylammonium chloride enables the transfer of α‐chymotrypsin, trypsin, pepsin and glucagone from water to cyclohexane. Reversed micelles, whose polar core solubilizes both protein and water, are probably formed in the apolar phase. The influence of various parameters on the phase transfer (concentration, pH, solvent, temperature, etc.) has been investigated.

Absorption, fluorescence and circular dichroism studies of the biopolymers in the cyclohexane system have been carried out. For trypsin and chymotrypsin, the CD. signal in the 200 nm region is very similar in water and in cyclohexane, which suggests that the polypeptide folding is not substantially different in the two phases. The fluorescence quantum yield is always much larger in the cyclohexane phase than in water. The longer wavelength region of the UV. absorption spectrum is slightly red‐shifted relative to water, and a band at 225 nm, probably arising from the aromatic chromophore, is apparent in the organic phase. Reasons for these spectral perturbations are discussed. The enzymes transferred from water into cyclohexane phases can be continuously retransferred into a second water phase. The possible relevance of this ‘double transfer’ as a model for the vectorial transport of biopolymers or a separation technique is discussed.
31P‐NMR. Measurements on Palladium‐Phosphine Complexes. Nuclear overhauser effects and spin‐lattice relaxation times
Authors: Bosch Werner , Pregosin Paul S.
Published: December 2004

The 31P{1H} nuclear Overhauser effects (NOE's) and 31P‐spin‐lattice relaxation times (T1) for a series of trans‐[PdCl2P2], P  PEt3, PPr3n, PBu3n, PMe2Ph, PMePh2, P(p‐Tol)3, P(cyclohexyl)3 complexes are reported. Both the NOE and T1 values depend upon the choice of solvent. The dipole‐dipole mechanism dominates the spin‐lattice relaxation of the coordinated phosphorus atom with the T1 values for the PEt3, PPr3n, and P (cyclohexyl)3 complexes decreasing with increasing molecular weight of the phosphine.
Stereoselektive Synthese von Cyclopropylkohlenhydraten
Authors: Sele Alex , Baehler Bruno , Tronchet Jean M. J.
Published: December 2004

Stereoselective synthesis of cyclopropylsugars

Use of the phase‐transfer catalysis significantly increased the yield of the reactions leading to the known compounds 2 and 3. Stereoselective cyclopropylation of 3 and 4 and 8, was brought about using in the first instance the Simmons‐Smith's reagent, whereas the reaction of dichlorocarbene led to 6 easily dechlorinated to 8. Both diastereoisomeric cyclopropylsugars 4 and 8 were transformed into the corresponding ethyl glycosides.
Lucibufagines. Partie III. Oxo‐11‐et oxo‐12‐bufalines, stéroïdes défensifs des lampyres Photinus ignitus et P. marginellus (Coleoptera: Lampyridae)
Authors: Goetz Michel , Wiemer David F. , Haynes Le Roy W. , Meinwald Jerrold , Eisner Thomas
Published: December 2004

Lucibufagins. Part III

Communication no. 63 de la série ‘Defense Mechanisms of Arthropods’. Pour no. 62, voir [1].

.
11‐Oxo‐and 12‐oxo‐bufalins, defensive steroids from the fireflies Photinus ignitus and P. marginellus (Coleoptera: Lampyridae)

Four lucibufagins (4, 8, 9 and 10), defensive bufadienolides from the fireflies Photinus ignitus and P. marginellus (Coleoptera: Lampyrida), have been isolated and are characterized by spectroscopic means.
Conformations of the 10‐membered Ring in 5, 10‐Secosteroids. II. (E)‐3α‐Acetoxy‐5, 10‐seco‐1 (10)‐cholesten‐5‐one and (E)‐5, 10‐seco‐1 (10)‐cholestene‐3, 5‐dione
Authors: Fuhrer Hermann , Lorenc Ljubinka , Pavlović Vladimir , Rihs Grety , Rist Günther , Kalvoda Jaroslav , Mihailović Mihailo Lj.
Published: December 2004

(E)‐3α‐Acetoxy‐5, 10‐seco‐1(10)‐cholesten‐5‐one (3) was synthesized by fragmentation of 3α‐acetoxy‐5α‐cholestan‐5‐ol (1) using the photochemical version [3] of the lead tetraacetate reaction [4], and transformed into the corresponding 3‐oxo‐compound (5). Two conformations (A and B) were deduced for the 10‐membered ring of 3 by analysis of the 1H‐ and 13C‐NMR. spectra in toluene. The major conformation (A) corresponds to that found in the solid state by X‐ray analysis. According to its NMR. spectra in toluene, the medium‐sized ring of the diketone 5 exists also predominantly in two conformations, the major one being analogous to A (the solid‐state conformation of the 3β‐acetoxy isomer (9) [1]) and the minor one to A (see above). The stereochemistry of the acidcatalyzed and thermal cyclisations of 3 as well as of the corresponding 5‐oxime is discussed in terms of conformational factors.
Inhaltsstoffe des Osmanthus‐Absolues 6. Mitteilung. (7S, 10S, 5E)‐ und (7R, 10S, 5E)‐2,6,10‐Trimethyl‐7,10‐epoxy‐2,5,11‐dodecatrien
Authors: Kaiser Roman , Lamparsky Dietmar
Published: December 2004

Constituents of Osmanthus Absolute, 6th Communication. (7S, 10S, 5E)‐ and (7R, 10S, 5E)‐2,6,10‐Trimethyl‐7,10‐epoxy‐2,5,11‐dodecatriene

Two novel sesquiterpenoid oxides 1a and 1b from Osmanthus absolute have been identified. Their structural proof is based on pectral data and synthesis starting from the known methyl [5‐methyl‐5‐vinyl‐tetrahydrofur‐1‐yl] ketones (4a and 4b, respectively), whose configuration is well established. The thus obtained compounds 1a/1b identical with the natural products, were accompanied by their corresponding 6‐methylidene isomers 3a and 3b which could not be detected in the natural substrate.
Ringerweiterungsreaktionen von N‐(2‐Aminoäthyl)‐, N‐(4‐Aminobutyl)‐, N‐(6‐Amino‐4‐aza‐hexyl)‐ und N‐(8‐Amino‐4‐aza‐octyl)‐lactamen. 7. Mitteilung über Umamidierungsreaktionen
Authors: Stephanou Euripides , Guggisberg Armin , Hesse Manfred
Published: December 2004

Ring Enlargement Reactions of N‐(2‐Aminoethyl)‐, N‐(4‐Aminobutyl)‐, N‐(6‐Amino‐4‐aza‐hexyl)‐ and N‐(8‐Amino‐4‐aza‐octyl)‐lactames

