Process for preparing aloe-emodin
AssigneeLaboratoire Medidom S.A.
InventorsStefano Carlino, Guido Di Napoli
Life of this patent
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Abstract
A process for preparing aloe-emodin from aloin by oxidizing aloin by treatment with an oxygen-containing gas in the presence of an acid. The aloe-emodin may be used for the production of rhein and diacerein by oxidizing aloe-emodin by treatment with a chromium-free oxidizing medium to obtain rhein and purifying the rhein obtained. The rhein may be acetylated to obtain diacerein.
Claims18
A process for preparing aloe-emodin from aloin comprising oxidizing aloin by treatment with an oxygen-containing gas in a reaction stable medium in the presence of an acid.
A process for preparing rhein or diacerein from aloin which includes the steps of:
- a) oxidizing aloin by treatment with an oxygen-containing gas in the presence of an acid to obtain aloe-emodin;
- b) oxidizing aloe-emodin by treatment with a chromium-free oxidizing medium to obtain rhein;
- c) purifying rhein obtained in step b);
- d) optionally acetylating rhein obtained in step c) using an acetylating agent to obtain diacerein.
Dependencies are inferred from the claim text.