Synthesis of Aristoquinoline Enantiomers and Their Evaluation at the α3β4 Nicotinic Acetylcholine Receptor.

The first synthesis of aristoquinoline (1), a naturally occurring nicotinic acetylcholine receptor (nAChR) antagonist, was accomplished using two different approaches. Comparison of the synthetic material's spectroscopic data to that of the isolated alkaloid identified a previously misassigned stereogenic center. An evaluation of each enantiomer's activity at the α3β4 nAChR revealed that (+)-1 is significantly more potent than (-)-1. This unexpected finding suggests that naturally occurring 1 possesses the opposite absolute configuration from indole-containing Aristotelia alkaloids.