Chemical structure and properties of selected benzene compounds in relation to biological activity.

Four fundamental physical parameters of series of benzene derivatives were studied to ascertain correlations with biological activity. These included octanol/water coefficient, vapor pressure, infrared absorption (out-of-plane C-H vibration), and the pi values. Each physicochemical constant exhibited a partial correlation with biological activity suggesting that each played a role. It was presumed that more precise and specific data on the biological activity would have permitted a better correlation. It is postulated that the biological activity of a compound is due to the sum of such physicochemical factors as: partition coefficient, molecular geometry and spatial orientation, electronic characteristics of the molecular orbitals, and vibrational-rotational frequencies of constituent groups.