微波辅助氯二氟乙酸钠促进2-羟基苯乙酮肟一锅制备苯并异噁唑反应研究

Microwave-assisted One-pot Conversion of 1-(2-Hydroxyphenyl)ethanone Oximes to Benzo[d]isoxazoles Catalyzed by Sodium 2-Chloro-2,2-difluoroacetate

摘要:

在微波辐射条件下，以氯二氟乙酸钠为促进剂，实现2-羟基苯乙酮肟一锅法制备苯并异噁唑反应。考察了不同促进剂及用量、溶剂、碱、温度以及微波功率对反应的影响。确定最优反应条件为：n(2-羟基苯乙酮肟)：n(氯二氟乙酸钠)：n(碳酸钾) = 1：1.5：1.5，溶剂为N,N-二甲基乙酰胺(2-羟基苯乙酮肟的浓度为1 mol/L)，微波功率为300 W，反应温度为85 ℃，反应时间为35 min。在最优条件下，以64%~93%的收率得到8种含不同取代基的苯并异噁唑类化合物。用1HNMR和MS对目标产物的结构进行了表征。

Abstract:

One-pot conversion of 1-(2-hydroxyphenyl)ethanone oximes to benzo[d]isoxazoles was achieved under microwave-assisted condition and catalyzed with sodium 2-chloro-2,2-difluoroacetate (SCDA). The effects of solvent, the amount of iodine, microwave power and reaction temperature on the reaction were considered. The optimized reaction conditions are: n(oximes):n(SCDA): n(K2CO3) = 1:1.5:1.5, in N,N-dimethylacetamide (1 mol/L for oximes), microwave power 300 W, reaction temperature 85 ℃, reaction time 35 min. Eight benzo[d]isoxazoles with different substituent groups were synthesized in 64%~93% yields under the optimized reaction conditions. The structures of all products were confirmed by the corresponding nuclear magnetic resonance spectrum (1HNMR) and mass spectrum (MS).