Synthesis and Biological Activity of Enantiomeric Pairs of 5-(Alk-2-enyl)thiolactomycin and 5-[(E)-Cycloalk-2-enylidenemethyl]thiolactomycin Congeners

Abstract

The title compounds were synthesized by the efficient route previously explored for the synthesis of enantiomeric pairs of thiolactomycin and its 3-demethyl derivative. These studies were carried out to prove the flexibility of the previously explored synthetic route to natural thiolactomycin (TLM) 1 and to examine the structure–activity relationship on the 5-position of 1. While all of the synthesized congeners lacked in vitro antibacterial activity, these studies led us to find 5-(alk-2-enyl)-TLM (ent-4d) which exhibits mammalian type I fatty acid synthase (FAS) inhibitory activity equal to that of C75, a potent inhibitor reported previously. It was also found that 5-[(E)-cycloalk-2-enylidenemethyl]-TLM (ent-5c) exhibited slightly less potent mammalian type I FAS inhibitory activity than C75.