17-次乙二氧基-3-甲氧基-雌甾-2,5(10)-二烯-11β-醇用硅胶支持的草酸试剂选择性水解

The Selective Hydrolysis of з-Methoxy-estra-2, 5(10)-dien-11β-ol with an Oxalic Acid Reagent Supported on Silica Gel

以3-甲氧基一雌甾-1,3,5(10)-三烯衍生物,经Birch还原所得的3-甲氧基-雌甾-2,5(10)-二烯,是合成各种19-去甲甾体药物的重要前体,在甾体有机合成中有重要意义。在强酸条件下,水解3-甲基烯醇醚,将发生5(10)-双键移位,得到相应的共轭4-烯-3-酮化合物,同时。

Using oxalic acid reagent supported on silica gel 17-Cyclic ethylenedioxo-3-me- thoxy-estra-2,5(10)-dien-11β-ol(1) was converted into corresponding 3-one derivative without migration of 5(10)-alkene bond and hydrolysis of 17-cyclic acetal group. This selective hydrolysis was carried out in mild condition and easily to be controlled. The pro- duct can be isolated conveniently with 66.7% yield. This new method is obviously superior to the reported procedures. The product from reaction of 1 with 70% acetic acid or oxalic acid/methanol is a complicated mixture and difficult to be purified.