The Synthesis Of Flavonoids And Intermediates

Flavanone belongs to flavonoid, is a class of polyphenols organic compounds widely distributed in nature, mainly occurs in fruits, vegetables, pasture and medicinal plants, it is the active ingredient in many Chinese herbal, and the secoralany metabolite produced from the long-term natural selection as well. Due to broad spectrum pharmacological activity, low toxi and side effects, flavanone has been the hot topic on the research, development and utilization of natural medicine at home and abroad. However, the low content of flavanone in the natural products and difficulties of extraction process, it will be of great significance recently for the study of new drug to seek lead compounds of flavanone and remould or modify their structures. This paper studies the synthesis of flavanone and its intermediates, attempting to optimize the routes and makes the reference for more research to benefit mankind.As the important intermediate in the synthesis of isoflavone compounds, benaoin has been a prority for all in the chemical research over the years. But there are no satisficatory discoveries on the creative synthesis to magnify for industrial production. Because benaoin itself has certain pharmacological bioactivies, we attempt to explore a new synthesis method to solve those problems. We hope this work can not only give a summary of the past research, but also make contributions to this field in the future.Based on the earlier work in our laboratory, we have successfully synthesized expected flavanones by the method called one-pot, and applied to the synthesis of analogues as well, which greatly reduced the toxicity and cost of reactions. Meanwhile, we obtain a green chemical synthesis route of flavanone. In this paper, we also study the synthesis of 2,4,6,4’-tetrahydroxydeoxybenzion, and adapt a novel way with great satisfactory results in the aftertreatment.This paper is composed of two sections as follows:Part one:The synthesis of flavanonesIn this part, based on plenty of early experiments, we tried the traditional synthetic routs and made innovation on the process, finally obtain a synthetic method suited for most of flavanone. During the specific work, we synthesized the 2-hydroxy-4,6-dimethoxyacetophenone via a variety of methods, and then obtained the 5,7,4’-trimethoxyflavanone with p-anisaldehyde by one-pot. In the end, Naringenin was synthesized by demethylation. We applied the same way to the synthesis of analogues with good purity and productivity.Part two:The synthesis of 2,4,6,4’-tetrahydroxydeoxybenzionWe designed a novel route to finish this part. Through p-anisaldehyde to obtain methoxymandelic acid by Cabbeen Reaction, and then gave p-methoxyphenoxyacetic acid by the Reduction reaction with SnCl2·2H2O. With 1,3,5-trimethoxybenzene by the Friedel-Crafts reaction, obtained 2,4,6,4’-tetramethoxydeoxybenzoin. Finally, we obtained the target product of 2,4,6,4’-tetrahydroxydeoxybenzion by demethylation.