The N‐aminoalkyl‐lactams 1, 3, 4, 10 (Scheme 2) and 13 (Scheme 3) have been synthesized. In the presence of KAPA (potassium 3‐aminopropylamide in 1,3‐propanediamine) 1 is stable, whereas 3, 4 and 10 rearrange under ring enlargement to 5, 8 and 11, respectively. The 4‐aminobutyl derivate 13 rearranges in a fast reaction to 14; after a longer reaction time the 22membered ring 16 and the ring opened product 18 are formed. Hence it may be concluded that the 7membered lactam ring is more stable than the 10membered one, and the 11membered lactam ring is more stable than the 8 membered one. Moreover, the 5‐ and 6 membered ring intermediates of these transamidation reactions are prefered to the 7membered ring intermediates (cf. [10]).
Electrochemical Oxidation of Bis(methylthio)benzenes
Authors: Margaretha Paul
Published: December 2004

The bis(methylthio)benzenes 3a–3c are oxidized to the methylsulfinyl‐methylthiobenzenes 4a–4c on a Pt‐anode in good yields.
Neue Phellandren‐Derivate aus dem Wurzelöl von Angelica archangelicaL
Authors: Escher Sina , Keller Urs , Willhalm Bruno
Published: December 2004

New Phellandrene Derivatives from the Root Oil of Angelica archangelica L.

2‐Nitro‐1,5‐p‐menthadiene (5), trans‐ and cis‐6‐nitro‐1(7), 2‐p‐menthadiene (6 and 7), trans‐1(7), 5‐p‐menthadien‐2‐yl acetate (9) and a formal phellandrene derivative, 7‐isopropyl‐5‐methyl‐5‐bicyclo [2.2.2]octen‐2‐one (16), have been identified in the root oil of Angelica archangelica L. Starting from (−)‐(R)‐α‐phellandrene (1) (R)‐5, (4R, 6S)‐6/(4R, 6R)‐7, (2S, 4R)‐9 and (1R, 4R, 7R)‐16 as well as (2S, 4R)‐11, (2R, 4R)‐12 and (2R, 4R)‐10 have been prepared.
Réaction d'ylures stabilisés sur des aldéhydosucres: influence de divers facteurs dont la structure de l'aldéhydosucre sur le pourcentage d'isomères géométriques obtenu
Authors: Tronchet Jean M. J. , Gentile Bernard
Published: December 2004

Reactions of stabilized ylides with aldehydosugars: influence of some factors, particularly the structure of the aldehydosugar, on the ratio of the geometrical isomers formed

Aldehydosugars bearing no cis‐substituent on the C‐atom β to the carbonyl group (2, 3, 6, 7) or bearing a substituent without an electron lone‐pair (5) gave, upon treatment with acetylmethylidenetriphenylphosphorane, exclusively the E‐isomer, this representing the classical behaviour of aldehydes. On the other hand, aldehydosugars having a lone‐pair bearing substituent (1, 4, 8, 9) gave a mixture of E‐ and Z‐isomers. In the case of most of the aldehydosugars of the latter type (giving some Z‐isomer) a partial epimerization of the C‐atom α to the carbonyl group took place when the solvent of the Wittig reaction was HCONMe2. It is probable that the presence of an electron lone‐pair in the adequate position inhibits the reversion of the kinetic erythro‐betaine, allowing the formation of the Z‐isomer and, in particular solvent conditions, a cycloelimination leading to the epimeric aldehydosugar which ultimately reacts to give the epimeric E‐enone.
Transition Metal Complexes with Bidentate Ligands Spanning trans‐Positions. VIII. The reactions of the nucleophile trans‐[RuCl(NO)(1)] (1 = 2,11‐bis(diphenylphosphinomethyl)benzo[c]‐phenanthrene) with carbon monoxide and the phosphite ligand (2) (2 = 1‐ethyl‐3,5,8‐trioxa‐4‐phosphabicyclo (2.2.2)octane)
Authors: Holderegger Rolf , Venanzi Luigi M. , Bachechi Fiorella , Mura Pasquale , Zambonelli Luigi
Published: December 2004

The preparation of the nucleophile trans‐[RuCl(NO)(1)], where 1 is the bidentate ligand Ph2PCH2C18CH2PPh2, and of the five‐coordinate species [RuCl(CO)(NO)(1)], [RuCl(CO)(NO)(Ph2PCH2Ph)2] and [RuCl(NO)(2)(1)] are reported.

The crystal structure of [RuCl(CO)(NO)(1)] shows that the coordination around the metal atom is distorted trigonal bipyramidal with the phosphorus atoms in axial positions. The RuNO bond angle is 142.8°. 1H‐ and 31P‐NMR. and \documentclass{article}\pagestyle{empty}\begin{document}$ \tilde \nu $\end{document}NO IR.‐data for the above complexes are reported and related to the coordination geometry.
Herstellung der reinen, bicyclischen Olefine Bicyclo[4.2.1]non‐2‐en, Bicyclo[4.2.1]non‐3‐en und Bicyclo[4.2.1]non‐7‐en
Authors: Stamm Erich , Leu Hans‐Rudolf , Keese Reinhart
Published: December 2004

Synthesis of the pure, bicyclic olefines Bicyclo[4.2.1]non‐2‐ene, Bicyclo[4.2.1]non‐3‐ene and Bicyclo[4.2.1]non‐7‐ene

The synthesis of the olefines bicyclo[4.2.1]non‐2‐ene (3), bicyclo[4.2.1]non‐3‐ene (4) and bicyclo[4.2.1]non‐7‐ene (5) of high ‘certified’ purity from one common precursor (7) is described.
The Acid‐catalyzed Hydrolysis of CF3‐deactivated Diazoalkanes
Authors: Dahn Hans , Lenoir John Henri
Published: December 2004

The acid‐catalyzed hydrolysis of CF3CHN2 (1) follows an A2 mechanism of preequilibrium protonation and rate‐determining solvolysis of the intermediate diazonium ion 4; this was demonstrated by: (a) the inverse kinetic isotope effect; (b) H‐D exchange; (c) the unimportance of general acid catalysis; (d) strong rate acceleration by added nucleophiles. The activation parameters have been determined in two solvent systems. In contrast to 1 the secondary diazocompound CF3CN2CH3 (2) follows the normal A‐SE2 mechanism of rate‐determining proton transfer.
Umsetzungen von Dilithio‐nitroalkanen und ‐allylnitroderivaten mit Carbonylverbindungen
Authors: Lehr Friedrich , Gonnermann Jutta , Seebach Dieter
Published: December 2004

Reactions of dilithio‐nitroalkanes and dilithio‐allynitroalkanes with carbonyl compounds

