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  • 1
    Electronic Resource
    Electronic Resource
    Nitroxides (aminyl oxides). 39. Formation of polycyclic dimers from vinyl nitroxides and their dissociation and isomerization (1988)
    s.l. : American Chemical Society
    The @journal of organic chemistry 53 (1988), S. 4997-5004 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00256a017
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  • 2
    Electronic Resource
    Electronic Resource
    Aminyl oxides (nitroxides). 36. Formation of 3,7-dioxa-2,6-diazabicyclo[3.3.0]octanes by dimerization of vinyl aminyl oxides (vinyl nitroxides) (1984)
    s.l. : American Chemical Society
    The @journal of organic chemistry 49 (1984), S. 2654-2656 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00188a037
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  • 3
    Electronic Resource
    Electronic Resource
    Bicyclic and Tricyclic Compounds with β-Amino Alcohol Groups as Chiral Ligands in the Enantioselective Reaction of Diethylzinc with Aldehydes (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 423-434 
    Details
    ISSN: 0947-3440
    Keywords: 3,7-Dioxa-2-azabicyclo[3.3.0]octanes ; 2,6-Dioxa-3-azatricyclo[5.3.1.04.11]undecanes ; Amino alcohols ; Chiral ligands ; Enantioselective catalysis ; Homogenous catalysis ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reduction of the enantiomerically pure allyloxy esters 9 or ent-9 with DIBAH afforded the corresponding aldehydes which were treated in situ with chiral or achiral hydroxylamines 8 to give nitrones 10. These underwent a spontaneous intramolecular 1,3-dipolar cycloaddition, affording the bicyclic compounds 11 and 12, respectively. In an analogous manner, a mixture of the tricyclic compounds 14 and 15 was prepared. Treatment of compound 16 with cyclohexene oxide afforded a mixture of diastereomers 17 and 18. Diastereomers 14 and 15 as well as 17 and 18 could be separated by chromatography. X-ray analyses of compounds 11Ff, 17, and 11Af · HCl were performed. The bicyclic and tricyclic compounds were used as chiral ligands in the reaction of diethylzinc with aldehydes 19, in particular with benzaldehyde (19a). Using bicyclic compounds with a tertiary β-hydroxyalkyl substitutent at the N atom as ligands, ee's in the range of 78 to 95% were found. Whereas for the best ligands 11Ae and Af the enantioselectivity in the reaction of 4-tolualdehyde was only slightly decreased, with the aliphatic aldehydes 19c and d distinctly lower enantioselectivities were determined.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970222
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  • 4
    Electronic Resource
    Electronic Resource
    Nitroxide, V. Beziehungen zwischen den ESR-Kopplungskonstanten und der Konformation bei Azomethin-nitroxiden (1968)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 101 (1968), S. 1770-1782 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die ESR-Spektren der Azomethin-nitroxide 2-6 kann man durch Substitution der Phenylkerne mit tert.-Butylgruppen und gegebenenfalls mit Deuterium entscheidend vereinfachen, so daß eine vollständige Analyse möglich wird. Dabei ergibt sich für die Nitroxide 2 und 3 eine relativ große Spindichte an der Nitroxidgruppe und im benachbarten Phenylkern Ar2 und eine sehr geringe Spindichte am Azomethin-Stickstoff. Demgegenüber ist in den Nitroxiden 4-6 das ungepaarte Elektron in viel stärkerem Maße über das gesamte Molekül delokalisiert. Die Nitroxide 4-6, sollten daher nahezu eben gebaut sein, während in den Nitroxiden 2 und 3 die Molekülteile gegeneinander verdrillt sein müssen, was auf sterische Ursachen zurückgeführt wird.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19681010531
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  • 5
    Electronic Resource
    Electronic Resource
