Synthesis and bioactivity of linear oligomers related to polymeric alkylpyridinium metabolites from the Mediterranean sponge Reniera sarai.

Dimers and tetramers of linear 3-alkylpyridinium salts have been synthesized by an efficient synthetic pathway, which is also applicable to the preparation of higher oligomers. Mono-, di- and tetrameric compounds have been tested for antibacterial and hemolytic activities and for the inhibition of acetylcholinesterase and protein phosphatase 2A. Their activities were compared to those of the natural poly-3-octylpyridinium alkaloids isolated from the Mediterranean sponge Reniera sarai. Relatively high antibacterial and anti-acetylcholinesterase activities were observed that increase with higher degrees of oligomerization.