The synthesis of various oligopyridines possessing a carboxylate
and at least one bromoethyl group is reported. The bipyridine and
terpyridine cores were constructed in good yields via a Stille cross-coupling,
starting from bromopicolines and ethyl bromopicolinate. The bromomethyl
function was obtained by free radical bromination using NBS in benzene
or bromine in benzene/water biphasic mixture. The building
of two model podands by nucleophilic displacement of benzylic bromine
by an amine or by a phenol group is described.
Stille reaction - bipyridines - terpyridines - carboxylate - halogenation