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  • 1
    Electronic Resource
    Electronic Resource
    Conformational analysis. XXXI. Conformational equilibria of 1,3-dioxanes with polar substituents at C-5 (1976)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 98 (1976), S. 956-965 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00420a015
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  • 2
    Electronic Resource
    Electronic Resource
    Ring inversion barrier in 5,5-difluoro-1,3-dioxane (1973)
    s.l. : American Chemical Society
    The @journal of organic chemistry 38 (1973), S. 4079-4081 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00987a033
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  • 3
    Electronic Resource
    Electronic Resource
    PMR-Spektren einiger Alkoxy-9-chlor-6-nitroacridine (1978)
    Springer
    Monatshefte für Chemie 109 (1978), S. 1393-1401 
    Details
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The spectra of some 9-chloro-6-nitroacridines with methoxy substituents in position 1,4; 2,4; 3,4; 2,3; and ethoxy substituents in positions 1, 2, 3, were recorded. The influence of electron releasing alkoxy groups and electron withdrawing nitro groups on chemical shifts of protons in the 9-chloroacridinic cycle was discussed and PMR parameters were determined, comparatively with those of acridine and 9-chloroacridine. Good agreement between calculated and experimental values is observed. The spectrum of 9-chloro-1,2,3-triethoxyacridine shows for the four protons of the ringC. (H-5, H-6, H-7, H-8) anAMNX coupling pattern whose parameters were determined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00906052
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  • 4
    Electronic Resource
    Electronic Resource
    Neue Molekülverbindungen des β-1,2,3,4,5,6-Hexachlorcyclohexans (1978)
    Springer
    Monatshefte für Chemie 109 (1978), S. 1403-1412 
    Details
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Eight new molecular compounds between β-1,2,3,4,5,6-hexachlorocyclohexane (β-HCH) and some heterocyclic salts (hydrochlorides of β- and γ-picoline, 2,4,6-collidine, α,α′-bipyridine, isoquinoline, acridine, 9-phenylacridine, and 2,4,6-triphenylpyrylium perchlorate), with the molecular ratio 1∶2, were synthesised and described by means of spectroscopic (IR, UV, NMR) and X-ray-diffraction methods. Some of the molecular compounds may be used for quantitative separation of the heterocyclic salts from complex mixtures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00906053
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  • 5
    Electronic Resource
    Electronic Resource
    Stereochemie und1H-NMR-Spektren einiger Spiro-1,3-Dioxane (1982)
    Springer
    Monatshefte für Chemie 113 (1982), S. 565-572 
    Details
    ISSN: 1434-4475
    Keywords: Formaldehyde generating reagent ; Solvent shifts in1H-nmr ; Spiranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Mono and dispiro-1,3-dioxanes (1–3) were synthesized by the condensation of 1,2-, 1,3- and 1,4-cyclohexanedione, respectively (4–6) with bis-(hydroxymethyl)-malonic ester (7). The1H-NMR spectra prove for the mono- (2) and dispiro-1,3-dioxane (3) the existence of conformational equilibria and for the monospiro-1,3-dioxane (1) a “fixed” structure. C6D6 causes a remarkable solvent shift effect in the NMR spectra separating a superposed complex coupling pattern (in CDCl3) in two well resolved AB doublets and two AX quartets. TheE-oxime of the monospiro-1,3-dioxanone (1) represents also a “fixed” structure. Bis-(hydroxymethyl)-malonic ester (7) is a formaldehyde generating agent in the condensation reaction of dimedone with the diol7.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00800263
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  • 6
    Electronic Resource
    Electronic Resource
    Stereochemie und1H-NMR-Spektren einiger vom Pentaerythrit abgeleiteten Spiro-1,3-dioxane (1989)
    Springer
    Monatshefte für Chemie 120 (1989), S. 735-742 
    Details
    ISSN: 1434-4475
    Keywords: Spiro-1,3-dioxanes ; Pentaerythritol (a)ketals ; Conformational analysis ; Aromatic solvent induced shift — ASIS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Mono- and trispiro-1,3-dioxanes with mobile, fixed and “semimobile” structures were obtained by the condensation reaction of pentaerythritol with aldehydes and symmetrical or unsymmetrical ketones. The conformational analysis of the obtained compounds was undertaken by means of1H-NMR spectroscopy. The spiro-1,3-dioxanes obtained with aldehydes or nonsymmetrical ketones represent fixed (“anancomeric”) structures. Ketalisation with 4-t-butyl-cyclohexanone leads to a “semimobile” structure of a trispiro-1,3-dioxane in which the two marginal cyclohexanic rings are fixed, while the two middle ones are mobile, continuously flipping at room temperature. The solvent effect on the NMR spectra is also discussed. Utilisation of benzene-d 6 makes it possible to interpret some of the complex spectra with superposed signals on the basis of the aromatic solvent induced shift (ASIS).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00809966
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  • 7
    Electronic Resource
    Electronic Resource
    The Stereochemistry of Some New Flexible 2,2,5,5-Tetrasubstituted 1,3-Dioxanes (1998)
    Springer
    Monatshefte für Chemie 129 (1998), S. 723-733 
    Details
    ISSN: 1434-4475
    Keywords: Keywords. Flipping 1 ; 3-dioxanes; Prostereogenic carbon atoms; NMR discrimination of pro-R ; pro-S ; pro-cis ; and pro-trans groups; NMR spectra with chiral shift reagents.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  Die Stereochemie einiger neuer 2,2,5,5-tetrasubstituierter 1,3-Dioxanderivate wurde untersucht. Spezielle Fälle von Prostereoisomerie sowie die NMR-spektroskopische Unterscheidung der pro-R-, pro-S-, pro-cis- und pro-trans-Substituenten werden diskutiert.
