Indazole-3-carboxylic acid → methyl 1H-indazole-3-carboxylate

Participants

Reaction Steps

To a solution of 1H-indazole-3-carboxylic acid (5.0 g, 30.8 mmol) in methanol (50 mL), thionyl chloride (15 mL) was added dropwise at 0° C. After the addition, the mixture was heated to reflux and maintained at the temperature for 1.5 hours. Then the reaction mixture was concentrated to give a residue. To the residue was added saturated sodium bicarbonate (50 mL), and then extracted with ethyl acetate (50 mL×3). The organic phase was combined and dried over anhydrous sodium sulfate. The mixture was filtered and the filtrate was concentrated under reduced pressure to give methyl 1H-indazole-3-carboxylate as a white solid (5.1 g, 94%). 1H NMR (300 MHz, d6-DMSO): δ 13.91 (s, 1H), 8.06 (d, J=8.2 Hz, 1H), 7.65 (d, J=8.4 Hz, 1H), 7.44 (ddd, J=8.3 Hz, J=6.9 Hz, J=1.1 Hz, 1H), 7.30 (ddd, J=7.9 Hz, J=6.9 Hz, J=0.9 Hz, 1H), 3.92 (s, 3H).

Provenance & Evidence