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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 77 (1994), S. 1611-1615 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Formation, X-Ray Crystal Structure, and Absolute Configuration of (-)-N-(Chloromethyl)galanthaminium ChlorideThe acetylcholinesterase inhibitor galanthamine (1), main alkaloid of several Narcissus species, readily forms a quaternary ammonium salt by reaction with the solvent CH2Cl2. The structure and absolute configuration of (-)-N-(chloromethyl)galanthaminium chloride (2) were determined by X-ray diffraction (R = 0.075 for 2775 observed independent reflexions) and NMR spectroscopy. The tetragonal crystals (space group P43) contain two crystallographically independent cations which do not differ significantly from one another. The CH2Cl group is attached to the quaternary N-atom in stereospecific (R)-configuration. In the crystal, the configurational position of the Me group at the N-atom of 2 differs from that of the crystalline free base 1. Hydrogen bonding is observed from the OH group at C(3) of 2 to the Cl- anion or to the Cl-atom of an adjacent cation.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1984 (1984), S. 306-318 
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Intramoleclar Addition of Carbanions to AnthraquinonesThe intramolecular Michael addition of the carbanions derived from the β-keto diesters 15a and 15b yields the naphthacenequinones 20a and 20b. In contrast, the similar dimethyl ether 11 cyclizes to give the benzo[α]anthracenequinone 17. The hydroquinone of 1,8-dihydroxyanthraquinone (5a) reacts with acrylate to yield the unusual anthrone derivatives 12b and 12c.
    Notes: Die intramolekulare Michael-Addition der Carbanionen, die sich von den β-Ketodiestern 15a und 15b ableiten, liefert die Naphthacenchinone 20a und 20b. Dagegen cyclisiert der Dimethylether 11 zum Benzo[α]anthracenchinon 17. Das Hydrochinon des 1,8-Dihydroxyanthrachinons (5a) reagiert mit Acrylsäureester zu den ungewöhnlichen Anthron-Derivaten 12b und 12c.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Einwirkung von Perjodat auf Dextran, Xylan, Inulin und Saccharose führt zu Oxydationsprodukten dieser Zucker, die mit Phenylhydrazin unter anderem Abkömmlinge der Rubazonsäure ergeben.  -  Die gleichen Verbindungen entstehen bei Einwirkung von asymmetrisch disubstituierten Arylhydrazinen auf D-Fructoson-1-phenylhydrazon oder auf Glycerose-phenylosazon und durch Umsetzung von Glycerinaldehyd-methylphenylhydrazon mit Phenylhydrazin. Es wird über Synthese und Eigenschaften dieser Verbindungen berichtet.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 500-506 
    ISSN: 0044-2313
    Keywords: Polytellurido Complexes of Zinc and Mercury ; Synthesis ; Crystal Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal Structures of the Polyellurido Complexes [K(15-Crown-5)2]2[MTe7] with M = Zn and HgThe title compounds were obtained in the presence of 15-crown 5 from solutions of zinc and mercury acetate, respectively, in DMF by addition of a solution of K2Te3 in DMF at 0°C (M = Zn) and -50°C (M = Hg). They form black crystal needles with metallic luster. Their crystal structures were determined by X-ray diffraction. The structures of [K(15-crown-5)2]2ZnTe7 and [K(15-crown-5)2]2HgTe7 show two-dimensional disorder as evidence by diffuse scattering. The averaged structures that were determined with the Bragg reflexions correspond to space group Pbcn and have very similar lattice parameters. Nevertheless, the structures differ. [HgTe7]2- ions consist of two condensed five membered rings. They are arranged to form strands in the c direction; within of one strand the ions have a definite orientation, but in different strands two different orientations occur randomly. A [ZnTe7]2- ion can be thought of consisting of a Zn2+ ion, a Te42- ion bonded in a chelate manner and a Te32- ion bonded with one terminal Te atom to the Zn2+. The [ZnTe7]2- ions are associated to strands in the c direction with two different strand orientations occuring randomly.
    Notes: Die Titelverbindungen entstehen aus Lösungen der Acetate von Zink bzw. Quecksilber in DMF bei Anwesenheit von 15-Krone-5 nach Zugabe einer Lösung von K2Te3 in DMF bei 0°C (M = Zn) bzw. -50°C (M = Hg). Die Verbindungen bilden schwarze, metallisch glänzende Kristallnadeln, die wir durch röntgenographische Strukturanalysen charakterisiert haben. Die Kristallstrukturen von [K(15-Krone-5)2]2[ZnTe7] und [K(15-Krone-5)2]2[HgTe7] sind zweidimensional fehlgeordnet, wie die entsprechende diffuse Streuung zeigt. Die Überlagerungsstrukturen, die mit Hilfe der Braggschen Reflexe bestimmt wurden, entsprechen bei beiden Verbindungen der Raumgruppe Pbcn bei sehr Ähnlichen Gitterparametern. Trotzdem unterscheiden sich die Strukturen. Die [HgTe7]2--Ionen bestehen aus zwei kondensierten Fünferringen. Sie sind zu Strängen längs c angeordnet, wobei sie innerhalb eines Stranges eine definierte Orientierung haben, aber von Strang zu Strang eine von zwei entgegengesetzten Orientierungen statistisch vorkommt. Ein [ZnTe7]2--Ion kann man sich aufgebaut denken aus einem Zn2+-Ion, einem chelatartig gebundenen Te42--Ion und einem Te32--Ion, das über ein terminales Te-Atom an das Zn2+ gebunden ist. Die [ZnTe7]2--Ionen sind zu Strängen längs c assoziiert, wobei statistisch zwei Strangorientierungen vorkommen.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 416-420 
    ISSN: 0044-2313
    Keywords: Nonaselenide ; Synthesis ; Crystal Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis and Crystal Structure of the Nonaselenide [Sr(15-crown-5)2]Se9The title compound was prepared by the reaction of excess selenium with strontium diselenide in DMF in the presence of 15-crown-5. [Sr(15-crown-5)2]Se9 forms black crystals, which are soluble in DMF. They were characterized by FIR spectroscopy and by an X-ray structure determination.Space group P21/n, Z = 4, 2 381 observed unique reflections, R = 0.073. Lattice dimensions at 19°C: a = 1 228.7, b = 1 893.4, c = 1 575.7 pm, β = 99.15°. The compound consists of [Sr(15-crown-5)2]2+ ions in which the strontium ion is coordinated by the oxygen atoms of the crown ether molecules in a sandwich-like fashion, and of Se92- ions with a chain structure, which has a topolocical resemblance with the bicyclic ion Se102-.
    Notes: Die Titelverbindung entsteht durch Einwirkung von überschüssigem Selen auf Strontiumdiselenid in Dimethylformamid (DMF) in Gegenwart von 15-Krone-5. [Sr(15-Krone-5)2]Se9 bildet schwarze, in DMF leicht lösliche Kristalle, die durch das FIR-Spektrum und eine röntgenographische Strukturanalyse charakterisiert werden.Raumgruppe P21/n, Z = 4, 2 381 beobachtete unabhängige Reflexe, R = 0,073. Gitterabmessungen bei 19°C: a = 1 228,7; b = 1 893,4; c = 1 575,7 pm, β = 99,15°. Die Verbindung besteht aus [Sr(15-Krone-5)2]2+-Ionen, in denen das Strontiumion sandwichartig von den O-Atomen der beiden Kronenethermoleküle umgeben ist, und kettenförmigen Se92--Ionen, die topologische Verwandtschaft zu dem bicyclischen Se102--Ion aufweisen.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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