Baily Philip T, Del Castillo H Patricio, Vinales Irodiel, Urbay Juan E M, Paez Aurelio, Weaver Matthew R, Iturralde Roberto, Estevao Igor L, Jankuru Sohan R, Almeida Igor C, Li Chunqiang, Dirk Carl W, Michael Katja
Department of Chemistry and Biochemistry, University of Texas at El Paso, El Paso, Texas 79968, United States.
Department of Metallurgical, Materials and Biomedical Engineering, University of Texas at El Paso, El Paso, Texas 79968, United States.
ACS Omega. 2023 Feb 27;8(10):9486-9498. doi: 10.1021/acsomega.2c08184. eCollection 2023 Mar 14.
The photolytic properties of -acyl-7-nitroindolines make these compounds attractive as photocleavable protecting groups and "caged" compounds for the light-induced release ("uncaging") of biologically active compounds and as acylating reagents under neutral conditions. However, the synthesis of -acyl-7-nitroindolines usually requires multiple steps, and the direct acylation of 7-nitroindolines can be quite challenging. 7-Nitroindolines with other types of -carbonyl-containing groups may also be photoreactive and could potentially be better accessible. Here we demonstrate the short and efficient synthesis of 5-bromo-7-nitroindoline--thiocarbamates, a new class of photoreactive compounds, and the study of some of their photochemical and photophysical properties. Using 5-bromo-7-nitroindoline--ethylthiocarbamate as a model compound, we show that it can undergo one-photon and two-photon photolysis at 350 and 710 nm, respectively. Our experimental data and quantum chemistry calculations support a photolysis pathway that differs from photolysis pathways previously reported for -acyl-7-nitroindolines. The photolysis with 350 nm light results in 5-bromo-7-nitrosoindoline, which is in equilibrium with its dimeric form(s), as supported by experiment and theory. This study expands the scope of photoreactive 7-nitroindoline derivatives and informs the development of novel photocleavable compounds.
β-酰基-7-硝基吲哚啉的光解特性使这些化合物作为可光裂解的保护基团以及用于生物活性化合物光诱导释放（“解笼”）的“笼形”化合物，以及在中性条件下作为酰化试剂具有吸引力。然而，β-酰基-7-硝基吲哚啉的合成通常需要多步反应，并且7-硝基吲哚啉的直接酰化可能具有相当大的挑战性。带有其他类型含β-羰基基团的7-硝基吲哚啉也可能具有光反应性，并且可能更容易获得。在此，我们展示了新型光反应性化合物5-溴-7-硝基吲哚啉-β-硫代氨基甲酸盐的简短高效合成方法，并对其一些光化学和光物理性质进行了研究。以5-溴-7-硝基吲哚啉-β-乙基硫代氨基甲酸盐作为模型化合物，我们表明它分别在350和710nm处可发生单光子和双光子光解。我们的实验数据和量子化学计算支持了一种与先前报道的β-酰基-7-硝基吲哚啉的光解途径不同的光解途径。350nm光的光解产生5-溴-7-亚硝基吲哚啉，实验和理论均支持其与其二聚体形式处于平衡状态。这项研究扩展了光反应性7-硝基吲哚啉衍生物的范围，并为新型可光裂解化合物的开发提供了信息。
