Strategic Approach to 8-Azacoumarins.

8-Azacoumarins have emerged as a promising class of compounds but are rarely explored due to challenging access. A novel, general, and practical method is provided for this class of compounds. The key lactonization step employs trans-acrylic acid attached pyridine N-oxides as the starting material, with acetic anhydride as both the activation agent and the solvent. Multiple transformations were involved in this reaction, including conjugate addition, nucleophilic aromatic substitution, and elimination. These studies provide the basis for access to 8-azacoumarins, enabling future work including the discovery and development of novel coumarin-type drugs, fluorescent probes, photolabile protecting groups, and other active molecules.