Effects of N1 and N5 alkyl substituents on the stability of 6-oxoverdazyl radicals
作者:Matthew Bancerz、Michael K. Georges
DOI:10.1016/j.tetlet.2012.10.031
日期:2012.12
1,5-dialkyl-6-oxoverdazyl radicals with differing N1 and N5 substituents were synthesized as a means to observe the effects of different alkyl groups on the reactivity of verdazyl radicals towards disproportionation with a methyl group as the benchmark. Using previously described cycloaddition chemistry with verdazyl radical-derived azomethine imines via disproportionation, methyl acrylate was used
合成了一系列具有不同的N1和N5取代基的1,5-二烷基-6-氧杂二唑基团,作为观察不同烷基基团对Verdazyl基团歧化以甲基为基的反应性的影响的手段。使用先前描述的与通过Verdazation衍生自Verdazyl自由基的偶氮甲亚胺的环加成化学,丙烯酸甲酯用于原位捕获歧化产物,以便观察此过程中N1对N5的位选择性。出乎意料的是,在大多数情况下,与甲基相比,较大的烷基被证明具有更高的反应性,这可以解释为氢歧化过程中氢原子的抽象所涉及的C–H键的削弱。这些结果与较大的空间体积通常会使自由基的反应性较低的想法形成对比。