Asymmetric Catalytic Activity Of Biporphyrin Catalysts And Biological Activity Of Benzofuran Derivatives

Enantiomers performed small to large differences in optical and physiological characteristics,generally.The " Thalidomide " event was due to the pharmacological action of the right-handed body of the peptidyl piperidone is sedative and the left-handed body is teratogenic.Therefore,it is of great value and significance to study cheap and simple methods to obtain single,optically pure enantiomer.Chiral allyl alcohols are important intermediates for chemical synthesis and structural modification,they are widely used in the synthesis of medicine,pharmacy,natural products and fine chemical products.The synthesis of chiral allyl alcohol can be obtained by asymmetric allylation addition reaction of aldehyde with trichlorohydrosilane.Based on the chiral ester of 1,1'-carboline N,N'-dioxane could catalyze the allylic addition of trichlorosilane to aldehyde,in order to exploring the structure-activity relationship between the asymmetric allylation of the catalysts and the aldehydes deeply,we continued to modify the ester groups at the C-3 and C-3' positions of 1,1'-carboline N,N'-dioxane.After the ester groups were reduced to be hydroxyl groups,etherifications were carried out,followed by nitrogen oxidation to afford a series of chiral ligands with linear,branched,or cyclic aromatic ether group substituents.The ligands were subjected to chiral resolution by high performance liquid chromatography.Single enantiomer was successfully prepared.The ligands absolute configuration were confirmed by comparing the optical rotation value with the reported data.These catalysts were applied for asymmetric allylic addition of aldehydes.The experimental results show that these catalysts had high enantioselectivity in the allylations.In the optimization study,suitable reaction condition was using dichloromethane(DCM)at-80 °C for small substrate aldehydes with 1 mol% of chiral ligands,91%ee of product was achieved using(S)-12 k.The highest 96%ee was recorded when large substrates were used.Benzofuran and its derivatives have good antibacterial,cytotoxic and insecticidal activities.Oxadiazole and other pharmacophores show a wide range of biological activities such as antibacterial,weeding,etc.According to the principle of bioactive fragment splicing,The benzofuran nucleus is linked to the oxadiazole to give(E)-N'-benzyl-2-((2,2-dimethyl-2,3-dihydrobenzofuran-7-yl)oxy)Acetylhydrazine derivatives and 2-((2,2-dimethyl-2,3-dihydrobenzofuran-7-yl)oxy)methyl)-5-phenyl-1,3,4-Two series of compounds of oxadiazole derivatives were tested for their antibacterial activity,cytotoxic activity and herbicidal activity,respectively,and the results showed that the oxadiazole series compounds had good herbicidal activity.In summary,a series of novel chiral Lewis base catalysts derived from L-tryptophan have been successfully introduced to catalyze the asymmetric allylation of aldehydes with high yield(96%)and high enantioselectivity(96%ee).In addition,the oxadiazole fragment was ligated with benzofuran and its biological activity was found to be good for herbicidal activity.