An exploratory and mechanistic study of the defluorination of an (aminofluorophenyl)oxazolidinone: SN1(Ar*) vs. SR+N1(Ar*) mechanism
作者:Elisa Fasani、Fedele Tilocca、Stefano Protti、Daniele Merli、Angelo Albini
DOI:10.1039/b812372a
日期:——
nucleophile such as pyrrole. The rationalization is supported by the study of some related molecules. Thus, the only photochemical reaction from the non fluorinated analogue of linezolid (that ionizes just as 1) is an inefficient degradation of the morpholine chain (Phi 0.001), while a simple model such as N-(2-fluorophenyl)morpholine undergoes photosolvolysis in water and is not trapped by pyrrole.
在某些产品中,吗啉代氟苯基恶唑烷酮1(抗菌药物利奈唑胺)在水中照射后会发生还原性脱氟(Phi 0.33),其中一些产品会同时发生吗啉侧链的氧化降解。在氯化物,碘化物和吡咯的存在下,氟被这些基团取代(在位置2处有吡咯)。脱氟在甲醇中效率较低,主要导致还原(Phi 0.053)。可以通过两种不同的机制来容纳这些数据。CF键杂合以产生苯基阳离子[S(N)1(Ar *)],或电离以产生自由基阳离子[S(R(+)N)1(Ar *)]。已收集稳态和时间解析数据来澄清此问题。发现实际上1的电离是有效的,并且是从单重态开始的,但不会导致不可逆转的变化。相反,三重态(3)1(在甲醇中的寿命为0.5微米,在水中为<0.1微米)会碎裂,并给出相应的三重态苯基阳离子。最后一个中间体很好地解释了所观察到的氢在分子间(从溶剂中还原时)和分子内(从吗啉基团)以及从带电阴离子或中性π亲核试剂(如吡咯)中析氢。合理化得到一