Synthesis
General procedure for the synthesis of methyl 4-nitropyridinecarboxylate from methanol and 4-nitro-2-pyridinecarboxylic acid: firstly, esterification of 4-nitro-2-pyridinecarboxylic acid was carried out in anhydrous methanol by reacting with concentrated sulfuric acid as a catalyst at 25 °C for 18 h. Methyl 4-nitropyridinecarboxylate (1f) was obtained in 65% yield. Subsequently, a mixed solution of methyl 4-nitro-2-pyridinecarboxylate (1f) (1.0 g, 6.62 mmol) with acetone (0.195 mL, 2.65 mmol) in DME (5 mL) was slowly added dropwise to a stirred NaH suspension (60% oil suspension, 0.5 g, 13.23 mmol in DME 5 mL), and the reaction was carried out at room temperature under argon protection. The reaction was carried out at room temperature under argon protection. The reaction mixture was stirred at 30 °C for 2 h or 18 h and then refluxed for 2 h, during which no gas escape was observed. The feedstock was recovered during reprocessing.
References
[1] Tetrahedron, 2014, vol. 70, # 45, p. 8520 - 8531
