Epiquinamide: a poison that wasn't from a frog that was.

摘要: In 2003, we reported the isolation, structure elucidation, and pharmacology of epiquinamide (1), a novel alkaloid isolated from an Ecuadoran poison frog, Epipedobates tricolor. Since then, several groups, including ours, have undertaken synthetic efforts to produce this compound, which appeared initially be novel, beta2-selective nicotinic acetylcholine receptor agonist. Based on prior chiral GC analysis natural samples, absolute was established as (1S,9aS)-1-acetamidoquinolizidine. We synthesized (1R*,9aS*)-isomer (epi-epiquinamide) using iminium ion nitroaldol reaction key step. also ent-1 semisynthetically (-)-lupinine. Synthetic is inactive at receptors, in accord with recently published reports. determined that activity due cross-contamination co-occurring epibatidine material.