1 H NMR ( 399 . 9 MHz , DMSO - d 6 ) δ 3 . 15 ( 4 H , m ) , 3 . 72 ( 4 H , m ) , 7 . 49 ( 1 H , d ) , 7 . 74 ( 3 H , m ) , 8 . 07 ( 1 H , d ) , 8 . 19 ( 3 H , m ) , 8 . 49 ( 1 H , s ) ; m / z = 463 [ M + H ] +.