Synthesis of 1,1′ [11C]-methylene-di-(2-naphthol) (11C]ST1859) for PET studies in humans

1,1'-Methylene-di-(2-naphthol) (ST1859), a candidate drug for the treatment of Alzheimer's disease, was radiolabelled with carbon-11 with the aim to perform PET microdosing studies in humans. The radiosynthesis was automated in a commercial synthesis module (Nuclear Interface PET tracer synthesizer) and proceeded via reaction of [C-11]formaldehyde with 2-naphthol. [C-11]formaldehyde was prepared by catalytic dehydrogenation of [C-11]methanol (conversion yield: 48 +/- 11 % (n = 19)) employing a recently developed silver-containing ceramic catalyst. Starting from 69 +/- 3 GBq of [C-11]carbon dioxide (n = 19), 4 +/- 1 GBq of [C-11]ST1859 (decaycorrected to the end of bombardment), readily formulated for intravenous administration, could be obtained in an average synthesis time of 38 min. The specific radioactivity of [C-11]ST1859 at the end of synthesis exceeded 32 GBq/ mu mol. Copyright (c) 2005 John Wiley & Sons, Ltd.