Table 2.
Radiobromination of diaryl iodonium salts with bromide without base
| Entry | Precursor (5 mg)
|
Solvent (300 μL) | 130 °C Yield (%)1
|
||
|---|---|---|---|---|---|
| R1/R2 | X | 10 min | 30 min | ||
| 1 | Me/Me (4) | OTs | DMSO | 26 | 70 |
| 2 | Me/Me (4) | OTs | DMSO/DMF2 | 89 | 100 |
| 3 | Me/Me (4) | OTs3 | DMF | 67 | 78 |
| 4 | Me/Me (4) | OTs | DMF | 91 | 89 |
| 5 | Me/Me (4) | OTs | H2O/DMF4 | / | 83 |
| 6 | COOMe/H (8) | OTf | DMSO | 965 | 985 |
| 7 | COOH/H (6) | OTf | DMSO | 56/10 | 61/14 |
| 8 | COOH/H (6) | OTf | DMF | 57/13 | 64/18 |
Notes:
1
Radiochemical yield of desired product was determined by HPLC analysis;
2
40 μL DMSO + 300 μL DMF;
3
1 mg precursor;
4
KBr (0.75 mg) in water (30 μL) was mixed with radiobromide;
5
Total yield of two products.