184781-91-7Relevant academic research and scientific papers
Epiquinamide: A Poison That Wasn't from a Frog That Was
Fitch, Richard W.,Sturgeon, Gordon D.,Patel, Shaun R.,Spande, Thomas F.,Garraffo, H. Martin,Daly, John W.,Blaauw, Richard H.
, p. 243 - 247 (2009)
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 to be a novel, β2-selective nicotinic acetylcholine receptor agonist. Based on prior chiral GC analysis of synthetic and natural samples, the absolute structure of this alkaloid was established as (15,9aS)-1-acetamidoquinolizidine. We have synthesized the (1.R*,9aS*)-isomer (epiepiquinamide) using an iminium ion nitroaldol reaction as the key step. We have also synthesized ent-1 semisynthetically from (-)-lupinine. Synthetic epiquinamide is inactive at nicotinic receptors, in accord with recently published reports. We have determined that the activity initially reported is due to cross-contamination from co-occurring epibatidine in the isolated material.
