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  • 1
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 74 (1970), S. 315-325 
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Von 18 Stämmen von Bifidobacterium longum Reuter und einem Stamm von B. lactentis Reuter wurden die Zellwände in üblicher Weise hergestellt. Sie enthielten Mur, GlcNH2, d-Glu, Ala, l-Orn (l-Lys), Thr, Ser in einem Molverhältnis von rund 1:1:1:4:1:1:1. Die Molverhältnisse änderten sich nicht, wenn die Zellwände mit Trichloressigsäure oder heißem Formamid extrahiert wurden. In einigen Stämmen trat mehr als 1 Mol Glutaminsäure pro Mol Diaminosäure auf. Die zusätzliche Glutaminsäure hatte die l-Konfiguration. Sie war kein Bestandteil des Mureins, sondern einer lysozymunempfindlichen, unbekannten Zellwandkomponente, vermutlich einer Polyglutaminsäure. l-Ornithin war in den meisten Stämmen die dominierende Diaminosäure, während l-Lysin nur mit einem Anteil von 10–20% vertreten war. In 2 Stämmen war l-Lysin dominierend (90%). Die Aminosäuresequenz wurde durch die Analyse der Oligopeptide aus Partialhydrolysaten bestimmt. Die an Mureinsäure gebundenen Peptiduntereinheiten hatten die auch von anderen Mureinen bekannte Sequenz: l-Ala-d-Glu-l-Orn (oder l-Lys)-d-Ala. Glutaminsäure ist wahrscheinlich amidiert, wie aus dem Auftreten von rund 1 Mol NH3 im Hydrolysat der Zellwände zu schließen ist. Die Interpeptidbrücke besteht aus dem Peptid l-Ala-Thr-l-Ala-l-Ser. Sie ist mit dem C-terminalen Serin an die ω-Aminogruppe der Diaminosäure der Peptiduntereinheit gebunden. Die Quervernetzung erfolgt zwischen dem N-terminalen Alanin der Interpeptidbrücke zum C-terminalen d-Alanin einer Peptiduntereinheit. Da 4% des gesamten Alanins und 3% der δ-Aminogruppe des Ornithins dinitrophenylierbar sind, ist anzunehmen, daß die Quervernetzung nur zu etwa 80% verwirklicht ist.
    Notes: Summary Cell walls of 18 strains of Bifidobacterium longum Reuter and one strain of B. lactentis Reuter were prepared in the usual way. They contained Mur, GlcNH2, d-Glu, Ala, l-Orn (l-Lys), Thr, Ser in a molar ratio of about 1:1:1:4:1:1:1. The ratio was not changed when the cell walls were extracted by trichloroacetic acid or hot formamide. In some strains more than 1 mole glutamic acid per mole of diamino acid was present. The additional glutamic acid was of the l-rather than the d-form. It was not a constituent of the murein, but of an unknown lysozyme insensitive cell wall component, probably a polyglutamic acid. l-Ornithine was the dominating diamino acid in most strains but l-lysine was also present in a portion of 10 to 20%. In 2 strains l-lysine was dominating (90%). The amino acid sequence was determined by analysing the oligopeptides arising during partial acid hydrolysis. It was shown that the peptide subunits attached to the muramic acid are the same as those of other mureins: l-Ala-d-Glu-l-Orn (or l-Lys)-d-Ala. glutamic acid is probably amidated, since about 1 mole of NH3 is released by acid hydrolysis of the cell walls. The interpeptide bridge consists of the peptide l-Ala-Thr-l-Ala-l-Ser which is bound by its C-terminal serine to the ω-amino group of the diamino acid of one peptide subunit and by its N-terminal l-alanine to the C-terminal d-alanine of another peptide subunit. About 4% of the total alanine and 3% of the δ-amino groups of ornithine of the cell wall can be dinitrophenylated. This indicates that about 20% of the peptide subunits are not crosslinked.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 1264-1271 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Phosphorus, 88. 1,2,3-Triphenyl-1,3-bis(trimethylsilyl)triphosphaneThe reaction of 1,3-dipotassium 1,2,3-triphenyltriphosphide, K2 (PPh)3, with chlorotrimethyl-silane yields the hitherto unknown title compound Me3Si(Ph)P—P(Ph)—P(Ph)SiMe3 (1), which is remarkably stable against disproportionation reactions. In solution it forms the three diastereomers 1a (erythro/erythro), 1b (erythro/threo), and 1c (threo/threo) in a ratio of about 8:3:1, between which a dynamic equilibrium exists due to pyramidal inversion at the P-atoms. The correlation between the 31P-NMR-spectroscopically observed spin systems and the diastereomers 1a-c results from the significant dependence of the 1JPP-coupling constants on dihedral angles. The preferred trans arrangement of the bulky SiMe3- and P(Ph)SiMe3 groups at adjacent P-atoms leads to a trans-conformation of the lone electron pairs in the erythro- and to a gauche-conformation in the threo-configuration.
