Rapid synthesis of 11C-labeled FK506 for positron emission tomography

The present study describes a rapid synthesis method for labeled [11C]FK506 for positron emission tomography (PET). A one-pot reaction from [11C]CH3I, involving a Wittig reaction as the key carboncarbon bond formation was developed. The chemical process was accomplished using a designed, fully automated synthetic apparatus, and an injectable solution of [11C]FK506 was obtained in only 34 min from [11C]CH3I. The decay-corrected radiochemical yield based on [11C]CH3I was 11.9%, and the specific activity was 39.8 GBq/μmol.