1,4-Cyclohexadiene-1,4-dicarboxylic acid, 2,5-bis(phenylamino)-, 1,4-dimethyl ester → Quino(2,3-b)acridine-7,14-dione, 5,6,12,13-tetrahydro-

Participants

Reaction Conditions

Reaction Steps

To 120.0 g of polyphosphoric acid (118%) was added with stirring 20.0 g (52.9 mmol) of 2,5-bis(phenylamino)-1,4-cyclohexadiene-1,4-dicarboxylic acid dimethyl ester. The stirred mixture was irradiated in the microwave oven for 1.5 minutes. After the reaction mixture was cooled to 80° C., water was added with stirring. The resultant slurry was stirred for 5 minutes, after which the solid component was collected by filtration and washed with 3.0 liters of water. The presscake was dried overnight in an oven at 60° C. to give 15.9 g of 6,13-dihydroquinacridone (95.7% yield, 97.0% spectroscopic purity).

Provenance & Evidence