Tautomerism in heteroaromatic compounds involves the movement of an atom or group from one position on the ring to another, typically a proton (prototropy) and usually via an intermolecular mechanism.(1, 2) Any atom or group can be part of a tautomeric equilibrium as long as there is sufficient energy to drive the process.(3) The possibility of chlorotropy has been considered.(4) To date, the only known example of this process is the equilibrium ...
