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  • 1
    ISSN: 1434-4475
    Keywords: 3-Vinylindoles ; Cycloadducts ; 1H-NMR ; X-Ray analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The products2,3 of the reaction ofE/Z-1-benzenesulfonyl-3-(1-pentenyl)-indole (1) and N-phenylmaleimide were analysed by1H-NMR spectroscopy. Exemplarily, the structure elucidation of theendo-cyclo-adduct2 b was achieved by using several NMR techniques (diff. NOE-, INDOR-measurements, decoupling experiments, spectra simulation). The1H-NMR-spectroscopically gained prediction of relative configuration and conformation of2 b was supported on X-ray analysis. The cyclohexene ring of the new cycloadducts adopts in the liquid phase and in the crystal a slightly twisted boat conformation.
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  • 2
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,3-Dithienium and 1,3-Dithiolenium Salts. IX. Reactions of 1,3-Dithiane-2-ylium Tetrafluoroborates with C-Nucleophiles1,3-Dithian-2-ylium tetrafluoroborates (1), which can be easily obtained by variable methods, react in good to excellent yields with variable C-nucleophiles to new geminal disubstituted 1,3-dithianes. The latter compounds are potential precursors of interesting synthetic building blocks. Reactions are described with 2-lithio-1,3-dithianes 2, sodium cyanide 4, sodium salts of the nitro alkanes 7 and CH-acids of the type of the 1,3-dicarbonyl compounds 9. The reduction of 3-oxo-2-(2-phenyl-1,3-dithian-2-yl)-ethoxybutanoat-following a diastereoselective pathway - leads to the Cram product 11. Further presented is the crystal structure of 2-phenyl-1,3-dithiane-2-ylium tetrafluoroborate (1b).
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  • 3
    ISSN: 1434-193X
    Keywords: Colchicine ; 10-Ethylthiocolchicide, diene properties of ; π-Facial diastereoselectivity ; Consecutive [4+2],[3+2] cycloadditions ; Atropisomerism ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cycloaddition reactions of the facially dissymmetric diene moiety of (-)-(M,7S)-colchicine (5) and (-)-(M,7S)-10-ethylthiocolchicide (9) to various alkynes have been studied. With 5 and the dienophilic benzyne (3), dimethyl acetylenedicarboxylate (DMAD) (4) and cyclooctyne (6) as starting materials all cycloadditions could be realized with high regioselectivity at the 8,12-positions of the alkaloid. The approach of the dienophiles preferentially occurred toward the syn π-face of the diene. In contrast to the cycloaddition mode of 5 the ethylthiocolchicide 9 surprisingly reacted in a different manner. With benzyne as starting material a novel [3+2] cycloaddition of the thioenol ether moiety of 9 towards the dipolarophilic benzyne is supposed, affording the unexpected colchicide 10 after [1,5]H shift of the primarily formed cycloadduct followed by cleavage of the C-S linkage. With DMAD (4) and cyclooctyne (6) the reaction course is more complex. In a consecutive [4+2]/[3+2] cycloaddition (or vice versa) followed by a thermally induced cycloreversion of a not identified intermediate DMAD (4) gives rise to the polycyclic thiophene derivative 13 and the novel allocolchicinoid 14. In a similar way cyclooctyne (6) yielded three products, the thiophene-annulated homobarrelenones 18 and 19 and the tetracyclic allocolchicinoid 21. The structures of the novel colchicine derivatives were assigned on the basis of spectral data, those of the cycloadducts 1 and 19 were verified by X-ray crystallography. For the unprecedented formation of the various allocolchicinoids by consecutive [4+2]/[3+2] cycloadditions plausible reaction pathways are suggested, as far as possible. In addition the inhibitory effects on the tubulin polymerization reaction in vitro of 10, 14, and 21 are reported.
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  • 4
    ISSN: 0947-3440
    Keywords: Colchicine, diene properties of ; Positional selectivity ; Stabilized exciplex through hydrogen bonding ; π-Facial diastereoselectivity ; Photooxygenation ; Solvent effects ; Cycloadditions ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Positional and facial selectivity in Diels-Alder reactions of several hetero- and carbodienophiles with (-)-(aS,7S)-colchicine (1) has been examined. In all cases, cycloaddition occurred with high positional selectivity at the 8,12-positions of the alkaloid and preferentially from the diene face syn to the allylic substituent at the stereogenic center C-7. The observed high π-facial diastereoselectivity is independent of the polarity of the solvent used and is therefore probably a consequence of steric factors. The structures of the Diels Alder-adducts of 1 with singlet oxygen, N-phenyl-1,2,4-triazolinedione (PTAD) and trans-cyclooctene, 4,5, and 15, respectively, were assigned on the basis of spectral data and verified by X-ray crystallography.
