1 H NMR ( 499 . 802 MHz , DMSO ) δ 2 . 58 ( 4 H , t ) , 3 . 63 ( 4 H , t ) , 3 . 76 ( 2 H , s ) , 7 . 55 - 7 . 62 ( 2 H , m ) , 7 . 71 - 7 . 76 ( 1 H , m ) , 7 . 97 ( 1 H , d ) , 8 . 01 ( 1 H , d ) , 8 . 21 - 8 . 26 ( 2 H , m ) , 8 . 88 ( 1 H , d ) ; m / z = 414 [ M + H ] +.