1 H NMR ( 499 . 802 MHz , DMSO ) δ 2 . 72 ( 4 H , t ) , 3 . 65 ( 4 H , t ) , 3 . 97 ( 2 H , s ) , 7 . 36 - 7 . 44 ( 2 H , m ) , 7 . 59 ( 1 H , d ) , 7 . 72 - 7 . 77 ( 2 H , m ) , 8 . 25 ( 1 H , d ) ; m / z = 404 [ M + H ] +.