 | C4X-106122 | 1453190-01-6 | Impurity | |
| Istradefylline Impurity 22 |
 | C4X-106123 | 187393-68-6 | Impurity | |
| Istradefylline Impurity 23 |
| C4X-106124 | 155270-98-7 | Impurity | |
| Istradefylline Impurity 24 |
| C4X-106125 | N/A | Impurity | |
| Istradefylline Impurity 25 |
| C4X-106126 | N/A | Impurity | |
| Istradefylline Impurity 26 |
| C4X-106127 | N/A | Impurity | |
| Istradefylline Impurity 27 |
| C4X-106128 | N/A | Impurity | |
| Istradefylline Impurity 28 |
| C4X-106129 | 5759-63-7 | Impurity | |
| Istradefylline Impurity 29 |
 | C4X-10613 | 155272-04-1 | Impurity | |
| Istradefylline Impurity 3 |
| C4X-10614 | N/A | Impurity | |
| Istradefylline Impurity 4 |
