Synthesis And Biological Activity Of Magnolol Derivatives Containing Isopropanolamine Substructur

The natural magnolol belongs to dimeric phenylpropanol compounds.The magnolol and relevant derivatives bearing with a variety of biological activities such as antibacterial,insecticidal,antiviral,anti-inflammatory,antioxidant and anti-tumor activities.In this thesis,a series of magnolol compounds containing amino alcohols were synthesized by introducing amino alcohols into the skeleton of magnolol.The target compounds was characterized byhydrogen nuclear magnetic resonance spectroscopy（¹H NMR）,carbon nuclear magnetic resonance spectroscopy(¹³C NMR)and high resolution mass spectrometry（HRMS）.Therefore,the magnolol derivatives were synthesized in an effort to develop the“greener”agrochemicals,which possess certain properties such as safer to human,more friendly to environment and lower risk of resistance.The antibacterial activity in vitro of target compounds against Xanthomonas oryzae pv.oryzae（Xoo）,Xanthomonas axonopodis pv.citri（Xac）and Pseudomonas syringae pv.actinidiae（Psa）was determined by turbidimeter test method.The bioassay results suggested that most of the isopropanolamine magnolol derivatives containing the group of benzylamine,aliphatic amine displayed the good biological activity.Among them,compound a₁has an EC₅₀value of 1.53μg/m L against Xanthomonas oryzae pv.oryzae,compound a₉has an EC₅₀value of 2.50μg/m L against citrus canker,and compound a₈has an EC₅₀value of 1.97μg/m L against kiwi canker.Besides,the compound a₈were found to have the best antifungal activity,The EC₅₀value of compound a₈against Botrytis cinerea,Rhizoctonia solani and Capsicum wilt was 17.91,11.24,and 17.03μg/m L,respectively.The EC₅₀value of compound a₁₅against Sclerotinia sclerotiorum was 6.9μg/m L,and the EC₅₀value of compound a₁₆against Eggplant yellow wilt is 8.85μg/m L.The in vivo anti-Xoo activity（pot experiment）of compound a₂₈was carried out using leaf-cutting inoculation method.that the outcoming found that compound a₂₈exerted excellent curative activity（51.42%）for decreasing rice bacterial leaf blight than bismerthiazol（40.0%）and thiodiazole copper（40.8%）.a₂₈compared with bismerthiazol（39.47%）and thiodiazole copper（42.3%）,compound a₁demonstrated appropriate protective activity in vivo（49.73%）against rice bacterial leaf blight.Taken together,these series of compounds exerted good antibacterial activity in vitro and in vivo.Especially,compound a₁performed best antibacterial activy in vitro and vivo.Meanwhile,the compound a₁showed low phytotoxicity for rice plants.In summary,this class of compounds has good antibacterial activity.Among them,compound a1 not only has good in vitro activity against Xanthomonas oryzae pv.oryzae,but also has good live activity and low phytotoxicity.Therefore,the compound synthesized in this paper has certain research value.