Synthesis
General procedure for the synthesis of ethyl 4-ethoxy-2-pyridinecarboxylate from 4-chloropyridine-2-carboxylic acid and ethanol: 4-chloropyridine-2-carboxylic acid (3.0 g, 19.04 mmol) was dissolved in ethanol (100 mL) and concentrated sulfuric acid (5 mL) was added as a catalyst. The reaction mixture was stirred under reflux conditions for 48 hours. After completion of the reaction, the mixture was cooled to room temperature and neutralized with 1N NaOH solution to pH 8~9. Subsequently, the reaction mixture was extracted with dichloromethane (3 x 100 mL), the organic phases were combined and concentrated to afford ethyl 4-ethoxy-2-pyridinecarboxylate (3.44 g, 93% yield).
References
[1] Patent: WO2007/16525, 2007, A2. Location in patent: Page/Page column 54
[2] Patent: US2013/281396, 2013, A1. Location in patent: Paragraph 0319-0320
[3] Patent: WO2013/164769, 2013, A1. Location in patent: Page/Page column 46-47
