A new high-yield synthetic route to PET CB1 radioligands [11C]OMAR and its analogs

OMAR analogs reference standards and their corresponding desmethylated precursors were synthesized from substituted anilines either in 4 and 5 steps with 27–32% and 24–31% yield, or in 3 and 4 steps with 21–30% and 19–28% yield, respectively. [11C]OMAR and its analog radioligands were prepared from their desmethylated precursors with [11C]CH3OTf through O-[11C]methylation and isolated by HPLC combined with solid-phase extraction (SPE) in 50–65% radiochemical yields based on [11C]CO2 and decay corrected to end of bombardment (EOB), with 370–740 GBq/μmol specific activity at EOB.

Graphical abstractA new high-yield synthetic route to PET CB1 radioligands [11C]OMAR and its analogs is presented.Figure optionsDownload full-size imageDownload as PowerPoint slide