An efficient, mild and rapid synthesis of α-fluoroketones has been developed, via a fruitful association between gold and Selectfluor starting from aldehyde-yne and alkynylaryl ketone derivatives. Several functionalized and synthetically highly valuable α-fluoroketones (21 compounds, up to 92%) were isolated in good to excellent yields via a remarkable regioselective oxyfluorination reaction in EtOH/H 2 O at room temperature. We have shed some light on parts of the mechanism by reacting diphenylacetylene and aldehyde-yne with or without Selectfluor. The reaction most presumably occurs via a sequential gold-catalyzed regioselective hydration followed by the α-fluorination reaction, but the presence of aldehyde moiety is crucial for the reactivity of alkyne function. The fluoroketones were efficiently transformed to 4fluoroisoquinolines (9 compounds, 82-95%) of high pharmaceutical interest. Scheme 1. Reactions of alkyne derivatives via gold-catalyzed fluorination.

A series of thiosemicarbazones 3a-d and 4-thiazolidinones 5a-d, 7a-d, and 9a-h were synthesized and evaluated for their in vitro antimicrobial activity. Condensation of 3-acetyl-4-hydroxy-6-methyl-2H pyran-2-one1 (dehydroacetic acid) with thiosemicarbazide 2a-d in ethanol at room temperature yielded the thiosemicarbazones 3a-d. These compounds were exploited to synthesize the 4-thiazolidinones 5a-d via their reactions with ethyl 2-bromo propionate4. Derivatives 7a-d were prepared by reaction of the thiosemicarbazones 3a-d with phenyl bromoacetate 6. The 4-thiazolidinones 9a-h were obtained by treatment of compound 3a or 3c with maleimide derivatives 8a-d in refluxing ethanol, under sulfuric acid catalysis. All compounds were screened in vitro for their antibacterial and antifungal activities against five human pathogens microorganisms: Escherichia coli ATCC 25992, Pseudomonas aeruginosa ATCC 27852, Staphylococcus aureus ATCC 43300, Staphylococcus aureus ATCC 25923, and Candida albicans.

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