Synthetic Studies toward the Total Synthesis of Hoiamides

Hoiamides are a new class of marine secondary metabolites isolated from cyanobacteria collected in Papua New Guinea. They comprised of a triheterocyclic fragment bearing two alpha-methylated thiazolines, one thiazole, and a highly oxygenated and methylated polyketide substructure. Both hoiamides A and B are 26-membered cyclodepsipeptides. Hoiamides C and D are the linear analogues of hoiamide A. Despite that hoiamide C has no significant activity, hoiamides A and B stimulated sodium influx with EC₅₀ values of 1.7 and 3.9µM, respectively, in mouse neocortical neurons. The detailed synthetic studies toward hoiamides A & C will be presented.