ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
  • 1
    Electronic Resource
    Electronic Resource
    Haloaldehyde polymers, 40Part 39, cf.15a.. Stereostructure of chloral oligomers prepared with lithium tert-butoxide: Helical conformation of the linear isotactic oligomers in crystal and in solution (1990)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 191 (1990), S. 557-569 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The stereostructures of linear chloral oligomers were determined by X-ray single crystal analysis. The chloral oligomers from dimer to pentamer were isolated by distillation and by GPC fractionation from the oligomer mixture prepared with t-BuOLi initiation and acetate endcapping. The dimer fraction was a diastereomeric mixture of the racemo (1) and meso (2) isomers, while the trimer, tetramer and pentamer fractions each contained a single diastereomer (3, 4 and 5). The single crystals of 2, 3, 4 and 5 grown from methanol solutions belong to the space groups P1-, P21/n, P21/a and Pca21, respectively. X-ray analyses showed that the acetal backbones of 2, 3 and 4 consist exclusively of meso dyads. The backbone arrangements of 2, 3 and 4, are essentially identical and approximate the repeat gauche(+)-skew(-) sequences from the t-BuO group to the acetyl terminal group (for S-configurations). The conformation of (S,S,S,S)-4 is very similar to a unit sequence of a 4/1-helical structure of isotactic polychloral with left-handed helicity. The axis of the helix is parallel to the c-axis of the crystal, and the repeat distance is 4,81 Å. The conformations of the acetal backbones of 4 and 5 in solution were also investigated by NMR spectroscopy, on the basis of dihedral angle dependence of 3JC—O—C—H coupling constants.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1990.021910311
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Haloaldehyde polymers, 43.Part 42, cf. G. D. Jaycox, O. Vogl, J. Am. Chem. Soc., submitted.. Structure of 2-bornyloxy-terminated chloral oligomers (1991)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 192 (1991), S. 35-48 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Oligomerization of trichloroacetaldehyde (chloral) was carried out with the lithium salt of (1 S, 2 R, 4 S)-(-)-borneol as the initiator. The unimer and dimer fractions consisted of two and four diastereomers, respectively; the individual isomers were isolated from the fractions by crystallization from methanol or by high performance liquid chromatography. The X-ray single-crystal analysis showed that the major isomer in the unimer fraction is the (R)-form which has the acetal carbon in (R)-configuration. The diastereomeric ratios were determined by 1H NMR as R/S = 57/43 for the unimers and RS/SR/RR/SS = 34/25/23/18 for the dimers. The conformations of the meso-dimers [(R,R)- and (S,S)-isomers] in the crystalline form corresponded to a half turn of the 41-helix of isotactic polychloral, whereas the conformations of the racemo-dimers (the (R,S)- and (S,R)-isomers) were different from the helical structure in the crystal and in solution. The trimer fraction consisted of six of the eight possible diastereomers; among these isomers, the mm isomers (the (R,R,R)- and (S,S,S)-isomers) were highly predominant. The amount of the (R,R,R)-trimer formed was only slightly larger than that of the (S,S,S)-isomer. (a) Part 42, cf. G. D. Jaycox, O. Vogl, J. Am. Chem. Soc., submitted.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1991.021920104
