The Beckmann fragmentation reaction of some α-hydroxy ketoximes

Abstract

The Beckmann fragmentation reaction of 3β,17β-dibydroxy-16-oximino-5-androstene (2) and 2-exo-hydroxy-3-oximinobornane (8) was readily achieved with p-toluenesulfonyl chloride in pyridine at 0° or by short boiling with 20% (v/v) H2SO4. The structures of the primary fragmentation products 3 and 9 were deduced on the basis of spectral and analytical properties of the corresponding 2,4-dinitrophenylhydrazones 4 and 10; in addition, 3 was converted into the known lactone 6. Anti configurations were assumed for the hydroxy oximes 2 and 8 obtained by NaBH4 reduction of 1 and 7, based on studies of the NaBH4 reduction of syn- and anti-benzil monoximes.