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  • 1
    Electronic Resource
    Electronic Resource
    Nuclear magnetic resonance and stereoregularity of PVC (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 19 (1975), S. 1227-1241 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The decoupled α-proton spectrum of PVC was examined using a 220 MHz NMR spectrometer. All of the ten possible pentads were detected and an assignment is given based on Bernoullian statistics. This assignment is in general agreement with conclusions reached by previous workers except for some modifications in the heterotatic resonances. Triad tacticity data were obtained from the pentads and were used to estimate the differential enthalpy and entropy changes for bulk PVC polymerized in the temperature range 70°C to -50°C.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1975.070190503
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis and rearrangement of triazinoquinazolines (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 5 (1994), S. 97-101 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Selective syntheses of triazino[4,3-a]quinazolines 3a-e and their isomeric triazino[3,2-b]quinazolines 4a-e by cyclization of the appropriate α-keto acid hydrazones 2a-e under different reaction conditions are described. The angular triazinoquinazolines 3a-e were readily rearranged to the corresponding linear isomers 4a-e when heated in acetic anhydride in the presence of sodium acetate. This rearrangement was proposed to proceed via the intermediate isomeric triazino[3,4-b]quinazolines 5a-e. The N-methyl derivative 10 (of the intermediate 5b) was prepared and rearranged to 11, which is the N-methyl derivative of 4b.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hc.520050203
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  • 3
    Electronic Resource
    Electronic Resource
    Stereospecific synthesis of 6,7-dihydro-5H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 5 (1994), S. 321-325 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of 3-mercapto-4-arylideneamino-1,2,4-triazoles 2b-d, 3a-d with ethyl bromoacetate and/or phenacyl bromide in hot DMF and triethylamine affords the stereochemically pure 7-acyl-6-aryl-6,7-dihydro-5H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines 4b-d, 5a-d, 6b,d in which the consecutive hydrogen atoms N(5)H-C(6)H-C(7)H are cis to each other. This stereochemistry was determined by 1H NMR spectroscopy and confirmed by comparison with the spectrum of 3,6-diphenyl-6,7-dihydro-5H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazine 10. The latter was prepared by NaBH4 reduction of 3,6-diphenyl-5H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazine 9. The reported reactions offer two interesting stereospecific syntheses of the condensed heterocyclic compounds.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hc.520050402
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  • 4
    Electronic Resource
    Electronic Resource
    Synthetic approaches toward macrocyclic sulfonyl crown formazans (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 7 (1996), S. 215-219 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Coupling of diazonium salts with ethyl sulfonylpyruvates 1-3 or arenesulfonylacetic acids 14,15 afforded good yields of the corresponding 1,5-symmetrically disubstituted-3-sulfonylformazans 4-11. The new sulfonyl macrocyclic crown formazans 25-32 were prepared by coupling of the appropriate bisdiazonium salts 22-24 with compounds 1-3 or 14,15. © 1996 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Morphological effects of diabetes on the granular ducts and acini of the rat submandibular gland (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 27 (1994), S. 61-70 
    Details
    ISSN: 1059-910X
    Keywords: Salivary gland ; Diabetes ; Insulin ; Electron microscopy ; Streptozotocin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Effects of experimental diabetes on rat submandibular glands have been documented, but earlier reports suggested that diabetes caused an extensive cellular degeneration and a replacement of the parenchymal cells by fibrous connective tissue. Such observations, however, are difficult to reconcile with the relatively normal physiological responsiveness of the gland (Anderson and Suleiman, 1989). This study, therefore, reexamined the histological, histochemical and ultrastructural effects of streptozotocin-induced diabetes on rat submandibular glands. The tissues were examined at 3 weeks, and 3 and 6 months after the induction of diabetes, and compared with glands from age-matched controls by both light and electron microscopy. Light microscopically, the proportional volumes of the acini and granular ducts remained constant in control rats at about 48% and 38% respectively. In diabetic animals the volume density of the acini increased progressively to 62%, whereas that of the granular ducts decreased to 20%. The diameter and number of granular ducts were reduced in diabetic animals, but acinar cell profile area was only affected 6 months after the induction of diabetes. Ultrastructurally, there was an accumulation of lipid in the acinar cells and, with increasing duration of diabetes, the number of autophagic structures in both the acini and the granular ducts increased. Although there was evidence of some cellular degeneration it was never excessive. Morphometry showed that the volume density of secretory granules within the acinar cells was unaffected, but there was a significant reduction in the volume density of secretory granules within the granular ducts. Thus, in the rat submandibular gland the greatest effect of streptozotocin-induced diabetes was to cause hypotrophic changes in the cells of the granular ducts. The relative contributions of a direct effect of insulin insufficiency and the hypogonadal effects of diabetes, however, are not known. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070270105
