反应详情

To a stirred solution of methyl 6-bromo-3-formyl-1H-indazole-4-carboxylate 1 (11.5 g, 40.63 mmol) in DMF (230 mL)) was added K2CO3 (14.08 g, 102.02 mmol) at RT under argon, and stirred for 10 min. Then 2-iodopropane (7.24 g, 42.58 mmol) was added at RT and the mixture stirred at 40° C. for 2 h. The reaction mixture was diluted with cold water and extracted with ethyl acetate (4×300 mL). The combined organic layers were washed with water, brine, dried over anhydrous Na2SO4, filtered, and concentrated. The crude residue (12.4 g) was purified by silica gel chromatography (eluent: 0-10% ethyl acetate: pet ether) to afford the title compound as an off white solid (5.55 g, 42%). 1H NMR (CDCl3, 400 MHz): δ 1.659 (d, J=6.4 Hz, 6H), 4.017 (s, 3H), 4.862-4.960 (m, 1H), 7.807 (s, 1H), 7.854 (s, 1H), 10.375 (s, 1H). HPLC: 98.66%.

1. stirringthe mixture stirred at 40° C. for 2 h
2. extractionextracted with ethyl acetate (4×300 mL)
3. washThe combined organic layers were washed with water, brine
4. dry with materialdried over anhydrous Na2SO4
5. filtrationfiltered
6. concentrationconcentrated
7. customThe crude residue (12.4 g) was purified by silica gel chromatography (eluent: 0-10% ethyl acetate: pet ether)