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  • 1
    Electronic Resource
    Electronic Resource
    Transformation von Uridin- zu Cytidinderivaten durch selektive Aminierung (1989)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 331 (1989), S. 835-842 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transformation of Uridine Derivatives into Cytidines via Selective AminationThe synthesis of some 5-fluorosubstituted cytidine 2 derivatives via amination of corresponding uridine derivatives 1 is described. 5-Substituted 4-tetrazolo pyrimidinone derivatives 5 are key intermediates in the procedure. The method used is extended to other fluorinated starting materials, e.g. fluorinated uridinedinueleotides 7 or 2′-deoxy-2′-fluorouridine 9. The fluoro containing products are easily available by fluorination with elemental fluorine or hydrogene fluoride.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19893310518
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  • 2
    Electronic Resource
    Electronic Resource
    Molekülstruktur von 2,2-Bis(diisopropoxyphosphonyl)propyl-methylzinndibromid (1993)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 619 (1993), S. 859-864 
    Details
    ISSN: 0044-2313
    Keywords: 2,2-Bis(diisopropoxyphosphonyl)propyl methyltin dibromide ; synthesis ; crystal structure ; n.m.r. data ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Molecular Structure of 2,2-Bis(diisopropoxyphosphonyl)propyl Methyltin DibromideBy methylation of Me3SnCH2CH[P(O)(OPr-i)2]2 with NaH/MeI Me3SnCH2C(Me)[P(O)(OPr-i)2]2 (1) is obtained, which is converted by bromine into the dibromide MeBr2SnCH2C(Me)[P(O)(OPr-i)2]2 (2). An X-ray crystal structure analysis shows 2 to be monomeric. The tin atom is situated in the centre of a distorted octahedron, in which the functional substituent is intramolecular coordinated as tridentate ligand in a facial mode. The two organo groups are arranged in trans-position (C—Sn—C 155.1°), whereas the oxygen and bromine atoms are orientated cis to each other. The six-membered ring of the bicyclic molecular fragment of 2 which results from the coordination of the functional organo group to the tin atom shows a boat-conformation, whereas the two five-membered rings exist in twist-conformations. Multinuclear n.m.r. and i.r. data show that 2 retains its solid state structure also in nonpolar solvents.
    Notes: Durch Methylierung von Me3SnCH2CH[P(O)(OPr-i)2]2 mittels NaH/MeI erhält man Me3SnCH2C(Me)[P(O)(OPr-i)2]2 (1), das mit Brom in das Dibromid MeBr2SnCH2C(Me)[P(O)(OPr-i)2]2 (2) überführt wird. Nach der Röntgenkristallstrukturanalyse ist 2 im Festkörper monomer. Das Zinnatom befindet sich im Zentrum eines verzerrten Oktaeders, in dem der funktionelle Substituent intramolekular als tridentater Ligand in facialer Anordnung koordiniert ist. Die beiden Organoreste sind trans-ständig angeordnet (C—Sn—C 155,1°), während sich die Sauerstoff- und Bromatome in cis-Anordnung zueinander befinden. Der Sechsring des aus der Koordination des funktionellen Organorestes am Zinnatom resultierenden bicyclischen Molekülfragmentes von 2 weist Wannenkonformation auf, während die beiden Fünfringe in Twist-Konformationen vorliegen. Multikern-NMR- und IR-Daten belegen, daß 2 seine Festkörperstruktur auch in unpolaren Lösungsmitteln beibehält.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19936190509
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  • 3
    Electronic Resource
    Electronic Resource
    C-Stannylmethylierte N-Acetyl- und N-Formyl-aminomalonsäure-DerivateProfessor Kurt Issleib in memoriam (1995)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 621 (1995), S. 63-71 
    Details
    ISSN: 0044-2313
    Keywords: diethyl triorganostannylmethyl N-acyl aminomalonates ; ethyl 3-(trimethylstannyl)-N-acyl alaninates ; 1,2-oxastannolane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: C-Stannylmethylated N-Acetyl- and N-Formyl-aminomalonic Acid DerivativesTin compounds of the type Me3SnCH2C(NHCOR) · (COOEt)2 (1: R = CH3; 2: R = H) are synthesized by reaction of acylaminomalonates with iodomethyl trimethylstannane. The halogenation of 1 and 2 yields the halostannylsubstituted compounds Me3-nXnSnCH2C(NHCOR)(COOEt)2 3-6 (R = Me, H; n = 1, 2; X = Cl, Br). The decarbethoxylation (KRAPCHO reaction) of 1 and 2 gives ethyl 3-(trimethylstannyl)-N-acyl alaninates (7 and 8). With one equivalent KOH 1 and 2 are transformed into the monoethyl malonates of the type Me3SnCH2C(NHCOR)(COOH)(COOEt) (9: R = CH3), which convert simultaneously under decarboxylation into 7 and 8 and by cyclisation under elimination of methane into the 1,2-oxastannolane derivatives 10 and 11. IR, NMR data and the determination of the crystal structure reveal for MeBr2SnCH2C(NHCOCH3)(COOEt)2 (5) hexacoordinated tin by intramolecular coordination of the amide-CO and one of the ester-CO groups.
