Selective N-methylation of primary aliphatic amines with dimethyl carbonate in the presence of alkali cation exchanged Y-faujasites
作者:Maurizio Selva、Pietro Tundo
DOI:10.1016/j.tetlet.2003.09.016
日期:2003.10
The N-methylation of aliphatic amines [XC6H4(CH2)(n)NH2; n = 1, X = H (1a), o-MeO (1b), p-MeO (1c); n = 2, X = H (2a), o-MeO (2b); 1d: PhCH(Me)NH2] with dimethyl carbonate (DMC) is efficiently catalysed by NaY faujasite: on condition that CO2 (a co-product of the reaction) is carefully removed, N-methyl- and N,N-dimethyl-amines (RNHMe and RNMe2) are obtained in good overall yields (70-90%). Otherwise, in the presence Of CO2, carbamates (RNHCO2Me) form competitively to a large extent. The reaction probably proceeds through a B(Al)2 displacement of the amine on DMC. (C) 2003 Elsevier Ltd. All rights reserved.