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

Carbon-11 labeled cyclofenil derivatives, [11C]methyl-2-{4-[bis(4-hydroxyphenyl)methylene]cyclohexyl}acetate ([11C]16a), [11C]methyl-4-[bis(4-hydroxyphenyl)methylene]cyclohexanecarboxylate ([11C]16b), [11C]methyl-2-{3-[bis(4-hydroxyphenyl)methylene]cyclohexyl}acetate ([11C]18a), and [11C]methyl-3-[bis(4-hydroxyphenyl)methylene]cyclohexanecarboxylate ([11C]18b), have been synthesized as new potential PET agents for imaging breast cancer estrogen receptors. The target tracers were prepared by O-[11C]methylation of their corresponding precursors using [11C]CH3OTf 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/μmol specific activity at EOS.