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  • Artikel  (15)
  • Polymer and Materials Science  (8)
  • Organic Chemistry  (7)
  • Wiley-Blackwell  (15)
  • American Physical Society
  • Springer Nature
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  • Artikel  (15)
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  • Wiley-Blackwell  (15)
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  • 1
    Digitale Medien
    Digitale Medien
    A convenient synthesis of functional monomers: Unsaturated spiroorthoesters using phase transfer catalysis (1988)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 189 (1988), S. 287-292 
    Details
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Unsaturated spiroorthoesters, which undergo no shrinkage on polymerization, were synthesized in high yield by an elimination reaction of the corresponding halomethylated spiroorthoesters with potassium hydroxide (KOH) or potassium tert-butoxide (t-BuOK) using a phase transfer catalyst. It was found that tetrabutylammonium bromide exhibits a catalytic activity higher than that of the other quaternary ammonium salts, 18-crown-6 and poly(ethylene glycol) (M̄w = 300) under equal conditions. The elimination reaction of halomethylated spiroorthoesters proceeds easily in toluene or diglyme with t-BuOK and in tert-butyl alcohol with KOH leading to the corresponding unsaturated compounds in high yields. In addition, the bromomethylated spiroorthoesters showed higher reactivity than the chloromethylated spiroorthoesters under equal conditions.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/macp.1988.021890204
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  • 2
    Digitale Medien
    Digitale Medien
    Polymerization of silicon-containing acetylenes. 5. Polymerization of 1-silyl-1-propynes by TaCl5-based catalystsSee Ref. 1 for part 4. (1987)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 25 (1987), S. 1353-1362 
    Details
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Polymerization of homologues of 1-(trimethylsilyl)-1-propyne [CH3C≡CSi(CH3)3] was studied. CH3C≡CSi(CH3)2(n-C6H13) (I) polymerized with 1 : 1 mixtures of TaCl5 and organometallic cocatalysts (e.g., Ph4Sn and Ph3Bi) to produce in good yields a polymer having a weight-average molecular weight (Mw) over 1 × 106. CH3C≡CSi(CH3)2 Ph (II) and CH3C≡CSi(C2H5)3 (III) formed polymers having Mw's of ∼ 5 × 105 in moderate yields in the presence of TaCl5-based catalysts. In contrast, none of CH3C≡CSi(CH3)2(i-C3H7), CH3C—CSi(CH3)2(t,-C4H9), C2H5C≡CSi(CH3)3, and n,-C4H9C≡CSi(CH3)3 polymerized, which is attributed to the steric effect of the monomers. Some other 1-silyl-1-propynes also failed to polymerize. The three new polymers formed from (I)-(III) had the structure \documentclass{article}\pagestyle{empty}\begin{document}$\rlap{--} [{\rm CCH}_{\rm 3} \hbox{=\hskip-2pt=} {\rm C(SiRR'R''}\rlap{--} ]_n$\end{document} according to IR and 13C-NMR spectra. They were white solids, soluble in low-polarity solvents (e.g., toluene and chloroform) and stable enough in air at room temperature.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1987.080250513
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  • 3
    Digitale Medien
    Digitale Medien
    Synthesis and thermal self-crosslinking reaction of polymer containing spiro ortho ester and carboxylic acid (1989)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 681-690 
    Details
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Polymers with both pendant spiro ortho ester and carboxylic acid moieties were synthesized by partial esterification of poly(methacrylic acid), poly(methacrylic acid-co-methyl methacrylate), or poly(methacrylic acid-co-styrene) with halomethylated spiro ortho esters in the presence of 1,8-diazabicyclo[5,4,0]undecene-7 in dimethyl sulfoxide. The extent of esterification increased with increasing reaction temperature. The reaction of polymeric carboxylic acids with chloromethylated spiro ortho esters proceeded to 80% of conversion at 100°C for 120 h. In contrast, the degree of esterification with bromomethylated spiro ortho ester reached 80% at 60°C within 24 h. Thermo-crosslinking of polymers having pendant spiro ortho ester moiety and carboxylic acid could be effected in films. The rate of spiro ortho ester ring-opening increased with increasing reaction temperature and with increasing content of carboxylic acid groups in the polymer. Further, the rates of gel production were also measured. The polymer containing an equimolar mixture of spiro ortho ester moieties and carboxylic acids exhibited the highest reactivity. In addition, it was found that thermal crosslinking reaction of the polymer occurred with minimum volume shrinkage.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1989.080270227
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  • 4
    Digitale Medien
    Digitale Medien
    Polymerization of 1-(trimethylsilyl)-1-propyne homologs containing two silicon atoms by tantalum- and niobium-based catalystsPart 6 of “Polymerization of Heteroatom-Containing Acetylenes.” For part 5, see ref 1. (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 1839-1848 
    Details
