Synthesis of N‐{N‐[4‐(4‐{ N ‐[ 11 C]methylamino}phenyl)butyryl]‐L‐prolyl}pyrrolidine: A potential radiotracer for prolyl endopeptidase

Abstract

The synthesis of the 4‐[ 11 C]methylamino derivative of N‐{N‐[4‐(4‐Aminophenyl)butyryl]‐L‐prolyl}pyrrolidine (SUAM‐1221), is described as a potential marker for prolyl endopeptidase for in vivo positron emission tomography studies. Direct methylation of the 4‐amino derivative of SUAM‐1221 ( 1 ) with methyl iodide provided a mixture of the 4‐monomethyl ( 2 ) and 4‐dimethylamino ( 3 ) derivatives which were separated by chromatography. Methylation of 1 with [ 11 C]methyl iodide provided the 4‐[ 11 C]methylamino derivative of SUAM‐1221, ([ 11 C] 2 ), in 18–30% decay corrected radiochemical yield after HPLC purification, with a specific activity > 1700 Ci/mmol and a 40 minute synthesis time from end of bombardment.