Synthesis of ketone analogues of prolyl and pipecolyl ester FKBP12 ligands.

The recently discovered small-molecule ligands for the peptidyl and prolyl isomerases (PPIase) of FKBP12 have been shown to possess powerful neuroprotective and neuroregenerative effects. Ketone analogues of the prolyl and pipecolyl esters, which mimic only the FKBP binding domain portion of FK506, are proposed and an efficient synthetic strategy is presented in this report, along with the preliminary results of in vitro and in vivo biological studies.