2-Chloro-1-methylpyridinium iodide (0.47 g, 1.84 mmol), DIEA (0.44 mL, 2.5 mmol) and 4-p-tolylthiazol-2-amine (0.24 g, 1.23 mmol) were added to a solution of 2-(tert-butoxycarbonylamino)thiazole-5-carboxylic acid (0.30 g, 1.23 mmol) in DMF (5 mL). The resulting solution was stirred at RT until completion of the reaction. Then the reaction mixture was diluted with AcOEt, washed with water, dried with Na2SO4 and concentrated. The crude product was purified by column (100% AcOEt), yielding tert-butyl 5-(4-p-tolylthiazol-2-ylcarbamoyl)thiazol-2-ylcarbamate (80 mg, 17%) as a solid.
