Acetic Acid → 4-Nitroindazole

Participants

Reaction Conditions

Reaction Steps

Alternatively, a 4-necked 5-L jacketed round bottom flask fitted with a mechanical stirrer and a thermocouple was charged with 2-methyl-3-nitroaniline (100 g, 658 mmol) and acetic acid (2000 mL). The solution was cooled to 14° C. and treated with a chilled (˜1° C.; ice-water bath) solution of NaNO2 (100 g, 1450 mmol) in water (250 mL) added in one portion. The internal temperature rose from 14° C. to 28° C. over 5 min and remained at this temperature for 5 min. before gradually cooling to 15° C. The mixture was stirred for 24 h after and was then concentrated under reduced pressure to an approximate volume of 500 mL. The residue was resuspended in water (1800 mL) at ambient temperature for 21 h. The resulting orange solid was filtered, washed with water (3×250 mL), and dried in a vacuum oven at 70° C. to afford 97.0 g of the title compound as a bright orange solid which was used without further purification.

Provenance & Evidence