Photochemische Reaktionen. 33. Mitteilung. Die Photoisomerisierung von 3‐Oxo‐Δ1;4‐Steroiden in Dioxanlösung Strukturaufklärung der Photoisomeren und Bestimmung der Umlagerungs‐Sequenzen

The photo‐induced formation of ketonic and phenolic isomers from O‐acetyl‐1‐dehydro‐testosterone ( 1a ) and from its 4‐methyl homologue 1d in dioxane solution has been described earlier [8][9][13]. The present paper summarizes the findings which resulted in the course of further investigations, and which, in part, have been published in preliminary form [11][14] and in recent reviews [12]. This work includes the ultraviolet irradiation of dienone 1a , its 10α‐stereoisomer 2a , and its 1‐, 2‐ and 4‐methyl homologues 1b – d . A series of rearrangements occurred in each case, as shown in Charts 2, 3, and 19.