Optimization of Radiofluorination with Varying Parameters and Precursors on Teflon–Glass Substrates
| Condition | Precursor (mM) | PTC/base (mM) | Solvents (v/v) (μL) | Temperature (°C) | Time (min) | Average fluorination efficiency (%)* |
| 1 | Non-Boc (40) | TBAHCO3 (39) | DMSO/TA (0.8/3.2) | 100 | 5 | 47 ± 18 (n = 8) |
| 2 | Boc (40) | K222/K2CO3 (36/18) | DMSO/TA (0.8/3.2) | 100 | 5 | 58 ± 6 (n = 2) |
| 3 | Boc (40) | TBAHCO3 (39) | DMSO/TA (0.8/3.2) | 100 | 5 | 55 ± 19 (n = 3) |
| 4 | Boc (45) | TBAHCO3 (22.5) | DMSO/TA (0.8/3.2) | 110 | 5 | 80 ± 7 (n = 10) |
| 5 | Boc (45) | TBAHCO3 (22.5) | DMSO/MeCN (1/3) | 110 | 5 | 38 ± 4 (n = 2) |
↵* Fluorination efficiencies are reported with SD based on number of experiments, n.
PTC = phase transfer catalyst; non-Boc = 5′-O-dimethoxytrityl-3′-O-nosyl-thymidine; TA = thexyl alcohol; Boc = 3-N-Boc-5′-O-dimethoxytrityl-3′-O-nosyl-thymidine; K222 = Kryptofix 2.2.2; K2CO3 = potassium carbonate.