Callosine, a 3-alkyl-substituted pyrrolizidine alkaloid from senecio callosus
Two collections of Senecio callosus from different regions of Mexico contained a structural diversity of pyrrolizidine alkaloids (PAs), which may contribute to the easy adaptation of this species. In addition to some known compounds, two new PAs (1 and 2) were isolated, and their structures were established by chemical transformations and spectroscopic studies.
Instituto de Quimica, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, Coyoacan 04510, D.F., Mexico, and Instituto de Biologia, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universi.
AL
Perez-Castorena
A
Arciniegas
RP
Alonso
JL
Villasenor
Romo de Vivar A