    Nitroxide, IVIII. Mitteil.: H. G. Aurich und F. Baer, Angew. Chem. 79, 1070 (1967); Angew. Chem. internat. Edit. 6, 1080 (1967); II. Mitteil.: l. c.. Die Darstellung von Azomethin-nitroxiden (1968)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 101 (1968), S. 1761-1769 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nach verschiedenen Verfahren werden C-Amino-nitrone 1 B (5, 15) bzw. deren Hydrochloride (9) dargestellt, die sich zu den Nitroxiden 2 (6, 16, 10) oxydieren lassen: α-Anilino-phenylacetonitril (3) ergibt mit Nitrosoverbindungen in Gegenwart von Basen die Amino-nitrone 5. Arylhydroxylamine reagieren mit N-Phenyl-trimethylacetimidchlorid (7) zu den Hydrochloriden 9. Die C-Amino-nitrone 15 werden entweder durch Umsetzung von N-Aryl-form-imidsäure-äthylestern (11) mit Arylhydroxylaminen bzw. tert.-Butylhydroxylamin oder von N-Methylen-aminen (13) mit aromatischen Nitrosoverbindungen gewonnen.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19681010530
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  • 6
    Electronic Resource
    Electronic Resource
    Aminyloxide, XII. Nachweis und Reaktionen des Benzotriazolyl-1-oxid-Radikals (1973)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 2408-2414 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aminyl Oxides, XII. Determination and Reactions of Benzotriazolyl 1-OxideOxidation of 1-hydroxybenzotriazole (4) in the absence of oxygen yields benzotriazolyl 1-oxide (5), whereas in the presence of oxygen benzotriazolyl 1,3-dioxide (6) is formed. The reaction of 5 with benzene, thiophene, dimethyl acetylenedicarboxylate or 2,4,6-trimethoxybenzonitrile oxide results in nitrogen evolution and the formation of the product radicals 9, 10, 11 and 8c, respectively.
    Notes: Durch Oxidation des 1-Hydroxybenzotriazols (4) erhält man unter Sauerstoffausschluß das Benzotriazolyl-1-oxid-Radikal (5), in Gegenwart von Sauerstoff das Benzotriazolyl-1,3-dioxid (6). 5 reagiert unter N2-Abspaltung mit Benzol und Thiophen zu den Sekundärradikalen 9 bzw. 10, mit Acetylendicarbonsäure-dimethylester zu 11 und mit 2,4,6-Trimethoxybenzonitriloxid zu 8c.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19731060738
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  • 7
    Electronic Resource
    Electronic Resource
    Aminyloxide, XVI. Über die Darstellung von Acyl-aminyloxiden und ihre Konformation (1973)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 3483-3494 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aminyl Oxides, XVI. Preparation of Acylaminyl Oxides and their Conformational BehaviourThe hydroxamic acids 5, obtained along with the O-acylhydroxylamines 6 upon acylation of N-tert-butylhydroxylamine, are oxidized to the open-chain acylaminyl oxides 1. The cyclic acylaminyl oxides 2 and 3 are prepared for purposes of comparison. The conformation of the radicals 1 and of some of the precursors 5 is studied by e.s.r. and i.r. spectroscopy using the corresponding cyclic compounds for comparison. The energy barrier for ring inversion in 3 is determined from temperature-dependent line broadening in the e.s.r. spectrum.
    Notes: Die bei der Acylierung von N-tert-Butylhydroxylamin neben den O-Acylhydroxylaminen 6 entstehenden Hydroxamsäuren 5 werden zu den offenkettigen Acyl-aminyloxiden 1 oxidiert. Zum Vergleich werden die cyclischen Acyl-aminyloxide 2 und 3 hergestellt. Die Konformation einiger Hydroxamsäuren 5 und der Radikale 1 wird unter Vergleich mit den entsprechenden cyclischen Verbindungen mittels IR- bzw. ESR-Messungen untersucht. Die Energiebarriere für die Ringinversion von 3 wird aus der Temperaturabhängigkeit der Linienverbreiterung des ESR-Spektrums bestimmt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19731061104
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  • 8
    Electronic Resource
    Electronic Resource
    Aminyloxide (Nitroxide), XXXV. Das tricyclische Dimere eines Vinylaminyloxids (Vinylnitroxids) und seine Isomerisierung zu einem 2,4,7,9-Tetraoxa-5,10-diazatetracyclo[4.4.2.03,12. 08,11]dodecan (1984)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 117 (1984), S. 2615-2621 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aminyl Oxides (Nitroxides), XXXV. The Tricyclic Dimer of a Vinyl Aminyl Oxide (Vinyl Nitroxide) and its Isomerization to give a 2,4,7,9-Tetraoxa-5,10-diazatetracyclo[4.4.2.03,12.08,11]dodecaneVinyl aminyl oxide 6 is formed by oxidation of hydroxylamine 3 via the intermediates 4 and 5. Dimerization of 6 yields the tricyclic compound 8. In solution dissoziation of 8 occurs at approximately 40°C, four bonds being cleaved to afford radical 6. By prolonged heating in various solvents as well as by proton catalysis at room temperature 8 is rearranged to give the tetracyclic isomer 9, the structure of which has been confirmed by X-ray analysis.
