Table 2. Optimisation of [11C]1 synthesis using alternative bases.
| Entrya | Base (eq) | TBAI (eq) | Temp (°C) | RCY (%)yb |
|---|---|---|---|---|
| 1c | DBU (3) | 3 | 100 | 6 |
| 2c | DBU (3) | — | 100 | 0 |
| 3 | NaH (1) | 1 | 100 | 26 |
| 4d | NaH (1) | 1 | 60 | 31 ± 2 |
| 5c | NaH (0.5) | 1 | 60 | 18 |
| 6 | NaH (2) | 1 | 60 | 0 |
| 7c | NaH (0.5) | — | 60 | 6 |
| 8 | NaH (1) | 3 | 60 | 7 |
a
Isopropanol (1 equiv., 22 μmol), BzCl (3 equiv.), TBAI (1−3 equiv.), and base (1−3 equiv.) in 500 μL DMF reaction time 5 mins from EOD.
b
The nonisolated radiochemical yield determined by radio-HPLC analysis of the crude product.
c
Reaction time of 10 mins from EOD.
d
n = 3.