To a mixture of 2-[(3-methyl-thiophen-2-ylmethyl)-amino]-thiazol-4-one (21.7 mg, 0.10 mmol), AcONa (160 mg, 1.95 mmol) (see Example 5), and 6-formyl-[1,5]naphthyridine-3-carbonitrile (22.0 mg, 0.12 mmol) (see Example 11) in a sealed tube was added AcOH (0.3 mL). The reaction mixture was heated to 100° C. (oil bath) for 1.5 hrs. The reaction mixture was then cooled to r.t. and triturated with water. The solid was collected by filtration and washed with water, AcOEt and ether to give 6-{2-[(3-methyl-thiophen-2-ylmethyl)-amino]-4-oxo-4H-thiazol-5-ylidenemethyl}-[1,5]naphthyridine-3-carbonitrile as a light brown solid (14.0 mg, 35.8%). HR-ES (+) m/e calcd for C19H13N5OS2 (M+H)+ 414.0454. found 414.0452.