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Functional polymers, 32Part 31: cf. S. J. Li and O. Vogl, Polym. Bull., in press.. 5-Methoxy- and 5-hydroxy-2H-benzotriazol-2-yl mono- or disubstituted resorcinols or phloroglucinolsThis paper is dedicated to Prof. Dr. J. Schurz on the occasion of his 60th birthday with best personal wishes (1984)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 185 (1984), S. 2497-2509 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Four new 5-methoxy-2H-benzotriazol-2-yl mono- or di-substituted resorcinols and phloroglucinols 5a, b and 6a, b were synthesized by reaction of resorcinol or phloroglucinol with 4-methoxy-2-nitrobenzenediazonium chloride in a 1:1 or 1:2 mole ratio and subsequent reductive cyclization with zinc and sodium hydroxide. The methoxy groups of all four compounds were cleaved with dry hydrogen bromide gas in dimethylformamide leading to the corresponding hydroxyl derivatives 7a, b and 8a, b in nearly quantitative yields. Unlike the reaction of phloroglucinol with a large excess of 2-nitrobenzenediazonium chloride, which gave the trisubstituted product, with 4-methoxy-2-nitrobenzenediazonium chloride no phloroglucinol derivative with three 5-methoxy-2H-benzotriazol-2-yl groups could be obtained. All the resulting products were characterized by their IR, 1H, and 13C NMR, and UV spectra. The resorcinol derivatives (both methoxy- and hydroxy-) Showed λmax of 345 nm and an absorption coefficients as high as 4 · 104 l · mol-1 · cm-1, and the phloroglucinol derivatives a λmax of 350 nm and an absorption coefficient as high as 4,5 · 104 l · mol-1 · cm-1.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1984.021851202
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Helix-sense-selective polymerization of phenyl[bis(2-pyridyl)]methyl methacrylate and chiral recognition ability of the polymer (1993)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 31 (1993), S. 2721-2728 
    Details
    ISSN: 0887-624X
    Keywords: phenyl[bis(2-pyridyl)]methyl methacrylate ; optically active polymer ; solvolysis ; chiral stationary phase ; anionic polymerization ; (S)-(+)-1-(2-pyrrolidinylmethyl)pyrrolidine ; optical resolution ; high performance liquid chromatography ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel monomer, phenyl[bis(2-pyridyl)]methyl methacrylate (PB2PyMA), was synthesized. The solvolysis rate of PB2PyMA measured in CDCl3-CD3 OD [1/1 (v/v)] by 1H-NMR spectroscopy at 35°C was much smaller than those of triphenylmethyl methacrylate (TrMA) and diphenyl-2-pyridylmethyl methacrylate (D2PyMA). PB2PyMA was anionically polymerized with the complexes of organolithiums with (-)-sparteine (Sp), (S,S)-(+)-and (R,R)-(-)-2,3-dimethoxy-1,4-bis(dimethylamino)butanes[(+)-and (-) -DDB], and (S)-(+)-1-(2-pyrrolidinylmethyl) pyrrolidine (PMP) in toluene at low temperature. The polymers obtained with Sp and DDB complexes showed low optical activity. PMP complexes, particularly that with N,N′-diphenylethylenediamine monolithium amide, were effective in synthesizing a polymer of high optical rotation ([α]25365 ∼ +1350°) which was comparable to those of poly(TrMA) and poly(D2PyMA) with one-handed helical structure. The optical rotation of poly(PB2PyMA) in a mixture of CHCl3 and 2,2,2-trifluoroethanol (9/1, v/v) slowly decreased with time. Optically active poly(PB2PyMA) coated on macroporous silica gel was able to resolve racemic compounds as a chiral stationary phase for high-performance liquid chromatography. © 1993 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1993.080311107
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Helix-sense-selective copolymerization of phenyl[bis(2-pyridyl)]methyl methacrylate, diphenyl(2-pyridyl)methyl methacrylate and triphenylmethyl methacrylate with chiral anionic initiators (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2127-2133 
    Details
    ISSN: 0887-624X
    Keywords: phenyl[bis(2-pyridyl)]methyl methacrylate ; (S)-(+)-1-(2-pyrrolidinylmethyl)pyridine ; anionic asymmetric copolymerization ; optically active copolymer ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Optically active poly[triphenylmethyl methacrylate-co-phenyl[bis(2-pyridyl)]methyl methacrylate] (poly[TrMA-co-PB2PyMA], poly[diphenyl(2-pyridyl)methyl methacrylate-co-phenyl[bis(2-pyridyl)]methyl methacrylate] (poly[D2PyMA-co-PB2PyMA]), and poly[triphenylmethyl methacrylate-co-diphenyl(2-pyridyl)-methyl methacrylate] (poly[TrMA-co-D2PyMA]) were prepared by helix-sense-selective