1. Liu, J. S.; Zhu, Y.-L.; Yu, C.-M.; Zhou, Y.-Z.; Han, Y.-Y.; Wu, F.-W.; Qi, B.-F. Can. J. Chem. 1986, 64, 837. Huperzine A proved to be identical with selagine, an alkaloid extracted from Lycopodium selago, see: Yoshimura, H.; Valenta, Z.; Wiesner, K. Tetrahedron Lett. 1960, 12, 14 and Ayer, W. A.; Browne, L. M.; Orszanska, H.; Valenta, Z.; Liu, J.-S. Can. J. Chem. 1989, 67, 1538.
2. (a) Kozikowski, A. P. J. Heterocycl. Chem. 1990, 27, 97.
3. (b) Bai, D. Pure Appl. Chem. 1993, 65, 1103. For recent reviews on the chemistry and pharmacology of huperzine
4. A, see: (c) Kozikowski, A. P.; Tückmantel, W. Acc. Chem. Res. 1999, 32, 641.
5. (d) Tang, X. C.; He, X. C.; Bai, D. L. Drugs Future 1999, 24, 647.