A number of dual domain, macrocyclic FKBP12 ligands were synthesised i
n which the FK506 effector domain was fused to simplified FKBP12 bindi
ng domains. The resulting macrocyclic compounds possessed moderate bin
ding affinities for FKBP12 but showed no activity in an assay for FKBP
l2 dependent calcineurin inhibition.