| No. | X | Molecular | Calculated | Experimental |
|---|---|---|---|---|
| Formula | Mass | Mass | ||
| 4a | p-CN | C19H21N5 | 319.1797 amu | 319.1803 amu |
| 4b | p-CO2Me | C20H24N4O2 | 352.1899 amu | 352.1896 amu |
| 4c | p-Br | C18H21N4Br | 372.0949 amu | 372.0952 amu |
| 4d | p-CH3 | C19H24N4 | 308.2001 amu | 308.1997 amu |
| 4e | p-NO2 | C18H21N5O2 | 339.1695 amu | 339.1708 amu |
| 4f | H | C18H22N4 | 294.1844 amu | 294.1853 amu |