Methods for selecting novel DAA analogues for a peripheral type benzodiazepine receptor were labeled with .sup.18F using one-step syntheses are provided. Analogues labeled with the .sup.18F using the one-step synthesis method are also provided. Additionally, the purification of the Br, I, Cl, TsO, MsO, or R.sub.fSO.sub.3 precursors in the compound of formula (II) by solid phase extraction is provided as is the precursor compounds of formula (II). A kit claim for comprising an effective amount of an .sup.18F labeled compound, and pharmaceutically acceptable salts and solvates thereof are also provided.