GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Chemistry  (9)
Document type
Keywords
Publisher
Years
  • 1
    Electronic Resource
    Electronic Resource
    Nucleotides. Part LPart IL:[1]. Aglycone protection by the (2-dansylethoxy)carbonyl (= {2-{[5-(dimethylamino)naphthalen-l-yl]sulfonyl}ethoxy}carbonyl; dnseoc) group a new variation in oligodeoxyribonucleotide synthesis (1997)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 80 (1997), S. 200-212 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The (2-dansylethoxy)carbonyl (= {2-{[5-(dimethylamino)naphthalen-l-yl]sulfonyl}ethoxy}carbonyl; dnseoc) group was employed for protection of the amino functions of the aglycone residues. The lactam function of 2′-deoxyguanosine was on the one hand unprotected and on the other hand alkylated at O6 of the aglycone with the 2-(4-nitrophenyl)ethyl (npe) and 2-(phenylsulfonyl)ethyl (pse) group, respectively. The syntheses of monomeric building blocks, both phosphoramidites and nucleoside- functionalized supports, are described for the three common 2′-deoxynucleosides (2′-deoxycytidine, 2′-deoxyadenosine, 2′-deoxyguanosine). As kinetic studies with the tritylated nucleosides showed, the dnseoc group is more labile towards DBU cleavage than the corresponding 2-(4-nitrophenyl)ethyl-(npe) and [2-(4-nitrophenyl)ethoxy]carbonyl(npeoc)-protected analogues (see Table 2). These results were confirmed by the very fast deprotection rate of the dnseoc groups at some oligonucleotides.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19970800118
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of poly[2,3,9,10,16,17,23,24-octakis(dodecyloxycarbonyl)phthalocyaninatogermoxane] (1993)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 194 (1993), S. 493-500 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In this article we describe the preparation of poly[2,3,9,10,16,17,23,24-octakis(dodecyloxycarbonyl)phthalocyaninatogermoxane] by thermal polycondensation of 2,3,9,10,16,17,23,24-octakis(dodecyloxycarbonyl)phthalocyaninatogermanium dihydroxide, and its characterization. The average molar mass of the resulting polymer was determined. High molar masses are assessible, e.g., M̄w = 360000 g/mol, M̄n = 140000 g/mol, at moderate temperature for the polycondensation (200°C). The polymer shows a liquid-crystalline phase in an extremely large temperature range. Furthermore, Langmuir-Blodgett films (LB films) of the polymer and of the monomer were prepared and characterized. In LB films the phthalocyanine rings are preferentially oriented normal to the dipping direction.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1993.021940212
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Synthesis of high-molecular-weight poly(dimethylsiloxane) of uniform size by anionic polymerization, 1. Initiation by a monofunctional lithium siloxanolate (1992)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 193 (1992), S. 2453-2466 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An improved procedure for the anionic polymerization of hexamethylcyclotrisiloxane (D3) initiated by a monofunctional lithium derivative is reported. The initiator seeding solution is preferably prepared in benzene, and tetrahydrofuran is used as a cosolvent which makes the presence of additional promoters useless. The main advantage of this procedure is that it delays the appearance of bimodality which is believed to result from a sudden change in aggregate molecularity during the course of the reaction. Applying this method, poly(dimethylsiloxane) samples having a single functional endgroup and possessing high molecular weights and narrow molecular weight distributions (1,03 ≤ M̄w/M̄n ≤ 1,06) were prepared on the 100 g scale.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1992.021930928
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Silylation of poly(vinyl alcohol) with hexamethyldisilazane in liquid ammonia (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 33 (1995), S. 1119-1124 
    Details
    ISSN: 0887-624X
    Keywords: poly(vinyl alcohol) ; silylation ; hexamethyldisilazane ; liquid ammonia ; kinetics ; properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Silylation of poly(vinyl alcohol) has been performed with hexamethyldisilazane in liquid ammonia in an autoclave. This novel procedure has the advantage that the educt, the reagent, and the product are soluble in ammonia, which works under homogeneous conditions. No salt like by-products are formed and no tedious purification of the product is necessary. The degree of silylation has been adjusted through the ratio of silylating agent to hydroxy groups. Random incorporation of trimethylsilyl groups was proven by the linear dependence of the glass transition temperature from the degree of silylation and the solubility of the partially silylated material. Quantitative investigation of the silylation reaction showed first-order kinetics for the initial and final stages of the reaction indicative of a reaction where k1 〉 k2 〉 k3. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1995.080330714
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Origins of the differences between the circular dichroism of DNA and RNA: Theoretical calculations (1973)
    New York : Wiley-Blackwell
