11C-radiolabeling of hallucinogenic psilocin, a potential radioligand for studying the role of serotonin receptors in psychotic symptom formation

Abstract

The desmethyl compound, 4-hydroxy-N-methyltryptamine (4), was synthesized via a four-step reaction sequence starting from 4-benzyloxyindole (1). Psilocin (4-hydroxy-N,N-dimethyltryptamine), an indole hallucinogen, was labeled by N-monomethylation of the side chain using the classical methylating agent [ 11 C]CH 3 I in 20±5% (decay corrected from [ 11 C]CH 3 I) radiochemical yield. Specific activities obtained ranged from 900-2300Ci/mmol at EOS (end of synthesis). The radiosynthesis, semi-preparative HPLC and formulation were completed in an average time of 45 minutes.