Step 1: A mixture of malononitrile (0.33 g, 5 mmol) and trimethyl orthoformate (0.64 g, 6 mmol) was stirred at 80 °C for 1 hour. The reaction mixture was cooled to room temperature and then a methanol (10 mL) solution of N,N-dimethylformamide dicarboxylate (6 mmol) was added with stirring. The reaction mixture was refluxed for 30 minutes. After cooling, the resulting precipitate was filtered, dried and recrystallized from methanol to give pure 1,1-dicyano-2-methoxy-4-dimethylamino-1,3-butadiene as light red crystals. Yield: 76%, melting point: 130-131 °C. [1] Step 2: Acetic acid (10 mL) was added to the intermediate from the previous step (0.53 g, 3 mmol), and the temperature was increased to 125 °C until the reaction was complete, as monitored by TLC. Excess acetic acid was evaporated under vacuum to obtain crude 4-Methoxy-2-oxo-1,2-dihydro-pyridine-3-carbonitrile. The crude product was recrystallized from methanol to give white crystals, which were the target product.
N-Demethylricinine is a demethylated metabolite of Ricinine (R495550), an alkaloid extract from the castor-oil plant (Ricinus communalis). N-Demethylricinine is an impurity in the production of Gime
racil.
