Quantitative structure-activity relationships in bacterial and abiotic alkaline hydrolyses of para-substituted acetanilides
1993
Sorci, J.J. | Macalady, D.L.
Quantitative structure-activity relationships were established for bacterial and abiotic alkaline hydrolysis of acetanilide, 4-bromoacetanilide, 4-cyanoacetanilide, 4-fluoroacetanilide, 4-methoxyacetanilide, 4-methylacetanilide, and 4-nitroacetanilide. The influence of ring substituents on hydrolysis rates was investigated using alkaline solutions and pure bacterial cultures isolated from soil. For an Arthrobacter species, second-order rate constant, kb, for bacterial hydrolysis ranged from (1.09 +/- 0.01) X 10(-14) to (2.62 +/- 0.03) X 10(-14) L organism-1 s-1 for 4-cyanoacetanilide and acetanilide, respectively, showing little sensitivity to substituent effects. Acetanilides were hydrolyzed to the corresponding anilines. Regression of log kb with van der Waals radii of individual substituents yielded a correlation coefficient (r2) of 0.904. Substituent size and geometry, rather than any electronic property, influenced biologically mediated hydrolysis rates. Alkaline hydrolysis rates were controlled by electronic effects (r2 = 0.847). Biotic and abiotic hydrolysis rates did not correlate (r2 = 0.37), indicating these processes are controlled by different parameters.
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