Benzopyran-2-one derivatives: antiinflammatory, analgesic and antiproteolytic agents

Design, Spectroscopy, and Assessment of Cholinesterase Inhibition and Antimicrobial Activities of Novel Coumarin–Thiadiazole Hybrids

A novel series of coumarin–thiadiazole hybrids, derived from substituted coumarin-3-carboxylic acids was isolated and fully characterized with the use of a number of spectroscopic techniques and XRD crystallography. Several of the novel compounds showed intensive fluorescence in the visible region, comparable to that of known coumarin-based fluorescence standards. Moreover, the new compounds were tested as potential antineurodegenerative agents via their ability to act as acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitors. Compared to the commercial standards, only a few compounds demonstrated moderate AChE and BuChE activities. Moreover, the novel derivatives were tested for their antimicrobial activity against a panel of pathogenic bacterial and fungal species. Their lack of activity and toxicity across a broad range of biochemical assays, together with the exceptional emission of some hybrid molecules, highlights the possible use of a number of the novel hybrids as potential fluorescence standards or fluorescence imaging agents.

Synthesis of New [1,2,4]Triazolo[3,4-b][1,3,4]thiadiazines and Study of Their Anti-Candidaland Cytotoxic Activities

New triazolothiadiazine derivatives5a–hwere synthesized from 4-amino-3-(4-pyridyl)-5-mercapto-4H-1,2,4-triazole (3) with substituted aryl hydrazonoyl chlorides4a–h. The compounds were testedin vitroagainst elevenCandidaspecies and compared with standard drug ketoconazole. Among these compounds, the compounds bearingp-chlorophenyl5e,p-methoxyphenyl5c, phenyl5a,andp-sulphonamidophenyl5gsubstituents on triazolothiadiazine system were found to be the most effective derivatives againstCandidaspecies. Compound5ewas the most effective compound againstC. parapsilosis(ATCC 22019),C. albicans(ATCC 66027),C.specie [blood] 12810, andC.specie [urine] 300 with MIC value of 6.25 μg/mL, whereas ketoconazole exhibits the inhibitory activity with MIC value of 3–30 μg/mL against all tested strains. It was clear that there is a positive correlation between anti-Candidalactivity andp-chlorophenyl substitution on triazolothiadiazine ring. All the synthesized compounds were also investigated for their potential cytotoxicity on noncancer cell line (MCF-12) using WST-1 assay. Three compounds5d,5a,and5hwere found to have the same IC50value as that of standard drug ketoconazole against noncancer cell line MCF-12 (IC50≥ 1.0 × 105 μg/mL).

Synthesis of 4-(3-coumarinyl)-3-benzyl-4-thiazolin-2-one 4-methylbenzylidenehydrazone and determination of the isomeric structure by X-ray analysis

In this study 4-(3-coumarinyl)-3-benzyl-4-thi azolin-2-one 4-methylbenzylidenehydrazone 3 was synthesised. An independent proof of the thiazolylhydrazone structure of 3 was achieved by single crystal X-ray diffraction analysis. Elemental analyses and spectral data (IR, 1H-NMR, 13C-NMR and EIMS) of 3 was also determined. The coumarin ring system and the thiazole ring are almost planar, the dihedral angle between them is 62.93(5)°. The phenyl groups make dihedral angles of 86.09(7) and 31.67(7)° with the thiazole ring plane. The crystal structure is stabilised by intra-, intermolecular hydrogen contacts and C–H...π type interactions.