| abstract |
Procedure for the preparation of estetrol of formula (I), ** (See formula) ** from the compound of formula (II) ** (See formula) ** characterized in that (a) a compound of formula ( II) in a suitable solvent using a suitable reagent to provide a compound of general formula (III) ** (See formula) ** in which R = methyl group or hydrogen, (b) the benzyl protecting group is removed at the position 3 by transfer or catalytic hydrogenation to provide a compound of general formula (IV) ** (See formula) ** in which R = methyl group or hydrogen, (c) is deprotected in an alkaline medium with an alkali metal carbonate, alkali metal hydrogen carbonate or alkali metal hydroxides in a suitable solvent. |