BECKMANN-Umlagerung und Fragmentierung. II. Teil. Versuche zur 7-Zentren-Fragmentierung von γ-Aminoketoximen. Fragmentierungsreaktionen, 19. Mitteilung

The occurrence of so-called synchronous 7 -centre-fragmentation has been excluded for γ-amino-ketoxime derivatives N? C? C? C? C?N? X. Fragmentation may occur, however, by another route. Reaction rates of the p-toluenesulfonates of (4-quinuclidinyl)-methyl-ketoxime ( 10b ) and (3β-tropanyl)-methyl-ketoxime ( 14b ) in 80% ethanol and the resulting products have been determined. Whereas the latter γ-aminoketoxime underwent quantitative BECKMANN rearrangement to 3β-acetylaminotropane ( 29 ), the former yielded 3% fragmentation products besides rearranged 4-acetylamino-quinuclidine ( 13 ). A kinetic study reveals that both 10b and 14b react via the rearranged nitrilium ions 12a and 16a , respectively. In the case of the N-(4-quinuclidinyl)-acetonitrilium ion ( 12a ) 5-centre-fragmentation competes with hydration to the amide 13 .