Lithium Hydroxide → HCID 22933674, compound

Participants

Reaction Steps

A 2N-aqueous lithium hydroxide solution (28.6 ml, 57.2 mmol) was added to a solution of a mixture of (4,7-dimethyl-1H-indazol-5-yl)acetate and (6,7-dimethyl-1H-indazol-5-yl)acetate (approximately 1:1, 5.30 g, 26.0 mmol) in methanol (30 ml) under ice-cooling, and the resulting mixture was stirred at room temperature for 1.5 hours. A saturated aqueous ammonium chloride solution was poured into the reaction solution, followed by extraction with ethyl acetate, whereby a mixture of 4,7-dimethyl-1H-indazol-5-ol and 6,7-dimethyl-1H-indazol-5-ol (4.31 g, 100%) was obtained. To this mixture were added tetrahydrofuran (200 ml) and N-chlorosuccinimide (1.74 g, 13.0 mmol), and the resulting mixture was stirred at 50° C. for 3 hours. The reaction solution was poured into water to terminate the reaction, and was extracted with ethyl acetate. The extract solution was washed with a saturated aqueous sodium chloride solution, dried over sodium sulfate, and then distilled under reduced pressure to remove the solvent, whereby a crude product was obtained. The crude product was washed three times with methanol to obtain 4-chloro-6,7-dimethyl-1H-indazol-5-ol (440 mg). On the other hand, the solvent of the filtrate was distilled off under reduced pressure and then the residue was purified by a silica gel column chromatography (hexane/ethyl acetate=2:1) to obtain 4-chloro-6,7-dimethyl-1H-indazol-5-ol (980 mg, 1.42 g in total, 56%).

Provenance & Evidence