Methanol → methyl 1H-indazole-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

To indazole-3-carboxylic acid (40 g, 247 mmol) suspended in methanol (700 mL) was added concentrated H2SO4 (10 mL) slowly while stirring the mixture. The mixture was stirred and refluxed at 80° C. for 24 h. The mixture was cooled, filtered, and concentrated under reduced pressure to afford a pale yellow solid. The solid was suspended in water (700 mL), crushed to fine powder, collected by filtration, and rinsed with water (˜400 mL). The product was suspended in toluene, and evaporated to dryness under reduced pressure, affording indazole-3-carboxylic acid methyl ester as a pale yellow solid (45 g, >95% pure). (m/z): [M+H]+ calcd for C9H8N2O2 177.07; found, 177.0. 1H-NMR (CD3OD, 300 MHz): δ (ppm) 8.0 (1H, d), 7.5 (1H, d), 7.4 (1H, t), 7.2 (1H, t), 3.9 (3H, s).

Provenance & Evidence