Primary nitro compounds can by acylated via dilithium derivatives 5 with carbonic‐acid derivatives to give α‐nitro esters 6a–i and with carboxylic‐acid esters and anhydrides to give α‐nitroketones 6j–q. In the reaction of 1‐nitro‐1‐buten with two mol‐equiv. of butyllithium, the dilithium compound 10 is formed by successive Michael‐addition and nitronate deprotonation. Dilithium derivatives 5 also react with ketones and benzaldehyde (→18a–g); the nitro aldols 25 and 26 are likewise formed by addition of doubly deprotonated allylic nitro compounds. Some of the products have been further transformed by reduction or by Nef‐reactions to the hydrochloride of the α‐amino‐acid 26, to 2‐amino‐alcohols 28a and 28b, to α‐hydroxyamino‐acid esters 27a–c, to α‐hydroxyimino esters 35 and 36, to α‐hydroxyimino ketones 31 and 33, to the α‐diketone 34, and to the α‐keto ester 37.
Favorskii‐Umlagerung in Gegenwart von 3,4‐Dimethoxyfuran: 11endo‐oxa‐tricyclo [4.3.1.12,5]undec‐3‐en‐10‐on und Derivate
Authors: Matzinger Peter , Eugster Conrad Hans
Published: December 2004

Favorskii‐rearrangement in the presence of 3,4‐dimethoxyfuran: preparation of 3,4‐dimethoxy 11endo‐oxo‐tricyclo [4.3.1.12,5]undec‐3‐en‐10‐one and any derivatives

On treatment with sodiumhydride of 2‐chloro‐cyclohexanone in the presence of 3,4‐dimethoxyfuran, a possible intermediate of the Favorskii‐rearrangement has been trapped as 3,4‐dimethoxy‐11endo‐oxa‐tricyclo [4.3.1.12,5]undec‐3‐en‐10‐one (3). This new compound contains a highly nucleophilic double bond. It can be cleaved in high yield by ozonolysis to 2exo, 4exo‐bis (methoxycarbonyl)‐3‐oxabicyclo [3.3.1]nonan‐9‐one (4). Addition of chlorine to 3 occurs in stereoselective exo‐cis‐manner to the crystalline 3exo, 4exo‐dichloro‐3endo,4endo‐dimethoxy 11endo‐oxa‐tricyclo [4.3.1.12,5]undecan‐10‐one (5). Silver ion assisted hydrolysis of 5, followed by thermal treatment of the intermediate hydrates, leads to the red 11endo‐oxa‐tricyclo [4.3.1.12,5]undecan‐3,4, 10‐trione (6), and methanolysis to 3,3,4,4‐tetramethoxy‐11endo‐oxa‐tricyclo [4.3.1.12,5]undecan‐10‐one (8). By photolytic decarbonylation, 8 is converted into 3,3,4,4‐tetramethoxy‐10‐oxa‐tricyclo‐[4.3.12,5.0]decan (9).
The Effects of Homoconjugated Cyclopropane and Oxirane Rings on the Diels‐Alder Reactivity of 2,3‐bis (methylidene)norbornane
Authors: Pilet Olivier , Chollet André , Vogel Pierre
Published: December 2004

Preparation of 6exo, 7exo‐bis (methylidene)‐tricyclo[3.2.1.02,4]octane (6) is described. The reactivity of 6 towards tetracyanoethylene is evaluated and compared with that of exo‐2,3‐epoxy‐5,6‐bis (methylidene)norbornane (5), 2,3‐bis‐(methylidene)norbornane (1) and other related dienes. The cyclopropane group in 6 exerts an unsignificant rate retardation effect on the Diels‐Alder reactivity of this diene relative to that of 1, whereas a relatively important rate retardation effect is caused by the exo‐oxirane ring in 5. The observed effects are probably due to electronic factors (through‐space and through‐bond interactions).
Cob(I)alamin als Katalysator, 5. Mitteilung [1]. Enantioselektive Reduktion α,β‐ungesättigter Carbonylderivate
Authors: Fischli Albert , Süss Daniel
Published: December 2004

Cob(I)alamin as Catalyst. 5. Communication [1]. Enantioselective Reduction of α,β‐Unsaturated Carbonyl Derivatives

The cob(I)alamin‐catalyzed reduction of an α,β‐unsaturated ethyl ester in aqueous acetic acid produced the (S)‐configurated saturated derivative 2 with an enantiomeric excess of 21%. The starting material 1 is not reduced at pH = 7.0 in the presence of catalytic amounts of cob(I)alamin (see Scheme 2). It is shown that the attack of cob(I)alamin and not of cob(II)alamin, also present in Zn/CH3COOH/H2O, accounts for the enantioselective reduction observed. All the (Z)‐configurated starting materials 1, 3, 5, 7, 9 and 11 have been transformed to the corresponding (S)‐configurated saturated derivatives 2, 4, 6, 8, 10 and 12, respectively. The highest enantiomeric excess revealed to be present in the saturated product 12 (32,7%, S) derived from the (Z)‐configurated methyl ketone 11 (see Scheme 3 and Table 1). The reduction of the (E)‐configurated starting materials led mainly to racemic products. A saturated product having the (R)‐configuration with a rather weak enantiomeric excess (5.9%) has been obtained starting from the (E)‐configurated methyl ketone 23 (see Scheme 5 and Table 2). The allylic alcohols 16 and 24 have been reduced to the saturated racemic derivative 17.
Alkali Cation Complexation and Transport Properties of Synthetic Bicyclic Decapeptides: Structural, Thermodynamic, and Kinetic Analysis
Authors: Moeschler Hans J. , Sargent David F. , Tun‐Kyi Aung , Schwyzer Robert
Published: December 2004

Alkali cation complexation and bilayer transport by the bicyclic decapeptides S,S′‐bis‐cyclo‐glycyl‐L‐hemicystyl‐glycyl‐glycyl‐L‐prolyl (1), S, S′‐bis‐cyclo‐glycyl‐L‐hemicystyl‐glycyl‐glycyl‐D‐prolyl (2), S, S′‐bis‐cyclo‐glycyl‐L‐ hemicystyl‐sarcosyl‐sarcosyl‐L‐prolyl (3), and S, S′‐bis‐cyclo‐glycyl‐L‐hemicystyl‐sarcosyl‐sarcosyl‐D‐prolyl (4) were analyzed according to structural, thermodynamic and kinetic criteria; valinomycin was used as a reference ionophoretic system.

Structural analysis of peptide 3 with spectroscopic methods showed different conformational arrangements in the bicyclic system depending on its state of complexation. Circular dichroism indicated the presence of a multitude of conformations with differing helicities around the disulfide bridge in both free and complexed states.

