ORIGINAL PAPER Synthesis of New 2-Amino-3-(2-Oxothiazol-Methyl) -Substituted-1,4-Naphthoquinone Derivatives Based on Silica Nanoparticles as a Reusable Heterogeneous Catalyst Hassan Vasheghani Farahani 1 & Mohammad Bayat 1 & Shima Nasri 1 Received: 6 November 2018 /Accepted: 31 January 2019 # Springer Nature B.V. 2019 Abstract A novel series of 2-amino-3-(2-oxothiazol-methyl)-substituted-1,4-naphthoquinone compounds were designed and prepared, by the three-component one-pot reaction of 2-aminothiazole, 2-hydroxy-1-4-naphthoquinone and aromatic aldehydes using of nano-SiO 2 (20% mol) as an efficient Lewis acid and heterogeneous nano-catalyst in acetonitrile at room temperature in the period of time 2–5 h. Silica-based materials used for developing an environmental friendly methodology for the preparation of potential biologically active molecular scaffolds. The direction of product formation and the structure of all the synthesized compounds were identified by spectroscopic methods. The remarkable superiorities of this procedure include good yields (70– 89%), use of an inexpensive and commercially available catalyst, regioselectivity and simple work-up. Keywords 2-Aminothiazole . 2-amino-oxothiazol-methyl-naphthoquinone . Silica-based nanoparticle . Nano-SiO 2 . Heterogeneous catalyst 1 Introduction To date, various chemotherapy drugs have been developed to treat various cancers that efficiently kill cancer cells, but there are many side effects due to chemotherapy [1]. On the other hand, because of the resistance of bacterial and fungal patho- gens [2], and emerging newer infectious diseases [3] have created a widespread and growing demand for new efficiently therapeutic potential compounds with less toxicity to treat cancer and for antibacterial and antifungal compounds. Quinone, a structurally important moiety is widely found in many natural products and is the main pharmacophore of var- ious clinically significant drugs [4]. Among the quinone com- pounds, 2-amino-substituted-1,4-naphthoquinone compounds are used as herbicides [5] and they also exhibited attractive redox switching aspects [6] and various attractive biological properties such as antitumor, [7] antimalarial, [8] antibacterial, [9] antitubercular, [10] and fungicide [11] with low toxicity compared with alkyl naphthoquinones and 2-hydroxy-1,4- naphthoquinone [12]. Generally, 2-amino-substituted-1,4- naphthoquinone compounds were formed by three different synthetic procedures. For example, the reaction of amines with 1,4-naphthoquinone using molecular iodine under ultra- sonic irradiation condition, the nucleophilic substitution of 2- halo-substituted benzoquinone, or the 1,4-addition of the pri- mary amines to 1,4-naphthoquinone using Lewis acid [13–15]. Despite the simplicity of the synthesis methods of such compounds by the reaction of amine with various qui- nones, these compounds have a wide range of applications, especially in the field of synthesis of various polymers or electro/photoactive supramolecular assemblies [16]. Meanwhile, there are several factors that affect the biologi- cal evaluation of the quinone structures [2], such as a change in the chemical structure and presentation of other heterocyclic rings (e.g., thiazole moiety) to the main quinone moiety [17]. Thiazoles are useful structural units in the field of medicinal chemistry and have been very well known for their therapeutic applications and biological activities including antimicrobial, antiviral, antimalarial, anticancer, hypertension, inflammation, schizophrenia, HIV infections and so on [18–21]. A family of 2-amino-substituted-1,4-naphthoquinone compounds connect- ed to thiazole via a methyl chain may have potential antitumor and antifungal activity, but the compounds with this structure have not yet been introduced in the literatures. * Mohammad Bayat bayat_mo@yahoo.com; m.bayat@sci.ikiu.ac.ir 1 Department of Chemistry, Faculty of Science, Imam Khomeini International University, Qazvin, Iran Silicon https://doi.org/10.1007/s12633-019-0098-z