Potassium Nitrate → HCID 18996956, compound

Participants

Reaction Steps

Concentrated sulphuric acid (20 ml) was cooled to 5° C., and 9,10-dihydro-4,5-dimethoxy-9,10-dioxoanthracene-2-carboxylic acid (1 g) was added portionwise during fifteen minutes, resulting in a deep crimson coloration. Maintaining the cool temperature, potassium nitrate (0.36 g) was added portionwise during 10 minutes. Stirring continued at 5° C. for a further 15 minutes before the mixture was allowed to warm to room temperature. Upon reaching room temperature, the mixture was heated to 40° C. for 1 hour. The material was then poured onto ice/water (100 ml), generating a yellow precipitate. This solid was collected by filtration and washed with water (1×100 ml). Drying in vacuo over silica gel yielded 9,10-dihydro-4,5-dimethoxy-9,10-dioxo-8-nitro-anthracene-2-carboxylic acid as a signal yellow powder, decomposition point 230° C.

Provenance & Evidence