Numerous 2-methoxy-6-n-alkyl-1,4-benzoquinones with interesting biolog
ical activities have been found as constituents of plants and plant se
eds. The most prominent is primin, the n-pentyl derivative, which is s
tored in trichomes on leaves and stems of Primula obconica and is resp
onsible for primrose dermatitis. The biosynthesis of primin was studie
d by feeding experiments with radioactively labelled precursors and un
labelled homologues.