Accessing Quinoxalines by Ring-Opening/Cyclization/Detosylation/Aromatization of Activated Aziridines with 2-Bromoanilines: Synthesis of Tyrphostin AG 1296

Abstract

Substituted 2-arylquinoxalines have been synthesized by an unprecedented CuI-catalyzed ring-opening/cyclization reaction followed by detosylation/aromatization of activated aziridines with 2-bromoanilines. The transformation efficiently accommodates a wide range of aziridines and 2-bromoanilines to afford the desired quinoxaline frameworks in excellent yields (up to 86 %) as single regioisomers. The methodology has also been conveniently applied to the synthesis of tyrphostin AG 1296, a PDGF-receptor tyrosine kinase inhibitor.