1 H NMR ( 499 . 802 MHz , DMSO ) δ 2 . 59 ( 4 H , t ) , 3 . 63 ( 4 H , t ) , 3 . 81 ( 2 H , s ) , 7 . 57 ( 1 H , d ) , 7 . 86 - 7 . 89 ( 1 H , m ) , 8 . 02 ( 1 H , s ) , 8 . 07 ( 1 H , d ) , 8 . 23 ( 1 H , d ) , 8 . 91 ( 1 H , d ) , 8 . 93 ( 1 H , d ) ; m / z = 415 [ M + H ] +.