Citral was reacted with emodin [3] in the presence of pyridine to give
(+/-)-ploiariquinone A [1]. Oxymercuration of 1 using Hg(OAc)(2) foll
owed by reduction of the mercurial intermediate by NaBH4 yielded a com
plex mixture from which (+/-)-ploiariquinone B [2] was isolated. Ploia
riquinones A and B have been isolated previously from Ploiarium altern
ifolium.