Hydrochloric Acid → 6-amino-5-methyl-2H-indazole-7-carboxylic acid

Participants

Reaction Steps

To a solution of 5-methyl-1,6-dihydro-pyrrolo[2,3-g]indazole-7,8-dione (23 g, 114.3 mmol) in 4N aqueous sodium hydroxide solution (160 ml) at ambient temperature, was added dropwise 30% aqueous hydrogen peroxide solution (27 ml) maintaining the temperature <30° C. with external cooling. The resulting reaction mixture was stirred at ambient temperature for 2 hours. According to TLC, the reaction was complete after 2 hours. The pH was adjusted to pH 3.5 by addition of concentrated hydrochloric acid. The resulting brown suspension was filtered and the filtercake washed with cold water and dried in vacuo at 50° C. to afford the desired product as brown solid. LC/MS: 192 (M+H)+.

Provenance & Evidence