876149-81-4Relevant articles and documents
Hydroxylamine function as neighboring group with dehydrogenations
M?hrle, Hans,Arndt, Petra
, p. 688 - 700 (2007/10/03)
The β-amino-hydroxylamines 5a-d are prepared of the α-amino-oximes 1a-d with borane-dimethylsulfide. With mercury-EDTA, 5a-d react to (E/Z)-oxime-lactams 3a-d and benzaldoxime 7. Additionally 5b,c give the bicyclic amidine-N-oxides 8b,c, which slowly hydrolyze to the hydroxylamine-lactams 9b,c. These are easily oxidized to (E/Z)-3b,c. Postulated as intermediates in the mercury-assisted reduction of 5, the cyclic hydroxylamines 10a-d are available from the nitrones 4a-d with LiAlH 4. From 10a-d with mercury-EDTA the same products are obtained as from 5a-d but without 7. Only the pyrrolidine 10a forms besides (E/Z)-3a the nitrone 4a. Thin-layer chromatography shows that the pure isomers of 3a-d in solution isomerize, contrary to the amine-oximes 1a-d. The configuration of the oxime-lactams depends on the manner of preparation. With mercury-EDTA, 1b,c yield 3b,c with retention of the configuration, while the oximation of phenacyl-lactams 13b,c give rise to (E/Z)-mixtures of 3b,c. The condensed imidazoles 12 result from the nitrones 4a-d and the dihydrooxadiazines 2a,d on treatment with hydrogen chloride.
