The isolation and structure determination of the alkaloid ent-norsecurinine (4) from Phyllanthus niruri L. is described. The structure and absolute stereochemistry have been confirmed by an X-ray analysis of ent-norsecurinine hydrochloride.
A new norditerpenoid alkaloid designated as ajadinine [1] has been isolated from the seeds of Delphinium ajacis. Its structure [1] was established from physical and spectroscopic data. The known alkaloids desoline, delcosine, and gigactonine have also been obtained from this same source. Complete and unambiguous nmr assignments for the lycoctoninetype norditerpenoid alkaloids 14-deacetylajadine [2], ajacine [3], delcosine [4], and ambiguine [5] are also presented in this work. Assignments for the aromatic protons of the C-18 N-acetyl anthranilic acid ester group were made by selective INEPT nmr experiments.
From the aerial parts of Consolida oliveriana (DC) Schröd. a new norditerpenoid alkaloid consolidine (2) has been isolated, in addition to the known alkaloids pubescenine (1), gigactonine, and delsoline and the diterpenoid alkaloid ajaconine (4). The structure of alkaloid 2 was established on the basis of its physical and spectroscopic data including detailed NMR studies. A detailed NMR study on ajaconine (4) resulted in the revision of 11 13C chemical shift assignments.
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