Inorganic Catalysis For Ginsenoside Three Alcohol&Separation And Purification Of The Product

This paper mainly studies transforming ginsenoside-Re into ginsenoside-Rg2 and ginsenoside-R1]using Fe3+ as catalyst(the Rg2 group mainly consists of 20(S)IRg2,20(R)-Rg2,Rg4,Rg6,the Rh1 group mainly consists of 20(S)-Rhi,20(R)-Rh1,Rh4),and exploring the optimal conditions of their generation,including Fe3+ concentration,substrate concentration,temperature and reaction time.The experiment preliminarily determines that the optimal conditions for generating Rg2 via catalyzing ginsenoside-Re are:substrate concentration 25%,Fe3+ concentration 100 mmol/L,reacting under 80? for 1 hour with the 56.4%of production rate.The optimal conditions for Rh1 being the main product of the reaction is:substrate concentration 25%,Fe3+ concentration 100mmol/L,reacting under 90?for 2.5 hours with the 60.1%of production rate,and analyzing the main contents of Rg2 and Rh1 using HPLC,the of production rate is 56.42%and 60.13%.By TLC analyzes,Re firstly transfers into Rg2 group via hydrolysis by Fe3+(Rg2 includes 20(S)-Rg2?20(R)-Rg2?Rg4 and Rg6),and will transfer into Rhi group through further hydrolysis by Fe3+(Rg2 includes 20(S)-Rh1?20(R)-Rh1?Rk3 and Rh4).In the product under the optimum conditions for the Rg2 group,the use of inorganic Fe3+catalyzed hydrolysis of ginsenoside PPT,conversion to generate secondary ginsenosides rare sugar base,using AB-8 macroporous resin hydrolysis product of ginsenosides adsorption,catalysis product off the sugar and iron ions.The results showed that 5 column volumes of deionized water to complete elution of Fe3+ ions and sugar,and 7 column volumes of 84%ethanol to complete elution of ginsenoside.Using the AB-8 macroporous resin can be Fe3+and Ginsenoside completely separated,10 g PPT substrate obtained by hydrolysis of Fe3+7.78 g of crude product yield was 77.8%.7.78 g of the crude product by silica gel column chromatography,to obtain a more pure isolated 20(S,R)-Rg2 1.38 g;relatively pure mixture Rg4 and Rg6 1.21 g;relatively pure 20(S,R)-Rhi 1.33 g;relatively pure Rk3 and Rh4 mixture 1.12 g.By HPLC analyzes,the purity of 20(S,R)-Rg2 is 59.73%?40.27%and 20(S,R)-Rhi is 61.51%and 38.49%.