Photochemical Rearrangement of a Steroidal α, β‐Epoxylactam. Photochemical reactions, XII [1]

Abstract

SummaryThe UV. irradiation of 17B-hydroxy-4a, 5 a -epoxy-2-azaandrostan-3-one (1) yields 17@-hydroxy-2-aza-l0 (5 + 4-abeo)-45 (H)-androsta-3,5-dione (3).Introduction. -We have reported that steroidal lactones behave photochemically in a similar way to their carbocyclic counterparts: a,B-unsaturated lactones, for example, undergo the 'type A' [2] and the di-z-methane [3] rearrangements, while a,@-epoxylactones suffer the 10 (5 4 4 ) rearrangement to an abeo structure [l]. Therefore, as a part of a systematic study on the photochemical behaviour of heterocyclic steroids, we investigated the UV. irradiation of the a , B-epoxylactam 1 (Scheme).