The MMP inhibitor (R)-2-(N-benzyl-4-(2-[18F]fluoroethoxy)phenylsulphonamido)-N-hydroxy-3-methylbutanamide: Improved precursor synthesis and fully automated radiosynthesis.

The CGS 25966 derivative (R)-2-(N-Benzyl-4-(2-[(18)F]fluoroethoxy)phenyl-sulphonamido)-N-hydroxy-3-methylbutanamide [(18)F]9 represents a very potent radiolabelled matrix metalloproteinase inhibitor. For first human PET studies it is mandatory to have a fully automated radiosynthesis and a straightforward precursor synthesis available. The realisation of both requirements is reported herein. In particular, the corresponding precursor 8 was obtained in a reliable 7 step synthesis with an overall chemical yield of 2.3%. Furthermore, the target compound [(18)F]9 was prepared with a radiochemical yield of 14.8±3.9% (not corrected for decay).