A facile synthesis of 4-azaisoindoles and their transformation into novel pyrrole-fused 2-pyridones

Abstract

We describe herein a novel, efficient and practical synthetic approach to access pyrrolo[3,4-b]pyridines from dihydropyridones in three steps, in which a pyrrole unit is generated from a dihydropyridone using TosMIC reagent. Protection of the resulting pyrrole, Grignard addition followed by oxidative aromatization afford substituted pyrrolo[3,4-b]pyridines. These underutilized structures are subsequently transformed to novel pyrrole-fused 2-pyridones via N -alkylation and then oxidation. • Novel method to generate pyrrolopyridines. • Various R groups on pyrrolopyridines. • Novel salts from pyrrolopyridines. • Novel pyrrole-fused 2-pyridones. • Various groups on the pyrrole-fused 2-pyridones.