 | C4X-106110 | N/A | Impurity | |
| Istradefylline Impurity 10 |
| C4X-106111 | 52998-22-8 | Impurity | |
| Istradefylline Impurity 11 |
| C4X-106112 | N/A | Impurity | |
| Istradefylline Impurity 12 |
| C4X-106113 | 14436-34-1 | Impurity | |
| Istradefylline Impurity 13 |
| C4X-106114 | 21237-00-3 | Impurity | |
| Istradefylline Impurity 14 |
| C4X-106115 | 89073-60-9 | Impurity | |
| Istradefylline Impurity 15 |
| C4X-106116 | N/A | Impurity | |
| Istradefylline Impurity 16 |
| C4X-106117 | N/A | Impurity | |
| Istradefylline Impurity 17 (Mixture of Diastereomers) |
| C4X-106118 | 146946-10-3 | Impurity | |
| Istradefylline Impurity 18 |
 | C4X-106119 | 155272-03-0 | Impurity | |
| Istradefylline Impurity 19 |
