反应详情

5-Bromo-pyridine-2-carboxylic acid (34, 0.417 g, 2.06 mmol) was dissolved in 19 mL of tetrahydrofuran. N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (0.633 g, 3.30 mmol), N,N-diisopropylethylamine (1.81 mL, 10.4 mmol), and 1-hydroxybenzotriazole (0.363 g, 2.68 mmol) were added, followed by 2.00 M ethylamine in tetrahydrofuran (35, 1.20 mL, 2.40 mmol). The reaction mixture was stirred overnight at room temperature, after which 1.5 mL of dimethylformamide was added and stirred for another 4 hours. The resulting mixture was poured into water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under vacuum. The crude material was purified by silica gel flash chromatography. The appropriate fractions were combined and the solvents removed under vacuum to provide the desired compound (36, 163 mg). MS (ESI) [M+H+]+=229.29, 231.3.

1. stirringstirred for another 4 hours
2. extractionextracted with ethyl acetate
3. washThe combined organic layers were washed with brine
4. dry with materialdried over anhydrous sodium sulfate
5. filtrationfiltered
6. concentrationThe filtrate was concentrated under vacuum
7. customThe crude material was purified by silica gel flash chromatography
8. customthe solvents removed under vacuum