| abstract |
The following description sets forth a process for producing rhein, diacerhein and other diacyl derivatives thereof, which comprises the following steps: treatment of a diphenylketone <CHEM> in which R1 is -OR', -NR'R'', -SR', where R' and R'' are H, an alkyl or aromatic group; R2 is H or a protective group. R3 is -OH or C1-C4 alkyl, with an acid or superacid to give a 1-aminoanthraquinone derivative, diazotisation, replacement of the -NH2 group by -OH, optional removal of the protective group, and acylation. |