Thermodynamic analysis by microcalorimetry demonstrated a far lower cation selectivity among the synthetic peptides than displayed by valinomycin. Peptide 3 shows cation affinities of about two orders of magnitude higher than peptide 4, but still much lower than found for the complexes of valinomycin with K+ and Rb+. In contrast to the latter case, the complexation reactions of peptides 3 and 4 are driven by both enthalpy and entropy contributions. Neither peptide 1 and 2 nor the cyclic partial structures of all four peptides displayed significant cation complexation.

A kinetic analysis of the K+‐complexation by peptide 3 based on the microcalorimetry experiments showed far lower rates of cation exchange for the synthetic peptide than those reported for valinomycin. Transport studies with peptide 3 using artificial lipid bilayer membranes gave negative results. The apparent lack of ionophoretic properties of these synthetic peptides despite their considerable ability to form complexes with cations is discussed in terms of structural parameters.
Herstellung einiger verzweigter Paraffine im oligomeren Bereich
Authors: Zeltner Peter , Huber Gustav A. , Peters Reinhard , Tátrai Ferenc , Boksányi László , sz. Kováts Ervin
Published: December 2004

Synthesis of some branched paraffins of high molecular weight

Synthesis and properties of two series of branched paraffins of high molecular weight are described. In the course of the preparation of one of the starting materials the Wolff‐Kishner reduction of a sterically hindered ketone, unstable in basic medium, has been elaborated.
The Removal of S‐Cysteine Protection by Means of 2‐Pyridine Sulfenyl Chloride and the Subsequent Formation of Disulfide Bonds. Preliminary communication
Authors: Castell José V. , Tun‐Kyi Aung
Published: December 2004

2‐Pyridine sulfenyl chloride (PS‐Cl) is a useful reagent for simultaneously deprotecting and activating the mercapto‐group of cysteine and of cysteine‐peptides preliminary to disufide‐bond formation. The S‐protecting groups that are amenable to this reaction include trityl, diphenylmethyl, acetamidomethyl, t‐butyl, and t‐butylsulfenyl.
The Structure of the Antibiotic Hedamycin. V. Crystal structure and absolute configuration
Authors: Zehnder Margareta , Séquin Urs , Nadig Heinz
Published: December 2004

The crystal structure of the antibiotic hedamycin (1) has been solved by direct method and refined by least squares techniques to R = 0.091 for 2289 of 2643 independent reflexions. Crystals of C41H50N2O11 are orthorhombic, space group P212121 with lattice parameters a = 24.239 (12), b = 21.440 (10), c = 7.369 (4) Å, Z = 4. The structural features of hedamycin derived earlier by chemical and spectroscopical means are confirmed. Optical rotation and circular dichroism indicate that hedamycin (1) has the absolute configuration of the related antibiotic kidamycin (3). The conformation of ring F is a chair form with the aryl substituent almost axial. The bioxirane part of the antibiotic is in a synclinal conformation.
The Absolute Configuration of the Fungal Metabolite Verrucarin B. Biosynthetic Consequences. Verrucarins and roridins, 36th communication
Authors: Breitenstein Werner , Tamm Christoph , Arnold Edward V. , Clardy Jon
Published: December 2004

The absolute configuration of verrucarin B (2) has been determined by a single crystal X‐ray diffraction analysis. This result permits the stereochemistry of the biogenetic transformation of mevalonic acid (12) to verrucarinic acid (7) to be deduced.
Diterpenoide Drüsenfarbstoffe aus Labiaten: 11 Coleone und Royleanone aus Coleus carnosus HASSK
Authors: Yoshizaki Fumihiko , Rüedi Peter , Eugster Conrad Hans
Published: December 2004

Diterpenoid Leaf‐Gland Pigments: 11 Coleons and Royleanones from Coleus carnosus HASSK.

The above mentioned plant has been investigated for its leaf‐gland pigments. The following diterpenoids have been isolated (listed according to their elution from Sephadex LH‐20, SiO2 and polyamide; in parentheses the yield of each product in g/kg dried leafs): royleanone (1)/6,7‐dehydroroyleanone (2) (0.004, as a mixture); 7α‐acetyloxyroyleanone (3, 0.009); a novel dimeric diterpene of hitherto unknown structure (0.03); horminone (4, 0.08); 6β‐hydroxyroyleanone (5, 0.04, new as a natural product); 7α‐acetyloxy‐6β‐hydroxyroyleanone (6, 5.45); 6β, 7α‐dihydroxyroyleanone (7, 1.20); 7α‐acetyloxy‐6β, 20‐dihydroxyroyleanone (8, 0.046, a novel compound); coleon U (9, 1.32); coleon V (10, 13.84); carnosolone (6α, 11, 12‐trihydroxy‐6,20‐epoxymethano‐abieta‐8, 11, 13‐trien‐7‐one (11), 1.25, a novel compound).

Therefore, this plant is one of the richest one in royleanones and coleons so far investigated by us (pure crystalline compounds 2,3%, estimated total amount > 3% of dry weight). Among the isolated compounds carnosolone (11) is of special interest being the first of a group of colourless diterpenoids from Coleus‐ and Plectranthus‐ species turning blue on TLC. Its oxydation product 12 is one of the rare 4‐acyl‐ortho‐quinones having high reactivity and characteristic spectral properties.
Eine Suche nach 3′‐Epilutein ( = (3R,3′S,6′R)‐β,ε‐Carotin‐3,3′‐diol) und 3′, O‐Didehydrolutein (=(3R, 6′R)‐3‐Hydroxy‐β,ε‐carotin‐3′‐on) in Eigelb, in Blüten von Caltha palustris und in Herbstblättern
Authors: Buchecker Richard , Eugster Conrad Hans
Published: December 2004

Search for the Presence in Egg Yolk, in Flowers of Caltha palustris and in Autumn Leaves of 3′‐Epilutein ( =(3R,3′S,6′R)‐β,ε‐Carotene‐3,3′‐diol) and 3′,O‐Didehydrolutein ( =(3R,6′R)‐3‐Hydroxy‐β,ε‐carotene‐3′‐one)

3′.O‐Didehydrolutein ( =(3R, 6′R)‐3‐hydroxy‐β,ε‐carotene‐3′‐one; 2) has been detected in egg yolk and in flowers of Caltha palustris. This is the first record for its occurrence in a plant. The compound shows a remarkable lability towards base; therefore, it may have been overlooked til now, because it is destroyed under the usual conditions of saponification of the carotenoid‐esters. One of the many products formed from 2 with 1% KOH in methanol has been purified and identified as the diketone 3 ( =(3R)‐3‐hydroxy‐4′, 12′‐retro‐β,β‐carotene‐3′,12′‐dione). The identification of this transformation product from lutein might throw a new light on the metabolism of this important carotenoid in green plants.

