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The rearrangement of 9a.11 a-epoxy-5a-pregnane-3P-2Op-diyl diacetate (3) to 11 -oxo-Sa,SP-pregnane-3p,20pdiyl diacetate (4) and 11 a-hydroxy-9@-methyl-l9-norpregn-5(1 O)-ene-3p,20p-diyl diacetate ( 5 ) is reported. Treatment of the 5(1O)-ene (5) with m-chloroperbenzoic acid in benzene affords 5p.1 OP-epoxy-1 1 a-hydroxy-9Pmethyl-l9-norpregnane-3P,20@-diyl diacetate (1 1 ), whereas epoxidation with peracetic acid in acetic acid containing mineral acid (1 % H,SO,) leads to 5a.11 a-epoxy-1 O~-hydroxy-9~-methyl-l9-norpregnane-3P,20P-diyl diacetate (1 2) by rearrangement of the initially formed 5p.1 OP-epoxide (1 1).

5~-androsta-8,11 ,I 3-trien-3a-yl acetate (6) has been prepared from 9a.11 a-epoxy-l7amethyl-5(3-androstane-3a,l7(3-diol 3-acetate (5) in good yield. An attempt to repeat the aromatisation with the analogous 9a.11 cc-epoxy-5P-pregnane-3a,l7a,20P-triol 3,20-diacetate (1 0) did not give the expected product. However, a number of ring-c-aromatic pregnanes have been successfully prepared from derivatives of 5P-pregnane-3a.11 p.17a, . Attempts to aminate some of these aromatic pregnanes a t the 3-and 20-positions are described.PREVIOUS papers from our laboratories have described the preparation of an 18-norpregna-8,11,13-triene and 18-norandr0sta-8,11,13-trienes.~-~ In continuation of the study to evaluate the biological activities of ringc-aromatic steroids, some other novel syntheses of ringc-aromatic pregnanes have been developed and are described herein.Aromatisation of ring c of a steroid necessitates the removal or migration of the 13p-methyl group. There are a number of examples 2-6 of the concomitant shift of the 13-methyl group of a 17-hydroxy-steroid by way of a Wagner-Meerwein rearrangement to give the 17pmethyl-13-ene. I t seemed that application of this rearrangement to 17a-hydroxypregnanes containing one or two potential double bonds in ring c might lead to an efficient route to ring-c-aromatic pregnanes.

Das aus dem Pregnendiacetat (I) zugängliche Epoxid (II) lagert sich beim Umsetzen mit BF3‐ätherat in das Keton (III) und den Alkohol (IV) um.