Synthesis of new carbon-11 labeled cyclofenil derivatives for PET imaging of breast cancer estrogen receptors.

Carbon-11 labeled cyclofenil derivatives, [(11)C]methyl-2-{4-[bis(4-hydroxyphenyl)methylene]cyclohexyl}acetate ([(11)C]16a), [(11)C]methyl-4-[bis(4-hydroxyphenyl)methylene]cyclohexanecarboxylate ([(11)C]16b), [(11)C]methyl-2-{3-[bis(4-hydroxyphenyl)methylene]cyclohexyl}acetate ([(11)C]18a), and [(11)C]methyl-3-[bis(4-hydroxyphenyl)methylene]cyclohexanecarboxylate ([(11)C]18b), have been synthesized as new potential PET agents for imaging breast cancer estrogen receptors. The target tracers were prepared by O-[(11)C]methylation of their corresponding precursors using [(11)C]CH(3)OTf and isolated by a simplified SPE purification procedure in 35-50% radiochemical yields decay corrected to EOB, 15-20 min overall synthesis time, and 74-111 GBq/micromol specific activity at EOS.