Synthesis and properties of novel stilbene-twelve alkyl quaternary ammonium salts as antibacterial optical whitening agents

Four novel stilbene-twelve alkyl quaternary ammonium salts 5a–d were synthesized. All synthesized compounds were characterized by FT-IR, 1 H-NMR and elemental analysis. Compounds 5a – d showed efficient whitening effect on cotton fiber and high fastness. Furthermore, compound 5c showed better stability to light than C186 in aqueous solution. The preliminary biological experiment demonstrated compounds 5a – d possessed significant antibacterial activities. Among them, compound 5d turned out to be the most active compound against Candida albicans with MIC 50 4 μg/mL as well as E. coli with MIC 50 16 μg/mL.