Effects of adenine nucleotides on oxidation of phenothiazine tranquilizers.

The effects of adenosine diphosphate and triphosphate on the periodic acid oxidation of the phenothiazine tranquilizing drugs were studied. The principal effect was a marked reduction in the rate of formation and decay of the drug free radical. The oxidation rates of the nucleotide free drugs seemed to be most strongly influenced by the inductive effects of substituents at the 2-position of the phenothiazine nucleus. However, the oxidation rates of the drugs in the presence of nucleotide were most strongly influenced by the substituents at the 10-position. Variations of the structure of substituents at the 10-position have only a modest effect on the electronic state of the phenothiazine nucleus. Therefore, the marked effect of structural variation in the 10-substituents in the presence of nucleotide on the periodate oxidation rate most likely is an expression of steric effects related to an interaction between drug and nucleotide.