Green N-Methylation of Electron Deficient Pyrroles with Dimethylcarbonate

The N-methylation of electron-deficient pyrroles was affected using dimethyl carbonate in the presence of DMF and catalytic DABCO. This alkylation methodology has proven useful for the alkylation of a variety of pyrroles in 72−98% yields and is considered to be greenchemistry relative to the more common use of methyl halides or dimethyl sulfate.

Michael L. Laurila , Nicholas A. Magnus * andMichael A. Staszak *

Eli Lilly and Company, Chemical Product Research and Development Division, Indianapolis, Indiana 46285, U.S.A

Org. Process Res. Dev., 2009, 13 (6), pp 1199–1201

DOI: 10.1021/op900256t

Publication Date (Web): October 26, 2009

Herein, the N-methylation of compound 1 along with a number of commercially available pyrrole derivatives using DMC, DMF and catalytic 1,4-diazabicyclo[2.2.2]octane (DABCO) are described.