4-Methoxy-pyridine-2,6-dicarboxylic acid monomethyl ester

Chelidamic acid (0.8 g, 4.4 mmol) was refluxed in methanol (50 mL) in presence of sulfuric acid (1 mL) for 4 days, and the completion of the reaction was checked by mass spectrometry. The solvent was removed, the crude product dissolved in water and neutralized by saturated NaHCO3 solution. It was extracted by dichloromethane, the organic phase dried over Na2S2O4 and the solvent evaporated to give 4-methoxy-pyridine-2,6-dicarboxylic acid dimethyl ester (0.6 g, 61%)^[1].

[1] Gassner, A.-L., Duhot, C., Bünzli, J.-C. G., & Chauvin, A.-S. (2008). Remarkable Tuning of the Photophysical Properties of Bifunctional Lanthanide tris(Dipicolinates) and its Consequence on the Design of Bioprobes. Inorganic Chemistry, 47 17, 7802–7812. https://doi.org/10.1021/ic800842f