Abstract
The authors experimented with the relation between the position and number of chlorine substitution in naphthol and toxicity against mice. It was found that the toxicity decreased considerably by the substitution of chlorine at para position to OH radical, the decrease being at maximum when the number of Cl substituent is one. In vitro test of 4-chloro-1-hydroxynaphthalene showed this compound to be the best insecticide among chloronaphthol compounds. The chlorine compounds of naphthoquinone possessed low insecticidal action but had a powerful toxicity against higher animals so that unless a compound of excellent insecticidal power can be found, this group of compounds do not seem to be practicable. Observations on the relations between anthelmintic properties and OH radical showed that acylation of OH radical to remove irritation was of no avail and that free OH radical was necessary in such a compound.
