METHOD FOR PREPARATION OF ALOE-EMODIN FROM ALOIN AND METHOD FOR PREPARATION OF REIN OR DIACEREIN FROM ALOIN Russian patent published in 2009 - IPC C07C50/34 C07C46/00 C07C66/02 C07C51/27 C07C69/16 C07C67/08 

FIELD: chemistry.

SUBSTANCE: present invention refers to the method for preparation of aloe-emodin, and rein or diacerein used for treatment of the diseases concerned with anomalous dystrophy of connective tissues. The method for preparation of aloe-emodin includes oxidation of aloin dissolved in the polyatomic alcohol with oxygen-containing gas in the presence of acid. The method for preparation of rein or diacerein includes the following stages: a) oxidation of aloin dissolved in the polyatomic alcohol with oxygen-containing gas in the presence of acid to aloe-emodin; b) oxidation of aloe-emodin with chrome-free oxidising media to rein; c) purification of the rein obtained on the stage b) and d) optional acetylation of the rein obtained on the stage c) with acetylation agent to diacerein. The claimed method allows obtaining of aloe-emodin with good yield and purity level without using of toxic or harmful substances and complicated purification methods.

EFFECT: claimed method allows also diacerein obtaining without using of hexavalent; chrome as oxidiser and without complicated purification methods.

17 cl, 1 tbl, 5 ex