Synthesis and evaluation of an 18F analog of forskolin for imaging adenylyl cyclase

Abstract We prepared two fluorine containing carbamate analogs of forskolin as potential agents for imaging adenylyl cyclase in the living brain with positron emission tomography. Both compounds display high in vitro affinity for adenylyl cyclase. The radiosynthesis of 7-(2-[ 18 F] fluoroethyl) carbamoyl forskolin from an imidazolyl carbamate utilizes [ 18 F] fluoroethyl amine, prepared by a novel method employing rapid deprotection and requiring no distillation. The brain uptake in rats and monkeys of 7-(2-[ 18 F] fluoroethyl) carbamoyl forskolin is too low to be an effective imaging agent for this second messenger system.