Department of Chemistry & Biochemistry, Miami University, Oxford, Ohio 45056, United States.
Org Lett. 2020 Oct 2;22(19):7567-7571. doi: 10.1021/acs.orglett.0c02757. Epub 2020 Sep 22.
Transient changes in molecular geometry are key to the function of many important biochemical systems. Here, we show that diphenic acids undergo out-of-equilibrium changes in dihedral angle when reacted with a carbodiimide chemical fuel. Treatment of appropriately functionalized diphenic acids with EDC (-(3-(dimethylamino)propyl)-'-ethylcarbodiimide hydrochloride) yields the corresponding diphenic anhydrides, reducing the torsional angle about the biaryl bond by ∼45°, regardless of substitution. In the absence of steric resistance, the reaction is well-described by a simple mechanism; the resulting kinetic parameters can be used to derive important properties of the system, such as yields and lifetimes. The reaction tolerates steric hindrance ortho to the biaryl bond, although the competing formation of (transient) byproducts complicates quantitative analysis.
瞬态分子几何变化是许多重要生化系统功能的关键。在这里，我们表明二苯二酸与碳二亚胺化学燃料反应时，二面角会发生非平衡变化。用 EDC（-(3-(二甲基氨基)丙基)-'-乙基碳二亚胺盐酸盐）处理适当官能化的二苯二酸会生成相应的二苯二甲酸酐，使联苯键的扭转角减小约 45°，与取代无关。在没有空间位阻的情况下，反应可以很好地用一个简单的机制来描述；由此产生的动力学参数可用于推导系统的重要性质，如产率和寿命。该反应可以容忍联苯键邻位的空间位阻，尽管会形成（瞬态）副产物，使定量分析变得复杂。
