Anthrarufin → 1,5-Dihydroxyanthrone

Participants

Reaction Conditions

Reaction Steps

To a suspension of 1,5-dihydroxyanthraquinone (10 g, 41.6 mmole) and stannous chloride (45 g, 237 mmole) in glacial acetic acid (150 ml), conc. hydrochloric acid (90 ml) was added at 16°-20° C. The mixture was stirred for 4 hours under reflux. After standing at room temperature overnight, the reaction mixture was cooled to 5° C. The precipitate was filtered, washed with H2O and dried to afford 8.0 g of 1,5-dihydroxyanthrone as dark brown needles having a m.p. of 231°-233° C.

Provenance & Evidence