The effect of the nature of the substituent at the nitrogen atom on transformations of 3-bromo-2,2,6,6-tetramethyl-4-piperidinone and its 1-hydroxy and 1-oxyl derivatives under conditions of the Favorsky rearrangement

3-Bromo-2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl reacts with NH₄OH to give 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl, a product of the Favorsky rearrangement. 3-Bromo-2,2,6,6-tetramethyl-4-piperidinone is transformed under these conditions into a bicyclic amino ketone, while its 1-hydroxy derivative affords acyclic nitrosoenone. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1189–1191, June, 1997.