Under argon and at 0° C., 10 min apart two portions of in total 350 mg (purity 82%, 1.10 mmol) of 4-chloro-2-(5-methoxy-2-oxo-1,2-dihydropyridin-4-yl)benzonitrile were added to a suspension of 53 mg (1.32 mmol, 1.2 eq.) of sodium hydride (60% in mineral oil) in 2.1 ml of dimethylformamide. The reaction mixture was stirred at RT for 60 min and then cooled back to 0° C., 245 mg (purity 90%, 1.32 mmol, 1.2 eq.) of ethyl 2-chloro-2-ethoxyacetate were added and the mixture was stirred at RT for 2 h. This batch together with an analogous test batch was combined with 50 mg (purity 82%, 0.16 mmol) of 4-chloro-2-(5-methoxy-2-oxo-1,2-dihydropyridin-4-yl)benzonitrile. After addition of 20 ml of water and phase separation, the aqueous phase was extracted twice with ethyl acetate. The combined organic phases were dried (sodium sulphate), filtered and concentrated under reduced pressure. The crude product was purified by flash chromatography (IR-50Si, petroleum ether/ethyl acetate 15-50%). Yield: 277 mg (55% of theory based on in total 1.26 mmol of 4-chloro-2-(5-methoxy-2-oxo-1,2-dihydropyridin-4-yl)benzonitrile employed)
