, Z)-5-(4-Phenoxybenzylidene)-2-(methylthio)-1H-imidazol-5(4H)-one (33) (4 mmol, 1.19 g) and 3-(4-methylpiperazin-1-yl)propan-1-amine (5 mmol, 0.78 g) were used. Yellow solid. Yield 68%; mp 220-230 ? C. C 24 H 30 ClN 5 O 2 MW 455

3. H-nmr-?-;-m, Ph-3,5-H, Ph'-2,6-H), 6.72 (s, 1H, C = CH), 3.77 (br. s, 2H, N3-CH 2, 7.46-7.36 (m, 4H, Ph-2,6-H, Ph'-3,5-H), 7.15-6.95 (m, vol.4

, 2-yl)methylene)-2-amino-3-(2-(4-methylpiperazin-1-yl)ethyl)-3H-imidazol-4(5H)-one hydrochloride (13) (Z)-5-((9H-Fluoren-2-yl)methylene)-2-(methylthio

, Orange solid. Yield 69.27%; mp 265-267 ? C. C 25 H 30 ClN 5 O MW 451, 35 (br. s, 1H, NH 2 -taut: N1-H), 8.32-7.70 (m, 4H, NH 2 -taut: C2 = NH, vol.9, p.3

, Z)-5-(Biphen-4-ylmethylene)-2-(methylthio)-3H-imidazol-4(5H)-one (35) (2.5 mmol, 0.72 g) and 3-(4-methylpiperazin-1-yl)propan-1-amine (4 mmol, 0.63 g) were used. Yellow solid. Yield 49%; mp 258-260 ? C. C 24 H 30 ClN 5 O MW 439

1. H-nmr-?-;-br.-s and N. +. , 1H, Ph'-4-H), 7.80 (br. s, 2H, NH 2 ), 7.79-7.61 (m, 4H, Ph'-3,5-H, Ph-2,6-H), 7.52-7.30 (m, 4H, Ph'-2,6-H

, -methylpiperazin-1-yl)propyl)-5-(naphthalen-1-ylmethylene)-3H-imidazol-4(5H)-one hydrochloride (15) (Z)-2-(Methylthio)-5-(naphthalen-1-ylmethylene

, ESI) m/z [M+H] + 378.21. 1 H-NMR ? [ppm]: 8.83 (br. s, 1H, NH+), 8.19 (br. s, 2H, taut NH 2, -methylpiperazin-1-yl)propan-1-amine (7 mmol, 1.09 g) were used. Yellow solid. Yield 24%; mp 187-191 ? C. C 22 H 28 ClN 5 O MW 413.94. LC/MS±: purity 99.07% t R = 3.21, vol.1, pp.3-32

, mmol, 1.22 g) and 3-morpholinopropan-1-amine (5 mmol, 0.72 g) were used. Orange solid. Yield 70%; mp 244-246 ? C. C 25 H 27 ClN 4 O 2 MW 450.96. LC/MS±: purity 98, (br. s, 1H, NH + ), 10.21 (br. s, 1H, NH 2 -taut: N1-H), 9.39 (br. s, 1H, NH 2 -taut: C2 = NH), 8.72 (s, 1H, Ar-9-H), 8.25-7.95 (m, 4H

, mmol, 1.55 g) and 3-morpholinopropan-1-amine (7 mmol, 1.01 g) were used. Yellow solid. Yield 41%; mp 227-230 ? C. C 23 H 27 ClN 4 O 3 MW 442.94. LC/MS±: purity 96, 1H, NH + ), 9.45 (br. s, 1H, NH 2 -taut: N1-H), 7.82-7.27 (m, 6H, NH 2 -taut: C2 = NH, vol.37

C. ,

, Refinement and further calculations were carried out using SHELXL [44]. For molecular graphics ORTEP [45] and MERCURY [46] programs were used. Crystallographic data: C 18 H 24 ClN 5 O, M r = 361, Crystallographic Studies Crystals suitable for an X-ray analysis were obtained by slow evaporation of the solvent at room refined without any restraints, vol.87, p.697

, USA) supplemented with 5% sheep blood, respectively. Cation-adjusted Mueller-Hinton (MH II) broth used in the microbiological assays was obtained from bioMérieux. Oxacillin, norfloxacin, chloramphenicol, doxycycline, PA?N, and INT were purchased from Sigma Aldrich, Microbiological Assay S. aureus and E. aerogenes bacteria were maintained and grown on Columbia agar (bioMérieux, vol.1, p.2

®. Tecan and . France, SA-Lyon, France) after overnight incubation at 37 ? C. Experiments were carried out in triplicate and the resulting medians were presented. First, minimum inhibitory concentration (MIC) values of a series of imidazolidine derivatives were examined against S. aureus and E. aerogenes strains. Then, MICs of selected antibiotics were determined in the absence and in the presence of compounds in order to measure the adjuvant-like effect of these structures. In the latter case, compounds tested were evaluated for the ability to enhance antibacterial activity of ?-lactam antibiotic oxacillin in methicillin-resistant and methicillin-susceptible S. aureus (MRSA and MSSA) strains as well as chloramphenicol, erythromycin, doxycycline, Susceptibility Testing Susceptibility testing was performed by the 2-fold standard microdilution method in MH II broth following the Clinical and Laboratory Standards Institute (CLSI) and the Comité de l'Antibiogramme de la Société Française de Microbiologie (CA-SFM) recommendations

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