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Antibacterial Activity Of L-pyroglutamic Acid Sulfonyl Ester Derivatives And The Synthesis Of (+)-Alstonlarsine

Posted on:2024-04-08Degree:MasterType:Thesis
Country:ChinaCandidate:L K AiFull Text:PDF
GTID:2531307130970519Subject:Chemistry
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Botanical pesticides are one of third-generation pesticides sources,which have attracted great attention in recent years due to their advantages of easily degradable and pollution-free in nature.L-pyroglutamic acid and its derivatives derived from Disporopsis aspersa(HUA)ENGL.ex DIELS have antibacterial activity potential,and the monoterpene indole alkaloid(+)-alstonlarsine A derived from Alstonia scholaris has a specific structure and death associated protein related apoptotic kinase 2inhibitory activity.In this thesis,we mainly studied the sulfonyl ester derivatization of L-pyroglutamic acid and its anti-fungal activity against plant pathogens,as well as the synthesis of(+)-alstonlarsine A.Firstly,based on the principle of active splicing,25 novel L-pyroglutamic acid derivatives containing chiral sulfonyl ester structures were designed and synthesized by introducing chiral hydroxyl groups at the 4-position of L-pyroglutamic acid and connecting sulfonyl active groups to the hydroxyl groups.The inhibitory activity of these target compounds and intermediates against Pyricularia oryzae(SD),Fusarium graminearum(XC),Alternaria brassicae(BH),Valsa mali(PF),and Alternaria alternataria(YC)was tested using the mycelial growth rate method.The test results show that at concentration of 100μg/m L,all compounds had a certain inhibitory effect on five fungi,especially the inhibitory rates of compounds 2-8k,2-8l,2-9a,2-9l,and 2-9m against Fusarium graminearum were above 60.0%,higher than the commercially available control drug Hymexazol(35.1%),and close to Chlorothalonil(72.7%).Secondly,using commercial L-tryptophan(3-1)as the starting material,the key intermediate in the total synthesis of(+)-alstonlarsine A(1-30)was prepared on a scale of 3-24 grams through seven steps with a total yield of 34%.The entire synthesis route is concise and efficient,providing a material source and theoretical basis for promoting the total synthesis of(+)-alstonlarsine A.The key reactions of this route include:1)The intermediate 3-20 of L-tryptophan methyl ester undergoes indole2-position oxidation under the conditions of potassium bromide and potassium peroxymonosulfonate(Oxone),while removing the TBS protective group,thereby efficiently preparing compound 2-21;2)Weinreb amide 3-23 undergoes a Grignard addition reaction with Grignard reagent 3-5 to selectively synthesize Weinreb ketone3-24 with acetal side chains.
Keywords/Search Tags:Plant derived active natural products, L-pyroglutamic acid, Chiral sulfonyl ester, Antifungal activity, (+)-Alstonlarsine A, Intermediate synthesis
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