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  • 1
    Electronic Resource
    Electronic Resource
    Determination of urinary oxalate and porphyrins by peroxyoxalate chemiluminescence
    Amsterdam : Elsevier
    Analytica Chimica Acta 255 (1991), S. 413-416 
    Details
    ISSN: 0003-2670
    Keywords: Chemiluminescene ; Oxalate ; Porphyrins ; Urine
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0003-2670(91)80076-6
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  • 2
    Electronic Resource
    Electronic Resource
    Imidazolidinderivate aus OxalamidinenHerrn Prof. Dr. Dr. h. c. H. G. O. Becker zum 60. Geburtstag gewidmet (1982)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 324 (1982), S. 227-236 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Derivatives of Imidazolidines from Oxalic AmidinesTetraarylsubstituted oxalic amidines 1 react with acyl chlorides, phosgene, thiophosgene, chlorocarbonylsulfenylchloride, isocyaniddichlorides, and N-aroyl-1-chlorothio-formimidoylchlorides 7 to give the corresponding 5-membered heterocycles 3, 4, 5 and 8.Isocyanates 9 and isothiocyanates 10 react with oxalic amidines to yield imidazolidines 11, 12 and ureas 13, 14.Hydrolysis of 3-5, 8, 11, 12 leads to the corresponding oxo compounds 15, 16.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19823240207
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  • 3
    Electronic Resource
    Electronic Resource
    Zur Reaktion der N-Sulfinylamine mit Isocyaniden und die Synthese von 2,5-Diaryl-3,4-diarylimino-1,2,5-thiadiazolidin-S-oxiden (1980)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 322 (1980), S. 273-280 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Reaction of N-Sulfinylamines with Isocyanides and Synthesis of 2,5-Diaryl-3,4-diarylimino-1,2,5-thiadiazolidin-S-oxidesN-Sulfinylamines 1 react with isocyanides 2 to give isocyanates 3, isothiocyanates 6, and especially 2,5-diaryl-3,4-diarylimino-1,2,5-thiadiazolidin-S-oxides 7.This new heterocyclic ring system 7 can also be synthesized in high yields by a cyclization reaction of tetraarylated oxalic amidines 9 with thionyl chloride.The acid catalyzed hydrolysis of the heterocyclic compounds 7 leads to oxalic anilides 8, the hydrolysis with alkali forms amidines 9. The amidine 9a reacts with N-sulfinyl-p-toluenesulfonamide 11 to give an open chained adduct 12.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19803220213
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  • 4
    Electronic Resource
    Electronic Resource
    MO-LCAO-Berechnungen an schwefelhaltigen π-Elektronensystemen. XLIX. Tetramethinverbrückte Oxalsäurederivate - neue farbige Pigmente von indigoider StrukturProf. Dr. habil. R. Mayer zum 60. Geburtstag gewidmet (1986)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 328 (1986), S. 805-811 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: MO-LCAO Calculations on Sulfur-containing π-Electron Systems. XLIX. Tetramethine Bridged Derivatives of the Oxalic Acid - Novel Coloured Pigments of Indigoid StructureWhereas thioamides react with the oxalylchloride to Δ2-thiazoline-4,5-diones 1, which are precursors of the versatile thioacylisocyanate 2 synthons, the analogous reaction between thioamides and oxalyl-bis(arylimidchlorides) completely fails. In the case of aliphatic thioamides the intermediate 2-methyl-Δ2-thiazoline-4,5-diimides 3 undergo oxydative dimerization. The poorly soluble products are tetramethine bridged heteroanalogous oxalates 4 or isomers. The u.v./vis spectra of the blue compounds are in favour with structure 4 rather than with structure 6. This conclusion has been drawn from the results of Pariser-Parr-Pople(PPP) type calculations. According to the calculated position of the colour band of the pigments and of different molecular subunits, and the correspondence of their electronic states involved in the excitation, the dye molecules can be thought as consisting of two symmetrically crossed polymethine chains. This structural feature is inherent to the H indigo chromophore.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19863280520
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  • 5
    Electronic Resource
    Electronic Resource
    Zur negativen Solvatochromie von Cyclohexa-2,5-dien-1-thion-Derivaten (1993)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 335 (1993), S. 95-97 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Negative Solvatochromism of Cyclohexa-2,5-diene-1-thion Derivatives
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19933350115
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  • 6
    Electronic Resource
    Electronic Resource
