Tis work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Nanochem Res 7(1): 28-35, Winter and Spring 2022 RESEARCH PAPER Sonosynthesis of Pyrimidines as Antmicrobial Agents Using Nano- Fe 3 O 4 –L-cysteine Hossein Shahbazi-Alavi 1,* , Javad Safaei-Ghomi 2 1 Young Researchers and Elite Club, Kashan Branch, Islamic Azad University, Kashan, Iran 2 Department of Organic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, Iran * Corresponding Author Email: hossien_shahbazi@yahoo.com hossien_shahbazi@yahoo.com Nano-Fe 3 O 4 –L-cysteine as a superior catalyst was applied for the synthesis of pyrimidine-trions by three-component reactons of N,N-dimethylbarbituric acid, benzaldehydes and para-methyl aniline or para-methoxy aniline under ultrasonic irradiaton in ethanol. The catalyst was characterized by SEM, FT-IR, XRD, TGA, EDS and VSM. In additon, screening diverse catalysts containing Et 3 N, p-TSA, nano NiO, nano Fe 3 O 4 , cysteine and nano-Fe 3 O 4 –L-cysteine revealed nano- Fe 3 O 4 –L-cysteine (4 mg) as the most efectve catalyst to perform this reacton under ultrasonic irradiaton in ethanol. Further, the compounds 4b (5-((2-amino- 5-methoxyphenyl)(4-(methylthio)phenyl)methyl)-1,3-dimethylpyrimidine- 2,4,6(1H,3H,5H)-trione), 4c (5-((2-amino-5-methoxyphenyl)(4-chlorophenyl) methyl)-1,3- dimethylpyrimidine 2,4,6(1H,3H,5H)-trione) and 4f (5-((2-amino- 5-methylphenyl)(2,4-dichlorophenyl)methyl)-1,3-dimethylpyrimidine-2,4,6 (1H,3H,5H)-trione) have moderate growth inhibitory efects on Gram positve bacteria (Staphylococcus aureus, Bacillus subtlis; and Staphylococcus epidermidis). The compound of 4b has moderate growth inhibitory efects on fungi. This technique provides several benefts including the use of ultrasonic irradiaton, great yields in concise tmes, retrievability the nanocatalyst and low nanocatalyst loading. The present catalytc method is extensible to a wide range of substrates for the preparaton of a variety-oriented library of pyrimidines. ARTICLE INFO Artcle History: Received 17 February 2022 Accepted 14 April 2022 Published 1 May 2022 Keywords: Nanocatalyst Pyrimidines Ultrasonic Antmicrobial Nano-Fe 3 O 4 ABSTRACT How to cite this article Shahbazi-Alavi H., Safaei-Ghomi J. Sonosynthesis of Pyrimidines as Antimicrobial Agents Using Nano-Fe 3 O 4 –L-cysteine. Nanochem Res, 2022; 7(1):28-35. DOI: 10.22036/ncr.2022.01.005 INTRODUCTION Pyrimidines exhibit anti-cancer [1], glucosidase inhibitor [2], antioxidant [3], anti-microbial [4] and anaesthetic activities [5]. However, fnding an efective detection method for the synthesis of pyrimidones is a drastic challenge. Te preparation of pyrimidines has been studied using a number of catalysts including indium (III) chloride [6], tungstophosphoric acid [7], potassium carbonate [8], tosylic acid [9] and 1-N-butyl-3- methylimidazolium hexafuorophosphate [10]. Despite using these catalysts, the need for further novel ways of synthesizing pyrimidines continues to exist. Nano-magnetic materials have been applied as a robust nanocatalyst with a very notable feature of straight separation by external magnet [11-14]. Nano-magnetic materials have been utilized as a useful series of heterogeneous catalysts due to their diverse applications in catalysis and synthesis [15-20]. Te surface of nano-magnetics can be functionalized using suitable surface modifcations for creating additional types of desired functionalities [21-22]. Herein, we report the use of Fe 3 O 4 –L-cysteine nanoparticles as an efective catalyst for the preparation of pyrimidine- trions by three-component reactions of N,N- dimethylbarbituric acid, benzaldehydes and para- methyl aniline or para-methoxy aniline under ultrasonic irradiation in ethanol (Scheme 1).