Catalysts and Organic Synthesis Research Laboratory, Department of Chemistry, Iran University of Science and Technology, Tehran 16846-13114, Iran.
Catalysts and Organic Synthesis Research Laboratory, Department of Chemistry, Iran University of Science and Technology, Tehran 16846-13114, Iran.
Ultrason Sonochem. 2019 Dec;59:104737. doi: 10.1016/j.ultsonch.2019.104737. Epub 2019 Aug 19.
A convenient strategy for synthesis of the various derivatives of 1,4-dihydropyridine (1,4-DHP), as one of the most important pharmaceutical compounds, is presented in this study. For this purpose, firstly, magnetic iron oxide nanoparticles (FeO NPs) were fabricated and suitably coated by silica network (SiO) and trimethoxy vinylsilane (TMVS). Then, their surfaces were well functionalized with pyrimidine-2,4-diamine (PDA) as the main active sites for catalyzing the synthesis reactions. In this regard, the performance of three different methods including reflux, microwave (MW) and ultrasound wave (USW) irradiations have been comparatively monitored via studying various analyses on the fabricated nanocatalyst (FeO/SiO-PDA). Concisely, high efficiency of the USW irradiation (in an ultrasound cleaning bath with a frequency of 50 kHz and power of 250 W/L) has been well proven through the investigation of the main factors such as excellent surface-functionalization, core/shell structure conservation, particle uniformity, close size distribution of the particles, and great inhibition of the particle aggregation. Then, the effectiveness of the USW irradiation as a promising co-catalyst agent has been clearly demonstrated in the 1,4-DHP synthesis reactions. It has been concluded that the USW could provide more appropriate conditions for activation of the catalytic sites of FeO/SiO-PDA NPs. However, high reaction yields (89%) have been obtained in the short reaction times (10 min) due to the substantial synergistic effect between the presented nanocatalyst and USW.
本研究提出了一种方便的合成 1,4-二氢吡啶（1,4-DHP）各种衍生物的策略，1,4-DHP 是最重要的药物化合物之一。为此，首先制备了磁性氧化铁纳米粒子（FeO NPs），并通过硅网络（SiO）和三甲氧基乙烯基硅烷（TMVS）进行适当的包覆。然后，它们的表面用嘧啶-2,4-二胺（PDA）进行了很好的功能化，作为催化合成反应的主要活性位点。在这方面，通过研究制备的纳米催化剂（FeO/SiO-PDA）的各种分析，比较监测了三种不同方法（回流、微波（MW）和超声波（USW）辐射）的性能。简而言之，通过研究出色的表面功能化、核/壳结构保持、颗粒均匀性、颗粒接近的尺寸分布以及对颗粒聚集的强烈抑制等主要因素，证明了 USW 辐射的高效率（在频率为 50 kHz、功率为 250 W/L 的超声波清洗浴中）。然后，USW 作为一种有前途的共催化剂在 1,4-DHP 合成反应中的有效性得到了明确证明。结论是，USW 可以为 FeO/SiO-PDA NPs 的催化活性位点的激活提供更合适的条件。然而，由于提出的纳米催化剂和 USW 之间的实质性协同效应，在短反应时间（10 分钟）内获得了高反应收率（89%）。
