Faculty of Environmental Studies of Nagasaki University, 1–14, Bunkyo‐machi, Nagasaki 852–8521, Japan
Abstract:
New 2‐pyrone derivatives, dialkyl 3‐cyano‐6‐phenyl‐2‐oxo‐2H‐pyran‐4‐ylmalonates and alkyl 3‐cyano‐6‐phenyl‐2‐oxo‐2H‐pyran‐4‐ylacetates, which were easily prepared by the reaction of 6‐aryl‐4‐methyl‐sulfanyl‐2‐oxo‐2H‐pyran‐3‐carbonitriles with active methylene compounds in the presence of potassium carbonate, show fluorescence emission radiation. The light‐emitting region of dimethyl 3‐cyano‐6‐(4‐N,N‐dimethylamino)styryl‐2‐oxo‐2H‐pyran‐4‐ylmalonate ( 7h ) was 620 nm in dichloromethane, making this compound a typical red fluorescent compound. Methyl 8‐hydroxy‐6‐methyl‐1‐oxo‐3‐phenyl‐1H‐pyrano‐3,4‐c]pyridine‐5‐carboxylate deriv‐atives also showed fluorescence in the solid state. This is the first example of fluorescence in fused 2‐pyrone derivatives.
