Pyrrolizidine alkaloids from Heliotropium rotundifolium.

Heliotropium rotundifolium was shown to contain, in addition to the previously isolated europine [1], three other alkaloids: heliotrine [2], lasiocarpine [3], and a new alkaloid identified as 5'-acetyleuropine [4]. The alkaloids were isolated by dccc and the structures established by spectroscopic means (1H and 1H- 13CHETCOR nmr and ms), physical properties (melting points and/or optical rotations), comparison with authentic samples, or by semi-synthesis.