1 H NMR ( 700 . 03 MHz , DMSO - d 6 ) δ 2 . 46 ( 4 H , t ) , 3 . 63 ( 4 H , t ) , 4 . 39 ( 1 H , s ) , 7 . 07 - 7 . 23 ( 3 H , m ) , 7 . 33 ( 4 H , t ) , 7 . 48 ( 4 H , d ) , 7 . 51 - 7 . 52 ( 1 H , m ) , 8 . 23 ( 1 H , d ) ; m / z = 471 [ M + H ] +.