Inhibition of Streptococcus faecalis by long chain aliphatic monoamines: quantitative structure-activity studies

Primary, secondary, and tertiary long chain aliphatic amines were synthesized, and their activity against Streptococcus faecalis was determined. Quantitative structure-activity analyses were carried out based on the Hansch extrathermodynamic model, using partition coefficients, CMC's, quantum mechanical charges on the amine nitrogen, and the Taft steric parameter. The best correlations were obtained with the CMC. Steric properties of the ammonium head become important for tertiary amines. The structural feature of these compounds that dominates biological activity is the length of the alkyl tail. Ammonium head substituents are of only secondary importance.