Amazing new alkaloid skeletons from the marine sponge Reniera sarai

Abstract

Reniera sarai possesses two homologous series of alkaloids, sarains 1–3 and sarains A-C, along with some related minor metabolites which include isosarain-1 (1). We now report the complete structural elucidation of 1_, which supports and further clarifies the previously only partially characterized structures of sarains 1–3. X-ray structure of an acetate derivative of sarain-A has discovered an amazing new ma-crocyclic alkaloid skeleton. All the sarains have been characterized by an extensive use of 2D NMR methods. © 1989 IUPAC