Department of Chemistry, Science and Research Branch, Islamic Azad University, P.O. Box 14515-775, Tehran, Iran.
Department of Chemistry, East Tehran Branch, Islamic Azad University, P.O. Box 18735-138, Tehran, Iran.
Comb Chem High Throughput Screen. 2021;24(1):139-147. doi: 10.2174/1386207323666200712145041.
In the last decades, it has extensively been verified that nanostructured transition metal oxides emerge as inexpensive, available and extremely efficient heterogeneous catalysts in chemical transformations. The high electrical conductivity, high carrier concentration, and improved reactivity in cadmium oxide nanoparticles (CdO NPs) make it as a potential candidate for applications in the fields of nanocatalysis. [1]Benzopyran and pyridopyrimidine derivatives compose major classes of heterocyclic compounds, which have a wide spectrum of biological activities.
In the present work, we report a facile and highly effective synthesis of 8- aryl-8H-[1,3]dioxolo[4,5-g][1]benzopyran-6-carboxylic acids and 1,3-dimethyl-2,4-dioxo-5- phenyl-1,2,3,4,5,8-hexahydropyrido[2,3-d]pyrimidine-7-carboxylic acids via CdO NPs catalyzed cyclo condensation reaction of 4-substituted phenylmethylidenepyruvic acids with 3,4- methylenedioxyphenol or 6-amino-1,3-dimethyluracil, which was accomplished under ethanoldrop grinding at room temperature. The described catalyst was prepared successfully by a simple precipitation method and characterized by the Fourier transformed infrared absorption (FT-IR) spectroscopy, X-Ray diffraction (XRD) analytical technique, and scanning electron microscopy (SEM).
A number of [1,3]dioxolo[g][1]benzopyran-6-carboxylic acids and pyrido[d]pyrimidine- 7-carboxylic acids were effectively synthesized in high yields (96-98%) within short reaction times (10-15 min). All synthesized compounds were well-characterized by IR, 1H and 13C NMR spectroscopy, and also by elemental analyses.
In summary, we have developed a very simple and impressive procedure for the synthesis of 8-aryl-8H-[1,3]dioxolo[4,5-g][1]benzopyran-6-carboxylic acids and 1,3-dimethyl- 2,4-dioxo-5-phenyl-1,2,3,4,5,8-hexahydropyrido[2,3-d]pyrimidine-7-carboxylic acids as biologically interesting structures in the presence of CdO NPs as an efficient recyclable heterogeneous catalyst. The remarkable advantages for the offered protocol compared with traditional methods are short reaction time, good yields of the products, and the ease of operation with simple work-up procedure.
在过去的几十年中，已经广泛证明，纳米结构的过渡金属氧化物作为化学转化中的廉价、易得且极其高效的多相催化剂出现。氧化镉纳米粒子（CdO NPs）具有高导电性、高载流子浓度和增强的反应性，使其成为纳米催化领域应用的潜在候选材料。[1]苯并吡喃和吡啶并嘧啶衍生物是杂环化合物的主要类别，具有广泛的生物活性。
在本工作中，我们报告了一种简便高效的合成 8-芳基-8H-[1,3]二氧杂环戊烷[4,5-g][1]苯并吡喃-6-羧酸和 1,3-二甲基-2,4-二氧代-5-苯基-1,2,3,4,5,8-六氢吡啶并[2,3-d]嘧啶-7-羧酸的方法，该方法通过 CdO NPs 催化 4-取代苯亚甲基丙酮酸与 3,4-亚甲二氧基苯酚或 6-氨基-1,3-二甲基尿嘧啶的环缩合反应来实现，该反应在室温下通过乙醇滴磨完成。所述催化剂通过简单的沉淀法成功制备，并通过傅里叶变换红外吸收（FT-IR）光谱、X 射线衍射（XRD）分析技术和扫描电子显微镜（SEM）进行了表征。
在短反应时间（10-15 分钟）内，以高产率（96-98%）有效地合成了多种[1,3]二氧杂环戊烷[g][1]苯并吡喃-6-羧酸和吡啶并[d]嘧啶-7-羧酸。所有合成的化合物均通过 IR、1H 和 13C NMR 光谱以及元素分析进行了良好的表征。
总之，我们开发了一种非常简单且引人注目的方法，用于在 CdO NPs 作为高效可回收多相催化剂的存在下合成具有生物意义的 8-芳基-8H-[1,3]二氧杂环戊烷[4,5-g][1]苯并吡喃-6-羧酸和 1,3-二甲基-2,4-二氧代-5-苯基-1,2,3,4,5,8-六氢吡啶并[2,3-d]嘧啶-7-羧酸。与传统方法相比，该方法的显著优点是反应时间短、产物收率高、操作简单、后处理简单。
