Table 3.
The influence of the solvent a.
 | |||
| Entry | Solvent | Time (min) | Yield (%) b |
| 1 | — | 10 ± 1 | 95.2 ± 1.9 |
| 2 c | THF | >24 (h) | 51.5 ± 2.1 |
| 3 c | Acetone | >24 (h) | 54.3 ± 3.2 |
| 4 | MeOH | 66 ± 3 | 93.3 ± 2.7 |
| 5 | EtOH | 57 ± 3 | 94.1 ± 2.5 |
| 6 | 98% EtOH | 25 ± 2 | 94.3 ± 2.8 |
| 7 | 95% EtOH | 15 ± 2 | 95.1 ± 2.6 |
| 8 | 90% EtOH | 10 ± 1 | 94.1 ± 2.3 |
| 9 | 80% EtOH | 9 ± 1 | 93.8 ± 3.1 |
a Reaction conditions: 5.0 mmol of benzaldehyde, 5.0 mmol of malononitrile, 0.15 g of SCB-NH2, 20 mL of solvent, room temperature (25 °C); b Isolated yield; c the yield was determined by GC due to the incomplete conversion of benzaldehyde.