A Mini-Review: Recent Advances in Coumarin-Metal Complexes With Biological Properties.

The coumarin nucleus is a recurring motif in both natural and synthetic compounds that exhibit a broad spectrum of biological properties including anticoagulant, anti-inflammatory, antioxidant, antiviral, antimicrobial and anticancer agents as well as enzyme inhibitors. On the other hand, it has been reported that the incorporation of a metal ion into coumarin derivatives can increase the activity of such complexes compared to coumarin-based ligands. Accordingly, some of them have been found to display promising antioxidant, antitumor or antibacterial activities. This mini-review briefly summarizes the recent development of coumarin-metal complexes with proven biological properties. The attention is also paid to agents for which practical applications in the detection of biologically important species may be found.

Synthesis and Fluorescent Properties of Novel Isoquinoline Derivatives.

Isoquinoline derivatives have attracted great interest for their wide biological and fluorescent properties. In the current study, we focused on the synthesis of a series of novel isoquinoline derivatives substituted at position 3 of the heteroaromatic ring. Compounds were obtained in a Goldberg-Ullmann-type coupling reaction with appropriate amides in the presence of copper(I) iodide, N,N-dimethylethylenediamine (DMEDA), and potassium carbonate. The structures of novel isoquinolines were confirmed by IR, NMR, and elemental analysis, as well as X-ray crystallography. In the course of our research work, the visible fluorescence of this class of compounds was observed. The above findings prompted us to investigate the optical properties of the selected compounds.

Synthesis and Antifungal Activity of Some 4,6-Dimethylisoxazolo[3,4- b]pyridin-3(1H)-one Derivatives.

BACKGROUND: Cutaneous and invasive fungal infections are constant threats to human health that substantiate the need for the development of new efficacious and safe antimycotics. METHODS: A series of N1-alkyl, N1-acyl and N1-sulfonyl derivatives of 4,6- dimethylisoxazolo[3,4-b]pyridin-3(1H)-one (1) were synthesized. The antimicrobial activities of title compounds against 21 pathogenic yeast-like fungal clinical isolates and 5 reference strains were evaluated by means of a broth microdilution method. RESULTS: Among the compounds tested, the newly prepared N1-benzoyl (2m) and N1-(4-fluorobenzoyl) (2n) derivatives of 1 showed 81% and 95% inhibitory efficacy, respectively, against the clinical isolates, which were comparable to that of the reference drug fluconazole. The strains that exhibited the highest susceptibility to the compound 2n included Candida utilis (MIC < 6.2 µg/mL), C. parapsilosis (MIC in the range <6.2 - 12.5 µg/mL), Geotrichum candidum (MIC = 12.5 µg/mL) as well as C. lusitaniae and Rhodotorula mucilaginosa (MIC = 25 µg/mL). CONCLUSION: In terms of MIC, compound 2n proved to be four times more active against the clinical isolates of Candida albicans and C. albicans ATCC 10231 standard strain than fluconazole, the widely prescribed antifungal agent for mucosal and systemic yeast infections (MIC = 50 vs 200 µg/mL).