Catalysts and Organic Synthesis Research Laboratory, Department of Chemistry, Iran University of Science and Technology, Tehran, 16846-13114, Iran.
Sci Rep. 2022 Mar 18;12(1):4719. doi: 10.1038/s41598-022-07303-3.
In this study, a heterogeneous nanocatalyst is presented that is capable to efficiently catalyze the synthetic reactions of amide bond formation between the amino acids. This nanocatalyst which is named FeO@SiO/TABHA (TABHA stands for thio-aza-bicyclo-hepten amine), was composed of several layers that increased the surface area to be functionalized with 2-aminothiazole rings via Diels-Alder approach. Firstly, various analytic methods such as Fourier-transform infrared (FTIR) and energy-dispersive X-ray (EDX) spectroscopic methods, thermogravimetric analysis (TGA), electron microscopy (EM), and UV-vis diffuse reflectance spectroscopy (UV-DRS) have been used to characterize the desired structure of the FeO@SiO/TABHA catalyst. Afterward, the application of the presented catalytic system has been studied in the peptide bond formation reactions. Due to the existence of a magnetic core in the structure of the nanocatalyst, the nanoparticles (NPs) could be easily separated from the reaction medium by an external magnet. This special feature has been corroborated by the obtained results from vibrating-sample magnetometer (VSM) analysis that showed 24 emu g magnetic saturation for the catalytic system. Amazingly, a small amount of FeO@SiO/TABHA particles (0.2 g) has resulted in ca. 90% efficiency in catalyzing the peptide bond formation at ambient temperature, over 4 h. Also, this nanocatalyst has demonstrated an acceptable recycling ability, where ca. 76% catalytic performance has been observed after four recycles. Due to high convenience in the preparation, application, and recyclization processes, and also because of lower cost than the traditional coupling reagents (like TBTU), the presented catalytic system is recommended for the industrial utilization.
在这项研究中，提出了一种异质纳米催化剂，能够有效地催化氨基酸之间酰胺键形成的合成反应。这种纳米催化剂名为 FeO@SiO/TABHA（TABHA 代表硫代氮杂双环庚烯胺），由几层组成，通过 Diels-Alder 方法增加了表面积，使其能够功能化 2-氨基噻唑环。首先，使用傅里叶变换红外（FTIR）和能量色散 X 射线（EDX）光谱法、热重分析（TGA）、电子显微镜（EM）和紫外可见漫反射光谱（UV-DRS）等各种分析方法对 FeO@SiO/TABHA 催化剂的理想结构进行了表征。随后，研究了所提出的催化体系在肽键形成反应中的应用。由于纳米催化剂结构中存在磁性核，纳米粒子（NPs）可以通过外部磁铁从反应介质中轻易分离。这一特殊特性得到了振动样品磁强计（VSM）分析结果的证实，该结果表明催化体系的磁饱和为 24 emu g。令人惊讶的是，仅需少量的 FeO@SiO/TABHA 颗粒（0.2 g），即可在环境温度下、4 小时内实现约 90%的肽键形成催化效率。此外，该纳米催化剂还表现出可接受的循环能力，在经过四次循环后，仍能观察到约 76%的催化性能。由于其在制备、应用和再循环过程中的高便利性，以及成本低于传统偶联试剂（如 TBTU），因此推荐该催化体系用于工业应用。