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  • 5
    ISSN: 0044-2313
    Keywords: Crystal structure ; hydrates of ternary alkali/lanthanide(III) chlorides ; preparation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Rb3LnCl6 · 2 H2O (Ln = La—Nd): Preparation, Crystal Structure, and Thermal BehaviourThe compounds Rb3LnCl6 · 2 H2O (Ln = La—Nd) were prepared from acetic acid as powders. The preparation from aqueous solutions does not yield the pure products because RbCl precipitates as first compound. The structure of Rb3LaCl6 · 2 H2O was determined by X-ray analysis of a single crystal obtained from aqueous solution. The compounds with Ln = La—Nd are isotypic. They crystallize hexagonally in the space group P63/m (Rb3LaCl6 · 2 H2O: a = 1 220.4(2) pm, c = 1 688.6(3) (pm) with Z = 6. Anionic trimeric units [Ln3Cl12(H2O)6]3- are stacked along the c-axis over the corners of the unit cell. In the stacking frequency the units are rotated by 60° with respect to each other around the c-axis. The coordination number (C. N.) of Ln3+ is 8, which is satisfied by four bridging and two terminal chloride ions and two water molecules. The coordination spheres of the three rubidium ions in the different atomic positions are composed differently, their C.N. are 9, 8(+1) and 6(+6). The thermal dehydration of the compounds occurs in one step. The hydrates decompose at ca. 100°C to form the anhydrous compounds Rb2LnCl5 und RbCl since the anhydrous chlorides Rb3LnCl6 are thermodynamically stable above ca. 400°C only.
    Notes: Verbindungen Rb3LnCl6 · 2 H2O (Ln = La—Nd) lassen sich feinkristallin aus Eisessig als Lösungsmittel darstellen. Aus wäßriger Lösung lassen sich Einkristalle im Gemisch mit RbCl erhalten. An einem Einkristall von Rb3LaCl6 · 2 H2O wurde eine Strukturanalyse durchgeführt: Raumgruppe P63/m. a = 1 220,4(2) pm, c = 1 688,6(3) pm, Z = 6). Als anionische Teilstruktur liegen trimere Einheiten [Ln3Cl12(H2O)6]3- vor, die entlang der c-Achse über den Ecken der hexagonalen Elementarzelle gestapelt sind. In der Stapelfolge sind die Einheiten um jeweils 60° zueinander verdreht. Die Koordinationszahl (C. N.) des Ln3+ ist 8 und setzt sich aus vier verbrückenden und zwei terminalen Chloridionen sowie zwei Wassermolekülen zusammen. Die C.N. der drei Rubidiumionen auf nicht symmetrieäquivalenten Lagen betragen 9, 8(+1) und 6(+6). Die thermische Entwässerung der Verbindungen erfolgt in einem Schritt bei ca. 100°C unter Zerfall in Rb2LnCl5 und RbCl, da die wasserfreien 3:1 Verbindungen Rb3LnCl6 erst ab ca. 400°C stabil sind.
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  • 6
    ISSN: 0044-2313
    Keywords: Crown ether complex of antimony ; synthesis ; 121Sb-Mössbauer spectrum ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis, Crystal Structure, and 12Sb-Mössbauer Spectrum of [SbCl2(18-Crown-6)]+SbCl6-The title compound, which has been prepared by the reaction of antimony trichloride and antimony pentachloride in the presence of 18-crown-6 in acetonitrile solution, is characterized by its 121Sb-Mössbauer spectrum and by an X-ray structure determination. Space group P21, Z = 2, 2439 observed unique reflections, R = 0.045, wR = 0.043. Lattice dimensions at -80°C: a = 780.6(7), b = 1297.5(9), c = 1 278.5(10) pm, β = 100.56(7)°. The structure of [SbCl2(18-crown-6)]+SbCl6- contains cations in which the antimony atom in the first coordination sphere is surrounded in a φ-trigonal-bipyramidal fashion by two oxygen atoms of the crown ether in axial position as well as in the equatorial position by the two chlorine atoms and the lone electron pair.
