反应详情

To a solution of 1H-indazole-6-carboxylic acid (3.00 g, 18.5 mmol) in N,N-dimethylformamide (46 mL) was added sodium carbonate (2.06 g, 19.4 mmol), followed by iodomethane (2.75 g, 1.21 mL, 19.4 mmol) dropwise. The mixture was stirred at room temperature overnight. The mixture was poured into half saturated sodium bicarbonate and extracted with ethyl acetate three times. The combined organic layers were washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to afford a brown oil. This residue was purified by flash column chromatography (12-100% ethyl acetate/heptanes) to afford methyl 1H-indazole-6-carboxylate as a yellow solid (2.95 g, 90%). 1H NMR (400 MHz, CDCl3, δ): 10.40 (br. s., 1H), 8.26 (s, 1H), 8.13 (s, 1H), 7.84 (d, J=8.4 Hz, 1H), 7.79 (d, J=8.4 Hz, 1H), 3.96 (s, 3H).

1. extractionextracted with ethyl acetate three times
2. washThe combined organic layers were washed with brine
3. dry with materialdried over sodium sulfate
4. filtrationfiltered
5. concentrationconcentrated in vacuo
6. customto afford a brown oil
7. customThis residue was purified by flash column chromatography (12-100% ethyl acetate/heptanes)