3′‐Epilutein ( =(3R,3′S,6′R)‐β,ε‐carotene‐3,3′‐diol; 1) was not detected in egg yolk, but is present besides lutein in flowers of C. palustris, thus confirming an earlier report of the occurrence of an isomeric (possibly epimeric) lutein (‘calthaxanthin’) in that plant [21].

We were not able to detect even traces of 1 or 2 in the carotenoid fraction from autumn leaves of Prunus avium (cherry), Parrotia persica, Acer montanum (maple) and yellow needles of Larix europaea (larch).

α‐Cryptoxanthin (4), a very rare carotenoid, was isolated in considerable quantity for the first time from flowers of C. palustris.
Substituent and Isotope Effects on the Hydrolysis Rates of 2‐Aryl‐2‐diazocarboxylic Esters
Authors: Bui‐Nguyen Mai‐Huong , Dahn Hans , McGarrity John F.
Published: December 2004

The overall kinetic solvent isotope effects on the acid catalyzed hydrolysis of a series of 2‐aryl‐2‐diazocarboxylic esters ArCN2COOCH3, and one 2‐aryl‐2‐diazocarboxamide C6H5CH2CON (CH3)2 vary inversely with the reactivity of the substrate, between limits of 3.14 and 1.46. A linear Hammett plot for the hydrolysis rates of the a‐diazocarboxylic esters indicates that there is no mechanistic change for the hydronium‐ion‐catalyzed reaction. The relation between hydrolysis rate and buffer acid concentration deviates from linearity for high values of the latter. It is shown on the basis of the solvent isotope effects for the non‐linear region that this deviation does not stem from a mechanistic change caused by the buffer base component. The specific salt effects on the general acid‐catalyzed reaction are discussed.
Photofragmentation of Dibenzyl Ketone in the Presence of Tetramethylpiperidine Derivatives. Studies on light stabilizer mechanisms [1]
Authors: Felder Bruno , Schumacher Rolf , Sitek Franciszek
Published: December 2004

The interaction of selected tetramethylpiperidine derivatives with radicals arising from the Norrish‐type I cleavage of dibenzyl ketone under oxygen was studied. Product analyses and kinetic studies showed that the investigated sterically hindered piperidine derivatives have a pronounced effect on both the nature and distribution of the products of photolysis of dibenzyl ketone in the presence of oxygen. Observations indicated that the phenylperacetoxyl radical is formed as an intermediate during irradiation and that it interacts with the additives used. Possible mechanisms of the reactions studied are discussed.

The observation that oxidation of an isolated double bond by the radicals formed in dibenzyl ketone photolysis under oxygen is strongly inhibited in the presence of the studied sterically hindered amines is discussed in the light of the results presented. The findings are considered in relation to the problem of polymer stabilization.
Herstellung vonerythro‐2‐Hydroxybernsteinsäure‐Derivaten aus Äpfelsäureester. Vorläufige Mitteilung
Authors: Seebach Dieter , Wasmuth Daniel
Published: December 2004

Preparation forerythro‐2‐Hydroxy‐succinic Acid Derivatives from Malic Esters

As a contribution to the much discussed diastereoselective synthesis of enantiomers of open chain compounds, > 90%erythro‐selective branching of malic esters by alkylation of the doubly deprotonated derivative2(alkoxide‐enolate) with methyl, allyl, and benzyl halides in THF at −78° (→3aa, 3ba, 3bb, 3bc,Table 1) is described. A second alkylation (→4) and addition of2to acetone (→5) are also possible. Cyclization of2to the enantiomerically puretrans‐epoxides6is achieved by treatment with iodine. Cuprate opening of6bfurnishes the same product3baobtained from the methylation of2b, establishing the configurational assignment.
Contribution à la phytochimie du genre Gentiana. XXV. Etude des composés flavoniques et xanthoniques dans les feuilles de Gentiana X marcailhouana RY. Nouveaux cinnamoyl‐C‐glucosides flavoniques
Authors: Luong Par Minh Duc , Fombasso Pierre , Jacot‐Guillarmod André
Published: December 2004

Phytochemistry of genus Gentiana XXV: Study of the flavonic and xanthonic compounds in leaves of Gentiana X marcailhouana RY. New cinnamoyl‐C‐glucosyl‐flavones

Nine flavonic compounds: isoorientin (1), isovitexin (2), isoorientin‐4′‐O‐β‐D‐glucoside (3), isovitexin‐4′‐O‐β‐D‐glucoside (4), luteolin‐7‐O‐β‐D‐glucoside (5), trans‐cafeoyl‐2′′‐isoorientin (6), trans‐feruloyl‐2′′‐isoorientin (7), trans‐p‐coumaroyl‐2′′‐isoorientin (8), p‐O‐β‐D‐glucosyl‐trans‐cafeoyl‐2′′‐isoorientin (9) and three xanthones: gentioside (10), isogentisine (11), mangiferin (12), have been identified from leaves of Gentiana X marcailhouana RY. Compounds 8 and 9 were described for the first time. The cyclitol L‐(+)‐bornesitol (13) has been also isolated.
Synthesis of Spirocyclic Tetrahydrofuran Derivatives of Monocyclonerolidol
Authors: Schulte‐Elte Karl H. , Umiker Thomas , Ohloff Günther
Published: December 2004

Eighteen new sesquiterpenoid theaspirane derivatives 3–20, representing potential natural compounds, were synthesized from 1,2‐didehydro‐β‐monocyclonerolidol (1). Their structure and configuration were determined by spectroscopic methods.
Ein einfacher Zugang zu 3‐Amino‐nocardicinsäure. Modifikationen von Antibiotika. 17. Mitteilung [1]
Authors: Schaffner‐Sabba Karl , Müller Beat W. , Scartazzini Riccardo , Wehrli Hansuli
Published: December 2004

A Simple Route to 3‐Amino‐nocardicinic Acid

Starting from nocardicin A (1), a novel and efficient procedure for the preparation of 3‐amino‐nocardicinic acid (4) and its protected derivatives 6 and 8–11 is described.
Strukturelle Abwandlungen an partiell silylierten Kohlenhydraten mittels Triphenylphosphin/Azodicarbonsäure‐diäthylester. 3. Mitteilung [1]
Authors: Brandstetter Hannelore H. , Zbiral Erich
Published: December 2004

Structural Modification on Partially Silylated Carbohydrates by Means of Triphenylphosphine/Diethyl Azodicarboxylate

