A convenient, high-yield synthesis of [18F]4-fluoroantipyrine using [18F]acetylhypofluorite

Abstract

This paper describes a convenient, high-yield synthesis of [¹⁸F]4-fluoroantipyrine, a blood flow tracer, by fluorination of antipyrine with [¹⁸F]acetylhypofluorite prepared in situ. The radiopharmaceutical was obtained in a radiochemical yield of 28 and 30% following HPLC and Sep-Pak purification, respectively. The two different purification procedures of the crude reaction are described. Sep-Pak filtration, after decomposition of the intermediary of the fluorination reaction by heating with NaOCH₃ in CH₃CN, produced a radiopharmaceutical with radiochemical purity of more than 98%. The synthesis requires 50 min following irradiation.