Radiosynthesis of 1-[18F]fluoroethyl-L-tryptophan as a novel potential amino acid PET tracer

Appl Radiat Isot. 2012 Apr;70(4):676-80. doi: 10.1016/j.apradiso.2011.11.062. Epub 2011 Dec 7.

Abstract

(18)F labeled natural amino acids have been introduced as promising tumor imaging agents. A novel [(18)F]fluoro amino acid analog 1-[(18)F]fluoroethyl-L-tryptophan (1-[(18)F]FETrp) was designed and synthesized by a two-pot three-step procedure, including the synthesis of 1-[(18)F]fluoro-2- (tosyloxy)ethane, the [(18)F]fluoroethylation of the precursor N-Boc-L-tryptophan ethyl ester and following the deprotection of the tert-butoxycarbonyl and ethyl ester protecting groups. 1-[(18)F]FETrp was resulted in 0.9 ± 0.2% (n=5) radiochemical yields (no decay corrected) by HPLC purification, within a total synthesis time of 65 min. The radiochemical purity of 1-[(18)F]FETrp was 95-97%. The radiosynthetic method needs to be further optimized to get a satisfying radiochemical yield.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / chemical synthesis
  • Chromatography, High Pressure Liquid
  • Fluorine Radioisotopes*
  • Positron-Emission Tomography / methods*
  • Radiopharmaceuticals / chemical synthesis*
  • Radiopharmaceuticals / isolation & purification
  • Tryptophan / analogs & derivatives*
  • Tryptophan / chemical synthesis
  • Tryptophan / isolation & purification

Substances

  • Amino Acids
  • Fluorine Radioisotopes
  • Radiopharmaceuticals
  • tryptophan ethyl ester
  • Tryptophan