Iron(II, III)-catalyzed oxidative N-dealkylation of amines with dioxygen

Labile iron complexes (e.g., [Fe-III (bPY)(2)](MecN)(3+), [Fe-II(bPY)(2)](MeCN)(3+), and [Fe-III (H2O)(6)](MeCN)(3+), and [Fe-II(H2O)(6)](MeCN)(2+)) in base-free acetonitrile activate dioxygen for the direct oxygenation of N,N- and N-alkylated amines to form N-dealkylated products and corresponding aldehydes. N,N-dimethylaniline (DMA) is oxidized to N-methylaniline (MA) and formaldehyde as well as to N-methylanilide. Formaldehyde and the excess of substrate undergo condensation reaction to produce 4,4'-methylenebis(NN-dimethylaniline) (MBDME). Small amounts of N-methylformanilide (MF) and formanilide are also formed during oxidation of NN-dimethylaniline and N-methylaniline respectively. Iron(III) catalysts are reduced by the substrate to iron(II), which activates dioxygen. Dioxygen activation step is preceded by the equilibrium reaction between iron(II) catalyst and substrate. (C) 2003 Elsevier B.V. All rights reserved.