copolymerization with complexes of organolithium with (-)-sparteine [(-)Sp],(S, S)-(+)- and (R, R)-(-)-2,3-dimethoxy-1,4-bis(dimethylamino)butane [(+)- and (-)DDB], and (S)-(+)-2-(1-pyrrolidinylmethyl)pyridine [(+)PMP] as anionic initiators in toluene at low temperature. The copolymers obtained with (-)Sp and (+)DDB or (-)DDB complexes of organolithium showed low optical activity, but to [(+)PMP] complex with N,N′-diphenyleneamine monolithium amide [(+)PMP-DPEDA-Li)] was effective in synthesizing copolymers of high optical rotation ([α]25D about +320 to + 370°) which were comparable to those of corresponding homopolymers with one-handed helical structure. The optical rotations of poly[TrMA-co-PB2PyMA] and poly[TrMA-co-D2PyMA] were much more stable than that of poly(D2PyMA) or poly(PB2PyMA) in a solution of CHCl3-2,2,2-trifluoroethanol (10 : 1, v/v) at 25°C, but optical rotation of poly[D2PyMA-co-PB2PyMA] slowly decreased with time in the same conditions. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2127-2133, 1998
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 6
    Electronic Resource
    Electronic Resource
    Chiral dendrimers with axial chirality (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 10 (1998), S. 661-666 
    Details
    ISSN: 0899-0042
    Keywords: chiral dendrimers ; dendrimers ; axial chirality ; (R)-(+)-1,1′-bi-2,2′-naphthol ; optical rotation ; circular dichroism ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis and optical activity of novel chiral dendrimers with axial chirality are reported. The dendrimers were constructed by coupling of the polyether dendritic bromides with (R)-(+)-1,1′-bi-2-naphthol (1). The uniform (2, 3, 4) and non-uniform double-O-alkylated (8, 9, 10) as well as mono-O-alkylated (5, 6, 7) products were thus obtained. These chiral molecules were characterized by 1H- and 13C-NMR, elemental analysis, optical rotation, adsorption spectra, and circular dichroism. It was found that the specific rotation decreases with the increase of the number of generation for each group of dendrimers (2-4, 5-7, and 8-10, respectively). In terms of the molar rotation, it was quite different; the molar rotation increased sharply for dendrimers, 2-4, but only slightly for dendrimers 5-7. The dihedral angle change of bi-naphthyl in the synthesized dendrimers was discussed based on the CD spectra. Chirality 10:661-666, 1998. © 1998 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 7
    Electronic Resource
    Electronic Resource
    Block copolymerization of triphenylmethyl methacrylate with other methacrylates using (-)-sparteine/9-fluorenyllithium as an initiator (1997)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 198 (1997), S. 279-290 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Diblock and triblock copolymerization of triphenylmethyl methacrylate (TrMA) with methyl methacrylate (MMA), butyl methacrylate (BuMA), benzyl methacrylate (BzMA) or diphenylmethyl methacrylate (DPMMA) in the presence of the chiral anionic complex initiator, (-)-sparteine/9-fluorenyllithium, were investigated. The resulting block copolymers show high specific rotation and were characterized by means of gel-permeation chromatography, scanning electron microscopy, nuclear magnetic resonance, circular dichroism spectra and thermal analysis.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1997.021980205
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Studies on helix-sense-selective copolymerization based on triphenylmethyl methacrylate (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 195 (1994), S. 1177-1187 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Helix-sense-selective copolymerizations based on triphenylmethyl methacrylate (TrMA) with methyl methacrylate (MMA), benzyl methacrylate (BzMA) and diphenylmethyl methacrylate (DPMMA) in the presence of the chiral anionic complex initiator (-)-sparteine/9-fluorenyl-lithium (1) were investigated. The studies concentrated on the stereoregularity of the copolymers, the relative reactivity of the monomers, the specific rotation of the copolymers and the influence of the solvent on the copolymerization. The results show that the match of TrMA with MMA of smaller size would favour the form of the copolymer with isotactic one-handed helix having higher specific rotation as compared with BzMA ad DPMMA in toluene, but the TrMA/MMA copolymer obtained in tetrahydrofuran possessed a very low specific rotation because of the action of the polar tetrahydrofuran on the anion complex.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1994.021950406
