Studies On The Syntheses Of Aurones And Daphni-phyllum Glaucescens Alkaloids Daphniyunnines

Studies on the total synthesis of complex natural products with biological activity and the organic synthesis methodology are the the focus of organic chemistry. Based on the improved Algar-Flynn-Oyamada reaction, a one-pot green synthesis of Aurones and Flavonols has been developed and all the conditions were optimized. Taking the bioactive molecules Daphniphyllum alkaloids Daphniyunnine as the target molecular, the exploration of building the main skeleton of Daphniyunnine was studied. The structure of the two adjacent chiral quaternary carbon and 5-6 ring system were successfully constructed using the tandem Michael Addition reaction. This paper includes the following two chapters:Chapter I. A one-pot syntheses of Aurones and Flavonols based on the improved AFO reaction.As the two kinds of important flavonoids, Aurones and Flavonols were always the focus of natural products. This chapter described the classification structure, biological activity, medicinal value of the flavonoids. Based on the improved Algar-Flynn-Oyamada reaction, a one-pot synthesis of aurones has been developed from substituted acetophenone and benzaldehyde and the optimization of conditions and the scope of applicability of the substrate were showed. In the same time, syntheses of 17 Aurones and Flavonols were achieved. Using this method, some of aurones could be prepared in three steps from commercial starting materials. The features of one-pot strategy were proved by synthesis of aureusidin in 41% overall yield. In addition, the first total synthesis of Diplotrin B and total synthesis of Aureusidin were achieved. Comparing to the two-step operation from the same substrates, the one-pot strategy was more effective including that the yield was higher and the operation was simpler. The two type of compounds similar to each other were confirmed by X-Ray single crystal diffraction structure of Aurone 1-47 and flavonol 1-76.Chapterâ…¡. Studies on the Daphniphyllum Glaucescens Alkaloids Daphniyunnines.Daphniphyllum alkaloids are a serious of complex natural products bearing a polycyclic rigid structure and anti-tumor cytotoxic biological activity. So far as, about 60 of these compounds has been identifide. This chapter describes the discovery, the separations, the molecular structural characteristics, biomimetic synthesis, semi-synthetic studies of the Daphniphyllum alkaloids systematically.In 2006, Daphniyunnines A-E were separated by Yue Jianming, etc. from the large leaves of Daphniphyllum plants leaves and stems. In view of the extremely complex coupled quaternary carbon and crowded rigid structure, there is no report about the total synthesis of Daphniyunnine. The first total synthesis of Daphniphyllum alkaloids is still a challenge for synthetic organic chemists.This chapter described the exploration on building the 5-6-7 ring system skeleton using the intermolecular Diels-Alder reaction or Double-Michael addition reaction as the key reaction. Providing a valuable synthesis of experience, intramolecular Double-Michael addition reaction was used as the key reaction to build a highly saturated two adjacent bridgehead quaternary carbon of the 5-6 ring system.