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  • 6
    Electronic Resource
    Electronic Resource
    Synthesis of chromophoric bisazocrowndilactamsDedicated to Prof. Dr. Shigeru Oae on the occasion of his seventy-fifth birthday. (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Heteroatom Chemistry 6 (1995), S. 183-187 
    Details
    ISSN: 1042-7163
    Keywords: Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The coupling of 1,2-bis(o-hydroxybenzamido)ethane 1 with two equivalents of the appropriate arenediazonium chloride in aqueous sodium hydroxide afforded the corresponding 1,2-bis(2-hydroxy-5-arylazobenzoylamino)ethanes 4-6. The latter were converted to the corresponding dipotassium salts 7-9, which were reacted with the appropriate dihalo compound or ditosylate in boiling DMF to give the corresponding 14-17-membered macrocyclic bis-azo-crowndilactams 10-18 in 58-65% yields. Compound 14 was N-alkylated to give the corresponding N,N′-dibenzyl derivative 19.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hc.520060213
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  • 7
    Electronic Resource
    Electronic Resource
    Bulk polymerization of vinyl chloride (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 783-799 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The bulk polymerization of vinyl chloride initiated by AIBN at temperature levels of 30°, 50°, and 70°C has been studied. Molecular weight averages and distribution (MWD) were measured by gel permeation chromatography. A model has been proposed which accurately predicts conversion to high levels and MWD. Molecular weight measurements show that transfer to monomer plays the important role in controlling molecular weight averages. Disproportionation is probably the dominant mode of termination.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070160321
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  • 8
    Electronic Resource
    Electronic Resource
    Molecular aggregation in poly(vinyl chloride). A novel analytical technique (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 1093-1101 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A novel experimental technique based on gel permeation chromatography (GPC) has been developed for the measurement of molecular aggregation in poly(vinyl chloride) (PVC). PVC having a range of syndiotacticity was synthesized using polymerization temperatures of 30-70°C. Tacticity and molecular aggregation of these PVC samples were measured by NMR and GPC, respectively. The temperature dependence of molecular aggregation was found to be much greater than that of tacticity. This GPC technique is inherently more sensitive than NMR in the temperature range normally employed for commercial production of PVC. It should find extensive use in the control of PVC reactors and in PVC processing.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1972.070160504
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  • 9
    Electronic Resource
    Electronic Resource
    Molecular aggregation in poly(vinyl chloride). III. Role of molecular structure (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 19 (1975), S. 2179-2185 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The present study offers a visualization of the process of molecular aggregation in PVC polymerized at low temperatures in bulk. “Kinks” along with the chains are responsible for molecular entanglement with subsequent microcrystallization of the syndiotactic sequences. The crystallites act as bonding nuclei. The “kinks” are the result of the different chain conformations of isotactic and syndiotactic sequences. The number of “kinks” increases on lowering the polymerization temperature both because the chains are longer and also because of the more frequent switching between isotactic and syndiotactic placements.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1975.070190811
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  • 10
    Electronic Resource
    Electronic Resource
    Studies on aminoazoles: Synthesis of Pyrazolo[1,5-a]-pyrimidines and their aza derivatives (1989)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 331 (1989), S. 466-474 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of 4-arylazo-3-aminopyrazol-5-ones (1a-i) with α,β-unsaturated nitriles, active methylene reagents and nitrile imines are reported. They lead to new polyfunctional derivatives of pyrazolo[1,5-a]pyrimidine (5a-c, 6, 10a-i, 13a-c, 14a-c, 17a-d, 15), pyrazolo-[5,1-c]-1,2,4-triazine (22a-i) and pyrazolo[5,1-c]-1,2,4-triazole (25a-c).The structures of these products and the mechanisms of their formation are reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19893310318
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