Isomeric oximes of 30-norlupan-20-one and its derivatives

30-Norlupan-20-one ( Ib ) and its derivatives IIb-Vb were converted into 5 : 1-10 :1 mixtures of relatively stable E and Z oximes Ic,d-Vc,d . Beckmann rearrangement of the oxime mixtures (as obtained from the oximation) afforded isomeric amides VIII-XII and XIII-XVI in the ratios 3.5 : 1 to 5 : 1. Oximes Vc,d with the E-ring bridged by a lactone grouping, react with difficulty and the rearrangement was proved only for the Z -isomer Vd .