2-(4-氯苯氧基)-5-芳基-1,3,4-噁二唑化合物的合成

首先以 4 氯苯酚为原料,在无水K2CO3、丙酮和KI的作用下,与氯乙酸乙酯反应制得 4 氯苯氧乙酸乙酯(Ⅰ),收率 85. 7%。再以无水乙醇为溶剂,于 105~110℃,与w(水合肼) =80%的反应 8h,制得 4 -氯苯氧乙酰肼(Ⅱ),收率 78 .2%。然后该化合物在以碳酸钠作缚酸剂,温度 40℃的条件下分别与苯甲酰氯、4 甲氧基苯甲酰氯、3, 5- 二甲基苯甲酰氯、4 甲基苯甲酰氯和 4 氯苯甲酰氯反应,得相应的N,N′- 二酰基肼(Ⅲa~e),收率分别为 90 .2%、89 .3%、85. 1%、91. 4%和 86 .1%。最后Ⅲa~e分别在POCl3 作用下,脱水环化成了 2- (4 -氯苯氧基)-5 -芳基 1, 3, 4 -口恶二唑化合物(Ⅳa~e),收率分别为 87 .2%、89 .6%、86. 1%、88. 4%和 84.3%。通过元素分析,IR,1HNMR和MS对化合物Ⅳa~e的结构进行了表征。

Synthesis and Structural Characterization of 2-(4-Chlorophenoxy)-5-aryl-1,3,4-oxadiazoles

Ethyl 4-chlorophenoxyacetate(Ⅰ) was prepared in 85.7% yield by reaction of 4-chlorophenol with ethyl chloroacetate in the presence of anhydrous potassium carbonate,acetone and potassium iodide.Ⅰ reacted with 80% hydrazine hydrate for 8 h in anhydrous ethanol to give 4-chlorophenoxyacetylhydrazine(Ⅱ) in 78.2% yield.Then with Na_2CO_3 as acid acceptor at 40 ℃,Ⅱ reacted with(a) benzoyl chloride,(b)4-methoxybenzoyl chloride,(c)3,5-dimethylbenzoyl chloride,(d)4-methylbenzoyl chloride and (e)4-chlorobenzoyl chloride to give N,N′-diacylhydrazines (Ⅲa～e),respectively in 90.2%,89.3%,85.1%,91.4% and 86.1%.Finally,cyclodehydration of Ⅲa～e with POCl_3 afforded 2-(4-chlorophenoxy)-5-aryl-1,3,4-oxadiazoles (Ⅳa～e) in 87.2%,89.6%,86.1%,88.4% and 84.3% yield respectively.Structures of Ⅳa～e were confirmed by elementary analysis,IR,~1HNMR and MS spectroscopy.