Sulfuric Acid → 5,6-difluoro-2,3-dihydro-1H-indole-2,3-dione

Participants

Reaction Conditions

Reaction Steps

A 24.5 g portion of N-(3,4-difluorophenyl)-2-(hydroxyimino)acetamide was added portionwise with stirring to 95 ml of concentrated sulfuric acid with the temperature kept between 60° and 70° C. The temperature of the reaction mixture was then raised to 80° C. for 20 minutes followed by cooling to room temperature. The mixture was then poured onto crushed ice and the resulting solid collected, giving 21.3 g of the desired compound as brick red crystals, mp 218°-220° C.

Provenance & Evidence