This compound can be prepared by two different ways: 1) The Grignard reaction of 3-oximino-17-oxoestre-4,9,11-triene (I) with allylmagnesium bromide (II) in ether - benzene gives 3-oximino-17alpha-allyl-17-hydroxyestra-4,9,11-triene (III), which pyruvic acid - acetic acid . 2) The dehydration of 17alpha-allyl-11beta,17beta-dihydroxyestra-4,9-dien-3-one (IV) eith refluxing aqueous 60% formic acid.