Synthesis and microbiological properties of novel bis-quaternary ammonium compounds based on 4,4′-oxydiphenol spacer

Novel gemini (tail–head–spacer–head–tail) bis-quaternary ammonium compounds with a 4,4′-oxydiphenol spacer between two pyridinium heads were synthesized and compared with commonly used antiseptics such as benzalkonium chloride and chlorhexidine gluconate. Analogues bearing C₈H₁₇, C₉H₁₉ and C₁₀H₂₁ aliphatic groups displayed potent broad spectrum in vitro activity against five bacterial strains and two fungi, with minimum inhibtory concentrations relatively independent of the counter ion.