n-Nitric Oxide Synthase Inhibitor

Significance

N-Indolylamidines, such as G, are inhibitors of neuronal nitric oxide synthase (nNOS) and 5-HT_1D/1B receptors. They are of interest for the treatment of migraine headaches. A key step in an enantioselective synthesis of the 3-pyrrolidinylindole core F is an organocatalytic asymmetric conjugate addition of 5-bromoindole (A) to an ­iminium ion generated from condensation of the MacMillan imidazolidinone C with the 4-amino-2-butenal derivative B.