An efficient synthesis of indol-3-yl benzonaphthyridines via copper(II) triflate-catalyzed heteroannulation

An efficient and convenient method for the synthesis of indol-3-yl benzo[b][1,6]- and benzo[c][2,7]naphthyridines via copper(II) triflate-catalyzed heteroannulation is reported. This method gives new analogues of indole containing benzonaphthyridines from easily accessible starting materials. This reaction proceeds under mild conditions. (C) 2013 Elsevier Ltd. All rights reserved.