Synthesis and evaluation of novel 4-amino-4,6-androstadiene-3,17-dione: an analog of formestane. 
Synthesis of 4-amino-4,6-androstadiene-3,17-dione 7, an analog of formestane used in breast cancer therapy as an aromatase inhibitor, from 4-acetoxy-4-androstene-3,17-dione 2 is described.  This is the first report of a 4-amino diene (4,6) system in this series of molecules.  The new (7) and reported molecules were screened by the National Cancer Institute (NCI, Bethesda, USA) for in vitro antitumor activity against 60 human cancer cell lines.  Molecule 7 showed best activity against breast cancer cell line (MCF-7).