Abstract

In the present work, we report an proficient, elegant, and rapid one-pot synthesis of variety of 3,4-dihydropyrimidine-2(1H)-one/thione derivatives from β-dicarbonyl compounds, urea/thiourea, and various aromatic aldehydes using nano-La₂O₃ catalyst under ultrasonic irradiation. This novel synthetic strategy benefits with excellent yields, short reaction time, benign reaction conditions, clean transformation, and purification of products by non-chromatographic strategies. In addition, the synthesized nano-material was also explored as an effective gas sensor for NO₂, LPG, methyl alcohol, and ammonia. The gas-sensing properties such as selectivity and sensitivity of selected gases along with response and recovery for nano-La₂O₃ sensor are reported in this paper. In this way, conferring nano-La₂O₃ is a multifunctional catalyst not only for organic synthesis but also for gas sensing. The synthesized La₂O₃ nano-material was characterized by Fourier transform IR, powder X-ray diffraction, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive spectroscopy, and Brunauer–Emmett–Teller isotherm. The formation of Biginelli adducts was confirmed by Fourier transform IR, ¹HNMR, ¹³CNMR, DEPT-135 (distortionless enhancement by polarization transfer spectra), and mass spectral techniques.

Graphical abstract

中文翻译：

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纳米La 2 O 3作为二氢嘧啶酮/硫酮合成和气敏有效催化剂的催化性能的探索

摘要

在本工作中，我们报告了一种高效，优雅，快速的一锅合成方法，该方法可从β-二羰基化合物，脲/硫脲和各种芳香族化合物中合成各种3,4-二氢嘧啶-2（1 H）-一/硫酮衍生物纳米La ₂ O ₃催化剂在超声辐射下制备醛类。这种新颖的合成策略具有出色的收率，较短的反应时间，良好的反应条件，干净的转化以及通过非色谱策略纯化产物的优势。另外，还研究了合成的纳米材料作为用于NO ₂，LPG，甲醇和氨的有效气体传感器。气体感应特性，例如选定气体的选择性和敏感性，以及对纳米La的响应和回收率本文报道了₂ O ₃传感器。以此方式，赋予纳米La ₂ O ₃不仅是用于有机合成而且用于气体感测的多功能催化剂。合成的La ₂ O ₃纳米材料的特征在于傅立叶变换红外光谱，粉末X射线衍射，场发射扫描电子显微镜，高分辨率透射电子显微镜，能量色散光谱和Brunauer-Emmett-Teller等温线。通过傅立叶变换红外光谱，¹ HNMR，¹³ CNMR，DEPT-135（通过极化转移光谱进行的无畸变增强）和质谱技术确认了Biginelli加合物的形成。

图形概要