(2,4-CIS AND TRANS)-GIGANTECINONE AND 4-DEOXYGIGANTECIN, BIOACTIVE NONADJACENT BIS-TETRAHYDROFURAN ANNONACEOUS ACETOGENINS, FROM GONIOTHALAMUS-GIGANTEUS

Two new acetogenins, (2,4-cis and trans)-gigantecinone (1), isolated a s a mixture, and 4-deoxygigantecin (2), a known acetogenin whose absol ute stereochemistry has not been determined previously, were isolated using activity-directed fractionation, from the bark of Goniothalamus giganteus. A key step in solving their absolute stereochemistries was the preparation of 1,4-diol formaldehyde acetal derivatives (1b and 2a ). Using the advanced Mosher ester method and circular dichroism, the absolute stereochemistries of I and 2 were revealed and were found to be the same as that of gigantecin (3), which supports a common biogene tic origin. Both 1 and Ib showed potent and selective cytotoxicities a gainst the PC-3 human prostate adenocarcinoma cell line. Against yello w fever mosquito larvae, 1 and 2 were more potent than rotenone in pes ticidal activity. Longimicin C and a mixture of (2,4-cis and trans)-is oannonacin were also isolated for the first time from this species.