GREENHEART ALKALOIDS
1963
Hearst, Peter J.
It is commonly believed that the resistance of the tropical wood greenheart (Ocotea rodiaei) to marine borer attack is due to the pressence of the toxic alkaloid 'bebeerine,' and that this alkaloid is the same as chonrodendrine (1), whose structure is known. The latter alkaloid could not be obtained from greenheart. Rodiasine dimethiodide, which was isolated, apparently is the first pure alkaloid obtained from greenheart. By gradient elution chromatography and subsequent fractional crystallization, eight alkaloid hydro chlorides were isolated from the ether-soluble alkaloids of greenheart bark. The alkaloids fall into two groups. One group consists of four bisbenzylisoquinoline alkaloids of the oxyacanthine series: ocoteamine (XV) and otocamine (XVII), which are, respectively, one of the methyl ethers and the dimethyl ether of trilobamine; and demerarine and ocodemerine, which appear to be the corresponding diasterioisomers. The other group consists of four alkaloids which have prop erties of bisbenzylisoquinoline alkaloids with one diphenyl ether linkage: rodiasine, isorodia sine, and norrodiasine, all have the same skeletal structure; and dirosine, which has a different skeletal structure. All the alkaloids are quite toxic to Teredo but less toxic to Limnoria, and when impregnated into pine panels, they prevent Teredo attack and greatly reduce Limnoria attack. The alkaloids may therefore be the chief factor in the resistance of greenheart to the former species of marine borer but may be a less important factor in its resistance to the latter species.
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