Department of Chemistry, Payame Noor University(PNU), P.O. Box: 19395-4697, Tehran,Iran.
Department of Chemistry, Firoozkooh Branch, Islamic Azad University, Firoozkooh,Iran.
Comb Chem High Throughput Screen. 2021;24(8):1261-1270. doi: 10.2174/1386207323666201001113545.
In this work, 1,3-oxazoles were generated using the multicomponent reaction of α-bromo ketones, alkyl (aryl) isothiocyanates, sodium hydride and Fe3O4 MNPs in the water at room temperature in good yields. The nanoparticles generated via the biosynthesis method have potential value in different purposes, such as organic synthesis.
To study the antioxidant ability of some synthesized thioxo-1,3-oxazoles, diphenyl-picrylhydrazine (DPPH) radical trapping and power of ferric reduction testes are employed. Among the studied thioxo-1,3-oxazoles, compound 4b have good power for radical trapping and reduction activity than the standard antioxidants such as BHT and TBHQ. In addition, the antimicrobial activity of some thioxo-1,3-oxazoles was studied, employing the disk diffusion test on Gram-positive bacteria and Gram-negative bacteria. The results of the disk diffusion test showed that compounds 4a, 4b, 4d and 4f prevented bacterial growth.
Without employing catalyst, these reactions have low yield and busy mixture. The synthesis of compound 4a as sample reaction has a similar yield in the presence of ZnO-NPs and Fe3O4 MNPs (entry 20 and entry 30), but the removal of catalyst from the mixture of reaction after the completion of the reaction is comfortable in the presence of Fe3O4 MNPs. Structures of compound 4a-4i are confirmed by IR, 1H NMR and 13C NMR mass spectra.
The reaction of α-bromo ketones, isothiocyanate and sodium hydride in the presence of the catalytic amount of FeO MNPs in water generates 1,3-oxazole derivatives in good yields. Some of the advantages of performing these reactions with the present procedure are to carry out these reactions in water as a green solvent and simple removal of catalyst.
在这项工作中，通过α-溴代酮、烷基（芳基）异硫氰酸酯、氢化钠和 Fe3O4 MNPs 的多组分反应，在室温下在水中生成 1,3-噁唑，产率良好。通过生物合成方法生成的纳米粒子在不同目的（如有机合成）中具有潜在价值。
为了研究一些合成的噻唑-1,3-噁唑的抗氧化能力，采用二苯基苦基肼（DPPH）自由基捕获和铁还原测试来研究。在所研究的噻唑-1,3-噁唑中，化合物 4b 具有良好的自由基捕获能力和还原活性，优于 BHT 和 TBHQ 等标准抗氧化剂。此外，还研究了一些噻唑-1,3-噁唑的抗菌活性，采用革兰氏阳性菌和革兰氏阴性菌的圆盘扩散试验。圆盘扩散试验的结果表明，化合物 4a、4b、4d 和 4f 阻止了细菌的生长。
在没有催化剂的情况下，这些反应产率低且混合物复杂。以化合物 4a 作为示例反应，在 ZnO-NPs 和 Fe3O4 MNPs 的存在下，反应具有相似的产率（条目 20 和条目 30），但在 Fe3O4 MNPs 的存在下，反应完成后从混合物中去除催化剂是舒适的。化合物 4a-4i 的结构通过 IR、1H NMR 和 13C NMR 质谱得到确认。
在 FeO MNPs 的催化量存在下，α-溴代酮、异硫氰酸酯和氢化钠在水中的反应以良好的产率生成 1,3-噁唑衍生物。使用本方法进行这些反应的一些优点是在水作为绿色溶剂中进行这些反应，并可简单去除催化剂。
