反应详情

To a solution of 4-bromopyridine-2-carboxylic acid (0.5 g, 2.5 mmol, Apollo Scientific) in a mixture of ethyl acetate (15 mL) and methanol (1.5 mL), was added dropwise a solution of trimethylsilyldiazomethane (3.7 mL, 2 M in diethyl ether, 7.4 mmol), at about 0° C. After the addition was complete the temperature was raised to rt and the mixture stirred for about another 1.5 h at rt. The resulting mixture was concentrated in vacuo and diethyl ether (25 mL) was added to the residue. The resulting mixture was filtered and concentrated in vacuo. The residue was purified by column chromatography (SiO2, diethyl ether/hexanes 1:1) to give methyl 4-bromopyridine-2-carboxylate (0.39 g, 1.8 mmol, 73%) as a pale yellow solid: 1H-NMR (CDCl3, Bruker 400 MHz) δ 4.03 (3H, s), 7.67 (1H, dd, J=5.0, 1.6 Hz), 8.31 (1H, d, J=1.6 Hz), 8.57 (1H, d, J=5.0 Hz).

1. customat about 0° C
2. additionAfter the addition
3. concentrationThe resulting mixture was concentrated in vacuo and diethyl ether (25 mL)
4. additionwas added to the residue
5. filtrationThe resulting mixture was filtered
6. concentrationconcentrated in vacuo
7. customThe residue was purified by column chromatography (SiO2, diethyl ether/hexanes 1:1)