Preparation of 4,5-dihydroxy-9,10-anthraquinone-2-carboxylic acid (rhein) (I) and its derivatives comprises treating a diphenyl ketone (IV) with a concentrated strong acid to obtain quinone derivative (V), either treating (V) with a strong base in aqueous medium to obtain (Ia) or treating (V) by tetrabutyl ammonium methylate to obtain monomethyl ether of rhein (Ib), where (Ia) and (Ib) are representatives of (I). Preparation of 4,5-dihydroxy-9,10-anthraquinone-2-carboxylic acid (rhein) and its derivatives, of formula (I) comprises treating a diphenyl ketone of formula (IV) with a concentrated strong acid to obtain quinone derivative of formula (V), either treating (V) with a strong base in aqueous medium to obtain (Ia) or treating (V) by tetrabutyl ammonium methylate to obtain monomethyl ether of rhein (Ib), where (Ia) and (Ib) are representatives of (I). X, Y 1-OH, -OCH 3 or -O-C(O)-CH 3； Z : halo comprising F, Cl, Br or I, preferably Cl in (V). In (Ia):X = Y 1 = -OH. In (Ib): X : -OCH 3； and Y 1OH. In (IV): Y 1-OR； and R : 1-4C alkyl. In (V): Y 1OH. Independent claims are included for: (1) quinone derivative (V)； (2) preparation of (IV) comprising Friedel-Crafts reaction between a benzoyl halide substituted in ortho position by a halogen (fluorine, chlorine, bromine or iodine) and dimethyl-3,5-phenyl in the presence of one molar equivalent of a Lewis acid catalyst, preferably anhydrous aluminum chloride, to obtain (2-halo-phenyl)-(2-hydroxy-4,6-dimethyl-phenyl)-methanone of formula (VI), protection of the phenol group of (VI) by action of a lower alkyl halide/sulfate in the presence of a basic agent to obtain (2-halo-phenyl)-(2-alkoxy-4,6-dimethyl-phenyl)-methanone of formula (VII) and oxidation of the methyl groups of (VII) by a transition metal oxide type oxidizing agent, in the presence of metallic catalysts, to obtain the diacid compounds (IV)； and (3) diphenyl ketone (IV). [Image] [Image] ACTIVITY : Antiinflammatory. MECHANISM OF ACTION : Interleukine-1 inhib
