bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photochemische und nicht‐photochemische A/D‐Secocorrin→Corrin‐Cyclisierungen bei 19‐Carboxy‐ und 19‐Formyl‐1‐methyliden‐1,19‐secocorrinaten. Decarboxylierbarkeit und Deformylierbarkeit von Nickel (II)‐19‐carboxy‐ bzw. 19‐formyl‐corrinaten. Vorläufige Mitteilung
Authors: Pfaltz Andreas , Bühler Niklaux , Neier Reinhard , Hirai Koichi , Eschenmoser Albert 
Published: December 2004

Photochemical and non‐photochemical A/D‐secocorrin→corrin‐cyclizations of 19‐carboxy‐ and 19‐formyl‐1‐methylidene‐1,19‐secocorrinates. Decarboxylation (and deformylation) of nickel(II)‐19‐carboxy‐(resp. 19‐formyl)‐corrinatesNickel (II) 1‐methylidene‐2,2,7,7,12,12‐hexamethyl‐15‐cyano‐19‐carboxy‐1,19‐secocorrinate can be induced to cyclize with concomitant decarboxylation to the corresponding corrinate (Scheme 9). Experiments with deuterated derivatives (Scheme 10) indicate that in this decarboxylative A/D‐secocorrin→corrin‐cyclization the ring closure step precedes decarboxylation. In accord therewith is the finding that the corresponding intermediate nickel(II) 19‐carboxy‐corrinate (synthesized via photochemical cyclization of the corresponding cadmium complex, Schemes 6 and 9) decarboxylates under very mild conditions.Nickel(II) 1‐methylidene‐2,2,7,7,12,12‐hexamethyl‐15‐cyano‐19‐formyl‐1,19‐secocorrinate cyclizes smoothly to the corresponding 19‐formyl‐corrinate in the presence of acetic acid/triethylamine. The formyl group of the cyclization product can be eliminated hydrolytically in essentially quantitative yield by treatment with 2N KOH in ethanolic solution (Scheme 11). The non‐photochemical (A→D)‐cyclization of 19‐formyl‐1,19‐secocorrinoids represents formation of the corrin chromophore at the oxidation level of porphyrinogens and exemplifies how a C1‐fragment that eventually leaves the ligand can fulfill a specific function in the (A→D)‐ring closure to a corrin.
Adducts of Niobium (V) and Tantalum (V) Halides. XV. Ligand Exchange of the Adducts with Some Phosphoryl Compounds
Authors: Favez Christian M. P. , Merbach André E. 
Published: December 2004

AbstractThe ligand exchange MX5·L + *L⇌MX5·*L + L for the octahedral adducts MX5·L, in an inert solvent (CH2Cl2 or CHCl3) with neutral ligands, proceeds via a dissociative D mechanism when M = Nb, X = Cl and L = phosphoryl compound. A dissociative interchange Id mechanism is suggested when M = Nb or Ta, and X = F. A first order rate law and positive values for ΔS* (+4 to +14 cal K−1 mol−1) are observed for the exchanges on the pentachloride adducts. However, a second order rate law and large negative values for ΔS* (‐15 to ‐24 cal K−1 mol−1) are found for the intermolecular neutral ligand exchange (measured by 1H‐NMR.) and for the intramolecular fluorine exchange (measured by 19F‐NMR.) reactions on the pentafluoride adducts. The fluorine exchange is 2 to 5 times faster than the ligand exchange. The exchanges, on the pentachloride and on the pentafluoride adducts, are slowed down with increasing donor strength of the phosphoryl compound.
Diterpenoide Drüsenfarbstoffe aus Labiaten: Coleone U, V, W und 14‐O‐Formyl‐coleon‐V sowie 2 Royleanone aus Plectranthus myrianthus BRIQ.; cis‐ und trans‐A/B‐6, 7‐Dioxoroyleanon
Authors: Miyase Toshio , Rüedi Peter , Eugster Conrad Hans 
Published: December 2004

