Abstract
Cumene hydroperoxide-supported N-demethylation of aminopyrine catalyzed by catalase has been investigated. The transient free radical of aminopyrine was detected by electron spin resonance at room temperature. 4-Diethylaminoantipyrine was also oxidized to the corresponding free radical. Although another free radical was detected in the absence of aminopyrine in the catalase-cumene hydroperoxide system, this radical is considered not to be the major oxidant of aminopyrine in the catalase-aminopyrine-cumene hydroperoxide system, because its concentration was too low. Cumene hydroperoxide previously added to the catalase solution greatly inhibited the oxidation of aminopyrine, whereas it did not inhibit the catalatic reaction. In contrast, sodium azide significantly inhibited the latter reaction and only slightly inhibited the former reaction. Methanol was not oxidized appreciably in our system. The present study suggests that the active site of catalase for the cumene hydroperoxide-supported N-demethylation of aminopyrine is different from that for the catalatic reaction.
