Diethyl pyridine-2,6-dicarboxylate (4.70g, 21.1mmol) was dissolved into a mixture of
ethanol (50mL) and 1,4-dioxane (100mL), then NaOH (0.86g, 21.0mmol) was added.
The mixture was heated to reflux for 1.5 hours, and then 1M HCl aqueous solution
(21mL) was added. After removal of the solvents, the residue was applied to column
chromatography with CH2Cl2/ethanol (1:1) as eluents to afford 2 as white powder
(2.97g, 15.2mmol, yield = 72%). 1
H-NMR (400MHz, CDCl3) δ ppm 8.41 (d, J = 7.74
Hz, 1H), 8.37 (d, J = 7.80 Hz, 1H), 8.13 (t, J = 7.77, 7.77 Hz, 1H), 4.50 (q, J = 7.13,
7.13, 7.13 Hz, 2H), 1.46 (t, J = 7.13, 7.13 Hz, 3H). ESI MS: m/z = 196.1 [M+H]+
,
218.1 [M+Na]+
.
