Asparagine functionalized Al 2 O 3 nanoparticle as a superior heterogeneous organocatalyst in the synthesis of 2-aminothiazoles Zohre Zarnegar a , Zahra Shokrani b , Javad Safari b, * a Research Affiliate, Department of Chemistry, University of Payame Noor, P.O. BOX 19395-4697, Tehran, Iran b Laboratory of Organic Compound Research, Department of Organic Chemistry, College of Chemistry and Biochemistry, University of Kashan, P.O. Box 87317-51167, Kashan, Islamic Republic of Iran article info Article history: Received 19 November 2018 Received in revised form 18 February 2019 Accepted 20 February 2019 Available online 26 February 2019 Keywords: Thiazoles Al 2 O 3 nanoparticles Asparagine One-pot synthesis Organocatalyst abstract Asparagine functionalized aluminum oxide nanoparticles (Asp-Al 2 O 3 ) have been prepared by a two-step procedure involving the grafting of Al 2 O 3 with 3-chloropropyltrimethoxysilane (CPTMS) and subsequent organofunctionalization using asparagine amino acid. It is shown that Asp-Al 2 O 3 exhibits as an active nanocatalyst for the preparation of 2-aminothiazoles is achieved by one-pot reaction of methylcarbonyls, thiourea and iodine. The structure of Asp-Al 2 O 3 was characterized by fourier transform infrared radiation (FT-TR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopic (SEM), and energy-dispersive analysis of X-ray (EDAX) analyses. Advantages of this modified method- ology include higher purity and excellent yield of products, greener and cleaner conditions, easy isolation of products and convenient manipulation. Moreover, immobilization of organocatalysts on the Al 2 O 3 surface are stable under the catalytic reaction conditions resulting their efficient reuse. © 2019 Elsevier B.V. All rights reserved. 1. Introduction Aluminum oxide (Al 2 O 3 ) nanoparticles are utilized for various applications in industry and chemistry. Such as catalysis in petro- leum refining, ceramic composites, optoelectronics, electronics, hydrogenation, automotive emission control, metallurgy, re- fractories, and wear protection [1e6]. Notably, g-Al 2 O 3 nano- particles as a catalytic support and nanocatalyst has been explored for diverse organic reactions [7e10]. In practical applications, the use of modified nano g-Al 2 O 3 with organic and inorganic materials led to the development of their superior catalytic activities due to some of advantages for example large surface area, pore-size dis- tribution, pore volume, facile surface modification, and acid/base characteristics [9, 10]. To the best of our knowledge, there is no amino acid functionalized Al 2 O 3 nanoparticles as catalytic systems for the organic conversions. Nowadays, the use of organocatalysts have attracted great attention in modern chemistry. They can catalyze chemical pro- cesses as Brønsted acids, Brønsted bases, Lewis acids, and Lewis bases. Organic based catalysts are often based on nontoxic organic compounds originating from biological materials like amino acids [11 , 12]. Recently, amino acids are widely used in organic trans- formations such as proline in Michael reaction [13] and Robinson annulation [14], various amino acids in the Biginelli dihy- dropyimidone synthesis [15], valine for synthesis of substituted pyrrolidines [16], tryptophan for the Mannich reaction and aldol reaction [17], phenylalanine in synthesis of imidazolines [18], and etc [19]. However, in the homogeneous catalytic conditions have limited their application because of their difficult separation from the reaction environment. In recent years, heterogeneous organo- catalysts have caused the extensive attention due to their recyclable and environmental friendly property. Therefore, in this research, we report the efficient activity of asparagine catalyst supported on aluminum oxide nanoparticles (Asp-Al 2 O 3 ) as an effective catalyst to produce 2-aminothiazole scaffolds. Thiazoles are important branches of the azole heterocycles that contain both nitrogen and sulfur in their aromatic rings. Thiazole and their substituted analogues as biologically active compounds have been extensively used as sulfur drugs [20e23]. The first report for the synthesis of thiazole is proposed by Hantzsch and Weber in 1887. The Hantzsch thiazole synthesis is a reaction between hal- oketones and thioamides or thiourea [24]. Among the important thiazoles, 2-aminothiazole and their derivatives have attracted increasing attention from synthetic chemists due to their potential biological properties and pharmacological importance such as * Corresponding author. , E-mail addresses: safari_jav@yahoo.com, safari@kashanu.ac.ir (J. Safari). Contents lists available at ScienceDirect Journal of Molecular Structure journal homepage: http://www.elsevier.com/locate/molstruc https://doi.org/10.1016/j.molstruc.2019.02.080 0022-2860/© 2019 Elsevier B.V. All rights reserved. Journal of Molecular Structure 1185 (2019) 143e152