http://www.e-journals.in Chemical Science Transactions DOI:10.7598/cst2014.378 2014, 3(1), 281-291 Synthesis, Characterizationand Antibacterial Activity of Quaternary Ammonium Compounds Bearing Mixed N-Substituted Groups SOFIANE DAOUDI 1 , ADIL A. OTHMAN 1* , TAHAR BENAISSA 2 and ZAHRA OULD KADA 1 1 Laboratory of Bioactive Organic Chemistry, Department of Chemistry, Faculty of Sciences, University of Sciences and Technology of Oran -Mohamed Boudiaf, P.O.Box 1505 El-M’naouer, Oran 31003, Algeria 2 Chemical Physics Laboratory, University of Moulay Tahar, Saida, 20000 Algeria adelaliothman@gmail.com Received 10 September 2012 / Accepted 23 April 2013 Abstract: Sixteen quaternary ammonium bromides [QAB] 4(a-d)-7(a-d)bearing mixed N-branches were synthesized by treating n-butyl 2a, cyclohexyl 2b, 2,3,4,6-tetra-O-acetyl – D- glucosyl 2c and cholesteryl 2d bromides, separately with n-butyl amine 3a, benzyl amine 3b, N,N-dimethyl amino ethyl-2- methyl acrylate 3c and N,N-diethyl amino ethyl-2- methyl acrylate 3d. N,N-Diphenyl amine 3e failed to react with any bromides within the scope of this work. The synthesized bromides and QAB were characterized by FT-IR, 1 H-NMR and 13 C-NMR. All compounds were tested for their activity against some gram-positive and gram-negative bacteria and some of them exhibited significant antibacterial activities. Keywords: Alkyl and cycloalkyl bromides, Benzyl bromides, Dialkylaminomethyl acrylate bromides, Quaternary ammonium compounds, Antibacterial activity Introduction Quaternary ammonium salts [QAS] found in very important life compounds such as amino acids, central nervous system of animals and cationic bile salts 1 . Some synthesized bile salts were used as good cholesterol-lowering agents 2,3 and have also been used as antimicrobials 4 , gall stone dissolution enhancers 5 and DNA transfection agents 6,7 . Several generations of synthetic quaternary ammonium compounds [QAC] which have been used as antimicrobial agents being recognized in the past seven decades. Variations in the four branches attached to quaternary ammonium nitrogen and multiplicity of N + centers were the major features of the classes of QACs 8 . The N-alkyl-N,N-dimethyl ammonium methyl ethyl acrylates 9-13 and N-alkyl-N,N-diethyl ammonium methyl ethyl acrylates 10 are the raw material for dental antibacterial agents. Two of the new groups with good antimicrobial activity are the heterocyclic pipyridinium 14 and glucopyranose QAS 15 . Other increasing applications of QAC were reported in the literature, such as food, beverages preserving agents 16 , fabric 17 , cosmetic 18 , medical 19 , environmental 20 and electrolytes for liquids batteries 21 uses. Because of the increasing resistance of microorganisms to RESEARCH ARTICLE