We first examined the electrophilic substitution of the O-octamethyl EGCG 13 To demonstrate the utility of the method, we planned the synthesis of the methylated EGCGs [ 18 F]18 and [ 18 F]19 possessing a 2,2-bis(hydroxymethyl)-3-[ 18 F]fluoropropyl group, namely a neopentyl labeling unit as PET probes used in positron emission tomography (PET) (Scheme 4). Fluorine-18 is a positron emitter used in positron emission tomography to visualize the location of labeled compounds. The neopentyl labeling group is a hydrophilic labeling group for radiohalogens not only fluoride-18 but also astatine-211 as an a-particle emitter. The hydrophilicity derived from the hydroxymethyl groups could reduce lipophilicity and could contribute greatly to the tolerance against in vivo dehalogenation. The We next investigated the anti-cancer effect of the fluorinated the 8-and 6-subsituted EGCGs 18 and 19 in U266 cells (a human multiple myeloma cell line). (-)-EGCG (1) was used as a positive control.