A new class of protein kinase C (PKC) inhibitors is described. These i
nhibitors were derived from the familiar bis-indolyl maleimide series
of inhibitors through a structural rearrangement involving transfer of
one aryl ring from the maleimide moiety to the C-2 position of the in
dole ring remaining attached to that moiety. The resulting compounds a
re among the most potent known inhibitors of PKC and also show good se
lectivity for PKC in relation to other kinases. The lead compound in t
his series possesses antitumor activity in several in vitro and in viv
o models.