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  • 1
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The [2 + 2] Photocycloaddition of 2-(trimethylsilyloxy)-1,3-butadiene to a number of 2-cycloalkenones proved to be quite a general reaction leading to good yields of the cycloadducts (Table). This finding is surprising since dienes, in general, are better known as quenchers of enone triplets rather than as photochemical reactants. Both the high substrate concentrations, which can be employed in these cycloadditions, and the remarkable regio and stereoselectivity of the processes qualify them as valuable for syntheses. In a first application, the photoproducts 1a, b were transformed in three steps into a viable precursor 4 of the pentalenolactone-G and -H antibiotics.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Eine einfache Synthese von substituierten Perhydro-1,3-thiazin-4-onen und 2-Thioxoperhydro-4-pyrimidinonenDie basisch katalysierte Cyclisierung der N-Propenoylthioharnstoffe 3 liefert je nach den Reaktionsbedingungen entweder 2,6-disubstituierte 2,3,5,6-Tetrahydro-4H-1,3-thiazin-4-one 4 oder 1,6-disubstituierte 2-Thiouracile 5. Unter denselben Reaktionsbedingungen können die Verbindungen 5 durch eine Art Dimroth-Umlagerung aus den 1,3-Thiazin-4-onen 4 erhalten werden.
    Notes: Depending on the reaction conditions either 2,6-disubstituted 2,3,5,6-tetrahydro-4H-1,3-thiazin-4-ones 4 or 1,6-disubstituted 2-thiouracils 5 are readily prepared by base-catalyzed cyclization of N-propenoylthioureas 3. Compounds 5 could also be obtained by Dimroth-type rearrangement of 1,3-thiazin-4-ones 4 under the same reaction conditions.
    Additional Material: 2 Tab.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1990 (1990), S. 293-296 
    ISSN: 0170-2041
    Keywords: Pyridazine, derivatives ; Pyrazolo-pyridazine, derivative ; Pyrido-pyridazine, derivative ; Isoxazolo-pyridazine, derivative ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The pyridazines 3, 4, 5, and 7 were obtained by reaction of the hydrazone derivatives 2 with several reagents. By treatment of 5 with acetic acid/hydrochloric acid, the pyrazolo[4,3-c]-pyridazine 6 was formed. The pyrido-pyridazine derivatives 8 and 9 were obtained by reaction of 2 and 3 with malononitrile and ethyl cyanoacetate, respectively, and the isoxazolo-pyridazines 11 by reaction of 3a, b with hydroxylamine hydrochloride in ethanolic sodium ethoxide solution. The intermediate 9 was separated by reaction of 3a, b with hydroxylamine hydrochloride in ethanolic sodium acetate solution.
    Additional Material: 2 Tab.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1990 (1990), S. 461-464 
    ISSN: 0170-2041
    Keywords: Antitumor agents ; Oxaziridines ; Aldimines, unsaturated ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A convenient method for the synthesis of previously unknown oxaziridines having unsaturated substituents at the 3-position (3a-k) is based on the selective oxidation of the imino group of α,β-unsaturated aldimines 2 with m-chloroperbenzoic acid. The title compounds and 2-tert-butyl-3-(phenylethynyl)oxaziridine (3k) exhibit potent activity against experimental tumor cells in vitro.
    Additional Material: 4 Tab.
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 14 (1979), S. 961-986 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: An updated Lagrangian and a total Lagrangian formulation of a three-dimensional beam element are presented for large displacement and large rotation analysis. It is shown that the two formulations yield identical element stiffness matrices and nodal point force vectors, and that the updated Lagragian formulation is computationally more effective. This formulation has been implemented and the resulted of some sample analyses are given.
    Additional Material: 10 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 54 (1971), S. 117-135 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The influence of the presence of trimethylsilyl and triphenylsilyl groups in substituents of anthraquinone on the properties of anthraquinone vat, acid, and dispersion dyes was investigated.
    Additional Material: 6 Tab.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 332 (1990), S. 1041-1048 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1-Hydrazino-4-benzylphthalazine 1 underwent closure and/or condensation reaction with formic acid, acetic acid, acetic anhydride, trifluoroacetic anhydride, ortho esteres, aldehydes, urea or carbon disulphide to afford the N-formyl 3a, N-acyl 3b, and the appropriate 3-substituted-6-benzyl-s-triazolo [3,4-a] phthalazines 4a, c, 7, 8. Alkylation of the obtained s-triazolo[3,4-a]-phthalazine-3-thione 7 and s-triazolo [3,4-a] phthalazin-3-one 8 with N-substituted chloroacetamides gave the thioether 9 and N-substitution products 10, respectively. Likewise, applying Mannich conditions of the previously mentioned intermediates 7 and 8 yielded the N-Mannich bases (11 and 12). The new products were characterized by their elemental and spectral data.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 313 (1971), S. 594-601 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 4-Arylidene-2-phenyl-2-imidazolin-5-ones 1 react with Grignard reagents in a boiling ether-benzene mixture to yield 4-diarylmethyl derivatives 2 together with their oxidation products 3 and 4. The exocyclic double bond in 5 also undergoes addition reaction with the same reagents to yield 4-triarylmethyl derivatives 6. Alkylation of 2 affords the 4-alkylimidazolones 7 and 8.
    Additional Material: 3 Tab.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    International Journal for Numerical and Analytical Methods in Geomechanics 16 (1992), S. 779-796 
    ISSN: 0363-9061
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences
    Notes: A return mapping algorithm based on the concept of virtual surfaces is presented for stress integration in the numerical solution of boundary value problems using an elastoplastic multiple yield surface model. Both kinematic hardening and isotropic softening yield surfaces are addressed. With the implementation of virtual surfaces, the active yield surface is located before a stress update is implemented. The return mapping algorithm consists of only two steps. The first step consists of performing the intermediate update of the trial stress corresponding to the translation of all yield surfaces inside the active yield surface. Little calculation is involved in this step. The second step consists of performing the conventional explicit one-step radial return mapping of the updated trial stress on the corresponding active yield surface. The algorithm efficiency resides in the virtual surface based return mapping which preserves the elastic predictor representation of the updated trial stress, and limits iterations to at most two steps.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Communications in Applied Numerical Methods 7 (1991), S. 479-485 
    ISSN: 0748-8025
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: We present here a method of constructing a triangle interpolant which interpolates position and partial derivatives specified at the three vertices of the triangle. The method employs the cubic Bézier triangular patch technique. The data given enable us to determine the appropriate Bézier control points so that adjacent patches meet with C1 continuity. However, the interior control point for the patch is replaced by three separate points, due to the implementation of three local schemes, each of which satisfies the boundary conditions on only one side of the triangle. Convex combination is used to blend these three local schemes.
    Additional Material: 3 Ill.
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