Advanced synthetic and pharmacological aspects of 1,3-oxazoles and benzoxazoles

833-853Broad bio-spectrum of 1,3-oxazole and benzoxazole has created an attractive platform for synthetic chemists to introduce structural modification in its nucleus by straight forward access to new approaches. Owing to its fascinating features and interesting pharmacological activities, many researchers have proved that oxazole is an active agent in treating different diseases. Based on this fact, this article outlines intramolecular and two component intermolecular cyclization to oxazoles and benzoxazoles. The theme is well documented in this review article covering the era from 2007 till present. Moreover, bioactivity and mechanistic insights are provided with different synthetic approaches, encompassing various pathways

Conventional-Microwave Mediated Synthesis and In Vitro Antimicrobial Activity of Novel Carbazole-Efflux Pump Inhibitor Hybrid Antibacterials

Work presented herein is the first report of two dual-action hybrids synthesized by covalent linkage of carbazole based novel antibacterial compounds with efflux pump inhibitors, that is, indole acetic acid/gallic acid. In this paper, novel antibacterial compounds 2 and 3 were prepared first and then these were covalently linked with efflux pump inhibitors, that is, indole acetic acid/gallic acid leading to the successful formation of two dual-action hybrids 4 and 5. Prepared antibacterials and hybrids were evaluated for their bacteria cell killing capability against Escherichia coli, Staphylococcus aureus, Pasteurella multocida, and Bacillus subtilis. Both antibacterial compounds 2 and 3 were found effective against all tested bacterial strains at different concentrations. But when these compounds were linked with efflux pump inhibitors, they showed dramatic enhancement in their bacterial cell killing potential and minimum inhibitory concentration of all hybrids ranging from 7.250 μg/mL to 0.05 μg/mL. These prepared hybrid drugs will be promising and effective new agents in the category of dual-action antibiotics

Microwave-Assisted Synthesis of Tetrahydrocarbazole Linked 1,2-Diazoles in Aqueous-Brønsted Acid Catalytic System

A new series of tetrahydrocarbazole coupled 1,2-diazoles 4/5/6(a–o) in moderate to excellent yield was synthesized successfully via multicomponent reaction approach by adopting Michael type-addition of hydrazines on in situ generated α,β-unsaturated ketones via aldol type strategy under synthetic microwave radiations and conventional heating. Structural confirmations of all the prepared compounds were achieved by spectroscopic techniques. The best results were achieved when equal amounts of water-acetic acid were used in microwave conditions in 4 minutes

Tablet-Based Sensor: A Stable and User-Friendly Tool for Point-of-Care Detection of Glucose in Urine

The colorimetric detection of glucose in urine through enzymatic reactions offers a low-cost and non-invasive method to aid in diabetes management. Nonetheless, the vulnerability of enzymes to environmental conditions, particularly elevated temperatures, and their activity loss pose significant challenges for transportation and storage. In this work, we developed a stable and portable tablet sensor as a user-friendly platform for glucose monitoring. This innovative device encapsulates glucose oxidase and horseradish peroxidase enzymes with dextran, transforming them into solid tablets and ensuring enhanced stability and practicality. The enzymatic tablet-based sensor detected glucose in urine samples within 5 min, using 3,3′,5,5′-tetramethylbenzidine (TMB) as the indicator. The tablet sensor exhibited responsive performance within the clinically relevant range of 0–6 mM glucose, with a limit of detection of 0.013 mM. Furthermore, the tablets detected glucose in spiked real human urine samples, without pre-processing, with high precision. Additionally, with regard to thermal stability, the enzyme tablets better maintained their activity at an elevated temperature as high as 60 °C compared to the solution-phase enzymes, demonstrating the enhanced stability of the enzymes under harsh conditions. The availability of these stable and portable tablet sensors will greatly ease the transportation and application of glucose sensors, enhancing the accessibility of glucose monitoring, particularly in resource-limited settings

Synthesis, Antibacterial, and Antifungal Activities of Novel Pyridazino Carbazoles

Strategy to synthesize novel carbazole, that is, 2,3-dihydro-2-phenyl-6H-pyridazino[4, 5-b]carbazole-1,4-dione (2), is developed as key reaction. This novel compound showed ideal reactivity toward different functional groups like methyl, carboxylic, nitro, piperazine, and amine; thus series of its derivatives are synthesized sequentially with the aim to fuel up the carbazole compounds with new versatile derivatives. All compounds were investigated for their activity against bacteria (MRSA and S. typhi) and fungi (Candida albicans). Among tested compounds 3, 6, and 8 exhibited pronounced antibacterial activities while 2, 5, and 9 also showed moderate activities. 2, 3, 5, 7, and 9 showed stronger antifungal activity against Candida albicans comparable to positive control

Green synthesis of novel spiropyrazoline-indolinones in neutral deep eutectic solvents and DFT studies

Novel spiropyrazoline-indolinones (4a–t) have been synthesized successfully in neutral deep eutectic solvents by reacting 5-Cl/Br-isatin (1a–b) with aromatic ketones (2a–b) and a variety of substituted hydrazines (3a–e) in good to excellent yields. This eco-friendly straightforward synthetic protocol discloses good functional group compatibility. The conventional synthetic approach was compared with the greener route of microwave-assisted synthesis of spiropyrazolines using ethanol. This approach utilized mild reaction conditions which furnished high yields in short reaction time employing one pot two-step multicomponent. All new compounds were structurally confirmed by detailed spectroscopic analysis and density functional theory calculations. This method provides efficient access to spiropyrazole derivatives using biodegradable and green solvent