Reaction of methyl 2, 6‐bis‐O‐(t‐butyldimethylsilyl)‐β‐D‐glucopyranoside (1a) with triphenylphosphine (TPP)/diethyl azodicarboxylate (DEAD) and Ph3P · HBr or methyl iodide yields methyl 3‐bromo‐2, 6‐bis‐O‐(t‐butyldimethylsilyl)‐3‐deoxy‐β‐D‐allopyranoside (3a) and the corresponding 3‐deoxy‐3‐iodo‐alloside 3c (Scheme 1). By a similar way methyl 2, 6‐bis‐O‐(t‐butyldimethylsilyl)‐α‐D‐glucopyranoside (2a) can be converted to the 4‐bromo‐4‐deoxy‐galactoside 4a and the 4‐deoxy‐4‐iodo‐galactoside 4b. In the absence of an external nucleophile the sugar derivatives 1a and 2a react with TPP/DEAD to form the 3,4‐anhydro‐α‐ or ‐β‐D‐galactosides 5 and 6a, respectively, while methyl 4, 6‐bis‐O‐(t‐butyldimethylsilyl)‐β‐D‐glucopyranoside (1b) yields methyl 2,3‐anhydro‐4, 6‐bis‐O‐(t‐butyldimethylsilyl)‐β‐D‐allopyranoside (7a, s. Scheme 2). Even the monosilylated sugar methyl 6‐O‐(t‐butyldimethylsilyl)‐α‐D‐glucopyranoside (2b) can be transformed to methyl 2,3‐anhydro‐6‐O‐(t‐butyldimethylsilyl)‐β‐D‐allopyranoside (8; 56%) and 3,4‐anhydro‐α‐D‐alloside 9 (23%, s. Scheme 3). Reaction of 1c with TPP/DEAD/HN3 leads to methyl 3‐azido‐6‐O‐(t‐butyldimethylsilyl)‐3‐deoxy‐β‐D‐allopyranoside (10). The epoxides 7 and 8 were converted with NaN3/NH4Cl to the 2‐azido‐2‐deoxy‐altrosides 11 and 13, respectively, and the 3‐azido‐3‐deoxy‐glucosides 12 and 14, respectively (Scheme 4 and 5). Reaction of 7 and 8 with TPP/DEAD/HN3 or p‐nitrobenzoic acid afforded methyl 2,3‐anhydro‐4‐azido‐6‐O‐(t‐butyldimethylsilyl)‐4‐deoxy‐α‐ and ‐β‐D‐gulopyranoside (15 and 17), respectively, or methyl 2,3‐anhydro‐6‐O‐(t‐butyldimethylsilyl)‐4‐O‐(p‐nitrobenzoyl)‐α‐ and ‐β‐D‐gulopyranoside (16 and 18), respectively, without any opening of the oxirane ring (s. Scheme 6). ‐ The 2‐acetamido‐2‐deoxy‐glucosides 19a and 20a react with TPP/DEAD alone to form the corresponding methyl 2‐acetamido‐3,4‐anhydro‐6‐O‐(t‐butyldimethylsilyl)‐2‐deoxy‐galactopyranosides (21 and 22) in a yield of 80 and 85%, respectively (Scheme 7). With TPP/DEAD/HN3 20a is transformed to methyl 2‐acetamido‐3‐azido‐6‐O‐(t‐butyldimethylsilyl)‐2,3‐didesoxy‐β‐D‐allopyranoside (25, Scheme 8). By this way methyl 2‐acetamido‐3,6‐bis‐O‐(t‐butyldimethylsilyl)‐α‐D‐glucopyranoside (19b) yields methyl 2‐acetamido‐4‐azido‐3,6‐bis‐O‐(t‐butyldimethylsilyl)‐2,4‐dideoxy‐α‐D‐galactopyranoside (23; 16%) and the isomerized product methyl 2‐acetamido‐4,6‐bis‐O‐(t‐butyldimethylsilyl)‐2‐deoxy‐α‐D‐glucopyranoside (19d; 45%). Under the same conditions the disilylated methyl 2‐acetamido‐2‐deoxy‐glucoside 20b leads to methyl 2‐acetamido‐4‐azido‐3,6‐bis‐O‐(t‐butyldimethylsilyl)‐2,4‐dideoxy‐β‐D‐galactopyranoside (24). ‐ All Structures were assigned by 1H‐NMR. analysis of the corresponding acetates.
IsoméRisation avant la perte d'eau des ions aldéhydes et cétones protonés en spectrométrie de masse
Authors: Audier Par Henri Edouard , Milliet Arielle , Tabet Jean‐Claude
Published: December 2004

Isomerization of Protonated Aldehyde and Ketone Ions in the Mass‐Spectrography Before the Loss of Water

In mass spectrometry, protonated aldehyde and ketone ions isomerize before the loss of a molecule of water. In order to specify this process, the spectra of deuterium labelled protonated aldehydes and ketones have been compared to the spectra of the corresponding isomer ions.
Total Synthesis of Indole and Dihydroindole Alkaloids. XVIII. Isomers and analogues of vinblastine
Authors: Kutney James P. , Honda Toshio , Kazmaier Peter M. , Lewis Norman J. , Worth Brian R.
Published: December 2004

The synthesis and conformational analysis of (3′R)‐3‐hydroxyleurosidine (5), (3′S)‐3‐hydroxyleurosidine (10), (3′S)‐3‐acetoxy‐4′‐deoxyleurosidine (15), (3′R)‐3‐acetoxy‐4′‐deoxyleurosidine (23), (3′R)‐3‐acetoxy‐4′‐deoxyvinblastine (16), (3′S)‐3‐acetoxy‐4′‐deoxyleurosidine (28) is discussed.
Zur Synthese sulfonierter Derivate von 2,3‐Dimethylanilin und 3,4‐Dimethylanilin
Authors: Courtin Alfred , Tobel Hans‐Rudolf Von
Published: December 2004

On the Synthesis of Sulfonated Derivatives of 2,3‐Dimethylaniline and 3,4‐Dimethylaniline

