QUANTITATIVE STRUCTURE-ACTIVITY-RELATIONSHIPS IN BACTERIAL AND ABIOTIC ALKALINE HYDROLYZES OF PARASUBSTITUTED ACETANILIDES

Quantitative structure-activity relationships were established for bac terial and abiotic alkaline hydrolysis of acetanilide, 4-bromoacetanil ide, 4-cyanoacetanilide, 4-fluoroacetanilide, 4-methoxyacetanilide, 4- methylacetanilide, and 4-nitroacetanilide. The influence of ring subst ituents on hydrolysis rates was investigated using alkaline solutions and pure bacterial cultures isolated from soil. For an Arthrobacter sp ecies, second-order rate constant, k(b), for bacterial hydrolysis rang ed from (1.09 +/- 0.01) x 10(-14) to (2.62 +/- 0.03) X 10(-14) L organ ism-1 s-1 for 4-cyanoacetanilide and acetanilide, respectively, showin g little sensitivity to substituent effects. Acetanilides were hydroly zed to the corresponding anilines. Regression Of log k(b) with van der Waals radii of individual substituents yielded a correlation coeffici ent (r2) of 0.904. Substituent size and geometry, rather than any elec tronic property, infuenced biologically mediated hydrolysis rates. Alk aline hydrolysis rates were controlled by electronic effects (r2 = 0.8 47). Biotic and abiotic hydrolysis rates did not correlate (r2 = 0.37) , indicating these processes are controlled by different parameters.