Leaf‐gland Pigments: Coleons U, V, W, 14‐O‐Formyl‐coleon‐V, and two Royleanones from Plectranthus myrianthus BRIQ.; cis‐ and trans‐A/B‐6,7‐DioxoroyleanonesFrom leaf‐glands of the South‐African P. myrianthus (Labiatae) the following diterpenoids have been isolated and their structures established: coleon U, C20H26O5 (6, 11, 12, 14‐tetrahydroxy‐abieta‐5, 8, 11, 13‐tetraene‐7‐one, 2a); coleon V, C20H26O5 (11, 12, 14‐trihydroxy‐abieta‐8, 11, 13‐triene‐6, 7‐dione, 4a); coleon W, C22H28O8 (16(or 17)‐acetoxy‐6, 11, 12, 14, 17 (or 16)‐pentahydroxy‐abieta‐5, 8, 11, 13‐tetraene‐7‐one, 6); 14‐O‐formyl‐coleon‐V, C21H26O6 (14‐formyloxy‐11, 12‐dihydroxy‐abieta‐8, 11, 13‐triene‐6, 7‐dione, 4b); 7α‐formyloxy‐6β‐hydroxyroyleanone, C21H28O6 (7α‐formyloxy‐6β, 12‐dihydroxy‐abieta‐8, 12‐diene‐11, 14‐dione, 1a); the already known 6β, 7α‐dihydroxyroyleanone (1c) and a dimeric abietane derivative whose structure is not yet elucidated. This is the first record of a co‐occurrence of coleons and royleanones in the same plant. In the course of chemical investigations of 4a and 4b the highly oxidized trans‐ and cis‐A/B‐6,7‐dioxoroyleanones (5a and 5b) were obtained.
Transition‐metal complexes with bidentate ligands spanning trans‐positions. V. Crystal and molecular structures of complexes [RhCl(CO) (1)] and [PdCl2(1)]; 1 = 2,11‐bis (diphenylphosphinomethyl)benzo [c]phenanthrene
Authors: Bachechi Fiorella , Zambonelli Luigi , Venanzi Luigi M. 
Published: December 2004

AbstractThe structures of [RhCl(CO) (1)] and [PdCl2 (1)], where 1 is the bidentate ligand (C6H5)2P·CH2·C18H10· CH2·P(C6H5)2, have been determined from threedimensional X‐ray counter data collected on single crystals of the C6H5·CN solvates. The two compounds are isomorphous and crystallize in the triclinic system, space group P 1, Z = 2: a = 14.580 (8), b = 13.029 (10), c = 11.909 (6) Å, α = 106.33 (5), β = 100.47 (4), γ = 95.73 (5)° for the rhodium complex; a = 14.361 (5), b = 13.044 (7), c = 11.897 (4) Å, α = 105.97 (4), β = 100.27 (3), γ = 94.76 (4)°, for the palladium complex. In both complexes the metal atom is four‐coordinate with slightly distorted square‐planar configuration. In both cases the ligand 1 spans trans positions with M‐P bond lengths in the ranges of the literature data. Also the other bond distances fall in regular ranges. Ligand 1 has almost the same conformation in both complexes and is characterized by a strong out‐of‐plane deformation of the benzophenanthrene system as a consequence of severe overcrowding.
Synthese von radioaktiv markierten Bromacetyl‐ und Diazoacetyl‐α‐melanotropin‐Derivaten zum Studium von kovalenten Hormon‐Makromolekül‐Komplexen
Authors: Eberle Alex , Hübscher Willy , Schwyzer Robert 
Published: December 2004

