Spiro-prorocentrimine, a novel macrocyclic lactone from a benthic Prorocentrum sp. of Taiwan

Spiro-prorocentrimine, C42H69NO13S, is a polar lipid-soluble toxin isolated from a laboratory-cultured benthic Prorocentrum species of Taiwan, crystallized in methanol. X-ray diffraction analysis of the compound revealed a spiro-linked cyclic imine with the ortho, para-disubstituted 3′-cyclohexene in addition to its macrolide skeleton. 13C and 1H NMR signals were then assigned accordingly. This is the first compound of this group of marine toxins with a clear stereochemistry.