2-(4-硝基苯氧甲基)-5-芳基-1,3,4-噁二唑的合成与结构表征

Synthesis and Structural Characterization of 2-(4-nitrophenoxy methyl)-5-aryl-1,3,4-oxadiazole

以4-硝基苯酚为原料,在无水K2CO3和乙腈的作用下,与氯乙酸乙酯反应制得4-硝基苯氧乙酸乙酯,收率90.1%;再以无水乙醇为溶剂,于80-85℃,与w(水合肼)=85%的反应3 h,制得4-硝基苯氧乙酰肼,收率79.7%;然后该化合物以吡啶作缚酸剂,三氯氧磷作酰氯化试剂,室温条件下与苯甲酸反应,制得N,N′-二酰基肼,收率90.6%;最后N,N′-二酰基肼在三氯氧磷作用下,脱水环化合成了最终产物2-(4-硝基苯氧甲基)-5-苯基-1,3,4-噁二唑,收率88.2%.通过IR,1H NMR,13C NMR对上述化合物的结构进行了表征.

Ethyl 4-nitrophenoxyacetate is prepared in 90.1% yield by reaction of 4-nitrophenol with ethyl chloroacetate in the presence of anhydrous potassium carbonate and acetonitrile. Ethyl 4-nitrophenoxyacetate reacts with 85% hydrazine hydrate for 3h in anhydrous ethanol to give 4-nitrophenoxyacetylhydrazine in 79.7% yield. Then with pyridine as acid acceptor at 25 ℃, 4-nitrophenoxyacetylhydrazine reacts with benzoic acid to give N, N＇-diacylhydrazine in 90.6% yield. Finally, cyclodehydration of N, N＇-diacylhydrazine with POC13 produces 2-（4-nitrophenoxy）-5-aryl-1, 3, 4-oxadiazole in 88.2% yield. The structures of these compounds are characterized by IR,^1H NMR and ^13C NMR spectroscopy.