19-nor-progesterone derivatives

The invention comprises compounds of formula wherein X is a hydrogen or halogen atom, and R and R1 are hydrogen atoms or in combination a group wherein Q is an alkyl, haloalkyl, cycloalkyl, cycloalkyl-alkyl, aryl, aralkyl, heterocyclyl or heterocyclyl-alkyl group and P is a hydrogen atom or one of Q, and their preparation by (i) reaction of a compound of formula with an alkyl orthoformate to give the corresponding 3-alkoxy-D 3,5-compound, halogenating this to give the corresponding 3-keto-6-halo-D 4-compound, and treating this with either (a) for example choranil, to give the 6-halo-D 4,6-compounds of the invention, or (b) a dehydrohalogenating agent to give the 6-unsubstituted-D 4,6- compounds of the invention, followed, if desired, by epoxidation to give the corresponing 4a ,5a -oxido compound and treating this with a hydrohalic acid to give a 6-halo-D 4,6-compound of the invention, (ii) hydrolysis to the 16a , 17a -diol with formic acid, or (iii) reaction of the 16a ,17a -diol with an appropriate aldehyde or ketone. The compounds of the invention have progestational activity and may be used in pharmaceutical compositions in combination with a carrier, for example in forms suitable for oral administration.