Synthesis and Biological Evaluation of ~(99)Tc~m Labeled Benzamides for Dopamine D2 Receptor Imaging

S) (-) 5 mercapto N ((1 ethyl 2 pyrrolidinyl)methyl) 2 methoxy benz amide MBZM is synthesized by introducing a mercapto group at 5 position of benzene ring to mimic sulpiride ligand.Through the “3+1”mixed ligand approach, a neutral radiolabeled compound 99 Tc m MBZM is also prepared as a potential D2 receptor imaging agent. 99 Tc m MBZM exhibites a fast clearance in blood and higher uptake in the liver and kidney (2.148 and 2.184 %ID/g at 30 min respectively) but low initial brain uptake (only 0.145 %ID/g at 2 min).The results preclude 99 Tc m MBZM from making a brain receptor agent.