New cyclopentanophenanthrene derivatives and method for the preparation thereof
The invention comprises allopregnane3b : 11a : 17a : 21 - tetrol - 20 - one 21 - monoacetate, together with a process for the preparation of an allopregnane-17a : 21-diol3 : 11 : 20-trione 21-lower fatty acid acylate which comprises treating 22-isoallospirostan3b : 11a -diol with a lower fatty acid anhydride under pressure at a temperature of approximately 200 DEG C., to form a D 20(22)-allofurostene3b : 11a : 26-triol triacylate, thereafter oxidizing said triacylate with chromic anhydride in acetic acid, saponifying the oxidation product with alumina to form a D 16-allopregnene3b : 11a - diol-20-one diacylate, hydrogenating the D 16-compound to form the corresponding allopregnane - 3b : 11a - diol - 20 - one diacylate, enolizing the allopregnane-3b : 11a -diol-20-one diacylate to form the corresponding 20-enol acylate, oxidizing this with an aromatic per acid and saponifying the product to form allopregnane - 3b : 11a : 17a - triol - 20 - one, monobrominating this compound to form the 21-bromo derivative, treating the 21-bromo compound with sodium iodide and the potassium salt of a lower fatty acid to form the 21-monoacylate of allopregnane - 3b :11a :17a:21-tetrol-20-one, and oxidizing said tetrol with a mild oxidizing agent to form allopregnane - 17a :21 - diol - 3:11:20 - trione 21-lower fatty acid acylate. In an example: 22 - isoallospirostan - 3b :11a - diol is heated with acetic anhydride and the resultant D 20(22) - allofurostene - 3b :11a :26 - triol triacetate oxidized with chromium trioxide to D 16 - allopregnene - 3b :11a - diol - 20 - one diacetate, which is hydrogenated in ethyl acetate using palladized barium sulphate to produce allopregnane-3b :11a -diol-20-one diacetate. This compound is heated with acetic anhydride containing p-toluene sulphonic acid and the resultant D 17(20) - allopregnene-3b :11a :20 - triol triacetate treated with methanolic sodium hydroxide giving allopregnane - 3b :11a :17a - triol 20 - one, which is brominated in chloroform solution to 21 - bromo - allopregnane - 3b :11a :17a - triol-20-one. Treatment of the bromo compound with sodium iodide in acetone and then potassium bicarbonate in acetic acid produces allopregnane - 3b :11a :17a :21 - tetrol - 20-one 21-mono acetate, which is oxidized either with (a) chromic anhydride in acetic acid, or (b) N-bromoacetamide in pyridine to yield allopregnane - 17a :21:diol - 3:11:20-trione 21-acetate. Specifications 721,953 and 735,429 are referred to.