One-pot Synthesis and Photophysical Studies of Α-cycloamino-substituted 5-aryl-2,2'-bipyridines.

A series of α-cycloamine substituted 2,2'-bipyridines 3ae'-3ce' was obtained via the one-pot approach based on ipso-substitution of a cyano-group in 1,2,4-triazines, followed by aza-Diels-Alder reaction in good yields. Photophysical properties, including fluorosolvatochromism, were studied for 3ae'-3ce' and were compared with α-unsubstituted 2,2'-bipyridines. In addition, dipole moments differences in ground and excited states were calculated by both Lippert-Mataga equation and DFT studies and were compared to each other. The correlation between the size of cycloamine unit and the dipole moments differences value (based on Lippert-Mataga equation) was observed. In addition charge transfer indices (DCT, Λ, H and t) were calculated to demonstrate influence of molecular structure on the intramolecular charge transfer degree.

Recent Trends in the Antidiabetic Prominence of Natural and Synthetic Analogues of Aurones.

Natural products are a boundless source for the development of pharmaceutical agents against a wide range of human diseases. Accordingly, naturally occurring aurones possess various biological benefits, such as anticancer, antioxidant, antimicrobial, antidiabetic, anti-inflammatory, antiviral and neuroprotective effects. In addition, various studies have revealed that aurones are potential templates for the regulation of diabetes mellitus and its associated complications. Likewise, certain aurones and their analogues have been found to be remarkable kinase inhibitors of DARK2, PPAR-γ, PTPM1, AGE, α-amylase and α-glucosidase, which represents a promising approach for the treatment of chronic metabolic disorders such as diabetes. Therefore, in our present study, we provide a detailed account of the advances in aurones as antidiabetic agents over the past decade.

Mechanosynthesis of Polyureas and Studies of Their Responses to Anions.

Polyureas (PUs) have already found wide practical applications, and various methods of their synthesis have been reported. In this manuscript, we wished to report the very first mechanochemical approach towards aromatic PUs via reactions between isomeric 2,2'-, 3,3'-, and 4,4'-diaminobiphenyls and triphosgene under solvent-free conditions following ball-milling. By using this synthetic approach, both PUs and azomethine-capped Pus were obtained. The fluorescence response of the above-mentioned PUs towards various anions in solutions were studied and selective fluorescence responses towards the hydroxyl and fluoride anions were observed.

(1-(4-(5-Phenyl-1,3,4-oxadiazol-2-yl)phenyl)-1H-1,2,3-triazol-4-yl)-methylenyls α,ω-Bisfunctionalized 3- and 4-PEG: Synthesis and Photophysical Studies.

Two new azaheterocycle-based bolas, such as (1-(4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl)-1H-1,2,3-triazol-4-yl)-methylenyls α,ω-bisfunctionalized PEGs, were prepared via Cu-catalyzed click reaction between 2-(4-azidophenyl)-5-(aryl)-oxadiazole-1,3,4 and terminal ethynyls derived from PEG-3 and PEG-4. Due to the presence of two heteroaromatic cores and a PEG linker, these bola molecules are considered as promising fluorescent chemosensors for electron-deficient species. As a result of a well-pronounced "turn-off" fluorescence response towards common nitro-explosive components, such as 2,4-dinitrotoluene (DNT) and 2,4,6-trinitrotoluene (TNT), hard-to-detect pentaerythritol tetranitrate (PETN), as well as Hg2+ cation was observed.

Diversity of fungal isolates from fungus-growing termite Macrotermes barneyi and characterization of bioactive compound from Xylaria escharoidea.

Owing to their potential applications, as well as their structural diversity, the discovery of novel secondary metabolites from insect-associated fungi has been of interest to researchers in recent years. The aim of this study was therefore to estimate the diversity of fungi associated with fungus-growing termites and bioprospecting these for potential secondary metabolites. In total, 18 fungal species were isolated and described from the gut and comb of Macrotermes barneyi based on 18S ribosomal DNA gene sequence analysis. Antimicrobial activity assays were carried out on all the known fungi, and nine isolates were recorded as active against pathogenic fungi. Xylaria escharoidea, the best performing isolate, was grown at laboratory scale and 4,8-dihydroxy-3,4-dihydronaphthalen-1(2H) was isolated and characterized. The minimum inhibitory concentration of this isolated compound against tested pathogenic organisms was found to be 6.25 µg. In addition, molecular docking studies have revealed that 4,8-dihydroxy-3,4-dihydronaphthalen-1(2H) is a prominent antibacterial agent with a marked interaction with key residues on protein A (agrAC ) that regulates the accessory gene. The findings of this study support the drug discovery of antimicrobial properties in insect-associated fungi, which may lead to novel secondary metabolites.