The Synthesis And Biological Activity Of Lactone And Their Analogues

Environment friendly and green pesticides are paid more attention with the development of modern agriculture. Traditional pesticides have played an important role in the past years, but as high toxical compounds that hard to be degraded, they have also produced environment and social problems. Meantime, lead compounds based on natural product can be developed to be green,degradable pesticides, which means the research of this field will be very important.In this paper, the application of3-bromomethyl-5-H-furan-2-one in the synthesis of a-methylene-y-butyrolactone was explored as Zinc or Indium-mediated, and (+)-8-Epigrosheimin was total synthesized; then we made the structure modification of4-hydroxycoumarin to develop new green pesticide. There were65compounds synthesized and they were all characterized by1H NMR,13C NMR, HRMS. The preliminary bioassay of coumarin compounds shows that they proceed certain herbicidal bioactivity and can be researched as lead compounds, the work in the future can be continued. The work are as follows:We investigated the reactions of3-bromomethyl-5-H-furan-2-one with aldehyde in the presence of metal Zinc and Indium, as that’s an efficient route to synthesize a-methylene-y-butyrolactone which is a popular structure in many nature products. The chemoselectivity of reaction is quite well, no byproducts were observed and17compounds were synthesized. Meanwhile, compared to Zinc, the stereoselectivity of reaction that mediated by Indium was better; and water was used as solvent in the reaction, that’s more environment-friendly. Compared to the other method for the synthesis of a-methylene-y-butyrolactone, our ideal is more effective because the reaction is easier to operate, the conditions are more mild, yields are higher. There is no doubt that this method will be more and more used in the synthesis of the compounds that obtain the structure of a-methylene-y-butyrolactone.Then we synthesized (+)-8-Epigrosheimin from (JL)-Carvone and3-bromomethyl-5-H-furan-2-one after11steps, in which Barbier reaction and intramolecular ENE reaction were the key steps, and final yield reached45%. The synthesis proved that3-bromomethyl-5-H-furan-2-one is a useful compound for the synthesis of a-methylene-y-butyrolactone, formation of methylene and lactone improved the efficiency of synthesis remarkable. When we obtained the seven membered carbon ring, rigidity of lactone lead to enantioselective synthesis of final compound, which proved our strategy that formation of lactone was proceeded before carbon ring was right; during the reaction, two chiral centers in the lactone were precisely obtained because the chiral conduction from the starting compound. Compared to the methods that carbon ring was synthesized first and lactone was obtained later, our strategy got an advantage of chiral contral. The methods that have been reported to format a-methylene need certain steps and efficiency is poor, so our method provided a useful way for the synthesis of Epigrosheimin derivatives, which is good for the study of their bioactivitives and structure-activity relationship. At last,3-benzoyl-4-hydroxycoumarin derivatives that have a similar structure with sulcotrione were synthesized from4-hydroxycoumarin which is a lead compound. Herbicidal activities were investigated. The results showed that all compounds were active selectively against brassic campestris, nearly no activities against Echinochloa crusgalli, which means these compounds got the inhibition against dicotyledon but monocotyledon. Obviously, it goes the different way in the field of herbicidal activities, compared the commercial herbicide such as sulcotrione or mesotrione. It is quite necessary for us the find the3-benzoyl-4-hydroxycoumarin derivatives that obtain better Herbicidal activities against brassic campestris, after this we will investigate how these compounds work, so as to explode a new herbicide.