The Acute toxicity of alpha-branched phenylsulfonyl acetates in Photobacterium phosphoreum test

The acute toxicity (15-min EC(50)) of 20 alpha-substituted phenylsulfonyl acetates was measured using the Microtox test with Photobacterium phosphoreum. On the basis of TLSER, quantitative structure-activity relationships (QSARs) were calculated for the inhibition of bioluminescence. With the parameters molecular volume (V(mc)), dipolarity/polarizability (pi*), and the covalent contribution to Lewis basicity (epsilon(b)), a squared correlation coefficient (r(2)(adj)) of 0.868 and standard error of 0.094 for log EC(50) were obtained. By introducing a structural indicator variable (I), the regressive quality was improved (correlation coefficient of 0.948 and standard error of 0.059); the descriptors V(mc), pi*, and the electrostatic basicity contribution (q(-)) were significant. -NO(2)-- and -SO(2)--groups are active centers of these compounds. The strong hydrogen bonding effects between the compound active centers and FMNH(2) play an important role in the greater toxicity of these chemicals.