| 20100298585 | METHOD FOR SYNTHESIS OF DIENOGEST FROM ESTRONE-3-METHYLETHER - A method for the synthesis of dienogest from 3-methoxy-estra-1,3,5-trien-17-one includes the steps of a) reacting 3-methoxy-estra-1,3,5-trien-17-one with alcohol in the presence of an acid in an organic solvent to form 3-methoxy-17,17-dialkoxy-estra-1,3,5-triene; b) subjecting the product of step a) to partial reduction by reaction with alkali metal in liquid ammonia; c) treating the product of step b) with mild acid; d) reacting the product of step c) with cyanomethyl lithium; e) treating the product of step d) with oxalic acid; and f) treating the product of step e) with pyridinium tribromide in pyridine to yield dienogest. | 11-25-2010 |
