The d iastereoisomeric 1-keto-2-methyl-7-methoxy-1, 2, 3, 4, 9, 10, 11, 12-octahy-drophenantlrene with m.p.116-117°, whose B/C ring has the same configuration as that of dl-estrone's, was readily obtained from Miescher's keto ester(A)by alkali hydrolysis.By means of the Reformatsky reaction between this ketone and methyl bromoacetate, methyl 1-hydroxy-2-methyl-7-methoxy-1, 2, 3, 4, 9, 10, 11, 12-octahydrophenanthrene-1-acetate was obtained.This hydroxy ester could be readily dehydrated to the unsaturated ester by means of thionyl chloride and pyridine.This ester, upon hydrolysis with methanolic potassium hydroxide, gave the potassium salt which, upon acidification with hydrochloric acid, yielded the unsaturated acid, (2-methyl-7-methoxy-1, 2, 3, 4, 9, 10, 11, 12-octahydro-1-phenanthrylidene)-acetic acid in excellent yield, m.p.193.5-195°.