A simple loop method for the automated preparation of (11C)raclopride from (11C)methyl triflate

Appl Radiat Isot. 2001 Jul;55(1):17-22. doi: 10.1016/s0969-8043(00)00368-7.

Abstract

A simple automated preparation of [11C]raclopride by reaction of [11C]methyl triflate with demethylraclopride triflate is described. The conventional bubbling of [11C]methyl triflate into the precursor solution was compared with two alternative methods which used a commercially available C18 cartridge (on-column method) or an empty PTFE tube (loop method) as support for the precursor solution. The influence of several solvents was assessed for all three methods. The on-column method showed excellent trapping efficiencies of [11C]methyl triflate but gave the lowest radiochemical yields. The loop method proved to be a simplified alternative to the bubbling method, giving comparable radiochemical yields with less precursor and offering an easy way to transfer the reaction mixture into an HPLC column. By the simple-loop method [11C]raclopride could be prepared in over 40% radiochemical yields (decay-corrected and based on [11C]methyl triflate).

Publication types

  • Comparative Study

MeSH terms

  • Carbon Radioisotopes
  • Chromatography, High Pressure Liquid
  • Isotope Labeling / instrumentation
  • Isotope Labeling / methods
  • Mesylates / chemistry
  • Molecular Structure
  • Raclopride / chemical synthesis*
  • Radiometry / instrumentation
  • Radiometry / methods
  • Radiopharmaceuticals / chemical synthesis*

Substances

  • Carbon Radioisotopes
  • Mesylates
  • Radiopharmaceuticals
  • methyl triflate
  • Raclopride