SYNTHESIS AND ANTIMICROBIAL CHARACTERISTICS OF HA,OMEGA-POLYMETHYLENEDITHIO)BIS(1-ALKYLPYRIDINIUM IODIDE)S

Bis-quaternary ammonium compounds (bis-QACs), ha,omega-polymethylenedi thio)bis(1-alkylpyridimium iodide)s (4DTBP-m,n), which have 3 to 10 ca rbon atoms in the connecting methylene chain (m) and 8 to 18 carbon at oms of the N-alkyl chain (n), were synthesized. 4D-TBP-6,12 exhibited a wide antimicrobial spectrum against gram-positive and gram-negative bacteria and fungi, The activity was stronger than those of N-dodecylp yridinium iodide (P-12), benzyldodecyldimethylammonium chloride and 2- (4-thiazolyl)benzimidazole. The bactericidal activities of 4DTBP-m,n w ere scarcely affected by the lengths of the alkyl chain and methylene chain, The bis-QAC that showed the highest activity was 4DTBP-6,8 (min imum inhibitory concentration (MIC) = 1.6 mu M, minimum bactericidal c oncentration (MBC)=2.6 mu M), and its activity was about 10 times that of N-hexadecylpyridimium iodide (P-16), which was the most active in the P-n series, In addition, 4DTBP-6,12: showed a high bactericidal ac tivity in the ranges of pH 5 to 8.5 and 10 to 40 degrees C, in contras t to momo-QACs. The bis-QACs synthesized in this study have excellent bactericidal properties.