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

Synthesis of spirolactams via Diels-Alder addition of 1,3-butadienes to an α-methylene lactam

“…Addition of cyclopentadiene to α-methylenelactam 7 in dichloromethane at room temperature for 3 h in the presence of 20 mol% [(S,S)- 3 , albeit in an attempt to prepare racemic Diels-Alder adduct with diene 7, proved equally unrewarding. In summary the work reported herein focuses on the use of bis(oxazoline)-copper (II) complexes as chiral catalysts for the development of an asymmetric addition of 1,3-butadienes to α-methylenelactams.…”

“…This 6,6-spirocyclic ring system is also present in the fast acting toxin spiro-procentrimine 3 isolated from a Taiwanese laboratory-cultured Procentrum species. Macrocyclic toxins, spirolides A-D 2-5, 4,5,6 isolated from the digestive glands of contaminated mussels (Mytilus edulis), scallops (Placopecten magellanicus) and toxic plankton from the eastern coast of Canada, contain a homologous 7,6-spirocylic imine ring system.…”

Spirolides and Cyclic Imines: Toxicological Profile

“…1), whose chemical structure contains a 25-membered carbo-macrocycle and a 15-membered macrocyclic lactone arranged around a 6,6-spiroimine ring system. The overall structure and the stereochemistry of substituents have been unambiguously determined by X-ray crystallography (Lu et al 2001). …”

“…injection, prorocentrolide A had an animal lethality of 0.4 mg/kg mouse (Torigoe et al 1988), while spiro-prorocentrimine exhibited much less toxicity (i.e., animal lethality occurred at 2.5 mg/kg mouse) than other known marine cyclic imine toxins (Lu et al 2001). The molecular targets for these cyclic imine toxins have not yet been determined, because of the lack of purified or synthetic toxins.…”

Biomimetic Syntheses of Alkaloids with a Non‐Amino Acid Origin

“…Members of this family of natural compounds include symbioimine, pinnatoxins, pteriatoxins, and gymnodimines that will be discussed in the following sections, but also spirolides [13], prorocentrolides [14], and spiroprorocentrimine [15], which are presented in Figure 8.2 but will not be detailed any further.…”