Synthesis and antimicrobial activity of 7-fluoro-3-aminosteroids.

A series of 7-fluoro-3-aminosteroids were synthesized and their in vitro antimicrobial activities were evaluated against Gram-positive and Gram-negative bacteria. The nucleophilic fluorination of several 7beta-hydroxysteroids by diethylaminosulfur trifluoride in n-pentane, followed by reductive amination of the resulting 7-fluoro-3-ketosteroids with spermidine in the presence of NaBH(3)CN, afforded 7-fluoro-3-aminosteroids in high yield. Compound 25 showed the highest antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus pyogenes, and Escherichia coli.