Beckmann rearrangement of some steroid α-hydroxy ring B ketoximes: 5-oxo 5,6-seco nitriles

Abstract

Five steroid α-hydroxy ring B ketoximes (1)-(5) were subjected to Beckmann rearrangement using thionyl chloride and potassium hydroxide. In each case the products resulted from second-order Beckmann cleavage. In the case of the dioxime (5), the product obtained was a lactam nitrile (11).The C3-substituted oximes (1) and (2) gave, besides the corresponding nitriles (8) and (9), the chloronitrile (6) and the α,β-unsaturated keto nitrile (7). A probable pathway for the formation of (6) from (1) has been suggested. The mass spectra of the nitriles (6)-(10) showed a pronounced peak at m/e 110, resulting from the McLafferty rearrangement involving a C8 and/C11-hydrogen and the C5-keto function. Interestingly, the mass spectrum of (11) did not show the corresponding peak at m/e 141.