Preparation of [F-18]beta-CFT-FP and [C-11]beta-CFT-FP, selective radioligands for visualisation of the dopamine transporter using positron emission tomography (PET)

: Kamarainen EL, Kyllonen T, Airaksinen A, Lundkvist C, Yu MX, Nagren K, Sandell J, Langer O, Vepsalainen J, Hiltunen J, Bergstrom K, Lotjonen S, Jaakkola T, Halldin C

Publisher: JOHN WILEY & SONS LTD

: 2000

: Journal of Labelled Compounds and Radiopharmaceuticals

: JOURNAL OF LABELLED COMPOUNDS & RADIOPHARMACEUTICALS

: J LABELLED COMPD RAD

: 43

: 12

: 1235

: 1244

: 10

: 0362-4803

DOI: https://doi.org/10.1002/1099-1344(20001030)43:12<1235::AID-JLCR411>3.0.CO;2-9

In this study the N-fluoropropyl analogue of the cocaine congener beta -CFT (I), N-(3-fluoropropyl)-2 beta -carbomethoxy-3 beta-(4-fluorophenyl) (beta -CFT-FP, III), was labelled with F-18 or C-11. Syntheses of the precursors nor-beta -CFT (II) and beta -CFT-FP acid (IV) as well as III itself are described. [F-18]beta -CFT-FP was prepared starting from I using two different labelling reagents: [F-18]fluoropropyl bromide (V) and [F-18]fluoropropyl tosylate (VI), A reversed-phase HPLC system proved to be effective in separating the labelled product from precursor II. The radiochemical incorporation of V or VI to yield [F-18]beta -CFT-FP (F-18-III) was in general 30-50% and the radiochemical purity was higher than 99%. [C-11]beta -CFT-FP (C-11-III) was synthesised by esterification of IV using [C-11]methyl triflate (VII). An HPLC-purification system using a reversed-phase column proved to be effective in separating the product from the acid precursor. The radiochemical yield starting from [C-11]carbon dioxide was 30-40% and the radiochemical purity was better than 99%. F-18-III and C-11-III have potential as radioligands for visualisation of the dopamine transporter (DAT) using Positron Emission Tomography (PET).