Step 1: In a reaction flask containing a mixed solution of dichloromethane (1300 mL) and water (1100 mL) with 4-cyanopyridine (52 g, 0.5 mol), ammonium persulfate ((NH4)2S2O8) (170 g, 0.75 mol), silver nitrate (6.8 g, 0.04 mol), and aqueous sulfuric acid (40 mL, prepared from 98 mL of concentrated sulfuric acid (prepared with 400 mL of water). Subsequently, a solution of 3-oxobutanoic acid (110 g, 1.25 mol) in dichloromethane (100 mL) was added slowly and dropwise while keeping the reaction mixture at reflux. After refluxing the reaction for 2 h, the reaction mixture was alkalized with sodium carbonate powder to pH 8-9. The reaction mixture was filtered and the filtrate was extracted with dichloromethane (500 mL x 3). The organic phases were combined, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The residue was recrystallized by ethanol to give 2-acetylisonicotinonitrile (52.0 g, 71.9% yield).
