Synthesis, Characterization and Antibacterial Properties of Dihydroxy Quaternary Ammonium Salts with Long Chain Alkyl Bromides

Five N-methyl-N-R-N,N-bis(2-hydroxyethyl) ammonium bromides (R=-benzyl (chloride, BNQAS), -dodecyl (C12QAS), -tetradecyl (C14QAS), -hexadecyl (C16QAS), -octadecyl (C18QAS)) were prepared based on N-methyldiethanolamine (MDEA) and halohydrocarbon. Five QAS were characterized by FTIR, NMR, and MS. BNQAS, C12QAS, C14QAS, and C16QAS were confirmed by X-ray single-crystal diffraction. Their antibacterial properties indicated good antibacterial abilities against E.coli, S.aureus, B.subtilis, especially C12QAS with the best antibacterial ability (100% to E.coli, 95.65% to S.aureus, and 91.41% to B.subtilis). In addition, C12QAS also displayed the best antifungal activities than BNQAS and C18QAS against Cytospora mandshurica, Botryosphaeria ribis, Physalospora piricola, and Glomerella cingulata with the ratio of full marks. The strategy provides a facile way to design and develop new types of antibacterial drugs for application in preventing the fruit rot, especially apple.