Irradiation of 3,19-dioxo-17β-acetoxy-Δ4-androstene (2) at room temperature in either of its two absorption bands centered at about 245 and 315 nm, respectively, led to products 21, 22, and 23 (Chart 3). Compounds 21 and 22 result from rearrangements involving intramolecular formal 1,2- (21) and 1,3-shifts (22) of the angular formyl group, and the formation of compound 23 proceeds through the elimination
的照射3,19二氧代17β乙酰氧基Δ 4雄甾(2)在其两个吸收带的室温集中在大约245和315nm处,分别导致了产品21,22,和23(图3)。化合物21和22是由重排引起的,该重排涉及角甲酰基的分子内形式的1,2-(21)和1,3-移位(22),化合物23的形成通过消除甲酰基和引入来自介质的氢。有证据表明,后者是次要的自由基反应,而不是主要的光
化学步骤。