chemengineering Review Recent Advances on Quinazoline Derivatives: A Potential Bioactive Scaffold in Medicinal Chemistry Ram Karan 1 , Pooja Agarwal 1, * ,† , Mukty Sinha 2 and Neelima Mahato 3, * ,†   Citation: Karan, R.; Agarwal, P.; Sinha, M.; Mahato, N. Recent Advances on Quinazoline Derivatives: A Potential Bioactive Scaffold in Medicinal Chemistry. ChemEngineering 2021, 5, 73. https://doi.org/10.3390/ chemengineering5040073 Academic Editors: Alírio E. Rodrigues, Brian Trewyn, José P. Coelho and Andrew S. Paluch Received: 29 June 2021 Accepted: 27 September 2021 Published: 26 October 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Division of Chemistry, School of Basic and Applied Sciences, Galgotias University, Yamuna Expressway, Greater Noida 203201, India; ramkaran.ra@gmail.com 2 Department of Medical Devices, National Institute of Pharmaceutical Education and Research, Ahmedabad, Palej, Gandhinagar 382355, India; muktys@gmail.com 3 School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Korea * Correspondence: pooja.agarwal@galgotiasuniversity.edu.in (P.A.); neelapchem@gmail.com(N.M.); Tel.: +91-9899656455 (P.A.); +82-010-2798-8476 (N.M.) † Contributed equally as first author. Abstract: This paper intended to explore and discover recent therapeutic agents in the area of medicinal chemistry for the treatment of various diseases. Heterocyclic compounds represent an important group of biologically active compounds. In the last few years, heterocyclic compounds having quinazoline moiety have drawn immense attention owing to their significant biological activities. A diverse range of molecules having quinazoline moiety are reported to show a broad range of medicinal activities like antifungal, antiviral, antidiabetic, anticancer, anti-inflammatory, antibacterial, antioxidant and other activities. This study accelerates the designing process to generate a greater number of biologically active candidates. Keywords: quinazoline; antifungal; anticancer; anti-inflammatory; antibacterial; antioxidant 1. Introduction Heterocyclic rings containing nitrogen and sulfur are of much intention as they are therapeutically and pharmacologically more active. These compounds are the building blocks of many pharmaceutical products. Among all heterocyclic moieties, quinazoline has been taken for this review, as quinazoline has a very broad spectrum of pharmacological ac- tivities with minimum side effects [1]. Quinazoline is a well known heterocyclic compound having the chemical formula C 8 H 6 N 2 . Quinazoline is a light yellow crystalline solid and is also known as 1,3-diazanaphthalene, which comprises one benzene and one pyrimidine ring. Synthesis of quinazoline was first reported through decarboxylation of 2-carboxy derivative by August Bischler and Lang in 1895 [2]. Anthranilic acid on treatment with amide resulted in 4-oxo-3,4-dihydroquinazolies by Niementowski synthesis [3]. Other iso- mers of quinazoline are quinoaxoline, cinnoline and phthalizine [4]. Quinazolines are also the building blocks of more than 200 natural alkaloids isolated from plants, microorganisms and animals [5,6]. Vasicine (±) (peganine) was the first known quinazoline alkaloid which was isolated from Adhatoda vasica in 1888. It is highly effective against bronchodilator activity [7]. Quinazolinone is one of the derivatives of quinazoline which is active like quina- zoline [8]. Based on the substitution pattern, quinazolinones are further divided into subcategories such as 2-quinazolinone (a) and 4-quinazolinone (b) as shown in Figure 1 [9]. Thus, quinazoline is a structure of great interest in the area of pharmaceutical chem- istry, featuring in various drugs, clinical candidates and bioactive molecules. The focus of this review is on potential biological activity of quinazoline derivatives. This review article will be advantageous in providing information regarding the latest developments on quinazoline analogs having completely different pharmacological activities like antitu- mor, antimicrobial, antimalarial, antiviral and antidiabetic, etc. This review will also be ChemEngineering 2021, 5, 73. https://doi.org/10.3390/chemengineering5040073 https://www.mdpi.com/journal/chemengineering