Sulfuric Acid → 4,6-Dichloroisatin

Participants

Reaction Conditions

Reaction Steps

The N-(3,5-dichlorophenyl)-2-hydroxyiminoacetamide just prepared (12.1 g, 0.052 mol) was added to 96 per cent strength sulfuric acid (56 ml) at 50-75° C. in the course of 15 min. The reaction mixture was then heated at 90° C. for 15 min, while stirring. After cooling, the mixture was poured slowly on to ice (500 g). The solid formed was filtered off with suction after 30 min. The desired isatin was isolated in a yield of 81% (9.12 g) as an orange-coloured solid. It was not possible to determine a melting point.

Provenance & Evidence