Synthesis,Characterization,Biological Activity And Structure Activity Relationship Of Nicotine Salts

As the main biologically active ingredient in tobacco plants,nicotine has important medicinal value and is widely used in biology,medicine,pesticides and other fields,especially in the field of pesticides,but the resistance of pests and diseases to drugs is also a kind of inevitable phenomenon.In recent years,the development and utilization of nicotine salts as biologically active drugs have attracted people’s attention.Based on this,this paper uses the chemical characteristics of nicotine,reasonably selects organic acids and halogenated hydrocarbon compounds,solidifies nicotine through salt-forming reaction to improve its stability,and evaluates the biological activity of nicotine salts through antibacterial and insecticidal experiments Combining theoretical calculations to explore the structure-activity relationship between its biological activity and structure,the main contents are as follows:First,series Ⅰ nicotine salts(Ⅰa-f)and series Ⅱ nicotine salts(Ⅱa-c)were synthesized by acid-base reaction and quaternary ammonium reaction with organic acids(benzoic acid,phthalic acid,salicylic acid,p-Acetylamino benzoic acid,oxalic acid and tartaric acid)and haloalkane(bromooctane,1,6-dibromohexane and 1,10-dibromodecane)respectively.The molecular structure of nicotine salts was characterized by hydrogen spectrum,carbon spectrum and X-ray single crystal diffraction.The contribution of molecular interactions to crystal stacking was studied by Hirshfeld surface analysis.Secondly,the insecticidal activity of series Ⅰ nicotine salts was tested by the method of loading toxic leaves.Among series Ⅰ nicotine salts,nicotine phthalate(Ⅰb)had the best insecticidal effect on psyllid adults at 120 h.It was found that nicotine benzoate(Ⅰa)and nicotine o-hydroxybenzoate(Ⅰc)had better inhibitory effect on fungi,and the inhibitory rate against Fusarium graminearum and Apple anthrax was higher than that of the standard drug clonidamine.The antibacterial activity of series Ⅱ nicotine salt was higher than that of single quaternary ammonium nicotine salt.Finally,the molecular docking technique was used to simulate the action mode of series Ⅱ nicotine salts and polygalacturonase,and the structure-activity relationship of nicotine salts on polygalacturonase inhibition was discussed.The density functional theory(DFT)method was used to study the structure optimization,frontier orbit and Mulliken charge of nicotine salts(Ⅰb and Ⅰd).Based on theoretical calculation,the relationship between biological activity and structure of some nicotine salts was comprehensively analyzed,providing a certain reference for the later design and development of new nicotine salt drugs.