An efficient synthesis of 2,4-substituted [1,8]naphthyridines from 3-(2-Amino-5-methylpyridin-3-yl)-1-arylprop-2-yn-1-ones

3-(2-Amino-5-methylpyridin-3-yl)-1-arylprop-2-yn-1-ones 2, readily available through Pd-catalyzed carbonylative coupling of 5-methyl-3-[2-(trimethylsilyl)ethynyl]pyridine-2-ylamine (1) with aryl iodides in the presence of carbon monoxide, undergo a domino conjugate addition/annulation reaction to give 4-hetero-substituted 2-aryl[1,8]naphthyridines 3 in high yields