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  • 1
    Series available for loan
    Series available for loan
    Paläogeographischer Atlas des süddeutschen Oberjura (Malm) (1989)
    Hannover : Scweizerbart
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    Call number: SR 90.0066(115)
    In: Geologisches Jahrbuch
    Type of Medium: Series available for loan
    Pages: 77 S. + 10 Kt. Beil.
    Series Statement: Geologisches Jahrbuch : Reihe A 115
    Language: German
    Location: Lower compact magazine
    Branch Library: GFZ Library
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  • 2
    Electronic Resource
    Electronic Resource
    Coupled torsional and bending motions in s-cis methyl vinyl ether (1987)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 86 (1987), S. 1848-1857 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: New microwave measurements on s-cis methyl vinyl ether and a study of the interactions among skeletal and methyl torsions and COC bending are reported. Using pulsed microwave Fourier transform spectroscopy, the small methyl torsional A–E splitting (0.16 MHz) in the vibrational ground state has been resolved for the first time. Large splittings are observed in the first excited states of skeletal torsion and COC bending. Ab initio results on the torsional coupling, allowing for structural relaxation, are reported and used to specify, in part, a flexible model for the torsional and bending motions. The spectroscopic properties of this three-dimensional model sytem, as estimated from the results for the one-dimensional and two-dimensional subsystems, explain the relevant experimental data. The gearing type torsional interaction predicted ab initio is confirmed by this treatment. The adjusted potential function as well as the structural relaxations upon torsion suggest repulsive interaction between the methyl hydrogen atoms and the methylenic hydrogen atom next to the methyl group.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.452741
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  • 3
    Electronic Resource
    Electronic Resource
    Pseudorotation pathway and equilibrium structure from the rotational spectrum of jet-cooled tetrahydrofuran (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 111 (1999), S. 7871-7880 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The rotational spectrum of jet-cooled tetrahydrofuran has been investigated in the 8–18 and 60–78 GHz frequency ranges. Only the four lowest vibrational levels remain populated in the jet conditions. Two pseudorotation vibrational spacings have been measured directly to be ΔE01=21 307.71(3) MHz and ΔE23=61 205.69(3) MHz. They have been used, together with the lowest 10 measured far infrared transition frequencies and with the effective moments of inertia of the ground state and their shifts upon excitation observed in this work, to determine the potential energy function for pseudorotation and the associated structural relaxations. The potential energy barriers are 45 cm−1 at the envelope conformation of the oxygen and 16 cm−1 at the twisted conformation of the Cβ–Cβ′ bond relative to the CαOCα′ plane. The four symmetrically equivalent equilibrium structures are close to the envelope conformations of the CH2 groups next to the oxygen atom. While the C–O bond lengths and the local CH2 angles appeared to remain unaffected by pseudorotation, significant changes found for the diagonal O(centered ellipsis)C distances as well as for the C–C and C–H bond lengths are of interest as possible effects of hyperconjugation. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.480122
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  • 4
    Electronic Resource
    Electronic Resource
    Microwave investigation of lactonitrile. Potential functions to the hydroxyl and methyl group torsions (1985)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 83 (1985), S. 3729-3737 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The rotational spectrum of lactonitrile, CH3CH(OH)CN, has been reinvestigated. The analysis has been extended to the CH3CH(OD)CN species and to several excited states of the hydroxyl and methyl internal rotations. The molecule exhibits two conformers with the hydroxyl hydrogen gauche with respect to the cyano group. The conformer A with the hydroxyl hydrogen adjacent to the methinic hydrogen is 118±30 cm−1 (75±30 cm−1 for the OD species) more stable than the conformer B with the hydroxyl hydrogen adjacent to the methyl group. The barrier height to the interconversion is about 400 cm−1. Rotational A–E splittings due to methyl internal rotation have been observed in the first excited state of both conformers, yielding effective V3 barriers of 3.7 kcal/mol for conformer A and 4.3 kcal/mol for conformer B. By using a one-dimensional flexible model treatment the potential function and the structural relaxation associated with the OH torsion have been determined from the level spacings and the variations of the rotational constants, upon excitation. The potential profile and the structural relaxation indicate a repulsion of the hydroxyl hydrogen atom by the methyl group and an attraction by the cyano group. A preliminary two-dimensional model including both torsions is applied to the parent species. A comparison of the respective results with observations suggests some potential energy coupling of the two torsions and/or structural relaxation associated also with methyl internal rotation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.449134
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  • 5
    Electronic Resource
    Electronic Resource
    N-Acyldehydro-α-aminosäuren aus N-Formyldehydro-α-amino-säure-methylestern (1981)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1981 (1981), S. 1469-1475 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: N-Acyl Dehydro-α-amino Acids from N-Formyl Dehydro-α-amino Acid EstersOn treatment with methyl potassioisocyanoacetate (2), aldehydes and ketones 1 give N-anionized N-formyl dehydro-α-amino acid methyl esters 3. Compound 3 with R1 = CH3, R2 = H is obtained by base induced ring opening of methyl 2-oxazoline-4-carboxylate 5.  -  Acylation of 3, followed by deformylation of the intermediates 6, yields N-acyl dehydro-α-amino acid methyl esters 7 which can be hydrolyzed to the N-acyl dehydro-α-amino acids 8.
