Yield:-

Reaction Conditions:

with acetic acid;sodium nitrite in water at 20;Cooling with ice;

Steps:

37.1
First Step [Show Image] To a glacial acetic acid solution (120 mL) of 2,3-dimethyl-5-nitroaniline [which can be synthesized, for example, by the method described in WO2005117819] (1.0 g, 6.02 mmol), an aqueous solution (3 mL) of sodium nitrite (0.42 g, 6.14 mmol) was added under ice cooling. The mixed solution was stirred under ice cooling for one hour, and then stirred at room temperature for 2 days. Acetic acid was distilled off under reduced pressure and water was added to the resulting residue, followed by stirring under ice cooling for 30 minutes. The precipitate was collected by filtration to obtain 1.14 g of 6-nitro-4-methylindazole. ¹H-NMR (500 MHz, DMSO-d₆) d: 2.67 (s, 3H), 7.75 (s, 1H), 8.27 (s, 1H), 8.37 (s, 1H).

References:

Carna Biosciences Inc.;Crystalgenomics, Inc. EP2226315, 2010, A1 Location in patent:Page/Page column 42