*2.1. General*

All chemicals used within this research were acquired from commercial suppliers. Aluminum TLC plates coated with fluorescent indicator F254 were used for thin-layer chromatography, with benzene:acetic acid:acetone (8:1:1) as an eluent, and checked under a UV lamp (HP-UVIS® UV-analysis lamp, Biostep GmbH –Desaga, Burkhardtsdorf, Germany) on 365 nm and 254 nm. NMR spectra were recorded on Bruker Avance 600 MHz NMR Spectrometer (Bruker Biospin GmbH, Rheinstetten, Germany) at 293 K with DMSO-*d*6 used as a solvent and tetramethylsilane (TMS) as an internal standard. The mass spectra were recorded by LC/MS/MS API 2000 (Applied Biosystems /MDS SCIEX, Redwood City, CA, USA). Melting points were determined with electrothermal melting point apparatus (Electrothermal Engineering Ltd., Rochford, UK). Bacteria strains were isolates from various clinical specimens obtained from Microbiology Service of the Public Health Institute of Osijek-Baranja County, Osijek, Croatia.

#### *2.2. General Procedure for Synthesis of Fluorinated Pyrazoles (***3a**–**j***)*

All compounds were synthesized according to Rostom et al. [18]. Briefly, equimolar amounts of desired acetophenone and aldehyde were mixed together in cold methanol and 50% aqueous NaOH solution was added. The mixture was stirred for 4 h and poured over crushed ice, the product was filtered and dried.

The second step included synthesis of desired compounds from synthesized chalcone, hydrazine hydrate and formic acid under reflux for 10 h. The mixture was cooled, the obtained precipitate filtered and dried.
