title: Identification and Characterization of Pectenotoxin (PTX) 4 and PTX7 as Spiroketal Stereoisomers of Two Previously Reported Pectenotoxins.
abstract: Pectenotoxins (PTXs) isolated from the scallop Patinopecten yessoensis were shown to be involved in an episode of diarrhetic shellfish poisoning (DSP). A total of eight analogues (PTX1-PTX7 and PTX10) have been isolated to date, and the structures of four of these analogues (PTX1, PTX2, PTX3, and PTX6) have already been elucidated. Here, we report the characterization of PTX4 and PTX7 as 7-epi-PTX1 and 7-epi-PTX6, respectively, on the basis of NMR data and an acid-catalyzed chemical interconversion. The structures of two new artifacts, PTX8 and PTX9, produced following this treatment are also reported.
authors.affiliation: Faculty of Agriculture, Tohoku University, Tsutsumidori-Amamiya, Aoba-ku, Sendai 981, Japan; Institute for Marie Biosciences, National Research Council of Canada, 1411 Oxford Street, Halifax, Nova Scotia, Canada B3H 3Z1.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Sasaki
authors.forename: Jeffrey L. C.
authors.initials: JL
authors.lastname: Wright
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yasumoto