1 H NMR ( 499 . 8 MHz , DMSO - d 6 ) δ 2 . 56 ( 4 H , t ) , 3 . 63 - 3 . 64 ( 6 H , m ) , 7 . 28 - 7 . 32 ( 2 H , m ) , 7 . 35 ( 1 H , d ) , 7 . 45 ( 1 H , t ) , 7 . 57 ( 3 H , d ) , 7 . 70 - 7 . 73 ( 2 H , m ) , 8 . 25 ( 1 H , d ) ; m / z = 457 [ M + H ] +.