
TY  - JOUR
A1  - Collins, DJ 
A1  - Krause, NE 
T1  - Monoacetals Derived From 12-&#945;-Hydroxyandrosta-1,4-diene-3,17-dione and Androsta-1,4-diene-3,12,17-trione
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1988
VL  - 41
IS  - 6
SP  - 985
EP  - 993
KW  - 
UR  - https://doi.org/10.1071/CH9880985 
N2  - Conversion of 12&#945;-hydroxyandrosta-1,4-diene-3,17-dione (5) into the corresponding 17-cyclic ethylene acetal (1) was accompanied by acid- catalysed attack of ethylene glycol at C3 to give 17,17-ethylenedioxy- 3-(2&#8242;-hydroxyethoxy)-1-methylestra-1,3,5(10)-trien-12a-ol (2), which was the major product with prolonged reaction times. Exchange dioxolanation of androsta-1,4-diene-3,12,17-trione (8), prepared by Jones oxidation of (5), gave selectively the 12-monoacetal (9): the regioisomeric 17-monoacetal (4) was obtained by oxidation of the hydroxy  acetal (1) with chromium trioxide in pyridine. The trione (8) likewise afforded selectively the 12,12-ethylenedithio acetal (11). Treatment of the trione (8) with p- toluenesulfonic acid in refluxing benzene gave 1-hydroxy-4-methylestra-1,3,5(10)-triene-12,17- dione (7a). 
ER  -