Synthesis of radioactive α‐melanotropin derivatives containing a bromoacetyl or diazoacetyl group for studies of covalent hormone‐macromolecule complexesα‐Melanotropin derivatives and fragments covalently bound to human serum albumin through their N‐terminal end exhibit almost the same biological activity as the corresponding free Nα‐acetylated peptides [6]. The preparation of such complexes requires derivatives with a ‘reactive’ N‐terminal acetyl group. We describe here the synthesis of three α‐melanotropin fragments and of two specifically tritiated α‐melanotropin derivatives containing Nα‐bromoacetyl or Nα‐diazoacetyl groups: BrCH2CO · Glu‐His‐Phe‐Arg‐Trp‐Gly‐Lys‐Pro‐Val · NH2, BrCH2CO · Glu‐His‐Phe‐Arg‐Trp‐Gly · OH, BrCH2CO · Trp‐Gly‐Lys‐Pro‐Val middot; NH2, BrCH2CO · D‐Ala‐Tyr(3H2)‐Gly‐Nva‐Glu‐His‐Phe‐Arg‐Trp‐Gly‐Lys‐Pro‐Val · NH2, and N2 = CHCO · Gly‐Tyr(3H2)‐Ser‐Nva‐Glu‐His‐Phe‐Arg‐Trp‐Gly‐ Lys‐Pro‐Val · NH2. The latter two analogues displayed a specific radioactivity of about 20 and 36 Ci/mmol, and a biological activity of 2 · 109 and 6 · 109 U/mmol respectively. They are also being used for affinity and photoaffinity labelling of receptor molecules and antibody combining sites.
Chemical selectivities disguised by mass diffusion. III. A comparison of two versions of a simple model of mixing‐disguised reactions in solution. 3rd communication on the selectivity of chemical processes
Authors: Nabholz Felix , Ott Roland J. , Rys Paul 
Published: December 2004

AbstractA simple mixing‐reaction model has been developed [1] which allows a description and simulation of the coupling of the mass diffusion with the chemical reaction during the mixing process of two miscible reactant solutions. For competitive, consecutive as well as for competitive, parallel second‐order reactions the general behaviour and the dependence of the product distribution on diffusion effects are calculated for semi‐continuous reaction conditions using various simplifying assumptions. The usefulness of these assumptions is discussed with reference to the calculated predictions of two versions of the mixing‐reaction model.
Synthesen und Thermolysen von 1‐Alkinyl‐2‐methyl‐1,2‐epoxy‐cycloalkanen. ‐ Versuche zur Ringerweiterung um drei Kohlenstoffatome
Authors: Karpf Martin , Dreiding André S. 
Published: December 2004

Syntheses and Thermolyses of 1‐Alkynyl‐2‐methyl‐1,2‐epoxy‐cycloalkanes. ‐ Attempts at Ring Enlargement by Three Carbon AtomsThe 1‐alkynyl‐2‐methyl‐1,2‐epoxy‐alkene 2 and ‐cycloalkenes 9, 28 and 29 were obtained by epoxidation of the conjugated en‐ynes 1, 7, 26 and 27. The 12‐membered ring en‐ynes 26 and 27 were synthesized by ethynylation or propynylation of 2‐methylcyclododecanone (19) to the 1‐ethynyl‐ or 1‐(1′‐propynyl)‐cyclododecanols 20 A/B and 21 A/B, respectively, followed by dehydration to give separable mixtures of the regio‐ and stereoisomeric en‐ynes 22, 24, 26 and 23, 25, 27, respectively.Gas‐phase thermolyses of the epoxides 2, 9, 28 and 29 were carried out under reduced pressure through a quartz tube at 550–600°. The formation of 5‐hexine‐2‐one (3) and 4,5‐hexadien‐2‐one (4) from 2 can be explained by [1, 5]‐ and [1, 3]‐ hydrogen shifts, respectively, and subsequent Claisen‐type rearrangements. Thermolysis of the six‐membered carbocyclic epoxide 9 induced the expected ring expansion by three carbon atoms to give 14% 4‐cyclononynone (12), along with the ketones 13, 14 and 15 as by‐products, which probably arose from surface induced heterolytic C, O‐bond fission and Wagner‐Meerwein‐type rearrangement processes.Preliminary experiments with the thermolysis of the 12‐membered carbocyclic ethynyl‐epoxide 28, yielded a mixture, which contained 4‐cyclopentadecynone (30) and afforded, after hydrogenation, cyclopentadecanone (31, exaltone®) in 36% yield as the semicarbazone. Traces of 3‐methylcyclopentadecanone (32, rac, ‐muscone) were identified after thermolysis and hydrogenation of the propynyl‐epoxide 29.
Synthèse partielle de la (20S)‐ψ‐vincamine et de la (20S)‐épi‐16ψ‐vincamine
Authors: Le Men Jean , Caron‐Sigaut Catherine , Hugel Georgette , Le Men‐Olivier Louisette , Lévy Jean 
Published: December 2004