Baking the hydrogensulfate salt of 2,3‐dimethylaniline (1) or of 3,4‐dimethylaniline (2) led to 4‐amino‐2,3‐dimethylbenzenesulfonic acid (4) and 2‐amino‐4,5‐dimethylbenzenesulfonic acid (5), respectively (Scheme 1). The sulfonic acid 5 was also obtained by treatment of 2 with sulfuric acid or by reaction of 2 with amidosulfuric acid. 3‐Amino‐4,5‐dimethylbenzenesulfonic acid (3) and 5‐Amino‐2,3‐dimethylbenzenesulfonic acid (6) were prepared by sulfonation of 1,2‐dimethyl‐3‐nitrobenzene (9) to 3,4‐dimethyl‐5‐nitrobenzenesulfonic acid (11) and of 1,2‐dimethyl‐4‐nitrobenzene (10) to 2,3‐dimethyl‐5‐nitrobenzenesulfonic acid (12), respectively, with subsequent Béchamp reduction (Scheme 1). Preparations of 2‐amino‐3,4‐dimethylbenzenesulfonic acid (7) and of 6‐amino‐2,3‐dimethylbenzenesulfonic acid (8) were achieved by the sulfur dioxide treatment of the diazonium chlorides derived from 3,4‐dimethyl‐2‐nitroaniline (24) and from 2,3‐dimethyl‐6‐nitroaniline (31) to 3,4‐dimethyl‐2‐nitrobenzenesulfonyl chloride (29) and 2,3‐dimethyl‐6‐nitrobenzenesulfonyl chloride (32), respectively, followed by hydrolysis to 3,4‐dimethyl‐2‐nitrobenzenesulfonic acid (30) and 2,3‐dimethyl‐6‐nitrobenzenesulfonic acid (33), and final reduction (Scheme 3). Compound 7 was also synthesized by reaction of 4‐chloro‐2,3‐dimethylaniline (23) with amidosulfuric acid to 2‐amino‐5‐chloro‐3,4‐dimethylbenzenesulfonic acid (20) and subsequent hydrogenolysis (Scheme 2). 4′‐Bromo‐2′, 3′‐dimethyl‐acetanilide (13) and 4′‐chloro‐2′, 3′‐dimethyl‐acetanilide (14) on treatment with oleum yielded 5‐acetylamino‐2‐bromo‐3,4‐dimethylbenzenesulfonic acid (17) and 5‐acetylamino‐2‐chloro‐3,4‐dimethylbenzenesulfonic acid (18), respectively. Their structures were proven by hydrolysis to 5‐amino‐2‐bromo‐3,4‐dimethylbenzenesulfonic acid (21) and 5‐amino‐2‐chloro‐3,4‐dimethylbenzenesulfonic acid (22), followed by reductive dehalogenation to 3.
Über Pterinchemie. 73. Mitteilung [1]. Zum Verlauf der katalytischen Reduktion von 7‐Methylpterin
Authors: Ganguly Abhoy N. , Sengupta Pradip K. , Bieri Jost H. , Viscontini Max
Published: December 2004

On the Pathway of the Catalytic Reduction of 7‐Methylpterin

The catalytic hydrogenation of 7‐methylpterin (VII) in a neutral solution occurs first by the reduction of the 7,8‐double bond (thermodynamically‐controlled reaction) followed by the reduction of the 5,6‐double bond. On the contrary, in an acidic medium like CF3COOH, the 5,6‐double bond is reduced first (kinetically‐controlled reaction). The dihydro‐intermediate then undergoes a [1,2]‐H‐rearrangement leading to the formation of the thermodynamically more stable 7‐methyl‐7,8‐dihydropterin (XV) which on further reduction gives 7‐methyl‐5,6,7,8‐tetrahydropterin (VIII). The catalytic reduction of 7‐methyl‐7,8‐dihydropterin (XV) with deuterium gives stereoselectively a sole product with D at C(6) in the equatorial position.
Synthèse de N‐Alkyl‐arylamines par Thermolyse ou Photolyse d'Alkyl‐3‐diaryl‐1,3‐triazènes
Authors: Julliard Par Michel , Vernin Gaston , Metzger Jacques
Published: December 2004

Synthesis of N‐Alkyl‐arylamines by Thermolysis or Photolysis of 3‐Alkyl‐1,3‐bis(p‐chlorophenyl)triazenes

The thermolysis of 3‐alkyl‐1,3‐bis(p‐chlorophenyl)triazenes in benzene or methanol leads to the formation of N‐alkyl‐p‐chloroanilines (2) in 19–50% yield, N‐alkyl‐bis(p‐chlorophenyl)amines (3) in 7.5–15.5% yield and 4,4′‐dichlorobiphenyle (4) in 1–7% yield; besides with benzene as the substrate, 4‐chlorobiphenyle (5) (12–20% yield) was also formed. The photolysis in methanol gives only the N‐alkyl‐p‐chloroanilines (2) in 32–40% yield. In these two cases the results are consistent with a radical pair formation in a solvent cage, recombination (thermolysis) and/or diffusion (thermolysis and photolysis) with intermolecular abstraction of hydrogen. A free radical chain mechanism is involved in the photolytic process and the quantum yield is high.
Photochemical Rearrangement of a Steroidal α,β‐Epoxylactone. Photochemical reactions, XI [1]
Authors: Caus María Jesús , Cánovas Antonio , Bonet Juan‐Julio
Published: December 2004

The UV. irradiation of 17β‐acetoxy‐4α, 5α‐epoxy‐2‐oxaandrostan‐3‐one (7) yields 17β‐acetoxy‐2‐oxa‐10(5 → 4)abeo‐4ζ (H)‐androsta‐3,5‐dione (11). A non‐photochemical synthesis of 11, proceeding in lower yield, is also described.
Specific Ligands for the Affinity Chromatography of Cholinergic Proteins
Authors: Riggio Gaetano , Hopff Wolfgang Herbert , Hofmann Alfred André , Waser Peter Gaudenz
Published: December 2004

Affinity chromatography of proteins requires a ligand covalently bound to a solid support separated by a spacer of sufficient length. In the specific case of acetyl‐cholinesterase we have reduced the conventional spacer synthesis from five to three steps.

For affinity chromatography of cholinergic proteins the ideal ligand would be acetylcholine which, however, could not be used because it is easily hydrolyzed. We synthesized hydrolysis‐resistent ligands. Different specific ligands were synthesized for the affinity chromatography of serum esterase.
Aromatic Radical Anions in Neat Aromatic Hydrocarbons as Solvents. Direct evidence of through space spin‐density transfer to the ligand of the counter ion
Authors: Belser Peter , Desbiolles Guy , Ochsenbein Ueli , von Zelewsky Alexander
Published: December 2004

Contact ion pairs of aromatic radical anions, with a crown ether complex of potassium as cation in a neat aromatic hydrocarbon, can be obtained by reducing the aromatic hydrocarbon in which a small amount of crown ether is dissolved. The unpaired electron stays attached to one aromatic molecule during a time interval which is long on the ESR. time scale. The radicals are stabilized by ion‐pair formation in the low polarity solvent. As a consequence of this stabilization, radicals of compounds with low electron affinities, e.g. mesitylene, can be prepared. Mesitylene, m‐xylene, and toluene show additional hyperfine splitting in the ESR. spectra of their anion radical pairs of the order of 18 μT. The proton ENDOR. spectra have signals at the corresponding frequencies, indicating a hyperfine coupling with protons of the crown ether ligand. Using mixtures of two aromatic compounds, their relative electron affinities can be determined by studying the temperature dependence of the radical concentrations.
Notiz zur Synthese von (E)‐12‐Hydroxy‐10‐heptadecensäure, (5E, 10E)‐12‐Hydroxy‐5, 10‐heptadecadiensäure und (5Z, 10E)‐12‐Hydroxy‐5,10‐heptadecadiensäure
Authors: Kienzle Frank
Published: December 2004

