三苯基膦/NBS协同促进酮肟贝克曼重排反应——酰胺类化合物的合成研究

Triphenylphosphine/NBS-Catalyzed Beckmann Rearrangement of Ketoximes into Amides

Beckmann重排反应在有机合成反应中具有十分重要的价值,但由于苛刻的反应条件、催化剂的难制备和毒性等,严重制约该反应的应用。本文提供一种催化酮肟Beckmann重排反应的新型催化体系,以Ph 3 P/NBS(N-溴代丁二酰亚胺,NBS)协同催化酮肟发生Beckmann重排合成一系列酰胺,对制备得到的化合物进行表征和测试,并给出可能的反应机理。实验结果表明,本文方法能高效、高收率地合成一系列酰胺(产率76%~99%),制备得到的4-苯基二苯甲酮类酰胺和4-硝基二苯甲酮类酰胺有较大的Stoke’s位移(分别是118和151 nm),说明通过调节芳基上的取代基,可以有效地调整该类化合物分子极性方向,有利于荧光增大分子内的电荷转移效应,增大Stoke’s位移,为该类化合物在荧光探针方面的应用奠定了理论基础。本文方法具有腐蚀性低、反应产率高、可以放大、反应时间短以及后处理简单等优点,为Beckmann重排反应的推广应用提供了理论依据。

A Beckmann rearrangement of ketoximes reaction using triphenylphosphine/NBS as an effective catalyst in acetonitrile is developed.The results indicate that conversion of oximes to amides can reach excellent yields(76%-99%yield)under mild reaction conditions.There are many merits about this method,such as low corrosion,high yields,large-scale preparation,environmental friendliness,simple work-up procedure,and short reaction time.The reaction mechanism is also proposed.The absorption and emission spectrum characteristics of the compounds are also examined.The N-phenyl-[1,1′-biphenyl]-4-carboxamide and 4-nitro-N-phenylbenzamide have a large Stokes shifts of 118,151 nm,respectively.The results indicate that altering the substitution of aromatic group can be an effective means to regulate the Stoke’s shift.