    Notes: Aus Aldehyden und Ketonen 1 erhält man mit Kalioisocyanessigsäure-methylester (2) durch Formylaminomethylenierung die am Stickstoff anionisierten N-Formyldehydro-α-aminosäure-methylester 3. Für 3 mit R1 = CH3 und R2 = H ist die baseninduzierte Ringöffnung des 2-Oxazolin-4-carbonsäure-methylesters 5 günstiger.  -  Durch N-Acylierung von 3, gefolgt von Entformylierung der Zwischenstufen 6, erhält man die N-Acyldehydro-α-aminosäureester 7, die zu den N-Acyldehydro-α-aminosäuren 8 hydrolysierbar sind.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198119810818
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  • 6
    Electronic Resource
    Electronic Resource
    Metallsubstituierte Carbene und C-metallierte Diazoalkane, VI1) α-Diazo-β-hydroxy-carbonsäureester und -ketone aus Carbonyl- und Diazolithioverbindungen sowie ihre Umlagerung zu β-Ketocarbonsäureestern und β-Diketonen (1974)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1974 (1974), S. 1767-1783 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal-substituted Carbenes and C-metalated Diazoalkanes, VI1). - α-Diazo-β-hydroxy-carboxylates and -ketones from Carbonyl and Diazo Lithio Compounds and their Rearrangement into β-Ketocarboxylates and β-DiketonesEthyl diazoacetate (1a) can be metalated with butyllithium in tetrahydrofuran at -65°C to -110°C to give ethyl diazolithioacetate (2a), which reacts with the carbonyl compounds 3 to give (after hydrolysis) the α-diazo-β-hydroxycarboxylates 4. These can also be obtained more conveniently, by in situ reaction of 1a and 3 with butyllithium (-65°C, tetrahydrofuran). On treatment with hydrogen chloride the compounds 4 rearrange (with loss of nitrogen) to the β-ketocarboxylates 19. In the case of cycloalkanones this sequence represents a ring enlargement. - The α-diazo-β-hydroxyketones 5-8 are formed when a mixture of the carbonyl compounds 3 and the diazoketones 1b-e is treated (in tetrahydrofuran, -65°C) with lithium diisopropylamide. Butyllithium is not suitable as metalating reagent. As in the case of compounds 5, on treatment with acids α-diazo-β-hydroxyketones suffer partial rearrangement to β-diketones (with loss of nitrogen) and partial retro-aldol reaction to 3 and diazoketones.
    Notes: Diazoessigsäure-äthylester (1a) ist mit Butyllithium bei - 65 bis - 110°C (in Tetrahydrofuran) in Diazolithioessigsäure-äthylester (2a) umwandelbar, welcher mit den Carbonylverbindungen 3 die α-Diazo-β-hydroxycarbonsäureester 4 liefert. Diese sind auch in situ aus 1 a und 3 mit Butyllithium zugänglich. Sie lassen sich protonenkatalysiert in die β-Ketocarbonsäureester 19 umlagern. Bei Cycloalkanonen entspricht dies einer Ringerweiterung. - Aus den Diazoketonen 1b-e erhält man die α-Diazo-β-hydroxyketone 5-8, indem man sie bei ca. -70°C im Gemisch mit den Carbonylverbindungen 3 mit Lithiumdiisopropylamid umsetzt. Butyllithium ist hier als Metallierungsmittel ungeeignet. Wie sich mit den Verbindungen 5 ergab, werden α-Diazo-β-hydroxyketone protonenkatalysiert in unterschiedlichem Ausmaß zu ß-Diketonen umgelagert oder in einer Retroaldolreaktion zu Carbonylverbindungen 3 und Diazoketonen gespalten.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197419741106
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesen mit α-metallierten Isocyaniden, XXXVIII. Trialkylmethyl-substituierte Glycine und Pyrrol-2,4-dicarbonsäureester aus 2-Isocyanacrylsäureestern und Carbanionen (1977)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1977 (1977), S. 1174-1182 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with 2-Metalated Isocyanides, XXXVIII. - Trialkylmethyl Substituted Glycines and Pyrrole-2,4-dicarboxylic Esters from 2-Isocyanoacrylic Esters and CarbanionsThe following Michael additions of carbanions to 2-isocyanoacrylic esters 2 are described: 1. The addition of Grignard compounds 4 to give 2-isocyano-2-(trialkylmethyl)ethanecarboxylic esters 5 which on hydrolysis form trialkylmethyl-substituted glycines (type 6 or 7); 2. the addition of ethyl lithioisocyanoacetate (8) to give 3-substituted diethyl pyrrole-2,4-dicarboxylates 11; and 3. the addition of diethyl sodiomalonate to form triethyl 1-isocyano-2,2-dimethylpropane-1,3,3-tricarboxylate (14).
