Example 3 Synthesis of 2-amino-4-methylpyridine-3-carbonitrile (7): a mixture of compound (5) and compound (6) (97 g) obtained in the previous experiment (fraction #2) was dissolved in 1 L of ethanol. Anhydrous ammonia was passed into the solution through a sintered filter candle for 15 min at room temperature. Subsequently, the reaction mixture was heated to reflux and maintained for 2 hours. Upon completion of the reaction, the mixture was slowly poured into 2 L of water. The product in the aqueous phase was extracted with 300 mL of ether in three fractions. The organic phase was combined, dried with anhydrous magnesium sulfate, filtered and concentrated to dryness under reduced pressure. Addition of ether to the residue precipitated a solid, which was dried by filtration to give 49 g (39.0% yield) of the target product (7), calculated on the basis of 100 g of isopropylidenemalonononitrile (4) (taking into account recovered material). Product characterization: melting point 148-151 °C; 1H NMR (CDCl3) δ: 2.4 (s, 3H), 5.4 (bs, 2H), 6.57 (d, 1H), 8.07 (d, 1H).
