1 H NMR ( 499 . 802 MHz , DMSO ) δ 2 . 73 ( 4 H , t ) , 3 . 66 ( 4 H , t ) , 4 . 04 ( 2 H , s ) , 7 . 40 - 7 . 43 ( 1 H , m ) , 7 . 46 - 7 . 51 ( 1 H , m ) , 7 . 60 ( 1 H , d ) , 7 . 94 ( 1 H , d ) , 8 . 06 ( 1 H , d ) , 8 . 25 ( 1 H , d ) ; m / z = 420 [ M + H ] +.