p-Toluenesulfonic acid → (8S,10R,13S,14S)-3-methoxy-10,13-dimethyl-1,2,7,8,12,14,15,16-octahydrocyclopenta[a]phenanthren-17-one

참여 물질

반응 단계

11.5 g of 4,9(11)-androstadiene-3,17-dione [U.S. Pat. No. 3,441,559 (1969)]in 200 ml of dioxane is reacted with 20 ml of orthoformic acid trimethyl ester and 100 mg of p-toluenesulfonic acid. After 48 hours, 5 ml of pyridine is added to the solution, the latter is concentrated under vacuum, the residue taken up in ethyl acetate, washed with water, and dried over sodium sulfate. After chromatography of the crude product with a hexane-ethyl acetate gradient on silica gel containing 2% triethylamine, 9.2 g of 3-methoxy-3,5,9(11)-androstatrien-17-one is isolated; mp 153.4° C.

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