32 Hura crepitans L.樹液の魚毒性物質

抄録

A piscicidal constituent was isolated from the milky sap of Hura crepitans, and named huratoxin. Huratoxin (I), resinous matter, [α]^<28°>_D+55.1°, TLm (24h.) to Oryzias laptipes 0.0014ppm, absorbed three molar equivalents of hydrogen to give hexa-hydrohuratoxin (II). Diacetates (III) and (IV) were obtained from I and II, respectively. From the spectral analysis of I, II, III and IV it is suggested that I contains an isopropenyl, a secondary methyl, a primary hydroxyl, a secondary hydroxyl, a tertiary hydroxyl and partial structure (c). The spectral data of triacetate (VI) of the octahydro-derivative (V) and lithium-ammonia reduction product (VII) of IV indicated partial structure (d) in I. Periodic acid oxidation of V afforded an α-methyl-α,β-unsaturated aldehyde ketone (VIII). This suggests that partial structure (d) can be expanded to (e). Formation of bromohydrins (IX) and (X) suggests partial structure (f). Ozonolysis of III with two molar equivalents of ozone gave formaldehyde, n-decanal and a keto-enal (XI). The M^+ peak in the high resolution mass spectrum of XI assigned C_<27>H_<30>O_<12> to XI, accordingly C_<34>H_<48>O_8 to I. Hydrolysis of IV afforded myristic acid. This expands partial structure (c) to (g), and shows that the C_<14>-straight chain is bonded through oxygen to the C_<20>-moiety. Thus partial structures shown in Fig.3 were derived.