    Notes: Das Vinylaminyloxid 6 entsteht bei der Oxidation des Hydroxylamins 3 über die Zwischenstufen 4 und 5. 6 dimerisiert unter Bildung der tricyclischen Verbindung 8. 8 dissoziiert in Lösung bereits bei etwa 40°C unter Spaltung von vier Bindungen in das Radikal 6. Durch längeres Erhitzen in verschiedenen Lösungsmitteln, aber auch unter Protonenkatalyse bei Raumtemperatur, wird 8 in ein tetracyclisches Isomeres 9 umgewandelt. Die Struktur von 9 wurde durch Röntgenstrukturanalyse ermittelt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19841170806
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  • 9
    Electronic Resource
    Electronic Resource
    Nitroxide, XI. Darstellung und Umwandlung von 3-Oxo-3H-indolyl-(2)-nitroxiden (1972)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 105 (1972), S. 2389-2397 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Nitroxides, XI. Preparation and Reactions of 3-Oxo-3H-2-indolylnitroxidesThe 3-oxo-3 H-2-indolylnitroxides 8 and 9 are prepared by oxidation of the nitrones 6 and 7. Hydroxide ions convert the radicals 8 into the nitroxides 13. 13a was synthesized independently. Ring opening of 13 by attack of certain nucleophiles leads to the formation of the carbamoylnitroxides 17-21.
    Notes: Durch Oxydation der Nitrone 6 und 7 wurden die 3-Oxo-3 H-indolyl-(2)-nitroxide 8 und 9 dargestellt. Die Radikale 8 lassen sich mit Hydroxid-Ionen in die Nitroxide 13 umwandeln. 13a konnte auf unabhängigem Wege synthetisiert werden. Mit verschiedenen Nucleophilen tritt eine Ringöffnung von 13 ein, die zu den Carbamoyl-nitroxiden 17-21 führt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19721050732
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  • 10
    Electronic Resource
    Electronic Resource
    Sterisch bedingte Umwandlung von N-Hydroxyharnstoffen und N-Hydroxyguanidinen (1973)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 106 (1973), S. 1881-1896 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sterically Induced Transformation of N-Hydroxyureas and N-HydroxyguanidinesIn solution N-hydroxyureas 13 (R1-tert-alkyl) rearrange to O-carbamoylhydroxylamines 14. A combination of IR-spectroscopic results, trapping reactions and cross experiments shows that the reaction proceeds via sterically induced dissociation of 13 into isocyanates and hydroxylamines.  -  In solution the N-hydroxyguanidines 22 (R1 - tert- or sec-alkyl) decompose into ureas 23-25, guanidines 26, nitroso derivatives 27-29 or the corresponding oximes. The mechanism of the transformation was studied using 22a as the model compound. The reaction is initiated by decomposition into 1 and 19. 1 is partly oxidized to 27. 19 adds to 22a to give 31a which leads to the decomposition products. The product of rearrangement 30a is also formed.
    Notes: N-Hydroxyharnstoffe 13 (R1 = tert-Alkyl) lagern sich in Lösung in die O-Carbamoyl-hydroxylamine 14 um. Die Reaktion verläuft über eine sterisch bedingte Dissoziation von 13 in Isocyanate und Hydroxylamine, wie durch IR-spektroskopische Befunde, Abfangreaktionen und Kreuzungsexperimente gezeigt wurde. N-Hydroxyguanidine 22 (R1  -  tert- oder sek-Alkyl) zerfallen in Lösung in Harnstoffe 23--25, Guanidine 26 und Nitrosoverbindungen 27-29, bzw. die entspreehenden Oxime. Der Mechanismus der Umwandlung wurde am Beispiel 22a untersucht. Die Reaktion wird durch einen partiellen Zerfall in 1 und in 19 eingeleitet. 1 wird teilweise zu 27 oxidiert, 19 ergibt mit 22a das Additionsprodukt 31a, von dem sich die weiteren Zerfallsprodukte ableiten lassen. Außerdem entsteht das Umlagerungs-produkt 30a.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19731060618
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