Wilsoniamines A and B: novel alkaloids from the temperate Australian bryozoan, Amathia wilsoni

Two novel alkaloids, wilsoniamines A and B, both possessing a hexahydropyrrolo[1,2-c]imidazol-1-one ring system that has not previously been found in nature, together with a new alkaloid, amathamide H and a known alkaloid, amathamide C were isolated from the temperate Australian bryozoan, Amathia wilsoni. MS and NMR analysis established the structure of the new compounds and indicated that the structure of amathamide C and several related compounds be revised. Amathamides C and H showed moderate anti-malarial and anti-trypanosomal activity.