Ring-nor Steroids

Mercuric acetate opens the cyclopropane ring of 3a,5a-cyclocholestane to produce the non-mercurated A-nor steroid (318) in moderate yield. Base attacks the 4,4-dimethyldiosphenol (319) only at the C-3 carbonyl to give the ring-contracted hydroxyacid (320). Such 3,3-dimethyl-A-norcholest-5-enes are 

Hydride reduction of 3-oxo-A-nor-5jff-cholanoic acid afforded a preponderance of the 3a-hydroxy-compound, although the ratio of 3a 3) alcohols is less than with the normal six-membered homologues. Lithium-ammonia reduction afforded equal amounts of 3a- and 3)5-epimers. AB-Dinor-cholestenone and -testosterone have been prepared by the following sequence  

Cyclisation to the 3-en-2-one could be achieved by pyrolysis of the anhydride obtained by treatment of the diacid (322) with acetic anhydride, but better yields were obtained (especially in the cholestane series) by refluxing the seco-acid in acetic anhydride containing potassium cyanide. Catalytic reduction of the di-nor compound (323) gave the 5j -2-ketone which was ring-expanded to a 1 1 mixture of 5) -B-nor-2- and -3-ketones on treatment with diazomethane and boron trifluoride etherate. Neither AB-dinortestosterone nor its acetate exhibited androgenic or anti-androgenic activity. 

16a- and 16)3-Carboxylic acid D-norandrostanes are accessible by irradiation of 16-diazo-17-ketones. Both 16a- and 16 -acids (324) have been converted into the 16-acetyl, -acetoxy- and -hydroxy-derivatives and, by Curtius reaction, into the 16a- and 16)3-amines. Nitrous acid deamination of this latter amine afforded, after reduction with lithium aluminium hydride, a mbcture of epimeric c-homo-D-bisnor methyl alcohols (325) (69 %) and (326) (18 %). Solvolysis of the 16 -tosyloxy-derivative also produced the same two methyl alcohols, although in this instance (326) predominated. The 16a-amino-D-nor steroid afforded the 13,17-seco-alcohol (327) and, by a series of carbonium ion rearrangements, the cyclopropane (328) on deamination. 

Levisalles, and I. Tkatchenko, Bull. Soc. chim. France, 1969, 3189. 

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