    Notes: Die Titelverbindung entsteht aus Antimontrichlorid und Antimonpentachlorid in Gegenwart von 18-Krone-6 in Acetonitrillösung. Sie wird durch ihr 121Sb-Mößbauer-Spektrum und durch eine röntgenographische Strukturanalyse charakterisiert. Raumgruppe P21, Z = 2, 2439 beobachtete unabhängige Reflexe, R = 4,50%, wR = 4,25%. Die Gitterkonstanten betragen bei -80°C: a = 780,6(7); b = 1 297,5(9); c = 1 278,5(10) pm, β = 100,56(7)°. [SbCl2(18-Krone-6)]+SbCl6- enthält Kationen, in denen das Antimonatom in erster Koordinationssphäre φ-trigonal-bipyramidal von zwei O-Atomen des Kronenethers in Axialposition und von den beiden Cl-Atomen sowie dem freien Elektronenpaar äquatorial umgeben ist.
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  • 7
    ISSN: 0044-2313
    Keywords: Rhenium Complexes ; Syntheses ; IR spectra ; Crystal Structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Crystal Structures of (NH4)2[ReCl6], [ReCl2(CH3CN)4]2[ReCl6] · 2CH3CN and [ReCl4(18)(Crown-6)]Brown single crystals of (NH4)2[ReCl6] are formed by the reaction of NH4Cl with ReCl5 in a suspension of diethylether. [ReCl2(CH3CN)4]2[ReCl6] · 2CH3CN crystallizes as brown crystal plates from a solution of ReCl5 in acetonitrile. Lustrous green single crystals of [ReCl4(18-crown-6)] are obtained by the reaction of 18-crown-6 with ReCl5 in a dichloromethane suspension. All rhenium compounds are characterized by IR spectroscopy and by crystal structure determinations.(NH4)2[ReCl6]: Space group Fm3m, Z = 4, 75 observed unique reflections, R = 0.01. Lattice constant at -70°C: a = 989.0(1) pm. The compound crystallizes in the (NH4)2[PtCl6] type, the Re—Cl distance is 235.5(1) pm.[ReCl2(CH3CN)4]2[ReCl6] · 2CH3CN: Space group P1, Z = 1, 2459 observed unique reflections, R = 0.12. Lattice dimensions at -60°C: a = 859.0(1), b = 974.2(7), c = 1287.3(7) pm, α = 102.69(5)°, b̃ = 105.24(7)°, γ = 102.25(8)°. The structure consists of two symmetry-independent [ReCl2(CH3CN)4]+ ions with trans chlorine atoms, [ReCl6]2- ions, and included acetonitrile molecules. In the cations the Re—Cl bond lengths are 233 pm in average, in the anion they are 235 pm in average.[ReCl4(18-crown-6)]: Space group P21/n, Z = 4, 3 633 observed unique reflections, R = 0.06. Lattice dimensions at -70°C: a = 1040.2(4), b = 1794.7(5), c = 1090.0(5) pm, b̃ = 108.91(4)°. The compound forms a molecular structure, in which the rhenium atom is octahedrally coordinated by the four chlorine atoms and by two oxygen atoms of the crown ether molecule.
    Notes: Braune Einkristalle von (NH4)2[ReCl6] entstehen durch Reaktion von NH4Cl mit ReCl5 in einer Diethylethersuspension. [ReCl2(CH3CN)4]2[ReCl6] · 2CH3CN kristallisiert als braune Kristallplättchen aus einer Lösung von ReCl5 in Acetonitril. Leuchtend grüne Einkristalle von [ReCl4(18-Krone-6)] entstehen durch Reaktion von 18-Krone-6 mit ReCl5 in einer Dichlormethansuspension. Die drei Rhenium-Verbindungen werden durch ihre IR-Spektren und durch Kristallstrukturanalysen charakterisiert.(NH4)2[ReCl6]: Raumgruppe Fm3m, Z = 4, 75 unabhängige beobachtete Reflexe, R = 0,01. Gitterkonstante bei -70°C: a = 989,0(1) pm. Die Verbindung kristallisiert im (NH4)2[PtCl6]-Typ, der Re—Cl-Abstand beträgt 235,5(1) pm.[ReCl2(CH3CN)4]2[ReCl6] · 2CH3CN: Raumgruppe P1, Z = 1, 2459 beobachtete unabhängige Reflexe, R = 0,12. Gitterkonstanten bei -60°C: a = 859,0(1); b = 974,2(7); c = 1287,3(7) pm, α = 102,69(5)°; b̃ = 105,24(7)°; γ = 102,25(8)°. Die Struktur besteht aus zwei symmetrieunabhängigen [ReCl2(CH3CN)4]+-Ionen mit trans-ständigen Chloratomen, [ReCl6]2--Ionen und eingelagerten Acetonitrilmolekülen. In den Kationen betragen die Re—Cl-Abstände im Mittel 233 pm, im Anion im Mittel 235 pm.[ReCl4(18-Krone-6)]: Raumgruppe P21/n, Z = 4, 3 633 beobachtete unabhängige Reflexe, R = 0,06. Gitterkonstanten bei -70°C: a = 1040,2(4); b = 1794,7(5); c = 1090,0(5) pm; b̃ = 108,91(4)°. Die Verbindung bildet eine Molekülstruktur, in der das Rheniumatom oktaedrisch von den vier Chloratomen und von zwei Sauerstoffatomen des Kronenethers koordiniert ist.
