Abstract: New 15,15-dialkyl-substituted derivatives of the estradiol of general formula I ##STR1## in which R.sup.1 and R.sup.2, independently of one another, are each a hydrogen atom or a straight-chain alkanoyl group with 1 to 10 carbon atoms, a branched-chain alkanoyl group with 3-10 carbon atoms, an alkanoyl group of 3-10 carbon atoms containing a cycloaliphatic structure of 3-6 carbon ring atoms or a benzoyl group, andR.sup.3 and R.sup.4, independently of one another, are each a straight-chain alkyl group with 1 to 10 carbon atoms or a branched-chain alkyl group with 3 to 10 carbon atoms,are described, a process for their production and initial products for this process.The new compounds have--also after oral administration--high estrogenic effectiveness and are suitable for the production of pharmaceutical agents.

Abstract: 14.alpha.,17.alpha.-(Propano-and 17.sup.2 -propeno)-estratrienes of general formula I ##STR1## in which R.sup.1 means a hydrogen atom, a methyl or an acyl group with 1-12 carbon atoms,R.sup.2 means a hydrogen atom or an acyl group with 1-12 carbon atoms and ##STR2## a C--C single or double bond. The new compounds of general formula I are estrogen effective just as ethinyl estradiol.

Abstract: 14,16.beta.-Ethano-15.beta.,16.sup.1 -cyclo-14.beta.-estra-1,3,5(10)-trienes of general formula I ##STR1## in which R.sup.1 means a hydrogen atom, a C.sub.1 to C.sub.9 alkyl or C.sub.1 to C.sub.9 acyl radical,R.sup.2 means a hydrogen atom, a C.sub.1 to C.sub.9 alkyl radical, a C.sub.2 to C.sub.9 alkenyl or alkinyl radical andR.sup.3 means a hydroxy group or a C.sub.1 to C.sub.9 acyloxy radical, as well as a process for their production are described. The new compounds have high (peroral) effectiveness and are suitable for the production of pharmaceutical agents.

Abstract: 14,17.beta.-ethano-14.beta.-estratriene and estratetraene of Formula I ##STR1## wherein R.sup.1 is a hydrogen atom, a methyl or an acyl group of a monocarboxyclic acid of 1-12 carbon atoms,R.sup.2 is a hydrogen atom or an acyl group of a monocarboxylic acid of 1-12 carbon atoms,R.sup.3 is a hydrogen atom or a methyl group, and ##STR2## is a single or double C--C-bond show strong estrogenic activity.