Nanochem Res 4(2): 154-162, Summer and Autumn 2019 RESEARCH PAPER Co 3 O 4 /NiO@GQDs@SO 3 H nanocomposite as an effecve catalyst for the synthesis of pyranopyridines Hossein Shahbazi-Alavi 1* , Ali Kareem Abbas 2 ,Javad Safaei-Ghomi 3 1 Young Researchers and Elite Club, Kashan Branch, Islamic Azad University, Kashan, Iran, Iran 2 College of applied medical sciences, University of Kerbala, Iraq 3 Department of Organic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, Iran * Corresponding Author Email: hossien_shahbazi@yahoo.com Co 3 O 4 /NiO@GQDs@SO 3 H nanocatalyst has been used as an effecve catalyst for the preparaon of benzopyranopyridines through a four- component reacon of salicylaldehydes, thiols and 2 equiv of malononitrile under reflux condion in ethanol. The catalyst has been characterized by FT-IR, XRD, SEM, EDS, BET, XPS, TGA and VSM. Atom economy, reusable catalyst, low catalyst loading and high yields of products are some of the notable features of this method. The best results were gained in EtOH and we found the convincing results for the reacon in the presence of Co 3 O 4 /NiO@GQDs@SO 3 H nanocomposite (4 mg) under reflux condions. Also, a series of salicylaldehydes and different thiols were studied under opmum condions. ARTICLE INFO Arcle History: Received 26 June 2019 Accepted 17 September 2019 Published 15 October 2019 Keywords: Nanocomposite One-pot Heterogeneous catalysts Pyranopyridines Nanoanalysis ABSTRACT is 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/. How to cite this article Shahbazi-Alavi H, Kareem Abbas A, Safaei-Ghomi J. Co 3 O 4 /NiO@GQDs@SO 3 H nanocomposite as an effective catalyst for the synthesis of pyranopyridines. Nanochem Res, 2019; 4(2):154-162. DOI: 10.22036/ncr.2019.02.007 INTRODUCTION Pyranopyridines show biological activities including antipsychotic [1], anti-inflammatory [2], anti-asthma [3], antiallergic [4] and antibacterial [5]. ese activities make benzopyranopyridines attractive targets in organic synthesis. A number of procedures have been developed for the preparation of pyranopyridines using K 2 CO 3 [6], Et 3 N [7,8] and NaOH [9]. Despite the use of these ways, there remains a need for further new methods for the synthesis of benzopyranopyridines. GQDs have achieved intense attention owing to the remarkable features containing biological [10], biomedical [11], drug delivery [12], photocatalysts [13], surfactants [14], electrochemical biosensing [15], electrocatalytic [16], Li-ion battery [17], optical properties and photovoltaic applications [18], photoluminescence [19-20], bioimaging properties [21], and catalytic activity [22]. Potential applications of N-graphene quantum dots were lately reviewed on the basis of theoretical and experimental studies [23-26]. Preparation of the highly efficient nanocomposite catalysts for the synthesis of organic compounds is still an attractive challenge. To attain larger surface area, nanocatalysts are functionalized by active groups [27-29]. e decoration of the nanoparticles with GQDs prevents the aggregation of fine particles and thus increases the efficient surface area and the number of reactive sites for an effective catalytic reaction. e -SO 3 H and -COOH groups can be used as acid catalysts for many reactions [22-30]. Herein, we reported the use of Co 3 O 4 /NiO@GQDs@SO 3 H nanocomposite as an efficient catalyst for the preparation of benzopyranopyridines through a four-component reaction of salicylaldehydes, thiols and 2 equiv of malononitrile under reflux condition in ethanol (Scheme 1). EXPERIMENT Materials and characterization e powder X-ray diffraction was taken on a Philips diffractometer of X’pert Company with monochromatized Cu Kα radiation (λ = 1.5406