1H-Indazole-6-carboxylic acid, 3-forMyl- synthesis

Yield:319474-35-6 2.35 g (100%)

Reaction Conditions:

with sodium nitrite in water;

Steps:

53.a 3-(1H-Benzoimidazol-2-yl)-N-(4-hydroxyphenyl)-1H-indazole-6 carboxamide

The starting material was prepared as follows: To 1H-indole-6-carboxylic acid (2.0 g, 12.42mmol) in water (10 0 mL) was added NaNO₂ (8.56 g, 124.2 mmol). To this suspension was then slowly added dropwise via addition funnel 6N HCL (16mL). The resulting slurry was allowed to stir at room temperature overnight. The solid precipitate was filtered and washed with water (50 mL) to provide 2.35 g (100%) of 3-formyl-1H-indazole-6-carboxylic acid. ¹H NMR (DMSO-d₆) δ 14.46 (1H, s), 10.21 (1H, s), 8.26 (1H, s), 8.20 (1H, d, J=8.5 Hz), 7.90 (1H, d, J=8.3 Hz). MS (APCI positive) 205 (methyl ester).

References:

US6531491,2003,B1