Sulfuric Acid → Anthraquinone-2-aldehyde diacetate

Participants

Reaction Conditions

Reaction Steps

To a solution of 2-methylanthraquinone (16.0 g, 72.0 mmol) in a mixture of acetic acid (400 ml) and acetic anhydride (400 ml) was added concentrated sulfuric acid (16 ml) at 5° C. Chromium trioxide (18.0 g, 0.18 mmol) was added over a period of 1 hour at 5° C. The reaction mixture was then stirred at 5° C. for 4 hours, poured into ice water, and extracted with chloroform. The organic extract was dried over MgSO4 and concentrated under vacuum to give anthraquinone-2-aldehyde diacetate (16.0 g, 65%.) To a solution of the anthraquinone-2-aldehyde diacetate (16.0 g, 47.3 mmol) in acetic acid (400 ml) was added dropwise 35% aqueous hydrochloric acid (170 ml) at room temperature. The reaction mixture had been stirred while refluxing for 15 min, cooled to room temperature, filtered off with suction, and washed with water. After drying, anthraquinone-2-aldehyde (10.0 g, 89%) was obtained.

Provenance & Evidence