Enantioenriched N-(2-Chloroalkyl)-3-acetoxypiperidines as Potential Cholinotoxic Agents. Synthesis and Preliminary Evidence for Spirocyclic Aziridinium Formation.

Article abstract of DOI:10.1016/0040-4020(95)00285-G

The syntheses of six enantioenriched analogs representing cyclic forms of acetylcholine are reported. (S)- and (R)-N-(2-chloroethyl)-3-acetoxypiperidine and (R,R)-, (R,S)-, (S,R)-, and (S,S)-N-(2-chloropropyl)-3-acetoxypiperidine have been synthesized from (R)- or (S)-3-hydroxypiperidine in five steps. (R)- and (S)-3-hydroxypiperidine were accessed via parallel stereospecific routes from d- and l-glutamic acid, and through fractional recrystallization of diastereomeric tartranilic acid salts. (S)-N-(2-Chloroethyl)-3-acetoxypiperidine was reacted with silver perchlorate to form a spirocyclic aziridinium analog of acetylcholine as evidenced by a characteristic 1H NMR shift for the aziridinium methylene groups.