Homolytic substitution by the ln-undecyl radical at positions 2 and 4 of the pyridine nucleus results from thermal decomposition of dodecanoyl peroxide in acetic acid. Rate dependence on pH shows that pyridine protonation increases the rate of addition of the alkyl radical to the pyridine ring but decreases the rate of the reaction of the intermediate radical with the peroxide. Results are interpreted in terms of orbital interaction theory.
