Synthesis Of Substituted 1,3-imidazolines And 1,3-Benzoxazines By Reaction Of N-aryl-N'-(2-Hydroxybenzyl) Ethylenediamine With Aldehydes

Nitrogen and oxygen heterocyclic compounds have a wide range of biological activities and are widely used in medicine,pesticides,chemicals,materials and other fields.The polyfunctional compounds containing an amino group and a hydroxyl one are important raw materials for synthesizing nitrogen and oxygen heterocyclic compounds.Therefore,this article mainly designed and synthesized a kind of hydroxyl-containing ethylenediamine compounds,and systematically studied its reaction with aldehydes,and synthesized1-?2-hydroxybenzyl?-2-hydrocarbyl-3-aryl-1,3-imidazolines and 2-aryl-3-?arylaminoethyl?-1,3-benzoxazines,and the structures of the compounds were confirmed by ¹H NMR,¹³C NMR and IR.At the same time,the synthesized compounds were tested for their fungicidal activity.?1?Under the action of triethylamine,a series of N-substituted 2-bromoacetamides A-1?A-10 were synthesized from bromoacetyl bromide,arylamine or benzylamine in an ice-water bath using CH₂Cl₂ as solvent.The yield was 69.5%?97.6%.Under the same conditions,2-bromo-N-?2-hydroxybenzyl?acetamide M was synthesized with o-hydroxybenzylamine and bromoacetyl bromide as starting materials,and the yield was76.8%.?2?The reaction of N-aryl-2-bromoacetamides A and o-hydroxybenzylamine with sodium carbonate as base in mixed solvent of DMF and THF?V:V=1:1?,at 65°C for 5 h,gave a series of N-aryl-2-?2-hydroxybenzylamino?acetamide B-1?B-10 in 38.4%⁷0.1%yields.?3?A series of N-aryl-N'-?2-hydroxybenzyl?ethylenediamines C-1^C-9 were synthesized in 71.6%⁸8.1%yields by reduction of N-aryl-2-?2-hydroxybenzylamino?acetamide B with LiAlH₄.The reaction conditions were as follows:the ratio of the amount of compound B to LiAlH₄ was 1:4.6,65°C,anhydrous THF as solvent,and the reaction time 3 h.?4?The reaction of N-aryl-N'-?2-hydroxybenzyl?ethylenediamine C with aldehyde was studied.It was found that N,N-azoacetal reaction occurred between the N-aryl-N'-?2-hydroxybenzyl?ethylenediamine C and aldehyde,affording a series of1-?2-hydroxybenzyl?-2-hydrocarbyl-3-aryl-1,3-imidazoline compounds Y-1^Y-26 in37.6%-93.2%yields.The reaction conditions were as follows:the molar ratio of compound C to aldehyde was 1:1.4,La?CF₃SO₃?₃?10%mol?,a mixture of CHCl₃ and cyclohexane?V:V=1:4?as solvent,80°C,3 h.A possible reaction mechanism for the formation of1,3-imidazoline was proposed.?5?In DMF/THF?V:V=1:1?,under the effect of sodium carbonate,reaction of2-bromo-N-?2-hydroxybenzyl?acetamide M and N-methylarylamine at 65°C for 10 h gave N-?2-hydroxybenzyl?-2-??N'-methyl-N'-aryl?amino?acetamides L-1^L-3 in 63.4%⁶9.1%yields.The maolar ratio of the reactants was:n?compound M?:n?N-methylarylamine?:n?Na₂CO₃?=1.0:1.2:1.5.?6?Reduction of N-?2-hydroxybenzyl?-2-??N'-methyl-N'-aryl?amino?acetamide Compound L by LiAlH₄ gave N-?2-hydroxybenzyl?-N'-?methylaryl?ethylenediamine compounds G-1^G-3 in 54.5%⁶7.2%yields.?7?Reaction of N-?2-hydroxybenzyl?-N'N'-?methylaryl?ethylenediamine G with aldehyde at 80°C for 7 hours in CHCl₃ and cyclohexane?V:V=1:4?with La?CF₃SO₃?₃?10 mol%?as catalyst,gave 3-?arylaminoethyl?-1,3-benzoxazine compounds X-1^X-9 in 59.8%⁷0.4%yields.The maolar ratio of?substituted ethylenediamine G?:n?aldehyde?=1:1.4.?8?The fungicidal activity of the synthesized compounds was determined,included N-aryl-2-?2-hydroxybenzylamino?acetamideB-5^B-10,1-?2-hydroxybenzyl?-2-?hydrocarbyl?-3-aryl-1,3-imidazolineY-1^Y-25,N-aryl-2-?2-hydroxybenzyl?ethylenediamine C-1^C-8,N-?2-hydroxybenzyl?-N',N'-?methylaryl?ethylenediamine G-1^G-3 and 2-aryl-3-??N'-methyl-N'-aryl?aminoethyl?-1,3-benzoxazine X-1^X-7,etc.Some compounds showed good activity,and the inhibition activity against Fusarium graminearum reached 94.1%,the inhibition rate of S.sclerotiorum reached 83.1%.