title: A new, convenient method for the preparation of 4-[18F]fluorobenzyl halides.
abstract: A convenient method suitable for automated preparation of 4-[18F]fluorobenzyl halides from no-carrier-added [18F]fluoride has been developed. 4-[18F]Fluorobenzaldehyde, synthesized from [18F]fluoride by aromatic nucleophilic substitution on 4-trimethylammoniumbenzaldehyde triflate, was first retained on a C18 cartridge and there efficiently reduced to 4-[18F]fluorobenzyl alcohol simply by flowing an aqueous solution of NaBH4. The conversion of 4-[18F]fluorobenzyl alcohol to 4-[18F]fluorobenzyl halide was investigated using PBr3, PI3, P2I4, Ph3PBr2 and Ph3PI2 in CH2Cl2. 4-[18F]Fluorobenzyl halides were purified by passing through a disposable silica cartridge. The conversion rapidly proceeded in radiochemical yields of nearly 90% at 40 degrees C with P2I4 and almost quantitatively at room temperature with Ph3PBr2. With this last reagent 4-[18F]fluorobenzyl bromide was obtained in overall radiochemical yields of 50-60% within 30 min from EOB.
authors.affiliation: CYRIC Tohoku University, Sendai, Japan. rencyric@cyric.tohoku.ac.jp
authors.forename: R
authors.initials: R
authors.lastname: Iwata
authors.forename: C
authors.initials: C
authors.lastname: Pascali
authors.forename: A
authors.initials: A
authors.lastname: Bogni
authors.forename: G
authors.initials: G
authors.lastname: Horvath
authors.forename: Z
authors.initials: Z
authors.lastname: Kovacs
authors.forename: K
authors.initials: K
authors.lastname: Yanai
authors.forename: T
authors.initials: T
authors.lastname: Ido