Synthesis and biological evaluation of a new acyclic pyrimidine derivative as a probe for imaging herpes simplex virus type 1 thymidine kinase gene expression

Abstract

With the idea of finding a more selective radiotracer for imaging herpes simplex virus type 1 thymidine kinase (HSV1-tk) gene expression by means of positron emission tomography (PET), a novel [18F]fluorine radiolabeled pyrimidine with 4-hydroxy-3- (hydroxymethyl)butyl side chain at N-1 (HHB-5-[18F]FEP) was prepared and evaluated as a potential PET probe. Unlabeled reference compound, HHB-5-FEP, was synthesized via a five-step reaction sequence starting from 5-(2-acetoxyethyl)-4-methoxypyrimidin-2-one. The radiosynthesis of HHB-[18F]-FEP was accomplished by nucleophilic radiofluorination of a tosylate precursor using [18F]fluoride- cryptate complex in 45% ± 4 (n = 4) radiochemical yields and high purity (>99%). The biological evaluation indicated the feasibility of using HHB-5-[18F]FEP as a PET radiotracer for monitoring HSV1-tk expression in vivo. © 2013 by the authors.