A method of preparing octahydrophenanthrene carboxylic acids with estrogenic activity

摘要

Substituted 1, 2, 3, 4, 9, 10, 11, 12-octahydrophenanthrene-2-carboxylic acids of the general formula: FORM:0865972/IV (b)/1 wherein R1 represents a methoxy, ethoxy or hydroxy group, R2 represents a methyl group and R3 represents an alkyl group containing 1 to 3 carbon atoms, are prepared by heating alicyclic lactones of the general formula: FORM:0865972/IV (b)/2 wherein R1 represents a methoxy or ethoxy group and R2 and R3 have the above significance, with catalysts of the Friedel Crafts type in the presence of free hydrogen halides. Suitable catalysts are aluminium chloride, stannic chloride and boron trifluoride. The compounds in which R1 represents a hydroxy group may also be prepared by dealkylation of the corresponding compounds in which R1 represents a methoxy or ethoxy group e.g. by heating with the hydrochloride of a nitrogen base such as pyridine hydrochloride. The above processes always yields a mixture of stereoisomeric carboxylic acids of the above general formula which may be resolved by methylation to form the corresponding methyl esters e.g. with dimethyl sulphate in an alkaline aqueous solution, and/or by heating with excess diazomethane in ether solution separating the methyl esters by fractionating the methyl esters under reduced pressure or by submitting them to chromatography, saponifying the methyl esters by heating at 170-180 DEG C. with excess potassium hydroxide wetted with alcohol and water, and purifying the free acids by converting them into their sodium salts, recrystallizing the salts from aqueous solutions and isolating the free acids by acidification. In the examples the following compounds are prepared:- 1-ethyl-2-methyl-7-methoxy (and hydroxy)- 1, 2, 3, 4, 9, 10, 11, 12-octahydrophenanthrene-2-carboxylic acid and the corresponding methyl esters. Specification 830,082 is referred to.