Partial Synthesis of (20S)‐ψ‐Vincamine and (20S)‐epi‐16ψVincamineAn attempt of classification of the indole alkaloids is presented; (20S)‐ψ‐vincamine. (20S)‐16‐épi‐ψ‐vincamine and (20S)‐ψ‐apo‐vincamine have been prepared from catharanthine by partial synthesis.
Kristalline und molekulare Struktur von N‐Isopropyl‐7endo‐phenyl‐5,9‐methano‐6,7,8,9‐tetrahydro‐5 H‐benzo‐cyclohepten‐6exo‐yl‐amin
Authors: Weber Hans Peter , Petcher Trevor James 
Published: December 2004

Crystal and Molecular Structure of N‐Isopropyl‐7endo‐phenyl‐5,9‐methano‐6,7,8,9‐tetrahydrobenzocyclo‐hepten‐6exo‐yl‐aminThe structure of the title compound was determined by X‐ray analysis of its hydrochloride. Space group Iba2, a=32.58, b=15.55, c=7.30 Å. The structure was refined by LS‐methods with 718 significant data to R=0.053.
Über die Carotinoide Flavoxanthin und Chrysanthemaxanthin: 1H‐NMR.‐, 13C‐NMR.‐ und Massen‐Spektren und absolute Konfiguration. (Kritische Überprüfung veröffentlichter chemischer und physikalischer Daten)
Authors: Cadosch Herbert , Vögeli Ulrich , Rüedi Peter , Eugster Conrad Hans 
Published: December 2004

On the Carotenoids Flavoxanthin and Chrysanthemaxanthin: 1H‐NMR., 13C‐NMR. and Mass Spectra, Absolute Configuration, Survey of Published DataVery pure flavoxanthin (1) and chrysanthemaxanthin (2) have been reisolated from flower heads of Taraxacum officinale. Both compounds were characterized by chromatographic, chemical and chiroptical data and extensive NMR. measurements. Examination of many published data on 1 and 2 led to the conclusion that flavoxanthin has often been mistaken for chrysanthemaxanthin and vice versa.Chemical degradation of 1 and 2 to (−)‐loliolide (5) coupled with NMR. evidence (ASIS, spin‐decoupling, NOE) allowed the assignment of the absolute configurations of 1 and 2. Thus (+)‐flavoxanthin is (3S,5R,8R, 3′R,6′R)‐5, 8‐epoxy‐5, 8‐dihydro‐β, ε‐carotene‐3, 3′‐diol and (+)‐chrysanthemaxanthin its C(8)‐epimer.
Hexakis (methylidene)‐cyclohexane (“[6]Radialene”). Chemical and spectral properties
Authors: Schiess Peter , Heitzmann Markus 
Published: December 2004

AbstractUpon flash pyrolysis between 580 to 660°, 2,4,6‐tris(chloromethyl)mesitylene (2) leads to products formed through the loss of one, two and three molecules of HCl. The highly reactive chlorine free product is shown to be [6]radialene (1) both by its chemical reactions and by its spectral properties.
Struktur und Reaktivität eines Triazolobenzodiazepin/Oxalylchlorid‐Addukts
Authors: Heckendorn Roland , Gagneux André R. 
Published: December 2004

