Hellrung Bruno, Kamdzhilov Yavor, Schwörer Markus, Wirz Jakob
Departement Chemie der Universität Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland.
J Am Chem Soc. 2005 Jun 29;127(25):8934-5. doi: 10.1021/ja052300s.
The mechanism for the photoinduced release of glycolic acid from its 2-nitrobenzyl ether was reinvestigated. The pH-dependent rate constants of the thermal reactions initiated by irradiation are similar to those reported previously for 2-nitrobenzyl methyl ether. A hemiacetal intermediate that limits the release rate of glycolic acid at pH values </=7 was identified by time-resolved IR and UV measurements. Furthermore, 2-(2'-nitrosophenyl)-1,3-dioxolan-4-one, a long-lived intermediate formed by intramolecular trapping of the aci-tautomer, was observed and characterized.
对光诱导乙醇酸从其2-硝基苄基醚释放的机制进行了重新研究。辐照引发的热反应的pH依赖性速率常数与先前报道的2-硝基苄基甲基醚的速率常数相似。通过时间分辨红外和紫外测量确定了一种半缩醛中间体，该中间体在pH值≤7时限制了乙醇酸的释放速率。此外，还观察并表征了2-(2'-亚硝基苯基)-1,3-二氧戊环-4-酮，这是一种由酸式互变异构体的分子内捕获形成的长寿命中间体。