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Polymerization of new 1-(trimethylsilyl)-1-propyne homologs containing two silicon atoms [CH3C≡CSi(CH3)2CH2Si(CH3)3 and CH3C≡CSi(CH3)2CH2CH2Si(CH3)3] was investigated by use of Ta and Nb catalysts. CH3C≡CSi(CH3)2CH2Si(CH3)3 was polymerized quantitatively by TaCl5 alone to provide a polymer having molecular weight over 106. CH3C≡CSi(CH3)2CH2CH2Si(CH3)3 was polymerized in good yield by an equimolar mixture of TaCl5 with an appropriate organometallic cocatalyst such as Ph4Sn to give a polymer with molecular weight of ca. 4 X 105. Nb catalysts were less active toward these monomers than the corresponding Ta catalysts. These two kinds of polymers had alternating double bonds along the main chain according to IR and 13C-NMR spectra. Both polymers were white solids completely soluble in low-polarity solvents like toluene, and solution casting afforded uniform, tough films. These polymers were thermally fairly stable, and their softening points were above 350°C. Films of these polymers showed smaller oxygen permeability coefficients [Po2 = 4 × 10-9 - 8 × 10-9 cm3(STP) · cm/(cm2·sec·cmHg)] but larger separation factors [(Po2/Po2) = 3.4 - 3.6] than a poly[1-(trimethylsilyl)-1-propyne] film.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/pola.1986.080240808
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  • 5
    Digitale Medien
    Digitale Medien
    Biologically Active Glycosides from Asteroidea, 37. Glycosphingolipids from the Starfish Luidia maculata, 1 Structure of A New Sulfatide Molecular Species (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1797-1800 
    Details
    ISSN: 0947-3440
    Schlagwort(e): Glycosphingolipids ; Sulfatide ; Starfish ; Luidia maculata ; Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A sulfatide molecular species [LMG-1 (1)] have been obtained from the water soluble lipid fraction of the chloroform/methanol extract of the starfish Luidia maculata. On the basis of chemical and spectroscopic findings, the structure of 1 has been elucidated. Negative FAB mass spectrometry provided important information both on the structure of the sugar moiety and on the molecular mass of the sulfatide. 1 is, to the authors' knowledge, new sulfatide molecular species and first sulfatide obtained from starfish. In addition, 1 shows neuritogenic activity toward the rat pheochromocytoma cell line, PC-12 cell.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jlac.199719970826
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  • 6
    Digitale Medien
    Digitale Medien
    Studies on the constituents of the stems of Tinospora sinensis, II. Part I. M. Yonemitsu, N. Fukuda, t. Kimura, Planta Med. 1993, 59, 552-553.. Isolation and structure elucidation of two new dinorditerpene glucosides, tinosineside A and B (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 437-439 
    Details
    ISSN: 0947-3440
    Schlagwort(e): Tinospora sinensis ; Menispermaceae ; Tinosineside A and B ; Dinorditerpene glucosides ; Terpenes ; Glucosides ; Carbohydrates ; Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Two new dinorditerpene glucosides, tinosineside A (1) and B (2-O-acetyltinosineside A, 2), were isolated from the fresh stems of Tinospora sinensis Merr. (Menispermaceae). Their structures were established on the basis of chemical and spectroscopic findings.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jlac.199519950255
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  • 7
    Digitale Medien
    Digitale Medien
    Biologically Active Glycosides from Asteroidea, 36. Re-examination of the Structure of Acanthaganglioside C, and the Identification of Three Minor Acanthagangliosides F, G and H (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 931-936 
    Details
    ISSN: 0947-3440
    Schlagwort(e): Gangliosides ; Acanthagangliosides ; Starfish ; Acanthaster planci ; N M R spectroscopy ; Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The structure of acanthaganglioside C (1) has been re-examined using MQ-COSY, TOCSY, NOESY, HSQC, HMBC and HSQC-TOCSY experiments. As a result, it is clarified that N-acetyl neuraminic acid (NeuAc) is linked to the C-3 position, and not the C-4 position, of the β-galactopyranose. In addition, three minor acanthagangliosides, F (2), G (3) and H (4), have also been isolated from the ganglioside molecular species AG-2. Their structures have been determined on the basis of chemical and spectroscopic evidence.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jlac.199719970522
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  • 8
    Digitale Medien
    Digitale Medien
    Stress relaxation of oriented nylon 6 fibers (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 24 (1979), S. 923-930 
    Details