    Notes: Die Reaktion von 1,3-Dikalium-1,2,3-triphenyltriphosphid, K2(PPh)3, mit Chlortrimethylsilan ergibt in guter Ausbeute die bislang unbekannte Titelverbindung Me3Si(Ph)P—P(Ph)—P(Ph)SiMe3 (1), die gegenüber Disproportionierungsreaktionen bemerkenswert beständig ist. Sie bildet in Lösung die drei Diastereomeren 1a (erythro/erythro), 1b (erythro/threo) und 1c (threo/threo) im Verhältnis von etwa 8:3:1, die infolge pyramidaler Inversion der P-Atome in einem dynamischen Gleichgewicht miteinander stehen. Die Korrelation zwischen den 31P-NMR-spektroskopisch beobachteten Spinsystemen und den Diastereomeren 1a-c ergibt sich aufgrund der signifikanten Torsionswinkelabhängigkeit der 1JPP-Kopplungskonstanten. Die bevorzugte trans-Anordnung der großvolumigen SiMe3- und P(Ph)SiMe3-Reste an benachbarten P-Atomen führt bei erythro-Konfiguration zu einer trans- und bei threo-Konfiguration zu einer gauche-Konformation der freien Elektronenpaare.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 1217-1220 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Contributions to the Chemistry of Phosphorus, 78: 1,2,3-TriphenyltriphosphaneAmong the disproportionation products of 1,2-diphenyldiphosphane (1), 1,2,3-triphenyltriphosphane (2) could be enriched up to the maximum concentration of ≍50% with respect to the total phosphorus. 2 was identified by the 31P{1H} NMR spectrum that exhibits, in the region of openchain triphosphanes, two A2B and one ABC spin system for the three diastereomers, of which the NMR parameters are reported. Contrary to results given in the literature, 2 is not stable at room temperature, but disproportionates to give lower and higher homologues of the series H(PPh)nH as well as cyclic phenylphosphanes, especially (PPh)5.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 1210-1216 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Phosphorus, 73: 1,2-Diphenyldiphosphane1,2-Diphenyldiphosphane (1) is formed, contrary to results given in the literature, by the reaction of KHPPh with 1,2-dibromoethane. Pure 1 is obtained by hydrolysis or alcoholysis of Me3Si(Ph)P-P(Ph)SiMe3 in the dark. It is stable at - 30°C. 1 disproportionates at room temperature to give PhPH2, higher homologues of the series H2[PPh]n, especially H2[PPh]3, and cyclic phenylphosphanes [PPh]n, mainly [PPh]5. These rearrangements are accelerated by light, phosphides, and strong acids and bases. With K(Ph)P—P(Ph)K, Me3Si(Ph)P—P(Ph)SiMe3, and P2Ph4 1 reacts to give the asymmetric diphosphanes K(Ph)P—P(Ph)H, Me3Si(Ph)P—P(Ph)H, and Ph2P—P(Ph)H, respectively. The NMR, IR, and Raman spectra are discussed.
    Notes: 1,2-Diphenyldiphosphan (1) wird - entgegen Literaturangaben - bei der Reaktion von KHPPh mit 1,2-Dibromethan gebildet. Reines 1 ist durch Hydrolyse oder Alkoholyse von Me3Si(Ph)P - P(Ph)SiMe3 unter Lichtausschluß erhältlich und bei - 30°C beständig. Es disproportioniert bei Raumtemperatur in PhPH2, höhere Homologe der Reihe H2[PPh]n  -  insbesondere H2[PPh]3 - und cyclische Phenylphosphane [PPh]n  -  vor allem [PPh]5. Diese Umlagerungen werden durch Licht, Phosphide sowie starke Säuren und Basen beschleunigt. Mit K(Ph)P—P(Ph)K, Me3Si(Ph)P—P(Ph)SiMe3 oder P2Ph4 reagiert 1 zu den unsymmetrischen Diphosphanen K(Ph)P—P(Ph)H, Me3Si(Ph)P—P(Ph)H bzw. Ph2P—P(Ph)H. Die NMR-, IR- und Raman-Spektren von 1 werden diskutiert.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 3838-3842 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Contributions to the Chemistry of Phosphorus, 81: 1,2,5,6-Tetraphosphabicyclo[3.3.0]octane1,2-Bis(phosphino)ethane, H2PCH2CH2PH2 (1), reacts with phosphorus halogen compounds such as X(R)P—P(R)X, RPX2, PX3 or bromine to the hitherto unknown bicyclic di-secondary phosphane 1,2,5,6-tetraphosphabicyclo[3.3.0]octane (2). The structure of 2 was elucidated spectroscopically and by chemical ring degradation.
    Notes: 1,2-Bis(phosphino)ethan, H2PCH2CH2PH2 (1), reagiert mit Phosphorhalogenverbindungen, wie X(R)P—P(R)X, RPX2, PX3, oder Brom zu dem bislang unbekannten bicyclischen di-sekundären Phosphan 1,2,5,6-Tetraphosphabicyclo[3.3.0]octan (2). Die Konstitution von 2 wurde spektroskopisch und durch chemischen Ringabbau aufgeklärt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 15 (1976), S. 160-161 
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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