Table 2. Optimization of the Reaction Conditions Using the Model Friedlander Reaction between 2-Amino-3-pyridinecarboxaldehyde (a) and 2-Phenylacetophenone (b)a.
| entry | catalyst | time (h) | T (°C) | IL (mL) | molar ratio (a/b) | yield (%) |
|---|---|---|---|---|---|---|
| 1 | [Bmmim][Im] | 24 | 80 | 5 | 1:1 | 80 |
| 2 | [Bmmim][OH] | 24 | 80 | 5 | 1:1 | 54 |
| 3 | [Bmmim][OC2H5] | 24 | 80 | 5 | 1:1 | 55 |
| 4 | [Bmmim][OCH3] | 24 | 80 | 5 | 1:1 | 45 |
| 5 | [Bmmim][Im] | 24 | 40 | 5 | 1:1 | 56 |
| 6 | [Bmmim][Im] | 24 | 60 | 5 | 1:1 | 67 |
| 7 | [Bmmim][Im] | 24 | 100 | 53 | 1:1 | 74 |
| 8 | [Bmmim][Im] | 18 | 80 | 5 | 1:1 | 67 |
| 9 | [Bmmim][Im] | 21 | 80 | 5 | 1:1 | 71 |
| 10 | [Bmmim][Im] | 27 | 80 | 5 | 1:1 | 49 |
| 11 | [Bmmim][Im] | 24 | 80 | 5 | 0.4:1 | 73 |
| 12 | [Bmmim][Im] | 24 | 80 | 5 | 0.6:1 | 90 |
| 13 | [Bmmim][Im] | 24 | 80 | 5 | 0.8:1 | 88 |
| 14 | [Bmmim][Im] | 24 | 80 | 4 | 0.6:1 | 77 |
| 15 | [Bmmim][Im] | 24 | 80 | 6 | 0.6:1 | 59 |
| 16 | [Bmmim][Im] | 24 | 80 | 3 | 0.6:1 | 62 |
a
Reaction conditions: a and b (1 mmol) were dissolved in ILs.