15.00 g (28.84 mmol) of 2-amino-6-({(2-(4-chlorophenyl)-1,3-thiazol-4-yl)methyl}sulfanyl)-4-(4-(2-hydroxyethoxy)phenyl)pyridine-3,5-dicarbonitrile (Example 1A) were initially charged in 200 ml of acetonitrile, and 6.76 g (57.69 mmol) of isopentyl nitrite and 7.76 g (57.69 mmol) of copper(II) chloride were added. The mixture was stirred at 70° C. for 6 h. After cooling to RT, 750 ml of 1N hydrochloric acid were added and the mixture was stirred for 30 min. The aqueous phase was extracted three times with ethyl acetate. The combined organic phases were dried over sodium sulfate. After removal of the solvent, the crude product was purified by column chromatography on silica gel (mobile phase: toluene/ethyl acetate 4:1). This gave 10.8 g (69% of theory, purity 90%) of the desired target compound. For further purification, the product may, if appropriate, be triturated with diethyl ether.
