Shiromodiol

A number of sesquiterpenes have been demonstrated to have pronounced biological activity ( ) among the non-volatile compounds the sesquiterpene lactones are best known (M) but other oxygenated sesquiterpenes are also known to be active. For example, the role of gossypol, a dimeric sesquiterpene and structurally related compounds has been investigated (21,22). The oxygenated sesquiterpenes, shiromodiol monoacetate and diacetate, from Parabenzoin trilobum (=Lindera triloba Blume) possess potent anti feeding activity toward Spodoptera litura larvae (85). 

The X-ray analysis of the silver nitrate adduct of costunolide clearly shows that the molecule exists as the conformer (204) with the methyl groups in a syn relationship and the double bonds mutually perpendicular. The same features have also been found by the A -ray analyses of the pregeijerene (205)-silver nitrate complex and heavy-atom derivatives of elephantol (206) and shiromodiol (207). ... 

Two interesting results have been obtained in the thermolyses of shiromodiol acetate (226) ° and the germacratriene epoxide (227). Both give rise to the same type of rearrangement products, viz., (228) and (229), and (230) and (231) respectively, and it is suggested that formation of (228) and (230) can be rationalised in terms of a double electrocyclic process via (232) as shown. These transformations may be significant in terms of the genesis of carabrone (233). 

Other antifeedants such as shiromodiol diacetate (50) have been isolated from Parabenzoin trilobum (syn. Lind-era, Lauraceae). These compounds are active against feeding by polyphagous and oligophagous insects at the 0.05-0.1% level in artificial diets (Mabry and Gill, 1979 Munakata, 1977). 

Shiromodiol acetate, T20.17 Pulchellin A, T24.9 Aeginetinic acid, T 43.10 PGF20, precursor, Y"14.8 C15H24S... 

A. niger also converted shiromodiol diacetate (136) isolated from Neolitsea sericea to 2p hydroxy derivative (137) (Nozaki et al., 1996) (Figure 20.45). 

FIGURE 20.45 Biotransformation of shiromodiol diacetate (136) hy Aspergillus niger. 

Nozaki, H., K. Asano, K. Hayashi, M. Tanaka, A. Masuo, and D. Takaoka, 1996. Biotransformation of shiromodiol diacetate and myli-4(15)-en-9-one hy Aspergillus niger IFO 4407. Proceedings of 40th TEAC, pp. 108-110. 

Setoclavine, K17 Seychellene, T27 Shellolic acid, T29 Shikimic acid, A26 Shionone, T42 Shiromodiol, T20 Showdomycin, C4 Shyobunone, T22 Siccanin, T32 Silanes, Z1... 

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