    1,3-Acylumlagerungen bei der Cyclisierung von Thioharnstoffen mit Imidoylchloriden der Oxalsäure - Ein Zugang zu interessanten ThiocarbonylsystemenHerrn Prof. Dr. habil. R. Mayer zum 65. Geburtstag gewidmet (1992)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 334 (1992), S. 611-618 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,3-Acylrearrangements by Cyclisation of Thioureas with Imidochlorides of Oxalic Acid - An Approach to interesting Thiocarbonylic SystemsBy cycloacylation of various substituted thioureas with bis-imidochlorides of oxalic acid the new thiazolidines 3, 4 and isomeric imidazolidines 5, 6 are obtained. Especially when triethylamine is used as a base the main products are the deeply coloured 4-arylimino-5-thioxo-imidazolidines which can be regarded as s-cis-configurated 1,4-dihetero-1,3-dienes. Some thiazolidines can be rearranged by means of anhydrous organic acids to parabanic acid derivatives; whereas the 5-thioxo-imidazolidines result from an intramolecular 1,3-acyl rearrangement during the reaction.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19923340711
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  • 7
    Electronic Resource
    Electronic Resource
    Tieffarbige Systeme mit Oxalsäurestruktur  -  eine Strukturkorrektur (1991)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 333 (1991), S. 555-559 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Deep Coloured Systems with Oxalic Acid Substructure-a Structural CorrectionBasing on a recent spectroscopic investigation the structure of earlier described deeply coloured systems derived from oxalic acid imidochlorides and thioacetamide has to be revised. Due to the poor solubility of these systems their spectroscopic characterization led to the misinterpretation as tetramethin-bridged thiazolines 1. By means of 1H-NOE-Difference-Spectroscopy of newly synthesized derivatives with lipophilic substituents a imidazolin-thion substructure 4 has been found. Such an arrangement of the heteroatoms clearly reflects a 1,3-rearrangement with participation of the oxalic acid system.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19913330406
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  • 8
    Electronic Resource
    Electronic Resource
    Neuartige Steroidale Orthoester durch intramolekulare Cyclisierung von Ethinylcarbinol-Derivaten mittels OrganylhypoioditenProf. Dr. habil. K. Ponsold zum 65. Geburtstag gewidmet (1991)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 333 (1991), S. 855-862 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Novel Steroidal Orthoesters by Intramolecular Cyclisation of Ethynylcarbinol Derivatives with Organic HypoioditesThe iodination of the 17β-acetoxy-17-ethynylsteroid 2 using iodine/copper(II)-acetate in combination with the nucleophiles acetic acid, water and methanol is reported. Examples for chemical modification of the products are described. A cyclisation occurs in the case of iodomethoxylation as a formal through-space 1.4-addition of the reagent forming a mixture of 4 isomer iodomethylen-1,3-dioxolanes. The configuration and ratio of the isomers as well as analytical data of this hitherto unknown dioxolane-system are given.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19913330607
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  • 9
    Electronic Resource
    Electronic Resource
    Zur Umsetzung von Oxalamidinen mit Heterocumulenen der Kohlensäurereihe zu Imidazolidin-Derivaten (1990)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 332 (1990), S. 65-82 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Reaction of Oxalic Amidines with Carbonic Acid Derived Heterocumulenes to Imidazolidine-DerivativesA useful synthetic route to nonsymmetric derivatives of imidazolidine (derivatives of parabanic acid) is demonstrated by the reaction of tetraarylated oxalic amidines 1 with different alkyl- and aryl substituted isothiocyanates 4, isoselenocyanates 31, and carbodiimides 30.Acylisothiocyanates 9 react differently leading to a mixture of three cycloacylation products 12, 13 and 14. Silylated heterocumulenes such as 25 and 26 react with 1 to give 28 and 29 transsilylation. Based on the 13C-n.m.r. spectroscopic investigation of the reaction between 1a and methyl isothiocyanate and phenyl isothiocyanate respectively a mechanism is proposed.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19903320108
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  • 10
    Electronic Resource
    Electronic Resource
    Untersuchungen zur Regioselektivität von Wittig-Horner- und Reformatsky-Reaktionen an ausgewählten 3,17-Dioxosteroiden (1990)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 332 (1990), S. 367-374 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Investigations on Regioselectivity of Wittig-Horner and Reformatsky-Reactions on Selected 3,17-Dioxo SteroidsThe Reformatsky synthesis and the Wittig-Horner olefination of 3,17-dioxo steroids like androsta-1,4-diene-3,17-dione (ADD) 1 and androst-4-ene-3,17-dione (AD) 2 is described. There are differences in the regioselective introduction of identical substructures with these two methods resulting from different nucleophilicity and stereoelectronical relations of these two reagents. In Reformatsky synthesis the oxo group in 3-position predominantly reacts, whereas in the Wittig-Horner olefination (in the case of 1) the reaction occurs mainly in the 17-position.The structures of all new compounds has been confirmed by spectroscopical data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19903320314
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