Synthesis and biological characterization of [H-3] (2-amino-4,5,6,7-tetrahydrobenzo[b]thiophen-3-yl)(4-chlorophenyl)-methan one, the first radiolabelled adenosine A(1) allosteric enhancer

Among the adenosine A1 allosteric enhancers reported so far, compd. (2-amino-4,5,6,7-tetrahydrobenzo[b]thiophen-3-yl)(4-chlorophenyl)methanone (I, named T-62) has shown biol. properties similar to those of PD 81,723, the ref. A1 allosteric enhancer and it has been more fully pharmacol. investigated. The prepn. of the radiolabeled form of compd. I and its characterization by satn. binding expts. are reported. These studies allowed us to demonstrate for the first time the existence of a specific, allosteric site on the A1 receptor.