Syntheses of the Proposed Structures of Poison-Frog Alkaloids 179 and 207E and Their Inhibitory Effects on Neuronal Nicotinic Acetylcholine Receptors

Syntheses of the structures postulated for 179 and 207E, members of a proposed new class of poison-frog alkaloids, 6,7-dehydro-5,8-disubstituted indolizidines, are described. The FT-IR spectrum and GC retention time of the synthetic 207E were different from those of the natural product; consequently the original structure of 207E needs to be revised. It is likely that the position of the double bond is instead at the 7,8-position.