First total synthesis of (+/-)-3-hydroxy-11-norcytisine: structure confirmation and biological characterization.

The first total synthesis of the natural product 3-hydroxy-11-norcytisine (1), structurally related to cytisine (2), a benchmark ligand at neuronal nicotinic acetylcholine receptors (NNRs), has been achieved. The synthesis permits the unambiguous confirmation of the structure originally proposed for 1 and has enabled initial biological characterization of 1 and its related compounds against NNRs.