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Digitale Medien

A novel 16,24-dehydrobiladiene-ab system: The reaction of xanthobilirubic acid methyl ester with bromine (1995)

Ma, J. -S. ; Chen, Q. -Q. ; Wang, C. -Q. ; [weitere]

Springer

Monatshefte für Chemie 126 (1995), S. 201-209

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ISSN: 1434-4475

Schlagwort(e): 16,24-Dehydrobiladiene-ab ; Biladiene-ab ; Xanthobilirubic acid methyl ester ; Mesobilirubin-XIIIα ; Mesobiliverdin-XIIIα ; 14-Formyl-tripyrrinone ; 15,16-Dimethoxy-biladienes-ab

Quelle: Springer Online Journal Archives 1860-2000

Thema: Chemie und Pharmazie

Beschreibung / Inhaltsverzeichnis: Zusammenfassung Der Umsatz von Xanthobilirubinsäuremethylester mit Brom in Methanol ergibt in 20-prozentiger Ausbeute ein rotes Pigment, für das die bislang nicht bekannte 16,24-Dehydrobiladien-ab-Konstitution abgeleitet wurde. Darüber hinaus konnte das entsprechende Mesobiliverdin-XIIIα, Mesobilirubin-XIIIα, 14-Formyltripyrrinon, und zwei diastereomere 15,16-Dimethoxybiladiene-ab aus der Reaktionsmischung isoliert werden. Die mechanistischen Aspekte dieser Reaktion werden diskutiert.

Notizen: Summary On treating xanthobilirubic acid methyl ester with bromine in methanol, a red bile pigment, which was assigned the hitherto unknown 16,24-dehydrobiladiene-ab constitution, is obtained in 20% yield. In addition, the corresponding mesobiliverdin-XIIIα, mesobilirubin-XIIIα, 14-formyl-tripyrrinone, and two diastereomeric 15,16-dimethoxybiladienes-ab could be isolated from the reaction mixture. The mechanistic aspects of this reaction are discussed.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00812248

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Digitale Medien

1,2-bis-Dipyrrinon-9-yl-ethene — a novelb-homo-verdian chromophore: the reaction of 9-methyl-10H-dipyrrin-1-ones with bromine (1995)

Chen, Q. -Q. ; Ma, J. -S. ; Wang, C. -Q. ; [weitere]

Springer

Monatshefte für Chemie 126 (1995), S. 983-991

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ISSN: 1434-4475

Schlagwort(e): 1,2-bis-Dipyrrinon-9-yl-ethene ; b-homo-Verdin ; Mesobiliverdin-XIIIα

Quelle: Springer Online Journal Archives 1860-2000

Thema: Chemie und Pharmazie

Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Reaktion von 9-Methyl-10H-dipyrrin-1-onen mit Brom in Dichlormethan ergab in mäßigen Ausbeuten rotgefärbte Gallenfarbstoffderivate. Sie konnten strukturell als 1,2-bis-Dipyrrinon-ethene zugeordnet werden, die ein Beispiel für die bisher unbekanntenb-Homoverdine darstellen. Darüber hinaus konnten aus der Reaktionsmischung die entsprechenden Mesobiliverdine-XIIIα isoliert werden. Die mechanistischen Aspekte dieser Reaktion werden diskutiert.

Notizen: Summary Upon treatment of 9-methyl-10H-dipyrrin-1-ones with bromine in dichloromethane, red bile pigment derivatives were obtained in moderate yields. They were structurally assigned as 1,2-bis-dipyrrinon-9-yl-ethenes, which are examples of the hitherto unknownb-homo-verdins. In addition, the correspondingmeso-biliverdins-XIIIα could be isolated from the reaction mixture. The mechanistic aspects of the reaction are discussed.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00811018

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Digitale Medien

Preliminary X-ray crystallographic analysis of Tritrichomonas foetus inosine-5′-monophosphate dehydrogenase (1995)

Whitby, Frank G. ; Huete-Perez, Jorge ; Luecke, Hartmut ; [weitere]