Structure and Reactivity of a Triazolo‐benzodiazepine/Oxalyl Chloride AdductReaction of oxalyl chloride with N, N‐dimethyl‐{8‐chloro‐6‐(0‐fluorophenyl)‐ 4H, 11 H‐[1,2,4]triazolo [1,5‐α] [1,4]benzodiazepine}‐2‐carboxamide (6a), the syn‐thesis of which is described, leads to the cyclic adduct N, N‐dimethyl‐{2,12,12‐trichloro‐13a‐(0‐fluorophenyl)‐11‐oxo‐10,11,12,13a‐tetrahydro‐5H, 9H‐[1,3]oxazolo [3,2‐d] [1,2,4]triazolo [1,5‐a] [1,4]benzodiazepine}‐7‐carboxamide (7a). Upon thermolysis 7a is partly reconverted to the starting diazepine 6a via loss of the elements of oxalyl chloride. Reduction of 7a with sodium borohydride also yields 6ain addition to its dihydro derivative 9. Energetic treatment of 7a with sodium methoxide leads to the unexpected methoxydiazepines 10a and 10b, and mild treatment of 7a with sodium methoxide to the stereoselective formation of the two precursors of 10, namely the chloromethoxy derivative 11 and the dimethoxy derivative 12. Epimerization of 11 followed by nucleophilic substitution gives a mixture of two dimethoxy compounds, 12 and its epimer 14. The configurational assignments of these derivatives are based upon X‐ray analysis of 12. A possible pathway for this unexpected substitution reaction is proposed.
On the Calculation of the Electronic Reorganization of Canonical and Localized Koopmans' Ions
Authors: Jungen Martin 
Published: December 2004

AbstractConditions and implications for the calculation of self‐consistent single determinant wave functions for Koopmans' ions are discussed and a recipe for practical computations is given. The concept of Koopmans' ions has been extended to localized ions and a definition for their reorganization energies is proposed. Calculations on formaldehyde serve as a numerical illustration.
1H‐ und 13C‐NMR.‐spektroskopische Untersuchungen an den vier diastereomeren (±)‐Dihydropalustraminsäure‐methylestern; Strukturkorrelation mit (−)‐Dihydropalustraminsäure‐methylester sowie mit dem Alkaloid Palustrin. 14. Mitteilung über Schachtelhalmalkaloide
Authors: Rüedi Peter , Eugster Conrad Hans 
Published: December 2004

1H‐and13C‐NMR. spectra of methyl esters of the diastereomeric (±)‐dihydropalustramic acids; structural correlation of (−)‐dihydropalustramic acid with the alkaloid palustrinUnambiguous assignment of cis‐trans configuration at the piperidine ring of the four diastereomeric methyl esters of the (±)‐dihydropalustramic acids is based on the interpretation of 1H‐ and 13C‐NMR. data. (−)‐Dihydropalustramic acid, the important degradation product of the alkaloid palustrin is shown to be threo‐cis‐[6‐(1‐hydroxypropyl)‐2‐piperidyl]acetic acid. The same conclusion holds for palustrin and dihydropalustrin. Therefore, palustrin is threo‐cis‐17‐(1‐hydroxy‐propyl)‐1,5,10‐triazabicyclo[11.4.0]heptadec‐15‐en‐11‐one.
Absolute Konfiguration der Equisetumalkaloide (+)‐Palustrin, Palustridin ((+)‐Monohydrochlorid) sowie der (−)‐Dihydropalustraminsäure und weiterer Derivate. 16. Mitteilung über Schachtelhalmalkaloide
Authors: Wälchli Peter Christian , Mukherjee‐Müller Gabriele , Eugster Conrad Hans 
Published: December 2004

Determination of the absolute configuration of alkaloids from Equisetum sp.,e.g. (+)‐palustrin, palustridin ((+)‐hydrochloride), and (−)‐dihydropalustramic acid and derivativesThe absolute configuration of the title alkaloids has been determined using chiroptical methods (ORD., superposition of CD. values of appropriate models and a modified Horeau method). (+)‐Palustrin is (13R, 17 S, 1′S)‐17‐(1‐hydroxypropyl)‐1,5,10‐triazabicyclo [11.4.0]heptadec‐15‐en‐11‐on.
Synthese von threo‐cis/threo‐trans‐ und erythro‐cis/erythro‐trans‐Dihydropalustrin. 17. Mitteilung über Schachtelhalmalkaloide
Authors: Wälchli‐Schaer Elisabeth , Eugster Conrad Hans 
Published: December 2004

