Ligularia clivorum

Clivorine, the alkaloid of Ligularia clivorum Maxim., was earlier shown to be a pyrrolizidine alkaloid whose basic constituent is otonecine (64). The acid component is a hydroxydicarboxylic acid which readily lactonises, on attempted isolation, to clivonecic acid (65). The structure of this acid has now been firmly established on the basis of chemical and spectroscopic evidence, and its stereochemistry has also been discussed. The present proposal" is that clivonecic acid has the S-configuration at C-2 since the o.r.d. spectrum of tetrahydroclivonecic acid exhibits a positive Cotton effect, in agreement with the modified octant rule. ... 

Aside from its occurrence in Ligularia clivorum Maxim., clivorine has recently been isolated from L. elegans Cass. [L. macrophylla (Ledeb.) DC], L. dentata (A. Gray) Hara, and L. brachyphylla Hand.-Mazz. These three species were also shown to contain a new, non-crystalline alkaloid, ligularine, while L dentata and L. brachyphylla contain another new alkaloid, ligudentine, which is also amorphous. 

Klasek, A., P. Vrublovsky, and F. Santa vy Isolation of Pyrrolizidine Alkaloids from the Plants Senecio rivularis D. C. and Ligularia clivorum Maxim. Collect. Czech. Chem. Commun. 32, 2512 (1967). 

Ligularia brachyphylla Hand.-Mazz. L. clivorum Maxim. 

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