The reaction of anthracene with maleic and fumaric acid and their derivatives and with citraconic anhydride and mesaconic acid.

TLDR: The initial precipitate of long dense needles had become contaminated by a small superficial layer of fluffy crystalline balls, apparently containing the saturated dioltrione (XXIV) and after two further recrystallizations from alcohol melted at 23!-238’.

Abstract: lized from benzene by the addition of ether, giving 118 mg. of crude crystalline XXVI. This product was dissolved in 2.5 cc. of hot alcohol and the solution permitted to cool slowly to room temperature. It was then kept a t -5” for two days a t the end of which time the initial precipitate of long dense needles had become contaminated by a small superficial layer of fluffy crystalline balls, apparently containing the saturated dioltrione (XXIV) . The needles were easily separated mechanically and after two further recrystallizations from alcohol melted at 23!-238’. A total of 83 mg. was obtained;