    Biopolymers 12 (1973), S. 201-221 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Theoretical calculations of the circular dichroism of double-helical DNA and RNA by the method of Johnson and Tinoco were performed in order to investigate the origins of the optical activity spectral differences between these polynucleotides. Calculations were performed using transition moment directions arising from molecular orbital calculations as well as a transition moment directions in agreement with experimental directions. The results of these calculations indicate that the conservative circular dichroism spectrum of B-form DNA and the nonconservative spectrum of RNA (and A-form DNA) arise as a consequence of the distance between the paired bases and the helix axis. The negative nonconservative spectrum of C-form DNA was calculated and shown also to result from the distance of the paired bases from the helix axis. Several other conspicuous geometric parameters of DNA and RNA were investigated and were found to be less significant in their effects upon the spectral differences. Theoretical calculations on a four-stranded DNA model which has paired bases similarly related to the helix axis as RNA and A-form DNA was found to yield a low intensity, nonconservative circular dichroism spectrum.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1973.360120119
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Double-helical DNA and RNA circular dichroism. Calculations on base-sugar-phosphate helix interactions (1974)
    New York : Wiley-Blackwell
    Biopolymers 13 (1974), S. 977-986 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Theoretical calculations of the near ultraviolet (uv) circular dichroism of double-helical DNA and RNA models were performed in order to evaluate the effects, on the calculated circular dichroism, of including the interactions of near uv quantum transitions of the nucleic acid bases with classical polarizable bonds of the sugar-phosphate backbone. Double-helical models (A-form, B-form, and C-form DNA and RNA-11) from X-ray diffraction data were used in the calculations. The results indicate that the contributions to the circular dichroism in the near uv region, of these types of interactions, provide calculated spectra that are slightly altered from calculated spectra when only base-base transition interactions were considered.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1974.360130512
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Probing DNA quaternary ordering with circular dichroism spectroscopy: Studies of equine sperm chromosomal fibers (1977)
    New York : Wiley-Blackwell
    Biopolymers 16 (1977), S. 573-582 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Studies are described which strongly support a cholesteric liquid crystal-like quaternary structure for the DNA molecules of a biologically native chromosomal preparation from equine sperm cells. Discrete chromosomal fibers released from the head pieces of equine spermatozoon cells were prepared intact and probed for liquid crystalline ordering using reflectance and linear dichroism spectroscopy. Assuming cholesteric liquid crystalline order for the DNA molecules within the chromatin fibers, parameters measured experimentally were used to calculate the circular dichroism (CD) of the fibers. The calculated results compare remarkably well with the experimentally measured CD of the sperm chromosomal fibers and suggest a specific cholesteric liquid crystal-like quanternary structural ordering of DNA molecules in equine sperm chromatin fibers. The potential of CD spectroscopy as a tool for the study of long-range ordering of macromolecules is discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1977.360160308
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Silylation of cellulose and low-molecular-weight carbohydrates with hexamethyldisilazane in liquid ammonia (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 18 (1997), S. 515-522 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Silylation of cellulose and some low-molecular-weight hydroxy compounds (1,2-propanediol, D-glucose, methyl α-D-glucoside, sucrose and β-cyclodextrin) has been performed with hexamethyldisilazane (HMDS) in liquid ammonia at elevated temperature in an autoclave. No salt-like by-products are formed and no tedious purification of the products is necessary. As indicated by size-exclusion chromatography the silylation of cellulose with HMDS/NH3 proceeds without degradation of the polymer chain. The degree of silylation of the trimethylsilylcellulose obtained is higher than with other silylation procedures reported in the literature. The temperature/composition diagram of HMDS/NH3 proved complete miscibility above 24°C.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1997.030180610
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Acylation of (partially) silylated poly(vinyl alcohol)s with acyl chlorides. Vinyl chloride/vinyl ester copolymers by polymer analogous reaction (1996)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 197 (1996), S. 3463-3471 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Acylation of (partially) silylated poly(vinyl alcohol) with acyl chlorides and anhydrides was investigated under different conditions. In the presence of an acid acceptor (triethylamine) at temperatures below 50°C selective acylation of hydroxy groups was observed in agreement with literature data. At elevated temperature (160°C) without the use of an acid acceptor hydroxy and trimethylsiloxy groups react in an unselective manner. In addition, significant amounts of chlorine were found in the resulting polymers under these conditions, though no double bonds were detected. A polymer analogous reaction without incorporated chlorine was achieved with benzoic anhydride as acylating agent. Random distribution of chlorine and benzoyloxy groups most likely is obtained.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1996.021971031
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...