Photochemische Reaktionen. 26. Mitteilung. Zur UV.‐Bestrahlung von O‐Acety1‐1‐dehydro‐2‐methyl‐testosteron. (Vorläufige Mitteilung)

The ultra‐violet irradiation of O‐acetyl‐1‐dehydro‐2‐methyl‐testosterone ( 1 ) in dioxane solution leads to a mixture of ketonic and phenolic isomers from which five components ( 2 – 6 ) have been isolated. The structures of ketones 2 and 4 have been established. The sequence of photochemical rearrangements is 1 → 2 → 3 . Evidence points to the intermedi acyof an isomer of type e and the formation of compounds 4 and 5 from 3 . Structural formulas for 3 (= g ) and 5 (= j ) are advanced on this basis. The close relationship between the sequences of rearrangements initiated by the irradiation of O‐acetyl‐1‐dehydro‐testosterone and its 2‐methyl homologue ( 1 ), respectively, is discussed.