Synthesis of threo‐cis/threo‐trans‐ and erythro‐cis/erythro‐trans‐dihydropalustrinThe first synthesis of a threefold protected spermidine, namely 3‐benzyloxycarbonyl‐N1‐phthaloyl‐N2‐tosylspermidin (9) is presented. Each of the protecting groups can be removed selectively. After hydrazinolysis the resulting N3‐benzyloxy‐carbonyl‐N2‐tosylspermidine (10) has been condensed with methyl (2 E)‐cis‐7,8‐epoxy‐2‐decenoate to the threo‐cis/trans piperidines 17, and with methyl (2 E)‐trans‐7,8‐epoxy‐2‐decenoate to the erythro‐cis/trans piperidines 17, respectively. After catalytic removal of the Z group, the resulting aminoesters 13 and 18, in a melt with imidazole, underwent ring closure to the 13‐membered lactames 14 and 19, respectively. reductive deprotection of the N‐tosyl group with sodium/ammonia led to the stereoisomeric palustrines 15 and 20, respectively.
Infrared and Raman spectroscopic studies of benzothiazolinic spiropyrans and merocyanines
Authors: Guiliano Michel , Davin‐Pretelli Eliane , Mille Gilbert , Chouteau Jacques , Guglielmetti Robert 
Published: December 2004

AbstractLes spectres IR. de cinq spiropyrannes benzothiazoliniques (ét solide et dissous) et les spectres Raman de trois d'entre eux (état solide) ont été enregistrés de 4000 à 400 cm−1 et ont permis une interprétation des vibrations moléculaires de ces composés. Une analyse plus sommaire, faite dans le but de caractériser la structure spiropyrannique a été étendue au moyen de la spectroscopie IR. à une série de vingt et un composés. L'étude IR. a également porté sur deux mérocyanines. Nous avons analysé et essayé d'interpréter les principales perturbations spectrales observées lors du passage d'un composé spiropyrannique (forme fermée) à la forme ouverte.
Anti‐ and syn‐Tricyclo [4.2.1.12,5]decane. Preliminary communication
Authors: Ernst Beat , Ganter Camille 
Published: December 2004

AbstractThe two novel tricyclic C10H16 compounds anti‐ and syn‐tricyclo [4.2.1.12,5]‐ decane (16 and 17, respectively) were synthesized starting either from the photodimer 2 (anti) or the two cycloaddition products 8 (anti) and 9 (syn).
Vitispiranes, Important Constitutents of Vanilla Aroma
Authors: Schulte‐Elte Karl H. , Gautschi Fritz , Renold Walter , Hauser Arnold , Fankhauser Peter , Limacher Josef , Ohloff Günther 
Published: December 2004

AbstractThe preparation of the vitispiranes 9 and 10, identified among the volatiles of vanilla, from the theaspiranes 1 and 2 via the intermediates 4 and 5 and the allyl alcohols 7 and 8, respectively, is described. The theaspiranes 1 and 2 can be obtained from the compounds 11–15 or 24–26.
A Di‐π‐Methane Rearrangement in the Photolysis of a 4‐Oxa‐steroidal α,β‐Unsaturated Enol‐lactone. Photochemical reactions VIII
Authors: Vallet José Alberto , Boix José , Bonet Juan‐Julio , Briansó Marie Claire , Miravitlles Carlos , Briansó José Luis 
Published: December 2004

AbstractThe irradiation of 17β‐acetoxy‐4‐oxa‐1,5‐androstadien‐3‐one (12) yielded the two stereoisomeric spiro‐lactones 13 and 14, which result from a di‐π‐methane photorearrangement. A third product, the oxa‐anthrasteroid 15, was also isolated (Scheme 3).
Photochemical Behaviour of 17β‐Acetoxy‐4‐aza‐1,5‐androstadien‐3‐one: Photo‐oxidation vs. Di‐π‐methane Rearrangement
Authors: Vallet José Alberto , Cánovas Antonio , Boix José , Bonet Juan‐Julio 
Published: December 2004

AbstractThe irradiation of the title compound 6 with UV. light and under photosensitized oxidation conditions yields products which are characteristic of the photo‐oxidation of the enamide moiety of 6. In contrast to the situation encountered in the case of the irradiation of its carbocyclic and 4‐oxa analogues 1 and 2, respectively, no compound resulting from a di‐π‐methane rearrangement of the Δ1,5(6)‐unsaturated system of 6 has been so far detected.
Photoelectron Spectra of Unsaturated Oxides. I. 1,4‐Dioxin and related systems
Authors: Bloch Martin , Brogli Franz , Heilbronner Edgar , Jones Taylor B. , Prinzbach Horst , Schweikert Otto 
Published: December 2004

