QSAR study of 1,8-naphthyridin-4-ones as inhibitors of photosystem II

The effect of substituents on in vitro activity of 20 1,8-naphthyridin-4-on es, a novel class of photosystem II inhibitors, was studied. A four-paramet er QSAR model based on the molecular connectivity indices was developed whi ch accounts for about 87% of the variations in inhibitory potencies of thes e compounds. The model suggests that the position, size, and polarity of su bstituents are factors that predominantly control their activity. By using physicochemical constants, a quantitative model for both 1,8-naphthyridin-4 -ones and structurally related 2-trifluoromethy-1-4-hydroxyquinoline deriva tives was proposed.