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  • 8
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 9
    ISSN: 0044-2313
    Keywords: Polyselenides ; Synthesis ; Crystal Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal Structures of the Polyselenides [Cs(18-Crown-6)]2Se5 · DMF, [Rb(222-Crypt)]2Se6, [Ba(15-Crown-5)2]Se6 · DMF, and [Na(12-Crown-4)2]Se7.The title compounds have been prepared by reactions of the corresponding diselenides with excess selenium in the presence of crown ethers in dimethylformamide solutions, forming black crystals.[Cs(18-Crown-6)]2Se5 · DMF: Space group P21/m, Z = 2, 2 194 observed unique reflections, R = 0.119. Lattice dimensions at 20°C: a = 1 041.2; b = 1 496.3; c = 1 459.7 pm; β = 100.39°. The compound forms an ionic triple with Cs…Se-contacts between 374 and 381 pm.[Rb(222-Crypt)]2Se6: Space group P1, Z = 2, 7 405 observed unique reflections, R = 0.056. Lattice dimensions at - 70°C: a = 1 106.8; b = 1 460.8; c = 1 718.8 pm; α = 89.22°; β = 86.65°; γ = 71.53°. The compound contains Se62- chains without direct contact with each other.[Ba(15-Crown-5)2]Se6 · DMF: Space group P21/n, Z = 4, 2 680 observed unique reflections, R = 0.055. Lattice dimensions at - 80°C: a = 1 051.9; b = 1 322.4; c = 2 729.9 pm; β = 100.93°. The compound contains Se62- chains, which are isolated from each other by the cations and the included DMF molecules.[Na(12-Crown-4)2]2Se7: Space group P1, Z = 2, 7 313 observed unique reflections, R = 0.042. Lattice dimensions at - 70°C: a = 1 260.9; b = 1 433.6; c = 1 462.9 pm; α = 80.27°; β = 78.60°; γ = 69.34°. The compound contains Se72- chains without direct contacts with each other.
    Notes: Die Titelverbindungen entstehen aus den entsprechenden Diseleniden mit überschüssigem Selen in Gegenwart von Kronenethern in Dimethylformamid-Lösungen in Form schwarzer Kristalle.[Cs(18-Krone-6)]2Se5 · DMF: Raumgruppe P21/m, Z = 2, 2 194 beobachtete unabhängige Reflexe, R = 0,119. Gitterabmessungen bei 20°C: a = 1 041,2; b = 1 496,3; c = 1 459,7 pm; β = 100,39°. Die Verbindung bildet ein Ionentripel mit Cs…Se-Kontakten zu dem kettenförmigen Se52--Ion von 374 bis 381 pm.[Rb(222-Crypt)]2Se6: Raumgruppe P1, Z = 2, 7 405 beobachtete unabhängige Reflexe, R = 0,056. Gitterabmessungen bei - 70°C: a = 1 106,8; b = 1 460,8; c = 1 718,8 pm; α = 89,22°; β = 86,65°; γ = 71,53°. Die Verbindung enthält kettenförmige Se62--Ionen, die keine Kontakte untereinander ausbilden.[Ba(15-Krone-5)2]Se6 … DMF: Raumgruppe P21/n, Z = 4, 2 680 beobachtete unabhängige Reflexe, R = 0,055. Gitterabmessungen bei - 80°C: a = 1 051,9; b = 1 322,4; c = 2 729,9 pm; β = 100,93°. Die Verbindung enthält kettenförmige Se62--Ionen, die im Gitter durch die Kationen und die eingelagerten DMF-Moleküle voneinander isoliert sind.[Na(12-Krone-4)2]2Se7: Raumgruppe P1, Z = 2, 7 313 beobachtete unabhängige Reflexe, R = 0,042. Gitterabmessungen bei - 70°C: a = 1 260,9; b = 1 433,6; c = 1 462,9 pm; α = 80,27°; β = 78,60°; γ = 69,34°. Die Verbindung enthält kettenförmige Se72--Ionen, die keine direkten Kontakte untereinander ausbilden.