AbstractThe He (Iα) photoelectron spectra of the four unsaturated oxides 3,4‐dihydropyran (6), γ‐pyran (7), 2, 3‐dihydro‐1, 4‐dioxin (9) and 1, 4‐dioxin (10) are reported and analysed. Band assignments are based on ab‐initio calculations, using the STO‐3G basis set. The proposed orbital sequences (with reference to the coordinate systems given in Table 1) are, for the top three orbitals: 6, π, nσ, nπ; 7, 3b1(π), 1a2(π), 11a1(σ); 9, 11b(π), 12a(σ), 11a(π); 10, 2b3u(π), 1b1g(π), 6ag(σ). Finally the (almost) localized π‐orbitals have been computed by the Foster‐Boys localization procedure.
Electrical Properties and Structure of the Organic Metallic Compound bis (tetraselenotetracene)‐iodide, (TSeT)2‐I
Authors: Hilti Bruno , Mayer Carl W. , Rihs Grety 
Published: December 2004

AbstractThe preparation of the new organic metallic compound (TSeT)2‐I is reported. The crystal structure of the free donor, TSeT, is discussed and compared with the crystal structure of (TSeT)2‐I. The latter has the orthorhombic space group P21212 and hence is not isomorphous with the analogous compounds (TSeT)2‐Cl and (TSeT)2‐Br, described by Shchegolev et al. [4].In contrast to those complexes (TSeT)2‐I consists of only one set of crystallographically equivalent chains and therefore its transition to the low‐temperature conducting state (Fig. 6) is also of different type.The d. c. resistivity at 300 K ranges from 10−3 to 1.5 ·. 10−4 Ω cm. The temperature dependence of the d.c. resistivity of the title compound is given: in the temperature range from 300 to 80 K the normalized d.c. resistivity is described by ρ(T)/ρ(300) ∝ T1.7. Between 80 and 70 K a slight deviation from the above law has been detected which is taken as an indication of a phase transition; its nature is, however, not yet definable. The low‐temperature conducting state reached at about 70 K shows an almost constant resistivity in the interval 60 K to 45 K. Its normalized d.c. resistivity in the range 4.5 K‐50 K is described by ρ(T)/ρ(300) ∝ (T−Tm)3, with Tm = 50 K. The value of the normalized resistivity extrapolated to O K is 0.75.
Makrocyclische und acyclische neutrale Ionophore. Einfluss des Ringschlusses auf die Kationenselektivität
Authors: Bissig René , Pretsch Ernö , Morf Werner E. , Simon Wilhelm 
Published: December 2004

Macrocyclic and noncyclic neutral ionophores. Effect of the macrocyclic ring on the ion selectivityA series of macrocyclic 3, 6‐dioxaoctanedioic diamides was prepared. Their ion selectivity in membranes was compared with nonmacrocyclic analogues. The ion selectivity as well as the capability to extract ions from aqueous solutions to an organic phase decreases with decreasing ring size.
Additionsreaktionen an der alicyclischen Doppelbindung von Eburnamenin und Apovincamin
Authors: Pfäffli Paul , Hauth Hartmut 
Published: December 2004

Addition reactions on the alicyclic double bond of eburnamenine and apovincamineThe addition of alcohols, amines or thiols on the 14, 15‐double bond of (−)‐eburnamenine (3a) or (+)‐apovincamine (9a) yielded the corresponding analogues of vincanol (5b‐h), epivincanol (7b‐d), vincamine (10b‐e) and epivincamine (11b‐g) with varying stereoselctivity. The reaction was achieved by addition of hydrogenbromide at −78° followed by nucleophilic attack, or in the (−)‐eburnamenine series also by direct addition of alcohols and thiols under acidic conditions. Without exception the analogues of epivincamine (11a‐g) exhibited two carbonyl absorption bands in thier IR. spectra. (−)‐Eburnamenine (3a) was obtained from (+)‐apovincamine (9a) in a simple one pot reaction.