New tetrodotoxin analogs, 5,6,11-trideoxytetrodotoxin and its 4-epimer
, were isolated from the puffer fish, Fugu poecilonotus, and the struc
tures were elucidated by spectroscopic methods, The discovery of the n
ew analogs is highly significant with respect to the biosynthesis of t
etrodotoxin.