C-Labeling of acyclic retinoid peretinoin by rapid C-[C]methylation to disclose novel brain permeability and central nervous system activities hidden in antitumor agent.

Recently, retinoid actions on the central nervous system (CNS) have attracted considerable attention from the perspectives of brain disease diagnosis and drug development. Firstly, we successfully synthesized [C]peretinoin esters (methyl, ethyl, and benzyl) using a Pd(0)-mediated rapid C-[C]methylation of the corresponding stannyl precursors without geometrical isomerization in 82%, 66%, and 57% radiochemical yields (RCYs). Subsequent hydrolysis of the C-labeled ester produced [C]peretinoin in 13 ± 8% RCY (n = 3).