Total synthesis and evaluation of [18F]MHMZ.

Abstract Radiochemical labeling of MDL 105725 using the secondary labeling precursor 2-[ 18 F]fluoroethyltosylate ([ 18 F]FETos) was carried out in yields of ∼90% synthesizing [ 18 F]MHMZ in a specific activity of ∼50 MBq/nmol with a starting activity of ∼3 GBq. Overall radiochemical yield including [ 18 F]FETos synthon synthesis, [ 18 F]fluoroalkylation and preparing the injectable [ 18 F]MHMZ solution was 42% within a synthesis time of ∼100 min. The novel compound showed excellent specific binding to the 5-HT 2A receptor ( K i  = 9.0 nM) in vitro and promising in vivo characteristics.