Synthesis, In Silico Prediction and In Vitro Evaluation of Antimicrobial Activity, DFT Calculation and Theoretical Investigation of Novel Xanthines and Uracil Containing Imidazolone Derivatives

Novel xanthine and imidazolone derivatives were synthesized based on oxazolone derivatives 2a-c as a key intermediate. The corresponding xanthine 3-5 and imidazolone derivatives 6-13 were obtained via reaction of oxazolone derivative 2a-c with 5,6-diaminouracils 1a-e under various conditions. Xanthine compounds 3-5 were obtained by cyclocondensation of 5,6-diaminouracils 1a-c with different oxazolones in glacial acetic acid. Moreover, 5,6-diaminouracils 1a-e were reacted with oxazolones 2a-c in presence of drops of acetic acid under fused condition yielding the imidazolone derivatives 6-13. Furthermore, Schiff base of compounds 14-16 were obtained by condensing 5,6-diaminouracils 1a,b,e with 4-dimethylaminobenzaldehyde in acetic acid. The structural identity of the resulting compounds was resolved by IR, 1H-, 13C-NMR and Mass spectral analyses. The novel synthesized compounds were screened for their antifungal and antibacterial activities. Compounds 3, 6, 13 and 16 displayed the highest activity against Escherichia coli as revealed from the IC50 values (1.8–1.9 µg/mL). The compound 16 displayed a significant antifungal activity against Candia albicans (0.82 µg/mL), Aspergillus flavus (1.2 µg/mL) comparing to authentic antibiotics. From the TEM microgram, the compounds 3, 12, 13 and 16 exhibited a strong deformation to the cellular entities, by interfering with the cell membrane components, causing cytosol leakage, cellular shrinkage and irregularity to the cell shape. In addition, docking study for the most promising antimicrobial tested compounds depicted high binding affinity against acyl carrier protein domain from a fungal type I polyketide synthase (ACP), and Baumannii penicillin- binding protein (PBP). Moreover, compound 12 showed high drug- likeness, and excellent pharmacokinetics, which needs to be in focus for further antimicrobial drug development. The most promising antimicrobial compounds underwent theoretical investigation using DFT calculation

Novel Enrofloxacin Schiff Base Metal Complexes: Synthesis, Spectroscopic Characterization, Computational Simulation and Antimicrobial Investigation against Some Food and Phyto-Pathogens

Condensation of the reaction between enrofloxacin and ethylenediamine in the existence of glacial acetic acid produced a new N,N-ethylene (bis 1-cyclopropyl-7-(4-ethylpiperazin-1-yl)-6-fluoro-1,4-dihydroquinoline-3-carboxylic acid Schiff base (H2Erx-en). H2Erx-en was used as a tetra-dentate ligand to produce novel complexes by interacting with metal ions iron(III), yttrium(III), zirconium(IV), and lanthanum(III). The synthetic H2Erx-en and its chelates had been detected with elemental analysis, spectroscopic methods, mass spectrometry, thermal studies, conductometric and magnetic measurements experiments. The calculated molar conductance of the complexes in 1 × 10−3 M DMF solution shows that iron(III), yttrium(III) and lanthanum(III) are 1:1 electrolytes, however the zirconium(IV) complex is non-electrolyte. The infrared spectra of H2Erx-en chelates indicated that the carboxylic group is deprotonated and H2Erx-en is associated with metals as a tetra-dentate through nitrogen and oxygen atoms. The disappearance of the carboxylic proton in all complexes corroborated information concerning H2Erx-en deprotonation and complexation with metal ions, according to 1H NMR data. Thermal analysis revealed the abundance of H2O particles in the chelates’ entrance and outlet spheres, indicating the disintegration pattern of H2Erx-en and their chelates. The Coats–Redfern and Horowitz–Metzeger approaches were utilized to calculate the thermodynamic items (Ea, ΔS *, ΔH *, and ΔG *) at n = 1 and n ≠ 1. The resulting data reveal better organized chelate building activation. Density functional theory (DFT) was created to properly grasp the optimal architecture of the molecules. The chelates are softer than H2Erx-en, with estimates varying between 95.23 eV to 400.00 eV, compared to 31.47 eV for H2Erx-en. The disc diffusion technique was utilized to assess H2Erx-en and their chelates in an antimicrobial assay against various food and phytopathogens. The zirconium(IV) chelate has the most potent antibacterial action and is particularly efficient against Salmonella typhi

Oxidative Degradation of Thermosets Based on Thioketal Cleavable Linkages in Aqueous Environment

Thermosets are rigid, infusible, and unmolded materials containing three-dimensional (3D) cross-linked structures. They are considered a fundamental pillar in the international economy, which are produced by 65 million tons annually. The responsive cross-linking moieties provide the thermosets characterized with outstanding physicochemical properties such as stiffness, degradability, and chemical and thermal resistance. We prepared degradable thermoset materials using thioketal (TK) cross-linkers, which underwent main-chain or side change degradation in the presence of hydrogen peroxide in water. TK cross-linkers at different concentrations (5, 10, and 20% wt %) were polymerized with 2-hydroxyethyl acrylate (HEA) or with 2-hydroxyethyl methacrylate (HEMA) and 1-vinyl-2-pyrrolidone (PD) to produce cross-linked poly(HEA) and poly(HEMA-PD) by free radical polymerization, respectively. The resultant polymer materials completely degraded in hydrogen peroxide/water (3–30%, vol). Using isophorone diisocyanate, we also produced degradable polyurethane based on TK-bearing diol. We prepared a 3D degradable thermoset using the Direct-Ink-Writing (DIW) 3D printing technology, which was charged by diethylene glycol diacrylate (15%, wt %) and a prepolymer (isophorone diisocyanate terminated by acrylate moieties) containing diol-thioketal linkage (15%, wt %). Finally, we found that TK-poly(HEA) underwent microbial degradation by Lactobacillus jensenii at 37 °C, which indicates a benign eco-friendly effect