Ghasemzadeh Mohammad A, Abdollahi-Basir Mohammad H, Elyasi Zahra
Department of Chemistry, Qom Branch, Islamic Azad University, Qom, Iran.
Comb Chem High Throughput Screen. 2018;21(4):271-280. doi: 10.2174/1386207321666180330164942.
The multi-component condensation of benzil, primary amines, ammonium acetate and various aldehydes was efficiently catalyzed using cobalt oxide nanoparticles under ultrasonic irradiation. This approach describes an effective and facile method for the synthesis of some novel 1,2,4,5-tetrasubstituted imidazole derivatives with several advantages such as high yields and short reaction times and reusability of the catalyst. Moreover, the prepared heterocyclic compounds showed high antibacterial activity against some pathogenic strains.
The facile and efficient approaches for the preparation of Co3O4 nanoparticles were carried out by one step method. The synthesized heterogeneous nanocatalyst was characterized by spectroscopic analysis including EDX, FE-SEM, VSM, XRD and FT-IR analysis. The as-synthesized cobalt oxide nanoparticles showed paramagnetic behaviour in magnetic field. In addition, the catalytic influence of the nanocatalyst was examined in the one-pot reaction of primary amines, benzil, ammonium acetate and diverse aromatic aldehydes under ultrasonic irradiation. All of the 1,2,4,5-tetrasubstituted imidazoles were investigated and checked with m.p., 1H NMR, 13C NMR and FT-IR spectroscopy techniques. The antibacterial properties of the heterocycles were evaluated in vitro by the disk diffusion against pathogenic strains such as Escherichia coli (EC), Bacillus subtillis (BS), Staphylococcus aureus (SA), Salmonellatyphi (ST) and Shigella dysentrae (SD) species.
In this research cobalt oxide nanostructure was used as a robust and green catalyst in the some novel imidazoles. The average particle size measured from the FE-SEM image is found to be 20-30 nm which confirmed to the obtained results from XRD pattern. Various electron-donating and electron-withdrawing aryl aldehydes were efficiently reacted in the presence of Co3O4 nanoparticles. The role of the catalyst as a Lewis acid is promoting the reactions with the increase in the electrophilicity of the carbonyl and double band groups. To investigate the reusability of the catalyst, the model study was repeated using recovered cobalt oxide nanoparticles. The results showed that the nanocatalyst could be reused for five times with a minimal loss of its activity.
We have developed an efficient and environmentally friendly method for the synthesis of some tetrasubstituted imidazoles via three-component reaction of benzil, primary amines, ammonium acetate and various aldehydes using Co3O4 NPs. The present approach suggests different benefits such as: excellent yields, short reaction times, simple workup procedure and recyclability of the magnetic nanocatalyst. The prepared 1,2,4,5-tetrasubstituted imidazoles revealed high antibacterial activities and can be useful in many biomedical applications.
在超声辐射下，使用氧化钴纳米颗粒有效地催化了联苯甲酰、伯胺、醋酸铵和各种醛的多组分缩合反应。该方法描述了一种有效且简便的合成一些新型1,2,4,5-四取代咪唑衍生物的方法，具有产率高、反应时间短和催化剂可重复使用等优点。此外，所制备的杂环化合物对一些致病菌株表现出高抗菌活性。
通过一步法进行了制备Co3O4纳米颗粒的简便高效方法。通过包括能谱分析（EDX）、场发射扫描电子显微镜（FE-SEM）、振动样品磁强计（VSM）、X射线衍射（XRD）和傅里叶变换红外光谱（FT-IR）分析在内的光谱分析对合成的多相纳米催化剂进行了表征。所合成的氧化钴纳米颗粒在磁场中表现出顺磁行为。此外，在超声辐射下，研究了纳米催化剂在伯胺、联苯甲酰、醋酸铵和各种芳香醛的一锅反应中的催化影响。对所有的1,2,4,5-四取代咪唑进行了研究，并用熔点、1H核磁共振、13C核磁共振和FT-IR光谱技术进行了检测。通过纸片扩散法对杂环化合物对致病菌株如大肠杆菌（EC）、枯草芽孢杆菌（BS）、金黄色葡萄球菌（SA）、伤寒沙门氏菌（ST）和痢疾志贺氏菌（SD）的抗菌性能进行了体外评估。
在本研究中，氧化钴纳米结构被用作一些新型咪唑中的一种强大且绿色的催化剂。从FE-SEM图像测量的平均粒径为20 - 30 nm，这与XRD图谱获得的结果一致。在Co3O4纳米颗粒存在下，各种供电子和吸电子芳醛有效地发生了反应。催化剂作为路易斯酸的作用是随着羰基和双键基团亲电性的增加促进反应。为了研究催化剂的可重复使用性，使用回收的氧化钴纳米颗粒重复了模型研究。结果表明，纳米催化剂可以重复使用五次，其活性损失最小。
我们开发了一种高效且环境友好的方法，通过使用Co3O4纳米颗粒，经由联苯甲酰、伯胺、醋酸铵和各种醛的三组分反应合成一些四取代咪唑。本方法具有不同的优点，如：产率优异、反应时间短、后处理程序简单以及磁性纳米催化剂的可回收性。所制备的1,2,4,5-四取代咪唑显示出高抗菌活性，可用于许多生物医学应用。
