Predictive correlations for the toxicity of alkyl- and halogen- substituted phenols.

The structure-activity relationships between toxicity (log BR), monitored as cell population growth, and the log 1-octanol/water partition coefficient (log Kow) for a series of 20 alkyl- and halogen-substituted phenols have been examined. The equation log BR = 0.9455 log Kow -1.9190 has been found to be an excellent linear model for these compounds. It explains 93.8% of the variability in toxicity. Subdivision of the tested derivatives based on substituent field electronic effects reveals that those with electron-releasing effects, e.g. methyl or ethyl groups, are slightly less toxic than those with electron-withdrawing effects, e.g. halogen groups.