1 H NMR ( 499 . 802 MHz , DMSO ) δ 2 . 53 ( 4 H , t ) , 3 . 21 ( 3 H , s ) , 3 . 62 ( 4 H , t ) , 3 . 66 ( 2 H , s ) , 7 . 57 ( 1 H , d ) , 7 . 63 ( 1 H , t ) , 7 . 69 ( 1 H , d ) , 7 . 83 ( 1 H , d ) , 7 . 88 ( 1 H , s ) , 8 . 24 ( 1 H , d ) ; m / z = 441 [ M + H ] +.