Radiosynthesis of N-[11C]-methyl-hydroxyfasudil as a new potential PET radiotracer for rho-kinases (ROCKs)

N-[11C]-methyl-hydroxyfasudil was synthesized as a new potential radiotracer for rho-kinases (ROCKs) via a two-step one-pot radiosynthesis. The first step was the methylation of the precursor N-Boc-hydroxyfasudil-sodium salt/benzo-15-crown-5 complex with [11C]methyl iodide. The second step involved deprotection of the tert-butoxycarbonyl protecting group. The radiochemical and chemical purities of N-[11C]-methyl-hydroxyfasudil were >95% and specific radioactivity was 1565–2565 mCi/μmol at the end of the synthesis.