GONIODENIN, A NEW BIOACTIVE ANNONACEOUS ACETOGENIN FROM GONIOTHALAMUS-GIGANTEUS AND ITS CONVERSION TO TRI-THF ACETOGENINS

Using activity-directed fractionation, a novel bioactive bis-THF acetogenin, goniodenin (1), has been isolated from the bark of Goniothalamus giganteus (Annonaceae). 1 is the first reported bis-THF acetogenin which bears a double bond in the aliphatic chain. The cis C-21/22 double bond in 1 was efficiently oxidized to the epoxides and cyclized to produce a pair of tri-THF acetogenins, cyclogoniodenins T and C (8 and 13). These are the first reported semi-synthesized tri-THF acetogenins, and 13 represents a new type of acetogenin. The absolute stereochemistries were assigned using Mosher ester and nmr analyses. 8 and 13 show interesting selectivities among several human tumor cell lines. Asimilobin (19), concurrently found in the seeds of Asimina triloba, was also isolated and characterized.