Preparation of secolycorines against acetylcholinesterase

Secolycorines were facilely prepared from lycorine and some of them are more potent than galanthamine against acetylcholinesterase. 5,6-Secolycorines possessing a 5,6-dihydrophenanthridine skeleton were facilely prepared from lycorine through chemical transformations, mainly including N-alkylation, Hofmann degradation type reaction, reductive cleavage of trichloroethylcarbonyl moiety, and hydrogenation. Several secolycorine derivatives showed potent inhibitory activity against acetylcholinesterase with the IC 50 value at micromolar range and are more potent than galanthamine.