Studies On Synthesis Of Anew 8-5’ Neolignan

Lignan compounds, kinds of natural products, are the oxidation polymer of phenylpropanoids and have unique pharmacological activity, widely distributed in nature. For their novel chemical structure, a plurality of chiral center and rich function groups, they became the focus of the chemists. Among them, the 8-5’neolignans, with wide range of physiological and pharmacological activity, are also widespread on earth. In this paper, we focus on the total synthesis of the 8-5’neolignan and the ring-opening reaction of the dihydrobenzofuran neolignan was explored. This paper includes the following three parts:Part one is the summery, we introduced the current study status and research progress of lianan compounds about its classification, biological activities and physicochemical properties. This section expound about the research on synthesis of the natural neolignans related in this thesis. Then we put forward the research topic combined with the current research situation.The second part introduced the first total synthesis of (E, E)-N, N-dityramin-4,4’-dihydroxy-3,5’-dimethoxy-B,3’-bicinnamamide. We used cheaper vanillin and DEM as raw materials, though Knoevenagel reaction to get the ferulic acid ethyl ester. In the presence of silver oxide, a biomimetic oxidative coupling of the ferulic acid ethyl ester is the crucial step in the synthesis sequence to generate the benzofuran skelenten, followed by the first reduction with LiAlH4 and AlCl3, though ring-opening reaction under alkaline conditions, Hydroxyl protection and hydrolysis to obtain intermediates diacid. The specific selectivity ligand of diacid was formed from tyramine which was obtained though the acylation reaction, phenol hedroxyl protection and selective removal of amino protecting group. Then the ligand reacted with diacid though the acylation reaction to obtain the latent target compound, after removing the protecting group, the target compound was obtained.The third part discussed some of the synthesized compounds and their reaction mechanism. These ring-opening reaction proved Dihydrobenzofuran ring under alkaline conditions are unstable and prone to open-loop, for 8-5’ synthesis of new compounds lignans provides new methods and approaches.