Radiosynthesis of 13 N‐labeled thalidomide using no‐carrier‐added [ 13 N]NH 3

Recent studies revealed that thalidomide (1) has unique and broad pharmacological effects on multi‐targets although the application of 1 in therapy is still controversial. In this study, we synthesized nitrogen‐13‐labeled thalidomide ([ 13 N]1) as a potential positron emission tomography (PET) probe using no‐carrier‐added [ 13 N]NH 3 as a labeling agent. By use of an automated system, [ 13 N]1 was prepared by reacting N ‐phthaloylglutamic anhydride (2) with [ 13 N]NH 3 , following by cyclization with carbonyldiimidazole in a radiochemical yield of 56±12% (based on [ 11 N]NH 3 , corrected for decay) and specific activity of 49±24 GBq/µmol at the end of synthesis (EOS). At EOS, 570–780 MBq ( n =7) of [ 13 N]1 was obtained at a beam current of 15 µA after 15 min proton bombardment with a synthesis time of 14 min from the end of bombardment. Using a small animal PET scanner, preliminary biodistribution of [ 13 N]1 in mice was examined. Copyright © 2010 John Wiley & Sons, Ltd.