Extracts of Sesbania drummondii seed have yielded three new glutarimide tumor inhibitors which are markedly active in the PS leukemia (in uiuo) system and in the KB cell culture system. Structures of sesbanimide A, sesbanimide B, sesbanimide C, acetylation products of the sesbanimides and five compounds obtained by hydrogenating sesbanimide A under mild conditions have now been established using high-field 'H NMR, 13C NMR and mass spectral correlations. Treatment of sesbanimide A diacetate with sodium bicarbonate in aqueous methanol gives rapid elimination of acetic acid and two subsequent products derived via solvolysis of the glutarimide ring.