COMMUNICATIONS TO THE EDITOR
Ia, R = H b, R = Ac
reacts readily with a,P-unsaturated ketones but not at all with saturated 20-kefostermds, the acetate I b was converted to the oily enol acetate 11, which without isolation was treated with 1.1 moles of monoperphthalic acid in ether solution a t room temperature. After 40 hours, there crystallized directly5 from the ether solution in over 70% over-all yield (based on Ib) As(e)-allopregnene-7,20-dione-3/3, 1ladiol 3-monoacetate (IVa) (m.p. 192-194", [ a l z 0 ~ +14", XEzH 252 mp, log e 4.12, Xg?:" 1728, 1700 and 1670 cm.-' and free hydroxyl band, found: C, 71.29; H, 8.39), which upon acetylation gave the identical diacetate I V b described above. Hydrogenation of IVa with palladized charcoal afforded 81% of allopregnane-7,20-dione-3P,ll a-diol 3-acemax. tate (VIa) (m.p. 1&.1-186'), [aI2O~-IO", hnujo' 1736, 1718 and 1700 ern.-' and free hydroxyl band, found: C, 70.96; H, 8.85), identified further by conversion to the known (vide supra) 3,ll-diacetate VIb. A particularly attractive feature of the present process is the facile preparation of 3-acylated-1 l a 01s (e.g., IVa, VIa), which allows interconversion with intermediates employed by other workers3p6 for the introduction of an 11-keto group. As an illustration, chromium trioxide oxidation of the monoacetate IVa smoothly yielded A8(g)-allopregnene7,11,20-trione-3P-ol acetate (V) (m.p. 171-173", [CY]~OD +50°, Xzi:H 268 mp, log a 3.82, found: C, 71.63; H, &OS), while similar treatment of VIa afforded allopregnane-7,11,20-trione-3P-olacetate ~ found: C, (VIc) (m.p. 209-211', [ a l Z o4-20', 71.25; H, 8.40).
I1
I
CHI
I
C=O
IVa, R = Ac, R' = H b, R = R' = Ac
I
I11
\
AcO/bid\O H V
OH VIa. R = Ac, R's =