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The stress relaxation of oriented and dried nylon 6 fibers was measured at temperatures ranging from room temperature to 423 K using a simple tensile method. After the reduction for temperature and crystallinity by Nagamatsu et al.'s procedure,2 the relaxation modulus curves were shifted along a time axis, and master curves were obtained. The Arrhenius plots of shift factor was represented by two straight lines having a break point, the temperature of which was in approximate agreement with those of the breakdown of hydrogen bonds in the amorphous region. The relationship between the breakdown of hydrogen bonds and the values of apparent activation energies for relaxation is discussed. It was found that the effects of hydrogen bonds on the relaxation behavior are similar to those of crosslinking points in crosslinked polymers. Moreover, from the constants C1 and C2 of the WLF equation, the free volume fraction at Tg(fg) and the expansion coefficient of free volume at Tg(fg) were estimated to be 0.013 and 4.2 × 10-5, respectively. Finally, through the use of the usual primary approximation method, the relaxation time spectra were obtained from the relaxation master curves. The obtained spectra showed two distributions of wedge type and box type. When the draw ratio increases, the height of distribution of the box type becomes higher and its position shifts to a longer time side, whereas those of the wedge type remain virtually unchanged.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/app.1979.070240405
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  • 9
    Digitale Medien
    Digitale Medien
    Bone morphogenetic protein encapsulated with a biodegradable and biocompatible polymer (1996)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 32 (1996), S. 433-438 
    Details
    ISSN: 0021-9304
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: To develop a controlled release system for bone morphogenetic protein (BMP), poly(DL-lactide-co-glycolide) (PLGA) capsules containing BMP were prepared by an interfacial precipitation method using a water-in-oil-in-water emulsion. The surface morphology, particle size distribution, and hydrolytic degradation rate of the PLGA capsules were examined. The encapsulation yield and release rate of BMP in vitro were measured using fluorescein isothiocyanate-labeled BMP. The amount of BMP released from PLGA capsules increased between days 3 and 5. In addition, the effectiveness of BMP encapsulated in PLGA to induce bone formation in vivo was also examined by subcutaneous implantation in rats. Complete digestion of the capsules and new bone formation including bone marrow were identified by histologic examination of harvested tissues at 3 weeks after implantation. These results demonstrated that encapsulation of BMP with PLGA could be a promising method to induce bone in clinics. © 1996 John Wiley & Sons, Inc.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Biologically active glycosides from asteroidea, XIII. Glycosphingolipids from the starfish Acanthaster planci, 2. Isolation and structure of six new cerebrosides (1988)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1988 (1988), S. 19-24 
    Details
    ISSN: 0170-2041
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Biologisch aktive Glycoside aus Asteroidea, XIII. - Glycosphingolipide aus dem Seestern Acanthaster planci, 22). - Isolierung und Struktur von sechs neuen CerebrosidenSechs neue Cerebroside (Ceramid-monohexoside), Acanthacerebrosid A (1), B (2), C (3), D (4), E (5) und F (6), wurden aus der wasserunlöslichen Lipid-Fraktion des Chloroform-Methanol-Extrakts des Seesterns Acanthaster planci isoliert. Auf Grund der chemischen und spektrometrischen Untersuchungen ließen sich die Strukturen als 1-O-(β-D-Glucopyranosyl)-substituiertes (2S,3S,4R)-2-[(2R)-2-Hydroxytetracosanoylamino]-1,3,4-hexadecanetriol (1), (2S,3S,4R)-2-[(2R)-2-Hydroxyhexadecanoylamino]-1,3,4-docosantriol (2), (2S,3S,4R,13E)-2-[(2R)-2-Hydroxyhexadecanoylamino]-13-docosen-1,3,4-triol (3), (2S,3R,4E,10E)-2-[(2R)-2-Hydroxydocosanoylamino]-4,10-octadecadien-1,3-diol (4), (2S,3R,4E,10E)-2-[(2R)-2-Hydroxytricosanoylamino]-4,10-octadecadien-1,3-diol (5) und (2S,3R,4E,10E)-2-[(2R)-2-Hydroxytetracosanoylamino]-4,10-octadecadien-1,3-diol (6) charakterisieren. Die Isolierung der strukturell sehr ähnlichen Cerebroside gelang durch Reversed-Phase-HPLC. Negativ-FABMS-Spektrometrie ließ sich erfolgreich zur Molmassen-Bestimmung der Cerebroside einsetzen.
    Notizen: Six new cerebrosides (ceramide monohexosides), acanthacerebroside A (1), B (2), C (3), D (4), E (5), and F (6) were isolated from the water-insoluble lipid fraction of the chloroform-methanol extract of the starfish Acanthaster planci. On the basis of chemical and spectral evidences, they were characterized as 1-O-(β-D-glucopyranosyl)-substituted (1S,3S,4R)-2-[(2R)-2-hydroxytetracosanoylamino]-1,3,4-hexadecanetriol (1), (2S,3S,4R)-2-[(2R)-2-hydroxyhexadecanoylamino]-1,3,4-docosanetriol (2), (2S,3S,4R,13E)-2-[(2R)-2-hydroxyhexadecanoylamino]-13-docosene-1,3,4-triol (3), (2S,3R,4E,10E)-2-[(2R)-2-hydroxydocosanoylamino]-4,10-octadecadiene-1,3-diol (4), (2S,3R,4E,10E)-2-[(2R)-2-hydroxydocosanoylamino]-4,10-octadecadiene-1,3-diol (5), and (2S,3R,4E,10E)-2-[(2R)-2-hydroxytetracosanoylamino]-4,10-octadecadiene-1,3-diol (6). Reversed-phase HPLC was effective to isolate these cerebrosides revealing the very close resemblance in structure. Negative FABMS spectrometry was useful in providing information on the molecular mass of the cerebrosides.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jlac.198819880105
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