Sprayed water rewires aniline into pyridine: a green skeletal editing breakthrough

Water microdroplets enable a reagent-free conversion of aniline to pyridine via a rapid skeletal rearrangement at the air–water interface, suggesting a green route to heterocycles. The proposed mechanism starts with hydroxyl-radical initiation, forms a seven-membered lactone, eliminates CO to revert to a six-membered ring, and oxidizes to aromatic pyridine. The team also converted pharmaceutically relevant anilines to niacin, nicotinamide and isoniazid, highlighting green potential while noting scalability and isolated-yield challenges.