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  • 10
    ISSN: 0044-2313
    Keywords: Phosphaneimine Complexes of Zinc and Cobalt ; Synthesis ; IR spectra ; Crystal Structures ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses and Crystal Structures of the Phosphaneimine Complexes MCl2(Me3SiNPMe3)2 with M = Zn and Co, and CoCl2(HNPMe3)2The molecular complexes MCl2(Me3SiNPMe3)2 (M = Zn, Co) have been prepared by the reaction of the dichlorides of zinc and cobalt with Me3SiNPMe3 in CH3CN and CH2Cl2, respectively, whereas the complex CoCl2(HNPMe3)2 has been prepared by the reaction of CoCl2 with NaF in boiling acetonitrile in the presence of Me3SiNPMe3. All complexes were characterized by IR spectroscopy and by crystal structure determinations. The complexes MCl2(Me3SiNPMe3)2 crystallize isotypically.ZnCl2(Me3SiNPMe3)2: Space group P212121, Z = 4, 2677 observed unique reflections, R = 0.024. Lattice dimensions at -70°C: a = 1243.6; b = 1319.0; c = 1464.7 pm.CoCl2(Me3SiNPMe3)2: Space group P212121, Z = 4, 3963 observed unique reflections, R = 0,071. Lattice dimensions at -80°C: a = 1236.3; b = 1317.4; c = 1457.6 pm.CoCl2(HNPMe3)2 · CH2Cl2: Space group Pbca, Z = 8, 1354 observed unique reflections, R = 0.055. Lattice dimensions at -80°C: a = 1247.3; b = 998.4; c = 2882.4 pm.All complexes have monomeric molecular structures, in which the metal atoms are coordinated in a distorted tetrahedral fashion by the two chlorine atoms and by the nitrogen atoms of the phosphaneimine molecules.
    Notes: Die Molekülkomplexe MCl2(Me3SiNPMe3)2 (M = Zn, Co) entstehen aus den wasserfreien Dichloriden von Zink und Cobalt mit Trimethylsilyl-trimethylphosphanimin in Dichlormethan bzw. Acetonitril, während der Trimethylphosphanimin-Komplex CoCl2(HNPMe3)2 aus CoCl2 mit Natriumfluorid in Gegenwart von Me3SiNPMe3 in siedendem Acetonitril gebildet wird. Die Verbindungen werden durch ihre IR-Spektren und durch Kristallstrukturanalysen charakterisiert. Die Komplexe MCl2(Me3SiNPMe3)2 (M = Zn, Co) sind miteinander isotyp.ZnCl2(Me3SiNPMe3)2: Raumgruppe P212121, Z = 4, Strukturlösung mit 2677 beobachteten unabhängigen Reflexen, R = 0,024. Gitterkonstanten bei -70°C: a = 1243,6; b = 1319,0; c = 1464,7 pm.CoCl2(Me3SiNPMe3)2: Raumgruppe P212121, Z = 4, Strukturlösung mit 3963 beobachteten unabhängigen Reflexen, R = 0,071. Gitterkonstanten bei -80°C: a = 1236,3; b = 1317,4; c = 1457,6 pm.CoCl2(HNPMe3)2 · CH2Cl2: Raumgruppe Pbca, Z = 8, Strukturlösung mit 1354 beobachteten unabhängigen Reflexen, R = 0,055. Gitterkonstanten bei -80°C: a = 1247,3; b = 998,4; c = 2882,4 pm.Alle Komplexe haben monomere Molekülstrukturen, in denen die Metallatome verzerrt tetraedrisch von den beiden Chloratomen und den N-Atomen der beiden Phosphaniminmoleküle koordiniert sind.
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