Table 1.
Cyclisation of xanthohumol (1) with TFA under different reaction conditions 1.
| Temperature 2 | TFA Amount 3 | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| °C | % 4 of 1 | % 4 of 3 | % 4 of 4 | 4/3 | % (v/v) | % 4 of 1 | % 4 of 3 | % 4 of 4 | 4/3 |
| 0 | 54.6 | 9.5 | 35.9 | 3.8 | 0.1 | 97.5 | 0.4 | 2.1 | 5.3 |
| 22 | 16.7 | 16.7 | 66.6 | 4.0 | 0.5 | 46.5 | 9.8 | 43.7 | 4.5 |
| 39 | 0 | 18.7 | 81.3 | 4.3 | 1 | 10.3 | 16.8 | 72.9 | 4.3 |
1 The reaction conditions are specified in the Materials and Methods section. 2 Reactions with 0.8 % (v/v) of TFA. 3 Reactions performed at room temperature. 4 Conversions determined by HPLC.