Iodine → 3-Iodo-4,5,6,7-tetrahydro-1H-indazole

Participants

Reaction Conditions

Reaction Steps

To a mixture of 4,5,6,7-tetrahydro-1H-indazole-3-carboxylic acid (0.57 g, 3.43 mmol), and sodium bicarbonate (951 mg, 440 μL, 11.3 mmol) in dichloroethane (5 mL) and water (5 mL) were added in one portion sodium iodide (1.34 g, 8.92 mmol) and iodine (1.13 g, 4.46 mmol) and the mixture heated at to 100° C. (oil bath temperature) with vigorous stirring for 24 h. After cooling to 25° C. the mixture was diluted with dichloromethane, then washed with 10% Na2S2O3 and saturated NaHCO3. The organic phases were combined, dried (MgSO4) and concentrated to an off-white solid which was purified by chromatography (115 g column, 50 μm from Analogix, 0 to 5% over 15 min (MeOH containing 10% ammonium hydroxide)/dichloromethane to give 3-iodo-4,5,6,7-tetrahydro-1H-indazole (674 mg, 2.72 mmol, 79.2%) as a white solid. MS (M+H)+=249 (>90% purity); 1H NMR (CDCl3) δ: 2.75 (t, J=5.7 Hz, 2H), 2.35 (t, J=5.7 Hz, 2H), 1.61-1.90 (m, 4H).

Provenance & Evidence