The oxygenation of 4-alkynyl-2,6-di-t-butylphenols (1) promoted by Co(Salpr) resulted in the dioxygen incorporation predominantly into the side chain, whereas in the oxygenation of 1 with t-BuOK in t-BuOH dioxygen was incorporated exclusively into the ortho position. The results are rationalized by a radical process in the former reaction and a nonradical process in the latter oxygenation.
Co(salen)-catalyzed oxidation of 2,4- and 2,6-di-tert-butylphenols bearing an unsaturated side chain, with tert-butyl hydroperoxide (TBHP) in CH2Cl2 at rt, results predominantly in the formation of tert-butylperoxylated products. The position of tert-butylperoxylation depends on the nature of the unsaturated side chain: predominantly the ortho position for 4-alkynyl-2,6-di-tert-butylphenols, the side chain for 4-alkenyl-2,6-di-tert-butylphenols, and the para position for 4-cyano- or 4-(1-methoxyimino)alkyl-2,6-di-tert-butylphenols as well as 2-alkynyl-, 2-alkenyl-, and 2-cyano-4,6-di-tert-butylphenols. The ortho tert-butylperoxylated products arise mainly from initially formed para tert-butylperoxylated products, by migration of the tert-butylperoxy group.
Novel anti-inflammatory agents, pharmaceutical compositions and methods for reducing inflammation