Alkaloids containing an indolizidine unit

Three isomeric bases solanogantine, solanogantamine and isosolanogantamine have been found in 5. giganteum leaves They are formulated as (61), (62) and (63) respectively, on spectral evidence from the bases and their derivatives (Pakrashi et al.. Tetrahedron Letters, 1977, 645, 814 J. Indian chem. Soc., 1978, 55, 1109). 

Solanopubamine, from the aerial parts of 5. pubesaens, has been investigated spectroscopically. It is isomeric with solanogantamine (62) and since its structure and stereochemistry have been settled (64) it follows that the C-25 methyl group in solanogantamine must be 3 (Kaneko et al., Phytochem., 1985, 1369). The indolizidine group 

An antimicrobial base solacasine has been found in the flowers of S. pseudocapsiaum. In its mass spectrum it showed peaks at m/z 56 and 82, associated with 33-amino-steroids. An azomethine linkage is responsible for its ir-absorption at 1660 cm. on reduction (NaBHi,) a primarysecondary diamine structure results, convertible into a trimethyl derivative on Eschweiler-Clark methylation. Structure (65) has been advanced and confirmed by the formation of dihydrosolacasine by methanolysis of solano-capsine (L. A. Mitscher et al., Experientia, 1976, 415). 

Solanoforthine, a similarly-structured base from S. sea-fovthianwn is formulated as (66) largely on spectral evidence (Pakrashi et at.. Tetrahedron, 1977, 1371). 

---