Note on the Synthesis of (E)‐12‐Hydroxy‐10‐heptadecenoic Acid, (5E, 10E)‐12‐Hydroxy‐5, 10‐heptadienoic Acid and (5Z, 10E)‐12‐Hydroxy‐5,10‐heptadienoic Acid

The syntheses of two heptadecadienoic and one heptadecenoic acid, compounds which formally may be derived from prostaglandin‐like molecules by removal of a C3‐fragment from the five‐membered ring, are described.
Photochemische reaktionen. 108. Mitteilung. Photochemistry of N‐acylazoles. VI. Photoreactivities of 1‐acyl‐1,2,4‐triazoles and of 2‐acyltetrazoles
Authors: Murato Kazuo , Yatsunami Takashi , Iwasaki Shigeo
Published: December 2004

Contrary to the findings in the photolysis of N‐acylimidazoles [2] irradiation of 1‐acyl‐1,2,4‐triazoles afforded no photo‐Fries product, but instead products formed via the corresponding acyl radicals and aldehydes. Photolysis of 2‐acyltetrazoles gave in part the same products as those obtained from the irradiation of the corresponding acyl‐triazoles as well as 2‐alkyl‐1,3,4‐oxadiazoles. N‐Acyltetrazoles didn't give any photo‐Fries product neither.
Synthesen und pharmakologische Eigenschaften von 2,2‐Dialkyl‐5‐aryl‐3‐pyridylpyrrolidinen
Authors: Aeppli Lislott , Bernauer Karl , Schneider Fernand , Strub Konrad , Oberhänsli Willi E. , Pfoertner Karl‐Heinz
Published: December 2004

Syntheses and Pharmacological Properties of 2,2‐Dialkyl‐5‐aryl‐3‐pyridylpyrrolidines

Reaction of the photochemically generated benzonitrile methylides 2 with vinylpyridines yields 2‐aryl‐4‐pyridyl‐1‐pyrrolines 3. Depending on reduction methods, the compounds 3 are selectively transformed to the corresponding cis‐ or the trans‐substituted pyrrolidines 10 or 11, respectively. Furthermore, a non‐photochemical synthesis has been developed: the easily available nitro‐ketones 8 provide through reductive cyclization the pyrrolines 3 or directly the pyrrolidines 11. Twenty‐seven compounds of types 10 and 11 have been evaluated in the writhing, hot plate and kaolin tests; especially the cis‐pyrrolidines 10 exhibit a valuable antinociceptive activity. Some of the pyrrolines and pyrrolidines have been separated into their enantiomers, which are easily interconverted.
Natural Abundance17O‐NMR. Study of Some Macrocyclic Complexes with Alkali Metal Cations
Authors: Popov Alexander I. , Smetana Alfred J. , Kintzinger Jean‐Pierre , Nguyêen Thi Thanh‐Tâam
Published: December 2004

Complexation between crown ethers 12C4, 15C5, 18C6 and cryptand 222, and alkali cations Li+, Na+, K+in various solvents were studied by17O‐NMR. spectroscopy. Small diamagnetic shifts arising from the cation electric field are observed. They increase according to the sequence K+< Na+< Li+.17O‐linewidth are discussed and compared to the13C relaxation times. Linewidth modification results mainly from modifications of the effective correlation time. In general, for crown ethers, considerable line broadening occurs when the cation fits well into the cavity but line narrowing occurs when the cation is much smaller than the cavity.
Complete Racemization in the Base Hydrolysis of Optically Active mer‐[Chloro(diethylene triamine) (1,3‐diaminopropan‐2‐ol‐N,N′) cobalt (III)]tetrachlorozincate
Authors: Comba Peter , Marty Werner
Published: December 2004

The base hydrolysis of the optically active title compound proceeds with full racemization whilst the meridional arrangement of the diethylenetriamine ligand is fully retained. The optically active hydroxo complex prepared independently with retention of configuration racemizes ≳ 104 times slower. This unique result is discussed in terms of the classical π‐stabilization hypothesis for the base hydrolysis mechanism.
Stereospezifische 1,2‐Wanderungen von Hydroxyl‐, Aryl‐ und Alkyl‐ gruppen bei der Nitrosierung von Aminosäuren in Fluorwasserstoff/Pyridin. Vorläufige mitteilung
Authors: Keck Rolf , Rétey János
Published: December 2004

Stereospecific 1,2‐Migration of Hydroxyl, Aryl and Alkyl Groups during the Nitrosation of Amino Acids in Hydrogenfluoride/Pyridine Vorläufige Mitteilung

The nitrosation of α‐amino acids in hydrogenfluoride/pyridine was reinvestigated. In contrast to recent reports [1] [2] it was found that this reaction takes place either with entire (phenylalanine, tyrosine, threonine) or partial (valine, isoleucine) rearrangement to yield β‐fluorocarboxylic acids. Glycine, alanine and α‐aminobutanoic acid were converted exclusively into the α‐fluorocarboxylic acids. The substitution of the amino group takes place with stereochemical retention as revealed by NMR. examination of the 2‐fluoro‐3‐methylpentanoic acids obtained from L‐isoleucine and D‐alloisoleucine, respectively.
Synthesis of Tricyclo [6.2.1.01,5]undecadiones via Intramolecular Photoaddition of 5‐(1‐Cyclopentenylmethyl)‐3‐alkoxy‐2‐cyclopentenones
Authors: Oppolzer Wolfgang , Burford Sidney C.
Published: December 2004

Irradiation of the dienone methyl ether 3a furnished the unstable regioisomeric photoadducts 4a and 5a which on Lewis acid‐catalyzed fragmentation afforded the tricyclic diketones 6,7 and 8. The same mixture was obtained from the isobutyl ether 3b (Scheme 2).
Die Synthese von 6exo‐substituierten p‐Toluolsulfonsäure‐[2exo‐norbornyl]estern. Norbornanreihe, 1. Mitteilung
Authors: Fischer Walter , Grob Cyril A. , Von Sprecher Georg
Published: December 2004

The Synthesis of 6exo‐Substituted 2exo‐Norbornyl p‐Toluenesulfonates

A number of hitherto unknown 6exo‐substituted 2exo‐norbornanols and their p‐toluenesulfonates have been prepared by functionalization of intermediate norbornenes.