Synthesis, Antibacterial, Antioxidant Activity and QSAR Studies of Novel 2-Arylidenehydrazinyl-4-arylthiazole Analogues

Abstract

A novel series of 2-arylidenehydrazinyl-4-arylthiazole analogues (3a-p) was designed and synthesized in excellent yields using a rapid, simple, efficient methodology. Sixteen novel compounds were screened for in vitro antimicrobial activities against eleven bacteria, namely, Staphylococcus aureus, Listeria monocytogenes, Enterococcus faecalis, Bacillus subtilis, Klebsiella pneumonia, Citrobacter freundii, Cronobacter sakazakii, Salmonella enteritidis, Escherichia coli, Yersinia pestis, and Pseudomonas aeruginosa. All 16 compounds showed significant anti-bacterial activities against both Gram-positive and Gram-negative bacteria. In particular, compound 3g showed potent inhibition of E. coli and K. pneumonia, compound 3i inhibited E. faecalis, compound 3n S. tythi and E. faecalis, and compound 3c E. coli and C. sakazakii. In fact, our results indicate that most of the compounds synthesized exhibit strong antibacterial activity. The qualitative structureantibacterial activity relationships (QSAR) were studied using the physicochemical and quantum-chemical parameters of the ab initio Hartree-Fock model at the RHF/6-31G level of theory. A good qualitative correlation between predicted physicochemical parameters (log P and polar surface area (PSA)) and antibacterial activity has been found. The synthesized compounds were also evaluated for antioxidant activity. Compounds 3j, 3a and 3i exhibited the greatest antioxidant activity, with IC 50 values of 0.66, 0.81, and 1.08 µM, respectively, which were comparable to that of ascorbic acid (IC 50 0.87 µM). The promising antibacterial and antioxidant activities of some of these synthesized 2-arylidenehydrazinyl-4-arylthiazole derivatives, together with the results of quantum-chemical studies, could be helpful for the development of drugs to combat diseases caused by microorganisms and oxidative stress.

Structural Properties and Catalytic Activity of Binary Poly (vinyl alcohol)/Al2O3 Nanocomposite Film for Synthesis of Thiazoles

“…PVA (molecular weight = 22,000 g/mol, density = 1.19 g/cm 3 ), Al 2 O 3 nanoparticles (Merck 642991; 30-60 nm particle size (TEM); 20 wt% in water), and ethylenediamine (ED) were purchased by Sigma Aldrich. Thiosemicarbazones 1a-g were prepared as reported in literature [23][24][25][26][27]. Melting points of authenticated samples 3a-j were measured on an electrothermal Gallenkamp capillary apparatus (Leicester, UK).…”

Novel Fluorescent Schiff Base Derivatives of 4‐Aminoantipyrine with Large Stokes Shifts and Dual Emission Properties: Crystal Structure, Molecular Interactions, Molecular Surfaces, Conformational and DFT Analyses

“…Molecular electrostatic potential (MEP) and molecular lipophilic potential (MLP) maps and polar surface areas (PSA) are important predictors of chemical and biological behavior and reactivity and map potentials created in 3D space by the electron density distributions and atomic properties of molecules. MEP maps help identify sites of electrophilic and nucleophilic attack and locate hydrogen‐bonding interactions, whereas MLP and PSA maps with MEP analysis provide useful information for predicting drug–receptor and enzyme–substrate interactions.…”

“…A literature survey revealed that Schiff‐base derivatives have excellent coloring, thermal, and optical properties and are used as dyes, for optical data storage, for photo‐switching, in nonlinear optics, as photochromic materials, and for chemical analysis. Schiff bases also exhibit wide‐ranging biological activities; e.g ., they are used as antimicrobials, antifungals, antioxidants, antitumor agents, and herbicides; to inhibit DNA, RNA, and protein synthesis; and for nitrogen fixation, and have carcinogenesis properties. Schiff bases are widely used as ligands to form coordination bonds with transition‐ and inner‐transition‐metal ions with wide biological and chemical applications; e.g ., they are used as antimicrobials, cytotoxic agents, in thermal studies, as electrochemical sensors, and as catalysts …”

Crystal structure and Hirshfeld surface analysis of N-(5-iodo-4-phenylthiazol-2-yl)acetamide

“…The 1,3-thiazole ring is a structural motif frequently found in the pharmaceutical field in antibacterial (Alam et al, 2014), antifungal (Yu et al, 2007) and antiviral (Liu et al, 2011) agents among others. In the chemotherapy of protozoal diseases, 5-bromo-2-aminothiazole derivatives have been investigated as privileged structures in biological tests against intestinal parasites such as Giardia (Mocelo-Castell et al, 2015).…”