D. palustris is the only native member of the Thymelaeaceae
in the province of Quebec, Canada.3 This family is noticeable
for its daphnane-type diterpenoid orthoesters, which among
other biological effects are potent cytotoxic agents.13 Such
diterpenoid compounds have been isolated from the related
species D. occidentalis, along with cytotoxic lignans and
coumarins.14 The chemical composition of D. palustris has
not been extensively studied, with only five phenolic glycosides15
and three triglycerides16 reported in the literature. The
bioassay-guided fractionation of a cytotoxic extract of this plant
led to the isolation of a new group of sulfur-containing
secondary metabolites, named dirchromones (1−8, Figure 1).
This study presents the isolation, structure elucidation,
cytotoxicity, and antibiotic activity of these new compounds