3 n boc 5 o dimethoxytrityl 3 o nosyl thymidine

3-N-Boc-5′-O-dimethoxytrityl-3′-O-nosyl-thymidine, 2,3′-anhydro-5′-O-benzoyl-2′-deoxythymidine, 3′-deoxy-3′-fluorothymidine, and tetrabutylammonium hydrogen carbonate (TBAHCO₃, 75 mM in ethanol) were purchased from ABX (Advanced Biochemical Compounds, Radeberg, Germany). All trapping and purification cartridges were purchased from Waters (Milford, MA) or Grace Davison Discovery Sciences (Deerfield, OR). Anhydrous acetonitrile, potassium carbonate (K₂CO₃), dimethyl sulfoxide (DMSO), sodium hydroxide (NaOH), hydrochloric acid (HCl), and Kryptofix-222 were purchased from Sigma-Aldrich (St. Louis, MO), and absolute ethanol (200 proof) from Pharmaco Aaper (Brookfield, CT). Membrane filters (0.2-μm) were purchased from Pall (Port Washington, NY). Manifold kits for FDG were purchased from Rotem Industries, Inc. (Arava, Israel). All radiosyntheses were performed using either a Bioscan Coincidence GE FDG reaction module (Fairfield, CT) or a GE TRACERlab FX_F-N reaction module. Analytical HPLC was performed using a Hitachi HPLC system (LaChrom Elite) equipped with in-line Hitachi UV (LaChrom Elite model L-2400) and radiometric (Carroll-Ramsey Associates, Berkeley, CA) detectors and a Hitachi LaChrom reversed-phase analytical column (150 mm × 4.6 mm). MicroPET scanning was accomplished using a Concorde Microsystems Focus 220 (Siemens, Berlin, Germany).