Synthesis And Fungicidal Activity Of Ureido-substituted 1,3-benzoxazines And 1,4-benzoxazinoimidazolines

Recently,heterocyclic compounds are one of the hotspots in the development of new pesticides and drugs.Benzoxazines,imidazoles/imidazoldines and urea compounds have a wide range of biological activities,and have played an important role in the discovery of new drug and pesticide,and have received increasing attention.In this thesis,a series of novel structure of ureido-substituted 1,3-benzoxazines and1,4-benzoxazinone imidazolidines was designed and synthesized,and their fungicidal activities were studied.The structures of the synthesized compounds were characterized by ¹H NMR,¹³C NMR and IR.?1?Using a"one-pot method",N,N'-diethylformyl chloride reacted with p-phenylenediamine?m-phenylenediamine?to form N-ureidophenylamine compounds I under the action of triethylamine.Reaction with salicylaldehyde or substituted salicylaldehyde to obtain Schiff bases II followed by reduction with NaBH₄ to give a series of arylaminophenyl ureas III.The reaction conditions are:the reaction temperature of the formation of compound I being 40°C,time 12h,CH₂Cl₂as solvent,triethylamine as acid binding agent,the ratio of p-phenylenediamine and N,N'-diethylformyl chloride is 1:1.8;the reaction temperature of the formation of Schiff base II being 60°C,time 5h,the ratio of p-phenylenediamine to salicylaldehyde being 1:3,and the yields was 57.5-64.0%.?2?Using THF as solvent,lanthanum triflate La?CF₃SO₃?₃?10 mol%?as catalyst,arylaminophenylurea III reacted with aldehydes at 65°C to give a series of ureido-substituted 1,3-benzoxazines in yields of 40⁷1%.?3?A series of bromoacetamides V-1^V-11 were synthesized in 79.6%-97.4%yields by reactions of bromoacetyl bromide and aniline in the presence of triethylamine in CH₂Cl₂.?4?In a mixed solvent of DMF and THF?V:V=1:2?,potassium carbonate as base,a series of N-aryl-2-?2-hydroxyphenylamino?acetamides VI-1^VI-11 were synthesized in 53.5%⁸4.4%yields by reactions of bromoacetamide V and o-aminophenol?the ratio of n?V?:n?o-aminophenol?:n?K₂CO₃?=1.0:1.2:1.4?at65°C.?5?A series of 2-?arylaminoethylamino?phenol VII-1^VII-11 was synthesized in 46.7%⁸5.0%yields by reduction of N-aryl-2-?2-hydroxyphenylamino?acetamide compound VI with LiAlH₄.?6?A series of 1,4-benzoxazinonoimidazolidines IX-1^IX-9 were synthesized by reactions of 2-??arylamino?ethylamino?phenols VII and ethyl glyoxylate under the catalysis of DABCO.The reaction conditions are as follows:the ratio of2-??arylamino?ethylamino?phenol to ethyl glyoxylate being 1:1.8,toluene as solvent,the catalyst DABCO?30 mol%?,temperature 100°C,time 19 h.The yields were41.1%⁵6.9%.At the same time,the case of using Et₃N?30 mol%?as catalyst was also investigated.The yields did not vary significantly for both cases of DABCO and Et₃N.?7?The synthesized compounds were tested for fungicidal activity.The results showed that some compounds showed good activity.Among them,compound III-1showed excellent activity against both Sclerotinia sclerotiorum and Rhizoctonia solani,and the inhibition rates were 94.6%and 94.2%,respectively.The inhibition rate of compound III-2 against Sclerotinia sclerotiorum and Fusarium graminearum was 75.6%.The inhibition rates of compounds IV-5 and IV-9 against Fusarium graminearum were 81.6%and 70.5%,respectively.The inhibition rates of compounds VI-4 and VI-11 against Fusarium graminearum were 74.5%,and the inhibition rates of compounds VI-2 and VI-8 were71.3%.The inhibition rates of compounds VI-10 and VI-11 against Sclerotinia sclerotiorum were 74.3%and 72.5%,respectively.The inhibition rate of VII-5 against Sclerotinia sclerotiorum was as high as97.7%,and the inhibition rate against Botrytis cinerea was also 73.6%.Compound VII-4 inhibited Phytophthora infestans by 86.7%.Furthermore,for Sclerotinia sclerotiorum,Botrytis cinerea,and Rhizoctonia solani,when a substituent is at the4-position of the benzene ring,the activity of an electron-withdrawing group is higher than that of an electron-donating group or H atom.Compounds IX-1,IX-2,IX-7 and IX-8 have good fungicdial activity against Sclerotinia sclerotiorum,and the inhibition rates are 63.6%,72.5%,62.5%and 63.6%,respectively.Compounds IX-2 and IX-9 had good fungicdial activity against Phytophthora,and the inhibition rate was 73.3%.In addition,for Sclerotinia sclerotiorum,when the substituent is at the 4-position on the phenyl ring,the order of fungicdial activity is CH₃>CH₂CH₃>H>Cl>CH₃O.