[PROBLEMS] To provide a novel amino acid organic compound that can be used as a labeledprecursor compound of [F]FACBC and other radioactive halogen labeledamino acid compounds, and that ensures freedom from methanol residue in the producedradioactive halogen labeled amino acid compound. [MEANS FOR SOLVING PROBLEMS]Compounds of the formula: (1) wherein n is 0 or an integer of 1 to 4； Ris an ethyl substituent, 1-propyl substituent or isopropyl substituent； X isa halogen substituent or group of the formula -OR in which Ris a linear or branched-chain C-C haloalkylsulfonatesubstituent, C-C trialkylstannyl substituent, fluorosulfonatesubstituent or aromatic sulfonate substituent； and R is a protectivegroup.
