Potential breast tumor imaging agents: Fluorotamoxifen and derivatives

This study is aimed at developing a ligand to be used for imaging estrogen receptor positive breast tumors by Positron Emission Tomography (PET). We describe the synthesis of fluorotamoxifen analogs with the fluorine atom positioned on the aliphatic side chain of tamoxifen and the measurement of the in vitro binding of fluorotamoxifens to estrogen receptors. N,N-Diethylfluorotamoxifen was prepared from the tosyl ester of the corresponding hydroxy derivative. 18F-Labeled N,N-diethylfluoromethyltamoxifen was prepared in 60% yield. These studies indicate that fluorinated tamoxifens have high affinity for estrogen receptors and can be labeled with 18F, thus reflecting a potential for use in imaging estrogen receptors by PET