4,6-DIMETHYL-1H-INDOLE-2,3-DIONE synthesis

Yield:49820-06-6 44%

Reaction Conditions:

with sulfuric acid at 80; for 0.5 h;

Steps:

89

N-(3,5-Dimethyl-phenyl)-2-hydroxyimino-acetamide (13.7 g, 71.3 mmol) was added to concentrated sulfuric acid (70 mL) in a 250 mL flask. The reaction mixture was then heated at 80° C. for 30 minutes, then cooled to room temperature, and poured into ice-water (200 mL). The precipitated solid was filtered and washed with water (100 mL) and dried under vacuum to give 4,6-dimethyl-1H-indole-2,3-dione as an orange solid. Yield: 5.53 g (44%)

References:

US2013/281399,2013,A1 Location in patent:Paragraph 0696