    Notes: Folgende Michael-Additionen von Carbanionen an 2-Isocyanacrylsäureester 2 werden beschrieben: 1. die Addition von Grignard-Verbindungen 4 zu 2-Isocyan-2-(trialkylmethyl)-ethansäureestern 5, welche zu Trialkylmethyl-substituierten Glycinen (Typ 6 oder 7) hydrolysierbar sind, 2. die Addition von Lithioisocyanessigsäure-ethylester (8), die im Endeffekt 3-substituierte Pyrrol-2,4-dicarbonsäurediester 11 liefert und 3. die Addition von Natrium-malonsäureester an 2a, welche zu 1-Isocyan-2,2-dimethylpropan-1,3,3-tricarbonsäure-triethylester (14) führt.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197719770714
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  • 8
    Electronic Resource
    Electronic Resource
    Synthesen mit α-metallierten Isocyaniden, XXXIX. 2-Imidazoline aus α-metallierten Isocyaniden und Schiff-Basen; 1,2-Diamine und 2,3-Diaminoalkansäuren (1977)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1977 (1977), S. 1183-1193 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses with α-Metalated Isocyanides, XXXIX - 2-Imidazolines from α-Metalated Isocyanides and Schiff Bases; 1,2-Diamines and 1,2-Diaminoalkanoic acidsα-Metalated isocyanides 1 react with Schiff bases 5 to give via the intermediates 6 and 7 2-unsubstituted 2-imidazolines 8. The intermediate 2-metalated 2-imidazolines 7 can be trapped with electrophiles to give 2-substituted 2-imidazolines (for instance 9). - Alkyl 2-imidazoline-4-carboxylates 8f-o can be obtained alternatively from alkyl 2-isocyanoacrylates 11a,b and primary amines or ammonia. - On acides hydrolysis 2-imidazolines 8 give 1,2-diamines 13 or 2,3-diaminoalkanoic acids 14.
    Notes: α-Metallierte Isocyanide 1 reagieren mit Schiff-Basen 5 über die Zwischenstufen 6 und 7 zu 2-unsubstituierten 2-Imidazolinen 8. Die 2-metallierten Imidazoline vom Typ 7 können mit Elektrophilen zu 2-substituierten 2-Imidazolinen (z. B. 9) umgesetzt werden. - 2-Imidazolin-4-carbonsäureester 8f-o erhält man alternativ aus 2-Isocyanacrylsäureestern 11a,b und primären Aminen oder Ammoniak. - Die 2-Imidazoline 8 liefern bei der Hydrolyse 1,2-Diamine 13 oder 2,3-Diaminoalkansäuren 14.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197719770715
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  • 9
    Electronic Resource
    Electronic Resource
    Totalsynthese von (±)-2,2-Diethyl-3-methyl- und (±)-2,2-Diethyl-3,6-dimethyl-6-(phenoxyacetamido)penam-3-carbonsäure (1978)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1978 (1978), S. 1982-1989 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of (±)-2,2-Diethyl-3-methyl- and (±)-2,2-Diethyl-3,6-dimethyl-6-(phenoxyacetamido)-penam-3-carboxylic acidThe title compounds 4I and 4k were synthesized as the potassium salts 4I', 4k' starting from benzyl 4-methyl-2-thiazolinecarboxylate (3a).  -  The preparation of several benzyl 2-thiazoline-4-carboxylates (type 3) from thioketones 2 and 2-metalated benzyl 2-isocyanoalkanecarboxylates 1b, d is described.
    Notes: Die im Titel genannten Verbindungen 4I und 4k wurden (als Kaliumsalze 4I' bzw. 4k') ausgehend von 5,5-Diethyl-4-methyl-2-thiazolin-4-carbonsäure-benzylester (3a) dargestellt.  -  An mehreren Beispielen wird die Synthese von 2-Thiazolin-4-carbonsäure-benzylestern (Typ 3) aus Thioketonen 2 und 2-metallierten 2-Isocyanalkansäureestern 1b und d beschrieben.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197819781213
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  • 10
    Electronic Resource
    Electronic Resource
    Synthese von tert.-alkyl-substituierten Glycinen (1975)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 87 (1975), S. 624-625 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19750871705
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