8-Aminobicyclo[3.2.1]octanes: synthesis and anti-viral activity

A series of 8-chlorobicyclo[3.2.1]oct-6-enes has been prepared from cyclohexenyl chlorides and simple alkynes via a one-step [3+2] cycloaddition methodology, and then converted into the corresponding bicyclic amines. Against influenza-A virus a number of these showed in vitro activity, and amine (2) was comparable to amantadine in vivo. Good activity against influenza-B virus was less common, and none of the amines showed high potency against both viruses. Amines (20) and (23) showed significant activity versus respiratory syncytial virus.