Rearrangement of 7-Aryloxazolo[5,4-]pyridines to Benzo[][1,7]naphthyridine-4(3)-ones and Thieno[3,2-][1,7]naphthyridine-6(7)-ones.

In this work, we describe the development of the rearrangement for 7-aryl-substituted oxazolo[5,4-]pyridines treated with aluminum chloride into synthetically hard-to-reach benzo[][1,7]naphthyridinones. The discovered rearrangement is applied to a variety of electron-rich (hetero)arene substrates. It offers the advantages of mild conditions (90 °C temperature), fast reaction rates (<4 h), compatibility with air moisture, and the use of inexpensive commercial reagents.