Synthesis of 2-Aryl-5-Nitropyridines by Three-Component Ring Transformation of 3,5-Dinitro-2-Pyridone

2‐Arylated‐5‐nitropyridines were efficiently synthesized by a three‐component ring transformation of 3,5‐dinitro‐2‐pyridone with aromatic ketones in the presence of ammonium acetate, in which the dinitropyridone serves as a synthetic equivalent of an unstable nitromalonaldehyde. Although a 2,8‐diazabicyclo[3.3.1]non‐3‐ene derivative was also formed as a byproduct, it was converted into nitropyridines under the reaction conditions, heating in the presence of ammonium acetate. This experimental fact implies that the former compound is a kinetically controlled product and the latter is a thermodynamically controlled product because of the aromatization. This method is applicable to various kinds of aryl and (hetero)aryl ketones to afford the corresponding (hetero)arylated pyridines in good to excellent yields. Three's a transformation: 2‐Arylated‐5‐nitropyridines were efficiently synthesized by a three‐component ring transformation of 3,5‐dinitro‐2‐pyridone with aromatic ketones in the presence of ammonium acetate. This method is applicable to various kinds of (hetero)aryl ketones to afford the corresponding (hetero)arylated pyridines in good to excellent yields.