The Studies On The Synthesis Of Benzofuran Neolignan Derivatives With Biological Activities

Benzofuran neolignans are widespread in nature, including 2-phenyl benzofuran neolignjans and its dihydro, tetrahydro, hexhydro derivatives and exhibit a broad range of biological activities and are potent ingredients of many medicine plants. In order to meet the needs for selecting the substances with biological activities and developing new drugs, this thesis aims at the studies on the syntheses of benzofuran neolignan derivatives and dihydrobenzofuran neolignan derivatives.First, the definition, structure classification, physical and chemical characters and biological activities of lignan compounds were introduced in the thesis. Meanwhile, their application in pharmacology and taxonomy was also mentioned. Second, in each chapter the biological activities and the previous synthetic reports of benzofuran neolignans and dihydrobenzofuran neolignans were also introduced respectively.Aiming at constructing dihydrobenzofuran skeleton, synthetic routes were devised. On the basis of these devices, four compounds (1)⁴ have been synthesized, which belong to dihydrobenzofuran neolignans and benzofuran neolignans derivatives. The synthetic routes as following:1. Starting from 3-methoxy-4-hydroxybenzaldehyde and malonic acid, new compound (1) was synthesized via Knoevenagel reaction, esterification reaction, Ag₂O-catalyzed biomimetic oxidative coupling reaction and methylized reaction in four steps.2. Starting from compound (1). (2), (3) and (4) were synthesized via DDQ dehydrogen reaction, lithium aluminium hydride reductive reaction and MnO₂/SiO₂ (m:m=1:1) oxygenative reaction in three steps. This device route included seven stepsof synthesis, its advantages were simpleness of operation and high yield (overall 20%).Not only achieved transformation successfully from dihydrobenzofuran neolignans tobenzofuran neolignans, but also offered a new method to synthsis benzofuran con-struction. So this synthetic route has applied value.Thereinto Ag₂O-catalyzed bio-mimetic oxidative coupling reaction was a key step of this synthetic route.Aiming at constructing dihydrobenzofuran skeleton, synthetic routes were devised. On the basis of these devices, four compounds (6)⁹ have been synthesized, which belong to dihydrobenzofuran neolignans and benzofuran neolignans derivatives. Decorating the structure of a dihydrobenzofuran neolignan, 8,5'-neolignan compound (5) has been firstly synthesized, which supplies a new synthetic approach to 8,5'-neolignan...