The reaction of ω (4 hydroxyaryl)haloalkanes with various nitrogen containing agents afforded primary, secondary, and tertiary amino derivatives of 2,6 dialkylphenols. For the compounds synthesized, the reaction rate constants with peroxide radicals were measured for cumene and methyl oleate oxidation. The total inhibitory activity in the model reactions of thermal autooxidation of lard and hexadecane was studied. The rate constants of alkyl(hydr oxylaryl)amines are the same as those of the corresponding alkylphenols, whereas the total inhibitory activity of some alkyl(hydroxylaryl)amines exceeds substantially that for alkylphenols. Alkyl(hydroxyaryl)amines (aminoalkylphenols) are highly efficient inhibitors for free radical oxidation of vari ous organic substrates. According to patent data, 1-4 they can be used as stabilizers of polymeric materials, rubbers, lubricants, and diesel and jet fuels. In addition, alkyl(hydr oxyaryl)amines and their salts possess a high spectrum of biological activity, in particular, they manifest antiphlo gistic, 5 antiarrhythmic, 6 radioprotective, and antitumor 7 properties. At the same time, regularities of changes in the antioxidation activity of alkyl(hydroxyaryl)amines de pending on their structure are insufficiently studied: these data are presented only in few studies 8-12 devoted pre dominantly to benzylic compounds.In the present study, we synthesized structurally re lated series of alkyl(hydroxyaryl)amines 1-6 and studied comparatively their antioxidation activity in various model systems.
Results and DiscussionTertiary amines 1-3 were synthesized by the reac tions of the corresponding ω (4 hydroxyaryl)chloro alkanes 7 with dialkylamines in yields up to 90% (Scheme 1). Scheme 1 7: R = R´ = Bu t , n = 2 (a), 3 (b), 4 (c); R = Bu t , R´ = H, n = 3 (d); R = R´ = Me, n = 3 (e); R = R´ = H, n = 3 (f); R = R´ = cyclo C 6 H 11 , n = 3 (g); R = Bu t , R´ = Me, n = 3 (h); R = R´ = Bu t , n = 5 (i)Secondary amines 4a-c and 5a-c were synthesized similarly in 60-72% yields by the reactions of chloro alkanes 7 with methyl and propylamines.Primary amines 6а-с were synthesized from bromo alkanes 8а-с through intermediate alkylphthalimides 9а-с (Scheme 2). * Dedicated to the memory of Academician N. N. Vorozhtsov on the 100th anniversary of his birth. R = R´ = Bu t , n = 2 (a), 3 (b), 4 (c); R = Bu t , R´ = H, n = 3 (d); R = R´ = Me, n = 3 (e); R = R´ = H, n = 3 (f); R = R´ = cyclo C 6 H 11 , n = 3 (g); R = Bu t , R´ = Me, n = 3 (h); R = R´ = Bu t , n = 5 (i) R″ = Me (1a-i, 4a-c), Et (2a-f), Pr (3a-d, 5a-c), H (6a-c)