Nasimaluns A and B: neo-clerodane diterpenoids from barringtonia racemosa

An ethanolic extract of the roots of Barringtonia racemosa afforded two novel neo-clerodane-type diterpenoids, methyl-15, 16-epoxy-12-oxo-3,13(16),14-neo-clerodatrien-18, 19-olide-17-carboxylate (nasimalun A, 1) and dimethyl-15,16-epoxy-3, 13(16),14-neo-clerodatrien-17,18-dicarboxylate (17-carboxymethylhardwickiic acid methyl ester, nasimalun B, 2) by NMR and MS analyses and by comparison of their spectral data with related compunds. The relative stereochemistry of the asymmetric centers in 1 and 2 was determined by selective 1D NOESY experiments.