微波促进氟代脱硝合成含氟芳香族化合物

SYNTHESIS OF FLUOROAROMATICS VIA FLUORODENITRATION PROMOTED BY MICROWAVE

在微波加热下,以硝基芳烃为反应底物,以喷雾干燥氟化钾为氟化试剂,以四苯基溴化鏻-四乙二醇二甲醚为催化剂,以邻苯二甲酰氯为NO2-捕捉剂,在二甲亚砜溶剂中经氟代脱硝反应合成一系列含氟芳香族化合物。该反应反应时间短(10min～2h),氟代产物收率和选择性分别可达20.1%～91.9%和46.1%～94.0%,均好于相同条件下常规加热的收率和选择性。

Fluorodenitration is one of the efficient methods for the preparation of fluoroaromatics. Nevertheless, the traditional fluorodenitration reaction needs long reaction time and inevitably companies with serious by-reactions. So , microwave was applied to promote greatly the fluorodenitration reaction rate, improve the yields and also inhibit by-reactions. With nitroaromatics as substrate, spray drying potassium fluoride （SD-KF） as fluorinating agent, tetraphenyl phosphonium bromide-tetraethylene glycol dimethyl ether（Ph4 PBr-TEG-Me2） as catalyst, phthalic chloride （PDC） as trapping agent of NO2 , the mixture being stirred at refluxing under microwave irradiation for 10 min- 2 h in dimethyl sulfoxide （DMSO） resulted in 46.1%- 94.0% selectivities and 20. 1%-91.9% yields, which are higher than those with traditional methods under the same conditions. The reaction time could be shortened at least by 50% comparing with conventional heating.