反应详情

To a round bottom flask containing 2-bromo-5-pyridinecarboxylic acid (10.0 g, 49 mmol) in DCM (500 mL) was added oxalyl bromide (7.4 mL) and 5 drops of DMF. After some gas evolution, the reaction mixture was stirred at reflux ca 6 h, then cooled to rt and heptane 100 mL was added, followed by concentration of the mixture. The mixture was then suspended in THF 400 mL, cooled to 0° C. t-BuOK (5.8 g, 52 mmol) was then added and the r×n allowed to warm to rt and stirred for 2 h. The mixture poured into EtOAc, washed with 1 N NaOH, water, brine, dried MgSO4 filtered and concentrated. The residue was purified by silica gel chromatography Biotage 40S Heptane EtOAc 0-80% 3 L to afford the title compound 4.2 g (36%) of as a white solid. 1H NMR (400 MHz, DMSO-d6) □ ppm 8.78-8.86 (1H, m), 8.14 (1H, dd, J=8.4, 2.4 Hz), 7.81 (1H d, J=8.4 Hz), 1.56 (9H, s).

1. temperatureat reflux ca 6 h
2. additionwas then added
3. temperatureto warm to rt
4. stirringstirred for 2 h
5. washwashed with 1 N NaOH, water, brine, dried MgSO4
6. filtrationfiltered
7. concentrationconcentrated
8. customThe residue was purified by silica gel chromatography Biotage 40S Heptane EtOAc 0-80% 3 L