The Synthesis Of Biflavone And Mannich Bases Of Daidzein

Daidzein (7,4′-dihydroxyisoflavone) is one of the most important isoflavonoids. It hasbeen pharmacologically proved showing properties of anti-arrhythmic, resistance to hypoxiaand anoxemia, relieving spasticity, and estrogen. However, due to its poor water-andoil-solubility, the bio-use ratio of daidzein by oral absorbance is quite low, which limit itsclinical application. Thus, it has been the focus of some current researches to improve itsapplication field by improving its water-or oil-solubility.Biflavonoids are dimers formed from the coupling of two flavonoid or its derivatives,possessing a great biological activity, such as anti-oxidant, anti-microbial, anti-inflammatoryand anti-cancer competence. In this thesis, we studied the synthesis of novel biflavonoidsfrom the reaction of daidzein. The parameters of catalyst loading, reaction time, temperatureet al. were investigated. Single factor experiment and orthogonal experiment were used tooptimize the synthesis condition. The optimal condition was using9mol%catalyst, heatingthe reaction at90°C for20h. The products were obtained as white power with a yield of82.1%.Nitrogen-containing daidzein constitute a very important class of compounds andMannich reaction is one of the most important reactions for the synthesis ofnitrogen-containing compounds. In the thesis, the Mannich reaction of daidzein with a seriesof amines was studied. Using DMF as solvent,13kinds of daidzein derivatives were preparedand characterized by1H NMR,13C NMR, ESI MS. The results showed that10monosubstitutions derivatives were obtained through the reaction at C-8and3disubstitutedderivatives were obtained through the reactin at both C-8and C-3′. This indicate that C-8wasmore active than C-3′. Relating factors such as amine, reaction time, temperature, the molarratio of daidzein to dipropylamine, aldehydes at al. were investigated. The optimal conditionwas running the heating a mixture of aindzein and dipropylanime (1:1) at65°C for6h inDMF, and rhe yield could reach84.4%.Ultrasound has been extensively used in organic synthesis to accelerate reaction rate. Inthe thesis, we studied the influence of ultrasound on the Mannich reaction of daidzein with aseries of amines in H2O/t-BuOH (v:v:10:4). The influence of the power (100W,150W,200W) of the ultrasound, operational manner (continuous ultrasound,10min ultrasound/20min strring), ultrasound time and ultransound frequences were investigated. The result showed thatreaction time was shorten to1/3in presence of ultrasound to obtain the same vonversion aswith stirring. The influence of ultrasound power was also studied and150W was found to bethe most suitable one. The influence of ultrasound frequencies was also studied and45kHzwas found to be the most suitable one. It was evident that continul ultrasound caused greaterrate acceleration than interrvl ultrasound, and rhe yield could reach94.6%.