A synthetic methodology for the specific conversion of primary aromatic amines into their N-monomethyl derivatives under very mild conditions is presented. Anilines are treated with 4-nitrobenzenesulfonyl (nosyl) chloride to generate the corresponding sulfonamides 2 in high yields. The subsequent N-methylation reaction of the sulfonamides 2 with a solution of diazomethane is rapid and quantitative. Removal of the nosyl protecting group is readily carried out using the reagent system mercaptoacetic acid/1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) affording the N-monomethylated aromatic amines 4. The procedure is convenient, efficient, and gives rise to the N-monomethyl-anilines exclusively.
Highly specific N-monomethylation of primary aromatic amines
LEGGIO, Antonella;LIGUORI, Angelo
2006-01-01
Abstract
A synthetic methodology for the specific conversion of primary aromatic amines into their N-monomethyl derivatives under very mild conditions is presented. Anilines are treated with 4-nitrobenzenesulfonyl (nosyl) chloride to generate the corresponding sulfonamides 2 in high yields. The subsequent N-methylation reaction of the sulfonamides 2 with a solution of diazomethane is rapid and quantitative. Removal of the nosyl protecting group is readily carried out using the reagent system mercaptoacetic acid/1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) affording the N-monomethylated aromatic amines 4. The procedure is convenient, efficient, and gives rise to the N-monomethyl-anilines exclusively.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.