Tetrahedron Letters,Vol.28,No.29,pp 3387-3390,1987 0040-4039/87 $3.00 + .OO Printed in Great Britain Pergamon Journals Ltd. BASE-CATALYZED AUTOXIDATION OF TRIALKYLAMINES. AN E.S.R. STUDY LORIS GROSS1 Dipartimento di Chimica Organica - Universita Viale Risorgimento 4 - 40136 Bologna, Italy Abstract - When a freshly distilled tertiary alkyl amine is dissolved in water a base-catalyzed oxidative dealkylation process takes place, leading to the formation of secondary nitroxyl radicals, alkenes and carbonyl-containing com- pounds. Oxidative processes involving reactions of molecular oxygen with organic matter are of considerable biological and industrial importance, and extensive literature exists on this subject. l-4 However, most of the work deals with autoxidations in neutral or acidic media while base-catalized reactions have been less investigated. Although amines are not temperature5 in ,:e,rme.;;',",c~~f raccattiayys;;,thmolecular oxygen (at ambient certain structural features do favour oxidation. However, the autoxidation of amines, particularly those derived from tertiary systems, is not very well understood6 For example, there is the ambiguity as for the primary oxidation step; some authors propose that either an electron from nitrogen or an a-hydrogen may be removed. In the former mechanism, a nitrogen centered cation radical is formed followed by a loss of an a-proton to generate a C-centered radical \+. I a) \ N-AH 22-+ N-CH ZH--, \ ./ / I / I / N-C, In the latter, the a -aminoalkyl radical can be formed by direct abstraction of \ I b) ,N-YH -H. \ */ -----* N-C / \ an a-hydrogen by other free radicals during autoxidation. With the exception of some photochemical oxidations and with the possible exception of certain organometallic compounds, the liquid-phase autoxidation of most organic substances by atmospheric oxygen is a free-radical chain process e 1 ement aryvr~~cy~on~y~xy radlcal s ’ and it can be represented by well known This paper reports evidences of a novel autoxidation process induced by atmospheric oxygen on trialkylamines in basic media. RESULTS A large number of tertiary alkyl amines/H20 systems were investigated and all 3387