Synthesis Research For Rhein

Rhein is an anthraquinone ramification monomer existing in rhubarb, what has awidespread pharmacological actions. As reported rhein is useful as a medicament possessinganticancer, antimicrobial, blood suger lowering, antiphlogistic, alexipharmic, antimutation,antioxidant, luring and killing virus B3and bidirectional contral immunity functon. And isalos considered a medicament possessing multiple targets effect. Simultaneously it is theoriginal material of diacerein used for treating arthropathy. At present rhein has beencommonly studied and clinical application by the scientific community.In the present study a new and secure process for preparing the production of rhein fromaloe-emodin viaing two steps is proposed. It provides the methods that are not only be moreefficient by reducing reaction steps, besides it functions with chromium-free oxidizingmedium. First we oxidate aloe-emodin to aldehyde Aloe-emdion by trichloroisocyanuricacid(TCCA) as the oxidant and the4-Hydroxy-2,2,6,6-tetramethyl-piperidinyloxy (TMHPO)as the catalyst. Second we get the rhein by further oxidatin using hydrogen peroxide, and thegross receiving rate can reach69.36%. This dissertation made a research on the follwingfactors such as reaction temperature, time, catalyst and dosage of all kinds of materials.Finally, the single factor to consummate the technological process and technological conditionwas introduced, and the optimal process parameters were got.The structures of the synthesis products were characterized by H Nuclear MagneticResonance(H-NMR), high performance liquid chromatography(HPLC), microscope, andmelting point meter. Results showed that: the structures and performances of the productsconformed to the anticipation; the yiel of each reaction was more than80%. These canconclude that the way using Aloe-emdio as original material for synthesize rhein is practicaland effective.