The use of pentafluorophenyl derivatives for the ¹⁸F labelling of proteins

A simple, one-step method for the radiolabelling of proteins with ¹⁸F is described. A series of pentafluorophenyl derivatives were synthesized and tested for ¹⁸F exchange using tetrabutylammonium-[¹⁸F]fluoride in DMSO, with microwave heating. A number of the compounds examined incorporated ¹⁸F quickly and in high yield. Two compounds, pentafluorobenzaldehyde and 2,3,5,6-tetrafluorophenyl-pentafluorobenzoate, were used to label HSA in good yield. The methods produce low specific activity labelled proteins, but are fast. The yields are reasonable and the reagents do not require a separate modification or activation step for protein labelling.