Anticholinesterase activity huperzine

Alcala MDM, Vivas NM, Hospital S, et ai. Characterisation of the anticholinesterase activity of two new tacrine-huperzine A hybrids, Neuropharmacol... 

Campiani, G. Kozikowski, A. R Wang, S. Ming, L. Nacci, V. Saxena, A. Doctor, B. P. Synthesis and anticholinesterase activity of huperzine A analogues containing phenol and catechol replacements for the pyridone ring. Bioorg. Med. Chem. Lett., 1998, 8(11) 1413-1418. 

Kozikowski, A. R Campiani, G., Nacci, V., Sega, A., Saxena, A., Doctor, B. P. An approach to modified heterocyclic analogues of huperzine A and isohuperzine A. Synthesis of the pyrimidone and pyrazole analogues, and their anticholinesterase activity. J. Chem. Soc. Perkin Trans. 1, 1996, 11 1287-1297. 

Huperzine B has a molecular formula of C16H20N2O, m.p. 270-271 °C, [cx]d-54.2° (C, 0.2, MeOH). It has UV spectrum absorptions at Amax (log e) 231 (3.95), 312 (3.85), and IR spectrum absorptions at vmax 3100, 1670, 1620,1610,1560 cm-1. The whole structure was proposed by spectral analyses as shown in 5-3. Its main difference from huperzine A is the absence of exocyclic double bond which form an additional piperidine ring in 5-3. Huperzine B does not possess anticholinesterase activity. 

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