    Notes: Summary.  The stereochemistry of some new 2,2,5,5-tetrasubstituted 1,3-dioxane derivatives was investigated. Peculiar cases of prostereoisomerism and the NMR spectroscopic identification of pro-R, pro-S, pro-cis, and pro-trans groups are reported for these achiral flipping compounds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00013481
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  • 8
    Electronic Resource
    Electronic Resource
    Crystal and Molecular Structure of 2-Amino-5-butyl-3-ethyl-6-methyl-4(3H)-pyrimidinone (1998)
    Springer
    Monatshefte für Chemie 129 (1998), S. 735-740 
    Details
    ISSN: 1434-4475
    Keywords: Keywords. 2-Amino-4-pyrimidinone; Tautomerism; X-Ray crystal structure.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  Die Struktur von 2-Amino-5-n-butyl-3-ethyl-6-methyl-4(3H)-pyrimidinon (1) wurde roöntgenstrukturanalytisch und mittels ab intitio– Berechnungen (HF/6-31G*) untersucht. Die Roöntgenstrukturanalyse zeigt, daß1 als Amino-Oxo-Tautomer (AO) vorliegt, was mit den Ergbnissen der Rechnungen übereinstimmt. Die Kristalle von 1 sind tetragonal (Raumgruppe P42/n) mit den Zellparametern a=b=17.074 Å, c=8.809 Å und α=β=γ=90°. Der 4-Pyrimidinonring ist im Kristall planar; der Aminstickstoff und der Carbonylsauerstoff liegen in der Ringebene. Die Molekuüle der Verbindung 1 werden durch starke intermolekulare Wasserstoffbruücken verbunden, die von der NH2-Gruppe einer Einheit zur C*O-Gruppe der naächsten reichen (N–H⋯O – Abstand: 2.88 Å).
    Notes: Summary.  The structure of 2-amino-5-n-butyl-3-ethyl-6-methyl-4(3H)-pyrimidinone (1) has been studied by X-ray diffraction and ab initio calculations at the HF/6-31G* level. X-ray analysis established that 1 exists as the amino-oxo tautomer (AO) in the solid state, in good agreement with the ab initio results. Crystals of 1 are tetragonal (space group P42/n); the unit cell dimensions are a=17.074 Å, b=17.074 Å, c=8.809 Å, α=β=γ=90°. The 4-pyrimidinone ring is essentially planar in the crystal, the amino nitrogen and the carbonylic oxygen being located in the plane of the ring. The 2-amino-5-n-butyl-3-ethyl-6-methyl-4(3H)-pyrimidinone molecules are linked by strong N–H⋯O intermolecular hydrogen bonds from the NH2 group of one molecule to the C*O group of an adjacent molecule (N–H⋯O distance: 2.88 Å).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00013482
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  • 9
    Electronic Resource
    Electronic Resource
    Synthesis and Stereochemistry of Novel Dibrominated 1,5-Dioxaspiro[5.5]undecane Derivatives (2000)
    Springer
    Monatshefte für Chemie 131 (2000), S. 277-286 
    Details
    ISSN: 1434-4475
    Keywords: Keywords. Spiro compounds; Diastereoselective bromination; X-Ray structure determination; Conformation; NMR Spectroscopy.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary.  The synthesis and stereochemistry of new dibrominated spiro-1,3-dioxane derivatives are reported. Investigations by means of NMR methods and single crystal X-ray diffraction for two compounds revealed the high regio- and diastereoselectivity of the bromination reaction of some new spiro-1,3-dioxanes and the asymmetric induction of the chiral carbon atom located in the spiro skeleton.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s007060070103
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  • 10
    Electronic Resource
    Electronic Resource
    Synthesis and Stereochemistry of Some New Trispiro-1,3-dioxaneswith Axial and Helical Chirality (1998)
    Springer
    Monatshefte für Chemie 129 (1998), S. 59-68 
    Details
    ISSN: 1434-4475
    Keywords: Keywords. Trispiro-1 ; 3-dioxanes; Syn and anti structures; Conformational analysis; Axial and helical chirality; NMR studies.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung.  Die Stereoisomerie einiger aus substituierten Cyclohexanonen und Pentaerythritol hergestellter Trispiro-1,3-dioxane wird im Hinblick auf die möglichen Trispiro-6,9-syn-9-12-syn-, Trispiro-6,9-syn-9,12-anti- und Trispiro-6,9-anti-9,12-Strukturen des Spiranskeletts und die charakteristische axiale und helikale Chiralität von Spiranen mit sechsgliedrigen Ringen diskutiert. Der Einfluβ von chiralen Kohlenstoffatomen und des speziellen konformativen Verhaltens auf die Stereoisomerie dieser Verbindungen wird rationalisiert.
    Notes: Summary.  The stereoisomerism of some trispiro-1,3-dioxanes obtained from substituted cyclohexanones and pentaerithrytol is discussed considering the possible trispiro-6,9-syn-9,12-syn, trispiro-6,9-syn-9,12-anti, and trispiro-6,9-anti-9,12-anti structures of the spiro skeleton and the characteristic axial and helical chirality of spiranes with six-membered rings. The influence of the presence of chiral carbon atoms and of the peculiar conformational behaviour of the molecules on the stereoisomerism of the these compounds is elucidated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00010105
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