A new class of fluorinated 5-pyrrolidinylsulfonyl isatin caspase inhibitors for PET imaging of apoptosisElectronic supplementary information (ESI) available: Synthetic methods, experimental data, radiolabelling conditions and procedures, details of enzyme assay. See DOI: 10.1039/c2md20249b

Thirteen compounds in a new class of fluorinated 5-pyrrolidinylsulfonyl isatin derivatives were synthesised that have potent and selective inhibitory activity against effector caspases-3 and -7. With in vivo animal PET imaging studies of cerebral ischemia being planned, N -benzylation with selected para -substituted benzylic halides allowed systematic variation of lipophilicity (logP 1.94-3.31) without decreasing inhibition potency (IC 50 ). From this series the p -methoxybenzyl analogue was selected for initial 'proof-of-concept' [ 18 F]-fluoride radiolabelling which proceeded in good yield and purity with no need for a protection/deprotection strategy. Synthesis, in vitro caspase inhibition and [ 18 F]-radiolabelling of a new series of fluorinated 5-pyrrolidinylsulfonyl isatins.