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Poly(methacrylates) with different kinds of dendritic moieties as side groups (1996)
    Weinheim : Wiley-Blackwell
    Macromolecular Rapid Communications 17 (1996), S. 401-407 
    Details
    ISSN: 1022-1336
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Alkyl methacrylate monomers with three kinds of dendritic fragments as alkyl groups, two kinds of Fréchet-type and a new type with 3,5-diphenoxybenzyl as first generation, were prepared by reaction of the corresponding dendritic bromides with methacrylic acid in good yield and were homopolymerized with a radical initiator. Polymers with side groups in first generation had a degree of polymerization (P̄n) of 17-24, markedly higher than those with side groups in second generation, P̄n ≈ 6-7.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/marc.1996.030170606
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Functional polymers. XXX: 2(2,4,6-trihydroxyphenyl) 2h-benzotriazole [2(2h-benzotriazole-2-yl)-1,3,5-trihydroxybenzene] and benzotriazole-substituted dihydrocoumarinsPart XXIX: S. J. Li, A. Gupta, A. C. Albertsson, W. Bassett, jr., and O. Vogl: Polymer Bulletin 12 (1984) 237.Dedicated to Professor Dr. habil. Burkart Philipp on the occasion of his 60th birthday (1985)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 36 (1985), S. 81-86 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Unter optimalen Reaktionsbedingungen wurden 2(2H-Benzotriazol-2-yl)-1,3,5-trihydroxy-benzen bzw. 2(2H-4′-Methoxybenzodiazol-2-yl)-1,3,5-trihydroxy-benzen als einziges Reaktionsprodukt der Umsetzung von 2-Nitrophenyl-diazoniumchlorid bzw. 4-Methoxy-2-nitrophenyldiazoniumchlorid mit Phloroglycin und anschließender reduktiver Cyclisierung der Azoverbindung erhalten. Veresterungsversuche der 5-Hydroxygruppe ergaben nicht die erwartete 5-Acryloxyverbindung, sondern über eine Michael-Kondensation der Methylengruppe des Acrylatrestes mit dem Kohlenstoff in 3-Stellung 6(2H-Benzotriazol-2-yl)-5,7-dihydroxy-3,4-dihydrocumarin bzw. das 4′-Methoxyderivat. Die 3,4-Dihydrocumarinverbindung wurde charakterisiert, die Hydrolyse führt zu 3(2H-Benzotriazol-2-yl)-2,4-dihydroxy-hydrocumarsäure. Die Modellverbindungen 5,7-Dihydroxy-3,4-dihydrocumarin und 7-Hydroxy-3,4-dihydrocumarin wurden auf gleichem Wege aus Phloroglycin bzw. Resorcin dargestellt und charakterisiert.
    Notes: 2(2 H-Benzotriazole-2-yl)-1-3,5-trihydroxybenzene was synthesized by improved reactions as the sole product of 2-nitrobenzenediazonium or 4-methoxy-2-nitrobenzenediazonium chloride condensation and phloroglucinol followed by reductive cyclization of the azo compound. Attempted esterification of the 5-hydroxy group did not yield the expected 5-acryloxy compound, but rather 6(2 H-benzotriazole-2-yl)-5,7-dihydroxy-3,4-dihydrocoumarin, and 6(2H-4′-methoxy-benzotriazole-2-yl)-5-7-dihydroxy-3,4-dihydrocoumarin, through a Michael-type condensation of the methylene group of the acrylate to the carbon in 3 position; the dihydrocoumarin was characterized and hydrolyzed to 3(2 H-benzotriazole-2-yl)-2,4-dihydroxymelilotic acid. The model compound 5,7-dihydroxy-3,4-dihydrocoumarin and 7-hydroxy-3,4-dihydrocoumarin was also synthesized from resorcinol and phloroglucinol and characterized.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1985.010360205
    Location Call Number Expected 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...