Background: One of the principal factors in the field of research in green chemistry is to drive chemical reactions using ultrasonication as a versatile synthetic tool. Moreover, nanostructured metal salts occupy an important position as low cost, efficient, heterogeneous, and green catalysts in chemical reactions. Pyrimidine has also acquired significance because it is a core structure in a variety of natural and non-natural agents, many of which display versatile biological activities and medical applications.

Objective: The aim of this study was to explore the role of nickel(II) chromite nanoparticles (NiCr₂O₄ NPs) as a green and recyclable catalyst for the synthesis of 2,4-diamino-6-arylpyrimidine- 5-yl cyanides under ultrasonic radiation.

Methods: A direct cyclocondensation reaction of guanidine nitrate, aromatic aldehydes, and malononitrile was performed using NiCr₂O₄ NPs as an effective heterogeneous catalyst under ultrasonic radiation at room temperature conditions to prepare 2,4-diamino-6-aryl-pyrimidine-5-yl cyanides in high yields. The described catalyst was prepared successfully according to a simple hydrothermal route and fully characterized by the X-Ray diffraction (XRD) technique, dispersive energy X-Ray (EDS) analysis, scanning electron microscopy (SEM), and dynamic light scattering (DLS).

Results: A number of 2,4-diamino-6-aryl-pyrimidine-5-yl cyanides were effectively synthesized in high yields (94-98%) within short reaction times (15 min). All synthesized compounds were well characterized by IR, ¹H and ¹³C NMR spectroscopy, and also by elemental analyses.

Conclusion: In conclusion, a simple, efficient, and green synthesis of 2,4-diamino-6-arylpyrimidine- 5-yl cyanides was developed using NiCr₂O₄ NPs as a green nanocatalyst, and under ultrasound radiation as a green tool. The mild reaction conditions, avoiding the use of toxic solvents or reagents, high atom economy, high yields, and simple workup are the attractive features of this new protocol.

背景：绿色化学研究领域的主要因素之一是使用超声波作为一种多功能合成工具来驱动化学反应。此外，纳米结构的金属盐在化学反应中作为低成本、高效、多相和绿色的催化剂占有重要地位。嘧啶也具有重要意义，因为它是各种天然和非天然物质的核心结构，其中许多表现出多种生物活性和医学应用。

目的：本研究的目的是探索镍 (II) 铬铁矿纳米粒子 (NiCr ₂ O ₄ NPs) 作为绿色可回收催化剂在合成 2,4-二氨基-6-芳基嘧啶-5-基氰化物中的作用。在超声波辐射下。

方法：以NiCr ₂ O ₄ NPs为有效的多相催化剂，在室温条件下，在超声辐射下进行硝酸胍、芳香醛和丙二腈的直接环缩合反应，制备2,4-二氨基-6-芳基-嘧啶-5高产率的-基氰化物。根据简单的水热路线成功制备了所描述的催化剂，并通过 X 射线衍射 (XRD) 技术、色散能 X 射线 (EDS) 分析、扫描电子显微镜 (SEM) 和动态光散射 (DLS) 进行了充分表征.

结果：在很短的反应时间（15 分钟）内，以高产率 (94-98%) 有效合成了许多 2,4-二氨基-6-芳基-嘧啶-5-基氰化物。所有合成的化合物都通过 IR、¹ H 和¹³ C NMR 光谱以及元素分析进行了很好的表征。

结论：总之，使用 NiCr ₂ O ₄ NPs 作为绿色纳米催化剂，并在超声辐射下作为绿色工具，开发了一种简单、高效、绿色的 2,4-二氨基-6-芳基嘧啶-5-基氰化物合成方法。温和的反应条件、避免使用有毒溶剂或试剂、高原子经济性、高产率和简单的后处理是这个新协议的吸引人的特点。