Synthesis and FKBP binding of small molecule mimics of the tricarbonyl region of FK506

Abstract

Small acyclic model compounds were synthesized to examine the importance of the C(9) carbonyl group of KF506 for FKBP binding. 4-(4′-Methoxyphenyl)-1-butyl (3″, 4″, 5″-trimethoxyphenylglyoxyl) pipecolate (compound 2d), containing the N-(glyoxyl)pipecolate motif of FK506, was found to bind to FKBP with IC 50 of 16 μM. Replacement of the carbonyl group at the position corresponding to C(9) of FK506 with small nonpolar groups (hydrogen, methylene or methyl group, compounds 2a–2c) significantly reduced the binding affinity.