5-bromo-7-ethyl-1H-indazole → 7-ethyl-1H-indazole

Participants

Reaction Steps

To a solution of 5-bromo-7-ethyl-1H-indazole (900 mg, 4.00 mmol) in ethanol (16.0 mL) flushed with nitrogen was added palladium on carbon (128 mg, 1.2 mmol) and the mixture stirred under H2 at 1 atm. After 70 h the reaction was filtered over a pad of celite. The filtrate was collected and concentrated. The residue was dissolved in ethanol and 80 mg of palladium on carbon was added and stirred under H2 at 1 atm. After 3 h another 80 mg of palladium on carbon was added and stirred under H2 at 1 atm. After 16 h the reaction was filtered through a pad of celite. The filtrate was collected and concentrated. The yellow solid obtained was triturated with ether, filtered and dried under vacuum to give 7-ethyl-1H-indazole (771 mg, 5.27 mmol, 119%) as an off white solid. This was used directly without further purification. MS (M+H)+=146.8; 1H NMR (CDCl3) δ: 8.54 (s, 1H), 7.78 (d, J=8.2 Hz, 1H), 7.59 (d, J=7.1 Hz, 1H), 7.43 (t, J=7.1 Hz, 1H), 3.25 (q, J=7.4 Hz, 2H), 1.48 (t, J=7.5 Hz, 3H).

Provenance & Evidence