Novel 99m Tc(CO) 3 Complexes with WAY-100635 Moiety for the Development of 5-HT 1A Receptor lmaging Agent

The aim of this study is to develop and synthesize 5-HT 1A receptor imaging agents with WAY-100635 moiety and 99m Tc(CO) 3 core. WAY-100635 is commonly known as 5-HT 1A antagonist and its labeled compound ([ 11 C] WAY-100635) has been used as effective radioligand for imaging brain 5-HT 1A receptors with PET(Positron Emission Tomography). However, there are several restrictions in using a radioisotope of C-11 and requires for more effective radioisotopes and ligands. In order to produce a structure most similar to WAY-100635, WAY-100635 derivatives containing a cysteine chelator were designed and confirmed by using in silico (Hyperchem). The novel compounds (7a, 7b, 7c) were prepared in five or 7 steps with yields of 16%, 36% and 42%, respectively and radiolabeled with [ 99m Tc(CO) 3 (H 2 O) 3 ] The labeling yield was 99% for all the newly synthesized compounds. [ 99m Tc(CO) 3 ]-WAY-100635 derivatives show a neutral charge which were confirmed by paper electrophoresis.