An efficient synthesis of novel benzo[b]pyrido[3′,2′:4,5]thieno[2,3-e][1,6]naphthy-ridine-8-ones

Abstract

Abstract An efficient method for the synthesis of novel benzo[b]pyrido[3′,2′:4,5] thieno[2,3-e][1,6] naphthyridine-8-one derivatives has been developed using a Pictet–Spengler reaction between 4-(3-aminothieno[2,3-b]pyridin-2-yl)quinoline-2-ones, which could be obtained from the alkylation of 4-bromomethylquinoline-2-ones with 3-cyanopyridine-2-thione followed by a Thorpe–Ziegler isomerization, and aromatic aldehydes under p -TsOH as catalysis in good yields.