N-Methylation of poorly nucleophilic aromatic amines with dimethyl carbonate

Abstract

Abstract: Dimethyl carbonate (DMC), an environmentally friendly methylation agent, is a substitute for traditional methylation agents such as methyl halides (CH3X, X = I, Br, Cl) or dimethyl sulfate. An efficient, convenient, and green method has been developed for N-methylation of poorly nucleophilic aromatic amines with DMC. It was found that the couple PEG400/K2CO3 provides good selectivity for the N-methylation product. Finally, the mechanism for reaction of amines with DMC was investigated, and a plausible multistep mechanism proposed and verified. Graphical Abstract: [Figure not available: see fulltext.]