Of inumakilactone

On catalytic hydrogenation with Pt02 inumakilactone A (28) yielded the corresponding dihydro derivative 113 [40]. In contrast, the C ring double bond of inumakilactone B (31) was unaffected when this dilactone was catalytically hydrogenated with Pd-C [44]. 

Wih respect to the insecticide activity, Podocarpus macrophyllus is widely known in Japan for its resistance to termite attack. Saeki disclosed in 1970 that the termiticidal activity is entirely due to inumakilactone A (28) and another unidentified compound of similar structure, the former being more active [70]. This second compound was later reported to be nagilactone D (4). 

Thus, to confirm the location of the two hydroxyl groups in inumakilactone A (28), this compound was selectively acetylated, and its diacetate selectively saponificated. The thus obtained 15- and 3-monoacetates were oxidized to the corresponding ketones with Jones reagent (Scheme 3) [40],... 

Structure of the further norditerpenoids of Podocarpus macrophyllus. Inumakilactone A glucoside, a plant growth inhibitor and inumakilactone E. Hayashi, T. Kakisawa, H. Ito, S. Chen, Y.P. Hsu, H-Y. Tetrahedron Lett. 1972,33,3385-3388. 

Crystal and molecular structure of the bisnorditerpenoid inumakilactone. Godfrey, J.E. Waters, J.M. Aust. J. Chem. 1975,28,745-753. 

Higher plants and some microorganisms produce a number of diterpene lactones such as podolactones A-E, ponolactones A and its glucoside, inumakilactones A, its glucoside, B and E, nagi-latone C, momilactones A-C, and sellowin A, many of which are inhibitory to the growth of plants (Table 5). 

Ponolactone A and its glucoside are inhibitors of expansion and mitosis in plant cells. Ponolactone A was isolated from Podocarpus nakai and shown to have the structure (25) by a detailed study of its n.m.r. spectrum, utilizing the nuclear Overhauser effect. The C-14 epimer was prepared from the C-7 acetate of nagilactone. Inumakilactone B was isolated" from Podocarpus macrophyllus and shown by a combination of chemical and spectroscopic evidence to have the structure (26). Inumakilactone C was tentatively assigned structure (27) on the basis of spectroscopic evidence. 

The structures of a number of norditerpenoid lactones from Podocarpus species have been revised as a result of some X-ray analyses. Inumakilactone A (46) has... 

Analogously there exist in Nature various oxidatively degraded lower terpenoids and examples of nor- and bisnor-diterpenoids are afforded by the inumakilactones [87] and the nagilactones [88]. Interesting examples of what... 

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