Synthesis and biological effect of halogen substituted phenyl acetic acid derivatives of progesterone as potent progesterone receptor antagonists

The overall data showed that steroids 8a, 8f, 8e and 8c have a high and selective binding activity to the PR. Furthermore there is a relationship between the structure of these steroids and their binding activity, since the presence of fluorine atom in meta position in the acetoxyphenyl substituent at C-17, improved the binding activity as compared to that for the ortho and para positions. These data also demonstrated that 8a-8f have an anti-progestational activity in vivo, and therefore they have better characteristics than the compounds previously reported.