Five derivatives of territrem B [2], a potent acetylcholinesterase inh
ibitor isolated from a rice culture of Aspergillus terreus, were prepa
red from 2 as well as from its major metabolite, 4 beta-hydroxymethyl-
4 beta-demethylterritrem B [4]. The inhibitory activities of these der
ivatives against electric eel acetylcholinesterase (E.C. 3.1.1.7) were
tested and it was concluded that the enone and the pyrone groups pres
ent in 2 may play an important biological role.