| Comp | R | HET | Inhibitiona (%) | IC50 (μM)b | |
| 7 | 5-NH2 |
| 3.44 | NTc | |
| 8 | 6-NH2 |
| 22.02 | NT | |
| 9 | 5-NH2 |
| 0.67 | NT | |
| 10 | 5-NH2 |
| -0.28 | NT | |
| 11 | 6-NH2 |
| 7.56 | NT | |
| 14 | Br |
| 80.78 | 26.22 | |
| 15 | NO2 |
| 16.77 | NT | |
| 16 | NH2 |
| 30.12 | NT | |
| Na3VO4d | - | - | - | 7.43 ± 1.91 | |