Table 1. Aniline Alkylation Condition Screeninga.
| entry | solvent | base | temp. (°C) | 1 (HPLC area % at 245 nm)b |
|---|---|---|---|---|
| 1 | EtOH | NaOH | reflux | 3 |
| 2 | EtOH | NaOEt | reflux | 4 |
| 3 | H2O | NaOH | 80 | |
| 4 | acetonitrile | K2CO3 | reflux | 6 |
| 5 | acetonitrile | DBU | reflux | 3 |
| 6 | acetone | Cs2CO3 | reflux | 49 |
| 7 | acetone | K2CO3c | reflux | 6 |
| 8 | acetone | K2CO3d | reflux | 46 |
| 9 | THF | NaH | 20 | 40 |
| 10 | DMF | NaH | 20 | 44 |
| 11 | DMF | NaOH | 80 | 76 |
| 12 | NMP | NaOH | 80 | 68 |
| 13 | diglyme | NaOH | 80 | 82 |
| 14 | diglyme | KOH | 80 | 85 |
| 15 | DMSO | NaOH | 80 | 94 |
| 16 | DMSO | KOH | 80 | 93 |
| 17 | sulfolane | NaOH | 80 | 90 |
| 18 | sulfolane | NaOHe | 80 | 87 |
General reaction conditions: aniline (2, 100 mg, 1 equiv), BBMO (3, 1.2 equiv), and base (2.5 equiv) were added to the solvent (2 mL) in a small vial. This mixture was heated to the listed temperature with stirring for 16 h.
These HPLC data are from an IPC sample taken at the end of the reaction. The percentages are not adjusted for response factors.
KI (0.1 equiv) was added to the reaction mixture.
TBAI (0.1 equiv) was added to the reaction mixture.
Delivered as 50 wt % NaOH (aq).
