Isopropyl iodide → Methyl 6-bromo-3-formyl-1-isopropyl-1H-indazole-4-carboxylate

Participants

Reaction Steps

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%.

Provenance & Evidence