Numazawa M, Shelangouski M, Nakakoshi M
Tohoku Pharmaceutical University, 4-4-1, Komatsushima, Aobaku, 981-8558, Sendai, Japan.
Steroids. 2001 Oct;66(10):743-8. doi: 10.1016/s0039-128x(01)00103-9.
Treatment of enol acetates of 3beta-acetoxyandrost-5-en-17-one and its 5alpha-reduced analog, 5alpha-androstan-17-one, and estrone acetate, 1-4, with Pb(OCOCH(3))(4) in acetic acid and acetic anhydride gave the previously unreported products, 16beta-(acetoxy)acetoxy-17-ketones 8-10 and 12, in 9-15% yields along with the known major products, 16beta-acetoxy-17-ketones 5-7 and 11. Similar treatment of the 16beta-acetoxy-17-ketones with the lead reagent did not yield the corresponding (acetoxy)acetates. Reaction of the enol acetate 3 with Pb(OCOCD(3))(4) in CD(3)COOD yielded principally the labeled (acetoxy)acetate 10-d(3), which had a CD(3)COOCH(2)COO moiety at C-16beta. In contrast, when the deuterated enol acetate 3-d(3), which was obtained by treatment of the 17-ketone 14 with (CD(3)CO)(2)O in the presence of LDA and which had a CD(3)COO moiety at C-17, was reacted with Pb(OCOCH(3))(4), the resulting product was the labeled compound 10-d(2). This product had a CH(3)COOCD(2)COO function at C-16beta. Based on these results, along with further isotope-labeling experiments, it seems likely that the (acetoxy)acetate is produced through a lead (IV) acetate-catalyzed migration of the 17-acetyl function of the enol acetate to the C-16beta-position followed by attack of an acetoxy anion of the lead reagent.
在乙酸和乙酸酐中，用四乙酸铅[Pb(OCOCH(3))(4)]处理3β - 乙酰氧基雄甾 - 5 - 烯 - 17 - 酮及其5α - 还原类似物5α - 雄甾烷 - 17 - 酮以及醋酸雌酮（1 - 4），得到了之前未报道的产物，即16β - (乙酰氧基)乙酰氧基 - 17 - 酮8 - 10和12，产率为9% - 15%，同时还得到了已知的主要产物16β - 乙酰氧基 - 17 - 酮5 - 7和11。用铅试剂对16β - 乙酰氧基 - 17 - 酮进行类似处理，并未得到相应的(乙酰氧基)乙酸酯。乙酸烯醇酯3与四乙酸铅[Pb(OCOCD(3))(4)]在CD(3)COOD中反应，主要生成标记的(乙酰氧基)乙酸酯10 - d(3)，其在C - 16β处有一个CD(3)COOCH(2)COO部分。相比之下，当用LDA存在下的(CD(3)CO)(2)O处理17 - 酮14得到的在C - 17处有一个CD(3)COO部分的氘代乙酸烯醇酯3 - d(3)与四乙酸铅[Pb(OCOCH(3))(4)]反应时，得到的产物是标记化合物10 - d(2)。该产物在C - 16β处有一个CH(3)COOCD(2)COO官能团。基于这些结果以及进一步的同位素标记实验，(乙酰氧基)乙酸酯似乎是通过乙酸铅(IV)催化烯醇乙酸酯的17 - 乙酰官能团迁移至C - 16β位，随后铅试剂的乙酰氧基阴离子进攻而产生的。
