A convenient method for the conversion of hindered carboxylic acids to N-methoxy-N-methyl (Weinreb) amides.
The conversion of sterically hindered carboxylic acids to N-methoxy-N-methyl amides can be efficiently carried out with 1.1 equiv of methanesulfonyl chloride, 3 equiv of triethylamine, and 1.1 equiv of N-methoxy-N-methylamine. Yields for this process range from 59% to 88%. The major byproduct in these reactions, N-methoxy-N-methylmethanesulfonamide, can be removed by placing the product mixture under vacuum for 14-24 h.
Woo
Jacqueline C S
JC
Department of Chemistry, 2036 Main Mall, University of British Columbia, Vancouver, B.C., Canada V6T 1Z1.
Fenster
Erik
E
Dake
Gregory R
GR
D000577:Amides / Q000138:chemical synthesis*; D002264:Carboxylic Acids / Q000138:chemical synthesis / Q000737:chemistry*; D008968:Molecular Conformation
D000577:Amides; D002264:Carboxylic Acids