Research Article Metal-free Catalyzed One-Pot Multicomponent Synthesis of (E)-3-(2-((5-(Benzylideneamino)-1,3,4-thiadiazol-2-yl)thio) Acetyl)-2H-chromen-2-one Derivatives and Their Biological Evaluation Shivanand Merugu, 1 Vijaya Kumar Ponnamaneni, 2 Ravi Varala, 3 Syed Farooq Adil , 4 Mujeeb Khan, 4 Mohammed Rafiq H. Siddiqui , 4 and Ravikumar Vemula 1 1 Department of Chemistry, Kamala Institute of Technology and Science, Huzurabad, Karimnagar 505 468, Telangana, India 2 Synocule Research Labs Private Limited, Plot No. 16, CFC Area, IDA Nacharam, Hyderabad 500 076, Telangana, India 3 Scrips Pharma, Mallapur, Hyderabad 500076, Telangana, India 4 Department of Chemistry, King Saud University, Riyadh 11451, Saudi Arabia Correspondence should be addressed to Syed Farooq Adil; sfadil@ksu.edu.sa and Ravikumar Vemula; vemularavi97@gmail.com Received 1 December 2019; Accepted 4 February 2020; Published 10 April 2020 Academic Editor: Andrea Penoni Copyright © 2020 Shivanand Merugu et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A series of (E)-3-(2-((5-(benzylideneamino)-1,3,4-thiadiazol-2-yl)thio) acetyl)-2H-chromen-2-one and its derivatives (4a-h) have been obtained using a one-pot multicomponent reaction with good yields. e compounds have been synthesized from 3-(2- bromoacetyl)chromen-2-ones ( 1), 5-amino-1,3,4-thiadiazole-2-thiol (2), and substituted benzaldehydes (3) in anhydrous ethanol and conc. H 2 SO 4 . Subsequently, all the synthesized compounds have been screened for their antimicrobial activity and char- acterized by analytical and spectral data. 1. Introduction Over the several decades, the interest of the scientific community in the heterocyclic compounds and their various derivatives has been persistent due to their broad applica- tions in pharmaceutical and chemical industries [1]. Among various heterocyclic compounds such as pyrazole, tetrahy- droquinoline, and benzotriazole, thiadiazole has gained prominent importance which consists of an important five- membered heterocyclic system containing two nitrogen atoms and a sulfur atom [2]. Particularly, among various thiadiazole, the 1,3,4,-thiadiazole has been studied more than any other counterpart, due to its biologically signifi- cance [3]. e 1,3,4-thiadiazole and most of their derivatives are important heterocyclic entities in pharmaceutical as well as in medicinal chemistry, due to their diverse biological activities as well as inhibition properties against a variety of specific enzymes [4], several of which are known to possess excellent antibacterial [5], antimicrobial [4, 6], anti-in- flammatory [7], anticonvulsant [8], antidepressant and anxiolytic [9], anti-tuberculosis [10], anticancer [11], and CNS depressant activities [12]. In this regard, various coumarin (benzopyran-2-one) derivatives have particularly shown remarkable biological activities due to their privileged structure which facilitates high affinity and specificity to different molecular targets [13]. Besides, the presence of planar aromatic ring fused with lactone functionality, availability of highly interactive functional groups which enhances the interactions with foreign moieties including proteins makes this heterocycle a unique pharmacophore in the field of medicinal chemistry. In view of this importance, the present study focused on a facile one-pot multicomponent reaction of Schiff base containing heterocyclics. A multicomponent reaction Hindawi Journal of Chemistry Volume 2020, Article ID 4869279, 7 pages https://doi.org/10.1155/2020/4869279