Ipso-nitration of carboxylic acids using a mixture of nitronium tetrafluoroborate,base and 1-hexyl-3,4,5-trimethyl-1H-imidazolium tetrafluoroborate

An eco-friendly and a simple ipso-nitration protocol for a series of aliphatic and (hetero)aromatic carboxylic acids using nitronium tetrafluoroborate, 1-hexyl-3,4,5-trimethyl-1H-imidazolium tetrafluoroborate and base is reported. While contrasted with recently known decarboxylative ipso-nitration strategies for the preparation of nitro compounds, this protocol does not require a toxic metal catalyst and harmful volatile organic solvents. Moreover, this method is perfect for a broad range of functional groups and affords exclusively the ipso-nitrated product in moderate to good yields.