A general method for the synthesis of aryl [11C]methylsulfones:: Potential PET probes for imaging cyclooxygenase-2 expression

A general one-pot method has been developed for the conversion of an aryl thiol moiety masked as the butyrate ester to the corresponding C-11-labeled methylsulfone group. The potential of this methodology has been demonstrated by the successful radiosynthesis of carbon-11 analogues of several highly selective cyclooxygenase-2 (COX-2) inhibitors such as Rofecoxib, Etoricoxib and 3-(4-methylsulfonylphenyl)-4-phenyl-5-trifluoromethyl isoxazole in high yield. The chemical and radiochemical purities obtained for the C-11-labeled COX-2 inhibitors are > 99% with a specific activity > 1000 Ci/mmol. (c) 2005 Elsevier Ltd. All rights reserved.