Novel CNS dopamine D-2 receptors of the formulae (see fig. I) (see fig. II) where Y and Y' are independently selected from the group consisting of hydrogen, C1-C5 alkyl; C1-C5 alkenyl and C1-C5 alkynyl; Z is selected from the group consisting of halogen (Hal), CH=CH-Hal; C1-C10 alkylene-Hal; C1-C10 alkylene-CH=CH-Hal; C1-C10 alkylene-phenyl-Hal; C1-C10 alkylene-heteroaryl-Hal; provided that, in Compounds of Formula I, Hal is a radioactive iodine atom; and A is an alkylene moiety of from two to eight carbon atoms, are disclosed. An example of such a compound is 5-iodo-7-N-¢(1-ethyl-2-pyrrolidinyl)methyl!carboxamide-2,3-dihydrobenzofuran. These compounds are useful as imaging agents for D-2 receptors in the human brain and exhibit good brain retention and in vivo stability.
DOPAMINE RECEPTOR LIGANDS AND IMAGING AGENTS