Pyrrolizidine alkaloid biosynthesis; incorporation of 13C-labelled putrescines into retronecine
Abstract
[1,4-13C2]- and [2,3-13C2]-Putrescine are incorporated into retronecine (2) in Senecio isatideus plants, giving labelling patterns consistent with the formation of a C4–N–C4 intermediate in retronecine biosynthesis.