1 H NMR ( 499 . 8 MHz , DMSO - d 6 ) δ 2 . 56 ( 4 H , t ) , 3 . 62 ( 2 H , s ) , 3 . 64 ( 4 H , t ) , 7 . 48 - 7 . 51 ( 3 H , m ) , 7 . 59 ( 1 H , d ) , 7 . 72 ( 2 H , d ) , 8 . 07 - 8 . 10 ( 1 H , m ) , 8 . 26 ( 1 H , d ) , 8 . 57 - 8 . 58 ( 1 H , m ) , 8 . 91 ( 1 H , d ) ; m / z = 440 [ M + H ] +.