The Construction Of C=N Bond From Aromatic Aldehyde And Ammonium Salt Via Iron-Catalyzed To Synthesis 1,3,5-Triazines

1,3,5-triazine is the important structural motif in natural products,bioactive molecules,and advanced functional materials due to its special C=N ring structure.1,35-triazine is also valuable intermediate for the synthesis of various organometallic frameworks and supramolecules.Therefore,direct and simple construction of1,3,5-triazine structure is an important and popular research field.Although significant results have been achieved in the methods of synthesizing 1,3,5-triazine compounds,these synthetic methods generally use nitriles,amidines,organic amidine salts,etc.as a single nitrogen-containing source to construct symmetric or asymmetric1,3,5-triazine compounds.However,most of them have the disadvantages of harsh reaction conditions,complicated operation,and poor substrate applicability.Ammonium salts are common inorganic molecules widely used to provide nitrogen in synthesizing nitrogen-containing heterocyclic compounds.Among them ammonium iodide often acts as a mediator and promoter in the reaction process.However,the synthesis of nitrogen-containing heterocyclic compounds by supplying a nitrogen source with ammoniums salt are mostly synthesis of heterocyc lic compounds containing one nitrogen or two nitrogens.The method for synthesizing a heterocyclic compound containing three nitrogens from ammonium salts as a nitrogen source is never reported.Therefore,it is necessary to develop a method for directly synthesizing 1,3,5-triazine compounds by directly supplying all nitrogen sources with ammonium salts.The specific research contents are as follows:(1)the construction of 1,3,5-triazine from different nitrogen sources and the synthesis of 1,3,5-triazine compounds from different method were systematically summarized and compared.Meanwhile,the background,theoretical significance and specific experimental contents of this work were briefly introduced.(2)the reactions of aromatic aromatic aldehyde and am monium salts and different aromatic aldehyde and ammonium salts to construct symmetric and asymmetric 1,3,5-triazine compounds were investigated in detail.The optimal reaction conditions were obtained to synthesize symmetrical 1,3,5-triazine compounds:benzaldehyde(0.5 mmol),ammonium iodide(0.5 mmol),Fe Cl ₃(20 mol%),toluene(2.0 m L),130 ^oC,15 h.Synthesis of asymmetric 1,3,5-triazine compounds:benzaldehyde(0.3 mmol),p-tolualdehyde(0.2 mol),ammonium iodide(0.5 mmol),Fe Cl₃(20 mol%),toluene(2.0 m L),130 ^oC,15 h.The experimental results show that the reaction shows good substrate suitability for aromatic aldehydes with different substituents,and the target product can be obtained with moderate to good yields.The corresponding product can also be obtained for the mixed aldehyde reaction.(3)The reaction mechanism of aromatic aldehyde and ammonium iodide to construct 1,3,5-triazine compounds was systematically studied.Through designing control and monitor experiments,combining related liter ature,a possible reaction mechanism was proposed for the reaction process.