ISSN:
0009-2940
Keywords:
Nitroxides, dimerization of / Vinyl nitroxides / 1,2-Oxazepines, 2,5,6,7-tetrahydro- / Nitrones
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Nitroxides (Aminyl Oxides), 43. - The Effect of Structural Features upon the Dimerization of Vinyl Nitroxides Substituted in β-Position by Cyclic Acyl GroupsReaction between N-alkyl- and N-arylhydroxylamines and hydroxymethylene compounds 4 (derivatives of menthone, norboranone, borananone, indanone, and γ-butyrolactone) affords nitrones existing in the tautomeric forms 5 and 6. Oxidation of these nitrones generates the β-acylated vinyl nitroxides 7, which dimerize in various ways. The N-alkyl-substituted vinyl nitroxides 7DA, De, Ea, Ga, and Gf yield simple CC-bonded dimers 8 From 7Ba dimer 10 is formed via 8Ba. The structure of 10 is confirmed by an X-ray analysis. In contrast, the N-arylsubstituted vinyl nitroxides 7 Ab, Fc, and Bc as well as the N-alkyl-substituted 7 Aa afford the bicyclic dimers 9 which arise by OC dimerization followed by an intramolecular 1,3-dipolar cycloaddition. Finally, the vinyl nitroxides 7Dc and Dd underwent further oxidation to give dehydrodimers 12. 12e is formed only if 6De is oxidized by a large excess of lead dioxide.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19901230318
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