    Notes: Zinnverbindungen des Typs Me3SnCH2C(NHCOR)(COOEt)2 (1: R = CH3; 2: R = H) werden durch Umsetzung von Acylaminomalonsäureestern mit Iodomethyltrimethylstannan dargestellt. Die Halogenierung von 1 und 2 liefert die halogenostannylsubstituierten Verbindungen Me3-nXnSnCH2C(NHCOR)(COOEt)2 3-6 (R = Me, H; n = 1, 2; X = Cl, Br). Die Decarbethoxylierung (KRAPCHO-Reaktion) von 1 und 2 führt zu 3-(Trimethylstannyl)-N-acyl-alaninethylestern (7 und 8). Mit einem Äquivalent KOH werden 1 und 2 in die Monoethylester des Typs Me3SnCH2C(NHCOR)(COOH)(COOEt) (9: R = CH3) überführt, die sich in Folgereaktionen sowohl unter Decarboxylierung zu 7 bzw. 8 als auch durch Cyclisierung unter Methanabspaltung zu den 1,2-Oxastannolanderivaten 10 bzw. 11 umwandeln. IR-, NMR-Daten und die Bestimmung der Kristallstruktur beweisen für MeBr2SnCH2C(NHCOCH3)(COOEt)2 (5) hexakoordiniertes Zinn durch intramolekulare Koordination der Amid-CO- sowie einer Ester-CO-Gruppe.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19956210112
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  • 4
    Electronic Resource
    Electronic Resource
    Pseudoelementverbindungen. VII [1]. Kristall- und Molekülstruktur von Tris(ethylendiamin)nickel(II)-bis(2-methyl-4-chlorphenoxycyanamidoacetat)Professor Heinrich Kriegsmann zum 70. Geburtstag gewidmet (1996)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 622 (1996), S. 361-366 
    Details
    ISSN: 0044-2313
    Keywords: Cyanamidocarboxylate complexes ; IR ; crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Pseudoelement Compounds VII. [1] Crystal and Molecular Structure of Tris(ethylenediamine)nickel(II)-bis(2-methyl-4-chlorophenoxy-cyanamidoacetate)Surprisingly, in the presence of ethylenediamine 2-methyl-4-chlorphenoxy-cyanamidoactetate reacts with nickel(II) and copper(II) ions preferentially under formation of complexes of the type [M(en)3]X2. The IR spectra and the X-ray diffraction investigations corresponding to [Ni(en)3][2-Me-ClC6H3OCH2C(O)NCN]2 show that two cyanamidocarboxylate ions [RC(O)NCN]- are bonded to the complex cation through, in each case, two N—H … O=C hydrogen bonds between NH protons of ethylenediamine ligands and the carbonyl oxygen atoms. Additionally, in the crystal weak N—H … N≡C bridges were found between the nitrile nitrogen atoms of the anions and NH protons of neighbouring complex cations.
    Notes: 2-Methyl-4-chlorphenoxy-cyanamidoacetat bildet zu unserer Überraschung mit Nickel(II)- und Kupfer(II)-Ionen in Gegenwart von Ethylendiamin bevorzugt Komplexe der Zusammensetzung [M(en)3]X2. IR-spektroskopische Messungen und die Kristallstruktrukturuntersuchung an [Ni(en)3][2-Me-4-ClC6H3OCH2C(O)NCN]2 zeigen, daß zwei Cyanamidocarboxylat-Anionen [RC(O)NCN]- über jeweils zwei N—H … O=C-Wasserstoffbrückenbindungen zwischen N—H-Protonen der Ethylendiamin-Liganden und den Carbonyl-Sauerstoffatomen an ein komplexes Kation [Ni(en)3]2+ gebunden sind. Im Kristall liegen außerdem noch schwache N—H … N≡C-Brücken zwischen Nitril-N-Atomen der Anionen und NH-Protonen benachbarter komplexer Kationen vor.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19966220226
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