New York, NY : Wiley-Blackwell

Proteins: Structure, Function, and Genetics 23 (1995), S. 598-603

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ISSN: 0887-3585

Schlagwort(e): inosine monophosphate dehydrogenase ; Tritrichomonas foetus ; crystallization ; X-ray diffraction ; purine ; Chemistry ; Biochemistry and Biotechnology

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Medizin

Notizen: Inosine-5′-monophosphate dehydrogenase (IMPDH) from the protozoan parasite Tritrichomonas foetus has been expressed in E. coli and crystallized. Crystals were grown to 0.1 mm in each dimension in 18 to 72 h using ammonium sulfate and low-molecular-weight polyethylene glycols. The crystals belong to the cubic space group P432 with unit cell edge = 157.25 Å. The enzyme is a homotetramer with each monomer having a molecular weight of 55,534 Da. There is one monomer per asymmetric unit, based on a volume/mass ratio of 2.7 Å3/Da and self-rotation analysis. The crystals are adequately stable to allow a complete data set to be collected from a single crystal. Complete native data sets have been collected to 2.3 Å resolution at 4°C using synchrotron radiation. High-quality complete data extending to 3.0 Å resolution have been collected from crystals of four putative derivatives, and the data appear to be isomorphous with that of the native crystals in each case. Efforts to solve the derivatives for use in MIR phasing are underway. © 1995 Wiley-Liss, Inc.

Zusätzliches Material: 3 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/prot.340230417

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Digitale Medien

Holographic grating relaxation studies of probe diffusion in amorphous polymers (1995)

Xia, Jiulin ; Wang, C. H.

Bognor Regis [u.a.] : Wiley-Blackwell

Journal of Polymer Science Part B: Polymer Physics 33 (1995), S. 899-908

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ISSN: 0887-6266

Schlagwort(e): probe diffusion ; holographic grating relaxation ; temperature dependence ; Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Physik

Notizen: Probe diffusion of camphorquinone, thymoquinone, and diacetyl in polymers was studied by the laser-induced holographic grating relaxation (HGR) technique in polymers. The effects of changing the probe size and various parameters of the polymer, such as the molecular weight, chain conformation, and the glass transition temperature, on the probe diffusion coefficient have been investigated. Furthermore, effects of cross-linking and plasticizing the chains of the polymer host on the probe diffusion coefficient were also studied. Temperature-dependent studies show that except for the very low molecular weight poly(methyl methacrylate), all probe diffusion coefficient data above the glass transition temperature fit well to the WLF equation. ©1995 John Wiley & Sons, Inc.

Zusätzliches Material: 10 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/polb.1995.090330605

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Digitale Medien

Studies on the formation of novel copolyesters containing naphthalene and aralkyloxy structures (1995)

Sun, Y.-M. ; Wang, C.-S.

New York, NY [u.a.] : Wiley-Blackwell

Journal of Applied Polymer Science 58 (1995), S. 1189-1197

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ISSN: 0021-8995

Schlagwort(e): Chemistry ; Polymer and Materials Science

Quelle: Wiley InterScience Backfile Collection 1832-2000

Thema: Chemie und Pharmazie , Maschinenbau , Physik

Notizen: Copolyesters containing naphthalene structure were synthesized from bis(hydroxyethyl)naphthalate (BHEN) and various aralkyloxy diols. The starting bis(4-(2-hydroxyethoxy)aryl) compounds were derived from a nucleophilic substitution of various bisphenols with ethylene carbonate in the presence of potassium iodide (KI). Copolyesters having intrinsic viscosities of 0.50 to 0.60 dL/g were obtained by melt polycondensation in the presence of metallic catalysts. The effects of reaction temperature and time on the formation of copolyesters were investigated in order to obtain an optimum condition for copolyester manufacturing. The optimal reaction temperature and time were found to be 290 to 310°C and 90 to 120 min, respectively. Most of these copolyesters have better solubilities than polyethylene naphthalate (PEN) in aprotic solvents such as N-methyl-2-pyrrolidone or m-cresol. The thermal properties of the copolyesters were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Glass transition temperatures of these copolyesters were in the range of 90 to 141°C, and 10% weight loss values in nitrogen were all above 460°C. © 1995 John Wiley & Sons, Inc.

Zusätzliches Material: 6 Ill.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1002/app.1995.070580712

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