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An ultrasonic-assisted synthesis of bis-isoxazole derivatives was developed. Eight 3-(6-chloropyridin-3-yl)-5-{[(3-arylisoxazol-5-yl)methoxy]methyl}isoxazoles were synthesized by 1,3-dipolar cycloaddition reaction between substituted isoxazolyl alkyne compounds and 6-chloro-N-hydroxynicotinimidoyl chloride. The structures of the synthesized compounds were confirmed by HRMS, FTIR, 1H and 13C NMR spectroscopy. Wherein, the antifungal and antibacterial activities of target compounds were tested. The synthesized compounds 6a and 6h exhibited better antifungal activity in comparison with the standard drug itraconazole. The minimum inhibitory concentrations(MICs) of both compound 6a and compound 6h were both 4 µg/mL against Candida albicans ATCC 10231.

An efficient and facile method was introduced for the synthesis of benzimidazoles in this paper. The optimum reaction conditions were determined. A series of benzimidazoles bearing phenolic hydroxyl(2a—2t) were synthesized in moderate to excellent yields starting from differently substituted hydroxyl benzaldehyde and 4-position substituted o-phenylenediamine vianu-cleophilic addition in the presence of catalyst Na2S2O5under microwave irradiation condition. Herein, effects of the catalyst, molar ratio of reactants, reaction temperature and solvent were investigated. The optimal reaction condition was determined. The effect of DMF and EtOH solvent on the reaction was compared. The synthesized compounds were characterized by FTIR, HRMS, 1H NMR and 13C NMR spectroscopy. Further, the bacteriostatic activities of the synthesized compounds were evaluated with ciprofloxacin and itraconazole as a positive control, respectively. Compounds 2b, 2n, 2q and 2r exhibited some antibacterial activity. The lowest MIC of antibacterial activity of compound 2b was 32 µg/mL. Meanwhile, the luminescence property of compound 2b was studied. The antibacterial activity of compound 2b, along with their good fluorescence performance highlighted the potential of these compounds as lead structures and owned fluorescence trace for further study towards the development of novel drugs and functional mechanisms in living organisms.

Two new compounds, 4-(2-bromophenyl-4,5-diphenyl-imidazol-1-yl)aniline(probe 1) and 4-[2,4,5-tris(4-bromophenyl)-1H-imidazol-1-yl]aniline(probe 2), were synthesized viaa soft and high-efficiency one-pot microwave- assisted method under solvent-free conditions. Their sensing to different metal ions was detected by UV spectrophotometry and fluorescence spectrometry. Probe 2revealed highly selective and sensitive UV and fluorescence response to Fe3+ion. Upon the addition of Fe3+ion, probe 2showed obvious color change of the solution, conspicuous absorbance enhancement and relatively quick fluorescence quenching. The detection limit for Fe3+ion was respectively calculated to be 0.72 μmol/L(fluorescent detection) and 0.48 μmol/L(UV-spectrum detection). Also, probe 2was bound by Fe3+ion to form a 1:1 complex. Moreover, preliminary application of probe 2for detecting Fe3+ion in aqueous solution was attempted, and satisfying results were obtained.

A small molecule fluorescent probe, 4-[2-(4-chlorophenyl)-4,5-diphenyl-1H-imidazol-1-yl]aniline(L) for detecting Ag+ion was gently synthesized viaone-pot multi-component reaction catalyzed by H3[PW12O40] under solvent-free microwave irradiation. When the concentration of Ag+ ion changed from 0 to 8.0×10−6mol/L in the solution of H2O/CH3OH(19:1, volume ratio), the fluorescence emission spectrum was blue-shifted and accompanied by a gradual increase in fluorescence intensity with a low detection limit of 3.0×10−11mol/L. Moreover, UV-Vis absorption titration experiment demonstrated a 1:1 stoichiometric ratio and an association constant of (9.95±0.44)×105L/mol between probe L and Ag+ion, and thus their complexation mechanism was also proposed and verified. More importantly, this fluorescent probe was remarkably specific for Ag+ion under the interference of other metal ions and exhibited a wide pH application range of 4.0―8.0. Additionally, preliminary application of this probe was also carried out and satisfactory results were shown.