rac-Huperzine A, its rac-7-ethyl-derivative and two regioisomeric analogue have been prepared though synthetic sequences involving the elaboration of the pyridisne ring in a late stage, by reaction of an intermidiate pyrrolidine enamine with propiolamide, which gave mixtures of regioisomeric pyridone derivatives. The acetylcholinesterase inhibitory activity of these and two other recently described 11-unsubstituted huperzine A analogues was determined, the rac-7-ethyl analogue of huperzine A being the most active compound, although it is about 12-fold less active than (-)- huperzine A. (C) 2000 Elsevier Science Ltd.
- Acetylcholinesterase inhibitory activity
- Biologically active compounds
- Polycyclic heterocyclic compounds