Sulfate Ion → 1-Hydroxy-5-[(1-methylethyl)amino]-9,10-anthracenedione

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Reaction Steps

This press cake is introduced with intensive stirring into 34.7 parts of 90% strength sulphuric acid, the solution is warmed to 120°-125° until no further 1-isopropylamino-5-methoxy-anthraquinone is chromatographically detectable in a worked-up sample (about 3 hours are required) and is diluted with 18 parts of water at 50°-80°, the mixture is stirred overnight in the cold, and the sulphate which has precipitated in large boat-shaped plates is filtered off, washed with 50% strength sulphuric acid, decomposed with water, and the product washed until neutral and dried. 12.9 parts (90% of theory) of 1-isopropylamino-5-hydroxy-anthraquinone are obtained.

Provenance & Evidence