Flavanone Green Synthetic Methods Based On Pyridine - Water System

Flavanone derivatives are one of a variety of active ingredients of medicinal plants. Because of its anti-bacterial, anti-inflammatory, anti-tumor and other physiological activity, it has attracted many chemists to do research on them.In this paper, the flavanones have been synthesized from 2'-hydroxychalcone and substituent of 2'-hydroxychalcones that was synthesized in the prence of mixed solvent pyridine-water by heating or lighting.In the heated reaction, the effects of pyridine-water volume ratio, heating temperature, reaction time to yield of flavanone was investigated through single-factor experiments and orthogonal test The optimized conditions were pyridine - water volume ratio of 4:6, the heating temperature is 90℃, reaction time is 60min. The yield of flavanones were analyzed comparatively with other alkaline solvent under the same conditions. In addition, a series of 2'-hydroxychalcone derivatives was synthesized as raw materials, investigated the effect of pyridine - water system on the B ring substituted flavanones with different yield, and suggesting that the cyclization mechanism of the 2'-hydroxy chalcone and its derivatives in the pyridine - water system by heating.In the light reaction, the effects of pyridine-water volume ratio, light intensity, reaction time to yield of flavanone was investigated through single-factor experiment.The results show that the optimal reaction conditions: pyridine - water volume ratio of 4:6,the quantum yields of flavanone are of independent of light intensity, reaction time of 7.5h. And the effect of other cyclization reagents to the yield of flavanone was studied in optimized conditions and found production rate is highest in pyridine-water system. The yield of flavanones were analyzed comparatively with other alkaline solvent under the same conditions. Similarly, a series of 2'-hydroxychalcone derivatives was synthesized as raw materials, investigated the effect of pyridine - water system on the B ring substituted flavanones with different yield under the best ligting conditions..In this paper, the heating and lighting cyclization reaction in pyridine - water system of with high yield of flavanone, no side product, simple operation, short reaction time, solvents to be recycled easily and other advantages, is expected as a new synthetic flavanone green approach to research and development.