Structure-Toxicity Relationships of Para-Position Alkyl- and Halogen-Substituted Monoaromatic Compounds

Abstract

The relative toxicity of 46 para-position alkyl- and halogen-substituted pyridines, cyanobenzenes, nitrobenzenes, phenols, benzyl alcohols, and benzaldehydes was determined by measuring the population growth impairment (log BR) of the ciliate Tetrahymena pyriformis. The 1-octanol/water partition coefficient (log KOW)-dependent quantitative structure-activity relationship (QSAR) for the pyridines, cyanobenzenes, and nitrobenzenes is log BR = 0.8222 (log KOW) - 1.7889; n = 19, r2 = 0.937, and s = 0.155. A similar QSAR for the phenols, benzyl alcohols, and benzaldehydes is log BR = 0.6360 (log KOW) - 1.2012; n = 27, r2 = 0.726, and s = 0.284 (where n = the number of data points; r2 = the coefficient of determination; and s = root mean square.) The predictability of the latter QSAR is improved by the addition of the orthogonal field electronic parameter F. The resulting QSAR is log BR = 0.7891 (log KOW) + 0.6793 (F) - 1.7457; n = 27, r2= 0.925, and s = 0.163.