The synthesis of the 3-glucuronides of 20α-cortolone and their 20β-epimers is described. The cortol 20, 21-diacetates (3, 10) and cortolone 20, 21-diacetates (6, 12) were the key intermediates. Sodium borohydride reduction of the carbonyl group at C-20 in 21-acetoxy-3α, 11β, 17α-trihydroxy-5β-pregnan-20-one 3-tert-butyldimethylsilyl ether (1) or its 11-oxo derivative (4) followed by acetylation of the product with acetic anhydride gave the silyl ether-acetates (2, 5), which, on removal of the protecting group at C-3 with sulfuric acid, were converted into the desired 20β-intermediates (3, 6). On the other hand, the 20α-acetates, 10 and 12, were synthesized from methyl 20α-acetoxy-3α-tert-butyldimethylsilyloxy-17α-hydroxy-11-oxo-5β-pregnan-21-oate (7). Introduction of the glucuronyl residue at the C-3 position was carried out by means of the Koenigs-Knorr reaction.
本文描述了 20α -
可的松酮的 3-
葡萄糖醛酸及其 20β -表聚物的合成过程。
可的松 20,21-二
乙酸酯(3,10)和
可的松 20,21-二
乙酸酯(6,12)是关键的中间体。
硼氢化钠还原 21-乙酰氧基-3α,11β,17α-三羟基-5β-孕甾-20-酮 3-叔丁基二甲基
硅醚(1)或其 11-氧代衍
生物(4)中 C-20 处的羰基,然后用
乙酸酐对产物进行乙酰化,得到
硅醚-
乙酸酯(2、5),用
硫酸去除 C-3 处的保护基团后,这些产物转化为所需的 20β 中间体(3、6)。另一方面,20α-
乙酸酯 10 和 12 是由 20α-acetoxy-3α-ter-butyldimethylsilyloxy-17α-hydroxy-11-oxo-5β-pregnan-21-oate 甲酯合成的(7)。通过柯尼希斯-克诺尔反应在 C-3 位置引入
葡萄糖醛酸残基。